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GEOCHEMISTRY ARTICLES – January 2019?Analytical ChemistryBaile, P., Fernández, E., Vidal, L., Canals, A., 2019. Zeolites and zeolite-based materials in extraction and microextraction techniques. Analyst 144, 366-387.Boduszynski, M.M., Rechsteiner, C.E., Moir, M.E., Leong, D., Nelson, J., Poirier, L., Lopez-Linares, F., 2018. From a dream to a fact: Direct measurement of vanadium and nickel distribution in crude oil cuts fraction (800?1250 °F), in: Ovalles, C., Moir, M.E. (Eds.), The Boduszynski Continuum: Contributions to the Understanding of the Molecular Composition of Petroleum. American Chemical Society, pp. 87-110.Chen, Y.-F., Zong, Z.-M., Li, X.-K., Liu, G.-H., Yang, Z., Jiang, X.-G., Liu, F.-J., Wei, X.-Y., Guo, Q.-J., Zhao, T.-S., Bai, H.-C., Wang, B.-J., 2018. An effective approach for separating carbazole and its derivates from coal-tar-derived anthracene oil using ionic liquids. Energy & Fuels 33, 513–522.Cocovi-Solberg, D.J., Rosende, M., Michalec, M., Miró, M., 2019. 3D printing: The second dawn of lab-on-valve fluidic platforms for automatic (bio)chemical assays. Analytical Chemistry 90, 1140-1149.David, F., Ochiai, N., Sandra, P., 2019. Two decades of stir bar sorptive extraction: A retrospective and future outlook. TrAC Trends in Analytical Chemistry 112, 102-111.Liu, X., Gong, Y., Xiong, W., Cui, L., Hu, K., Che, Y., Zhao, J., 2019. Highly selective detection of benzene, toluene, and xylene hydrocarbons using coassembled microsheets with F?rster resonance energy transfer-enhanced photostability. Analytical Chemistry 91, 768-771.Llompart, M., Celeiro, M., García-Jares, C., Dagnac, T., 2019. Environmental applications of solid-phase microextraction. TrAC Trends in Analytical Chemistry 112, 1-12.Pradhan, A., Ovalles, C., Moir, M., 2018. Characterization of heavy petroleum fractions by NMR techniques, in: Ovalles, C., Moir, M.E. (Eds.), The Boduszynski Continuum: Contributions to the Understanding of the Molecular Composition of Petroleum. American Chemical Society, pp. 73-86.Sun, G., Lu, H., 2019. Recent advances in microfluidic techniques for systems biology. Analytical Chemistry 90, 315-329.Sun, T., Wang, D., Tang, Y., Xing, X., Zhuang, J., Cheng, J., Du, Z., 2019. Fabric-phase sorptive extraction coupled with ion mobility spectrometry for on-site rapid detection of PAHs in aquatic environment. Talanta 195, 109-116.Trujillo-Rodríguez, M.J., Nan, H., Varona, M., Emaus, M.N., Souza, I.D., Anderson, J.L., 2019. Advances of ionic liquids in analytical chemistry. Analytical Chemistry 90, 505-531.Gas Chromatography/GC×GC/GC-MSAlexandrino, G.L., Tomasi, G., Kienhuis, P.G.M., Augusto, F., Christensen, J.H., 2019. Forensic investigations of diesel oil spills in the environment using comprehensive two-dimensional gas chromatography–high resolution mass spectrometry and chemometrics: New perspectives in the absence of recalcitrant biomarkers. Environmental Science & Technology 53, 550-559.Brodsky, E.S., Shelepchikov, A.A., Kalinkevich, G.A., Mir-Kadyrova, E.Y., 2018. Determination of total saturated and total aromatics in oils and oil products by mass spectrometry and gas chromatography/mass spectrometry with electron ionization. Journal of Analytical Chemistry 73, 1372-1375.Flanagan, G., Andrianova, A.A., Casey, J., Hellrung, E., Diep, B.A., Seames, W.S., Kubátová, A., 2019. Simultaneous high-temperature gas chromatography with flame ionization and mass spectrometric analysis of monocarboxylic acids and acylglycerols in biofuels and biofuel intermediate products. Journal of Chromatography A 1584, 165-178.Ghosh, A., Foster, A.R., Johnson, J.C., Vilorio, C.R., Tolley, L.T., Iverson, B.D., Hawkins, A.R., Tolley, H.D., Lee, M.L., 2019. Stainless-steel column for robust, high-temperature microchip gas chromatography. Analytical Chemistry 90, 792-796.Huang, X.-H., Zheng, X., Chen, Z.-H., Zhang, Y.-Y., Du, M., Dong, X.-P., Qin, L., Zhu, B.-W., 2019. Fresh and grilled eel volatile fingerprinting by e-Nose, GC-O, GC–MS and GC?×?GC-QTOF combined with purge and trap and solvent-assisted flavor evaporation. Food Research International 115, 32-43.Ieda, T., Hashimoto, S., Isobe, T., Kunisue, T., Tanabe, S., 2019. Evaluation of a data-processing method for target and non-target screening using comprehensive two-dimensional gas chromatography coupled with high-resolution time-of-flight mass spectrometry for environmental samples. Talanta 194, 461-468.Irvine, B., Erdal, Y.S., Richards, M.P., 2019. Dietary habits in the Early Bronze Age (3rd millennium BC) of Anatolia: A multi-isotopic approach. Journal of Archaeological Science: Reports 24, 253-263.Lebanov, L., Tedone, L., Kaykhaii, M., Linford, M.R., Paull, B., 2019. Multidimensional gas chromatography in essential oil analysis. Part?1: Technical developments. Chromatographia 82, 377-398.Li, H., Qin, D., Wu, Z., Sun, B., Sun, X., Huang, M., Sun, J., Zheng, F., 2019. Characterization of key aroma compounds in Chinese Guojing sesame-flavor Baijiu by means of molecular sensory science. Food Chemistry 284, 100-107.Manzano, C.A., Dodder, N.G., Hoh, E., Morales, R., 2018. Patterns of personal exposure to urban pollutants using personal passive samplers and GC × GC/ToF–MS. Environmental Science & Technology 53, 614-624.Shi, J., Zhu, Y., Zhang, Y., Lin, Z., Lv, H.-P., 2018. Volatile composition of Fu-brick tea and Pu-erh tea analyzed by comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry. LWT - Food Science and Technology 103, 27-33.Skog, K.M., Xiong, F., Kawashima, H., Doyle, E., Soto, R., Gentner, D.R., 2019. Compact, automated, inexpensive, and field-deployable vacuum-outlet gas chromatograph for trace-concentration gas-phase organic compounds. Analytical Chemistry 91, 1318-1327.Temerdashev, Z.A., Musorina, T.N., Kiseleva, N.V., Eletskii, B.D., Chervonnaya, T.A., 2018. Gas chromatography–mass spectrometry determination of polycyclic aromatic hydrocarbons in surface water. Journal of Analytical Chemistry 73, 1154-1161.Temerdashev, Z.A., Pavlenko, L.F., Korpakova, I.G., Ermakova, Y.S., 2018. Analytical aspects of the determination of the total concentration and differentiation of anthropogenic and biogenic hydrocarbons in aquatic ecosystems. Journal of Analytical Chemistry 73, 1137-1145.Wang, K., Xu, Y., Duan, P., Wang, F., Xu, Z.-X., 2019. Thermo-chemical conversion of scrap tire waste to produce gasoline fuel. Waste Management 86, 1-12.Imaging: SEM, TEM, HIM, AFMFan, C., Tang, X., Zhang, Y., Song, Y., Jiang, Z., Luo, Q., Li, B., 2018. Characteristics and formation mechanisms of tight oil: A case study of the Huahai Depression, Jiuquan Basin, Northwest China. Energy Exploration & Exploitation 37, 296-314.Fang, Q., Zhu, D., Agarkova, I., Adhikari, J., Klose, T., Liu, Y., Chen, Z., Sun, Y., Gross, M.L., Van Etten, J.L., Zhang, X., Rossmann, M.G., 2019. Near-atomic structure of a giant virus. Nature Communications 10, Article 388.Fukuma, T., Garcia, R., 2019. Atomic- and molecular-resolution mapping of solid–liquid interfaces by 3D atomic force microscopy. ACS Nano 12, 11785-11797.Gao, Y., Cai, X., Zhang, P., He, G., Gao, Q., Wan, J., 2018. Pore characteristics and evolution of Wufeng–Longmaxi Fms shale gas reservoirs in the basin-margin transition zone of SE Chongqing. Natural Gas Industry B 38, 15-25.Gu, Y., Ding, W., Yin, M., Jiao, B., Shi, S., Li, A., Xiao, Z., Wang, Z., 2018. Nanoscale pore characteristics and fractal characteristics of organic-rich shale: An example from the lower Cambrian Niutitang Formation in the Fenggang block in northern Guizhou Province, South China. Energy Exploration & Exploitation 37, 273-295.Gupta, I., Rai, C., Sondergeld, C., 2019. Study impact of sample treatment and in situ fluids on shale wettability measurement using NMR. Journal of Petroleum Science and Engineering 176, 352-361.Hou, X., Zhu, Y., Jiang, Z., Gao, H., 2018. Geological models and controlling factors of gas content in marine–terrigenous shale in the Southern Qinshui Basin, China. Energy Exploration & Exploitation 37, 375-393.Kebukawa, Y., Kobayashi, H., Urayama, N., Baden, N., Kondo, M., Zolensky, M.E., Kobayashi, K., 2019. Nanoscale infrared imaging analysis of carbonaceous chondrites to understand organic-mineral interactions during aqueous alteration. Proceedings of the National Academy of Sciences 116, 753-758.Keshavarz, V., Khosravanian, R., Taheri-Shakib, J., Salimidelshad, Y., Hosseini, S.A., 2019. Chemical removal of organic precipitates deposition from porous media: Characterizing adsorption and surface properties. Journal of Petroleum Science and Engineering 175, 200-214.Kong, L., Ostadhassan, M., Hou, X., Mann, M., Li, C., 2019. Microstructure characteristics and fractal analysis of 3D-printed sandstone using micro-CT and SEM-EDS. Journal of Petroleum Science and Engineering 175, 1039-1048.Li, Y., Li, Z., Wang, H., Wang, D., 2018. The characteristics of hydrocarbon generation, reserving performances of fine-grained rock, and preservation conditions of coal measure shale gas of an epicontinental sea basin: A case study of the Late Palaeozoic shale gas in the Huanghebei Area of Western Shandong. Energy Exploration & Exploitation 37, 453-472.McCollom, T.M., Donaldson, C., 2019. Experimental constraints on abiotic formation of tubules and other proposed biological structures in subsurface volcanic glass. Astrobiology 19, 53-63.Richert-P?ggeler, K.R., Franzke, K., Hipp, K., Kleespies, R.G., 2019. Electron microscopy methods for virus diagnosis and high resolution analysis of viruses. Frontiers in Microbiology 9, 3255. doi: 3210.3389/fmicb.2018.03255.Rozhnov, S.V., 2018. Hardgrounds of the Ordovician Baltic paleobasin as a distinct type of sedimentation induced by cyanobacterial mats. Paleontological Journal 52, 1098-1113.Schulz, F., Commodo, M., Kaiser, K., De Falco, G., Minutolo, P., Meyer, G., D`Anna, A., Gross, L., 2019. Insights into incipient soot formation by atomic force microscopy. Proceedings of the Combustion Institute 37, 885-892.Shumilova, T.G., Isaenko, S.I., Ulyashev, V.V., Makeev, B.A., Rappenglück, M.A., Veligzhanin, A.A., Ernstson, K., 2018. Enigmatic glass-like carbon from the Alpine Foreland, southeast Germany: A natural carbonization process. Acta Geologica Sinica - English Edition 92, 2179-2200.Song, L., Martin, K., Carr, T.R., Ghahfarokhi, P.K., 2019. Porosity and storage capacity of Middle Devonian shale: A function of thermal maturity, total organic carbon, and clay content. Fuel 241, 1036-1044.Wang, B., Zhang, Q., Wang, G., Liu, M., 2018. Analysis on the difference of material composition and reservoir space of Mesoproterozoic dark marine shale in the Yanshan area. Energy Exploration & Exploitation 37, 332-354.Wang, M., Xie, W., Huang, K., Dai, X., 2019. Fine characterization of lithofacies and pore network structure of continental shale: Case study of the Shuinan Formation in the north Jiaolai Basin, China. Journal of Petroleum Science and Engineering 175, 948-960.Wu, S., Yang, Z., Zhai, X., Cui, J., Bai, L., Pan, S., Cui, J., 2019. An experimental study of organic matter, minerals and porosity evolution in shales within high-temperature and high-pressure constraints. Marine and Petroleum Geology 102, 377-390.Xu, H., Sang, S., Yang, J., Jin, J., Liu, H., Zhou, X., Gao, W., 2018. Evaluation of coal and shale reservoir in Permian coal-bearing strata for development potential: A case study from well LC-1# in the northern Guizhou, China. Energy Exploration & Exploitation 37, 194-218.Xu, L., Wang, Y., Liu, L., Chen, L., Chen, J., 2018. Evolution characteristics and model of nanopore structure and adsorption capacity in organic-rich shale during artificial thermal maturation: A pyrolysis study of the Mesoproterozoic Xiamaling marine shale with type II kerogen from Zhangjiakou, Hebei, China. Energy Exploration & Exploitation 37, 493-518.Zhang, J., Wei, C., Yan, G., Lu, G., 2018. Structural and fractal characterization of adsorption pores of middle–high rank coal reservoirs in western Yunnan and eastern Guizhou: An experimental study of coals from the Panguan syncline and Laochang anticline. Energy Exploration & Exploitation 37, 251-272.Zhang, Q., Amor, K., Galer, S.J.G., Thompson, I., Porcelli, D., 2019. Using stable isotope fractionation factors to identify Cr(VI) reduction pathways: Metal-mineral-microbe interactions. Water Research 151, 98-109.Zhang, Y., Gao, M., You, Q., Fan, H., Li, W., Liu, Y., Fang, J., Zhao, G., Jin, Z., Dai, C., 2019. Smart mobility control agent for enhanced oil recovery during CO2 flooding in ultra-low permeability reservoirs. Fuel 241, 442-450.Zhao, Y., Peng, L., Liu, S., Cao, B., Sun, Y., Hou, B., 2019. Pore structure characterization of shales using synchrotron SAXS and NMR cryoporometry. Marine and Petroleum Geology 102, 116-125.Imaging: X-ray CTFriedrich, J.M., McLain, H.L., Dworkin, J.P., Glavin, D.P., Towbin, W.H., Hill, M., Ebel, D.S., 2019. Effect of polychromatic X-ray microtomography imaging on the amino acid content of the Murchison CM chondrite. Meteoritics & Planetary Science 54, 220-228.Kong, L., Ostadhassan, M., Hou, X., Mann, M., Li, C., 2019. Microstructure characteristics and fractal analysis of 3D-printed sandstone using micro-CT and SEM-EDS. Journal of Petroleum Science and Engineering 175, 1039-1048.Makeen, Y.M., Abdullah, W.H., Abdul Ghofur, M.N., Ayinla, H.A., Hakimi, M.H., Shan, X., Mustapha, K.A., Kamal Shuib, M., Liang, Y., Zainal Abidin, N.S., 2019. Hydrocarbon generation potential of Oligocene oil shale deposit at onshore Penyu Basin, Chenor, Pahang, Malaysia. Energy & Fuels 33, 89-105.Min, X., Hua, H., Cai, Y., Sun, B., 2019. Asexual reproduction of tubular fossils in the terminal Neoproterozoic Dengying Formation, South China. Precambrian Research 322, 18-23.Noiriel, C., Oursin, M., Saldi, G., Haberthür, D., 2019. Direct determination of dissolution rates at crystal surface using 3D X-ray micro-tomography. ACS Earth and Space Chemistry 3, 100-108.Ostvar, S., Iltis, G., Davit, Y., Schlüter, S., Andersson, L., Wood, B.D., Wildenschild, D., 2018. Investigating the influence of flow rate on biofilm growth in three dimensions using microimaging. Advances in Water Resources 117, 1-13.Zhao, Y.-l., Wang, Z.-m., 2019. Multi-scale analysis on coal permeability using the lattice Boltzmann method. Journal of Petroleum Science and Engineering 174, 1269-1278.Ganci, A.P., Vane, C.H., Abdallah, M.A.E., Moehring, T., Harrad, S., 2019. Legacy PBDEs and NBFRs in sediments of the tidal River Thames using liquid chromatography coupled to a high resolution accurate mass Orbitrap mass spectrometer. Science of The Total Environment 658, 1355-1366.Liquid Chromatography/LC-MS/LC×LCAlvarez-Rivera, G., Ballesteros-Vivas, D., Parada-Alfonso, F., Iba?ez, E., Cifuentes, A., 2019. Recent applications of high resolution mass spectrometry for the characterization of plant natural products. TrAC Trends in Analytical Chemistry 112, 87-101.Alvarez-Segura, T., Subirats, X., Rosés, M., 2019. Retention-pH profiles of acids and bases in hydrophilic interaction liquid chromatography. Analytica Chimica Acta 1050, 176-184.Buszewski, B., Walczak, J., Skoczylas, M., Haddad, P.R., 2019. High performance liquid chromatography as a molecular probe in quantitative structure-retention relationships studies of selected lipid classes on polar-embedded stationary phases. Journal of Chromatography A 1585, 105-112.Chan, Q.H.S., Nakato, A., Kebukawa, Y., Zolensky, M.E., Nakamura, T., Maisano, J.A., Colbert, M.W., Martinez, J.E., Kilcoyne, A.L.D., Suga, H., Takahashi, Y., Takeichi, Y., Mase, K., Wright, I.P., 2019. Heating experiments of the Tagish Lake meteorite: Investigation of the effects of short-term heating on chondritic organics. Meteoritics & Planetary Science 54, 104-125.Cheng, S.-C., Bhat, S.M., Lee, C.-W., Shiea, J., 2019. Simple interface for scanning chemical compounds on developed thin layer chromatography plates using electrospray ionization mass spectrometry. Analytica Chimica Acta 1049, 1-9.D’Atri, V., Fekete, S., Clarke, A., Veuthey, J.-L., Guillarme, D., 2019. Recent advances in chromatography for pharmaceutical analysis. Analytical Chemistry 90, 210-239.Dores-Sousa, J.L., De Vos, J., Eeltink, S., 2019. Resolving power in liquid chromatography: A trade-off between efficiency and analysis time. Journal of Separation Science 42, 38-50.Dores-Sousa, J.L., Fernández-Pumarega, A., De Vos, J., L?mmerhofer, M., Desmet, G., Eeltink, S., 2019. Guidelines for tuning the macropore structure of monolithic columns for high-performance liquid chromatography. Journal of Separation Science 42, 522-533.Feng, W., Qiao, J., Li, D., Qi, L., 2019. Chiral ligand exchange capillary electrochromatography with dual ligands for enantioseparation of D,L-amino acids. Talanta 194, 430-436.Fu, L.-l., Ding, H., Han, L.-f., Jia, L., Yang, W.-z., Zhang, C.-x., Hu, Y., Zuo, T.-t., Gao, X.-m., Guo, D.-a., 2019. Simultaneously targeted and untargeted multicomponent characterization of Erzhi Pill by offline two-dimensional liquid chromatography/quadrupole-Orbitrap mass spectrometry. Journal of Chromatography A 1584, 87-96.Ganci, A.P., Vane, C.H., Abdallah, M.A.E., Moehring, T., Harrad, S., 2019. Legacy PBDEs and NBFRs in sediments of the tidal River Thames using liquid chromatography coupled to a high resolution accurate mass Orbitrap mass spectrometer. Science of The Total Environment 658, 1355-1366.Gao, Y., Wu, S., Cong, R., Xiao, J., Ma, F., 2019. Characterization of lignans in Schisandra chinensis oil with a single analysis process by UPLC-Q/TOF-MS. Chemistry and Physics of Lipids 218, 158-167.Garlito, B., Portolés, T., Niessen, W.M.A., Navarro, J.C., Hontoria, F., Monroig, ?., Varó, I., Serrano, R., 2019. Identification of very long-chain (>C24) fatty acid methyl esters using gas chromatography coupled to quadrupole/time-of-flight mass spectrometry with atmospheric pressure chemical ionization source. Analytica Chimica Acta 1051, 103-109.Hansen, R.L., Due?as, M.E., Looft, T., Lee, Y.J., 2019. Nanoparticle microarray for high-throughput microbiome metabolomics using matrix-assisted laser desorption ionization mass spectrometry. Analytical and Bioanalytical Chemistry 411, 147-156.Iguiniz, M., Corbel, E., Roques, N., Heinisch, S., 2019. Quantitative aspects in on-line comprehensive two-dimensional liquid chromatography for pharmaceutical applications. Talanta 195, 272-280.Kartavenka, K., Panuwet, P., Greenwald, R., Ehret, K.M., D'Souza, P.E., Barr, D.B., Ryan, P.B., 2019. Quantification of malondialdehyde in exhaled breath condensate using pseudo two-dimensional ultra-performance liquid chromatography coupled with single quadrupole mass spectrometry. Journal of Chromatography B 1105, 210-216.King, A.C.F., Giorio, C., Wolff, E., Thomas, E., Karroca, O., Roverso, M., Schwikowski, M., Tapparo, A., Gambaro, A., Kalberer, M., 2019. A new method for the determination of primary and secondary terrestrial and marine biomarkers in ice cores using liquid chromatography high-resolution mass spectrometry. Talanta 194, 233-242.Lange, M., Ni, Z., Criscuolo, A., Fedorova, M., 2019. Liquid chromatography techniques in lipidomics research. Chromatographia 82, 77-100.Liang, Y., Zhou, T., 2019. Recent advances of online coupling of sample preparation techniques with ultra high performance liquid chromatography and supercritical fluid chromatography. Journal of Separation Science 42, 226-242.Liigand, J., de Vries, R., Cuyckens, F., 2019. Optimization of flow splitting and make-up flow conditions in liquid chromatography/electrospray ionization mass spectrometry. Rapid Communications in Mass Spectrometry 33, 314-322.Long, Z., Zhan, Z., Guo, Z., Li, Y., Yao, J., Ji, F., Li, C., Zheng, X., Ren, B., Huang, T., 2019. A novel two-dimensional liquid chromatography - Mass spectrometry method for direct drug impurity identification from HPLC eluent containing ion-pairing reagent in mobile phases. Analytica Chimica Acta 1049, 105-114.Ozaki, H., Nakano, Y., Sakamaki, H., Yamanaka, H., Nakai, M., 2019. Basic eluent for rapid and comprehensive analysis of fatty acid isomers using reversed-phase high performance liquid chromatography/Fourier transform mass spectrometry. Journal of Chromatography A 1585, 113-120.Pirok, B.W.J., Stoll, D.R., Schoenmakers, P.J., 2019. Recent developments in two-dimensional liquid chromatography: Fundamental improvements for practical applications. Analytical Chemistry 91, 240-263.Podgornik, A., 2019. Pressure drop in liquid chromatography. Journal of Separation Science 42, 72-88.Raghavan, V., Johnson, J.L., Stec, D.F., Song, B., Zajac, G., Baranska, M., Harris, C.M., Schley, N.D., Polavarapu, P.L., Harris, T.M., 2018. Absolute configurations of naturally occurring [5]- and [3]-ladderanoic acids: Isolation, chiroptical spectroscopy, and crystallography. Journal of Natural Products 81, 2654-2666.Yadav, A., Chattopadhyay, K., Singh, R., Mondal, S., Chopra, A., Christopher, J., Kapur, G.S., 2018. Novel HPLC-RI-UV based method for simultaneous estimation of saturates, olefins, conjugated dienes and aromatics in full range cracked gasoline. Petroleum Science and Technology 36, 1805-1811.Yu, M., Olkowicz, M., Pawliszyn, J., 2019. Structure/reaction directed analysis for LC-MS based untargeted analysis. Analytica Chimica Acta 1050, 16-24.Zoccali, M., Tranchida, P.Q., Mondello, L., 2019. On-line liquid chromatography-comprehensive two dimensional gas chromatography with dual detection for the analysis of mineral oil and synthetic hydrocarbons in cosmetic lip care products. Analytica Chimica Acta 1048, 221-226.Mass Spectroscopy/ICR-FTMS/OrbitrapAlvarez-Rivera, G., Ballesteros-Vivas, D., Parada-Alfonso, F., Iba?ez, E., Cifuentes, A., 2019. Recent applications of high resolution mass spectrometry for the characterization of plant natural products. TrAC Trends in Analytical Chemistry 112, 87-101.Baird, M.A., Anderson, G.A., Shliaha, P.V., Jensen, O.N., Shvartsburg, A.A., 2018. Differential ion mobility separations/mass spectrometry with high resolution in both dimensions. Analytical Chemistry 91, 1479-1485.Chacón-Pati?o, M.L., Rowland, S.M., Rodgers, R.P., 2018. The compositional and structural continuum of petroleum from light distillates to asphaltenes: The Boduszynski Continuum Theory as revealedby FT-ICR mass spectrometry, in: Ovalles, C., Moir, M.E. (Eds.), The Boduszynski Continuum: Contributions to the Understanding of the Molecular Composition of Petroleum. American Chemical Society, pp. 113-stock, K., Ma, S., Sharma, S., Chen, Y., Ding, C., 2019. Enhanced metabolite identification using Orbitrap tribrid mass spectrometer. Drug Metabolism and Pharmacokinetics 34, S32-S33.Coward, E.K., Ohno, T., Sparks, D.L., 2019. Direct evidence for temporal molecular fractionation of dissolved organic matter at the iron oxyhydroxide interface. Environmental Science & Technology 53, 642-650.Dai, J., Zhang, J., Chen, C., 2019. Influence of resins on crystallization and gelation of waxy oils. Energy & Fuels 33, 185-196.Fu, L.-l., Ding, H., Han, L.-f., Jia, L., Yang, W.-z., Zhang, C.-x., Hu, Y., Zuo, T.-t., Gao, X.-m., Guo, D.-a., 2019. Simultaneously targeted and untargeted multicomponent characterization of Erzhi Pill by offline two-dimensional liquid chromatography/quadrupole-Orbitrap mass spectrometry. Journal of Chromatography A 1584, 87-96.Leefmann, T., Frickenhaus, S., Koch, B.P., 2019. UltraMassExplorer: a browser-based application for the evaluation of high-resolution mass spectrometric data. Rapid Communications in Mass Spectrometry 33, 193-202.Niyonsaba, E., Manheim, J.M., Yerabolu, R., Kentt?maa, H.I., 2019. Recent advances in petroleum analysis by mass spectrometry. Analytical Chemistry 90, 156-177.Piga, I., Heijs, B., Nicolardi, S., Giusti, L., Marselli, L., Marchetti, P., Mazzoni, M.R., Lucacchini, A., McDonnell, L.A., 2019. Ultra-high resolution MALDI-FTICR-MSI analysis of intact proteins in mouse and human pancreas tissue. International Journal of Mass Spectrometry 437, 10-16.Solihat, N.N., Acter, T., Kim, D., Plante, A.F., Kim, S., 2019. Analyzing solid-phase natural organic matter using laser desorption ionization ultrahigh resolution mass spectrometry. Analytical Chemistry 90, 951-957.Zhang, L., Peng, Y., Yang, J., 2019. Transformation of dissolved organic matter during advanced coal liquefaction wastewater treatment and analysis of its molecular characteristics. Science of The Total Environment 658, 1334-1343.Zhang, Y.-Y., Wei, X.-Y., Lv, J.-H., Jiang, H., Liu, F.-J., Liu, G.-H., Zong, Z.-M., 2019. Identification of oxygen-containing aromatics in soluble portions from thermal dissolution and alkanolyses of Baiyinhua lignite. Fuel Processing Technology 186, 149-155.Zhao, J., Ye, Q., Wang, P., 2019. Optimization of stepped collision energies of HCD in Orbitrap mass spectrometry for metabolite structure elucidation. Drug Metabolism and Pharmacokinetics 34, S38-S39.Bileck, A., Fluck, C.E., Dhayat, N., Groessl, M., 2019. How high-resolution techniques enable reliable steroid identification and quantification. The Journal of Steroid Biochemistry and Molecular Biology 186, 74-78.Mass Spectroscopy/OtherBarré, F., Rocha, B., Dewez, F., Towers, M., Murray, P., Claude, E., Cillero-Pastor, B., Heeren, R., Porta Siegel, T., 2019. Faster raster matrix-assisted laser desorption/ionization mass spectrometry imaging of lipids at high lateral resolution. International Journal of Mass Spectrometry 437, 38-48.Cheng, S.-C., Bhat, S.M., Lee, C.-W., Shiea, J., 2019. Simple interface for scanning chemical compounds on developed thin layer chromatography plates using electrospray ionization mass spectrometry. Analytica Chimica Acta 1049, 1-9.Fernández, R., Garate, J., Martín-Saiz, L., Galetich, I., Fernández, J.A., 2019. Matrix sublimation device for MALDI mass spectrometry imaging. Analytical Chemistry 91, 803-807.Gaudreau, A.M., Labrie, J., Goetz, C., Dufour, S., Jacques, M., 2018. Evaluation of MALDI-TOF mass spectrometry for the identification of bacteria growing as biofilms. Journal of Microbiological Methods 145, 79-81.Hou, Z., Xiong, X., Fang, X., Huang, G., 2019. Enhanced desorption electrospray ionization mass spectrometry via synchronizing ion generation and ion injection. Journal of The American Society for Mass Spectrometry 30, 368-375.Huang, T., Armbruster, M.R., Coulton, J.B., Edwards, J.L., 2019. Chemical tagging in mass spectrometry for systems biology. Analytical Chemistry 90, 109-125.Kaur, U., Johnson, D.T., Chea, E.E., Deredge, D.J., Espino, J.A., Jones, L.M., 2019. Evolution of structural biology through the lens of mass spectrometry. 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Geochemical characteristics of the Silurian shales from the central Taurides, southern Turkey: Organic matter accumulation, preservation and depositional environment modeling. Marine and Petroleum Geology 102, 155-175.Ela, N.A., Tahoun, S.S., Fouad, T., Mousa, D.A., Saleh, R., 2018. Source rock evaluation of Kharita and Bahariya formations in some wells, North Western Desert, Egypt: Visual palynofacies and organic geochemical approaches. Egyptian Journal of Petroleum 27, 455-465.Gong, D., Song, Y., Wei, Y., Liu, C., Wu, Y., Zhang, L., Cui, H., 2019. Geochemical characteristics of Carboniferous coaly source rocks and natural gases in the Southeastern Junggar Basin, NW China: Implications for new hydrocarbon explorations. International Journal of Coal Geology 202, 171-189.Hamidi, M., Fardoust, F., Jafarzadeh, M., Rabbani, A.R., 2018. Organic geochemistry of the Upper Triassic–Middle Jurassic Shemshak Group (Alborz Mountains, NE Iran). Petroleum Science and Technology 36, 1764-1770.Hu, G., Meng, Q., Wang, J., Tengger, Xie, X., Lu, L., Luo, H., Liu, W., 2018. The original organism assemblages and kerogen carbon isotopic compositions of the Early Paleozoic source rocks in the Tarim Basin, China. Acta Geologica Sinica - English Edition 92, 2297-2309.Huo, Z., Gao, Y., Zhao, Y., Zheng, T., Zhang, J., Ding, J., 2019. Evolution and recovery of original total organic carbon for muddy source rocks with different total organic carbon in the Western Sichuan Depression, Sichuan Basin, China. Geosciences Journal 23, 87-99.Jiang, Z.-R., Zuo, Y.-H., Yang, M.-H., Zhang, Y.-X., Zhou, Y.-S., 2018. Source rocks evaluation of the Paleogene Shahejie 3 Formation in the Dongpu Depression, Bohai Bay Basin. Energy Exploration & Exploitation 37, 394-411.Kayukova, G.P., Mikhailova, A.N., Khasanova, N.M., Morozov, V.P., Vakhin, A.V., Nazimov, N.A., Sotnikov, O.S., Khisamov, R.S., 2018. Influence of hydrothermal and pyrolysis processes on the transformation of organic matter of dense low-permeability rocks from Domanic Formations of the Romashkino oil field. Geofluids 2018, Article 9730642.Li, Z., Yang, W., Wang, Y., Zhang, L., Luo, H., Liu, S., Zhang, L., Luo, X., 2019. Anatomy of a lacustrine stratigraphic sequence within the fourth member of the Eocene Shahejie Formation along the steep margin of the Dongying depression, eastern China. American Association of Petroleum Geologists Bulletin 103, 469-504.Liu, B., Wang, H., Fu, X., Bai, Y., Bai, L., Jia, M., He, B., 2019. Lithofacies and depositional setting of a highly prospective lacustrine shale oil succession from the Upper Cretaceous Qingshankou Formation in the Gulong sag, northern Songliao Basin, northeast China. American Association of Petroleum Geologists Bulletin 103, 405-432.Liu, C., Li, Z., Berhe, A.A., Zeng, G., Xiao, H., Liu, L., Wang, D., Peng, H., 2019. Chemical characterization and source identification of organic matter in eroded sediments: Role of land use and erosion intensity. Chemical Geology 506, 97-112.Liu, H., Yu, B., Xie, Z., Han, S., Shen, Z., Bai, C., 2018. Characteristics and implications of micro-lithofacies in lacustrine-basin organic-rich shale: a case study of Jiyang depression, Bohai Bay Basin. Acta Petrolei Sinica 39, 1328-1343.Liu, P., Wang, X., Horita, J., Fang, X., Zheng, J., Li, X., Meng, Q., 2019. Evaluation of total organic carbon contents in carbonate source rocks by modified acid treatment method and the geological significance of acid-soluble organic matters. Energy Exploration & Exploitation 37, 219-229.Makeen, Y.M., Abdullah, W.H., Abdul Ghofur, M.N., Ayinla, H.A., Hakimi, M.H., Shan, X., Mustapha, K.A., Kamal Shuib, M., Liang, Y., Zainal Abidin, N.S., 2019. Hydrocarbon generation potential of Oligocene oil shale deposit at onshore Penyu Basin, Chenor, Pahang, Malaysia. Energy & Fuels 33, 89-105.Onwe-Moses, F.D., Eze, S.O., Okoro, A.U., Aghamelu, O.P., 2019. Organic geochemical evaluation and hydrocarbon prospects of the Coniacian Awgu Formation, southern Benue Trough, Nigeria. Arabian Journal of Geosciences 12, 77.Palcu, D.V., Popov, S.V., Golovina, L.A., Kuiper, K.F., Liu, S., Krijgsman, W., 2019. The shutdown of an anoxic giant: Magnetostratigraphic dating of the end of the Maikop Sea. Gondwana Research 67, 82-100.Rodrigues, A.R., Pivel, M.A.G., Schmitt, P., de Almeida, F.K., Bonetti, C., 2018. Infaunal and epifaunal benthic foraminifera species as proxies of organic matter paleofluxes in the Pelotas Basin, south-western Atlantic Ocean. Marine Micropaleontology 144, 38-49.Shalaby, M.R., Jumat, N., Lai, D., Malik, O., 2019. Integrated TOC prediction and source rock characterization using machine learning, well logs and geochemical analysis: Case study from the Jurassic source rocks in Shams Field, NW Desert, Egypt. Journal of Petroleum Science and Engineering 176, 369-380.Shi, W., Meng, F., Wang, X., Xu, L., Wu, C., Wang, R., 2018. The evaluation and prediction of source rocks in Huoshiling Formation of Gudian fault depression, south of Songliao Basin. Acta Petrolei Sinica 39, 1344-1354.Smirnov, M.B., Poludetkina, E.N., 2018. Assessment of bioproduction relevance in the photic layer anoxia conditions at the formation of dispersed organic matter of source rocks and oils by mass spectrometry data. Journal of Analytical Chemistry 73, 1364-1371.Wang, N., Li, M., Hong, H., Song, D., Tian, X., Liu, P., Fang, R., Chen, G., Wang, M., 2019. Biological sources of sedimentary organic matter in Neoproterozoic–Lower Cambrian shales in the Sichuan Basin (SW China): Evidence from biomarkers and microfossils. Palaeogeography, Palaeoclimatology, Palaeoecology 516, 342-353.Wang, Y., Qiu, N., Borjigin, T., Shen, B., Xie, X., Ma, Z., Lu, C., Yang, Y., Yang, L., Cheng, L., Fang, G., Cui, Y., 2019. Integrated assessment of thermal maturity of the Upper Ordovician–Lower Silurian Wufeng–Longmaxi shale in Sichuan Basin, China. Marine and Petroleum Geology 100, 447-465.Wang, Y., Xu, S., Hao, F., Lu, Y., Shu, Z., Yan, D., Lu, Y., 2019. Geochemical and petrographic characteristics of Wufeng-Longmaxi shales, Jiaoshiba area, southwest China: Implications for organic matter differential accumulation. Marine and Petroleum Geology 102, 138-154.Wu, J., Liang, C., Hu, Z., Yang, R., Xie, J., Wang, R., Zhao, J., 2019. Sedimentation mechanisms and enrichment of organic matter in the Ordovician Wufeng Formation-Silurian Longmaxi Formation in the Sichuan Basin. Marine and Petroleum Geology 101, 556-565.Xu, H., George, S.C., Hou, D., 2019. Algal-derived polycyclic aromatic hydrocarbons in Paleogene lacustrine sediments from the Dongying Depression, Bohai Bay Basin, China. Marine and Petroleum Geology 102, 402-425.Xu, H., Sang, S., Yang, J., Jin, J., Liu, H., Zhou, X., Gao, W., 2018. Evaluation of coal and shale reservoir in Permian coal-bearing strata for development potential: A case study from well LC-1# in the northern Guizhou, China. Energy Exploration & Exploitation 37, 194-218.Xu, J., Liu, Z., Bechtel, A., Sachsenhofer, R.F., Jia, J., Meng, Q., Sun, P., 2019. Organic matter accumulation in the Upper Cretaceous Qingshankou and Nenjiang Formations, Songliao Basin (NE China): Implications from high-resolution geochemical analysis. Marine and Petroleum Geology 102, 187-201.Yang, L., Ran, B., Han, Y.-Y., Liu, S.-G., Ye, Y.-H., Xiao, C., Sun, W., Yang, D., Xia, G.-D., Wang, S.-Y., 2019. Sedimentary environment controls on the accumulation of organic matter in the Upper Ordovician Wufeng–Lower Silurian Longmaxi mudstones in the Southeastern Sichuan Basin of China. Petroleum Science 16, 44-57.Yu, F., Fu, X., Xu, G., Wang, Z., Chen, W., Zeng, S., Song, C., Feng, X., Wan, Y., Li, X., 2019. Geochemical, palynological and organic matter characteristics of the Upper Triassic Bagong Formation from the North Qiangtang Basin, Tibetan Plateau. Palaeogeography, Palaeoclimatology, Palaeoecology 515, 23-33.Yuan, W., Liu, G., Xu, L., Niu, X., Li, C., 2018. Petrographic and geochemical characteristics of organic-rich shale and tuff of the Upper Triassic Yanchang Formation, Ordos Basin, China: implications for lacustrine fertilization by volcanic ash. Canadian Journal of Earth Sciences 56, 47-59.Zhang, X., Zou, C., Zhao, J., Li, N., Zhang, S., Kouamelan, K.S., Xiao, L., Ma, H., Niu, Y., 2019. Organic-rich source rock characterization and evaluation of the Cretaceous Qingshankou Formation: results from geophysical logs of the second scientific drilling borehole in the Songliao Basin, NE China. Geosciences Journal 23, 119-135.Unconventional ResourcesBakhshian, S., Hosseini, S.A., 2019. Prediction of CO2 adsorption-induced deformation in shale nanopores. Fuel 241, 767-776.Chen, Q., Yan, X., Guo, Y., Hong, T., Nie, H., Zhang, J., Tang, X., Li, W., Liu, C., 2018. Geochemistry, petrology and mineralogy of coal measure shales in the Middle Jurassic Yanan Formation from northeastern Ordos Basin, China: Implications for shale gas accumulation. Acta Geologica Sinica - English Edition 92, 2333-2350.Daly, R.A., Roux, S., Borton, M.A., Morgan, D.M., Johnston, M.D., Booker, A.E., Hoyt, D.W., Meulia, T., Wolfe, R.A., Hanson, A.J., Mouser, P.J., Moore, J.D., Wunch, K., Sullivan, M.B., Wrighton, K.C., Wilkins, M.J., 2019. Viruses control dominant bacteria colonizing the terrestrial deep biosphere after hydraulic fracturing. Nature Microbiology 4, 352-361.Enayatpour, S., van Oort, E., Patzek, T., 2019. Thermal cooling to improve hydraulic fracturing efficiency and hydrocarbon production in shales. Journal of Natural Gas Science and Engineering 62, 184-201.Fan, C., He, S., Zhang, Y., Qin, Q., Zhong, C., 2018. Development phases and mechanisms of tectonic fractures in the Longmaxi Formation Shale of the Dingshan area in southeast Sichuan Basin, China. Acta Geologica Sinica - English Edition 92, 2351-2366.Fan, C., Tang, X., Zhang, Y., Song, Y., Jiang, Z., Luo, Q., Li, B., 2018. Characteristics and formation mechanisms of tight oil: A case study of the Huahai Depression, Jiuquan Basin, Northwest China. Energy Exploration & Exploitation 37, 296-314.Feng, Q., Xu, S., Wang, S., Li, Y., Gao, F., Xu, Y., 2019. Apparent permeability model for shale oil with multiple mechanisms. Journal of Petroleum Science and Engineering 175, 814-827.Gao, Y., Cai, X., Zhang, P., He, G., Gao, Q., Wan, J., 2018. Pore characteristics and evolution of Wufeng–Longmaxi Fms shale gas reservoirs in the basin-margin transition zone of SE Chongqing. Natural Gas Industry B 38, 15-25.Ge, M., Ren, S., Guo, T., Zhou, Z., Wang, S., Bao, S., 2018. Characterizing the micropores in lacustrine shales of the Late Cretaceous Qingshankou Formation of southern Songliao Basin, NE China. Acta Geologica Sinica - English Edition 92, 2267-2279.Gu, Y., Ding, W., Yin, M., Jiao, B., Shi, S., Li, A., Xiao, Z., Wang, Z., 2018. Nanoscale pore characteristics and fractal characteristics of organic-rich shale: An example from the lower Cambrian Niutitang Formation in the Fenggang block in northern Guizhou Province, South China. Energy Exploration & Exploitation 37, 273-295.Gupta, I., Rai, C., Sondergeld, C., 2019. Study impact of sample treatment and in situ fluids on shale wettability measurement using NMR. Journal of Petroleum Science and Engineering 176, 352-361.He, J., Ju, Y., Kulasinski, K., Zheng, L., Lammers, L., 2019. Molecular dynamics simulation of methane transport in confined organic nanopores with high relative roughness. Journal of Natural Gas Science and Engineering 62, 202-213.Hou, X., Zhu, Y., Jiang, Z., Gao, H., 2018. Geological models and controlling factors of gas content in marine–terrigenous shale in the Southern Qinshui Basin, China. Energy Exploration & Exploitation 37, 375-393.Jiang, T., Jin, Z., Liu, G., Liu, Q., Gao, B., Liu, Z., Nie, H., Zhao, J., Wang, R., Zhu, T., Yang, T., 2019. Source analysis of siliceous minerals and uranium in Early Cambrian shales, South China: Significance for shale gas exploration. Marine and Petroleum Geology 102, 101-108.Lee, J.H., Yoo, W., Lee, K.S., 2019. Effects of aqueous solubility and molecular diffusion on CO2-enhanced hydrocarbon recovery and storage from liquid-rich shale reservoirs. Energy Sources, Part A: Recovery, Utilization, and Environmental Effects 41, 1230-1241.Li, F., Wang, M., Liu, S., Hao, Y., 2019. Pore characteristics and influencing factors of different types of shales. Marine and Petroleum Geology 102, 391-401.Li, J., Lu, S., Chen, G., Wang, M., Tian, S., Guo, Z., 2019. A new method for measuring shale porosity with low-field nuclear magnetic resonance considering non-fluid signals. Marine and Petroleum Geology 102, 535-543.Li, Y., Li, Z., Wang, H., Wang, D., 2018. The characteristics of hydrocarbon generation, reserving performances of fine-grained rock, and preservation conditions of coal measure shale gas of an epicontinental sea basin: A case study of the Late Palaeozoic shale gas in the Huanghebei Area of Western Shandong. Energy Exploration & Exploitation 37, 453-472.Liu, A., Ou, W., Huang, H., Wei, K., Li, H., Chen, X., 2018. Significance of paleo-fluid in the Ordovician–Silurian detachment zone to the preservation of shale gas in western Hunan–Hubei area. Natural Gas Industry B 5, 565-574.Liu, J., Zhang, Y., Hu, Z., Li, Y., Yang, X., 2018. An experimental study on the mass transfer mechanism and the flow regime of gas in nano-scale pores of shale gas reservoirs. Natural Gas Industry B 38, 87-95.Liu, K., Wang, L., Ostadhassan, M., Zou, J., Bubach, B., Rezaee, R., 2019. Nanopore structure comparison between shale oil and shale gas: examples from the Bakken and Longmaxi Formations. Petroleum Science 16, 77-93.Luo, S., Lutkenhaus, J.L., Nasrabadi, H., 2019. Experimental study of pore size distribution effect on phase transitions of hydrocarbons in nanoporous media. Fluid Phase Equilibria 487, 8-15.Luo, X., Ren, X., Wang, S., 2019. Supercritical CO2-water-shale interactions and their effects on element mobilization and shale pore structure during stimulation. International Journal of Coal Geology 202, 109-127.Miao, Y., Zhao, C., Wu, K., Li, X., 2019. Analysis of production prediction in shale reservoirs: Influence of water film in inorganic matter. Journal of Natural Gas Science and Engineering 63, 1-9.Rani, S., Padmanabhan, E., Prusty, B.K., 2019. Review of gas adsorption in shales for enhanced methane recovery and CO2 storage. Journal of Petroleum Science and Engineering 175, 634-643.Rivard, C., Bordeleau, G., Lavoie, D., Lefebvre, R., Ladevèze, P., Duchesne, M.J., Séjourné, S., Crow, H., Pinet, N., Brake, V., Bouchedda, A., Gloaguen, E., Ahad, J.M.E., Malet, X., Aznar, J.C., Malo, M., 2019. Assessing potential impacts of shale gas development on shallow aquifers through upward fluid migration: A multi-disciplinary approach applied to the Utica Shale in eastern Canada. Marine and Petroleum Geology 100, 466-483.Song, L., Martin, K., Carr, T.R., Ghahfarokhi, P.K., 2019. Porosity and storage capacity of Middle Devonian shale: A function of thermal maturity, total organic carbon, and clay content. Fuel 241, 1036-1044.Su, S., Jiang, Z., Shan, X., Ning, C., Zhu, Y., Wang, X., Li, Z., Zhu, R., 2019. Effect of lithofacies on shale reservoir and hydrocarbon bearing capacity in the Shahejie Formation, Zhanhua Sag, eastern China. Journal of Petroleum Science and Engineering 174, 1303-1308.Wang, B., Zhang, Q., Wang, G., Liu, M., 2018. Analysis on the difference of material composition and reservoir space of Mesoproterozoic dark marine shale in the Yanshan area. Energy Exploration & Exploitation 37, 332-354.Wang, F., Guo, S., 2019. Influential factors and model of shale pore evolution: A case study of a continental shale from the Ordos Basin. Marine and Petroleum Geology 102, 271-282.Wang, M., Xie, W., Huang, K., Dai, X., 2019. Fine characterization of lithofacies and pore network structure of continental shale: Case study of the Shuinan Formation in the north Jiaolai Basin, China. Journal of Petroleum Science and Engineering 175, 948-960.Wang, R., Sang, S., Jin, J., Zhao, L., Gao, W., Fu, W., Shi, F., Deng, E., 2019. Characteristics and significance of heterogeneity of sea-land transitional facies shale gas reservoir in North Guizhou, China. Geosciences Journal 23, 101-117.Wu, S., Yang, Z., Zhai, X., Cui, J., Bai, L., Pan, S., Cui, J., 2019. An experimental study of organic matter, minerals and porosity evolution in shales within high-temperature and high-pressure constraints. Marine and Petroleum Geology 102, 377-390.Xi, Z., Tang, S., Li, J., Zhang, Z., Xiao, H., 2019. Pore characterization and the controls of organic matter and quartz on pore structure: Case study of the Niutitang Formation of northern Guizhou Province, South China. Journal of Natural Gas Science and Engineering 61, 18-31.Xu, L., Wang, Y., Liu, L., Chen, L., Chen, J., 2018. Evolution characteristics and model of nanopore structure and adsorption capacity in organic-rich shale during artificial thermal maturation: A pyrolysis study of the Mesoproterozoic Xiamaling marine shale with type II kerogen from Zhangjiakou, Hebei, China. Energy Exploration & Exploitation 37, 493-518.Yu, K., Shao, C., Ju, Y., Qu, Z., 2019. The genesis and controlling factors of micropore volume in transitional coal-bearing shale reservoirs under different sedimentary environments. Marine and Petroleum Geology 102, 426-438.Zeng, Q., Wu, Y., Liu, Y., Zhang, G., 2019. Determining the micro-fracture properties of Antrim gas shale by an improved micro-indentation method. Journal of Natural Gas Science and Engineering 62, 224-235.Zhang, C., Yu, Q., 2019. Breakthrough pressure and permeability in partially water-saturated shales using methane–carbon dioxide gas mixtures: An experimental study of Carboniferous shales from the eastern Qaidam Basin, China. American Association of Petroleum Geologists Bulletin 103, 273-301.Zhang, K., Song, Y., Jia, C., Jiang, Z., Jiang, S., Huang, Y., Wen, M., Liu, X., Liu, W., Chen, Z., Xie, X., Liu, T., Wang, X., Wang, P., Li, X., Shan, C.a., 2019. Vertical sealing mechanism of shale and its roof and floor and effect on shale gas accumulation, a case study of marine shale in Sichuan basin, the Upper Yangtze area. Journal of Petroleum Science and Engineering 175, 743-754.Zhao, P., Wang, X., Cai, J., Luo, M., Zhang, J., Liu, Y., Rabiei, M., Li, C., 2019. Multifractal analysis of pore structure of Middle Bakken formation using low temperature N2 adsorption and NMR measurements. Journal of Petroleum Science and Engineering 176, 312-320.Zhao, X., Zhou, L., Pu, X., Han, W., Jin, F., Xiao, D., Shi, Z., Deng, Y., Zhang, W., Jiang, W., 2019. Exploration breakthroughs and geological characteristics of continental shale oil: A case study of the Kongdian Formation in the Cangdong Sag, China. Marine and Petroleum Geology 102, 544-556.Zhao, Y., Peng, L., Liu, S., Cao, B., Sun, Y., Hou, B., 2019. Pore structure characterization of shales using synchrotron SAXS and NMR cryoporometry. Marine and Petroleum Geology 102, 116-125.Zhu, H., Ju, Y., Huang, C., Han, K., Qi, Y., Shi, M., Yu, K., Feng, H., Li, W., Ju, L., Qian, J., 2019. Pore structure variations across structural deformation of Silurian Longmaxi Shale: An example from the Chuandong Thrust-Fold Belt. Fuel 241, 914-932.AbstractsAcosta-Coley, I., Mendez-Cuadro, D., Rodriguez-Cavallo, E., de la Rosa, J., Olivero-Verbel, J., 2019. Trace elements in microplastics in Cartagena: A hotspot for plastic pollution at the Caribbean. Marine Pollution Bulletin 139, 402-411. are new pollutants considered a source of concern for the oceans worldwide. This research reports the concentrations of trace metals on microplastics collected on beaches from Cartagena, an industrialized city in the Caribbean. Mercury (Hg) was quantified using a Hg analyzer and forty-seven trace elements were assessed by ICP/MS. Most abundant microplastics in beaches were those with the lower degree of surface degradation features (SDF), categorized as white-new polyethylene pellets, followed by secondary microplastics (SM). Greater Hg levels were found in SM, white-degraded (WDP) and black pellets. Trace elements concentrations were linked to the degree of SDF registered in examined pellets, with larger concentrations in WDP. Compared to white-new pellets, Ba, Cr, Rb, Sr, Ce, Zr, Ni, Pb were the most accumulated elements in WDP, as their surface enhance the sorption processes. Microplastic pollution represents a toxicological hazard because its ability to accumulate and transport toxic elements.Al-Hawash, A.B., Zhang, X., Ma, F., 2019. Removal and biodegradation of different petroleum hydrocarbons using the filamentous fungus Aspergillus sp. RFC-1. MicrobiologyOpen 8, e00619. Petroleum pollution inevitably occurs at any stage of oil production and exerts a negative impact on the environment. Some microorganisms can degrade petroleum hydrocarbons (PHs). Polluted sludge of Rumaila oil field was use to isolate the highly efficient hydrocarbon-degrading fungal strain. Aspergillus sp. RFC-1 was obtained and its degradation ability for petroleum hydrocarbons was evaluated through surface adsorption, cell uptake, hydrophobicity, surface tension, biosurfactant production, and emulsification activity. In addition, the degradation mechanism was investigated. The results indicated the strain RFC-1 showed high removal activity for PHs, including biodegradation, adsorption, and emulsifiability. On the day 7 of incubation, the removal efficiencies of crude oil, naphthalene (NAP), phenanthrene (PHE), and pyrene (PYR) reached 60.3%, 97.4%, 84.9%, and 90.7%, respectively. Biodegradation efficiencies of crude oil, NAP, PHE, and PYR were 51.8%, 84.6%, 50.3%, and 55.1%, respectively. Surface adsorption and cell absorption by live mycelial pellets followed a decreasing order: PYR?≥?PHE?>?NAP?>?crude oil. Adsorption by heat-killed mycelial pellets increased within 40 and 10?min for crude oil and PAHs, respectively, and remained constant thereafter. Effects of cell surface hydrophobicity, surface tension, and emulsification index were discussed. Intra- and extracellular enzymes of strain RFC-1 played important roles in PHs degradation. The strain RFC-1 is a prospective strain for removing PHs from aqueous environments.Albizuri, S., Nadal, J., Martín, P., Gibaja, J.F., Cólliga, A.M., Esteve, X., Oms, X., Martí, M., Pou, R., López-Onaindia, D., Subirà, M.E., 2019. Dogs in funerary contexts during the Middle Neolithic in the northeastern Iberian Peninsula (5th–early 4th?millennium?BCE). Journal of Archaeological Science: Reports 24, 198-207. this article, a zooarchaeological and isotopic analysis is presented for 26 dog exemplars (Canis familiaris). These dogs were deposited in burial and ceremonial structures in the northeastern Iberian Peninsula during the Middle Neolithic, within the Pit Grave cultural horizon (ca. 4200–3600?cal?BC). Four archaeological sites of the Catalonian coastal strip are studied: Camí de Can Grau, La Serreta, Ca l'Arnella, and Bòbila Madurell (one of the most important necropolises of the Iberian Peninsula). The presence of these dogs is interpreted as evidence of accompanying offerings and represents the most ancient use of this animal in the context of burials within the studied territory. Although it is a not a globally recorded gesture during this period, in light of the present results, it can be considered as a stereotyped ritual activity and evidence of the close relationship between these animals and the human communities. The diet of most of the dogs must be considered mixed and very similar to that of the humans, including consumption of herbivores and terrestrial plants.Alcoriza-Balaguer, M.I., García-Ca?averas, J.C., López, A., Conde, I., Juan, O., Carretero, J., Lahoz, A., 2019. LipidMS: An R package for lipid annotation in untargeted liquid chromatography-data independent acquisition-mass spectrometry lipidomics. Analytical Chemistry 90, 836-845. resolution LC-MS untargeted lipidomics using data independent acquisition (DIA) has the potential to increase lipidome coverage, as it enables the continuous and unbiased acquisition of all eluting ions. However, the loss of the link between the precursor and the product ions combined with the high dimensionality of DIA data sets hinder accurate feature annotation. Here, we present LipidMS, an R package aimed to confidently identify lipid species in untargeted LC-DIA-MS. To this end, LipidMS combines a coelution score, which links precursor and fragment ions with fragmentation and intensity rules. Depending on the MS evidence reached by the identification function survey, LipidMS provides three levels of structural annotations: (i) “subclass level”, e.g., PG(34:1); (ii) “fatty acyl level”, e.g., PG(16:0_18:1); and (iii) “fatty acyl position level”, e.g., PG(16:0/18:1). The comparison of LipidMS with freely available data dependent acquisition (DDA) and DIA identification tools showed that LipidMS provides significantly more accurate and structural informative lipid identifications. Finally, to exemplify the utility of LipidMS, we investigated the lipidomic serum profile of patients diagnosed with nonalcoholic steatohepatitis (NASH), which is the progressive form of nonalcoholic fatty liver disease, a disorder underlying a strong lipid dysregulation. As previously published, a significant decrease in lysophosphatidylcholines, phosphatidylcholines and cholesterol esters and an increase in phosphatidylethanolamines were observed in NASH patients. Remarkably, LipidMS allowed the identification of a new set of lipids that may be used for NASH diagnosis. Altogether, LipidMS has been validated as a tool to assist lipid identification in the LC-DIA-MS untargeted analysis of complex biological samples.Alexandrino, G.L., Tomasi, G., Kienhuis, P.G.M., Augusto, F., Christensen, J.H., 2019. Forensic investigations of diesel oil spills in the environment using comprehensive two-dimensional gas chromatography–high resolution mass spectrometry and chemometrics: New perspectives in the absence of recalcitrant biomarkers. Environmental Science & Technology 53, 550-559. investigations of oil spills aim to find the responsible source(s) of the spill. Oil weathering processes change the chemical composition of the spilled oil and make the matching of oil spill samples to potential sources difficult. Diesel oil spill cases are more challenging, because biomarkers recalcitrant to long-term weathering are absent. We developed and tested a new method for the analysis and matching of diesel oil spills using two-dimensional gas chromatography–high resolution mass spectrometry (GC × GC – HRMS) and 2D-CHEMSIC (2-Dimensional CHEMometric analysis of Selected Ion Chromatograms), an extension of the CHEMSIC method to GC × GC data. The 2D-CHEMSIC performs pixel-based analysis using chemometrics on concatenated sections of 2D extracted ion chromatograms to assess the overall chemical variability of the samples, with potential applications for matching spill-source pairs in forensic investigations. The method was tested on samples from a number of diesel oil spill cases, (i) distinguishing chemically similar source diesels, (ii) investigating weathering effects on spill samples to determine type and degree of weathering, and (iii) improving the matching of diesel oil spills affected by weathering. Positive matches for spill-source pairs were identified after excluding the signals from the hydrocarbons most susceptible to evaporation, and photo-oxidized spills were also matched due to the presence of unaffected hydrocarbons. Forensic diagnostics obtained by the 2D-CHEMSIC were validated by the conventional CEN-Tr method.Almeida, O.G.G., De Martinis, E.C.P., 2019. Bioinformatics tools to assess metagenomic data for applied microbiology. Applied Microbiology and Biotechnology 103, 69-82. reduction of the price of DNA sequencing has resulted in the emergence of large data sets to handle and analyze, especially in microbial ecosystems, which are characterized by high taxonomic and functional diversities. To assess the properties of these complex ecosystems, a conceptual background of the application of NGS technology and bioinformatics analysis to metagenomics is required. Accordingly, this article presents an overview of the evolution of knowledge of microbial ecology from traditional culture-dependent methods to culture-independent methods and the last frontier in knowledge, metagenomics. Topics that will be covered include sample preparation for NGS, starting with total DNA extraction and library preparation, followed by a brief discussion of the chemistry of NGS to help provide an understanding of which bioinformatics pipeline approach may be helpful for achieving a researcher’s goals. The importance of selecting appropriate sequencing coverage and depth parameters to obtain a suitable measure of microbial diversity is discussed. As all DNA sequencing processes produce base-calling errors that compromise data analysis, including genome assembly and microbial functional analysis, dedicated software is presented and conceptually discussed with regard to potential applications in the general microbial ecology field.Alvarez-Majmutov, A., Gieleciak, R., Chen, J., 2019. Modeling the molecular composition of vacuum residue from oil sand bitumen. Fuel 241, 744-752. residue is the most diverse and structurally complex fraction of petroleum. In this work, we develop a representation of the molecular composition of this petroleum fraction. The underlying assumption is that vacuum residue is a continuum in molecular structure that can be described using probability distribution functions. The structural definition of SARA classes (saturates, aromatics, resins, and asphaltenes) is formulated in consistency with recent findings in petroleomics and the chemistry of thermal cracking or conversion. Island- and archipelago-type structures are considered in the representation of resins and asphaltenes. The systematic assembly of residue molecules is executed using stochastic algorithms. The model is implemented with good results in simulating a vacuum residue from oil sand bitumen. The simulation allows visualization of detailed molecular distributions in vacuum residue and its SARA fractions. The model also gives acceptable predictions for the properties of the maltene and asphaltene fractions of the residue sample.Alvarez-Rivera, G., Ballesteros-Vivas, D., Parada-Alfonso, F., Iba?ez, E., Cifuentes, A., 2019. Recent applications of high resolution mass spectrometry for the characterization of plant natural products. TrAC Trends in Analytical Chemistry 112, 87-101., the high analytical power provided by the new HRMS instruments (working in the MS or MS/MS mode, stand alone or hyphenated with separation techniques) is making more feasible the characterization of plant secondary metabolites. In this regard, HRMS-based techniques are becoming the technique of choice, since they are capable of answering many questions regarding the analytical characterization of secondary metabolites, usually found in very complex matrices, including their structural elucidation and quantification in a very fast and sensitive way. In this manuscript we will provide a critical and updated revision of this topic covering the works published in the last 4 years (2015–2018), including the different configurations in which HRMS may be used (stand alone or hyphenated), the data treatment, the strategies for the identification of unknown metabolites, the current software for structure elucidation, as well as the last trends and future outlooks in this hot area of research.Alvarez-Segura, T., Subirats, X., Rosés, M., 2019. Retention-pH profiles of acids and bases in hydrophilic interaction liquid chromatography. Analytica Chimica Acta 1050, 176-184. high proportion of acetonitrile used in many HILIC mobile phases significantly changes the acid-base properties of pH buffers and analytes foreseen from available data in water. In this paper, the recommended stability pH range for chromatographic columns is examined with various acetonitrile/water mixtures, resulting in a significant broadening in the operational pH window with the content of organic solvent. Additionally, the challenge of buffer selection in HILIC is also addressed. Commonly used ammonium acetate shrinks its pH buffering range in acetonitrile-rich mobile phases due to variations in the dissociation constants of the buffer constituents (acetic acid and ammonium). Thus, other organic acids such as formic acid, TFA, and succinimide have been studied as buffers in order to fully cover the pH range of use of the column. Also the retention-pH profiles of several acids and bases have been studied in 80% and 90% acetonitrile using the proposed buffers and their behavior compared to that obtained with buffers prepared from oxalic acid, pyrrolidine, and triethylamine. The latter two show additional interactions in 80% acetonitrile that distort the expected retention-pH profiles of acid analytes, but not the ones of bases. In 90% acetonitrile the profiles are affected by significant additional solute-buffer interactions that might be caused by ion pairing, homo- and heteroassociation in this low ion solvating medium.Amodio, P., Boeckle, M., Schnell, A.K., Ostojíc, L., Fiorito, G., Clayton, N.S., 2019. Grow smart and die young: Why did cephalopods evolve intelligence? Trends in Ecology & Evolution 34, 45-56. in large-brained vertebrates might have evolved through independent, yet similar processes based on comparable socioecological pressures and slow life histories. This convergent evolutionary route, however, cannot explain why cephalopods developed large brains and flexible behavioural repertoires: cephalopods have fast life histories and live in simple social environments. Here, we suggest that the loss of the external shell in cephalopods (i) caused a dramatic increase in predatory pressure, which in turn prevented the emergence of slow life histories, and (ii) allowed the exploitation of novel challenging niches, thus favouring the emergence of intelligence. By highlighting convergent and divergent aspects between cephalopods and large-brained vertebrates we illustrate how the evolution of intelligence might not be constrained to a single evolutionary route.Amorim, M., Santos, M.A.d., Camargo, J.M.R.d., 2019. Methane diffusive fluxes from sediment exposed in a Brazilian tropical reservoir drawdown zone. Journal of South American Earth Sciences 90, 463-470. 2012 and 2015, a severe drought and the consequent decrease in water supply in the southeastern region of Brazil reached concerning levels, leading to a water crisis. This situation caused aerial exposure of some reservoirs drawdown zone. This study aims to measure methane fluxes emitted by this drawdown zone along the Funil hydropower reservoir, Rio de Janeiro, Brazil. It was observed that there was a temporal variation of the methane flux in the sediments exposed in the three scenarios studied: drought, flooding and full (0.43, ?0.31 and ?0.01?mg CH4 m-2 h-1, respectively). The CH4 flux by area in the scenario with the highest exposed sediment area was 0.195 ton CH4 d-1. Considering the values recorded, the contribution of these emissions must become considered in the overall balance of methane in the atmosphere as a new pathway by reservoirs, mainly with the expected forecasts and possible cycles of droughts that may occur frequently. However, the temporal variability of these fluxes indicated the need for future monitoring initiatives that seek to understand how climate change affects the biochemical processes within the exposed sediments of drawdown zones.Andreu-Hayles, L., Levesque, M., Martin-Benito, D., Huang, W., Harris, R., Oelkers, R., Leland, C., Martin-Fernández, J., Anchukaitis, K.J., Helle, G., 2019. A high yield cellulose extraction system for small whole wood samples and dual measurement of carbon and oxygen stable isotopes. Chemical Geology 504, 53-65. paper describes devices to extract α-cellulose from small whole wood samples developed at the Lamont-Doherty Earth Observatory Tree-Ring Lab and explains the procedures for chemical extractions and for the dual analysis of carbon (δ13C) and oxygen (δ13C) stable isotopes. Here, we provide the necessary steps and guidelines for constructing a cellulose extraction system for small amounts of wood and leaves. The system allows the simultaneous extraction of cellulose from 150 samples by means of in-house filter tubes, where chemicals used for the cellulose extraction are exchanged and eliminated in batches. This new implementation diminishes the processing time, minimizes physical sample manipulation and potential errors, increases sample throughput, and reduces the amount of chemicals and analytic costs. We also describe the dual measurement of δ13C and δ18O ratios in tree-ring cellulose using high-temperature pyrolysis in a High Temperature Conversion Elemental Analyzer (TC/EA) interfaced with a Thermo Delta V plus mass spectrometer.Antoshkina, A.I., 2018. Bacteriomorph structures in nodules, a characteristic of euxinic conditions of nodule formation. Paleontological Journal 52, 1114-1125. microscopic, spectroscopic, and geochemical study of Middle Ordovician shamosite, Wenlockian calcite, and Lower Carboniferous siderite nodules revealed the presence of organic matter and traces of microbial organisms involved in the formation of iron oxides and hydroxides and mineralized microbial films. The structure and composition of the films show high similarity to mineralized glycocalyx, which is a product of bacterial metabolism. Diversity of the framboidal micropyrite and bacteriomorph structures in size and shape indicates the formation of nodules under anoxic bottom conditions and abundance of sulfate-reducing, iron-reducing, and iron-oxidizing bacteria. The presence of authigenic minerals in the nodules, which is atypical for sedimentary rocks, suggests the influence of bottom gas–fluid seeps and, therefore, local hydrosulfuric contamination, fluctuations in salinity, and intensive development of bacterial communities.Astafieva, M.M., 2018. Life in ancient cooling lava. Paleontological Journal 52, 1131-1147. study of volcanogenic and volcanogenic–sedimentary rocks (Early Proterozoic pillow lava of Karelia and South Africa), where diverse fossilized bacteria (prokaryotes) and probably even eukaryotes shows that, during this early period, conditions of cooling lava flows and igneous rocks were favorable for bacterial development and colonization.Atwood, E.C., Falcieri, F.M., Piehl, S., Bochow, M., Matthies, M., Franke, J., Carniel, S., Sclavo, M., Laforsch, C., Siegert, F., 2019. Coastal accumulation of microplastic particles emitted from the Po River, Northern Italy: Comparing remote sensing and hydrodynamic modelling with in situ sample collections. Marine Pollution Bulletin 138, 561-574. research has mainly concentrated on open seas, while riverine plumes remain largely unexplored despite their hypothesized importance as a microplastic source to coastal waters. This work aimed to model coastal accumulation of microplastic particles (1–5?mm) emitted by the Po River over 1.5?years. We posit that river-induced microplastic accumulation on adjacent coasts can be predicted using (1) hydrodynamic-based and (2) remote sensing-based modelling. Model accumulation maps were validated against sampling at nine beaches, with sediment microplastic concentrations up to 78?particles/kg (dry weight). Hydrodynamic modelling revealed that discharged particle amount is only semi-coupled to beaching rates, which are strongly mouth dependent and occur within the first ten days. Remote sensing modelling was found to better capture river mouth relative strength, and accumulation patterns were found consistent with hydrodynamic modelling. This methodology lays groundwork for developing an operational monitoring system to assess microplastic pollution emitted by a major river.Baek, S., Min, J., Ahn, Y.-H., Cha, M., Lee, J.W., 2019. Effect of hydrophobic silica nanoparticles on the kinetics of methane hydrate formation in water-in-oil emulsions. Energy & Fuels 33, 523-530. study addresses the effect of hydrophobic silica nanoparticles (SiNPs) on methane hydrate formation in water-in-decane emulsions. Even though the new concept of hydrophobic particle inhibitors has been proposed in the flat interface of oil and bulk water phases, the mechanism of the particle inhibition has not been investigated for a hydrate-forming emulsion system. Numerous experiments with various amounts of SiNPs applied to water-in-decane emulsions and different temperature and pressure profiles have verified how the nanoparticles interact at the interface for hydrate inhibition or promotion. At lower concentrations of SiNPs, they act as a hydrate inhibitor. However, as the amount of SiNPs increases beyond a certain concentration (0.5 wt %), the formation rate anomalously increases because the oil film of the emulsions containing methane becomes thicker with the increasing amount of SiNPs, and water?molecules form capillary bridges along the nanoparticle alignment. Our experimental results and suggested mechanisms provide insights into the interfacial behaviors of SiNPs for preventing hydrate formation in water-in-oil emulsions.Baena-Moreno, F.M., Rodríguez-Galán, M., Vega, F., Alonso-Fari?as, B., Vilches Arenas, L.F., Navarrete, B., 2019. Carbon capture and utilization technologies: a literature review and recent advances. Energy Sources, Part A: Recovery, Utilization, and Environmental Effects 41, 1403-1433. paper presents a comprehensive list of Carbon Capture and Utilization technologies and applications, ranging from lab-scale R&D activities reported in academic papers to commercially established uses of carbon dioxide. Carbon dioxide, as a source of carbon, has the potential to be used as a solvent, as a raw material in the manufacturing of fuels, carbonates, polymers, and chemicals, or as a recovery agent in techniques such as enhanced oil recovery or enhanced coal bed methane. In this paper, a literature review and recent advances of each technology are explained. To finish, most relevant Life Cycle Assessment studies carried out by experts in this field are included. Among the different alternatives studied for the use of carbon dioxide, the processes of carboxylation, consisting the synthesis of carbonates and carboxylates, have stood out. Both the production of salicylic acid as well as that of dimethyl carbonate and mineral carbonation are presented as the most likely applications of carbon dioxide, at least, in the short term.Baile, P., Fernández, E., Vidal, L., Canals, A., 2019. Zeolites and zeolite-based materials in extraction and microextraction techniques. Analyst 144, 366-387. are ordered crystalline materials with a promising performance for a wide range of applications such as catalysis, petrochemistry, environmental remediation, and medicine, but have scarcely been evaluated in Analytical Chemistry. Their unique and fascinating properties such as their high surface area, high adsorption capacity and molecular selectivity, chemical and thermal stability, ion-exchange capacity, low cost extraction and synthesis, and their easy modification, which provides a wide range of zeolite-based materials, make zeolites potential sorbents for extraction procedures. Therefore, in this review, we provide an overview of the current status of zeolites and zeolite-based materials used in extraction and microextraction techniques with reference to recent applications and highlight some of the novel advances.Baird, M.A., Anderson, G.A., Shliaha, P.V., Jensen, O.N., Shvartsburg, A.A., 2018. Differential ion mobility separations/mass spectrometry with high resolution in both dimensions. Analytical Chemistry 91, 1479-1485. orthogonality to mass spectrometry makes differential ion mobility spectrometry (FAIMS) a powerful tool for isomer separations. However, high FAIMS resolution has been achieved overall only with buffers rich in He or H2. That obstructed coupling to Fourier transform mass spectrometers operating under ultrahigh vacuum, but exceptional m/z resolution and accuracy of FTMS are indispensable for frontline biological and environmental applications. By raising the waveform amplitude to 6 kV, we enabled high FAIMS resolution using solely N2 and thus straightforward integration with any MS platform: here Orbitrap XL with the electron transfer dissociation (ETD) option. The initial evaluation for complete histone tails (50 residues) with diverse post-translational modifications on alternative sites demonstrates a broad capability to separate and confidently identify the PTM localization variants in the middle–down range.Baker, M.A.B., Brown, A.J., 2019. A detour to sterol synthesis. Nature Microbiology 4, 214-215. are a hallmark of eukaryotes. So how do hordes of primitive eukaryotes survive and thrive without a key enzyme for making these crucial lipids? We now learn what solution evolution arrived at — invention of an alternative enzyme that does the same job.Bakhshian, S., Hosseini, S.A., 2019. Prediction of CO2 adsorption-induced deformation in shale nanopores. Fuel 241, 767-776. of CO2 adsorption in shale provides significant information about the potential for geological storage of CO2 in shale formations to mitigate the impact of carbon emissions on the climate. This work focuses on the adsorption behavior of CO2 in shale with various pore sizes at a wide temperature range including 31.28?°C, 40?°C, 65?°C, and 90?°C and pressures up to 15?MPa through a comprehensive model. Using a thermodynamic approach, we combine lattice density functional theory with finite element formulation to estimate CO2 adsorption behavior along with its induced strain in shale nanopores. We study the effect of geometric confinement, including pore size and pore geometry, on the excess adsorption and swelling strain of shale under different temperatures. When the model was applied to sorption of CO2 in Posidonia Shale samples, all reported experimental features of the phenomenon were reproduced. Although the developed model applied to the specific case of CO2 adsorption-induced swelling in shale, it is also applicable to any problem regarding adsorption of any fluid confined in a porous medium and its triggered swelling strain. We found that the highly confined geometry of the duct pore, which applies a large attractive surface field to adsorbed layers, leads to a faster, and a higher amount of adsorption compared with that of a slit pore. This effect is more significant in larger pore widths. The results also demonstrate a sharp rise in the adsorption isotherm and swelling strain near the bulk critical point of CO2. This phenomenon attributes to the highly compressive behavior of CO2 near its critical point, which leads to a sharp increase in bulk density and, thus, in adsorbed phase density and its resultant swelling strain. The results also denote that total volumetric strain is a function of temperature, pore width, and pore shape. The effect of pore shape and temperature is more prominent for pores with larger sizes.Baldoni, M., Scorrano, G., Alexander, M., Stasolla, F.R., Marsella, L.T., Rickards, O., Martínez-Labarga, C., 2019. The medieval population of Leopoli-Cencelle (Viterbo, Latium): Dietary reconstruction through stable isotope analysis from bone proteins. Journal of Archaeological Science: Reports 24, 92-101. Medieval period in Europe was a time of unprecedented social complexity and significant social and political change that had an impact on human diets. The present study aims to use stable isotope analysis from bone proteins to explore the diets of humans (n?=?76) and fauna (n?=?5) from the Medieval town of Leopoli-Cencelle (VT, Italy). The town was occupied between the 9th–15th?centuries?CE, however, the analysed remains date to the Late Medieval period (12th–15th?centuries?CE). Historical sources provide some information about the inhabitants of this community: the majority of the population was represented by craftsmen and traders, but farmers and shepherds were also present. To date, no biomolecular data regarding this community have been published. The results indicated an increase of 3–5‰ in δ15N values of humans compared to animals, reflecting a high trophic-level. The δ13C results indicated that animal and human diet was mainly based on C3 terrestrial resources, although three humans possessed an isotopic signature indicative of C4 plant consumption. No statistically significant differences between sexes or age groups (adults vs juveniles) were detected. The isotopic results were further placed in their regional and chronological context, adding valuable data to our understanding of diet and food distribution during the Medieval period in Italy.Balland-Bolou-Bi, C., Bolou-Bi, E.B., Vigier, N., Mustin, C., Poszwa, A., 2019. Increased Mg release rates and related Mg isotopic signatures during bacteria-phlogopite interactions. Chemical Geology 506, 17-28. weathering experiments were carried out under aerobic conditions in a closed system to study Mg isotopic fractionation during the dissolution and processes involved in the presence of bacterial strains. Four different bacterial strains with different metabolisms were chosen. Biotic experiments were performed in batch reactors at 24?°C for 12?days. In parallel, abiotic phlogopite weathering experiments were also performed using organic and nitric acids. Citric and gluconic acids were used to model the effects of chelating agents produced by bacteria, and nitric acid was used to model the effects of acidifying agents. The results indicate that both decreases in pH and the production of metabolites during heterotrophic bacterial activities significantly accelerate the release of Mg and Si in solution. Also, at a given pH, the fraction of elements released in solution is greater in the presence of bacteria or citric acid compared to that released in the presence of nitric and gluconic acids. Magnesium isotopic analyses indicate that the solutions obtained using nitric acid and acidifying bacterial strains display, on average, δ26Mg values that are close to or slightly heavier (by 0.4‰) than those of fresh phlogopite (?1.2‰?±?0.08). In contrast, in experiments performed with citric acid, the Mg leached into solution is slightly enriched in light isotopes by ?0.3‰ relative to the initial phlogopite, while its binding to organics is expected to be related to its preferential enrichment in heavy isotopes. Despite its small range of variations, the δ26Mg values of solutions vary inversely with pH, thus suggesting that secondary phases preferentially enriched in 26Mg at the highest pH values may play a key role.Bancin, L.J., Walther, B.A., Lee, Y.-C., Kunz, A., 2019. Two-dimensional distribution and abundance of micro- and mesoplastic pollution in the surface sediment of Xialiao Beach, New Taipei City, Taiwan. Marine Pollution Bulletin 140, 75-85. pollution with plastic is a growing problem worldwide. This study investigates the microplastic and mesoplastic pollution of Xialiao Beach in northern Taiwan. Sand from the surface (1?cm depth) was collected in a systematic manner. A total of 80 samples were taken along four transects, and plastic particles (≥1?mm) were extracted and quantified. In total, 1939 microplastic particles were recovered, with an average of 96.8 particles per 1?m2. Statistical analysis showed that the backshore had significantly more microplastic particles than the supra littoral or intertidal. Extrapolating the numbers of plastic particles found, approximately 6.8 million plastic particles (≥1?mm) weighing about 250.4?kg should be found in the surface layer of Xialiao Beach. Resampling curves were created from the data set, which showed that at minimum 20 samples should be taken to adequately estimate the mean particle abundance.Bannick, C.G., Szewzyk, R., Ricking, M., Schniegler, S., Obermaier, N., Barthel, A.K., Altmann, K., Eisentraut, P., Braun, U., 2019. Development and testing of a fractionated filtration for sampling of microplastics in water. Water Research 149, 650-658. harmonization of sampling, sample preparation and detection is pivotal in order to obtain comparable data on microplastics (MP) in the environment. This paper develops and proposes a suitable sampling concept for waterbodies that considers different plastic specific properties and influencing factors in the environment. Both artificial water including defined MP fractions and the discharge of a wastewater treatment plant were used to verify the derived sampling procedure, sample preparation and the subsequent analysis of MP using thermal extraction-desorption gas chromatography - mass spectrometry (TED-GC-MS). A major finding of this paper is that an application of various particle size classes greatly improves the practical handling of the sampling equipment. Size classes also enable the TED-GC-MS to provide any data on the MP size distribution, a substantial sampling property affecting both the necessary sampling volume and the optimal sampling depth. In the artificial water with defined MP fractions, the recovery rates ranged from 80 to 110%, depending on the different MP types and MP size classes. In the treated wastewater, we found both polyethylene and polystyrene in different size classes and quantities.Bansal, U., Pande, K., Banerjee, S., Nagendra, R., Jagadeesan, K.C., 2019. The timing of oceanic anoxic events in the Cretaceous succession of Cauvery Basin: Constraints from 40Ar/39Ar ages of glauconite in the Karai Shale Formation. Geological Journal 54, 308-315. study presents 40Ar/39Ar ages of autochthonous glauconites from the lower segment of the onshore Karai Shale Formation of the Cauvery Basin that constrain its age from 100.3 ± 0.7 to 92.6 ± 0.6 Ma. The 40Ar/39Ar plateau ages of the 3 glauconite samples are consistent with the existing biostratigraphic age of Late Albian to Middle Turonian of the Karai Shale Formation. These ages are significant because of the occurrences of oceanic anoxic event (OAE)1d and oceanic anoxic event (OAE)2 in contemporaneous offshore deposits, the Sattapadi Shale and Bhuvanagiri Formation, respectively. Although in the onshore deposits, the glauconite ages mark condensed deposits of the transgressive Karai Shale. As onshore glauconitic deposits may be transitional to organic‐rich black shale deposits offshore in modern and ancient sedimentary settings, the 40Ar/39Ar ages precisely constrains the timing of Cretaceous oceanic anoxic events reported in the Cauvery Basin.Bao, Y., Ju, Y., Huang, H., Yun, J., Guo, C., 2019. Potential and constraints of biogenic methane generation from coals and mudstones from Huaibei coalfield, eastern China. Energy & Fuels 33, 287-295. methane (CBM) resources formed biogenically and thermogenically have been discovered in the Permian coalbeds of the Huaibei coalfield. Four coals, three mudstones, and five coalbed-produced water samples collected from the Linhuan, Luling, and Haizi coal mines of the Huaibei coalfield were characterized geochemically and biologically to gain an understanding of the biogenic methane generation potential and the microbial communities involved in situ and in coalbed-produced water-enriched samples. The 16S rRNA gene high-throughput sequencing results showed that the archaeal communities from in situ and enriched cultures were dominated by Methanolobus and Methanobacterium species. The organic material of coals and mudstones could be biodegraded under an anaerobic incubation. The maximum biogenic methane generation potentials of coal and mudstones were 98.5 and 72.5 μmol/g within 123 days, respectively. Volatile matter and total organic carbon (TOC) content were the most important internal factors affecting biogenic methane generation from coals and mudstones. The Na-SO4 water type resulted in a low methane generation potential.Barré, F., Rocha, B., Dewez, F., Towers, M., Murray, P., Claude, E., Cillero-Pastor, B., Heeren, R., Porta Siegel, T., 2019. Faster raster matrix-assisted laser desorption/ionization mass spectrometry imaging of lipids at high lateral resolution. International Journal of Mass Spectrometry 437, 38-48. clinical use of mass spectrometry imaging (MSI) is rapidly growing, and applications are expanding. Crucially, the analysis of clinical cohorts requires a combination of higher analytical throughput and higher lateral resolution. Here, we demonstrate the benefits of an improved design of a prototype MALDI source (referred as “uMALDI”) mounted on a SYNAPT HDMS G2-Si mass spectrometer – widely used by the MSI community. The uMALDI source allows for imaging of lipids on histologically well documented rat brain sections at a lateral resolution of 15?μm without oversampling. We also investigate the fast rastering capabilities of the platform enabled by a new web-based MS control program (i.e. “WREnS” Waters Research Enabled Software). The combination of the uMALDI and WREnS allows high spatial resolution images at acquisition rates up to 20 pixels per second. Additionally, we demonstrate the capability of this platform to characterize the lipid distribution of osteoarthritic (OA) cartilage at the cellular level, which highlights potential benefit for broader application in clinical context. Finally, we prove that ion mobility separation of isobaric lipid species is maintained and images can be acquired at a rate of 10 scans per seconds. This renders a unique ion mobility mass spectrometric imaging platform with high acquisition rates and high spatial resolution.Bellucci, J.J., Nemchin, A.A., Grange, M., Robinson, K.L., Collins, G., Whitehouse, M.J., Snape, J.F., Norman, M.D., Kring, D.A., 2019. Terrestrial-like zircon in a clast from an Apollo 14 breccia. Earth and Planetary Science Letters 510, 173-185. felsite clast in lunar breccia Apollo sample 14321, which has been interpreted as Imbrium ejecta, has petrographic and chemical features that are consistent with formation conditions commonly assigned to both lunar and terrestrial environments. A simple model of Imbrium impact ejecta presented here indicates a pre-impact depth of 30–70 km, i.e. near the base of the lunar crust. Results from Secondary Ion Mass Spectrometry trace element analyses indicate that zircon grains recovered from this clast have positive Ce/Ce? anomalies corresponding to an oxygen fugacity +2 to +4 log units higher than that of the lunar mantle, with crystallization temperatures of 771±88 to 810 ± 37°C (2σ) that are unusually low for lunar magmas. Additionally, Ti-in-quartz and zircon calculations indicate a pressure of crystallization of 6.9±1.2 kbar, corresponding to a depth of crystallization of 167±27 km on the Moon, contradicting ejecta modelling results. Such low-T, high-fO2, and high-P have not been observed for any other lunar clasts, are not known to exist on the Moon, and are broadly similar to those found in terrestrial magmas.The terrestrial-like redox conditions inferred for the parental magma of these zircon grains and other accessory minerals in the felsite contrasts with the presence of Fe-metal, bulk clast geochemistry, and the Pb isotope composition of K-feldspar grains within the clast, all of which are consistent with a lunar origin. The dichotomy between redox conditions and the depth of origin inferred from the zircon compositions compared to the ejecta modelling necessitates a multi-stage petrogenesis. Two, currently unresolvable hypotheses for the origin and history of the clast are allowed by these data. The first postulates that the relatively oxidizing conditions were developed in a lunar magma, possibly by fractional crystallization and enrichment of incompatible elements in a fluid-rich, phosphate-saturated magma, at the base of the lunar crust to form the zircon grains and their host felsite. Subsequent excavation by the Imbrium impact introduced more typical lunar features to the clast but preserved primary chemical characteristics in zircon and some other accessory minerals. However, this hypothesis fails to explain the high P of crystallization. Alternatively, the felsite and its zircon crystallized on Earth at a modest depth of 19±3 km in the continental crust where oxidizing, low-T, fluid-rich conditions are common. Subsequently, the clast was ejected from the Earth during a large impact, entrained in the lunar regolith as a terrestrial meteorite with the evidence of reducing conditions introduced during its incorporation into the Imbrium ejecta and host breccia.Berrou, K., Dunyach-Remy, C., Lavigne, J.-P., Roig, B., Cadiere, A., 2019. Multiple stir bar sorptive extraction combined with gas chromatography-mass spectrometry analysis for a tentative identification of bacterial volatile and/or semi-volatile metabolites. Talanta 195, 245-250. propose a new approach combining the principles and advantages of stir bar sorptive extraction (SBSE) and headspace sorptive extraction (HSSE). Stir bars have so far never been used for the extraction of volatile/semi-volatile bacterial compounds. The effectiveness of two stir bars with polydimethylsiloxane (PDMS) or ethylene glycol/silicone (EGS) as sorbent was tested by performing sample extraction directly in gas chromatography (GC) vials containing bacterial cultures. Several combinations of desorption and extraction were tested at different growth times. When the extraction was carried out simultaneously with the EGS stir bar in headspace and the PDMS in the bacterial culture, the number of extracted compounds was significantly increased. Using both twisters increased the polarity range of the compounds found, and extraction at the end of the exponential phase of growth generated the best yields. This method was successfully applied to determine the production of 17 molecules by a strain of Staphylococcus aureus. In conclusion, this study paves the way for a new method for determining the volatile metabolite profile of bacteria, which can provide a promising innovative alternative in the identification of biomarkers.Beulig, F., R?y, H., McGlynn, S.E., J?rgensen, B.B., 2019. Cryptic CH4 cycling in the sulfate–methane transition of marine sediments apparently mediated by ANME-1 archaea. The ISME Journal 13, 250-262. in the seabed is mostly oxidized to CO2 with sulfate as the oxidant before it reaches the overlying water column. This microbial oxidation takes place within the sulfate–methane transition (SMT), a sediment horizon where the downward diffusive flux of sulfate encounters an upward flux of methane. Across multiple sites in the Baltic Sea, we identified a systematic discrepancy between the opposing fluxes, such that more sulfate was consumed than expected from the 1:1 stoichiometry of methane oxidation with sulfate. The flux discrepancy was consistent with an oxidation of buried organic matter within the SMT, as corroborated by stable carbon isotope budgets. Detailed radiotracer experiments showed that up to 60% of the organic matter oxidation within the SMT first produced methane, which was concurrently oxidized to CO2 by sulfate reduction. This previously unrecognized “cryptic” methane cycling in the SMT is not discernible from geochemical profiles due to overall net methane consumption. Sedimentary gene pools suggested that nearly all potential methanogens within and beneath the SMT belonged to ANME-1 archaea, which are typically associated with anaerobic methane oxidation. Analysis of a metagenome-assembled genome suggests that predominant ANME-1 do indeed have the enzymatic potential to catalyze both methane production and consumption.Bie, H., Yang, C., Liu, P., 2019. Probabilistic evaluation of above-zone pressure and geochemical monitoring for leakage detection at geological carbon sequestration site. Computers & Geosciences 125, 1-8. monitoring has been proposed as a promising technique for monitoring geological carbon sequestration (GCS) projects for storage integrity. This study presents a probabilistic framework to assess and compare effectiveness of above-zone monitoring of pressure and geochemical parameters for the pilot GCS project at the Cranfield site. Pressure responses in the above-zone monitoring interval (AZMI) to leaks were modeled with a single-phase flow equation and solved analytically and geochemical responses were modeled with a solute transport equation coupled with geochemical reactions, such as mineral dissolution, aqueous complexation, cation exchange, caused by intrusion of the leaked fluids having lower pH and solved semi-analytically. A total of one million realizations were generated using the Monte-Carlo method in terms of 11 parameters required to calculate pressure and geochemical responses to leaks in the AZMI. For each individual realization, time to detect leaks in the AZMI was estimated with pressure with threshold values 200?MPa, 2000?MPa, and 10000?MPa or geochemical parameter (dissolved CO2 in groundwater) with threshold values of 2.33?mmol/kg H2O, 2.82?mmol/kg H2O, 6.94?mmol/kg H2O as indicator and further analyzed statistically over the one million realizations. Our results show that pressure monitoring can detect more than 90% of the leaks whereas geochemical monitoring can detect only up to 50% of the leaks. Detection time ranges from several hours to 200 days for pressure monitoring and from 1 year to 30 years for geochemical monitoring, suggesting that pressure monitoring can provide much early leakage detection. The local relative and global sensitivity analyses were conducted to rank relative importance of the model parameters. Our results show that detection time is sensitive to distance of monitoring well, leakage rate, thickness of the AZMI, and permeability. The global sensitivity analysis shows that the total indices are much higher than the first-order indices, indicating that interactions among the model parameters are crucial to detection time. The probabilistic framework presented in this study can be easily applied to the site configurations of other commercial-scale GCS projects.Bileck, A., Fluck, C.E., Dhayat, N., Groessl, M., 2019. How high-resolution techniques enable reliable steroid identification and quantification. The Journal of Steroid Biochemistry and Molecular Biology 186, 74-78. to possible matrix interferences and artefact generation during sample preparation, careful method validation is required for quantitative bioanalytical methods, especially for analytes that are only present in low concentrations. Using the identification and quantification of progesterone metabolite in the urine of newborns as an example, we show how modern high-resolution instruments can be used to verify analyte assignment and avoid pitfalls commonly encountered by the use of low-resolution instruments.Boduszynski, M.M., Rechsteiner, C.E., Moir, M.E., Leong, D., Nelson, J., Poirier, L., Lopez-Linares, F., 2018. From a dream to a fact: Direct measurement of vanadium and nickel distribution in crude oil cuts fraction (800?1250 °F), in: Ovalles, C., Moir, M.E. (Eds.), The Boduszynski Continuum: Contributions to the Understanding of the Molecular Composition of Petroleum. American Chemical Society, pp. 87-110. Gas Chromatography coupled with Inductively Coupled Plasma Mass Spectrometry (HTGC-ICP-MS) has shown to be a powerful technique to determine metal distribution as a function of boiling point. From the early days using the original prototype, the concept was proven and illustrated the potential of this technique for the vanadium and nickel fingerprint analysis of deep-cut vacuum gas oil (VGO) fractions (800-1250 °F). The technique shows that these elements are present at temperatures as low as 1040 °F and can be distributed in a narrow or broad boiling point range depending on the parent crude. With the advance of the technology, commercial instrumentation has become available that enable this technique to become routine. Different fractions from crude oils from around the world show that these elements can be distributed in different temperature ranges. Initial vanadium speciation analysis for a VGO fraction from a North American crude reveals that the most common porphyrin type structures are etioporphyrins. Finally, this technique can be extended to other elements beyond vanadium and nickel such as arsenic, selenium, iron, sulfur, iodine, among others to assess how they are distributed in crude oil by boiling point.Boltyanskaya, Y.V., Kevbrin, V.V., 2018. Laboratory simulation of “proteolytic bacterium–cyanobacterium” interaction in alkaliphilic microbial community. Paleontological Journal 52, 1179-1185. work continues the series of long-term studies of the microbial diversity of soda lakes and concerns the problem of anaerobic decomposition of proteins. The physiology of new proteolytic bacteria has been investigated. The lytic effect of the alkaliphilic anaerobe Proteinivorax tanatarense on other members of community, primarily cyanobacteria, has been demonstrated. P. tanatarense proved to be a saprotrophic satellite regulating the number of cyanobacteria under night conditions. The directed effects of P. tanatarense on phototrophic and chemotrophic Gram-negative microorganisms were demonstrated as well as the absence of its effect on any Gram-positive microorganisms. Such specialization of proteolytic agent could be implemented in cyanobacterial communities of the past.Bono, R.K., Tarduno, J.A., Nimmo, F., Cottrell, R.D., 2019. Young inner core inferred from Ediacaran ultra-low geomagnetic field intensity. Nature Geoscience 12, 143-147. enduring mystery about Earth has been the age of its solid inner core. Plausible yet contrasting core thermal conductivity values lead to inner core growth initiation ages that span 2 billion years, from ~0.5 to >2.5 billion years ago. Palaeomagnetic data provide a direct probe of past core conditions, but heretofore field strength data were lacking for the youngest predicted inner core onset ages. Here we present palaeointensity data from the Ediacaran (~565?million?years old) Sept-?les intrusive suite measured on single plagioclase and clinopyroxene crystals that hosted single-domain magnetic inclusions. These data indicate a time-averaged dipole moment of ~0.7?×?1022?A?m2, the lowest value yet reported for the geodynamo from extant rocks and more than ten times smaller than the strength of the present-day field. Palaeomagnetic directional studies of these crystals define two polarities with an unusually high angular dispersion (S?=?~26°) at a low latitude. Together with 14 other directional data sets that suggest a hyper-reversal frequency, these extraordinary low field strengths suggest an anomalous field behaviour, consistent with predictions of geodynamo simulations, high thermal conductivities and an Ediacaran onset age of inner core growth.Bostick, B.C., 2019. Massive ore deposits from microscopic organisms. Geology 47, 191-192. ore deposits are the result of a sequence of processes that concentrate a compound or element in a small volume that is amenable to recovery. In many cases, copper sulfides precipitate with much more abundant pyrite in massive sulfides that are hydrothermal or volcanogenic in origin. Many of the world’s largest and highest quality copper deposits are formed from the secondary concentration of copper from these massive sulfides. These secondary deposits form by oxidation of pyrite through exposure to oxygen, which produces sulfuric acid, insoluble secondary iron oxyhydroxides and occasionally sulfates, and a host of more soluble metals including copper. These metal ions are transported in aqueous solution downward to an anaerobic zone where sulfate reduction creates sulfide, and concentrates (CuS) or chalcocite (Cu2S) within a cementation zone. Although pyrite oxidation is well known to be catalyzed by microbial species such as Thiobacillus spp. (Morse, 1991; Baker and Banfield, 2003; Nordstrom, 2011), the reduction processes resulting in copper sulfide formation have usually been attributed to purely chemical processes. Tornos et al. (2019, p. 143 in this issue of Geology,) provide compelling evidence for the direct involvement of microbial processes in the mineralization of these deposits. In doing so, they provide the strongest evidence to date that these large secondary copper deposits are formed by the combination of sulfur redox cycling coupled with transport and provide much-needed clues about the factors that influence the origin of these deposits.In the study, a combination of imaging, genomic, and metabolic studies were performed to determine the metabolisms that were active within the Las Cruces copper deposit in southwestern Spain, which has undergone secondary mineralization for the past 85 m.y. (Tornos, 2006; Tornos et al., 2017). Of particular note, the authors make use of catalyzed reporter deposition (CARD)-fluorescence in situ hybridization (FISH) probes, which are particularly powerful in that they can be used to image specific metabolic functions. Within the cementation zone, CARD-FISH revealed aggregates of sulfate-reducing bacteria, methanogens, and other organisms within exopolysaccharides (EPS) that were concentrated along vein walls, and crystals of copper sulfides were associated intimately with these matrices. Importantly, these veins also contained abundant organic matter and revealed a complex fabric on which the bulk of mineralization occurred. Such architectures are commonplace in biofilms where organisms anchor themselves within a chemical gradient, but seldom directly observed in ore deposits (Sillitoe et al., 1996). In this case, these organisms appear to be organized within a vein to take advantage of abundant sulfate, organic carbon, or hydrogen within the vein. It is likely that this deposit is similar to others, yet the reasons that these structures are only rarely preserved remain unsolved, though most other studies have depended on identifying microbial morphologies in the veins rather than genomic methods of identifying organisms or organism function.These microorganisms appear to be more than relict structures. Enrichment cultures from mineralization zones released hydrogen gas and consumed sulfate, both indications of viable, or at least potentially active, sulfate reduction. Furthermore, the reported quantities of sulfate consumed are quite high, and viable cell densities appear to be as high as 107–108 cells/g. For comparison, this cell density is nearly on par with cell densities observed in subsurface soils (Fierer et al., 2003; Rousk et al., 2010) where abundant nutrients and energy sources are available. The abundance of viable organisms is particularly striking given the age of the ore deposit, and begs a series of questions about how these organisms have maintained viability, or if the vein is still actively forming despite its hydrologic isolation. The enrichment culture results suggest that these organisms are capable of efficient metabolisms, and thus potentially much more rapid mineralization than is usually presumed in these deposits. One possible factor that would slow mineralization is that it requires an energy source or electron donor, and this energy source also must be delivered to the microbial community. Hydrogen gas is likely to be the principal electron donor for these microbial communities, and it is probably derived from the thermal decomposition of organic matter within the underlying rocks. The Iberian Belt contains sediment rocks with abundant organic carbon, and this thermogenic (or methanogenic) gas is likely the product of slow diagenesis of those hydrocarbons (Inverno et al., 2015; Puente-Sánchez et al., 2018), producing methane and hydrogen, and the transport of those gases upward to the mineralization zone. If the release of hydrogen was really very slow, however, then presumably the chemical gradients that result from them would also be low, and thus they would likely support relatively lower densities of microbial life than were observed, but more adapted to the chemical environment.One of the most compelling aspects of the study is the identities of the microorganisms identified in these secondary deposits. While it is tempting to label such an environment “extreme,” many of the organisms identified are quite pedestrian, or at least common in nature. Some of the species identified include Crenarchaeota, sulfate-reducing bacteria such as Desulfosporosinus, Desulfitobacterium, Desulfotomaculum, and Desulfovibrio sp., and methanogenic archaea of the Methanosarcinales order such as Methanosarcina. Many of these bacteria might be encountered in rice paddys similar to where Desulfovibrio was isolated originally (Dalsgaard and Bak, 1994) or in other anaerobic soil, an estuary, or groundwater environment. Of these, Desulfotomaculum is unique in that it has been identified as a key sulfate reducer found in the deep and warm biosphere typical of low-temperature hydrothermal conditions (～100 °C) thought to be prevalent at the site (Moser et al., 2005; Aüllo et al., 2013).Cultures also contained less-abundant iron cycling organisms, as well as many other undetermined microorganisms having unknown roles. Given the abundance of iron, this should not be surprising, and it could play an active role in the formation of the ore deposit. There is accumulating evidence that secondary sulfide mineral formation depends on the careful buffering of hydrogen sulfide concentrations. Many metals that form insoluble sulfide minerals, including copper, but including other elements like arsenic, also are capable of forming soluble sulfide complexes. As such, the solubility of the metal does not simply decrease as sulfide activities increase, but rather there is a minimum in which the metal is least soluble. In the case of arsenic, this occurs at a sulfide activity of just under 1 ?M (Eary, 1992), and in the case of copper, it is complicated by the chemical state of Cu(I)/Cu(II) redox cycling, but also favored at low sulfide activities (Helz et al., 1993; Thompson and Helz, 1994). The separation and enrichment of Cu from other metals is possible only because of the unique stability of each of these sulfide complexes, and it is likely that the redox cycling of iron helps maintain low sulfide concentrations, and thus enhance metal sulfide solubility (Saalfield and Bostick, 2009; Burton et al., 2011). In future work, hopefully the roles of these parallel redox processes can better be constrained.Overall, microbial sulfate reduction appears to be a key process in the formation of large secondary sulfide deposits in Las Cruces, Spain, and likely in others. There are abundant microorganisms facilitating sulfide reduction, and the reduction of other species including iron can carbon dioxide. Most of those bacteria are relatively commonplace in the environment, and the structures that form in the veins of these deposits appear to be similar to a host of other biofilms, in a variety of geochemical gradients. There is an intriguing and perhaps hidden suggestion from these conventional observations in an unconventional environment; namely, that perhaps an equivalent environmental setting would inherently contain these organisms and minerals, and that they would be using similar metabolisms elsewhere in the world. If so, then it would follow that this study is a reminder that it is the geological setting that supplies the reactants like sulfate and hydrogen gas for sulfate reduction to proceed, and thus controls secondary sulfide deposit formation. The ore deposit is thus rare not because the biological community is rare, but because the habitat these organisms occupy is limited to an uncommon geological setting. Similarly, this ore deposit is large because the geochemical conditions that create microbial substrates, and the transport of them to the mineralization zone, are stable and persistent. As such, understanding the role of biology in shaping ore deposits, and indeed our planet, requires us to examine the physical hydrology, petrology, and geochemistry that controls the formation of biological substrates. Of these factors, we have focused much effort on the geochemistry, but we know much less about how biology couples to transport processes in these ore deposits. Perhaps the isotopic data will be helpful in this regard. In some cases, isotopic fractionation between sulfate and secondary sulfides is negligible (e.g., Enders et al., 2006), indicating that the reduction is either abiotic or complete (the isotopic composition of sulfate are sulfide would be equivalent if it is entirely consumed). In more open systems, the isotopic composition of sulfide should be significantly different from the sulfate because of physical separation between them (Bawden et al., 2003). In either case, there are obvious parallels between the formation of these sulfide deposits and the common coupled redox processes observed in soils and sediments, both of which can only be fully appreciated with a broad geological perspective.Bralower, T.J., Kump, L.R., Self-Trail, J.M., Robinson, M.M., Lyons, S., Babila, T., Ballaron, E., Freeman, K.H., Hajek, E., Rush, W., Zachos, J.C., 2018. Evidence for shelf acidification during the onset of the Paleocene-Eocene thermal maximum. Paleoceanography and Paleoclimatology 33, 1408-1426. transect of paleoshelf cores from Maryland and New Jersey contains an ~0.19- to 1.61-m-thick interval with reduced percentages of carbonate during the onset of the Paleocene-Eocene Thermal Maximum (PETM). Outer paleoshelf cores are barren of nannofossils and correspond to two minor disconformities. Middle paleoshelf cores contain a mixture of samples devoid of nannofossils and those with rare specimens characterized by significant dissolution (i.e., etching). The magnitude of the decrease in carbonate cannot be explained by dilution by clastic material or dissolution resulting from the oxidation of organic matter during early diagenesis. The observed preservation pattern implies a shoaling of the calcite compensation depth and lysocline to the middle shelf. This reduced carbonate interval is observed during the onset of the PETM on other continental margins raising the possibility that extreme shoaling of the calcite compensation depth and lysocline was a global signal, which is more significant than in previous estimates for the PETM. An alternative scenario is that shoaling was restricted to the northwest Atlantic, enhanced by regional and local factors (eutrophication from rivers and microbial activity associated with warming) that exacerbated the impact of acidification on the shelf.Brankovits, D., Pohlman, J.W., Ganju, N.K., Iliffe, T.M., Lowell, N., Roth, E., Sylva, S.P., Emmert, J.A., Lapham, L.L., 2018. Hydrologic controls of methane dynamics in karst subterranean estuaries. Global Biogeochemical Cycles 32, 1759-1775. subterranean estuaries (KSEs) extend into carbonate platforms along 12% of all coastlines. A recent study has shown that microbial methane (CH4) consumption is an important component of the carbon cycle and food web dynamics within flooded caves that permeate KSEs. In this study, we obtained high‐resolution (~2.5‐day) temporal records of dissolved methane concentrations and its stable isotopic content (δ13C) to evaluate how regional meteorology and hydrology control methane dynamics in KSEs. Our records show that less methane was present in the anoxic fresh water during the wet season (4,361 ± 89 nM) than during the dry season (5,949 ± 132 nM), suggesting that the wet season hydrologic regime enhances mixing of methane and other constituents into the underlying brackish water. The δ13C of the methane (?38.1 ± 1.7‰) in the brackish water was consistently more 13C‐enriched than fresh water methane (?65.4 ± 0.4‰), implying persistent methane oxidation in the cave. Using a hydrologically based mass balance model, we calculate that methane consumption in the KSE was 21–28 mg CH4·m?2·year?1 during the 6‐month dry period, which equates to ~1.4 t of methane consumed within the 102‐ to 138‐km2 catchment basin for the cave. Unless wet season methane consumption is much greater, the magnitude of methane oxidized within KSEs is not likely to affect the global methane budget. However, our estimates constrain the contribution of a critical resource for this widely distributed subterranean ecosystem.Brodsky, E.S., Shelepchikov, A.A., Kalinkevich, G.A., Mir-Kadyrova, E.Y., 2018. Determination of total saturated and total aromatics in oils and oil products by mass spectrometry and gas chromatography/mass spectrometry with electron ionization. Journal of Analytical Chemistry 73, 1372-1375. method of total saturated and total aromatics determination in oils and oil products by electron ionization mass spectrometry is presented. The contribution of saturated and aromatic hydrocarbons to the total ion current is found by solving a system of linear equations with coefficients that take stock a mutual interference of the mass spectra of saturated and aromatic hydrocarbons.Broek, T.A.B., Bour, A.L., Ianiri, H.L., Guilderson, T.P., McCarthy, M.D., 2019. Amino acid enantiomers in old and young dissolved organic matter: Implications for a microbial nitrogen pump. Geochimica et Cosmochimica Acta 247, 207-219. organic nitrogen (DON) represents the largest reservoir of fixed N in the surface ocean and a significant portion accumulates in the deep sea, where it can persist for millennial time scales. However, like the dissolved organic carbon (DOC) pool, the origin and composition of long-lived, refractory DON remains largely unknown. In recent years, the “microbial carbon pump” hypothesis has emerged from abundant evidence showing that microbial processes are primarily responsible for refractory DOC accumulation. However, a similar mechanism for DON has rarely been investigated. In the study of DON, spectroscopic evidence has indicated a primarily amide composition, implying a dominant contribution from peptides. Therefore, if an analogous “microbial nitrogen pump” controls refractory DON accumulation, the amino acid component should bear increasing signatures of microbial origin with increasing age. Here we investigate the microbial sequestration of N via the production of refractory DON, for the first time considering together DOM Δ14C with amino acid (AA) molar abundance (Mol%) and D/L ratio (as a tracer for prokaryotic input). Measurements were made on a unique set of high and low molecular weight (HMW, LMW) DOM isolates with 14C ages and chemical compositions generally consistent with semi-labile and refractory DOM respectively. The samples were collected in the North Pacific Subtropical Gyre where deep waters contain some of the oldest DOC in the world ocean. We observe higher D/L ratios in older, LMW DOM isolates for almost all analyzed AAs. Using mass spectral data, we also quantify three D-AAs in all samples (D-valine, D-phenylalanine, and D-leucine), which have not previously been confirmed in ocean DOM. These newly identified D-AAs are concentrated in the LMW refractory DOM fraction and have oceanographically consistent depth profiles. Our results suggest that several novel D-AA subgroupings may be unique tracers for different prokaryotic source processes. D-alanine appears to have largely independent cycling from the other D-AAs with a connection to the production of HMW DON, which we hypothesize is linked to water column peptidoglycan. In contrast, D-leucine, D-valine, and D-phenylalanine appear to be most strongly related to the production of LMW DON. Trends in both the HMW and LMW fractions suggest a linkage to sinking particles and local microbial transformations, implying that LMW DON has a direct biological source rather than originating from successive microbial reprocessing of HMW DON. Taken together, our observations are consistent with the dominant production of refractory LMW DON by prokaryotic organisms and suggests that different AA sub-groupings that can be used to track different processes within the DON pool.Broughton, J.M., Weitzel, E.M., 2018. Population reconstructions for humans and megafauna suggest mixed causes for North American Pleistocene extinctions. Nature Communications 9, Article 5441. of large mammals such as mammoth and mastodon disappeared in North America at the end of the Pleistocene with climate change and “overkill” by human hunters the most widely-argued causes. However, the population dynamics of humans and megafauna preceding extinctions have received little attention even though such information may be telling as we expect increasing human populations to be correlated with megafaunal declines if hunting caused extinctions. No such trends are expected if climate change was the primary cause. We present tests of these hypotheses here by using summed calibrated radiocarbon date distributions to reconstruct population levels of megafauna and humans. The results suggest that the causes for extinctions varied across taxa and by region. In three cases, extinctions appear linked to hunting, while in five others they are consistent with the ecological effects of climate change and in a final case, both hunting and climate change appear responsible.Brown, A., 2019. Origin of helium and nitrogen in the Panhandle–Hugoton field of Texas, Oklahoma, and Kansas, United States. American Association of Petroleum Geologists Bulletin 103, 369-403. and nitrogen variations in Panhandle–Hugoton field (PHF) gases are products of interaction between hydrocarbon gas from the Anadarko basin and at least two water masses with dissolved nitrogen and helium. The two most distinct water masses are from the Palo Duro basin (highest He/N2) and the Hugoton embayment (lowest He/N2). Geochemical data indicate several hundred million years of helium generation in porous rock. Helium migrated to the gas by diffusion through water-saturated rock and by west-to-east water flow.Sediment and basement helium generation and helium migration were modeled to validate timing and source of PHF helium. Models indicate a predominantly sedimentary helium source with some basement helium charge on the Amarillo uplift. Helium in the central and eastern PHF diffused from underlying rocks, whereas gases on the west and southwest sides were enriched in nitrogen and helium delivered by hydrodynamic water flow.Nitrogen in high-nitrogen gases was probably sourced as ammonium released from clays by cation exchange with brines derived from overlying salt units. The amount of mudrock (nitrogen and helium source) relative to other potential helium sources (arkose, radioactive dolomite) correlates to decreasing gas He/N2.The high helium concentrations in PHF gases result from multiple favorable circumstances. Old pore water accumulated dissolved helium during hundreds of millions of years of helium generation in sediment. High water/gas and low pressure favored higher helium concentrations in gas. Hydrodynamic flow delivered helium-rich pore water from basins west of the PHF.Bulat, S.A., Doronin, M.V., Pavlov, G.P., Karlov, D.S., Marie, D., Petit, J.-R., 2018. Unknown widespread iron- and sulfur-oxidizing bacteria beneath the East Antarctic ice sheet. Paleontological Journal 52, 1196-1203. analysis of the Vostok ice core (Central East Antarctica; one horizon, three boreholes) and D10 ice core (shoreline nearby the French Dumont d’Urville station) has reliably revealed three phylotypes (species) of aerobic iron-oxidizing betaproteobacteria of the family Gallionellaceae (closely related at the genus level to Sideroxydans lithotrophicus and Ferriphaselus amnicola), one of which has been detected from both the Vostok (borehole 5G-3) and D10 cores. In addition, the phylotype related to sulfur-oxidizing bacteria Tumebacillus sp. has been detected from both the Vostok (borehole 5G-2) and D10 cores. The both ice cores are almost equal in age, about 20?000 years; however, they differ in origin: the ice from Dumont d’Urville is atmospheric, while that from Vostok is a lake ice. The ice samples greatly vary in the storage time before treatment in the laboratory (from 0.5 to 40 years) and in intervals between treatments (from 1 to 5 years). The drilling sites are more than 1000 km apart. No evident hydrological links (the transfer of water beneath the ice sheet) between the Lake Vostok and Dumont D’Urville station have been found. This coincidence can be explained by the fact that minerals from the bedrock under the glacier, containing ferrous iron and reduced sulfur compounds, as well as physical and chemical conditions in both sites, liquid fresh water at a temperature near the freezing point, are similar. These and other assumptions are considered in the present article.Burke, K.D., Williams, J.W., Chandler, M.A., Haywood, A.M., Lunt, D.J., Otto-Bliesner, B.L., 2018. Pliocene and Eocene provide best analogs for near-future climates. Proceedings of the National Academy of Sciences 115, 13288-13293.: The expected departure of future climates from those experienced in human history challenges efforts to adapt. Possible analogs to climates from deep in Earth’s geological past have been suggested but not formally assessed. We compare climates of the coming decades with climates drawn from six geological and historical periods spanning the past 50 My. Our study suggests that climates like those of the Pliocene will prevail as soon as 2030 CE and persist under climate stabilization scenarios. Unmitigated scenarios of greenhouse gas emissions produce climates like those of the Eocene, which suggests that we are effectively rewinding the climate clock by approximately 50 My, reversing a multimillion year cooling trend in less than two centuries.Abstract: As the world warms due to rising greenhouse gas concentrations, the Earth system moves toward climate states without societal precedent, challenging adaptation. Past Earth system states offer possible model systems for the warming world of the coming decades. These include the climate states of the Early Eocene (ca. 50 Ma), the Mid-Pliocene (3.3–3.0 Ma), the Last Interglacial (129–116 ka), the Mid-Holocene (6 ka), preindustrial (ca. 1850 CE), and the 20th century. Here, we quantitatively assess the similarity of future projected climate states to these six geohistorical benchmarks using simulations from the Hadley Centre Coupled Model Version 3 (HadCM3), the Goddard Institute for Space Studies Model E2-R (GISS), and the Community Climate System Model, Versions 3 and 4 (CCSM) Earth system models. Under the Representative Concentration Pathway 8.5 (RCP8.5) emission scenario, by 2030 CE, future climates most closely resemble Mid-Pliocene climates, and by 2150 CE, they most closely resemble Eocene climates. Under RCP4.5, climate stabilizes at Pliocene-like conditions by 2040 CE. Pliocene-like and Eocene-like climates emerge first in continental interiors and then expand outward. Geologically novel climates are uncommon in RCP4.5 (<1%) but reach 8.7% of the globe under RCP8.5, characterized by high temperatures and precipitation. Hence, RCP4.5 is roughly equivalent to stabilizing at Pliocene-like climates, while unmitigated emission trajectories, such as RCP8.5, are similar to reversing millions of years of long-term cooling on the scale of a few human generations. Both the emergence of geologically novel climates and the rapid reversion to Eocene-like climates may be outside the range of evolutionary adaptive capacity.Buszewski, B., Walczak, J., Skoczylas, M., Haddad, P.R., 2019. High performance liquid chromatography as a molecular probe in quantitative structure-retention relationships studies of selected lipid classes on polar-embedded stationary phases. Journal of Chromatography A 1585, 105-112. on the retention mechanism of lipid classes (phospholipids, sphingomyelin) were performed using three polar-embedded stationary phases for which diol, phosphate, amino, and amide moieties were incorporated into the alkyl chains of the stationary phases. Their structural descriptors were determined using the quantum-mechanical method. The retention behavior of the analytes was investigated as a function of different binary hydro-organic mobile phases containing (90%/10% acetonitrile (or methanol)/0.1% formic acid). It was found that the elution order on the tested stationary phases was governed chiefly by the hydrophilicity of the analyte and indicated the existence of a hydrophilic interaction liquid chromatography retention mechanism. Quantitative structure-retention relationships studies were performed to further elucidate the retention mechanism. These studies showed that the dominant analyte descriptor influencing retention on the alkyl-amine stationary phase was the logarithm of the octanol-water partition coefficient. For the phospho-diol and alkyl-amide stationary phases, the dominant analyte descriptor influencing retention was the molar volume and solvent accessible area of the analyte, respectively.Call, M., Santos, I.R., Dittmar, T., de Rezende, C.E., Asp, N.E., Maher, D.T., 2019. High pore-water derived CO2 and CH4 emissions from a macro-tidal mangrove creek in the Amazon region. Geochimica et Cosmochimica Acta 247, 106-120. paper presents the first aquatic CO2 and CH4 flux estimates from a macro-tidal mangrove creek located in the 0–5° latitude band, where ～30% of the world’s mangroves occur. High resolution dissolved CO2, CH4 and 222Rn (a natural pore-water tracer) concentrations were measured over a spring-neap tidal cycle from a mangrove tidal creek located in North Brazil (～0.8°S). Surface water pCO2, CH4 and 222Rn ranged from 592 to 15,361 μatm, 58 to 1469?nM, and 585 to 16,583 dpm m?3 with considerable temporal variability observed semi diurnally (i.e. hourly) and over the spring-neap cycle (i.e. weekly). Tidally-driven pore-water exchange (tidal pumping) drove surface water pCO2 and CH4, leading to high concentrations at low-tide (semi-diurnal variability). Higher pCO2 and CH4 were also observed after the inundation of the upper inter-tidal flat, with peak values coinciding with the “first flush” of aged pore-waters. We hypothesise that additional pore-water exchanges occur during forest inundation in macro-tidal mangrove systems, controlling mangrove creek water pCO2 and CH4 over spring-neap cycles. Estimated CO2 and CH4 water-atmosphere fluxes were 174?±?129?mmol?m?2?d?1 and 855?±?406?μmol?m?2?d?1, respectively. These emissions are amongst the highest reported for mangrove systems worldwide and suggests that the most recent global estimates based mostly on data from higher latitudes may have underestimated the role of mangroves in greenhouse gas emissions.Cao, H., Kaufman, A.J., Shan, X., 2019. Coupled isotopic evidence for elevated pCO2 and nitrogen limitation across the Santonian-Campanian transition. Chemical Geology 504, 136-150. Santonian–Campanian (S–C) transition notably coincides with the termination of the Cretaceous Normal Superchron, a positive carbon isotope anomaly, and the enhanced preservation of organic matter associated with an oceanic anoxic event at ca. 84?Ma. The driving factors for the OAEs should include global warming, widely believed to be from volcanic sources, the delivery of nutrients to surface oceans from the continents, anoxic sediments and atmosphere, and variations in the configuration of ocean basins. To further investigate this phenomenon and evaluate whether there was a teleconnection between the marine and continental realm, we have studied a lacustrine succession in northeastern China (the Songliao Basin, which is ~3× the size of Lake Superior) that preserves two thick horizons of oil shales and a positive carbon isotope anomaly recorded in ostracode carbonate near the S–C boundary. This freshwater basin is one of the many that formed as a consequence of Mesozoic extensional tectonics in eastern Asia. The stratigraphic trends illustrate broad excursions in the isotopic compositions of carbonate, total organic carbon (including black carbon), and total nitrogen. The carbon isotope data suggest that maximal fractionation (εTOC) at the S–C boundary is caused by enhanced burial of organic carbon and inputs from anoxygenic photoautotrophs and chemoautotrophs, or from the buildup of CO2 in a lake environment. On the other hand, the nitrogen isotope data suggest that the lake became limited in nitrogen immediately before the deposition of the younger oil shale, resulting in the addition of new nitrogen to the system, likely as the result of diazotrophy or ammonium assimilation. To some extent, all of the features we described from the Songliao Basin have been recognized in Jurassic and Cretaceous OAEs. Insofar as climatically-sensitive lakes are typically supersaturated with CO2 relative to the atmosphere, we speculate that nutrient-driven primary productivity in massive lake systems may have released enough greenhouse gas (CO2, CH4, and N2O) into the atmosphere and therefore played a role in enhancing global temperatures and driving widespread anoxia in the Mesozoic oceans.Cao, W., Williams, S., Flament, N., Zahirovic, S., Scotese, C., Müller, R.D., 2018. Palaeolatitudinal distribution of lithologic indicators of climate in a palaeogeographic framework. Geological Magazine 156, 331-354. the latitudinal distribution of climate-sensitive lithologies is stable through greenhouse and icehouse regimes remains unclear. Previous studies suggest that the palaeolatitudinal distribution of palaeoclimate indicators, including coals, evaporites, reefs and carbonates, has remained broadly similar since the Permian period, leading to the conclusion that atmospheric and oceanic circulation control their distribution rather than the latitudinal temperature gradient. Here we revisit a global-scale compilation of lithologic indicators of climate, including coals, evaporites and glacial deposits, back to the Devonian period. We test the sensitivity of their latitudinal distributions to the uneven distribution of continental areas through time and to global tectonic models, correct the latitudinal distributions of lithologies for sampling- and continental area-bias, and use statistical methods to fit these distributions with probability density functions and estimate their high-density latitudinal ranges with 50% and 95% confidence intervals. The results suggest that the palaeolatitudinal distributions of lithologies have changed through deep geological time, notably a pronounced poleward shift in the distribution of coals at the beginning of the Permian. The distribution of evaporites indicates a clearly bimodal distribution over the past ~400 Ma, except for Early Devonian, Early Carboniferous, the earliest Permian and Middle and Late Jurassic times. We discuss how the patterns indicated by these lithologies change through time in response to plate motion, orography, evolution and greenhouse/icehouse conditions. This study highlights that combining tectonic reconstructions with a comprehensive lithologic database and novel data analysis approaches provide insights into the nature and causes of shifting climatic zones through deep time.Carbognani Ortega, L.A., 2018. Plausible locus for large paraffinic compounds in the Boduszynski continuous composition petroleum model, in: Ovalles, C., Moir, M.E. (Eds.), The Boduszynski Continuum: Contributions to the Understanding of the Molecular Composition of Petroleum. American Chemical Society, pp. 173-187. presenting evidence on the existence of petroleum large molecular weight paraffinic compounds spanning the C90-C215 carbon atoms is reviewed. The use of conventional handling and characterization techniques of the oil samples could lead to inadequate or misleading information. High temperature liquid chromatography isolation and characterization techniques and the use of soft ionization mass spectrometry techniques were shown mandatory for their analysis. Both positive and negative properties over petroleum fractions provided by such hydrocarbons were identified. A plausible locus within the Boduszynski continuous molecular composition petroleum model is advanced.Carbognani Ortega, L.A., Carbognani, J., Almao, P.P., 2018. Correlation of thermogravimetry and high temperature simulated distillation for oil analysis: Thermal cracking influence over both methodologies, in: Ovalles, C., Moir, M.E. (Eds.), The Boduszynski Continuum: Contributions to the Understanding of the Molecular Composition of Petroleum. American Chemical Society, pp. 223-239. presenting evidence on the existence of Thermal Cracking affecting both Thermogravimetric Analysis and High Temperature Simulated Distillation is reviewed. Thermal cracking phenomena were observed to appear as soon as the instruments reached known temperatures able to induce molecules scission (350-370?C). Distillation temperatures reported beyond 550?C Atmospheric Equivalent Boiling Point were determined to be unreliable from thermal cracking effects. Thorough understanding of the parameters governing both studied distillation techniques, allowed to propose equations for converting Thermogravimetric data into Simulated Distillation results. Percent relative errors derived from such conversion were determined to span the ±10 range.Carlson, P.E., Banner, J.L., Johnson, K.R., Casteel, R.C., Breecker, D.O., 2019. Carbon cycling of subsurface organic matter recorded in speleothem 14C records: Maximizing bomb-peak model fidelity. Geochimica et Cosmochimica Acta 246, 436-449. 1955 to 1963, atmospheric testing of nuclear weapons caused a significant rise in atmospheric radiocarbon activity. This “bomb peak” has been used to calculate turnover rates of organic carbon in soils and other recent sedimentary deposits. Some speleothems contain precise and independently dated records of radiocarbon activity. These records can be used to understand, through inverse modeling, the processes and rates of turnover of subsurface organic carbon in karst regions. This approach is complicated, however, by the contribution of radioactively “dead” carbon to the stalagmite by the dissolution of host-rock limestone and/or by the respiration of relatively old soil organic matter. Previously published inverse models of the radiocarbon bomb peak in speleothems constrain the dead carbon proportion (DCP, in percent) by comparing measurements of speleothem radiocarbon activity from before the onset of the bomb peak to measurements of coeval atmospheric radiocarbon. This approach precludes modeling of speleothems that began growing after the onset of atmospheric nuclear weapons testing in 1955. Here, we advance the inverse modeling framework to calculate DCP using the entire length of the speleothem record, allowing for the modeling of speleothems that began growing after the initiation of atmospheric nuclear weapons testing. We test the sensitivity and resolution of this model and find that it can precisely resolve the turnover times and relative contributions of subsurface organic matter pools with residence times of less than a decade. The model fails to resolve turnover times or relative contributions of organic matter pools on millennial or greater timescales. These results also hold for the previously published models from which the current model is derived. We find that imprecise estimates of slow-turnover carbon add significant uncertainty to the calculated average age of respired carbon, which is a common metric of subsurface carbon cycling. The high precision and resolution attainable between sub-decadal carbon pools will allow researchers to differentiate the (sub-)annual pool, which is likely dominated by root/rhizosphere respiration, from the 2- to 10-year pools, which are likely dominated by microbial decomposition of labile organic carbon. The high precision attainable in fast-turnover pools also suggests that when there are multiple viable chronological interpretations for the same speleothem, bomb peak models could be used to help select which chronology is most likely to be accurate. This is important for high-resolution (sub-annual) speleothem climate records, where even single-year chronological offsets can result in misleading calibrations to the instrumental record.Castillo, J., de Klerk, A., 2019. Visbreaking of deasphalted oil from bitumen at 280–400 °C. Energy & Fuels 33, 159-175. time-dependent thermal conversion of vacuum residue deasphalted oil was studied at 280, 320, 360, and 400 °C. The vacuum residue deasphalted oil was an industrial product produced by vacuum distillation of Athabasca bitumen followed by solvent deasphalting using n-pentane. This type of visbreaking process was of interest for partial upgrading of bitumen to facilitate pipeline transport. Practically useful cracking conversion and viscosity reduction for upgrading were found only at 360 and 400 °C. The viscosity measured at 40 °C could be reduced by 3 orders of magnitude from 3720 Pa s in the feed to 2–5 Pa s in the product. The density of the product was not reduced by much, despite vacuum residue cracking conversions of 34% at 360 °C and 45–47% at 400 °C before the onset of coking. The liquid yield was 88–89%. A heavier product fraction was formed during thermal conversion. The heavy material was not necessarily asphaltenes, but an increase in n-pentane-insoluble material was also found that appeared correlated with the aromatic hydrogen content of the product. The limited change in density was at least partly explained by the increase in both heavy material and aromatic nature of the product. Vacuum residue conversion at 360 °C increased linearly with time, which indicated zero-order kinetics. Vacuum residue conversion at 400 °C was non-zero-order. This study showed that thermal cracking at 360–400 °C is better described by a rate equation with two terms. Temperature-dependent differences in the maximum conversion before the onset of coking and the kinetic description of vacuum residue conversion indicated that the equivalent residence time description of visbreaking was an inadequate approximation of thermal conversion at 400 °C and below.Castro-Morales, K., Schürmann, G., K?stler, C., R?denbeck, C., Heimann, M., Zaehle, S., 2019. Three decades of simulated global terrestrial carbon fluxes from a data assimilation system confronted to different periods of observations. Biogeosciences Discussions 2019, 1-43. paper presents global land carbon fluxes for the period 1982–2010 (gross primary production, GPP, and net ecosystem exchange, NEE) estimated with the Max Planck Institute – Carbon Cycle Data Assimilation System (MPI-CCDAS v1). The primary aim of this work is to analyze the performance of the MPI-CCDAS when it is confronted with three different time periods for data assimilation (DA), and thereby to assess its prognostic capability. To this extend we assimilated nearly three decades (1982–2010) of space borne measurements of the fraction of absorbed photosynthetic active radiation (FAPAR) and atmospheric CO2 concentrations from the global network of flask and in situ measurements. Both data sets were incorporated with different assimilation windows covering the periods 1982–1990, 1990–2000 and 1982–2010. The assimilation results show a considerable improvement in the long-term trend and seasonality of FAPAR in the Northern Hemisphere, as well as in the long term trend and seasonal amplitude of the atmospheric CO2 concentrations when compared to the observations in sites globally distributed. After the assimilation, the global net land-atmosphere CO2 exchange (NEE) was ?1.2PgCyr?1, in agreement with independent estimates, while gross primary production (GPP; 92.5PgCyr?1) was somewhat below the magnitude of independent estimates. The NEE in boreal eastern regions (Northeast Asia) increased on average by ?0.13PgCyr?1, which translated into an intensification of the carbon uptake in those regions by nearly 30% than the contribution to the global annual average in the model before the assimilation. Our results demonstrate that using information only over a decade already yielded a large fraction of the overall model improvement, in particular for the simulation of phenological seasonality, its interannual variability (IAV) and long-term trend. Adding longer than decadal data did only lead to very moderate improvements in the long-term trend of the FAPAR simulated by the model, which may be attributed to the small model-data mismatch at the long timescales compared to the significantly larger observational signal and model-data mismatch error at seasonal cycle time scale. Decadal data also significantly improved the seasonality, IAV and long-term simulated trend in atmospheric CO2. Importantly, when running the MPI-CCDAS v1 with 30 years of data, the results remained in line with observations throughout this period, suggesting that the model can represent land uptake to a sufficient degree to make it compatible with the atmospheric CO2 record. Using data from 1982 to 1990 in the assimilation yielded only a difference to the observations of 2±1.3ppm for the period 15 to 19 years after the end of the assimilation. This suggests that despite imperfections in the representation of IAV, model-data fusion can increase the prognostic capacity of land carbon cycle models at relevant time-scales.Ceci, A., Pinzari, F., Russo, F., Persiani, A.M., Gadd, G.M., 2019. Roles of saprotrophic fungi in biodegradation or transformation of organic and inorganic pollutants in co-contaminated sites. Applied Microbiology and Biotechnology 103, 53-68. decades, human activities, industrialization, and agriculture have contaminated soils and water with several compounds, including potentially toxic metals and organic persistent xenobiotics. The co-occurrence of those toxicants poses challenging environmental problems, as complicated chemical interactions and synergies can arise and lead to severe and toxic effects on organisms. The use of fungi, alone or with bacteria, for bioremediation purposes is a growing biotechnology with high potential in terms of cost-effectiveness, an environmental-friendly perspective and feasibility, and often representing a sustainable nature-based solution. This paper reviews different ecological, metabolic, and physiological aspects involved in fungal bioremediation of co-contaminated soils and water systems, not only addressing best methods and approaches to assess the simultaneous presence of metals and organic toxic compounds and their consequences on provided ecosystem services but also the interactions between fungi and bacteria, in order to suggest further study directions in this field.Chacón-Pati?o, M.L., Rowland, S.M., Rodgers, R.P., 2018. The compositional and structural continuum of petroleum from light distillates to asphaltenes: The Boduszynski Continuum Theory as revealedby FT-ICR mass spectrometry, in: Ovalles, C., Moir, M.E. (Eds.), The Boduszynski Continuum: Contributions to the Understanding of the Molecular Composition of Petroleum. American Chemical Society, pp. 113-171. years ago, Boduszynski published the first part in a series of manuscripts that addressed the composition, and compositional progression of heavy oil. It concluded that crude oil composition increases gradually and continuously in aromaticity, molecular weight, and heteroatom content as a function of boiling point. Remarkably, the Continuum Model was inferred from field ionization mass spectral data that lacked the requisite resolution to uniquely identify elemental compositions across the observed mass range. However, combined with boiling point trends of light distillate classes, molecular weight distributions, boiling point cuts, and chromatography, Boduszynski assembled a series of manuscripts that described the Continuum Model of Petroleum. Herein, we revisit the same topic and employ the same analytical methods, only now armed with state-of-the-art Fourier Transform Ion Cyclotron Resonance Mass Spectrometers (FT-ICR MS) that can readily resolve and uniquely identify molecular formulas to tens-of-thousands of individual petroleum species in a single analysis. We tested the Continuum Model for hundreds-of-thousands of species identified by mass spectrometry, from light distillates to asphaltenes, and found no deviations. In the process, we collected data that supports the low molecular weight of petroleum (< 2000 Da), defines the maltene continuum, highlights the effect of aggregation on mass spectral analysis, identifies and overcomes selective ionization, and confirms that asphaltenes are composed of abundant island and archipelago structures. In this chapter, we review FT-ICR MS petroleum characterization efforts that led to the conclusion that the Boduszynski Continuum Model is correct and thus applicable to both the compositional and structural continuum of petroleum.Chan, Q.H.S., Nakato, A., Kebukawa, Y., Zolensky, M.E., Nakamura, T., Maisano, J.A., Colbert, M.W., Martinez, J.E., Kilcoyne, A.L.D., Suga, H., Takahashi, Y., Takeichi, Y., Mase, K., Wright, I.P., 2019. Heating experiments of the Tagish Lake meteorite: Investigation of the effects of short-term heating on chondritic organics. Meteoritics & Planetary Science 54, 104-125. present in this study the effects of short‐term heating on organics in the Tagish Lake meteorite and how the difference in the heating conditions can modify the organic matter (OM) in a way that complicates the interpretation of a parent body's heating extent with common cosmothermometers. The kinetics of short‐term heating and its influence on the organic structure are not well understood, and any study of OM is further complicated by the complex alteration processes of the thermally metamorphosed carbonaceous chondrites—potential analogues of the target asteroid Ryugu of the Hayabusa2 mission—which had experienced posthydration, short‐duration local heating. In an attempt to understand the effects of short‐term heating on chondritic OM, we investigated the change in the OM contents of the experimentally heated Tagish Lake meteorite samples using Raman spectroscopy, scanning transmission X‐ray microscopy utilizing X‐ray absorption near edge structure spectroscopy, and ultraperformance liquid chromatography fluorescence detection and quadrupole time of flight hybrid mass spectrometry. Our experiment suggests that graphitization of OM did not take place despite the samples being heated to 900 °C for 96 h, as the OM maturity trend was influenced by the heating conditions, kinetics, and the nature of the OM precursor, such as the presence of abundant oxygenated moieties. Although both the intensity of the 1s?σ* exciton cannot be used to accurately interpret the peak metamorphic temperature of the experimentally heated Tagish Lake sample, the Raman graphite band widths of the heated products significantly differ from that of chondritic OM modified by long‐term internal heating.Chen, Q., Yan, X., Guo, Y., Hong, T., Nie, H., Zhang, J., Tang, X., Li, W., Liu, C., 2018. Geochemistry, petrology and mineralogy of coal measure shales in the Middle Jurassic Yanan Formation from northeastern Ordos Basin, China: Implications for shale gas accumulation. Acta Geologica Sinica - English Edition 92, 2333-2350. Jurassic Yanan Formation is one of the most important coal‐producing formations and hydrocarbon source rocks in the Ordos Basin, North China. To evaluate the shale gas potential of the Yanan shale, a total of 48 samples from north Ordos Basin were sampled, and their geochemical, petrological, mineralogical and pore characteristics were investigated. It was found that the shale samples are a suite of early mature source rock. The total organic carbon (TOC) content ranges from 0.33% to 24.12% and the hydrogen index (HI) ranges from 43.31mg/g to 330.58 mg/g. The relationship between Tmax and HI indicates the organic matter is type II‐III. This conclusion is also supported by the organic petrological examination results, which shows that the kerogen is mainly liptinite and vitrinite. Minerals in the samples are composed mainly of quartz, clay and feldspar, and the clay minerals are composed of prevailing kaolinite, illite/smectite, chlorite and a small amount of illite. Under scanning electron microscope, OM pores in the Yanan shale are scarce except pores come from the kerogen intrinsic texture or clay aggregates within the organic particles. As the weak compaction caused by shallow burial depth, interparticle pores and intraparticle pores are common, the hydrocarbon storage capacity of the Yanan shale was improved. According to evaluation, the Yanan shale is considered as a good shale gas reservoir, but its hydrocarbon potential is more dependent on biogenic and coal‐derived gas as the thermogenic gas is limited by the lower thermal maturity.Chen, R., Zhang, P., Qin, Y., Wei, C., Wang, L., 2018. New discovery on methane adsorption change of coal due to Sc-CO2 extraction during CO2-ECBM. Acta Geologica Sinica - English Edition 92, 2438-2439. abstractChen, Y.-F., Zong, Z.-M., Li, X.-K., Liu, G.-H., Yang, Z., Jiang, X.-G., Liu, F.-J., Wei, X.-Y., Guo, Q.-J., Zhao, T.-S., Bai, H.-C., Wang, B.-J., 2018. An effective approach for separating carbazole and its derivates from coal-tar-derived anthracene oil using ionic liquids. Energy & Fuels 33, 513–522. and its derivates are important value-added chemicals (VACs) in anthracene oil (AO), which is one of the coal tar fractions. In this work, imidazolium-based ionic liquids (ILs) were used as novel extractants to extract carbazole from AO and the effects of anionic substituents and cationic structures on carbazole extraction were investigated. The results show that the recovery and purity of carbazole reached up to 96.2 and 98.0%, respectively, by extracting AO-related model oil with the ILs. The hydrogen-bond force existing between 1-butyl-3-methylimidazolium dicyanamide (ILa) and carbazole was revealed by Fourier transform infrared spectroscopy and two-dimensional nuclear magnetic resonance and further confirmed by density functional theory simulation. π–π interactions and hydrogen bonds formed between ILs and carbazole play crucial roles in effectively separating carbazole from AO. Simultaneously, the stability test shows that ILa is easily recyclable and highly stable for carbazole separation. Moreover, the recovery and purity of carbazole extracted from AO are 66.6 and 90.2%, respectively, with ILa as the extractant by flash chromatography. This study provides a green and effective approach for separating VACs from coal tar and its derived fractions.Chen, Y., Zhu, Z., Zhang, L., 2019. Control actions of sedimentary environments and sedimentation rates on lacustrine oil shale distribution, an example of the oil shale in the Upper Triassic Yanchang Formation, southeastern Ordos Basin (NW China). Marine and Petroleum Geology 102, 508-520. shale is an important form of unconventional resources. It is significant to determine the control factors on oil shale distribution. Abundant oil shale resources are hosted in the Member Chang 7–3 (Ch7-3), Triassic Yanchang Formation in southeastern Ordos Basin (NW China). This study was conducted to investigate the sedimentary environment, distribution and organic matter source of the Ch7-3 Oil shale by a combined study of outcrops, core data, organic and element geochemical indices. The controlling factors of the oil shale distribution were determined by an analysis of sedimentary environments and geochemical features of the oil shale. Sedimentary facies analysis based on outcrops and core data indicated that the Ch7-3 Oil shale was deposited in lacustrine-delta environments. Warm and moist climates and reducing conditions indicated by major and trace elements were favorable to organic matter production and preservation. Rock-Eval pyrolysis showed that the organic matter of the Ch7-3 Oil shale is from both lacustrine phytoplankton and terrigenous higher plants. The organic matter from terrigenous higher plants was probably transported into the deep lake by gravity flows. Sedimentary facies and (La/Yb)N values show that the spatial distribution of oil shale was controlled by sedimentary environments and sedimentation rates. In the deep lake area near to delta-turbidite fan deposition systems, terrestial organic matter input was bounteous, and sedimentation rates were moderate, which were beneficial to organic matter accumulation and preservation, providing favorable conditions for oil shale formation. In delta-turbidite fan deposition systems, high sedimentation rates led to organic matter dilution. In the deep lake area far from delta-turbidite fan deposition systems, sedimentation rates were relatively low, and organic matter was easily degraded, in addition only lacustrine organic matter input with no terrestial organic matter input inhibited organic matter enrichment.Cheng, S.-C., Bhat, S.M., Lee, C.-W., Shiea, J., 2019. Simple interface for scanning chemical compounds on developed thin layer chromatography plates using electrospray ionization mass spectrometry. Analytica Chimica Acta 1049, 1-9. simple and cheap design for interfacing thin layer chromatography (TLC) with electrospray ionization mass spectrometry (ESI/MS) was developed to scan and characterize compounds on TLC plate. The developed TLC plate was rapidly and easily modified into two sawtooth-edged pieces that were positioned on an XYZ stage so that one of the triangular tips was pointed toward the MS inlet. A drop of methanol and high DC voltage was applied at the tip to induce ESI. After the analytes in the first tip were analyzed, the TLC piece was moved so that the second triangular tip was pointed toward the MS inlet for analysis. The process was repeated until all the triangular tips on the piece were analyzed. In this manner, the analytes, no matter visible or non-visible bands, were scanned and characterized. Since a 4.8?cm long TLC track were cut to 32 triangles on two sawtooth pieces for analysis, the spatial resolution of using the sawtooth TLC-ESI/MS for analysis is 1.5 mm/band. A mixture of dye standards and Datura metel flower extract was analyzed to demonstrate the capability of sawtooth TLC-ESI/MS on scanning and characterizing chemical compounds on the TLC plates. The limits of detection of the dye standards were between 0.25 and 2.5 ng/band. TLC bands containing alkaloids such as scopolamine and norscopolamine from the Datura metel flower extract were not visualized on the developed TLC track, but were successfully detected at different triangular tips using sawtooth TLC-ESI/MS. Based on these results, the Rf values of scopolamine and norscopolamine were determined.Cheptsov, V.S., Vorobyova, E.A., Gorlenko, M.V., Manucharova, N.A., Pavlov, A.K., Lomasov, V.N., 2018. Effect of gamma radiation on viability of a soil microbial community under conditions of Mars. Paleontological Journal 52, 1217-1223. is supposed that the biosphere could be formed under conditions of early Mars, and it is cryo-conserved up to now. The period of its preservation is limited by the effect of ionizing radiation. The viability of a soil microbial community thtat underwent gamma radiation (100 kGy) under simulated conditions (?50°C, 1 Torr) of the surface layer of the Martian regolith is studied. Irradiation did not result in the death of the microbial community: the number of living cells, metabolic activity, and functional diversity remained high. The data obtained suggest that microorganisms could be preserved in regolith of Mars for no less than 1.3 m.y. and in general contribute to the modern concepts concerning radiation resistance of the Earth’s life?form.Coch, C., Juhls, B., Lamoureux, S.F., Lafrenière, M., Fritz, M., Heim, B., Lantuit, H., 2019. Characterizing organic matter composition in small Low and High Arctic catchments using terrestrial colored dissolved organic matter (cDOM). Biogeosciences Discussions 2019, 1-30. change is an important control of carbon cycling, particularly in the Arctic. Permafrost degradation through deeper thaw and physical disturbances result in the release of carbon dioxide and methane to the atmosphere and to an increase in riverine dissolved organic matter (DOM) fluxes. Whereas riverine DOM fluxes of the large Arctic rivers are well assessed, knowledge is limited with regard to small catchments that cover more than 40% of the Arctic drainage basin. Here, we use absorption measurements to characterize changes in DOM quantity and quality in a Low Arctic (Herschel Island, Yukon, Canada) and a High Arctic (Cape Bounty, Melville Island, Nunavut, Canada) setting with regard to geographical differences, impacts of permafrost degradation and rainfall events. We find that DOM quantity and quality is controlled by differences in vegetation cover and soil organic carbon content. The Low Arctic site has higher SOCC and greater abundance of plant material introducing higher lignin concentrations into the aquatic system and resulting in a stronger color of DOM than in the High Arctic. There is a strong relationship between dissolved organic carbon (DOC) concentration and absorption characteristics (cDOM) for surface waters at both sites similar to the one for the great Arctic rivers. We used the optical characteristics of DOM such as cDOM absorption, Specific UltraViolet Absorbance SUVA, UltraViolet UV Slope, Slope Ratio for assessing quality changes downstream, at baseflow and stormflow conditions and in relation to permafrost disturbance. DOM in streams at both sites demonstrated optical signatures indicative of photodegradation downstream processes, even over short distances of 2000m. It was determined that flow pathways and the connected hydrological residence time control DOM quality. Deeper flow pathways allow the export of permafrost-derived DOM, whereas shallow pathways with shorter residence times lead to the export of fresh near-surface derived DOM. Compared to the large Arctic rivers, DOM quality exported from the small catchments studied here is much fresher and therefore prone to degradation. This work shows that optical properties of DOM will be a useful tool for understanding DOM sources and quality at a pan-Arctic scale.Cocovi-Solberg, D.J., Rosende, M., Michalec, M., Miró, M., 2019. 3D printing: The second dawn of lab-on-valve fluidic platforms for automatic (bio)chemical assays. Analytical Chemistry 90, 1140-1149. this work, inexpensive manufacturing of unibody transparent mesofluidic platforms for pressure-driven Lab-On-a-Valve (LOV) methodologies is accomplished via rapid one-step 3D prototyping from digital models by user-friendly freeware. Multichannel architecture having 800–1800 μm cross-sectional features with unconventional 3D conduit structures and integrating optical and electrochemical detection facilities is for the first time reported. User-defined flow-programming capitalizing upon software control for automatic liquid handling is synergistically combined with additive manufacturing based on stereolithographic 3D printing so as to launch the so-called fourth generation of microflow analysis (3D-μFIA). Using an affordable consumer-grade 3D printer dedicated LOV platforms are 3D printed at will and prints are characterized in terms of solvent compatibility, optical and mechanical properties, and sorption of inorganic and organic species to prospect potentialities for the unfettered choice of chemistries. The unique versatility of the 3D-printed LOV device that is attached to a multiposition rotary valve as a central design unit is demonstrated by (i) online handling of biological materials followed by on-chip photometric detection, (ii) flow-through bioaccessibility tests in exposome studies of contaminated soils with miniaturized voltammetric detection, (iii) online phospholipid removal by TiO2-incorporated microextraction approaches using on-chip disposable sorbents, and (iv) automatic dynamic permeation tests mimicking transdermal measurements in Franz-cell configurations. A multipurpose LOV fluidic platform can be fabricated for less than 11 Euros.Colonnella, M.A., Lizarraga, L., Rossi, L., Díaz Pe?a, R., Egoburo, D., López, N.I., Iustman, L.J.R., 2019. Effect of copper on diesel degradation in Pseudomonas extremaustralis. Extremophiles 23, 91-99. co-contaminated with heavy metals and hydrocarbons have become an important problem worldwide, especially due to the effect of metals on hydrocarbon degrading microorganisms. Pseudomonas extremaustralis, a bacterium isolated from a pristine pond in Antarctica, showed high capabilities to cope with environmental stress and a very versatile metabolism that includes alkane degradation under microaerobic conditions. In this work, we analyzed P. extremaustralis’ capability to resist high copper concentrations and the effect of copper presence in diesel biodegradation. We observed that P. extremaustralis resisted up to 4?mM CuSO4 in a rich medium such as LB. This copper resistance is sustained by the presence of the cus and cop operons together with other efflux systems and porins located in a single region in P. extremaustralis genome. When copper was present, diesel degradation was negatively affected, even though copper enhanced bacterial attachment to hydrocarbons. However, when a small amount of glucose (0.05% w/v) was added, the presence of CuSO4 enhanced alkane degradation. In addition, atomic force microscopy analysis showed that the presence of glucose decreased the negative effects produced by copper and diesel on the cell stock, K., Ma, S., Sharma, S., Chen, Y., Ding, C., 2019. Enhanced metabolite identification using Orbitrap tribrid mass spectrometer. Drug Metabolism and Pharmacokinetics 34, S32-S33.: High resolution mass spectrometry (HRMS) is an essential tool for metabolite identification. HRMS with sophisticated data acquisition features can provide the critical information for metabolite structure elucidation and alleviate the difficulties of matrix complexity. Here we present a study for metabolite ID using Orbitrap Tribrid MS with data acquisition features designed to significantly improve small molecule structure analysis, which include automatic background ions subtraction, inclusion/exclusion lists generation, and real-time decision-making to optimize MSn data acquisition quality and speed. The high quality information-rich MSn data generated using this improved HRMS was processed using structure analysis and data mining software "Mass Frontier" and "Compound Discoverer".Method: Amprenavir, Bosentan, Lopinavir, and Ritonavir were selected as model compounds. The compounds, at concentration of (5 μM), were incubated with human liver microsomes (HLM) in the presence of GSH and UDPGA. Incubations without drug or without NADPH were chosen purposely to test the background subtraction feature. The LCMS analyses were performed on Vanquish Flex Binary UPLC system with DAD detector coupled to an Orbitrap Tribrid Mass Spectrometer. Mobile phases were composed of: A: H2O/0.1% formic acid, and B: ACN/0.1% formic acid with gradient on Hypersil column (2.1X100 mm 1.9 μm). High resolution full scan and MSn data were collected in a data-dependent fashion with polarity switching. The data acquisition method was incorporated with features optimized for small molecule analysis.Preliminary Data: These HIV drugs were selected because of their extensive metabolism. Using the Orbitrap Tribrid Mass Spectrometer's special features for small molecule data acquisition: the automatic background subtraction, inclusion/exclusion list generation, and real-time decision-making optimization of MSn spectra acquisition, the MS provides a wealth of information for metabolite identification. The automatic background subtraction feature is especially useful for identification of metabolites present in a complicated biologic matrix. The new and enhanced features that use the high quality MS/MS fragments to trigger the MSn acquisition significantly improved MSn data quality, because multi-stage MS/MS (MSn) information is essential for confident metabolite structure elucidation. For example, HRAM full scan data show that Ritonavir metabolites include four mono-oxidation products, two N-dealkylation products, and four di-oxidation products. In order to determine the structure and the sites of biotransformation of these metabolites, high quality MS/MS and higher order MS/MS spectra were obtained using the novel data collection features of Orbitrap Tribrid MS. Major and minor metabolites, both phase I and II, of these model compounds formed in the HLM microsomal incubations were quickly detected by processing the HRAM and higher level MS/MS (MSn) spectra of metabolites using Mass Frontier and Compound Discoverer. This workflow offers significant improvements in speed and confidence of routine drug metabolite identification and other small molecule structure characterization applications. Conclusion: Small molecule specific acquisition features of Orbitrap Tribrid MS improve MSn data quality and increase confidence for metabolite identification.Coogan, L.A., Da?ron, M., Gillis, K.M., 2019. Seafloor weathering and the oxygen isotope ratio in seawater: Insight from whole-rock δ18O and carbonate δ18O and Δ47 from the Troodos ophiolite. Earth and Planetary Science Letters 508, 41-50. controls on, and history of, the oxygen isotope ratio in seawater continue to be debated after many decades of research with the lack of consensus in large part reflecting uncertainty in the role of hydrothermal exchange between seawater and the oceanic crust. We have investigated this using new carbonate Δ47 and δ18O data, and whole-rock O-isotope data, for samples from the lava section of the Troodos ophiolite. Carbonate data confirm that fluid-to-rock ratios in the upper lavas during off-axis hydrothermal circulation are generally sufficiently large that both the fluid δ18O and temperature are similar to those of bottom water. However, some samples require more complicated interpretations that could reflect changes in the rate of calcite formation. Whole-rock data indicate that O-isotope exchange in the lavas is directly linked to the major element exchange that leads to alkalinity production (i.e., CO2 consumption) and both are dependent on bottom water temperature. This means that the O-isotopic composition of seawater is linked to the long-term C-cycle. The data are used to parameterise a simple model of the evolution of the O-isotopic composition of seawater driven by changes in solid earth CO2 degassing. Alkalinity balance links the total extent of weathering of the continents and seafloor, which are sinks for high δ18O material, to CO2 degassing rate and surface temperature. The modelling suggests that if solid earth CO2 degassing and the rate of formation of oceanic crust are linked, the O-isotopic composition of the ocean (including any ice sheets) is unlikely to have varied more than ±1‰ over the Phanerozoic.Cook, E.C., Featherston, E.R., Showalter, S.A., Cotruvo, J.A., 2019. Structural basis for rare earth element recognition by Methylobacterium extorquens lanmodulin. Biochemistry 58, 120-125. (LanM) is a high-affinity lanthanide (Ln)-binding protein recently identified in Methylobacterium extorquens, a bacterium that requires Lns for the function of at least two enzymes. LanM possesses four EF-hands, metal coordination motifs generally associated with CaII binding, but it undergoes a metal-dependent conformational change with a 100 million-fold selectivity for LnIIIs and YIII over CaII. Here we present the nuclear magnetic resonance solution structure of LanM complexed with YIII. This structure reveals that LanM features an unusual fusion of adjacent EF-hands, resulting in a compact fold to the best of our knowledge unique among EF-hand-containing proteins. It also supports the importance of an additional carboxylate ligand in contributing to the protein’s picomolar affinity for LnIIIs, and it suggests a role of unusual Ni+1–H···Ni hydrogen bonds, in which LanM’s unique EF-hand proline residues are engaged, in selective LnIII recognition. This work sets the stage for a detailed mechanistic understanding of LanM’s Ln selectivity, which may inspire new strategies for binding, detecting, and sequestering these technologically important metals.Cosmidis, J., Nims, C.W., Diercks, D., Templeton, A.S., 2019. Formation and stabilization of elemental sulfur through organomineralization. Geochimica et Cosmochimica Acta 247, 59-82. sulfur (S(0)) is an important intermediate in the biogeochemical cycle of sulfur that is formed by chemical or biological oxidation of more reduced sulfur species. Given the restricted geochemical conditions under which S(0) should persist, the mechanisms whereby S(0) can be stabilized in the environment are not fully understood. Here we identify a process called “S(0) organomineralization”, by which S(0) minerals are produced and stabilized following the oxidation of hydrogen sulfide in the presence of numerous types of dissolved organics, including simple sugars and amino acids. The S(0) particles formed through this mechanism are closely associated with organics, which often form an envelope around the mineral. The organic envelopes are formed by self-assembly of the dissolved organic molecules in the presence of hydrogen sulfide and oxygen, and play in a role in the stabilization of S(0). Organic compound sulfurization probably plays an important role in the self-assembly mechanism, by causing the polymerization of relatively small dissolved organic molecules into solid, macromolecular, polymeric organics. The organomineralized S(0) particles present unique and complex morphologies, which are controlled by the type of dissolved organic compound present in the experimental media. Depending on the organics present, organomineralized S(0) can exist as different combinations of several crystal structures, including the non-thermodynamically stable β- and γ-S8 allotropes, which are most likely stabilized by their close association with the organic phase. We propose that complex particle morphology combined with the presence of metastable S(0) allotropes could be used as a signature of S(0) organomineralization in natural settings. S(0) organomineralization was obtained in the laboratory under a wide range of experimental conditions that span across geochemical conditions which can be encountered in many sulfidic environments. It is possible that the reaction between reduced sulfur species and organics may significantly affect the production and preservation of S(0) in numerous natural systems.Coward, E.K., Ohno, T., Sparks, D.L., 2019. Direct evidence for temporal molecular fractionation of dissolved organic matter at the iron oxyhydroxide interface. Environmental Science & Technology 53, 642-650. the importance of organic matter adsorption onto reactive iron-bearing mineral surfaces to carbon stabilization in soils and sediments has been well-established, fundamental understanding of how compounds assemble at the mineral interface remains elusive. Organic matter is thought to layer sequentially onto the mineral surface, forming molecular architecture stratified by bond strength and compound polarity. However, prominent complexation models lack experimental backing, despite the role of such architecture in fractionated, compound-dependent persistence of organic matter and modulating future perturbations in mineral stabilization capacity. Here, we use kinetic assays and ultrahigh resolution Fourier transform ion cyclotron resonance mass spectrometry under high temporal frequency to directly detect the molecular partitioning of organic matter onto an iron oxyhydroxide during adsorption. We observed three sequential intervals of discrete molecular composition throughout the adsorption reaction, in which rapid primary adsorption of aromatic compounds was followed by secondary lignin-like and tertiary aliphatic compounds. These findings, paired with observed differential fractionation along formulas nitrogen and oxygen content and decreasing selective sorption with reaction time, support “zonal” assembly models. This work presents direct detection of sequential molecular assembly of organic matter at the mineral interface, an important yet abstruse regulator of carbon stabilization and composition across temporal and spatial scales.Cubillos, C.F., Aguilar, P., Grágeda, M., Dorador, C., 2018. Microbial communities from the world's largest lithium reserve, Salar de Atacama, Chile: Life at high LiCl concentrations. Journal of Geophysical Research: Biogeosciences 123, 3668-3681. de Atacama is one of the largest global reservoirs of natural lithium brines (mean lithium concentration = 1,500 ppm), enabling Chile to be a leading producer of lithium products. This large salar (3,000 km2), located in the Atacama Desert at 2,300 m above sea level, is dominated by microorganisms; however, little is known about the microbes present in the brines associated with this economically important mining process. Here we study lithium as a modulator of microbial richness and diversity in brines representing natural conditions (34.7% salinity) and conditions prior to lithium production with a concentrated brine (55.6% salinity). Brines only supported a single archaeal family (Halobacteriaceae): natural brines included the archaeal genera Halovenus, Natronomonas, Haloarcula, and Halobacterium. Concentrated brines included the archaeal genera Halovenus, Halobacterium, and Halococcus. The most abundant bacterial families in natural brine were Rhodothermaceae and Staphylococcaceae; Xanthomonadaceae dominated the bacterial community in the concentrated brine. A comparison of entire microbial community (Archaea and Bacteria) revealed that only seven operational taxonomic units were shared between samples, all of which were Archaea. Further, our results showed that Bacteria were phylogenetically more diverse and rich in the concentrated brine, while archaeal diversity was maximized in the natural brine. The concentrated lithium brines of the Salar de Atacama represent one of the most saline environments described to date (dominated by LiCl). We suggest that elevated concentrations of lithium could greatly modulate microbial diversity and give insights into the adaptive biology of microorganisms required to cope with extremely high concentrations of salts that extend beyond that of NaCl, a far more commonly studied salt.Plain Language Summary: Lithium is a main component of many of the batteries that we rely on for our daily use. In the last years, nearly 40% of all lithium obtained globally was from a single fragile salt‐lake ecosystem: Salar de Atacama in the Atacama Desert of northern Chile. This salar has extremely saline waters called brines (dominated by NaCl, aka table salt), which are naturally highly concentrated in lithium and concentrated in evaporation ponds. In total, concentrated brines has a salinity of 55.6% (ocean salinity = 0.3%), representing one of the most saline environments described on Earth to date (dominated by lithium chloride). Our research has shown that concentrated brines support life and are dominated by hundreds of species of microorganisms. Due to saline stress these “extremophiles” have developed very special (and previously undescribed) strategies to survive in this lithium soup. These results have implications beyond Earth: they have marked implications for our understanding for the potential for life on Mars, where liquid water is known to occur as brine. Although lithium production has clear economic importance, our results show that we should consider how we will preserve these unusual ecosystems that act as reservoirs of unique microbial life.D’Atri, V., Fekete, S., Clarke, A., Veuthey, J.-L., Guillarme, D., 2019. Recent advances in chromatography for pharmaceutical analysis. Analytical Chemistry 90, 210-239. pharmaceutical industry is one of the most regulated industries worldwide, since the drug products have to be safe and effective. The levels of impurities and degradation products in active pharmaceutical ingredients (APIs) have to be strictly controlled and meet the specifications required by international authorities. Chromatography has been the technique of choice for many years to assess the chemical purity of drug substances and products and is widely used in the pharmaceutical industry, from research and development to quality control (QC) laboratories.Reversed-phase liquid chromatography (RPLC), which consists of a polar mobile phase and an apolar stationary phase, is the most appropriate technique to analyze mildly polar to apolar substances, that is, substances having an octanol–water partition coefficient (log P) between ?1 and 5.(1) Currently, RPLC is considered to be the gold standard in pharmaceutical analysis, and its success is attributed to the fact that this chromatographic mode matches perfectly with the physicochemical properties of drugs. Indeed, Lipinski developed his famous rule of thumb approximately 20 years ago to evaluate the drug-likeness of chemical compounds. Among the different criteria, he stated that an orally active drug should have a log P not greater than 5.(2) A few years later, this rule spawned some extensions, and it was demonstrated that log P should, ideally, be between ?0.4 and 5.6.(3) Considering this log P range, it is clear that drug lipophilicity fits well within the RPLC retention window.In addition to lipophilicity, another important characteristic of drugs is their ionic properties, and a significant proportion of drugs are ionizable (approximately 65% according to the world drug index),(4) including a large majority of basic substances (75% of the ionizable drugs). In RPLC, it is well-known that stationary phases should be deactivated (i.e., decrease silanol activity) to properly analyze basic drugs, as these drugs can interact with negatively charged residual silanols, leading to severe peak broadening and tailing. In the 1990s and later, many innovative strategies were developed by column providers to analyze basic drugs, including innovative end-capping procedures, ultrapure silica, development of hybrid silica materials, and high-pH stable stationary phases. Consequently, most of the innovations in column technology were implemented to answer the needs of the pharmaceutical industry.Due to the increasing costs and complexity of the drug development process in the early 2000s, there have been requests from the pharmaceutical industry to increase the overall performance of LC in terms of throughput and resolution. To achieve this goal, ultrahigh performance/pressure liquid chromatography (UHPLC) was developed in 2004 and consisted of using columns packed with sub-2 μm particles in combination with a chromatographic instrument capable of withstanding pressures up to 1000 (which has been recently extended up to 1500) bar.(5) Using this strategy, analysis times of 1–4 min (a valuable approach for fast method development)(6) and/or a peak capacity of 300–700 (required for complex impurity profiling) could be easily achieved.(7)Since 2011, there has been a growing interest in protein biopharmaceuticals (particularly monoclonal antibodies and related compounds) as new therapeutic agents in the pharmaceutical industry. Due to the specific analytical needs of these novel classes of biomolecules, several innovative chromatographic columns were introduced into the market. These columns possess (i) large pore sizes that limit restriction to diffusion and exclusion (300–1000 ?), (ii) enhanced kinetic performances to elute large solutes in sharp peaks (use of superficially porous particles),(8,9) and (iii) improved chemical inertness,(10) to limit protein adsorption and reduce silanol activity. In addition to the chromatographic stationary phases, bioinert LC systems (mostly plumbed with titanium) also appeared on the market.Today, all of the above-mentioned chromatographic innovations (i.e., deactivated stationary phases, UHPLC technology, columns/systems dedicated to biopharmaceutical analysis) have been integrated into most pharmaceutical laboratories involved in research and development. This allows for successful and rapid development of methods for the analysis of various APIs and products. However, this is still not the case in QC laboratories, since the employed methods have to be validated, which is why many of them are still running old-fashioned methods involving diethylamine, as a mobile phase additive to limit silanol activity, in combination with older-generation stationary phases 250 mm in length and packed with ≥5 μm particles.The goal of this contribution is to review the current and future trends in chromatography (mostly LC) applied to pharmaceutical analysis. Among the most important trends of the past few years, high-throughput analysis and automation, 2D-LC, supercritical fluid chromatography (SFC), hydrophilic interaction chromatography (HILIC), the combination of LC with low-cost MS detectors, automated method-development software, green LC, and the latest advances in GC are discussed in this article. In addition to these technological advances, several specific pharmaceutical applications are also illustrated, including the analysis of protein biopharmaceuticals, chiral drugs, genotoxic impurities, process analytical technology (PAT), and cleaning validation.da Silva, R.R., Vargas, F., Ernst, M., Nguyen, N.H., Bolleddu, S., del Rosario, K.K., Tsunoda, S.M., Dorrestein, P.C., Jarmusch, A.K., 2019. Computational removal of undesired mass spectral features possessing repeat units via a Kendrick mass filter. Journal of The American Society for Mass Spectrometry 30, 268-277. are a common component of chemical background which complicates data analysis and can impair interpretation. Undesired chemical background cannot always be addressed via pre-analytical methods, chromatography, or existing data processing methods. The Kendrick mass filter (KMF) is presented for the computational removal of undesired signals present in MS1 spectra. The KMF is analogous to mass defect filtering but utilizes homology information via Kendrick mass scaling in combination with chromatographic retention time and the number of observed signals. The KMF is intended to assist in situations in which current data processing methods to remove background, e.g., blank subtraction, are either not possible or effective. The major parameters affecting KMF were investigated using PEG 400 and NIST standard reference material 1950 (metabolites in human plasma). Further exploration of the KMF performance was tested using an extract of a swab known to contain polymers. An illustrative real-world example of skin analysis with polymeric signal is discussed. The KMF is also able to provide a high-level view of the compositionality of data regarding the presence of signals with repeat units and indicate the presence of different polymers.Dahkaee, K.P., Sadeghi, M.T., Fakhroueian, Z., Esmaeilzadeh, P., 2019. Effect of NiO/SiO2 nanofluids on the ultra interfacial tension reduction between heavy oil and aqueous solution and their use for wettability alteration of carbonate rocks. Journal of Petroleum Science and Engineering 176, 11-26. of the important factors in enhanced oil recovery (EOR), which leads to better oil flow in reservoirs and increases the recovery efficiency of the reservoirs, is the reduction of surface tension (S.T) and interfacial tension (IFT). The effect of NiO and SiO2 nanoparticles and their nanocomposites as NiO/SiO2 on the reduction of oil/water interfacial tension was investigated for the heavy oil of Soroush field located in Iran with a density of 0.965?g/cm3 and viscosity of 1310?cP?at 22?°C. NiO and SiO2 nanoparticles were produced by sol-gel-hydrothermal process and NiO/SiO2 nanocomposites were synthesized by co-precipitation-hydrothermal method. The interfacial tension of water/Soroush oil was measured to be 29.02?mN/m, as the reference, in the absence of nanoparticles. Water-based nanofluid of 30?wt% NiO/SiO2 and 28?wt% Fe@ NiO/SiO2 nanocomposites that benefits the synergism of the Fe promotor, decreased the IFT to 1.28?mN/m and less than 1?mN/m, respectively. In addition, the key factors such as concentration, aging time and salinity affect were studied in variation of S.T and IFT. It was found that 8 v/v% of the 30?wt% NiO/SiO2 diluted in water had the best efficiency in reducing the S.T and IFT, while preheating time of nanofluids and salinity of water that the nanofluid dissolved in had negligible impacts on surface and interfacial tension. Moreover, as the 30?wt% NiO/SiO2 nanocomposites were essentially hydrophobic, novel hydrophilic and eco-friendly nanocomposites of 30?wt% NiO/SiO2 were also synthesized through smart surface modifications by polyethylene glycol (PEG 6000) and polydimethylsiloxane. It was shown that the surface-modified nanocomposites could reduce the S.T and IFT significantly and alter the wettability of a strong oil-wet carbonate rock to water-wet condition.Dai, A., Luo, D., Song, M., Liu, J., 2019. Arctic amplification is caused by sea-ice loss under increasing CO2. Nature Communications 10, 121. in the Arctic has been much faster than the rest of the world in both observations and model simulations, a phenomenon known as the Arctic amplification (AA) whose cause is still under debate. By analyzing data and model simulations, here we show that large AA occurs only from October to April and only over areas with significant sea-ice loss. AA largely disappears when Arctic sea ice is fixed or melts away. Periods with larger AA are associated with larger sea-ice loss, and models with bigger sea-ice loss produce larger AA. Increased outgoing longwave radiation and heat fluxes from the newly opened waters cause AA, whereas all other processes can only indirectly contribute to AA by melting sea-ice. We conclude that sea-ice loss is necessary for the existence of large AA and that models need to simulate Arctic sea ice realistically in order to correctly simulate Arctic warming under increasing CO2.Dai, J., Zhang, J., Chen, C., 2019. Influence of resins on crystallization and gelation of waxy oils. Energy & Fuels 33, 185-196. the present work, we employed model oil systems to examine the effects of resins upon the gelation and crystallization of waxy oils. Two types of waxes were explored, namely, n-tetracosane (wax A) and a commercial wax with a melting temperature of 52–54 °C (wax B). The resins were extracted from a deoiled asphalt from Venezuelan residue by the saturates, aromatics, resins, and asphaltenes fractionation method. The results from negative-ion electrospray ionization Fourier transform ion cyclotron resonance-mass spectrometry suggest that resins consist of one to four fused benzenes rings or one to two fused naphthalene rings constructed by N1, N1O1, N1S1, N1O1S1, N1O2, O1, O1S1, and O2 class species containing stacking aromatic rings. For both types of waxes examined, adding resins to the waxy oils suppresses wax precipitation and modifies the morphology of wax crystals, which collectively leads to lower gelation temperature and lower yield stress. Up to 7 °C of reduction in gelation temperature, 60% of reduction in yield stress, and 6 °C of reduction in wax appearance temperature were achieved when the waxy oils contain 7 wt % resins. Whereas for the wax A model oil, the gelation temperature decreases gradually with increasing resin content, for the wax B model oil, the resin effect is pronounced only at the resin concentration below 0.2 wt %. The reduction in yield stress caused by adding resins is also greater for the wax A model oil than wax B model oil. The different resin effects for the wax A model oil and wax B model oil might be caused by the compositional variations between wax A and wax B.Dai, L., Wang, Y., Liu, Y., Ruan, R., Yu, Z., Jiang, L., 2019. Comparative study on characteristics of the bio-oil from microwave-assisted pyrolysis of lignocellulose and triacylglycerol. Science of The Total Environment 659, 95-100. pyrolysis of Camellia oleifera shell (COS) and stillingia oil (SO) was performed in the temperature range of 400–600?°C. The effects of feedstock and pyrolysis temperatures on product yield and bio-oil composition were discussed in detail. The bio-oil yield from COS pyrolysis varied from 37.30?wt% to 40.27?wt%, which was 11.32?wt% to 21.62?wt% lower than that from SO pyrolysis. Gas chromatography–mass spectrometry analysis indicated that SO bio-oil was rich in hydrocarbons, whereas COS pyrolysis produced mainly oxygen-containing compounds predominantly comprising phenols and acids. Fourier transform infrared and 1H-nuclear magnetic resonance spectra showed significant differences in the chemical structure of bio-oils from COS and SO pyrolysis. Elemental-composition and physical-property analyses further revealed that SO bio-oils were similar to gasoline and heavy fuel oil.Daly, R.A., Roux, S., Borton, M.A., Morgan, D.M., Johnston, M.D., Booker, A.E., Hoyt, D.W., Meulia, T., Wolfe, R.A., Hanson, A.J., Mouser, P.J., Moore, J.D., Wunch, K., Sullivan, M.B., Wrighton, K.C., Wilkins, M.J., 2019. Viruses control dominant bacteria colonizing the terrestrial deep biosphere after hydraulic fracturing. Nature Microbiology 4, 352-361. deep terrestrial biosphere harbours a substantial fraction of Earth’s biomass and remains understudied compared with other ecosystems. Deep biosphere life primarily consists of bacteria and archaea, yet knowledge of their co-occurring viruses is poor. Here, we temporally catalogued viral diversity from five deep terrestrial subsurface locations (hydraulically fractured wells), examined virus–host interaction dynamics and experimentally assessed metabolites from cell lysis to better understand viral roles in this ecosystem. We uncovered high viral diversity, rivalling that of peatland soil ecosystems, despite low host diversity. Many viral operational taxonomic units were predicted to infect Halanaerobium, the dominant microorganism in these ecosystems. Examination of clustered regularly interspaced short palindromic repeats–CRISPR-associated proteins (CRISPR–Cas) spacers elucidated lineage-specific virus–host dynamics suggesting active in situ viral predation of Halanaerobium. These dynamics indicate repeated viral encounters and changing viral host range across temporally and geographically distinct shale formations. Laboratory experiments showed that prophage-induced Halanaerobium lysis releases intracellular metabolites that can sustain key fermentative metabolisms, supporting the persistence of microorganisms in this ecosystem. Together, these findings suggest that diverse and active viral populations play critical roles in driving strain-level microbial community development and resource turnover within this deep terrestrial subsurface ecosystem.Dandamudi, K.P.R., Muppaneni, T., Markovski, J.S., Lammers, P., Deng, S., 2019. Hydrothermal liquefaction of green microalga Kirchneriella sp. under sub- and super-critical water conditions. Biomass and Bioenergy 120, 224-228. liquefaction (HTL) is one of the promising and reliable thermochemical conversion processes capable of converting wet biomass feedstock into renewable bio-oils. In this study, microalga Kirchneriella sp. was liquefied under hydrothermal conditions in a stainless-steel batch reactor. Various process parameters such as reaction temperature, pressure, biomass solid loading, and reaction duration were varied from 200 to 375?°C, 9–25?MPa, 10–20%, and 15–60?min, respectively. A one-factor-at-a-time approach was employed, and comprehensive experimental runs were further performed at 10% solid loading and a reaction time of 30?min. The maximum bio-crude yield (45.5%) was obtained at 300?°C, 9?MPa, with 10% solid loading and 30?min reaction duration. Fresh algal biomass, bio-oil and biochar samples were characterized by the ultimate and proximate analyses. The bio-oil and bio-char samples obtained at 300?°C, 9?MPa, with 10% solid loading and 30?min reaction duration have a higher heating value of 37.52 and 23.48?MJ?kg?1, respectively. The HTL aqueous phase was analyzed for potential co-products by spectrophotometric techniques and is rich in soluble carbohydrates, dissolved ammoniacal nitrogen and phosphates. The metal impurities in the algae, bio-oil, and biochar were identified by ICP-OES where algae and biochar contain a large proportion of phosphorous and magnesium.Dang, H., Li, J., 2018. Climate tipping-point potential and paradoxical production of methane in a changing ocean. Science China Earth Sciences 61, 1714-1727. global warming potential of methane (CH4) is about 30 times stronger than that of carbon dioxide (CO2) over a century timescale. Methane emission is hypothesized to have contributed to global climate change events and mass extinctions during Earth’s history. Therefore, the study of CH4 production processes is critically important to the understanding of global climate change. It has been a dogma that biogenic CH4 detectable in the oceans originates exclusively from the anaerobic metabolic activity of methanogenic archaea in hypoxic and anoxic environments, despite reports that many oxic surface and near-surface waters of the world’s oceans are CH4 -supersaturated, thereby rendering net sea-to-air emissions of CH4. The phenomenon of CH4 production in oxic marine waters is referred to as the “ocean methane paradox”. Although still not totally resolved, recent studies have generated several hypotheses regarding the sources of CH4 production in oxic seawater. This review will summarize our current understanding of the importance of CH4 in the global climate and analyze the biological processes and their underpinning mechanisms that lead to the production of CH4 in oxic seawater environments. We will also tentatively explore the relationships of these microbial metabolic processes with global changes in climate and environment.David, F., Ochiai, N., Sandra, P., 2019. Two decades of stir bar sorptive extraction: A retrospective and future outlook. TrAC Trends in Analytical Chemistry 112, 102-111. bar sorptive extraction (SBSE) has been developed nearly 20 years ago and was commercialized as Twister very soon after its introduction. Main appreciated features by its users are the solventless extraction, predictable extraction efficiencies, very high sensitivities when applied in combination with thermal desorption (TD) - GC-MS, multiple use for determinations in gaseous and aqueous matrices and excellent repeatability and reproducibility when polydimethylsiloxane (PDMS) is applied as sorptive phase. These features originate from the unique characteristics of PDMS, with low glass transition temperature, very low bleeding profile at high temperatures after appropriate conditioning, and excellent diffusivity and permeability. PDMS-SBSE is intensively applied in different areas (environmental, food, biofluids, drugs, etc.) for sensitive determinations of solutes with a log P larger than 3. Of utmost importance for routine application of SBSE are its figures of merit and several studies have illustrated that SBSE on PDMS can be validated and standard operating procedures developed. For more polar solutes, different derivatization methods have been applied to enhance the hydrophobicity of the solutes and thus increasing the log P value. Over the years, other coating materials have been evaluated and/or developed for enhanced extraction of more polar compounds. Only a limited number, however, are operating in the sorptive or partitioning mode while only few of them have favorable thermal characteristics to be used in TD-GC-MS applications. To the best of our knowledge, only one has been commercialized namely a PDMS/ethylene glycol (EG) copolymer placed on an inert metal grid for mechanical stabilization. Other home-made coatings, such as monoliths, polyurethane foams or other polymers are mostly used in combination with liquid desorption, are not commercially available in ready-to-use stir bar format and, therefore, not accessible for independent in-depth testing. Alternatively, two other methods applying PDMS stir bars were recently developed to extend SBSE to more polar solutes: solvent assisted SBSE (SA-SBSE) and ice concentration linked with extractive stirrer (ICECLES) that is based on freeze concentration. This review on SBSE is highlighting both developments and future perspectives of SBSE are outlined.De Mets, F., Van Melderen, L., Gottesman, S., 2019. Regulation of acetate metabolism and coordination with the TCA cycle via a processed small RNA. Proceedings of the National Academy of Sciences 116, 1043-1052.: In bacteria, small RNAs pair with target mRNAs to rapidly adjust gene expression in response to environmental and physiological changes. In this study, we identified a small RNA, SdhX, in Escherichia coli, whose expression is dependent on expression of tricarboxylic acid cycle genes. SdhX adjusts carbon flux by negatively regulating acetate kinase levels, improving growth on acetate. SdhX also leads to increased resistance to hydroxyurea, as do deletions of acetate kinase. Balancing metabolic flux is important for all bacterial cells, and SdhX plays a major role in this process by linking expression of tricarboxylic acid cycle genes to regulation of acetate metabolism, thus playing a role in gating overflow metabolism.Abstract: Bacterial regulatory small RNAs act as crucial regulators in central carbon metabolism by modulating translation initiation and degradation of target mRNAs in metabolic pathways. Here, we demonstrate that a noncoding small RNA, SdhX, is produced by RNase E-dependent processing from the 3′UTR of the sdhCDAB-sucABCD operon, encoding enzymes of the tricarboxylic acid (TCA) cycle. In Escherichia coli, SdhX negatively regulates ackA, which encodes an enzyme critical for degradation of the signaling molecule acetyl phosphate, while the downstream pta gene, encoding the enzyme critical for acetyl phosphate synthesis, is not significantly affected. This discoordinate regulation of pta and ackA increases the accumulation of acetyl phosphate when SdhX is expressed. Mutations in sdhX that abolish regulation of ackA lead to more acetate in the medium (more overflow metabolism), as well as a strong growth defect in the presence of acetate as sole carbon source, when the AckA-Pta pathway runs in reverse. SdhX overproduction confers resistance to hydroxyurea, via regulation of ackA. SdhX abundance is tightly coupled to the transcription signals of TCA cycle genes but escapes all known posttranscriptional regulation. Therefore, SdhX expression directly correlates with transcriptional input to the TCA cycle, providing an effective mechanism for the cell to link the TCA cycle with acetate metabolism pathways.de Santana, F.B., de Souza, A.M., Poppi, R.J., 2019. Green methodology for soil organic matter analysis using a national near infrared spectral library in tandem with learning machine. Science of The Total Environment 658, 895-900. agriculture requires faster and automatic responses for fertility parameters, especially regarding soil organic matter (SOM). In Brazil, the standard methodology for SOM determination is a wet procedure based on the oxidation of the sample by an excess of potassium dichromate based on Walkley–Black method. This methodology has serious drawbacks, since, at a national level, generates approximately 600,000?L/year of toxic acid waste containing Cr3+ and possibly Cr6+, besides time consuming and expensive. Herein, we present a faster green methodology that can eliminate the generation of these hazardous wastes and reduces the costs of analysis by approximately 80%, democratizing the soil fertility information and increasing the productivity. The methodology is based on the use of a national near infrared spectral library with approximately 43,000 samples and learning machine data analysis based on a random forest algorithm. The methodology was validated by submitting the prediction results of 12 blind soil samples to a proficiency assay used for fertility soil laboratories qualification, receiving the maximum quality excellence index, indicating that it is suitable for use in routine analysis.Del Genio, A.D., Way, M.J., Amundsen, D.S., Aleinov, I., Kelley, M., Kiang, N.Y., Clune, T.L., 2018. Habitable climate scenarios for Proxima Centauri b with a dynamic ocean. Astrobiology 19, 99-125. nearby exoplanet Proxima Centauri b will be a prime future target for characterization, despite questions about its retention of water. Climate models with static oceans suggest that Proxima b could harbor a small dayside surface ocean despite its weak instellation. We present the first climate simulations of Proxima b with a dynamic ocean. We find that an ocean-covered Proxima b could have a much broader area of surface liquid water but at much colder temperatures than previously suggested, due to ocean heat transport and/or depression of the freezing point by salinity. Elevated greenhouse gas concentrations do not necessarily produce more open ocean because of dynamical regime transitions between a state with an equatorial Rossby–Kelvin wave pattern and a state with a day–night circulation. For an evolutionary path leading to a highly saline ocean, Proxima b could be an inhabited, mostly open ocean planet with halophilic life. A freshwater ocean produces a smaller liquid region than does an Earth salinity ocean. An ocean planet in 3:2 spin–orbit resonance has a permanent tropical waterbelt for moderate eccentricity. A larger versus smaller area of surface liquid water for similar equilibrium temperature may be distinguishable by using the amplitude of the thermal phase curve. Simulations of Proxima Centauri b may be a model for the habitability of weakly irradiated planets orbiting slightly cooler or warmer stars, for example, in the TRAPPIST-1, LHS 1140, GJ 273, and GJ 3293 systems.Dennell, R., 2019. Dating of hominin discoveries at Denisova. Nature 565, 571-572. Cave lies in a valley in the Altai Mountains of southern Siberia. Excavations began there 40 years ago, focusing on layers of material from the Middle Palaeolithic period (about 340,000 to 45,000 years ago) and the Initial Upper Palaeolithic (which is defined by the identification of types of stone tool, and often by the presence of items such as ornaments, and which corresponds to 45,000 to 40,000 years ago at this site). The excavations have provided many key insights into the lives of hominins belonging to branches of the evolutionary tree close to that of our own species, Homo sapiens. Douka et al.1 and Jacobs et al.2 now report their use of the latest dating techniques, which lead to a revised timeline of hominin-associated material in this cave.Previous excavations had uncovered types of ancient ornamental artefact that are often associated with early H. sapiens, such as bones shaped into pendants (Fig. 1) and decorative items made of mammoth ivory. However, the cave hit the news headlines in 2010 when analysis of ancient DNA3 from a bone in a Middle Palaeolithic layer indicated that the specimen was a previously unknown type of hominin from a branch of the evolutionary tree near H. sapiens. Such hominins were named Denisovans, and, on the basis of DNA analysis4, they are probably a sister taxon of Neanderthals.Neanderthals and Denisovans there during the Middle Palaeolithic. However, no signs of H. sapiens being present during that time have been found. Neanderthals and Denisovans existed there at too early a time for radiocarbon dating of the specimens, which is usually effective only for dates up to about 50,000 years ago. Other dating techniques, such as thermoluminesence and optical stimulated luminescence, have been the main approaches used to date such remains, although each of these methods has its own drawbacks.Knowing accurate timings of occupation at the cave would help to shed light on the presence and activities of early hominins, and might address whether the different species overlapped there. However, analysing ancient deposits is tricky. Layers can be disturbed by animal burrowing, subsidence or freeze–thawing cycles. Small items, such as fossil bones or stone tools, might be displaced from their original positions and not be the same age as that of the layer of deposits in which they were found (Fig. 2). Douka et al. report their dating of Neanderthal and Denisovan fossils of hominin specimens, as well as artefacts fashioned from bones. Jacobs and colleagues report dating information for the cave sediment deposits, obtained using optically stimulated luminescence, and presenting the most comprehensive dating work yet attempted for the deposits at Denisova Cave.Jacobs and colleagues present 103 dates for sediment deposits that range from more than 300,000 years ago to 20,000 years ago, and that extend across glacial and interglacial episodes spanning timescale stages termed marine isotope stage 9 (MIS 9) to MIS 2. Deposition of sediments at the site was episodic, with numerous gaps indicating periods when either there was no sedimentation or sediments were removed. There is some evidence of post-depositional disturbance, but the crucial late Middle Palaeolithic and Initial Upper Palaeolithic layers show relatively little sign of disturbance. This is the time frame that might mark the appearance at Denisova of our own species. However, when H. sapiens first appeared at the site is unknown.The authors analysed the remains of 27 species of large vertebrate, 100 species of small vertebrate (such as mammals and fishes) and 72 species of plant to make a reconstruction of the environment at Denisova. This reveals that the cave surroundings varied from being a broad-leafed forest in the warmest episodes to a tundra–steppe habitat during the coldest times. The authors’ results broadly agree with those from detailed climate reconstructions for the same time frame made at Lake Baikal7,8, located 1,600 kilometres to the east. The one exception is for the climate approximately 150,000 years ago, when pollen from Denisova indicates vegetation characteristic of warm, humid conditions, whereas the Lake Baikal data indicate cold conditions at that time. As Jacobs and colleagues point out, this discrepancy might be because the dates obtained using optical dating techniques have wide margins of uncertainty, and climatic conditions might have been unstable.Douka and colleagues focused on dating the hominin specimens and material from the Initial Upper Palaeolithic. Their results highlight the current capabilities of ancient-DNA analysis. Ancient DNA can be extracted from cave sediments4, and DNA from both Neanderthals and Denisovans has been detected previously4 at the site. But it is now possible to identify the taxon to which an otherwise unidentifiable bone fragment belongs by analysing a protein called collagen and using a technique known as zooarchaeology by mass spectrometry (ZooMS). The ability to use ZooMS to analyse thousands of bone fragments from cave excavations across Eurasia could enable the distribution of Neanderthals, Denisovans and our species to be mapped at a level of detail that would have seemed like science fiction just a few years ago. A total of 4,527 bone fragments from Denisova have been analysed in this way, with 2,212 of these being reported by Douka and colleagues.Because of the specimens’ ages, only a fossil named Denisova 14, which Douka and colleagues dated to around 46,300±2,600 years ago, could be analysed by carbon dating. And the authors could not determine the species to which Denisova 14 belonged because insufficient DNA was available. Most of the hominin samples were dated using a method that uses DNA sequences from cellular organelles called mitochrondria, to make comparisons between a sample and reference sequences from other hominins. The authors then generated a relative sequence of the ages of the Denisova fossils. This revealed that a specimen named Denisova 2 (species identified as being Denisovan) is the oldest fossil identified at the site (estimated to be 122,700–194,400 years old). Two Neanderthal fossils, Denisova 5 (90,900–130,000 years old) and Denisova 15 (91,400–130,300 years old), were dated to a similar time interval and are both older than Denisova 11 (79,300–118,100 years old), which is a fossil from an individual that had both Denisovan and Neanderthal individuals as parents9. There are uncertainties over these attempts at dating using genetic analysis, as the authors point out. Nevertheless, this is the first time that we have had this type of information about the pattern of occupation of Denisova Cave by Neanderthals and Denisovans. Douka and colleagues dated the Denisovan specimens using an approach called Bayesian modelling. Their favoured version of this approach incorporated radiocarbon and optically stimulated luminescence ages, information about the excavated layers, and timing based on genetic data. Their modelled ages of some hominin specimens did not always match the age of the sediments in which the fossils were found. Although the DNA-based estimated ages for Denisova 5 and Denisova 8 are consistent with the optical ages for their associated layers, Denisova 3 and Denisova 4 are older than expected compared with the layers in which they were found, and Denisova 2 and Denisova 11 are younger than expected compared with the layers in which they were found. These discrepancies might indicate uncertainties in the genetically obtained age estimates, or that some fossils were redeposited from their initial site of deposit. Although there might still be some uncertainty about the detailed ages of the remains — given the nature and complexity of the deposits and the dating methods used — the general picture is now clear. Deposition of sediment deposits at Denisova was episodic, but extends from MIS 9 to MIS 2, and the site was occupied by Denisovans and by Neanderthals in both cold and warm periods from approximately 200,000 to 50,000 years ago. The challenge will now be to identify the hominin(s) associated with the Initial Upper Palaeolithic. The timing of the onset of the Initial Upper Palaeolithic period assemblages at Denisova was estimated by radiocarbon dating by Douka and colleagues — with two bone artefacts dated to 42,660–48,1000 and 41,590–45,700 years old. On the basis of human DNA identified at a site called Ust’-Ishim, it is estimated that H. sapiens reached Siberia at least 46,880 to 43,200 years ago10. This raises the possibility that our species contributed to the deposits in the Initial Upper Palaeolithic at Denisova. Some researchers argue on archaeological grounds11 that the Initial Upper Palaeolithic in the Altai Mountain region was an indigenous development that followed on from that of the preceding local Middle Palaeolithic, whereas others argue that it represents an intrusive development of those arriving from outside the region. One possibility is that the Initial Upper Palaeolithic development at Denisova was made by hybrids of Denisovans and H. sapiens, given the evidence for interbreeding between Neanderthals, Denisovans and H. sapiens in MIS 3. A way of testing these hypotheses would be to find and analyse ancient hominin DNA in the Initial Upper Palaeolithic layers. There is still much to learn from Denisova. The work by Douka, Jacobs and their respective colleagues creates an important foundation for such efforts by providing a rigorous and compelling timeline for the cave sediments and its contents. References1. Douka, K. et al. Nature 565, 640–644 (2019).2. Jacobs, Z. et al. Nature 565, 594–599 (2019).3. Krause, J. et al. Nature 464, 894–897 (2010).4. Slon, V. et al. Science 356, 605–608 (2017).5. Reich, D. et al. Nature 468, 1053–1060 (2010).6. Prüfer, K. et al. Nature 505, 43–49 (2014).7. Prokopenko, A. A., Hinnov, L. A., Williams, D. F. & Kuzmin, M. I. Quat. Sci. Rev. 25, 3431–3457 (2006).8. Grygar, T. et al. Palaeogeogr. Palaeoclimatol. Palaeoecol. 250, 50–67 (2007).9. Slon, V. et al. Nature 561, 113–116 (2018).10. Fu, Q. et al. Nature 514, 445–449 (2014).11. Derevianko, A. P. Archaeol. Ethnol. Anthropol. Eurasia 501–508 (2005).Devièse, T., Massilani, D., Yi, S., Comeskey, D., Nagel, S., Nickel, B., Ribechini, E., Lee, J., Tseveendorj, D., Gunchinsuren, B., Meyer, M., P??bo, S., Higham, T., 2019. Compound-specific radiocarbon dating and mitochondrial DNA analysis of the Pleistocene hominin from Salkhit Mongolia. Nature Communications 10, Article 274. skullcap found in the Salkhit Valley in?northeast Mongolia is, to our knowledge, the only Pleistocene hominin fossil found in the country. It was initially described as an individual with possible archaic affinities, but its ancestry has been debated since the discovery. Here, we determine the age of the Salkhit skull by compound-specific radiocarbon dating of hydroxyproline to 34,950–33,900 Cal. BP (at 95% probability), placing the Salkhit individual in the Early Upper Paleolithic period. We reconstruct the complete mitochondrial genome (mtDNA) of the specimen. It falls within a group of modern human mtDNAs (haplogroup N) that is widespread in Eurasia today. The results now place the specimen into its proper chronometric and biological context and allow us to begin integrating it with other evidence for the human occupation of this region during the Paleolithic, as well as wider Pleistocene sequences across Eurasia.Dhaulaniya, A.S., Balan, B., kumar, M., Agrawal, P.K., Singh, D.K., 2019. Cold survival strategies for bacteria, recent advancement and potential industrial applications. Archives of Microbiology 201, 1-16. have evolved themselves to thrive under various extreme environmental conditions such as extremely high or low temperature, alkalinity, and salinity. These microorganisms adapted several metabolic processes to survive and reproduce efficiently under such extreme environments. As the major proportion of earth is covered with the cold environment and is exploited by human beings, these sites are not pristine anymore. Human interventions are a great reason for disturbing the natural biogeochemical cycles in these regions. The survival strategies of these organisms have shown great potential for helping us to restore these pristine sites and the use of isolated cold-adapted enzymes from these organisms has also revolutionized various industrial products. This review gives you the insight of psychrophilic enzyme adaptations and their industrial applications.Ding, X., Qiu, Z., Qu, K., Li, Z., 2019. Molecular dynamics simulations of noble gas fractionation during diffusion through silica nanopores. ACS Earth and Space Chemistry 3, 62-69. retention and slight enrichment of Kr–Xe relative to atmospheric levels have been found in biogenic chert samples. Previous studies suggested that the incorporation of noble gas atoms is dependent upon the structure rather than the environment. In this study, we perform molecular dynamics simulations of dissolved noble gas atomic diffusion through 1–4 nm diameter silica pores. Bulk-liquid-like water does not exist in the 1 nm diameter nanopores, which hinder noble gas diffusion into or out of the pores. In ≥2 nm diameter nanopores, noble gas atoms transport with bulk-liquid-like water into the center of the pores but size-controlled diffusive separation occurs at the layer of surface water and in the interior of the silica structure. The motion of large atoms (Kr and Xe) in surface water is governed by significant adsorption. Relatively small Ne atoms are able to cross the surface water layer and diffuse into the crystal interior. As a result of its moderate size and the negligible interaction with the interfacial surface, Ar lies beyond the adsorption and silica structure diffusion regimes. Therefore, our simulation results indicate that noble gas entrapment is expected to occur in nanoscale fluid circulation during sediment-to-chert lithification.Domeier, M., Torsvik, T.H., 2019. Full-plate modelling in pre-Jurassic time. Geological Magazine 156, 261-280. half-century has passed since the dawning of the plate tectonic revolution, and yet, with rare exception, palaeogeographic models of pre-Jurassic time are still constructed in a way more akin to Wegener's paradigm of continental drift. Historically, this was due to a series of problems – the near-complete absence of in situ oceanic lithosphere older than 200?Ma, a fragmentary history of the latitudinal drift of continents, unconstrained longitudes, unsettled geodynamic concepts and a lack of efficient plate modelling tools – which together precluded the construction of plate tectonic models. But over the course of the last five decades strategies have been developed to overcome these problems, and the first plate model for pre-Jurassic time was presented in 2002. Following on that pioneering work, but with a number of significant improvements (most notably longitude control), we here provide a recipe for the construction of full-plate models (including oceanic lithosphere) for pre-Jurassic time. In brief, our workflow begins with the erection of a traditional (or ‘Wegenerian’) continental rotation model, but then employs basic plate tectonic principles and continental geology to enable reconstruction of former plate boundaries, and thus the resurrection of lost oceanic lithosphere. Full-plate models can yield a range of testable predictions that can be used to critically evaluate them, but also novel information regarding long-term processes that we have few (or no) alternative means of investigating, thus providing exceptionally fertile ground for new exploration and discovery.Doner, Z., Kumral, M., Demirel, I.H., Hu, Q., 2019. Geochemical characteristics of the Silurian shales from the central Taurides, southern Turkey: Organic matter accumulation, preservation and depositional environment modeling. Marine and Petroleum Geology 102, 155-175. Silurian-age organic-rich and organic-lean shales, located within Ayd?nc?k, Gülnar and Silifke districts of Mersin province in central Taurides, southern Turkey, is considered as an unconventional resources. These organic-rich and -lean shales are controlled by the similar geological, tectonic and sedimentary processes, as the passive margin basin has acted as the provenance region throughout the deposition of these shales. Geochemical data of major and trace elements obtained for a total of 39 outcrop samples were interpreted to determine the depositional model, water column productivity, amount of organic matter and preservation conditions. Total organic carbon (TOC) values of these organic-rich and -lean shales range from 0.56 to 4.06?wt. % and 0.01 to 0.38?wt. %. Several redox indicators, such as V systematics (V/Sc, V/Ni) as well as ratios of Ni/Co, Th/U and Mo/Mn, showed that the organic-rich shales were deposited in suboxic to anoxic environments, as opposed to oxic-dysoxic conditions for organic-lean ones. However, organic matter enrichment is not restrained by water column productivity, as indicated by a lack of correlation between TOC and productivity indexes (P/Ti and Ba/Al), but rather probably controlled by dysoxic-anoxic water column environment. In addition, a detrital material input cannot be ignored for its influence on organic matter enrichment in the shale deposition. The increase in the clastic fluxes probably resulted from the deposition in the extended shelf with coastal upwelling. A lack of correlation between K2O, Al2O3, SiO2 and TOC contents among these shales imply that clay minerals may not influence organic matter preservation. According to w(La)N/w(Yb)N and ΣREE values, a high sedimentation rate is determined during the shale deposition, which would result in a dilution of organic matter. Furthermore, slight marine influences with sulphur limitation and low salinity, semi-arid/warm to humid-warm climatic conditions are widespread, according to total sulphur (TS), Sr/Ba, Sr/Cu, chemical index of alteration (CIA), C-value and related discrimination diagrams. In the end, a depositional model of the central Taurides shales is established to display an excellent preservation condition as the major controlling factor for organic matter enrichment in the Silurian shales.Dong, B., Long, X., Li, J., Yang, X., Zhao, B., Luo, J., 2019. Mo isotopic variations of a Cambrian sedimentary profile in the Huangling area, South China: Evidence for redox environment corresponding to the Cambrian Explosion. Gondwana Research 69, 45-55. radiation of macroscopic animals in the Early Cambrian, commonly be called as ‘Cambrian explosion’, had a close relationship with Earth oxygenation. These macrofossils are widely preserved within the Early Cambrian in the northern and western Yangtze Craton. In order to show the casual relationship between animal evolution and Earth redox environment, Mo content and isotopic composition analyses have been conducted on dolomites of the Tianzhushan Formation and the black shales of the Shuijingtuo Formation from the lowermost Cambrian profile in the eastern Huangling dome, northern Yangtze Craton. The calcitic dolostones from the Tianzhushan Formation display lower concentrations of Mo contents (0.055–0.666?ppm) than that of the black silty shales from the Shuijingtuo Formation (6.0–172?ppm). This magnitude difference is most likely related to the different lithologies due to Mo enrichment in shales. The Mo isotope values (δ98/95Mo) of the calcitic dolostones for the Tianzhushan Formation vary from ?0.73‰ to 0.41‰. In comparison, the black sandy shales from the Shuijingtuo Formation exhibit δ98/95Mo of ?1.04–1.84‰, including 5 samples from the earliest Shuijingtuo Formation displaying systematically higherδ98/95Mo values (0.09–1.84‰) than those of the other 5 samples from upper layers (δ98/95Mo?=??1.04 to ?0.19‰). These geochemical data suggest that the redox environment of the early Cambrian is fluctuating, and the peak oxygenation of the ocean had already reached a level similar to modern environments. According to the Mo concentrations and δ98/95Mo data, the sedimentary succession can be divided into five intervals, which are closely correlated to the episodic evolution of early life in the Cambrian. Together with the available published data from other profiles in the Yangtze Craton, our new data reveal that the higher oxidation environment had a positive effect on the evolution of early life.Dores-Sousa, J.L., De Vos, J., Eeltink, S., 2019. Resolving power in liquid chromatography: A trade-off between efficiency and analysis time. Journal of Separation Science 42, 38-50. review describes chromatographic dispersion and different plate-height models frequently used to assess the chromatographic performance of ultra-high-pressure liquid chromatography column technology. Furthermore, different performance indices, including the resolution, the separation impedance, and kinetic plots are discussed allowing to quantify and visualize the resolving power in liquid chromatography. The construction of kinetic plots is explained, and different visualization approaches are highlighted. Finally, key instrument and column-technology developments to advance the kinetic performance limits are discussed and selected state-of-the-art applications are highlighted.Dores-Sousa, J.L., Fernández-Pumarega, A., De Vos, J., L?mmerhofer, M., Desmet, G., Eeltink, S., 2019. Guidelines for tuning the macropore structure of monolithic columns for high-performance liquid chromatography. Journal of Separation Science 42, 522-533. The ability to control the external porosity and to tune the dimensions of the macropore size on multiple length scales provides the possibility of tailoring the monolithic support structure towards separation performance. This paper discusses the properties of conventional polymer?monolithic stationary phases and its limitations regarding the effects of morphology on kinetic performance. Furthermore, guidelines to improve the macropore structure are discussed. The optimal monolithic macropore structure is characterized by high external porosity (while maintaining ultra-high-pressure stability), high structure homogeneity, polymer globule clusters in the submicron range, and macropores with a diameter tuned toward speed (small diameter in the 100?500 nm range using short beds) or efficiency (larger macropores in the range of 500?nm?1 ?m allowing the use of longer column formats). Finally, promising approaches to control the morphology are discussed.Dougherty, A.J., Bartholet, Z.T., Chumsky, R.J., Delano, K.C., Huang, X., Morris, D.K., 2018. The liquidus temperature for methanol-water mixtures at high pressure and low temperature, with application to Titan. Journal of Geophysical Research: Planets 123, 3080-3087. Methanol is a potentially important impurity in subsurface oceans on Titan and Enceladus. We report measurements of the freezing of methanol-water samples at pressures up to 350?MPa using a volumetric cell with sapphire windows. For low concentrations of methanol, the liquidus temperature is typically a few degrees below the corresponding ice freezing point, while at high concentrations it follows the pure methanol trend. In the Ice-III regime, we observe several long-lived metastable states. The results suggest that methanol is a more effective antifreeze than previously estimated and might have played an important role in the development of Titan's subsurface ocean.Douka, K., Slon, V., Jacobs, Z., Ramsey, C.B., Shunkov, M.V., Derevianko, A.P., Mafessoni, F., Kozlikin, M.B., Li, B., Grün, R., Comeskey, D., Devièse, T., Brown, S., Viola, B., Kinsley, L., Buckley, M., Meyer, M., Roberts, R.G., P??bo, S., Kelso, J., Higham, T., 2019. Age estimates for hominin fossils and the onset of the Upper Palaeolithic at Denisova Cave. Nature 565, 640-644. Cave in the Siberian Altai (Russia) is a key site for understanding the complex relationships between hominin groups that inhabited Eurasia in the Middle and Late Pleistocene epoch. DNA sequenced from human remains found at this site has revealed the presence of a hitherto unknown hominin group, the Denisovans1,2, and high-coverage genomes from both Neanderthal and Denisovan fossils provide evidence for admixture between these two populations3. Determining the age of these fossils is important if we are to understand the nature of hominin interaction, and aspects of their cultural and subsistence adaptations. Here we present 50 radiocarbon determinations from the late Middle and Upper Palaeolithic layers of the site. We also report three direct dates for hominin fragments and obtain a mitochondrial DNA sequence for one of them. We apply a Bayesian age modelling approach that combines chronometric (radiocarbon, uranium series and optical ages), stratigraphic and genetic data to calculate probabilistically the age of the human fossils at the site. Our modelled estimate for the age of the?oldest Denisovan fossil suggests that this group was present at the site as early as 195,000?years ago (at 95.4% probability). All Neanderthal fossils—as well as Denisova?11, the daughter of a Neanderthal and a Denisovan4—date to between 80,000 and 140,000?years ago. The youngest Denisovan dates to 52,000–76,000?years ago. Direct radiocarbon dating of Upper Palaeolithic tooth pendants and bone points yielded the earliest evidence for the production of these artefacts in northern Eurasia, between?43,000?and?49,000?calibrated years before present (taken as ad?1950). On the basis of current archaeological evidence, it may be assumed that these artefacts are associated with the Denisovan population. It is not currently possible to determine whether anatomically modern humans were involved in their production, as modern-human fossil and genetic evidence of such antiquity has not yet been identified in the Altai region.Driscoll, P., 2019. Geodynamo recharged. Nature Geoscience 12, 83-84. from a weak and erratic geomagnetic field to a more stable one around 560 million years ago, inferred from palaeomagnetic measurements, suggests that the inner core may have solidified around that time, much later than thought.Ever since Earth’s solid inner core was discovered1 in 1936, the age of its nucleation — when iron first crystallized at the centre of the planet — has been the subject of intense speculation. Estimates span nearly the age of Earth itself. Pinning down the time and temperature at which iron first began to freeze would be an extremely valuable data point. It would help unravel Earth’s thermal history, which governs global dynamic processes such as volcanism, tectonics and magnetic field generation. Writing in Nature Geoscience, Bono and colleagues2 present palaeomagnetic evidence that Earth’s magnetic field displayed unusual behaviour during the Ediacaran period (635–541 Myr ago (Ma)), evidence that is intriguingly consistent with predictions of numerical dynamo models for the signature of inner core nucleation.Inner core nucleation affects the geomagnetic field by inducing compositional convection. Earth’s solid inner core forms as the liquid iron outer core cools and freezes. During this solidification, light elements such as silicon or oxygen are rejected from the solid. This process makes the surrounding liquid lighter on average than the background iron-rich fluid. This light-element-rich fluid then rises through the outer core, driving compositional convection as the inner core grows. Therefore, inner core nucleation should mark a distinct change in the way the geodynamo operated.Investigations of the magnetic signature of inner core nucleation, with the help of numerical dynamo models, predict that weak thermal convection prior to inner core nucleation produced a regime of low magnetic intensity and non-dipolar field geometry followed by a stronger axial dipole after nucleation3,4. Therefore, the predicted magnetic signature of inner core nucleation is a dramatic shift from a weak and scattered geomagnetic field to a stable dipolar field around 600 Ma (Fig.). However, such predictions have proved difficult to test because of the paucity of palaeomagnetic records during the time period in question.Bono and colleagues2 have uncovered new magnetic evidence that supports the predictions of a young inner core. Using palaeomagnetic measurements from samples of the 565-Myr-old Sept-?les intrusive suite in Quebec, Canada, they identify a prolonged period with magnetic field intensity about ten times lower than the modern day field. Their data imply that the geodynamo remained anomalous for at least 75 kyr. They also find anomalously large directional scatter, implying the magnetic field at the time was not in a quiescent axial dipolar state, where the magnetic and rotational poles are coincident. Weak intensities and directional swings are known to occur during polarity reversals, but such events typically only last about 5 kyr, far shorter than Bono et al.’s data imply.These measurements join mounting evidence supporting an anomalous palaeomagnetic field during the Ediacaran period that has previously been interpreted as resulting from rapid tectonic motion5, hyper-frequent polarity reversals6,7 and even an equatorial dipole8. However, Bono et al. argue that all of these measurements are better interpreted as signatures of a weak dynamo that was about to collapse. If so, the nucleation of the inner core may have occurred right in the nick of time to recharge the geodynamo and save Earth’s magnetic shield.A late start for the solidification around 500–700 Ma implies that the inner core is two to three times younger than previously thought. A young inner core is consistent with thermal history models of the Earth9,10,11,12 that predict a large transfer of heat from the core to the mantle due, indirectly, to upward revisions to the thermal conductivity of the core. Although the core thermal conductivity itself does not affect the freezing temperature, it has important implications for convection: high thermal conductivity means efficient heat conduction through the core. In turn, it implies that there is less heat available to drive convection and induce a magnetic field. These considerations lead to the so-called ‘new core paradox’13, where dynamo action could have ceased prior to nucleation of the inner core without an alternative energy source. Two possible resolutions present themselves. Either a buried heat source, such as radiogenic heating, produced enough heat to keep the heat flow high and the core hot over billions of years9,12, or material has been precipitating out of the core driving compositional convection to counteract the decline in thermal convection14,15.The first solution is often disfavoured because radiogenic elements prefer to stay in the mantle than the core. This does not exclude the possibility of a hidden mantle reservoir, but preventing it from mixing with the mantle introduces another challenge. The second solution depends on the poorly constrained chemistry of core precipitation and it does not slow the cooling of the mantle — which would be needed to explain why the mantle has not been molten in the recent past. Addressing these mysteries remains paramount to understanding how Earth has maintained a magnetic field over much, and possibly all, of its history.Although connecting palaeomagnetic observations to the thermal history of the interior challenges several long-held assumptions, it also suggests a way forward. Additional palaeomagnetic observations, both directions and intensities, are the obvious next step to provide a clearer picture of the state of the core around this time. Experiments on the solidification and conductivity of iron will further constrain the thermodynamics of the core. Lastly, numerical models of the evolving core can produce detailed predictions that test how all of these components come together.Bono and colleagues2 present intriguing palaeomagnetic measurements that imply that a weak geodynamo in the Ediacaran was indicative of a fully liquid core at that time. Owing to its inaccessibility, the collective efforts of palaeomagnetists, experimentalists and theorists are essential to advance our knowledge of how the geodynamo has endured and when the inner core formed.References1. Lehmann, I. Publ. Bur. Centr. Seism. Internat. Serie A 14, 87–115 (1936).2. Bono, R. K., Tarduno, J. A., Nimmo, F. & Cottrell, R. D. Nat. Geosci. (2019).3. Driscoll, P. E. Geophys. Res. Lett. 43, 5680–5687 (2016).4. Landeau, M., Aubert, J. & Olson, P. Earth Planet. Sci. Lett. 465, 193–204 (2017).5. Robert, B., Greff-Lefftz, M. & Besse, J. Geochem. Geophys. Geosyst. 19, 3478–3495 (2018).6. Bazhenov, M. L. et al. Earth Planet. Sci. Lett. 435, 124–135 (2016).7. Halls, H. C., Lovette, A., Hamilton, M. & S?derlund, U. Precambrian Res. 257, 137–166 (2015).8. Abrajevitch, A. & Van der Voo, R. Earth Planet. Sci. Lett. 293, 164–170 (2010).9. Driscoll, P. & Bercovici, D. Phys. Earth Planet. In. 236, 36–51 (2014).10. Davies, C. J. Phys. Earth Planet. In. 247, 65–79 (2015).11. Labrosse, S. Phys. Earth Planet. In. 247, 36–55 (2015).12. Nimmo, F. in Treatise on Geo-Physics 2nd edn (ed. Schubert, G.) 27–55 (Elsevier, Oxford, 2015).13. Olson, P. Science 342, 431–432 (2013).14. Hirose, K. et al. Nature 543, 99–102 (2017).15. O’Rourke, J. G. & Stevenson, D. J. Nature 529, 387–389 (2016).Du, A., Robinson, J.R., Rowan, J., Lazagabaster, I.A., Behrensmeyer, A.K., 2019. Stable carbon isotopes from paleosol carbonate and herbivore enamel document differing paleovegetation signals in the eastern African Plio-Pleistocene. Review of Palaeobotany and Palynology 261, 41-52. of stable carbon isotopes (δ13C) from herbivore dental enamel and paleosol carbonates are important tools for Plio-Pleistocene paleovegetation reconstructions. A single herbivore tooth documents an isotopic record of vegetation on the order of 10–1–1 years and in proportion to that individual's foraging range. Paleosol carbonates, conversely, record environmental information on longer time scales (102–3 years) but smaller spatial scales (101?m2). Given that these two proxies document paleoenvironments at different spatiotemporal scales, it is worth comparing them to see if they offer redundant or complementary paleovegetation information. Here, we compare δ13C patterns from herbivore enamel and paleosol carbonates from geological (sub)members in the Awash Valley, Ethiopia, and Turkana Basin, Kenya, from ~ 4.4–1 million years ago. We find that median herbivore enamel δ13C is typically ~ 5–7 per mil (‰) higher than that from paleosol carbonates within a given (sub)member. The distributions of paleosol carbonate δ13C values usually have less spread (variation) than herbivore enamel. The bias in median and spread between these two data types likely reflects the different spatial and temporal scales at which these proxies record paleoenvironmental information. Most Plio-Pleistocene fossiliferous deposits are formed in fluvial settings in which paleosol carbonates sample the immediate habitat of floodplain woodlands and shrubs, resulting in a lower δ13C (i.e., more C3) signal. On the other hand, fossil teeth of wide-ranging herbivores could generate a higher (i.e., more C4) and more variable δ13C signal if some taxa fed in floodplain woodlands while others fed on open grasslands distal to the floodplain. We conclude that δ13C values from herbivore enamel and paleosol carbonates offer paleovegetation data at different spatiotemporal scales, both of which are informative for hominin habitat reconstructions. Careful consideration of the spatial and temporal signals inherent in these and other proxies should be applied in future studies.Du, F., Ning, S., Liu, C., Li, C., Qiao, J., Tan, F., Luo, Z., 2019. Petrographical and geochemical characterization of the inertinite-rich coal from the Ningdong Coalfield, Northwest Ordos Basin, China. Arabian Journal of Geosciences 12, 36. study deals with the coal petrographical and geochemical characteristics of the #2 and #6 coal seams in the Ningdong Coalfield, Northwest Ordos Basin. Proximate analysis, sulfur forms, ash composition, trace element contents along with macral analysis, and X-ray diffraction were performed on the coal samples. The Ningdong coal was deposited in a large continental (freshwater) basin, which resulted in very low ash yield and total sulfur contents (7.63 and 0.35% on average, respectively), with organic sulfur being the dominant sulfur form. The average random vitrinite reflectance of #2 and #6 seams are 0.49 and 0.60%, respectively, indicating a low metamorphic grade. Inertinite is the most abundant group in the Ningdong coal (50.1% on average), whereas, the vitrinite and liptinite contents are 44.2 and 2.4%, on average, respectively. SiO2 is the major coal ash component (35.57%), whereas, the Al2O3, CaO, and Fe2O3 contents also exceed 10% of the crystalline phases. Trace element contents are low in general; a lot of them are less than the respective World hard coal values. At the same time, the contents of Sc, Cr, Mn, Cu, Y, La, Tl, Pb, Th, U, Cs, Yb, and Hf are close to the average values of the World hard coal, with Mn and Sr even slightly enriched in the #6 and #2 seam, respectively. Analysis shows that Si, Al, K, Ti, Li, Cr, Nb, Pb, Th, Cd, In, Hf, and Ta are mainly hosted in the exogenous minerals and Ca, Mg, and Na mainly come from the endogenous minerals. The flat and wide basin structure along with the paleomire supply with fresh water are the major reasons of the special petrographical and geochemical feature of the Ningdong coal.Duller, R.A., Armitage, J.J., Manners, H.R., Grimes, S., Jones, T.D., 2019. Delayed sedimentary response to abrupt climate change at the Paleocene-Eocene boundary, northern Spain. Geology 47, 159-162. routing systems (SRSs) are a critical element of the global response to ongoing climate change. However SRS response to climate forcing is complex, fragmentary, and obscured when viewed over short, human time scales (10?1–102 yr). Over long time scales (>102–103 yr), the aggregated, system-wide response of SRSs to climate forcing can be gleaned with more confidence from the sedimentary record, but the nature and time scales of this aggregated response to abrupt climate change are still poorly understood. Here, we investigate the aggregated temporal response of a SRS in northern Spain to abrupt climate warming at the Paleocene-Eocene thermal maximum (PETM). Our results show that terrestrial sites in northern Spain record a temporal lag of 16.5 ± 7.5 k.y. between the onset of the PETM, defined by an abrupt negative excursion in the δ13C profile, and the onset of coarse-grained deposition. Within the same SRS at a deep marine site 500 km to the west, we observe a temporal lag of 16.5 ± 1.5 k.y. using an age model that is independent of that used for the terrestrial sites. These results suggest that the aggregated, system-wide response of SRSs to present-day global warming—if we take the PETM as an appropriate modern-day analogue—may persist for many millennia into the future.Duncan, B., McKay, R., Bendle, J., Naish, T., Inglis, G.N., Moossen, H., Levy, R., Ventura, G.T., Lewis, A., Chamberlain, B., Walker, C., 2019. Lipid biomarker distributions in Oligocene and Miocene sediments from the Ross Sea region, Antarctica: Implications for use of biomarker proxies in glacially-influenced settings. Palaeogeography, Palaeoclimatology, Palaeoecology 516, 71-89. climate proxies enable climate and environmental reconstructions for regions where other paleoclimatic approaches are unsuitable. The Antarctic Cenozoic record consists of widely varying lithologies, deposited in rapidly changing depositional settings, with large lateral variations. Previous sedimentological and microfossil studies indicate that the incorporation of reworked older material frequently occurs in these sediments, highlighting the need for an assessment of biomarker distribution across a range of depositional settings and ages to assess the role reworking may have on biomarker-based reconstructions. Here, we compare sedimentary facies with the distribution of n-alkanes and hopanoids within a terrestrial outcrop, two glaciomarine cores and a deep sea core, spanning the Late Oligocene to Miocene in the Ross Sea. Comparisons are also made with n-alkane distributions in Eocene glacial erratics and Mesozoic Beacon Supergroup sediments, which are both potential sources of reworked material. The dominant n-alkane chain length shifts from n-C29 to n-C27 between the Late Eocene and the Oligocene. This shift is likely due to changing plant community composition and the plastic response of n-alkanes to climate cooling. Samples from glaciofluvial environments onshore, and subglacial and ice-proximal environments offshore are more likely to display reworked n-alkane distributions, whereas, samples from lower-energy, lacustrine and ice-distal marine environments predominantly yield immature/contemporaneous n-alkanes. These findings emphasise that careful comparisons with sedimentological and paleontological indicators are essential when applying and interpreting n-alkane-based and other biomarker-based proxies in glacially-influenced settings.Dzombak, D.A., 2018. Moving beyond forensic monitoring to understand and manage impacts of hydraulic fracturing for oil and gas development. Proceedings of the National Academy of Sciences 115, 13145-13147. PNAS, Woda et al. (1) present the results of a multidimensional investigation of the impacts of several hydraulically fractured shale gas wells on an aquifer and a hydrologically connected stream in a particular area in central Pennsylvania. The stream, Sugar Run, has been impacted by migration of methane into it. Sugar Run has inflow of groundwater from aquifers overlying the Marcellus Shale, which is relatively close to the land surface in the study area (e.g., one shale gas well of primary focus in the study is reported to intersect the Marcellus Shale at a depth of 997 m).Stream samples and groundwater samples were collected upstream and downstream from a location in Sugar Run where intermittent bubbling and groundwater seepage have been observed for at least 4 y since intensive shale gas development began in the study area in 2008. Samples were analyzed for dissolved methane; Na, Ca, Mg, Fe, Mn, SO42?, Cl?, and other inorganic solutes; carbon and strontium isotopes; and noble gases. The authors also obtained and analyzed regional groundwater-quality data and water-quality data for Sugar Run before shale gas development.Analysis of the water-quality data with consideration of regional characteristics and surface and groundwater characteristics before shale gas development led Woda et al. (1) to conclude from multiple lines of evidence that Sugar Run and the aquifer(s) that provide inflow to the stream have been contaminated by “new methane” mobilized by the shale gas development. They propose a water-quality indicator of the presence of recent methane contamination, namely, high sulfate (>6 mg/L) and iron (>0.3 mg/L) in waters with high methane concentrations. The protocol developed by the authors for use of aqueous geochemical conditions to identify impacts associated with new methane will be useful in the Marcellus region and, perhaps, in … Easson, C.G., Lopez, J.V., 2019. Depth-dependent environmental drivers of microbial plankton community structure in the northern Gulf of Mexico. Frontiers in Microbiology 9, 3175. doi: 10.3389/fmicb.2018.03175. Gulf of Mexico (GoM) is a dynamic marine ecosystem influenced by multiple natural and anthropogenic processes and inputs, such as the intrusion of warm oligotrophic water via the Loop Current, freshwater and nutrient input by the Mississippi River, and hydrocarbon inputs via natural seeps and industrial spills. Microbial plankton communities are important to pelagic food webs including in the GoM but understanding the drivers of the natural dynamics of these passively distributed microorganisms can be challenging in such a large and heterogeneous system. As part of the DEEPEND consortium, we applied high throughput 16S rRNA sequencing to investigate the spatial and temporal dynamics of pelagic microbial plankton related to several environmental conditions during two offshore cruises in 2015. Our results show dramatic community shifts across depths, especially between photic and aphotic zones. Though we only have two time points within a single year, observed temporal shifts in microbial plankton communities were restricted to the seasonally influenced epipelagic zone (0-200m), and appear mainly driven by changes in temperature. Environmental selection in microbial plankton communities was depth-specific, with variables such as turbidity, salinity, and abundance of photosynthetic taxa strongly correlating with community structure in the epipelagic zone, while variables such as oxygen and specific nutrient concentrations were correlated with community structure at deeper depths.Edvardsen, T., Rasmussen, J.A., Stemmerik, L., 2019. Testing of different disintegration methods for micropalaeontological analyses. Marine Micropaleontology 147, 12-15. different preparation methods have been tested in order to determine the most suitable for disintegration of chalk for micropalaeontological analysis. Several factors have been examined, including the extent of disintegration, time consumed, state of foraminiferal preservation, and diversity of foraminifera. For the sediments used in this study, we find that a combination of the modified Glauber's salt and detergent methods are the most successful, while the acid-hot water method may be better suited for extraction of larger fossils. The study shows that not only is the preservation influenced by the chosen preparation method but also environmental indices such as the planktic to benthic ratio.Ela, N.A., Tahoun, S.S., Fouad, T., Mousa, D.A., Saleh, R., 2018. Source rock evaluation of Kharita and Bahariya formations in some wells, North Western Desert, Egypt: Visual palynofacies and organic geochemical approaches. Egyptian Journal of Petroleum 27, 455-465. analyses were applied on ninety-one samples from the subsurface Albian – Cenomanian succession represented by Kharita and Bahariya formations, encountered in El-Noor, and South Sallum wells, located in the North Western Desert, Egypt, to visually characterize the content of dispersed organic matter, as well as, organic geochemical characterization to reveal the depositional paleoenvironments and source rock potentiality. The result recognized of five palynofacies associations in the studied interval. The deposition of Kharita Formation took place mainly in a steady and a relatively stable deltaic to marginal environment continued as well in the lower part of Bahariya Formation with minor changes. The marine influence became more common in the upper part of Bahariya Formation showing the exceptional high hydrocarbon potential recorded in the studied interval. This indicates marine transgression by the end of the early Cenomanian (Upper Bahariya) age. Samples from the Kharita Formation contain abundant brown phytoclasts which suggest gas-prone kerogen type III and IV. While Bahariya Formation includes translucent, brown cuticles and woody tracheid phytoclasts pointing to more promising gas-prone kerogen type III. The organic geochemical analysis shows poor to fair gas-prone source rock potential within the study section., Thermally, the color of the spore grains in Kharita and Bahariya formations show that dark yellow to orange, indicates immature besides their general little poor hydrocarbon generation potentiality.Eleyedath, A., Swamy, A.K., 2018. Prediction of density and viscosity of bitumen. Petroleum Science and Technology 36, 1779-1786. is well known fact that temperature and pressure significantly affects density and viscosity of bitumen. The present work utilizes Gene Expression Programming (GEP) approach to develop models to predict density and viscosity of bitumen. To evaluate the accuracy of proposed GEP based models, results reported by various researchers were utilized. This includes test results regarding Athabasca, Cold Lake and Gas free bitumen. The developed GEP based models were compared with the conventional empirical regression equations. The statistical analysis indicates that GEP based models work better than other existing models for density and viscosity of bitumen.Enayatpour, S., van Oort, E., Patzek, T., 2019. Thermal cooling to improve hydraulic fracturing efficiency and hydrocarbon production in shales. Journal of Natural Gas Science and Engineering 62, 184-201. hydrocarbon reserves contained in oil and gas shale formations are proving themselves to be abundant sources of current and future energy supply, unlocked through the technologies of horizontal drilling and hydraulic fracturing. Despite the various technology improvements that have buoyed the ”shale revolution” in the last decade, there remain very significant opportunities to further improve hydrocarbon recovery from shales by making hydraulic fracturing more efficient. In this paper, we look into the possibility of stimulating a rock matrix to a higher degree with hydraulic fractures by deliberately cooling down the rock. Cooling reduces in-situ thermal stress, which lowers initiation and propagation pressures of hydraulic fractures. Moreover, when a laterally confined solid undergoes temperature reduction induced by cooling, a thermal stress gradient is developed in the solid body. We perform sensitivity analyses to show that in an in-homogenous shale, this thermal stress gradient can lead to differential contraction of its various mineralogical constituents, which in turn may create thermal cracks. The opening of such cracks increases shale permeability and provides additional pathways for the flow of hydrocarbons, thereby enhancing productivity. Here, we solve the coupled equations of stress, heat transfer and flow using finite element techniques for hydraulic stimulation amplified by cooling. It is shown that thermal cracks in tight formations induced by thermal cooling have the potential to improve the productivity of horizontal wellbores placed in shale by an estimated 16% for the case of methane gas flow through thermally stimulated shale of micro-darcy permeability.Enge, A.J., Wanek, W., Heinz, P., 2018. Preservation effects on isotopic signatures in benthic foraminiferal biomass. Marine Micropaleontology 144, 50-59. samples for stable isotope analysis are frequently preserved after field collection or during cruises despite the lack of knowledge if and how preservation changes the elemental and stable isotope composition of the protists. Thus, the aim of this study was to investigate the effects of preservation on natural and stable isotope-enriched foraminifera. We tested the following preservation methods on specimens of the benthic foraminifer Ammonia sp. (without surrounding sediment): drying at room temperature, freezing (?25?°C in seawater), ethanol with and without Rose Bengal (RB), and formalin with and without RB. Natural specimens were preserved for 14, 90, and 240?days, while stable isotope-enriched specimens were preserved for 30?days following a pulse-chase feeding experiment. Regardless of type and length, preservation caused a significant loss of carbon (biomass) of up to 42% and lower nitrogen contents in most treatments. Already preservation for 14?days significantly affected δ13C and δ15N signatures, with the strongest shifts caused by freezing at ?25?°C in seawater and formalin fixation (with RB). With longer preservation time, the gap between foraminiferal δ13C signatures and the control signal increased for all preservation methods except for 96% ethanol. The observed shifts in the δ13C signatures in the differently preserved foraminifera are in a range of shifts that are found in the signatures of natural foraminifera and are caused by the uptake of various food sources. Applying different preservation methods therefore can bias trophic interpretations based on natural isotope abundances. Preservation of stable isotope-enriched foraminifera in ethanol (with and without RB) resulted in significantly lower carbon uptake estimates, while freezing caused significantly lower nitrogen uptake estimates. Our findings suggest that, if possible, any storage or preservation should be avoided, especially in formalin or at ?25?°C with seawater; otherwise storage should be kept as short as possible. Of all tested methods, drying foraminifera at room temperature was the least affecting method with comparatively low variation among replicates. Comparison of biomass, isotope signatures and uptake estimates obtained from differently preserved specimens should be considered carefully, as differences might not be caused naturally, but by alterations of the cytoplasm during preservation.English, N.J., Allen, C.C.R., 2019. Magnetic-field effects on methane-hydrate kinetics and potential geophysical implications: Insights from non-equilibrium molecular dynamics. Science of The Total Environment 661, 664-669. have conducted non-equilibrium molecular-dynamics (NEMD) simulation to show that externally-applied magnetic fields, including their reversals in direction, have important effects on gas-release dynamics from methane hydrates. In particular, we apply fluctuation-dissipation analysis in the guise of Onsager's hypothesis to study hydrate kinetics at lower applied-field intensities, including temporary hydrate destabilisation in the wake of field-polarity switch; we scale down to the lowest practicable field intensities, of the order of 1?T. We conjecture, that these NEMD-based findings, particularly those involving polarity switch, may have ramifications for superchron-related Earth's magnetic-field polarity swaps affecting methane release into the geosphere, although a good deal of further work would be needed to provide a more definitive causal link.Esteves, A.M., Gra?a, G., Peyriga, L., Torcato, I.M., Borges, N., Portais, J.-C., Santos, H., 2019. Combined transcriptomics–metabolomics profiling of the heat shock response in the hyperthermophilic archaeon Pyrococcus furiosus. Extremophiles 23, 101-118. furiosus is a remarkable archaeon able to grow at temperatures around 100?°C. To gain insight into how this model hyperthermophile copes with heat stress, we compared transcriptomic and metabolomic data of cells subjected to a temperature shift from 90?°C to 97?°C. In this study, we used RNA-sequencing to characterize the global variation in gene expression levels, while nuclear magnetic resonance (NMR) and targeted ion exchange liquid chromatography–mass spectrometry (LC–MS) were used to determine changes in metabolite levels. Of the 552 differentially expressed genes in response to heat shock conditions, 257 were upregulated and 295 were downregulated. In particular, there was a significant downregulation of genes for synthesis and transport of amino acids. At the metabolite level, 37 compounds were quantified. The level of di-myo-inositol phosphate, a canonical heat stress solute among marine hyperthermophiles, increased considerably (5.4-fold) at elevated temperature. Also, the levels of mannosylglycerate, UDP-N-acetylglucosamine (UDPGlcNac) and UDP-N-acetylgalactosamine were enhanced. The increase in the pool of UDPGlcNac was concurrent with an increase in the transcript levels of the respective biosynthetic genes. This work provides the first metabolomic analysis of the heat shock response of a hyperthermophile.Estrada, C.F., Sverjensky, D.A., Hazen, R.M., 2019. Selective adsorption of aspartate facilitated by calcium on brucite [Mg(OH)2]. ACS Earth and Space Chemistry 3, 1-7. ions present in an aqueous environment may significantly improve biomolecule attachment at mineral surfaces through the formation of cooperative surface complexes. To test whether this phenomenon results in the selective adsorption of an organic species, we conducted batch adsorption experiments with an equimolar mixture of the amino acids aspartate, glycine, lysine, leucine, and phenylalanine onto powdered brucite [Mg(OH)2] at pH 10.2. We performed the batch experiments in triplicate both without and with 4.1 mM CaCl2. In experiments without CaCl2, we observed that up to 0.7 μmol m–2 of aspartate and about 0.4 μmol m–2 each of the remaining four amino acids adsorbed onto brucite. When we added CaCl2, we found that up to 1.6 μmol m–2 of aspartate selectively adsorbed onto the brucite surface relative to between 0.2 and 0.3 μmol m–2 of the other amino acids. We measured the brucite particle surface charge to be slightly positive without added CaCl2, but the surface charge becomes significantly more positive in the presence of CaCl2. Our results suggest that negatively charged molecules selectively and cooperatively adsorb onto brucite when CaCl2 is added to the system. This study emphasizes the importance of the dissolved ionic profile of a geochemical environment when evaluating the role of mineral surfaces in the evolution of prebiotic chemistry. The presence of dissolved ions at a mineral–water interface can selectively enhance the adsorption and concentration of specific molecules, which may serve as a key process in molecular self-organization and the assembly of proteins that are composed of metal–ligand complexes.Etourneau, J., Sgubin, G., Crosta, X., Swingedouw, D., Willmott, V., Barbara, L., Houssais, M.-N., Schouten, S., Sinninghe Damsté, J.S., Goosse, H., Escutia, C., Crespin, J., Massé, G., Kim, J.-H., 2019. Ocean temperature impact on ice shelf extent in the eastern Antarctic Peninsula. Nature Communications 10, Article 304. recent thinning and retreat of Antarctic ice shelves has been attributed to both atmosphere and ocean warming. However, the lack of continuous, multi-year direct observations as well as limitations of climate and ice shelf models prevent a precise assessment on how the ocean forcing affects the fluctuations of a grounded and floating ice cap. Here we show that a +0.3–1.5?°C increase in subsurface ocean temperature (50–400?m) in the northeastern Antarctic Peninsula has driven to major collapse and recession of the regional ice shelf during both the instrumental period and the last 9000 years. Our projections following the representative concentration pathway 8.5 emission scenario from the Fifth Assessment Report of the Intergovernmental Panel on Climate Change reveal a +0.3?°C subsurface ocean temperature warming within the coming decades that will undoubtedly accelerate ice shelf melting, including the southernmost sector of the eastern Antarctic Peninsula.Fan, C., He, S., Zhang, Y., Qin, Q., Zhong, C., 2018. Development phases and mechanisms of tectonic fractures in the Longmaxi Formation Shale of the Dingshan area in southeast Sichuan Basin, China. Acta Geologica Sinica - English Edition 92, 2351-2366. gas has currently attracted much attention during oil and gas exploration and development. Fractures in shale have an important influence on the enrichment and preservation of shale gas. This work studied the developmental period and formation mechanism of tectonic fractures in the Longmaxi Formation shale in the Dingshan area of southeastern Sichuan Basin based on extensive observations of outcrops and cores, rock acoustic emission (Kaiser) experiments, homogenization temperature of fracture fill inclusions, apatite fission track, thermal burial history. The research shows that the fracture types of the Longmaxi Formation include tectonic fractures, diagenetic fractures and horizontal slip fractures. The main types are tectonic high‐angle shear and horizontal slip fractures, with small openings, large spacing, low densities, and high degrees of filling. Six dominant directions of the fractures after correction by plane included NWW, nearly SN, NNW, NEE, nearly EW and NW. The analysis of field fracture stage and fracture system of the borehole suggests that the fractures in the Longmaxi Formation could be paired with two sets of plane X‐shaped conjugate shear fractures, i.e., profile X‐shaped conjugate shear fractures and extension fractures. The combination of qualitative geological analysis and quantitative experimental testing techniques indicates that the tectonic fractures in the Longmaxi Formation have undergone three periods of tectonic movement, namely mid‐late Yanshanian movement (82–71.1 Ma), late Yanshanian and middle Himalaya movements (71.1–22.3 Ma), and the late Himalayan movement (22.3–0 Ma). The middle‐late period of the Yanshanian movement and end of the Yanshanian movement‐middle period of the Himalayan movement were the main fracture‐forming periods. The fractures were mostly filled with minerals, such as calcite and siliceous. The homogenization temperature of fracture fill inclusions was high, and the paleo‐stress value was large; the tectonic movement from the late to present period was mainly a slight transformation and superposition of existing fractures and tectonic systems. Based on the principle of tectonic analysis and theory of geomechanics, we clarified the mechanism of the fractures in the Longmaxi Formation, and established the genetic model of the Longmaxi Formation. The research on the qualitative and quantitative techniques of the fracture‐phase study could be effectively used to analyze the causes of the marine shale gas fractures in the Sichuan Basin. The research findings and results provide important references and technical support for further exploration and development of marine shale gas in South China.Fan, C., Tang, X., Zhang, Y., Song, Y., Jiang, Z., Luo, Q., Li, B., 2018. Characteristics and formation mechanisms of tight oil: A case study of the Huahai Depression, Jiuquan Basin, Northwest China. Energy Exploration & Exploitation 37, 296-314. exploration of tight oil reservoirs has achieved a big success, especially in the Huahai Depression, Jiuquan Basin, China, but the characteristics and formation mechanisms of the tight oil reservoir are unclear. In this paper, a series of analyses including thin section, scanning electron microscope, gas chromatography–mass spectrometry, isotope, and fluid inclusions were taken to study the tight reservoirs of the Xiagou Formation (K1g) and Zhonggou Formation (K1z) in the Huahai Depression. The results show that the main factors influencing the porosity and permeability of the tight reservoir are the compaction and two periods of carbonate cementation. The second type of carbonate cementation was related to the decarboxylation of organic acids in parts of the study area. The tight oil accumulation periods for different formations are confirmed, during 115–102 Ma in K1g1, 114–97 Ma in K1g2, and 103–85 Ma in K1z1, respectively. The tight oil migrations are executed for only several meters vertically but hundreds of meters even kilometers laterally. Two kinds of formation mechanisms exist in the study area. The main formation pattern is the “hydrocarbon accumulated after reservoir had tightened,” which has occurred in most of the study area. The other pattern, the “hydrocarbon accumulated during reservoir was tightening,” is found in several places of the study area.Fang, H., Sang, S., Liu, S., Liu, S., 2019. Experimental simulation of replacing and displacing CH4 by injecting supercritical CO2 and its geological significance. International Journal of Greenhouse Gas Control 81, 115-125. technology for the replacement and displacement of CH4 by supercritical CO2 (Sc-CO2-ECBM) injection is still in its infancy, so experimental simulation and theoretical studies on this Sc-CO2-ECBM technology should be perfected. First, experimental simulations of the Sc-CO2-ECBM process were carried out under different temperatures, injected pressures and confining pressures. Then, the differences in replacement and displacement efficiency and the equivalent percentage of replacement and displacement time between samples were analyzed. Last, the influences of the pore network model on the difference in the replacement and displacement effects, the stage division and its difference of the replacement and displacement effects, and the project design of collaborative optimization of Sc-CO2storage and ECBM were discussed. The results show the following: (1) The injected pressure, confining pressure and temperature were the key factors affecting the replacement and displacement efficiency. The equivalent percentage of replacement and displacement time negatively correlated with the differential pressure and temperature was positively correlated with the confining pressure, but the replacement and displacement efficiencies were the opposite. (2) The pore network model and its characteristic parameters explain that the replacement and displacement effects were more successful in the SH sample than that in the YW sample. (3) According to the gas condition at the outlet of the sample chamber, the replacement and displacement process can be divided into 3 stages. ① Sc-CO2 was not detected, and the replacement effect was dominant. ② Sc-CO2 and CH4 were detected simultaneously, and the gas concentration was constantly changing, as the process changed from replacement to displacement. ③ Sc-CO2 and CH4 were detected simultaneously, the gas concentration tended to be stable, and the displacement effect was dominant. (4) The geological significance of this experimental simulation is that the Sc-CO2-ECBM process can be embodied by the optimization design of the Sc-CO2 project, ECBM project and Sc-CO2 and ECBM project. This research into experimental simulation of the Sc-CO2-ECBM process can further promote the implementation of the CO2-ECBM project in deep coal seams.Fang, Q., Wu, H., Wang, X., Yang, T., Li, H., Zhang, S., 2019. An astronomically forced cooling event during the Middle Ordovician. Global and Planetary Change 173, 96-108. cooling trend during the Middle Ordovician may have resulted in significant biotic, atmospheric and hydrologic changes, but the exact timing and forcing of this climate event still remain largely ambiguous. Here, we present astronomically calibrated magnetic susceptibility (MS) and gamma ray (GR) data from the shale and carbonate successions of the Kalpin area in the Tarim Basin, NW China to study the Middle Ordovician climate. The spectral analyses of the 405-kyr calibrated MS and GR time series reveal periodicities close to 405 (calibrated), 100, 31 and 19 kyr, supporting a Milankovitch forcing for the sedimentary cyclicity. The eccentricity and obliquity amplitude modulation cycles show main periodicities of ~2.4 and ~1.2 Myr, respectively. A cooling event along with the middle Darriwilian isotope carbon excursion (MDICE) appears to have been initiated by the alignment of the eccentricity and obliquity amplitude minima at 4.07 Myr prior to the Darriwilian/Sandbian (D/S) boundary. This climate event was in pace with high-amplitude obliquity oscillations during a period when the 1.2 Myr obliquity amplitude modulation cycles controlled the global third-order eustatic sequences. The termination of this cooling event corresponding to a global third-order highstand was initiated by an eccentricity oscillation maximum at 0.63 Myr prior to the D/S boundary. Subsequent climate alleviation was dominated by eccentricity forcing until the earliest Sandbian. We suggest that although the climate changes have been primarily associated with the CO2 level, a specific sequence of astronomical variations during the Middle Ordovician was responsible for the time when the critical threshold was crossed.Fang, Q., Zhu, D., Agarkova, I., Adhikari, J., Klose, T., Liu, Y., Chen, Z., Sun, Y., Gross, M.L., Van Etten, J.L., Zhang, X., Rossmann, M.G., 2019. Near-atomic structure of a giant virus. Nature Communications 10, Article 388. the nucleocytoplasmic large DNA viruses (NCLDVs) are one of the largest group of viruses that infect many eukaryotic hosts, the near-atomic resolution structures of these viruses have remained unknown. Here we describe a 3.5?? resolution icosahedrally averaged capsid structure of Paramecium bursaria chlorella virus 1 (PBCV-1). This structure consists of 5040 copies of the major capsid protein, 60 copies of the penton protein and 1800 minor capsid proteins of which there are 13 different types. The minor capsid proteins form a hexagonal network below the outer capsid shell, stabilizing the capsid by binding neighboring capsomers together. The size of the viral capsid is determined by a tape-measure, minor capsid protein of which there are 60 copies in the virion. Homologs of the tape-measure protein and some of the other minor capsid proteins exist in other NCLDVs. Thus, a similar capsid assembly pathway might be used by other NCLDVs.Fauziah, C.A., Al-Yaseri, A.Z., Beloborodov, R., Siddiqui, M.A.Q., Lebedev, M., Parsons, D., Roshan, H., Barifcani, A., Iglauer, S., 2019. Carbon dioxide/brine, nitrogen/brine, and oil/brine wettability of montmorillonite, illite, and kaolinite at elevated pressure and temperature. Energy & Fuels 33, 441-448. of CO2/brine/clay is one of the most important parameters in assessing CO2 storage capacities and containment security. Despite its importance, the literature data in this context are very limited. We thus systematically measured montmorillonite, illite, and kaolinite wettability for CO2/brine, nitrogen/brine, and nitrogen/oil systems at various pressures (5, 10, 15, and 20 MPa) and temperatures (305 and 333 K). The zeta potential of each clay mineral was also measured to investigate its link to the macroscopic contact angle. The results show that both advancing and receding water contact angles for CO2/brine, nitrogen/brine, and nitrogen/oil systems increase with an increase in pressure. However, they are only slightly reduced by increasing temperature. It was also shown that montmorillonite has a higher water contact angle in the presence of CO2, followed by illite and kaolinite. The same trend was measured for nitrogen/brine and brine/oil systems. Consequently, montmorillonite is strongly oil-wet; kaolinite and illite, however, are strongly water-wet at typical storage conditions (high pressure and elevated temperature). This has important implications for CO2 geostorage in determining the flow of CO2 and its entrapment, fluid spreading, and dynamics in the reservoir.Feng, Q., Xu, S., Wang, S., Li, Y., Gao, F., Xu, Y., 2019. Apparent permeability model for shale oil with multiple mechanisms. Journal of Petroleum Science and Engineering 175, 814-827. apparent permeability (AP) model for oil transport in shale must consider natural fractures and micro/nano-pores within organic matter and inorganic matrix. Furthermore, the effect of pore geometry, tortuosity, pore size distribution (PSD), the spatial distribution of different pores, total organic content (TOC), and liquid slip should also be taken into account. However, all of the aforementioned factors are not simultaneously considered in one AP model. In this work, we develop an AP model in 3D for shale oil to overcome this drawback. We first validate our model by comparing with the published data. Then sensitivity analysis for some parameters is investigated. After that, shale oil APs are used in a macro-scale reservoir simulation model. In this way, the effect of some micro-scale factors on production performance can be quantitatively evaluated. Notably, on the basis of embedded discrete fracture model (EDFM), our reservoir simulation model considers non-linear flow in shale matrix, complex hydraulic fracture geometry, and pressure-dependent permeability of hydraulic fractures. Results show that natural fractures contribute the most to AP, followed by organic pores and inorganic pores. In general, the AP in the horizontal direction is approximately twice that in the vertical direction in shale. Furthermore, the maximum error caused by the pore type on shale oil production is ～31%, followed by tortuosity (～25%), pore shape (～13%) and slip effect (～4.8%). In conclusion, it is necessary to simultaneously incorporate the influences of the aforementioned factors. Our stochastic permeability model can serve as an efficient tool to determine shale oil AP.Feng, W., Qiao, J., Li, D., Qi, L., 2019. Chiral ligand exchange capillary electrochromatography with dual ligands for enantioseparation of D,L-amino acids. Talanta 194, 430-436. block copolymers as coatings, a protocol of chiral ligand exchange capillary electrochromatography (CLE-CEC) protocol was designed and developed with dual ligands for D,L-amino acids enantioseparation. Four block copolymers including poly maleic anhydride-co-styrene-co-N-methacryloyl-L-histidine methyl ester [P(MAn-St-MAH)], poly maleic anhydride-co-styrene-co-N-methacryloyl-L-lysine methyl ester [P(MAn-St-MAL)], poly maleic anhydride-co-styrene-co-N-methacryloyl-L-phenylalanine methyl ester [P(MAn-St-MAP)] and poly maleic anhydride-co-styrene-co-N-methacryloyl-L-threonine methyl ester [P(MAn-St-MAT)] were synthesized by reversible addition fragmentation chain transfer polymerization reaction. Key factors affecting the enantioresolution were optimized, including the concentration of Zn (II) central ion, pH value of buffer solution and monomers of the block copolymers. The enantioresolution of the proposed CLE-CEC system could be enhanced dramatically by employing P(MAn-St-MAH) as the immobilized chiral ligand and by coordinating the synergistic effect of free ligand in buffer solution. The principle of improved enantioresolution of the CLE-CEC system with dual ligands was discussed. Well enantioseparation was successfully realized with 7 pairs of D,L-amino acids enantiomers baseline separation and 5 pairs part separation. For quantitative analysis of D,L-alanine, a good linearity was established in the range of 9.4?μM to 1.5?mM (r2 =?0.997) with the limits of detection (LODs) 3.7?μM of D-alanine, 2.0?μM for L-alanine, and limits of quantification (LOQs) 9.0?μM for D-alanine and 6.0?μM for L-alanine. The peak area and migration time reproducibility (n?=?6) were 4.1% and 3.5% for D-alanine, 3.7% and 3.1% for L-alanine. Further, the enzyme kinetics study of alanine aminotransferase was investigated with the constructed CLE-CEC system.Feng, X., Zhao, C., D'Andrea, W.J., Liang, J., Zhou, A., Shen, J., 2019. Temperature fluctuations during the Common Era in subtropical southwestern China inferred from brGDGTs in a remote alpine lake. Earth and Planetary Science Letters 510, 26-36. climate change over the past 2000 years, or the Common Era, is critical to understand how the climate system evolved from one controlled by natural forcings alone to one influenced by anthropogenic greenhouse gas forcing. However, global and regional temperature changes during this interval are still poorly understood, largely due to the limited geographical coverage and scarcity of data. Here we report a well-dated, quantitative, mean annual air temperature (MAAT) record with ～10-yr resolution for the Common Era derived from a sediment core collected at a small alpine lake in remote subtropical southwestern China, and based on a site-specific temporal calibration between down-core analyses of brGDGTs and instrumental data for the interval 1959–2015 AD. The record reveals distinct multicentennial-scale temperature fluctuations, including a relatively cold interval from 0–800 AD, followed by warmer temperatures during the so-called Medieval Climate Anomaly (MCA; 800–1400 AD), cooling during the Little Ice Age (LIA; 1400–1900 AD), and abrupt and rapid warming into the late-20th-century after 1900 AD. Superimposed on these large-scale features are three short-term cold events, centered on 250–310 AD (～0.06°C), 570–650 AD (～0.87°C), and 1800–1823 AD (～0.83°C), respectively. The temperature variations captured in the record are supported by historical documents and existing regional and global paleoclimate records, and correspond in time to a number of the major Chinese dynastic transitions. Importantly, the record captures large-magnitude (up to 4°C) centennial-scale temperature fluctuations, documents cold conditions during the first millennium AD, and demonstrates that the post-1989 AD warmth is greater than any other time during the past 2000 years. The results suggest that high-elevation areas have been more sensitive than low-elevation regions to climate variations during the Common Era.Fernández, R., Garate, J., Martín-Saiz, L., Galetich, I., Fernández, J.A., 2019. Matrix sublimation device for MALDI mass spectrometry imaging. Analytical Chemistry 91, 803-807. is a widely used method for matrix deposition in imaging mass spectrometry experiments. Still, most of the time, standard glass sublimators are used for this purpose, which do not enable optimal matrix deposition reproducibility, compromising inter-experiment comparison of the results. Here, we present an in-house designed stainless steel sublimator in which the parameters that have the strongest influence over matrix deposition reproducibility can be easily monitored. Using sections of human colon biopsies, we demonstrate the capabilities of this new prototype.Fielding, C.R., Frank, T.D., McLoughlin, S., Vajda, V., Mays, C., Tevyaw, A.P., Winguth, A., Winguth, C., Nicoll, R.S., Bocking, M., Crowley, J.L., 2019. Age and pattern of the southern high-latitude continental end-Permian extinction constrained by multiproxy analysis. Nature Communications 10, Article 385. studies of the end-Permian extinction (EPE), the largest biotic crisis of the Phanerozoic, have not resolved the timing of events in southern high-latitudes. Here we use palynology coupled with high-precision CA-ID-TIMS dating of euhedral zircons from continental sequences of the Sydney Basin, Australia, to show that the collapse of the austral Permian Glossopteris flora occurred prior to 252.3?Ma (~370 kyrs before the main marine extinction). Weathering proxies indicate that floristic changes occurred during a brief climate perturbation in a regional alluvial landscape that otherwise experienced insubstantial change in fluvial style, insignificant reorganization of the depositional surface, and no abrupt aridification. Palaeoclimate modelling suggests a moderate shift to warmer summer temperatures and amplified seasonality in temperature across the EPE, and warmer and wetter conditions for all seasons into the Early Triassic. The terrestrial EPE and a succeeding peak in Ni concentration in the Sydney Basin correlate, respectively, to the onset of the primary extrusive and intrusive phases of the Siberian Traps Large Igneous Province.Flanagan, G., Andrianova, A.A., Casey, J., Hellrung, E., Diep, B.A., Seames, W.S., Kubátová, A., 2019. Simultaneous high-temperature gas chromatography with flame ionization and mass spectrometric analysis of monocarboxylic acids and acylglycerols in biofuels and biofuel intermediate products. Journal of Chromatography A 1584, 165-178., diacyl- and monoacylglycerols (TAGs, DAGs, MAGs) along with monocarboxylic acids (MCAs) are intermediate products in many triacylglycerol oil-to-biofuel conversion pathways. Accumulation of these compounds leads to poor biofuel characteristics and may result in fuel system damage. We developed a method for simultaneous identification and quantification of a wide range of MCAs (C4-C18), MAGs, DAGs, and TAGs. The method is based on trimethylsilylation followed by high temperature GC with programmed temperature vaporizer (PTV) injection coupled to parallel FID and MS detectors (HTGC-FID/MS).To minimize the discrimination of both low and high molecular weight species typically occurring on the injector, we optimized injection conditions using a central composite design. The critical variables were the time at initial temperature (40?°C), splitless time, and the interaction between these two parameters. Among three tested electron ionization source/quadrupole analyzer temperatures, a 350/200?°C setting provided the highest response and signal-to-noise ratio for TAGs and did not have an effect on MAGs and DAGs.Similar results were obtained when quantifying target analytes in intermediate products of soybean oil cracking with FID and MS (using specific acylglycerol fragmentation ions). The instrumental FID limits of detection (LODs) were 0.07–0.27?ng for most of the target analytes. Selected ion monitoring (SIM) LODs were 0.01–0.05?ng for MCAs and 0.03–0.14?ng for acylglycerols. For the total ion current (TIC), LODs observed increased with acyl chain length and degree of unsaturation, resulting in an increase from 0.05 to 0.18?ng for MCAs (C5 to C18) and from 0.03 to 1.8?ng for acylglycerols (TAGs C8 to C22). Deviations in the repeatability of sample preparation, intra- and inter-day analyses, including sample stability over an eight-day time period, did not exceed 10% variance. These results demonstrate that the developed method is accurate and robust for the determination of acylglycerols and MCAs produced during the processing of TAGs into biofuels.Floyd, M.A.M., Williams, A.J., Grubisic, A., Emerson, D., 2018. Metabolic processes preserved as biosignatures in iron-oxidizing microorganisms: Implications for biosignature detection on Mars. Astrobiology 19, 40-52. bacteria occupy a distinct environmental niche. These chemolithoautotrophic organisms require very little oxygen (when neutrophilic) or outcompete oxygen for access to Fe(II) (when acidophilic). The utilization of Fe(II) as an electron donor makes them strong analog organisms for any potential life that could be found on Mars. Despite their importance to the elucidation of early life on, and potentially beyond, Earth, many details of their metabolism remain unknown. By using on-line thermochemolysis and gas chromatography–mass spectrometry (GC-MS), a distinct signal for a low-molecular-weight molecule was discovered in multiple iron-oxidizing isolates as well as several iron-dominated environmental samples, from freshwater and marine environments and in both modern and older iron rock samples. This GC-MS signal was neither detected in organisms that did not use Fe(II) as an electron donor nor present in iron mats in which organic carbon was destroyed by heating. Mass spectral analysis indicates that the molecule bears the hallmarks of a pterin-bearing molecule. Genomic analysis has previously identified a molybdopterin that could be part of the electron transport chain in a number of lithotrophic iron-oxidizing bacteria, suggesting one possible source for this signal is the pterin component of this protein. The rock samples indicate the possibility that the molecule can be preserved within lithified sedimentary rocks. The specificity of the signal to organisms requiring iron in their metabolism makes this a novel biosignature with which to investigate both the evolution of life on ancient Earth and potential life on Mars.Fosu, B.R., Ghosh, P., Mishra, D., Banerjee, Y., K, P., Sarkar, A., 2019. Acid digestion of carbonates using break seal method for clumped isotope analysis. Rapid Communications in Mass Spectrometry 33, 203-214.: Acid digestion of carbonates to release CO2 is a crucial and sensitive step in sample preparation for clumped isotope analysis. In addition to data reduction and instrumental artefacts, many other uncertainties in the clumped isotope analysis of carbonates arise from the method used for the preparation of CO2. We describe here an in‐house‐designed reaction vessel that circumvents degassing and contamination problems commonly associated with the McCrea‐type digestion protocols. Methods: We designed a leak‐free break seal reaction vessel (made of Pyrex?) suitable for prolonged acid digestion at 25°C. Using this new vessel, several carbonate reference materials widely used in the clumped isotope community and other in‐house laboratory standards were acid‐digested and analysed for their δ13C, δ18O and Δ47 values with a dual inlet MAT 253 isotope ratio mass spectrometer following standard gas chromatography purification and data evaluation protocols. Results: Long‐term reproducibility in Δ47 determination was established using international references and in‐house working standards as follows (mean and SE): Carrara‐1 (0.395?±?0.002‰, n?=?43), Carrara‐2 (0.441?±?0.003‰, n?=?22), OMC (0.587?±?0.004‰, n?=?16), NBS 19 (0.393?±?0.005‰, n?=?10), NBS 18 (0.473?±?0.003‰, n?=?5), ETH 1 (0.271?±?0.005‰, n?=?7), ETH 3 (0.698?±?0.005‰, n?=?3), MZ (0.715?±?0.002‰, n?=?3) and several others. Conclusions: A new method using a break seal tube was found to be efficient for the clumped isotope analysis of carbonates that require longer reaction time at 25°C. This method yields good precision in Δ47 analysis and was found to be suitable for acid digestions at any desired temperature. Frena, M., Santos, A.P.S., Souza, M.R.R., Carvalho, S.S., Madureira, L.A.S., Alexandre, M.R., 2019. Sterol biomarkers and fecal coliforms in a tropical estuary: Seasonal distribution and sources. Marine Pollution Bulletin 139, 111-116. Sergipe River estuary has been subjected to a range of anthropogenic activities including food, plastic, textile, ceramic and metallurgical production plants along with domestic sewage inputs, all of which are of environmental concern. In this study, the levels of fecal coliforms (FC) in surface water samples and sterols in superficial sediment samples collected from the Sergipe River estuary were determined. Based on the FC concentrations, 58% of the water samples were considered Water Potentially Unusable (WPU) according to the United States Environmental Protection Agency (USEPA). Concentrations of coprostanol ranged from 13 to 1072?ng?g?1, indicating a significant input of sewage at some points in the estuary. Principal Component Analysis (PCA) showed that there is no clear correlation between the coprostanol and coliform data, which may be due to the high resistance to degradation of coprostanol in sediments and to recent inputs of sewage at the water sample collection points.Frey, R., Hayashi, T., Buller, R.M., 2019. Directed evolution of carbon–hydrogen bond activating enzymes. Current Opinion in Biotechnology 60, 29-38. industrial biocatalysis is maturing, access to enzymatic activities beyond chiral resolutions, asymmetric ketone reductions and reductive aminations is gradually becoming reality. Especially the utilization of carbon–hydrogen bond (C–H) activating enzymes is very attractive as they catalyze a variety of chemically extremely challenging transformations. Because of their intrinsic complexity, the use of these enzymes in manufacturing has been limited. However, recent advances in enzyme engineering and bioinformatics have led to activity improvements for native and non-native substrates, the introduction of new-to-nature chemistries and the identification of promising novel enzyme families. Looking forward, the use of automation and advanced computer algorithms will help to streamline the evolution process of C–H activating enzymes leading to more robust and active biocatalysts.Friedrich, A.M., 2019. Palaeogeological hiatus surface mapping: a tool to visualize vertical motion of the continents. Geological Magazine 156, 308-319. topography is a well-established consequence of global geodynamic models of mantle convection with horizontal dimensions of &gt;1000 km and amplitudes up to 2 km. Such physical models guide the interpretation of geological records on equal dimensions. Continent-scale geological maps therefore serve as reference frames of choice to visualize erosion/non-deposition as a proxy for long-wavelength, low-amplitude vertical surface motion. At a resolution of systems or series, such maps display conformable and unconformable time boundaries traceable over hundreds to thousands of kilometres. Unconformable contact surfaces define the shape and size of time gap (hiatus) in millions of years based on the duration of time represented by the missing systems or series. Hiatus for a single system or series base datum diminishes laterally to locations (anchor points) where it is conformable at the mapped resolution; it is highly dependent upon scale. A comparison of hiatus area between two successive system or series boundaries yields changes in location, shape, size and duration, indicative of the transient nature of vertical surface motion. As a single-step technique, it serves as a quantitative proxy for palaeotopography that can be calibrated using other geological data. The tool magnifies the need for geological mapping at the temporal resolution of stages, matching process rates. The method has no resolving power within conformable regions (basins) but connects around them. When applied to marine seismic sections that relate to rock record, not to time, biostratigraphic and radiometric data from deep wells are needed before hiatus areas – that relate to time – can be mapped.Friedrich, J.M., McLain, H.L., Dworkin, J.P., Glavin, D.P., Towbin, W.H., Hill, M., Ebel, D.S., 2019. Effect of polychromatic X-ray microtomography imaging on the amino acid content of the Murchison CM chondrite. Meteoritics & Planetary Science 54, 220-228.‐ray microcomputed tomography (μCT) is a useful means of characterizing cosmochemical samples such as meteorites or robotically returned samples. However, there are occasional concerns that the use of μCT may be detrimental to the organic components of a chondrite. Small organic compounds such as amino acids comprise up to ~10% of the total solvent extractable carbon in CM carbonaceous chondrites. We irradiated three samples of the Murchison CM carbonaceous chondrite under conditions akin to and harsher than those typically used during typical benchtop X‐ray μCT imaging experiments to determine if detectable changes in the amino acid abundance and distribution relative to a nonexposed Murchison control sample occurred. After subjecting three meteorite samples to ionizing radiation dosages between ~300 Gray (Gy) and 3 kGy with bremstrahlung X‐rays, we analyzed the amino acid content of each sample. Within sampling and analytical errors, we cannot discern differences in the amino acid abundances and amino acid enantiomeric ratios when comparing the control samples (nonexposed Murchison) and the irradiated samples. We conclude that a polychromatic X‐ray μCT experiment does not alter the abundances of amino acids to a degree greater than how well those abundances are measured with our techniques and therefore any damage to amino acids is minimal.Fu, L.-l., Ding, H., Han, L.-f., Jia, L., Yang, W.-z., Zhang, C.-x., Hu, Y., Zuo, T.-t., Gao, X.-m., Guo, D.-a., 2019. Simultaneously targeted and untargeted multicomponent characterization of Erzhi Pill by offline two-dimensional liquid chromatography/quadrupole-Orbitrap mass spectrometry. Journal of Chromatography A 1584, 87-96. targeted and untargeted metabolites characterization can be achieved by feat of different liquid chromatography/mass spectrometry (LC–MS) platforms by multiple MS experiments or using data-independent acquisition followed by precursor-product ions matching based on certain algorithms. The resulting insufficiency in efficiency and availability greatly restricts the applicability of these strategies in large-scale profiling and identification of various metabolites. A strategy simultaneously enabling both the targeted and untargeted metabolites characterization is established on a Q Exactive hybrid quadrupole-Orbitrap mass spectrometer, by integrating precursor ions list-triggered data-dependent MS2 acquisition (PIL/dd-MS2) of the targeted components and using the “If idle-pick others” (IIPO) function to induce untargeted metabolites fragmentation. A compounds-specific mass defect filter (MDF) algorithm is proposed as a method to generate the PIL. As a proof of concept, this strategy coupled with offline two-dimensional liquid chromatography (2D-LC) was applied to identify the multicomponents of a traditional Chinese medicine formula Erzhi Pill (EZP). A rigid MDF vehicle was elaborated by orthogonal screening of the integer mass and integer mass-dependent dynamic mass defects considering a variation of 20?ppm. The Full MS/dd-MS2 method enabling PIL and IIPO exhibited better performance than Full MS/dd-MS2 and Targeted SIM/dd-MS2 (selected ion monitoring) in respect of the sensitivity in identifying the targeted components and the ability to characterize more untargeted ones. As a consequence, 270 components were separated from EZP, and 146 thereof were selectively characterized. In conclusion, it is a practical, multifaced strategy facilitating the in-depth metabolites profiling and characterization of complex herbal and biological samples.Fukuma, T., Garcia, R., 2019. Atomic- and molecular-resolution mapping of solid–liquid interfaces by 3D atomic force microscopy. ACS Nano 12, 11785-11797. layers are ubiquitous in life and technology. Hence, interfacial aqueous layers have a central role in a wide range of phenomena from materials science to molecular and cell biology. A complete understanding of those processes requires, among other things, the development of very-sensitive and high-resolution instruments. Three-dimensional atomic force microscopy (3D-AFM) represents the latest and most successful attempt to generate atomically resolved three-dimensional images of solid–liquid interfaces. This review provides an overview of the 3D-AFM operating principles and its underlying physics. We illustrate and explain the capability of the instrument to resolve atomic defects on crystalline surfaces immersed in liquid. We also illustrate some of its applications to imaging the hydration structures on DNA or proteins. In the last section, we discuss some perspectives on emerging applications in materials science and molecular biology.Gambacorta, G., Menichetti, E., Trincianti, E., Torricelli, S., 2019. The Silurian climatic transition recorded in the epicontinental Baltica Sea. Palaeogeography, Palaeoclimatology, Palaeoecology 517, 16-29. transition from the Middle to Late Ordovician cold climate to the Silurian greenhouse phase was marked by major climatic and oceanographic changes. The vast epereic sea that during the early Paleozoic extended over the Baltic Plate for hundreds of kilometres recorded the dynamic processes that characterized this important climatic evolution. This shallow epicontinental sea experienced phases of hypoxic conditions for millions of years during the Silurian favouring the sedimentation of organic-rich deposits. A continuous core drilled in the Silurian fine-grained succession of the Baltic Basin was studied integrating sedimentological, palynological and geochemical data. The succession, deposited in a restricted environment in low-energy settings, recorded three long-term variations in bottom-water redox conditions. Our data highlight a direct control of long-term climatic changes on oceanic redox cycles. Phases of cool and dry climate with reduced runoff alternated with periods of warmer and humid conditions with higher runoff and fluvial discharge. During warmer and more humid climatic phases, the presence of a stable pycnocline hampered deep-water renewal efficiency, and together with increased nutrients led by enhanced weathering and runoff favoured the onset of anoxic bottom-water conditions. Cooler and drier intervals favoured instead a weaker and less stable pycnocline that, coupled with more oligotrophic conditions, drove the formation of oxic bottom-waters. The variation through time in water salinity and temperature influenced both the type of organic matter in the surface waters as well as its preservation along the water column. In fact, the extended residence time at the stable pycnocline during the anoxic phases led to the degradation of the organic matter and limited its accumulation at the sediment-water interface. The waning of the latest Ordovician cooling to the Silurian greenhouse climate was characterized by the progressive alternation of cool phases and warmer periods. The effect of this dynamic climatic instability on the redox state of the Baltica epicontinental sea protracted over millions of years up to the middle Silurian.Ganci, A.P., Vane, C.H., Abdallah, M.A.E., Moehring, T., Harrad, S., 2019. Legacy PBDEs and NBFRs in sediments of the tidal River Thames using liquid chromatography coupled to a high resolution accurate mass Orbitrap mass spectrometer. Science of The Total Environment 658, 1355-1366. sediment samples (n?=?45) were collected along a 110?km transect of the river Thames in October 2011, starting from Teddington Lock out through the industrial area of London to the southern North Sea. Several legacy and novel brominated flame retardants (NBFRs) were analysed, including 13 polybrominated diphenyl ethers (PBDEs) (congeners 17, 28, 47, 99, 100, 153, 154, 183, 196, 197, 206, 207 and 209), hexabromocyclododecane (HBCDDs), tetrabromobisphenol A (TBBPA), hexabromobenzene (HBB), 2,4,6-tribromophenol (TBP), 2-ethylhexyl 2,3,4,5-tetrabromobenzoate (EH-TBB or TBB), bis(2-ethylhexyl) tetrabromophthalate (BEH-TEBP or TBPH), 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE), decabromodiphenyl ethane (DBDPE), pentabromoethylbenzene (PBEB), anti/syn-dechlorane plus (a/s-DP), 2,2′,4,4′,5,5′-hexabromobiphenyl (BB153) and α-,β-1,2-dibromo-4-(1,2-dibromoethyl) cyclohexane (α-,β-DBE-DBCH or TBECH). A novel analysis method based on liquid chromatographic separation, followed by high resolution accurate mass detection using the Orbitrap platform was used for quantification. Results revealed that BDE-209 had the highest concentrations (<0.1 to 540?μg?kg?1 dw) and detection frequency, accounting for 95% of all PBDE congeners measured. Indicative evidence of debromination of the PentaBDE technical mixture was observed through elevated relative abundance of BDE-28 in sediment compared to the Penta-BDE formulation. NBFRs were detected at comparable levels to PBDEs (excluding BDE-209), which indicates increasing use of the former. Spatial trend analysis showed that samples from industrial areas had significantly higher concentrations of Σ12PBDEs, ΣHBCDDs, TBBPA, BEH-TEBP, BTBPE and TBP. Three locations showed high concentrations of HBCDDs with diastereomer patterns comparable to the technical mixture, which indicate recent input sources to the sediment.Gao, Y., Cai, X., Zhang, P., He, G., Gao, Q., Wan, J., 2018. Pore characteristics and evolution of Wufeng–Longmaxi Fms shale gas reservoirs in the basin-margin transition zone of SE Chongqing. Natural Gas Industry B 38, 15-25. present, researches on the pore evolution of shale reservoir and its evolution mechanism are still at such a groping stage that a consensus has not yet reached. Based on core analysis and thermal simulation experiments, the pore types, pore structures and pore-size change rules of shale gas reservoirs of Upper Ordovician Wufeng–Lower Silurian Longmaxi Fms in the southeastern (SE) Sichuan Basin and its basin-margin transition zone (hereinafter referred to as the basin-margin transition zone of SE Chongqing) were studied by means of argon ion polishing-scanning electron microscopy and atomic force microscopy. Then, the evolution characteristics of organic pores were discussed, and the influence of associated minerals on pore evolution was analyzed. Finally, a pore evolution model for the shale gas reservoirs in this area was established. And the following research results were obtained. First, three types of reservoir spaces are mainly developed in the high-quality shale reservoirs of Wufeng–Longmaxi Fms in this area, including fracture, inorganic pore and organic pore. And the organic pores provide the primary reservoir space of shale gas, which can be divided into four categories, i.e., amorphous kerogen pores, structured kerogen pores, asphaltene pores and paleontology fossil pores. Second, organic contracted fissures are related to the contraction of organic matters, first appearing on one side of the organic matters and then becomes wider and wider with the increase of temperatures. Third, organic pores are mostly the "spongy" pores distributed densely inside the organic matters. When Ro is in the range of 1.56–3.50%, macropores and mesopores are dominant. And when Ro exceeds 3.50%, macropores decrease while mesopores and micropores increase. Fourth, the types of organic matters and the content of associated minerals (e.g. clay minerals, siliceous particles and pyrite) play an important role in the development of pores. In conclusion, the pore evolution law of Wufeng–Longmaxi shale in the basin-margin transition zone of SE Chongqing is that with the increase of burial depth, inorganic porosity decreases significantly, organic porosity increases first and then decreases, and the total porosity shows a change trend of decreasing first, then increasing and finally decreasing continuously.Gao, Y., Wu, S., Cong, R., Xiao, J., Ma, F., 2019. Characterization of lignans in Schisandra chinensis oil with a single analysis process by UPLC-Q/TOF-MS. Chemistry and Physics of Lipids 218, 158-167. chinensis is a medicinal and edible plant that contains various bioactive compounds. Among these, lignans are the major functional compounds. Nevertheless, detailed information about lignans in Schisandra chinensis oil remains scarce. A powerful UPLC-Q/TOF-MS method was established for the rapid identification of the lignan constituents of Schisandra chinensis oils. The results showed that 21 lignans have been unambiguously identified, and four lignans have been tentatively identified in the Schisandra chinensis oils. In addition, semi-quantitative analysis indicated that the total lignan content in the Schisandra chinensis oils was distributed from 67.73?±?0.06 to 87.61?±?1.83?mg/g. Schisandrin and schisandrin B were the most abundant lignans in the Schisandra chinensis oils, their content ranging from 15.85?±?0.09 to 20.57?±?0.38?mg/g. Additionally, this study provided a systematic characterization of lignans in Schisandra chinensis oil and indicated that the oil might be used as lignan-related functional foods.García ?lvarez-Busto, A., Laca, A., Fernández González, A., 2019. Revealing the monastic kitchen: Chemical analysis of the soil inside the monastery of Cornellana (north-west Spain). Archaeometry 61, 145-160. residues deposited on the floor of the kitchen of the monastery of Cornellana (Asturias, Spain), while it was still in use in the 18th century, have been analysed using different techniques, including the Kjeldahl method, phenol?–?sulphuric acid assay, FT–IR, SEM–EDX and LOI. This has allowed us to determine the areas of concentration of proteins, carbohydrates, fatty acids, phosphorus and carbonates, and thus approach the interpretation of the layout of the different areas of activity related to the treatment and cooking of foodstuffs in the kitchen. In any case, and regardless of the fact that this is the first time that these techniques have been applied to study a monastic kitchen in the Iberian Peninsula, the aim of this research is to demonstrate their applicability to other case studies of this integrated set of analytical techniques, some of which are not used very often in the analysis of concentrations of residues and analysis of areas of activity on archaeological soils.Garlito, B., Portolés, T., Niessen, W.M.A., Navarro, J.C., Hontoria, F., Monroig, ?., Varó, I., Serrano, R., 2019. Identification of very long-chain (>C24) fatty acid methyl esters using gas chromatography coupled to quadrupole/time-of-flight mass spectrometry with atmospheric pressure chemical ionization source. Analytica Chimica Acta 1051, 103-109. chromatography coupled to a quadrupole time-of-flight mass analyzer (QTOF) with an atmospheric pressure chemical ionization (APCI) source has been tested to study the ionization and mass spectrometric behavior of long-chain and very long-chain polyunsaturated fatty acids (LC-PUFAs, C18–24; VLC-PUFAs, >C24). The protonated molecule ([M+H]+), measured at accurate mass, became the base peak of the spectrum for all the studied compounds and was promoted by the addition of water into the source. This fact overcame the existing difficulties for the identification of VLC-PUFAs when using an electron ionization source (EI). The extensive fragmentation of PUFAs in this source is the main drawback due to the fact that since reference standards are not commercially available, final identification relies on retention time estimation. The application of GC?APCI-QTOF to the screening of lipid extracts from the eyes of different fish species added confidence to the identification of several VLC-PUFAs. Further investigation of ion ratios allowed to predict the position of key double bonds enabling the classification of VLC-PUFAs as ω3 or ω6 compounds. VLC-PUFAs spectra found in biological samples were compared to those obtained from corresponding peaks found in heterologous expression experiments of fish's Elovl4.Gaudreau, A.M., Labrie, J., Goetz, C., Dufour, S., Jacques, M., 2018. Evaluation of MALDI-TOF mass spectrometry for the identification of bacteria growing as biofilms. Journal of Microbiological Methods 145, 79-81. evaluated MALDI-TOF mass spectrometry to identify bacteria from biofilms. We compared three sample preparation procedures on biofilms grown in vitro. The extended direct transfer method was able to identify 13 isolates out of 18 (72%) at the species level and 15 out of 18 (83%) at the genus level.Gay, A., Lopez, M., Potdevin, J.-L., Vidal, V., Varas, G., Favier, A., Tribovillard, N., 2019. 3D morphology and timing of the giant fossil pockmark of Beauvoisin, SE Basin of France. Journal of the Geological Society 176, 61. resolution of data acquired over modern seafloors does not allow imaging of the inner features of a fluid seep structure, particularly in the shallow subsurface. In the SE Basin of France (Dr?me), fossil cold seep structures comprising fossil-rich carbonate lenses were identified about 30?years ago within the Oxfordian (Late Jurassic) Terres Noires Formation. These structures were first interpreted as pseudo-bioherms related to hydrothermal activity, but comparison with active seep sites on modern margins, together with isotopic analyses, led to a reinterpretation involving cold fluids instead. To date, all seep sites have generally been studied individually without considering any link to neighbouring or more distant sites. Based on 23 high-resolution stratigraphic logs within the structure coupled to mosaicked aerial photographs from a drone survey, 19 fluid seep events were correlated in the area, including two new sites exposed as a result of weathering. We have shown that each identified sub-site is composed of subvertically stacked fossil-rich carbonate lenses interbedded with marls, which developed in smooth, 4–6?m deep depressions beneath the local seabed. The nodules present within the depressions are of primary importance as they mark the area of active seeping. This general organization is very similar to the modern Regab giant pockmark in the Lower Congo Basin where only a few sub-sites are active at the same time. A spatio-temporal 3D reconstruction of the position of these sub-sites shows that the carbonate lenses are organized into clusters comprising up to seven sub-sites grouped together in the same stratigraphic interval and the same geographical zone. A sandbox experiment where gas is injected at constant flow rate at the base of a box filled with a matrix of water-saturated grains displays a pattern consisting of disturbed sediments inside a parabolic-shaped area. This parabolic shape was also identified on a seismic profile across the Regab giant pockmark, suggesting that the processes are similar for the Beauvoisin and Regab seep areas. The laboratory experiments also show that the seeping conduit is stable during a given period of time and suddenly shifts laterally. This is mainly as a result of the collapse of the conduit, the lateral migration and the reopening at a new position. The general log obtained in the Beauvoisin seep area suggests a similar pattern with periods of seeping alternating with periods of quiescence, each of which is c. 200?kyr. Even if a pockmark seems to have been inactive for a long period of time, this could be due to the lateral shift of the feeder conduit, meaning that the sub-seafloor is still charged with gas. This is of primary importance for risk assessment, hydrocarbon exploration and general understanding of geobiology at seafloor seeps.Ge, H., Zhang, Z., 2019. Origin and accumulation of Paleogene oil in Qingdong sag, Jiyang depression, eastern China. Journal of Petroleum Science and Engineering 176, 150-160. study reports on the geochemical examination of 18 core samples and 22 crude oil samples from the Qingdong and Dongying sags. Both conventional and heavy oils coexist in the Qingdong Sag, with the heavy oil resulting from biodegradation. Based on the oil-source rock correlation, the conventional oil mainly originates from the Es3l source rock in the central and northern sub-sags, with the biodegraded oil in the western slope having been derived from the Es4u source rock in the central and northern sub-sags. The biodegraded oil in the transition belt is mostly derived from the Dongying Sag (Es4u). The biodegraded oil in the Qingdong-5 area originated from the Es4u member near the Qingdong-5 area in the southern sub-sags. Two stages of oil charging were identified in the Qingdong Sag based on the basin modelling. The first stage occurred during the deposition of the Dongying Formation (Ed) in the Paleogene, and the second stage occurred during the deposition of the Guantao Formation from the Neogene to Quaternary (Ng-Q). The conventional oil in the central and northern parts of the study area mainly accumulated during the second stage and migrated both laterally through the sand-bodies and vertically along the steep faults. The heavy oil in the transition belt mostly accumulated during the second stage, migrating a long distance along the en-echelon step-fault zone, and suffered severe biodegradation. Both stages of oil charging were responsible for the heavy oil in the Qingdong-5 area and the western slope. The former migrated a short distance before being trapped, while the latter moved long distance along the fault strike. The oil charged during the first stage was subject to alteration, eventually being mixed with oil from the second charging event.Ge, M., Ren, S., Guo, T., Zhou, Z., Wang, S., Bao, S., 2018. Characterizing the micropores in lacustrine shales of the Late Cretaceous Qingshankou Formation of southern Songliao Basin, NE China. Acta Geologica Sinica - English Edition 92, 2267-2279. of shale are significant to the gas content and production potential of shale, which has been verified in the research of marine shale gas; while, few studies have been conducted on lacustrine shales. This study collected 42 samples from three wells in the Late Cretaceous Qingshankou Formation of the southern Songliao Basin, NE China, and investigated these samples by the focused ion beam‐scanning electron microscope (FIB–SEM) and nitrogen adsorption analysis techniques. Four types of micropores were identified in the samples, i.e., intergranular pore, intracellular pore, organic matter pore and microfracture. The pore structure type is characterized by open slit pores and “ink type” pores which are mainly 1.5–5 nm in diameter with mesopores as the main pores. The mesopores account for 74.01% of the pore volume and 54.68% of the pore surface area. Compared with the lacustrine shales from the Triassic Yanchang Formation in the Ordos Basin and Xujiahe Formation in the Sichuan Basin, the intergranular clay mineral interlayer pores are considered to be the main reservoir space for shale gas storage in the study area, followed by intraparticle pores, organic matter pores and microfractures. Maturity and micropore are the key controlling factors which affect the shale gas content of the Qingshankou Formation in southern Songliao Basin.Gebbie, G., Huybers, P., 2019. The Little Ice Age and 20th-century deep Pacific cooling. Science 363, 70-74.: Proxy records show that before the onset of modern anthropogenic warming, globally coherent cooling occurred from the Medieval Warm Period to the Little Ice Age. The long memory of the ocean suggests that these historical surface anomalies are associated with ongoing deep-ocean temperature adjustments. Combining an ocean model with modern and paleoceanographic data leads to a prediction that the deep Pacific is still adjusting to the cooling going into the Little Ice Age, whereas temperature trends in the surface ocean and deep Atlantic reflect modern warming. This prediction is corroborated by temperature changes identified between the HMS Challenger expedition of the 1870s and modern hydrography. The implied heat loss in the deep ocean since 1750 CE offsets one-fourth of the global heat gain in the upper ocean.Editor's Summary, Deep Pacific cooling: Earth's climate cooled considerably across the transition from the Medieval Warm Period to the Little Ice Age about 700 years ago. Theoretically, owing to how the ocean circulates, this cooling should be recorded in Pacific deep-ocean temperatures, where water that was on the surface then is found today. Gebbie and Huybers used an ocean circulation model and observations from both the end of the 19th century and the end of the 20th century to detect and quantify this trend. The ongoing deep Pacific is cooling, which revises Earth's overall heat budget since 1750 downward by 35%.Gerschlauer, F., Saiz, G., Schellenberger Costa, D., Kleyer, M., Dannenmann, M., Kiese, R., 2019. Stable carbon and nitrogen isotopic composition of leaves, litter, and soils of various ecosystems along an elevational and land-use gradient at Mount Kilimanjaro, Tanzania. Biogeosciences 16, 409-424. in the stable isotopic composition of carbon (δ13C) and nitrogen (δ15N) of fresh leaves, litter, and topsoils were used to characterize soil organic matter dynamics of 12 tropical ecosystems in the Mount Kilimanjaro region, Tanzania. We studied a total of 60 sites distributed along five individual elevational transects (860–4550?m?a.s.l.), which define a strong climatic and land-use gradient encompassing semi-natural and managed ecosystems. The combined effects of contrasting environmental conditions, vegetation, soil, and management practices had a strong impact on the δ13C and δ15N values observed in the different ecosystems. The relative abundance of C3 and C4 plants greatly determined the δ13C of a given ecosystem. In contrast, δ15N values were largely controlled by land-use intensification and climatic conditions.The large δ13C enrichment factors (δ13Clitter???δ13Csoil) and low soil C∕N ratios observed in managed and disturbed systems agree well with the notion of altered SOM dynamics. Besides the systematic removal of the plant biomass characteristic of agricultural systems, annual litterfall patterns may also explain the comparatively lower contents of C and N observed in the topsoils of these intensively managed sites. Both δ15N values and calculated δ15N-based enrichment factors (δ15Nlitter???δ15Nsoil) suggest the tightest nitrogen cycling at high-elevation (>?3000?m?a.s.l.) ecosystems and more open nitrogen cycling both in grass-dominated and intensively managed cropping systems. However, claims about the nature of the N cycle (i.e. open or closed) should not be made solely on the basis of soil δ15N as other processes that barely discriminate against 15N (i.e. soil nitrate leaching) have been shown to be quite significant in Mount Kilimanjaro's forest ecosystems. The negative correlation of δ15N values with soil nitrogen content and the positive correlation with mean annual temperature suggest reduced mineralization rates and thus limited nitrogen availability, at least in high-elevation ecosystems. By contrast, intensively managed systems are characterized by lower soil nitrogen contents and warmer conditions, leading together with nitrogen fertilizer inputs to lower nitrogen retention and thus significantly higher soil δ15N values. A simple function driven by soil nitrogen content and mean annual temperature explained 68?% of the variability in soil δ15N values across all sites. Based on our results, we suggest that in addition to land-use intensification, increasing temperatures in a changing climate may promote soil carbon and nitrogen losses, thus altering the otherwise stable soil organic matter dynamics of Mount Kilimanjaro's forest ecosystems.Gharasoo, M., Babaei, M., Haeckel, M., 2019. Simulating the chemical kinetics of CO2-methane exchange in hydrate. Journal of Natural Gas Science and Engineering 62, 330-339. dioxide exchange with methane in the clathrate structure has been shown beneficial in laboratory experiments and has been suggested as a field-scale technique for production of natural gas from gas-hydrate bearing sediments. Furthermore, the method is environmentally attractive due to the formation of CO2-hydrate in the sediments, leading to the geosequestration of carbon dioxide. However, the knowledge is still limited on the impact of small-scale heterogeneities on hydrate dissociation kinetics. In the present study, we developed a model for simulating laboratory experiments of carbon dioxide injection into a pressure vessel containing a mixture of gas hydrate and quartz sand. Four experiments at different temperature and pressure conditions were modeled. The model assumes that the contents are ideally mixed and aims to estimate the effective dissociation rate of gas hydrate by matching the model results with the experimental observations. Simulation results indicate that with a marginal offset the model was able to simulate different hydrate dissociation experiments, in particular, those that are performed at high pressures and low temperatures. At low pressures and high temperatures large discrepancies were noticed between the model results and the experimental observations. The mismatches were attributed to the development of extremely heterogeneous flow patterns at pore-scale, where field-scale models usually assume the characteristics to be uniform. Through this modeling study we estimated the irreversible dissociation rate of methane- and CO2-hydrate as 0.02 and 0.03?mol?m?3s?1, respectively.Ghezal, S., Ciesielski, E., Girard, B., Creuzieux, A., Gosnell, P., Mathe, C., Vieillescazes, C., Roure, R., 2019. Embalmed heads of the Celtic Iron Age in the south of France. Journal of Archaeological Science 101, 181-188. texts described that one of the most impressive ritual practices of the Celts during the Iron Age was to remove the heads of enemies killed in battle and to embalm them for display in front of the victors dwellings. An archaeological settlement excavation site in Le Cailar, in southern France, has revealed a considerable number of examples of this practice. It was documented by Classical authors and later by the archaeological recording of iconographic representations and skeletal remains of human heads. Weapons were also exhibited alongside the severed heads. Here we report the results of chemical investigations for the characterization of the biomarkers of embalming that are likely to be present in eleven fragments of these human cranial remains. These results may lead to answers to some of the archaeometric questions related to the subject of embalming in 3rd century BC Transalpine Gaul, thus advancing the knowledge of these ritual practices, documented by Greek Classical authors as part of the wider research into the proto-historic societies of the Mediterranean coastal region.Ghizelini, A.M., Martins, K.G., Gie?elmann, U.C., Santoro, E., Pasqualette, L., Mendon?a-Hagler, L.C.S., Rosado, A.S., Macrae, A., 2019. Fungal communities in oil contaminated mangrove sediments – Who is in the mud? Marine Pollution Bulletin 139, 181-188. are ecosystems located in tropical and subtropical regions of the world and are vital for coastal protection. Their unique characteristics make them hotspots for carbon cycling and biological diversity. Studies on isolated filamentous fungi and environmental and anthropogenic factors that influence sediments offer new understandings on how to preserve mangroves. Here we report on the filamentous fungi isolated from four mangroves. We correlated fungal community composition with sediment texture, polycyclic aromatic hydrocarbons concentration (oil pollution), pH, salinity, organic matter, total and thermotolerant coliforms (sewage pollution). In total we identified 34 genera and 97 species. The most polluted sites had highest species richness whereas the best preserved site showed the lowest species richness. Oil spill and sewage pollution were identified as the drivers of fungal community composition in the most polluted sites. We found very distinct fungal communities with no >5 species shared between any two mangrove sites.Ghloum, E.F., Rashed, A.M., Safa, M.A., Sablit, R.C., Al-Jouhar, S.M., 2019. Mitigation of asphaltenes precipitation phenomenon via chemical inhibitors. Journal of Petroleum Science and Engineering 175, 495-507. main aim of this study is to mitigate asphaltenes precipitation phenomenon using chemical inhibitors under reservoir conditions. Different conventional screening test methods such as UV-Vis and solids detection system (SDS) equipped with a low-intensity near infrared (NIR) light and a high-pressure microscope (HPM) were used to assess the effectiveness of asphaltenes inhibitors on a stock tank oil (STO) and downhole samples (DHS). These tests have been employed as part of a rigorous investigation to understand (evaluate) the performance of chemical inhibitors in mitigating asphaltene precipitation and deposition. The extracted asphaltenes were characterized by higher aromaticity due to relatively low hydrogen/carbon molar ratios, hence, the higher tendency of asphaltenes aggregation and subsequent precipitation upon changes in thermodynamic factors. Moreover, the evaluation tests of the commercial asphaltenes inhibitors showed efficient asphaltenes dispersion performance when tested by using different conventional methods. Finally, the high-pressure microscope tests conducted on the DHS at reservoir temperature showed that the most efficient inhibitors reduced the aggregated asphaltenes average particles size by 58%. This is attributed to the presence of the high aromatic content, and polar acidic and/or alcoholic functionalities in the molecular structures of those inhibitors, which is vital for the dispersion of the asphaltenes and the prevention of the formation of large asphaltenes aggregates through π-π interactions and van der Waals forces.Ghosh, A., Foster, A.R., Johnson, J.C., Vilorio, C.R., Tolley, L.T., Iverson, B.D., Hawkins, A.R., Tolley, H.D., Lee, M.L., 2019. Stainless-steel column for robust, high-temperature microchip gas chromatography. Analytical Chemistry 90, 792-796. paper reports the first results of a robust, high-performance, stainless-steel microchip gas-chromatography (GC) column that is capable of analyzing complex real-world mixtures as well as operating at very high temperatures. Using a serpentine design, a 10 m column with an approximately semicircular cross-section with a 52 μm hydraulic diameter (Dh) was produced in a 17 × 6.3 × 0.1 cm rectangular steel chip. The channels were produced using a multilayer-chemical-etch and diffusion-bonding process, and metal nuts were brazed onto the inlet and outlet ports allowing for column interfacing with ferrules and fused silica capillary tubing. After deactivating the metal surface, channels were statically coated with a ≈0.1 μm layer of 5% phenyl–1% vinyl–methylpolysiloxane (SE-54) stationary phase and cross-linked with dicumyl peroxide. By using n-tridecane (n-C13) as a test analyte with a retention factor (k) of 5, a total of 44?500 plates (≈4500 plates per meter) was obtained isothermally at 120 °C. The column was thermally stable to at least 350 °C, and rapid temperature programming (35 °C/min) was demonstrated for the boiling-point range from n-C5 to n-C44 (ASTM D2887 simulated-distillation standard). The column was also tested for separation of two complex mixtures: gasoline headspace and kerosene. These initial experiments demonstrate that the planar stainless-steel column with proper interfacing can be a viable alternative platform for portable, robust microchip GC that is capable of high-temperature operation for low-volatility-compound analysis.Giani, D., Baini, M., Galli, M., Casini, S., Fossi, M.C., 2019. Microplastics occurrence in edible fish species (Mullus barbatus and Merluccius merluccius) collected in three different geographical sub-areas of the Mediterranean Sea. Marine Pollution Bulletin 140, 129-137. gastrointestinal tracts of 229 demersal fish belonging to two species (Mullus barbatus, Merluccius merluccius) were examined for microplastic ingestion. Samples were collected in 3 different FAO Geographical Sub-Areas (GSA-9, GSA-17, GSA-19) of the Mediterranean Sea. Ingested microplastics were characterized using a stereo-microscope: observed, photographed, measured and categorized according to size class, shape and colour. Plastic fragments (ranging from 0.10 to 6.6?mm) were detected in 23.3% of the total investigated fish; a total of 65 plastic particles (66% constituted by fibers) were recorded. The percentage of plastic ingestion shows high variability between the two species and among the different sampling area. The highest frequency (48%) was found in European hake from GSA-19. These preliminary results represent a baseline for the implementation of the Marine Strategy Framework Directive descriptor 10 in Italy as well as an important step for detecting microplastics in bioindicator species from different GSAs.Gibbons, A., 2019. A room with a view—for three kinds of humans. Science 363, 438. its light-filled main gallery and sweeping views of the Altai Mountains of southern Russia, Denisova Cave was a Stone Age version of a Manhattan penthouse. Overlooking the Anui River, where herds of animals came to drink, it offered an unparalleled vantage for spotting game and other humans, as well as refuge from Siberian storms. Generations of Neanderthals, their Denisovan cousins, and modern humans enjoyed the view.But when did each group reside there? The timing could yield clues to how these diverse humans interacted and shed new light on the most enigmatic of the three, the Denisovans, who are known only from DNA and scrappy fossils from this cave. Denisova's human fossils and artifacts have been notoriously difficult to date (Science, 26 August 2011, p. 1084) because of the complex layering of sediments in its three chambers. Now, two teams have combined state-of-the-art dating methods to create a timeline of the cave's occupants.For the Denisovans, the results—reported in Nature this week—paint a portrait of endurance. They first moved in 287,000 years ago, more than 100,000 years earlier than had been thought, and then occupied the cave off and on through shifting climates until 55,000 years ago, a period when Neanderthals also came and went. “The general picture is now clear,” says archaeologist Robin Dennell of the University of Sheffield in the United Kingdom, who was not a member of the teams.Ever since DNA extracted from a girl's tiny pinkie bone found in the cave revealed that she belonged to a formerly unknown type of human, researchers have been trying to nail down when the Denisovans lived. In 2015, several samples of cut-marked animal bones and charcoal found near the pinkie bone yielded radiocarbon dates of at least 50,000 years, at the oldest limit of the method. But that was a minimum age because bone fragments, teeth, and DNA from four other Denisovans and from a young woman whose DNA shows she had a Neanderthal mother and a Denisovan father have also been found in the cave, some in deeper, older layers (Science, 24 August 2018, p. 737 <;). One tooth might have been as old as 170,000 years (Science, 18 September 2015, p. 1270 <;).Those older dates had wide margins of error. So, Russian Academy of Sciences archaeologists who have been excavating at Denisova for 40 years invited geochronologists Zenobia Jacobs and Richard Roberts of the University of Wollongong in Australia to try state-of-the-art optical dating methods. Optical dating reveals when single grains of quartz or potassium feldspar in a sample of sediment were last exposed to sunlight and, thus, when the sediment was deposited. By measuring 280,000 individual grains of these minerals in more than 100 samples collected near stone tools or fossils, the Wollongong team calculated the average age of every layer of the cave's deposits.The team checked its dates for the most recent layers against radiocarbon dates that geochronologists Tom Higham and Katerina Douka at the University of Oxford in the United Kingdom determined from 50 new cut-marked bone and charcoal samples. The Oxford team also developed a new statistical model that merges data from several dating methods, as well as from genetic sequencing, which can reveal the relative ages of fossils. By evaluating all the data and their range of errors, the model determines which dates are most reliable. “There's a huge value in using multiple techniques,” says Ed Rhodes of the University of Sheffield, who was not involved in the work. The resulting dates, he adds, are “fully convincing.”The oldest stone tools in the cave date back to at least 287,000 years, according to the optical methods. These so-called Middle Paleolithic tools look subtly different from those associated with Neanderthals in other caves in Siberia, suggesting they are the first artifacts ever linked to the Denisovans. Direct evidence of Denisovans—so-called environmental DNA found in the sediments—also appears a bit before DNA from Neanderthals, who occupied the cave on and off from 193,000 to 97,000 years ago (Science, 12 May 2017, p. 605 <;).The Denisovans were “evidently a hardy bunch,” Jacobs says. They apparently persisted at the site through multiple episodes of cold Siberian climate, based on analysis of fossil pollen. In contrast, when the Neanderthals showed up, the pollen shows that the forest around the cave had hornbeam, oak, and Eurasian linden trees, which thrive in a relatively warm and humid climate.The dates also suggest a new puzzle: Who made so-called Initial Upper Paleolithic artifacts, such as ornaments of bone, animal teeth, mammoth ivory, and ostrich eggshell, that date to between 43,000 to 49,000 years at the site? Higham's Russian collaborators propose they were made by Denisovans, like the tools from older layers. No modern human fossils have been found in the cave, they note. But others say the artifacts resemble the handiwork of modern humans in Eurasia, suggesting the newcomers arrived just after the Denisovans vanished—or even hastened the disappearance of this lost group.“My money would be on early modern humans, who can be mapped elsewhere at this date, for example at Ust'-Ishim in Siberia,” says paleoanthropologist Chris Stringer of the Natural History Museum in London, not a member of the team. “Only more discoveries and more research can resolve that question.”Gilevska, T., Passeport, E., Shayan, M., Seger, E., Lutz, E.J., West, K.A., Morgan, S.A., Mack, E.E., Sherwood Lollar, B., 2019. Determination of in situ biodegradation rates via a novel high resolution isotopic approach in contaminated sediments. Water Research 149, 632-639. key challenge in conceptual models for contaminated sites is identification of the multiplicity of processes controlling contaminant concentrations and distribution as well as quantification of the rates at which such processes occur. Conventional protocol for calculating biodegradation rates can lead to overestimation by attributing concentration decreases to degradation alone. This study reports a novel approach of assessing in situ biodegradation rates of monochlorobenzene (MCB) and benzene in contaminated sediments. Passive diffusion samplers allowing cm-scale vertical resolution across the sediment-water interface were coupled with measurements of concentrations and stable carbon isotope signatures to identify zones of active biodegradation of both compounds. Large isotopic enrichment trends in 13C were observed for MCB (1.9–5.7‰), with correlated isotopic depletion in 13C for benzene (1.0–7.0‰), consistent with expected isotope signatures for substrate and daughter product produced by in situ biodegradation. Importantly in the uppermost sediments, benzene too showed a pronounced 13C enrichment trend of up to 2.2‰, providing definitive evidence for simultaneous degradation as well as production of benzene. The hydrogeological concept of representative elementary volume was applied to CSIA data for the first time and identified a critical zone of 10–15?cm with highest biodegradation potential in the sediments. Using both stable isotope-derived rate calculations and numerical modeling, we show that MCB degraded at a slower rate (0.1–1.4 yr?1 and 0.2–3.2 yr?1, respectively) than benzene (3.3–84.0 yr?1) within the most biologically active zone of the sediment, contributing to detoxification.Goddéris, Y., Donnadieu, Y., 2019. A sink- or a source-driven carbon cycle at the geological timescale? Relative importance of palaeogeography versus solid Earth degassing rate in the Phanerozoic climatic evolution. Geological Magazine 156, 355-365. Phanerozoic evolution of the atmospheric CO2 level is controlled by the fluxes entering or leaving the exospheric system. In this contribution, we focus on the role played by the palaeogeographic configuration on the efficiency of the CO2 sink by continental silicate weathering, and on the impact of the magmatic degassing of CO2 . We use the spatially resolved numerical model GEOCLIM to compute the response of the silicate weathering and atmospheric CO2 to continental drift for 22 time slices of the Phanerozoic. Regarding the CO2 released by the magmatic activity, we reconstruct several Phanerozoic histories of this flux, based on published indices. Again using the GEOCLIM model, we calculate the CO2 evolution for each degassing scenario. We show that the palaeogeographic setting is a main driver of the climate from 540 Ma to about the beginning of the Jurassic, with the noticeable exception of the Late Palaeozoic ice age. Regarding the role of the magmatic degassing, the various reconstructions do not converge towards a single signal, and thus introduce large uncertainties in the calculated CO2 level over time. Nevertheless, the continental dispersion, which prevails since the Jurassic, promotes CO2 consumption by weathering and forces atmospheric CO2 to stay low. Warm climates of the ‘middle’ Cretaceous and early Cenozoic require enhanced CO2 degassing by magmatic activity.Gong, D., Song, Y., Wei, Y., Liu, C., Wu, Y., Zhang, L., Cui, H., 2019. Geochemical characteristics of Carboniferous coaly source rocks and natural gases in the Southeastern Junggar Basin, NW China: Implications for new hydrocarbon explorations. International Journal of Coal Geology 202, 171-189. Upper Carboniferous coaly source rocks are verified to be developed in the Southeastern Junggar Basin, which is lithologically composed of carbonaceous mudstones and mudstones. According to the geochemical (total organic carbon, Rock–Eval, and biomarker fingerprints) and organic petrology analyses, the Carboniferous source rocks are primarily gas-prone characterized by kerogen type III, and were deposited in an oxidized–sub-oxidized brackish environment significantly contributed by terrigenous higher plants. Carbonaceous mudstones are generally more oil-prone in comparison with the mudstones. The measured vitrinite reflectance, Tmax, and sterane isomers indicate that the source rocks are at immature–early gas generation stage, and have not entered the “peak gas generation stage”. Natural gases are coal-type gases derived from the Carboniferous source rock. The maturities of them are highly inconsistent with those of source rock samples. Based on 2-D basin modeling, natural gases were generated from the highly mature coaly source rocks in the Fukang Depression and migrated upward to the uplift via the P–C regional inconformity.Gould, J., Kienast, M., Dowd, M., Schefu?, E., 2019. An open-ocean assessment of alkenone δD as a paleo-salinity proxy. Geochimica et Cosmochimica Acta 246, 478-497. surface salinity (SSS) is the least constrained major variable of the past (paleo) ocean but is fundamental in controlling the density of seawater and thus large-scale ocean circulation. The hydrogen isotopic composition (δD) of non-exchangeable hydrogen of algal lipids, specifically alkenones, has been proposed as a promising new proxy for paleo SSS. The δD of surface seawater is correlated with SSS, and laboratory culture studies have shown the δD of algal growth water to be reflected in the δD of alkenones. However, a large-scale field study testing the validity of this proxy is still lacking. Here we present the δD of open-ocean Atlantic and Pacific surface waters and coincident δD of alkenones sampled by underway filtration. Two transects of approximately 100° latitude in the Atlantic Ocean and more than 50° latitude in the western Pacific sample much of the range of open ocean salinities and seawater δD, and thus allow probing the relationship between δD of seawater and alkenones. Overall, the open ocean δD alkenone data correlate significantly with SSS, and also agree remarkably well with δD water vs δD alkenone regressions developed from culture studies. Subtle deviations from these regressions are discussed in the context of physiological factors as recorded in the carbon isotopic composition of alkenones. In a best-case scenario, the data presented here suggest that SSS variations as low as 1.2 can be reconstructed from alkenone δD.Grewal, D.S., Dasgupta, R., Sun, C., Tsuno, K., Costin, G., 2019. Delivery of carbon, nitrogen, and sulfur to the silicate Earth by a giant impact. Science Advances 5, Article eaau3669.’s status as the only life-sustaining planet is a result of the timing and delivery mechanism of carbon (C), nitrogen (N), sulfur (S), and hydrogen (H). On the basis of their isotopic signatures, terrestrial volatiles are thought to have derived from carbonaceous chondrites, while the isotopic compositions of nonvolatile major and trace elements suggest that enstatite chondrite–like materials are the primary building blocks of Earth. However, the C/N ratio of the bulk silicate Earth (BSE) is superchondritic, which rules out volatile delivery by a chondritic late veneer. In addition, if delivered during the main phase of Earth’s accretion, then, owing to the greater siderophile (metal loving) nature of C relative to N, core formation should have left behind a subchondritic C/N ratio in the BSE. Here, we present high pressure-temperature experiments to constrain the fate of mixed C-N-S volatiles during core-mantle segregation in the planetary embryo magma oceans and show that C becomes much less siderophile in N-bearing and S-rich alloys, while the siderophile character of N remains largely unaffected in the presence of S. Using the new data and inverse Monte Carlo simulations, we show that the impact of a Mars-sized planet, having minimal contributions from carbonaceous chondrite-like material and coinciding with the Moon-forming event, can be the source of major volatiles in the BSE.Gu, Y., Ding, W., Yin, M., Jiao, B., Shi, S., Li, A., Xiao, Z., Wang, Z., 2018. Nanoscale pore characteristics and fractal characteristics of organic-rich shale: An example from the lower Cambrian Niutitang Formation in the Fenggang block in northern Guizhou Province, South China. Energy Exploration & Exploitation 37, 273-295. marine shale in South China has great potential for gas generation, and the pore structure has a considerable influence on the enrichment of shale gas. The nanoscale pore characteristics and fractal characteristics of the Niutitang shales in the Fenggang block were studied by means of methane adsorption and low-pressure nitrogen adsorption experiments, porosity and permeability tests, X-ray diffraction analyses, organic geochemical analyses, and field emission scanning electron microscopy. The fractal geometry of the pore structure was assessed, and the factors influencing the pore structure were determined. We used a fractal Frenkel?Halsey?Hill-based method to obtain the fractal dimensions D1 and D2 by nitrogen adsorption at relative pressures of 0?0.5 and 0.5?1, respectively. The relationships between the shale pore structure parameters and the fractal dimensions, the mineral composition, the total organic carbon content, and the pore structure parameters of shale are discussed. In addition, the significance of D1 and D2 and the implications of the fractal dimension for the adsorption capacity of shale are investigated. The results show that the two fractal dimensions are positively correlated with total organic carbon content and specific surface area, negatively correlated with quartz content and average pore diameter, but have a weak relationship with clay mineral content and total pore volume. The Niutitang shale samples are dominated by mesopores, and the pore structure is complicated. The results presented here indicate that fractal analyses represent an effective method of characterizing the complexity of pore structure.Guo, Y., Deng, W., Wei, G., 2019. Kinetic effects during the experimental transition of aragonite to calcite in aqueous solution: Insights from clumped and oxygen isotope signatures. Geochimica et Cosmochimica Acta 248, 210-230. reconstructions based on the clumped isotopes (Δ47) and traditional isotope (δ13C or δ18O) techniques are often problematic for carbonates that have undergone diagenetic alteration. One of the most common types of diagenesis is the transition between polymorphs, such as the replacement of aragonite by calcite. The isotope fractionation during such transitions in aqueous solutions remains unclear. We conducted a series of aragonite-to-calcite transition experiments in aqueous solutions of varying salinity and experiment durations at 25?°C and 90?°C to examine the variations of δ13C, δ18O, and Δ47 values for carbonates at varying degrees of the transition. The results confirm the retarding effect of Mg2+ and the catalytic effect of Na+ and Ca2+ on the transition, which are consistent with previous findings. Compared with the results from the transitions at 25?°C, the 90?°C experiments show a greater transition to calcite and a more depleted oxygen isotope composition. However, both clumped and carbon isotope values show no significant variation in the various experiments, suggesting that they are unaffected by mineralogical transition. Based on published equilibrium calibrations for δ18O and Δ47, the results demonstrate that kinetic effects in isotope systems are controlled primarily by the rate of polymorph transition, but there is a significant kinetic difference between the clumped isotope bond (13C—18O) reordering and the 18O exchange within the dissolved inorganic carbon pool. This kinetic difference results in partial equilibration in δ18O with no significant reordering in Δ47 toward their equilibriums, which can be accounted for by the difference of equilibration rates between the oxygen isotopes bound to 12C and those bound to 13C. This study provides a clear observation of the response of isotope systems to carbonate polymorph transitions and sheds light on their reliability as paleoenvironmental proxies.Gupta, I., Rai, C., Sondergeld, C., 2019. Study impact of sample treatment and in situ fluids on shale wettability measurement using NMR. Journal of Petroleum Science and Engineering 176, 352-361. Magnetic Resonance (NMR) is a good alternative to conventional Amott-Harvey imbibition test or US Bureau of Mines (USBM) test, to measure wettability in shales. The conventional methods do not work primarily because of the long time it takes to flow through the nano pores in the shales. Contact angle measurements typically used in shales do not account for pore connectivity. Hence, NMR is becoming a standard reliable method to measure wettability in shales. This study focuses on two aspects of wettability measurement in shales. First, Looyestijn and Hofman (2006) proposed an equation to calculate wettability using NMR data based on their experiments on carbonate rocks. Sulucarnain et al. (2012) applied this method to shales. In their method, the residual fluids in the plugs are neglected because it is difficult to ascertain what proportion of residual fluids is hydrocarbon and what proportion is water. However, in liquid-rich shales like Eagle Ford, there could be significant amount of residual fluids which must be accounted in the wettability calculation. This study integrates Source Rock Analysis (SRA), NMR and helium porosity data to determine the nature of the residual fluids and account for them while doing wettability calculations. Thus, an improved equation for wettability is proposed by modifying the original equation. Second, in this study, wettability measurements on preserved, dried and cleaned sample states were carried out. The comparison of the three states suggest that drying and cleaning the samples, changes the original wettability of the system and make the rocks appear more oil wet. The effects of drying are more pronounced than cleaning. The above argument is supported both by SRA data and Scanning Electron Microscope (SEM) images. The SRA data shows an increase in S1 and a corresponding decrease in S2 peak which suggests that heating the sample at 100?°C may crack the heavy hydrocarbons in the sample. The SEM image analysis also show the possible movement and resolidification of bitumen and other heavy hydrocarbons. These mobile fractions are believed to flow into the water-wet pores and turn them oil-wet.Gusa, A.V., Vidic, R.D., 2019. Development of functionalized proppant for the control of NORM in Marcellus Shale produced water. Environmental Science & Technology 53, 373-382. of the major environmental concerns with the recovery of unconventional gas resource from Marcellus Shale is the presence of naturally occurring radioactive material (NORM) in produced water. Ra-226 is the major component of NORM with a half-life of 1600 years that is present at concentrations as high as several thousand pCi/L. Most of the studies on NORM management are focused on above-ground scenarios. The main focus of this study was on functionalizing the proppant (i.e., quartz sand) that is used in hydraulic fracturing to prevent the closure of induced fractures formed during this process and allow release of natural gas so that it can also sequester NORM from the produced water before it reaches the surface. Five different sulfates and carbonates were tested for their ability to capture Ra-226 from aqueous solution and celestite (SrSO4) was identified as the best choice because of its affinity for Ra-226 sequestration even in the presence of very high total dissolved solids that are characteristic of Marcellus Shale produced water. Among possible ways of coating the proppant with celestite, precipitating celestite directly on the sand surface was found to be the best option as it provided a uniform distribution of celestite and high uptake of Ra-226. Although quartz sand can adsorb some radium from the solution due to electrostatic interactions, adding a small amount of celestite on the sand surface (20–30 mg/g) increased radium removal from the solution containing 5000 pCi/L of Ra-226 to more than 80% in dilute solution and to more than 50% in high-salinity solution even in the presence of very high concentrations of competing divalent cations. The results of this study indicate the potential of coated proppant to sequester NORM in the subsurface and prevent adverse environmental impacts when radiogenic produced water is brought to the surface.Gustafsson, J.P., 2019. Vanadium geochemistry in the biogeosphere –speciation, solid-solution interactions, and ecotoxicity. Applied Geochemistry 102, 1-25. is a metal that receives increasing attention due to its possible toxicity and its increased use in society, i.e. in high-grade steel and in vanadium redox-flow batteries. Already today, the global biogeochemical cycle of vanadium is heavily impacted by human activities, and these impacts will probably increase. The total V concentration in the upper part of the Earth's crust, and in soils, is near 100?mg?V kg?1. Usually, the dissolved V concentration is low. In seawater the mean dissolved V concentration is 1.8?μg?L?1, and in freshwaters the concentration is commonly below 1?μg?L?1 although in areas with volcanic and sedimentary rocks it may be much higher, i.e. at the slopes of Mt. Etna, Italy, concentrations of up to 180?μg?V L?1 have been recorded.Vanadium is a redox-sensitive element, which occurs in three oxidation states (+III, +IV and +V) in the environment. Whereas vanadium(V) usually occurs as the oxyanion vanadate(V) under most environmental conditions, vanadyl(IV) is an oxocation that is stable at low pH and/or mildly reducing conditions, particularly when the organic matter concentration is high. Vanadium(III), which is the least studied form of vanadium, occurs under strongly reducing conditions. All vanadium forms are strongly bound to environmental sorbents: vanadate(V) is bound as a bidentate complex to iron, aluminium, and titanium (hydr)oxides, and with a stronger affinity than that of orthophosphate (o-phosphate). Vanadyl(IV) is strongly complexed to natural organic matter, while vanadium(III) may substitute for other trivalent ions in mineral structures. Despite this, vanadium may be mobilized to the aqueous phase, for example under high-pH conditions. Studies with V K-edge XANES spectroscopy have shown that most oxic soils usually contain a mixture of vanadium(IV) that is octahedrally coordinated in primary minerals, and surface-bound vanadate(V) on iron and aluminium (hydr)oxides, although acid organic soils are dominated by organically complexed vanadyl(IV). In reduced environments, such as in sediments and black shales, available evidence suggests that the V consists of a mixture of organically complexed vanadyl(IV) and unknown vanadium(III) species. However, considerable uncertainty exists on the V speciation under reducing conditions, and additional research is recommended.Vanadium is essential for some species of cyanolichens and algae due to its presence in vanadium nitrogenase, which can be important for N fixation in boreal ecosystems, and in vanadium haloperoxidases, which mediate the oxidation of halide, particularly iodine and bromine. In certain organisms vanadium is accumulated for unknown reasons, e.g. in ascidians, where V accumulates as a vanadium(III) complex with organic S, and in Amanita mushrooms, in which amavadin, a stable vanadium(IV)-organic complex, is accumulated. However, at high concentrations vanadium is toxic to many organisms. This is mostly due to its interference with o-phosphate in a number of biomolecules. Available evidence shows that toxic effects appear in the mg V L?1 range for most studied species. However, some organisms, i.e. algae and possibly some soil bacteria, are more sensitive. In soils, the toxic response is related to the soil solution V concentration, rather than to the solid-phase concentration. The o-phosphate concentration has been identified as a parameter that influences toxicity, but the relationship between the P status and the environmental risk of V toxicity is not yet well determined – as a result risk-based guidelines remain uncertain. There is urgent need for more research on this topic.Vanadium, being a redox-sensitive element, responds to sudden environmental change such as flooding that leads to decreased redox potential. In most, but not all, cases, an increased solubilisation of vanadium is observed after flooding, which can be attributed to reductive dissolution of vanadate(V)-sorbing iron (hydr)oxides and to vanadate(V) reduction to vanadyl(IV) that forms stable complexes with dissolved organic matter. The vanadium redox conversions are carried out by a large number of genera of bacteria. Bioremediation methods are being developed that may reduce vanadate(V) to vanadyl(IV), which may reduce the bioavailability of vanadium in many soils.Hamidi, M., Fardoust, F., Jafarzadeh, M., Rabbani, A.R., 2018. Organic geochemistry of the Upper Triassic–Middle Jurassic Shemshak Group (Alborz Mountains, NE Iran). Petroleum Science and Technology 36, 1764-1770. organic geochemistry of shale samples of Shemshak Group at Dehmolla section in Eastern Alborz Mountains in the present study are discussed throughout the Rock-Eval pyrolysis. The results used to describe the quantity, type, maturity, and petroleum potentials of the Shemshak Group sediments. The pyrolysis data show that the total organic carbon values of the shale samples are between 0.08 and 20.98?wt% and the generation potential (S1+ S2) of the studied samples ranges from 0.02 to 9.47?mg HC/g rock revealing the organic richness of these samples varies from poor to good. The type of hydrocarbon products (S2/S3) ranging from 0.06 to 2.33 and the type of hydrocarbon determined from Tmax versus HI indicate mainly well for gas generation. Based on the HI versus OI plot diagram, the type III of kerogen is the main type of organic matter in studied samples. These data also show that most of the samples were deposited in oxic environments with low sedimentation rate and high amount of organic matter from the terrestrial source. ?Tmax? values ranging from 416?°C to 602?°C in studied samples indicate that most of the samples are over mature and located in gas zone.Hamilton, W.D., Sayle, K.L., Boyd, M.O.E., Haselgrove, C.C., Cook, G.T., 2019. ‘Celtic cowboys’ reborn: Application of multi-isotopic analysis (δ13C, δ15N, and δ34S) to examine mobility and movement of animals within an Iron Age British society. Journal of Archaeological Science 101, 189-198. paper presents the results of δ13C, δ15N, and δ34S isotope analyses on archaeological faunal remains from deposits dated c. 400–200?cal BCE at two Iron Age sites in Wessex: Suddern Farm and Danebury hillfort, Hampshire. The aim was to investigate diet and mobility> within the populations and across a range of animal species. The results demonstrate a significant level of mobility within the Iron Age, with around 20% of the terrestrial herbivores either having been reared off the chalkland and brought to the sites from perhaps 150–200?km away or moving between isotopically distinct areas throughout much of their life and presenting a ‘mixed’ isotopic signal. The results lead us to suggest that the old paradigm that views most Iron Age people as leading relatively sedentary lives should be re-evaluated, and new models be considered that allow for regular movements by a portion of the population over much larger distances than hitherto considered in this period of prehistory.Hampl, V., ?epi?ka, I., Eliá?, M., 2019. Was the mitochondrion necessary to start eukaryogenesis? Trends in Microbiology 27, 96-104. based on cell energetics favour the view that a mitochondrion capable of oxidative phosphorylation was a prerequisite for the evolution of other features of the eukaryotic cell, including increased volume, genome size and, eventually, phagotrophy. Contrary to this we argue that: (i) extant amitochondriate eukaryotes possess voluminous phagotrophic cells with large genomes; (ii) picoeukaryotes demonstrate that phagotrophy is feasible at prokaryotic cell sizes; and (iii) the assumption that evolution of complex features requires extra ATP, often mentioned in this context, is unfounded and should not be used in such considerations. We claim that the diversity of cell organisations and functions observed today in eukaryotes gives no reason to postulate that a mitochondrion must have preceded phagocytosis in eukaryogenesis.Hansen, R.L., Due?as, M.E., Looft, T., Lee, Y.J., 2019. Nanoparticle microarray for high-throughput microbiome metabolomics using matrix-assisted laser desorption ionization mass spectrometry. Analytical and Bioanalytical Chemistry 411, 147-156. high-throughput matrix-assisted laser desorption/ionization mass spectrometry (MALDI)-MS-based metabolomics platform was developed using a pre-fabricated microarray of nanoparticles and organic matrices. Selected organic matrices, inorganic nanoparticle (NP) suspensions, and sputter coated metal NPs, as well as various additives, were tested for metabolomics analysis of the turkey gut microbiome. Four NPs and one organic matrix were selected as the optimal matrix set: α-cyano-4-hydroycinnamic acid, Fe3O4 and Au NPs in positive ion mode with 10?mM sodium acetate, and Cu and Ag NPs in negative ion mode with no additive. Using this set of five matrices, over two thousand unique metabolite features were reproducibly detected across intestinal samples from turkeys fed a diet amended with therapeutic or sub-therapeutic antibiotics (200?g/ton or 50?g/ton bacitracin methylene disalicylate (BMD), respectively), or non-amended feed. Among the thousands of unique features, 56 of them were chemically identified using MALDI-MS/MS, with the help of in-parallel liquid chromatography (LC)-MS/MS analysis. Lastly, as a proof of concept application, this protocol was applied to 52 turkey cecal samples at three different time points from the antibiotic feed trial. Statistical analysis indicated variations in the metabolome of turkeys with different ages or treatments.Hantsoo, K.G., Kump, L.R., Haupt, B.J., Bralower, T.J., 2018. Tracking the Paleocene-Eocene thermal maximum in the North Atlantic: A shelf-to-basin analysis with a regional ocean model. Paleoceanography and Paleoclimatology 33, 1324-1338. Paleocene-Eocene Thermal Maximum (PETM), a transient greenhouse climate interval spurred by a large release of carbon to the ocean-atmosphere approximately 56 million years ago, provides a geological point of comparison for potential effects of anthropogenic carbon emission. Geochemical proxies and fossil assemblages offer insight into the continental shelf response to the PETM, but global ocean-atmosphere models cannot resolve shelf processes at sufficient resolution for model-data comparisons. We present high-resolution simulations of the pre-PETM and PETM North Atlantic basin using the Regional Ocean Modeling System (ROMS), including a resolved continental shelf along the eastern margin of North America in the Salisbury Embayment. ROMS' high-resolution, terrain-following coordinate system permits greater vertical resolution and eddy resolution along continental margins while also capturing open-ocean processes. We find that during the PETM, benthic oxygen concentration ([O2]) in the Salisbury Embayment decreases 18% to an average state of year-round mild hypoxia, while average benthic calcite saturation (Ω) declines from 4.4 to 2.3. These benthic decreases are driven largely by enhanced benthic oxic respiration, which occurs despite no increase in shelf productivity. Instead, increased respiration stems from less vigorous off-shelf transport of organic matter due to (a) weakened along-shelf water currents and (b) weakened coastal upwelling that forces productivity closer to the shelf seafloor. Model results do not include riverine inputs, which would have further lowered benthic [O2] and Ω. Our data suggest lowered benthic calcite saturation and mild hypoxia as an upper bound on the oxygenation state of the Salisbury Embayment seafloor during the PETM.Hao, J., Mokhtari, M., Pedreira-Segade, U., Michot, L.J., Daniel, I., 2019. Transition metals enhance the adsorption of nucleotides onto clays: Implications for the origin of life. ACS Earth and Space Chemistry 3, 109-119. chemical evolution of early life requires the concentration of monomers to polymerize from the diluted primordial ocean. Transition metals such as Fe, Mn, and Zn, could have reached considerable levels in the early seawater and/or hydrothermal fluid but their influences on the adsorption of biomolecules have not been clearly addressed yet. In this study, we conducted batch adsorption experiments to explore effects of various metal cations (Li, Mg, Ca, Zn, Ni, and Mn) on the adsorption of selected nucleotides (dGMP, dAMP, and AMP) and adenosine onto nontronite and montmorillonite. We also varied the concentration of the cations and pH of the solutions to evaluate their effects. Our results show that Zn and to some extent Ni increase the adsorption of nucleotides and adenosine compared with Na, Mg, and Ca which are major salts in modern seawater. This increased adsorption is primarily attributed to the mediating role of transition metals between the clays and nucleotides and adenosine. The enhancing effect depends little on salt concentration, but strongly varies as the pH of the solution changes. Presence of transition metals reverses the declining trend of the adsorption of dGMP as the elevation of pH and strongly favors adsorption of dGMP at alkaline pH presumably through precipitation of metal-hydroxides on the clay surface. Enhanced adsorption amount of biomolecules mediated by transition metals would potentially ease the origin of life in two aspects: concentration of simple organics for polymerization and protection of early biomolecules against UV radiation and heating in early seawater.Harding, K., Turk-Kubo, K.A., Sipler, R.E., Mills, M.M., Bronk, D.A., Zehr, J.P., 2019. Symbiotic unicellular cyanobacteria fix nitrogen in the Arctic Ocean. Proceedings of the National Academy of Sciences 115, 13371-13375.: Biological dinitrogen (N2) fixation (BNF) is an important source of nitrogen in marine systems. Until recently, it was believed to be primarily limited to subtropical open oceans. Marine BNF is mainly attributed to cyanobacteria. However, recently an unusual N2-fixing unicellular cyanobacteria (UCYN-A)/haptophyte symbiosis was reported with a broader temperature range than other N2-fixing cyanobacteria. We report that the UCYN-A symbiosis is present and fixing N2 in the Western Arctic and Bering Seas, further north than any previously reported N2-fixing marine cyanobacteria. Nanoscale secondary ion mass spectrometry enabled us to directly show that the symbiosis was fixing N2. These results show that N2-fixing cyanobacteria are not constrained to subtropical waters and challenge commonly held ideas about global marine N2 fixation.Abstract: Biological dinitrogen (N2) fixation is an important source of nitrogen (N) in low-latitude open oceans. The unusual N2-fixing unicellular cyanobacteria (UCYN-A)/haptophyte symbiosis has been found in an increasing number of unexpected environments, including northern waters of the Danish Straight and Bering and Chukchi Seas. We used nanoscale secondary ion mass spectrometry (nanoSIMS) to measure 15N2 uptake into UCYN-A/haptophyte symbiosis and found that UCYN-A strains identical to low-latitude strains are fixing N2 in the Bering and Chukchi Seas, at rates comparable to subtropical waters. These results show definitively that cyanobacterial N2 fixation is not constrained to subtropical waters, challenging paradigms and models of global N2 fixation. The Arctic is particularly sensitive to climate change, and N2 fixation may increase in Arctic waters under future climate scenarios.Harrison, A.L., Mavromatis, V., Oelkers, E.H., Bénézeth, P., 2019. Solubility of the hydrated Mg-carbonates nesquehonite and dypingite from 5 to 35?°C: Implications for CO2 storage and the relative stability of Mg-carbonates. Chemical Geology 504, 123-135. Mg-carbonate minerals form during the weathering of ultramafic rocks, and can be used to store atmospheric CO2 to help combat greenhouse gas-fueled climate change. Optimization of engineered CO2 storage and prediction of the composition and stability of Mg-carbonate phase assemblages in natural and engineered ultramafic environments requires knowledge of the solubility of hydrated Mg-carbonate phases, and the transformation pathways between these metastable phases. In this study, we evaluate the solubility of nesquehonite [MgCO3·3H2O] and dypingite [Mg5(CO3)4(OH)2·(5 or 8)H2O] and the transformation from nesquehonite to dypingite between 5?°C and 35?°C, using constant-temperature, batch-reactor experiments. The logarithm of the solubility product of nesquehonite was determined to be: ?5.03?±?0.13, ?5.27?±?0.15, and ?5.34?±?0.04 at 5?°C, 25?°C, and 35?°C, respectively. The logarithm of the solubility product of dypingite was determined to be: ?34.95?±?0.58 and ?36.04?±?0.31 at 25?°C and 35?°C, respectively, with eight waters of hydration. This is the first reported dypingite solubility product. The transformation from nesquehonite to dypingite was temperature-dependent, and was complete within 57?days at 25?°C, and 20?days at 35?°C, but did not occur during experiments of 59?days at 5?°C. This phase transformation appeared to occur via a dissolution-reprecipitation mechanism; external nesquehonite crystal morphology was partially maintained during the phase transformation at 25?°C, but was eradicated at 35?°C. Together, our results facilitate the improved evaluation of Mg-carbonate mineral precipitation in natural and engineered ultramafic mineral weathering systems that sequester CO2, and for the first time allow assessment of the saturation state of dypingite in aqueous solutions.Hassanzadeh, P., Rabbani, A.R., Hezarkhani, A., Khajooie, S., 2018. Assessing lateral continuity within the Yammama reservoir in the Foroozan oilfield, offshore Iran: An integrated study. Acta Geologica Sinica - English Edition 92, 2405-2415. in Iranian sector of the Persian Gulf, Foroozan Oilfield has been producing hydrocarbons via seven different reservoirs since the 1970s. However, understanding fluid interactions and horizontal continuity within each reservoir has proved complicated in this field. This study aims to determine the degree of intra‐reservoir compartmentalization using gas geochemistry, light hydrocarbon components, and petroleum bulk properties, comparing the results with those obtained from reservoir engineering indicators. For this purpose, a total of 11 samples of oil and associated gas taken from different producing wells in from the Yammama Reservoir were selected. Clear distinctions, in terms of gas isotopic signature and composition, between the wells located in northern and southern parts of the reservoir (i.e. lighter δ13C1, lower methane concentration, and negative sulfur isotope in the southern part) and light hydrocarbon ratios (e.g. nC7/toluene, 2,6‐dmC7/1,1,3‐tmcyC5 and m‐xylene/4‐mC8) in different oil samples indicated two separate compartments. Gradual variations in a number of petroleum bulk properties (API gravity, V/Ni ratios and asphaltene concentration) provided additional evidence on the reservoir‐filling direction, signifying that a horizontal equilibrium between reservoir fluids across the Yammama Reservoir is yet to be achieved. Finally, differences in water‐oil contacts and reservoir types further confirmed the compartmentalization of the reservoir into two separate compartments.He, C., H?rst, S.M., Lewis, N.K., Moses, J.I., Kempton, E.M.R., Marley, M.S., Morley, C.V., Valenti, J.A., Vuitton, V., 2019. Gas phase chemistry of cool exoplanet atmospheres: Insight from laboratory simulations. ACS Earth and Space Chemistry 3, 39-50. induced by stellar UV flux should produce haze particles in exoplanet atmospheres. Recent observations indicate that haze and/or cloud layers exist in the atmospheres of exoplanets. However, photochemical processes in exoplanetary atmospheres remain largely unknown. We performed laboratory experiments with the PHAZER chamber to simulate haze formation in a range of exoplanet atmospheres (hydrogen-rich, water-rich, and carbon dioxide-rich at 300, 400, and 600 K), and observed the gas phase compositional change (the destruction of the initial gas and the formation of new gas species) during these experiments with mass spectrometer. The mass spectra reveal that distinct chemical processes happen in the experiments as a function of different initial gas mixture and different energy sources (plasma or UV photons). We find that organic gas products and O2 are photochemically generated in the experiments, demonstrating that photochemical production is one of the abiotic sources for these potential biosignatures. Multiple simulated atmospheres produce organics and O2 simultaneously, which suggests that even the copresence of organics and O2 could be a false positive biosignature. From the gas phase composition changes, we identify potential precursors (C2H2, HCN, CH2NH, HCHO, etc.) for haze formation, among which complex reactions can take place and produce larger molecules. Our laboratory results indicate that complex atmospheric photochemistry can happen in diverse exoplanet atmospheres and lead to the formation of new gas products and haze particles, including compounds (O2 and organics) that could be falsely identified as biosignatures.He, J., Ju, Y., Kulasinski, K., Zheng, L., Lammers, L., 2019. Molecular dynamics simulation of methane transport in confined organic nanopores with high relative roughness. Journal of Natural Gas Science and Engineering 62, 202-213. and characterizing the transport of shale gas (methane) through the nanopores of kerogens are critical for the accurate prediction of shale gas recovery. However, the key factors that regulate shale gas transport through highly roughened nanopores of shale kerogens are not fully understood. In this work, methane transport in organic nanopores with a high relative roughness is characterized using equilibrium and non-equilibrium molecular dynamics methods. According to our results, the CH4 mass flux has a linear relationship with the pressure gradient, consistent with previous studies, while the calculated slip lengths and gas fluxes varied with different roughness geometries in the order of sigmoidal?≥?triangular?>?rectangular. Surface slip flow can be a major contributor to the overall gas flux, but surprisingly, the relative contribution of surface slip flow is independent of the pressure gradient. In contrast, the contributions of both slip flow and the average gas fluxes vary strongly with pore diameters. Typical contributions of the adsorbed layer to the overall gas flux are in the range 20–40% but vary from as high as 74% in a 4-nm pore to as low as 6% in a 16-nm pore. Compared to smooth nanopores, we find that, in nanopores with realistically high degrees of relative roughness, methane confinement in cavities decouples slip flow from the flow in the pore interior, significantly reducing the overall flux.He, Y., Bao, H., 2019. Predicting high-dimensional isotope relationships from diagnostic fractionation factors in systems with diffusional mass transfer. ACS Earth and Space Chemistry 3, 120-128. dual or multiple stable isotope relationship, for example, a trajectory in a δ?δ (or δ′?δ′) space, can be used to deduce the relationship of underlying diagnostic isotope fractionation factors (α) and therefore reveal the mechanism of a reaction process. While temporal data sampled from a closed-system can be treated by a Rayleigh distillation model, spatial data should be treated by a reaction-transport model. Owing to an apparent similarity between the temporal and spatial trajectories, the research community has often ignored this distinction and applied a Rayleigh distillation model to cases where a reaction-transport model should be applied. To examine the potential error of this practice, here we compare the results of a Rayleigh distillation model to a diffusional reaction-transport model by simulating the trajectories in nitrate’s δ′18O?δ′15N space during a simple denitrification process. We found that an incorrect application of a Rayleigh distillation model can underestimate the degree of a diagnostic fractionation to 50% but results in an insignificant difference in the regression slope of a δ′?δ′ trajectory when α ≈ 1.0. The regression slope predicted by a Rayleigh distillation model can, however, be 0.03–0.3 greater than predicted by a reaction-transport model when NO3– is involved in complex nitrogen cycling. Our reaction-transport model rarely predicts a δ′18O?δ′15N regression slope > 1 for reasonable Earth surface conditions. We found that for those published cases of regression slopes > 1, many can be attributed to the grouping of multiple NO3– sources from independent origins. Our results highlight the importance of linking the underlying physical model to the plotted data points before interpreting their high-dimensional isotope relationships.Heidke, I., Scholz, D., Hoffmann, T., 2019. Lignin oxidation products as a vegetation proxy in stalagmite and drip water samples from the Herbstlabyrinth, Germany. Climate of the Past Discussions 2019, 1-23. we present the first quantitative record of lignin oxidation products (LOPs) in a Holocene stalagmite from the Herbstlabyrinth Cave in central Germany, as well as LOP results from 16 months of drip water monitoring. Lignin is only produced by vascular plants and is therefore an unambiguous vegetation proxy, which can help to better interpret other vegetation and climate proxies in speleothems. We compared our results with stable isotope and trace element data from the same samples. The drip water monitoring reveals a seasonal pattern of LOPs in a fast drip site with low LOP concentrations in winter and higher LOP concentrations in summer, which is opposite to the behaviour of the drip rate, Mg2+ and PO3?4 concentrations. In the stalagmite, LOP concentrations are correlated or show a similar behaviour to P, Ba and U concentrations. The LOP ratios C/V and S/V, which are usually used to differentiate between angiosperm and gymnosperm and woody and non-woody lignin sources, are anticorrelated to the LOP concentrations and show a similar behaviour to δ13C and Mg concentrations. These results highlight the potential of LOPs as a new, highly specific vegetation proxy in speleothems, but also demonstrate current limitations in our understanding of the transport of lignin from the soil into the cave and the speleothems.Hendrix, A.R., Hurford, T.A., Barge, L.M., Bland, M.T., Bowman, J.S., Brinckerhoff, W., Buratti, B.J., Cable, M.L., Castillo-Rogez, J., Collins, G.C., Diniega, S., German, C.R., Hayes, A.G., Hoehler, T., Hosseini, S., Howett, C.J.A., McEwen, A.S., Neish, C.D., Neveu, M., Nordheim, T.A., Patterson, G.W., Patthoff, D.A., Phillips, C., Rhoden, A., Schmidt, B.E., Singer, K.N., Soderblom, J.M., Vance, S.D., 2018. The NASA roadmap to ocean worlds. Astrobiology 19, 1-27. this article, we summarize the work of the NASA Outer Planets Assessment Group (OPAG) Roadmaps to Ocean Worlds (ROW) group. The aim of this group is to assemble the scientific framework that will guide the exploration of ocean worlds, and to identify and prioritize science objectives for ocean worlds over the next several decades. The overarching goal of an Ocean Worlds exploration program as defined by ROW is to “identify ocean worlds, characterize their oceans, evaluate their habitability, search for life, and ultimately understand any life we find.” The ROW team supports the creation of an exploration program that studies the full spectrum of ocean worlds, that is, not just the exploration of known ocean worlds such as Europa but candidate ocean worlds such as Triton as well. The ROW team finds that the confirmed ocean worlds Enceladus, Titan, and Europa are the highest priority bodies to target in the near term to address ROW goals. Triton is the highest priority candidate ocean world to target in the near term. A major finding of this study is that, to map out a coherent Ocean Worlds Program, significant input is required from studies here on Earth; rigorous Research and Analysis studies are called for to enable some future ocean worlds missions to be thoughtfully planned and undertaken. A second finding is that progress needs to be made in the area of collaborations between Earth ocean scientists and extraterrestrial ocean scientists.Hines, K.M., Xu, L., 2019. Lipidomic consequences of phospholipid synthesis defects in Escherichia coli revealed by HILIC-ion mobility-mass spectrometry. Chemistry and Physics of Lipids 219, 15-22. understanding of phospholipid biosynthesis in Gram-positive and Gram-negative bacteria is derived from the prototypical Gram-negative organism Escherichia coli. The inner and outer membranes of E. coli are largely composed of phosphatidylethanolamine (PE), minor amounts of phosphatidylglycerol (PG) and cardiolipin (CL). We report here the utility of hydrophilic interaction liquid chromatography (HILIC) paired with ion mobility-mass spectrometry (IM-MS) for the comprehensive analysis of the E. coli lipidome. Using strains with chromosomal deletions in the PG and CL synthesis genes pgsA and clsABC, respectively, we show that defective phospholipid biosynthesis in E. coli results in fatty-acid specific changes in select lipid classes and the presence of the minor triacylated phospholipids, acylphosphatidyl glycerol (acylPG) and N-acylphosphatidylethanolamine (N-acylPE). Notably, acylPGs were accumulated in the clsABC-KO strain, but were absent in other mutant strains. The separation of 1-lyso and 2-lyso-phosphatidylethanolamines (lysoPEs) is demonstrated in both the HILIC and IM dimensions. Using our previously validated calibration method, collision cross section values of nearly 200 phospholipids found in E. coli were determined on a traveling wave IM-MS platform, including newly reported values for cardiolipins, positional isomers of lysoPEs, acylPGs and N-acylPEs.Hofmann, R., Tietje, M., Aberhan, M., 2019. Diversity partitioning in Phanerozoic benthic marine communities. Proceedings of the National Academy of Sciences 116, 79-83.: Biotic interactions are drivers of biodiversity, yet their effects on Phanerozoic marine diversity remain elusive because they operate on small spatial scales. We provide the comprehensive reconstruction of within-community, between-community, and overall diversity on the scale of geological formations throughout the Phanerozoic eon to gauge the effects of biotic interactions on biodiversity. Within-community and overall diversity are positively correlated and both are practically unbounded. Between-community diversity drives overall diversity only at low levels of overall diversity, and mostly during the early- to mid-Paleozoic. Further increase of biodiversity is generally achieved by finer resource partitioning driven by positive species interactions.Abstract: Biotic interactions such as competition, predation, and niche construction are fundamental drivers of biodiversity at the local scale, yet their long-term effect during earth history remains controversial. To test their role and explore potential limits to biodiversity, we determine within-habitat (alpha), between-habitat (beta), and overall (gamma) diversity of benthic marine invertebrates for Phanerozoic geological formations. We show that an increase in gamma diversity is consistently generated by an increase in alpha diversity throughout the Phanerozoic. Beta diversity drives gamma diversity only at early stages of diversification but remains stationary once a certain gamma level is reached. This mode is prevalent during early- to mid-Paleozoic periods, whereas coupling of beta and gamma diversity becomes increasingly weak toward the recent. Generally, increases in overall biodiversity were accomplished by adding more species to local habitats, and apparently this process never reached saturation during the Phanerozoic. Our results provide general support for an ecological model in which diversification occurs in successive phases of progressing levels of biotic interactions.Hogle, S.L., Dupont, C.L., Hopkinson, B.M., King, A.L., Buck, K.N., Roe, K.L., Stuart, R.K., Allen, A.E., Mann, E.L., Johnson, Z.I., Barbeau, K.A., 2019. Pervasive iron limitation at subsurface chlorophyll maxima of the California Current. Proceedings of the National Academy of Sciences 115, 13300-13305.: The vertical distribution of phytoplankton cells and chlorophyll concentrations throughout the sunlit water column is rarely uniform. In many ocean regions, chlorophyll concentrations peak in distinct and persistent layers deep below the surface called subsurface chlorophyll maximum layers (SCMLs). SCML formation is hypothesized to reflect the consequences of phytoplankton light/macronutrient colimitation, behavior, and/or photoacclimation. We discovered unexpectedly persistent and widespread phytoplankton iron limitation and iron/light colimitation in SCMLs of the California Current and at the edge of the North Pacific Subtropical Gyre using shipboard incubations, metatranscriptomics, and biogeochemical proxies. These results suggest that interactions and feedbacks between iron and light availability play an important and previously unrecognized role in controlling the productivity and biogeochemical dynamics of SCMLs.Abstract: Subsurface chlorophyll maximum layers (SCMLs) are nearly ubiquitous in stratified water columns and exist at horizontal scales ranging from the submesoscale to the extent of oligotrophic gyres. These layers of heightened chlorophyll and/or phytoplankton concentrations are generally thought to be a consequence of a balance between light energy from above and a limiting nutrient flux from below, typically nitrate (NO3). Here we present multiple lines of evidence demonstrating that iron (Fe) limits or with light colimits phytoplankton communities in SCMLs along a primary productivity gradient from coastal to oligotrophic offshore waters in the southern California Current ecosystem. SCML phytoplankton responded markedly to added Fe or Fe/light in experimental incubations and transcripts of diatom and picoeukaryote Fe stress genes were strikingly abundant in SCML metatranscriptomes. Using a biogeochemical proxy with data from a 40-y time series, we find that diatoms growing in California Current SCMLs are persistently Fe deficient during the spring and summer growing season. We also find that the spatial extent of Fe deficiency within California Current SCMLs has significantly increased over the last 25 y in line with a regional climate index. Finally, we show that diatom Fe deficiency may be common in the subsurface of major upwelling zones worldwide. Our results have important implications for our understanding of the biogeochemical consequences of marine SCML formation and maintenance.Hou, X., Zhu, Y., Jiang, Z., Gao, H., 2018. Geological models and controlling factors of gas content in marine–terrigenous shale in the Southern Qinshui Basin, China. Energy Exploration & Exploitation 37, 375-393. prediction models for gas content in marine?terrigenous shale under the effects of reservoir characteristics and in situ geological conditions, were established using methane isothermal adsorption, high temperature/pressure methane isothermal adsorption, total organic carbon, X-ray diffraction, mercury porosimetry, porosity in net confining stress, and field desorption methods. Results indicated that the adsorption capacity of marine?terrigenous shale has a linearly positive correlation with total organic carbon content and maturity. Clay and quartz minerals are the two main components of inorganic minerals in marine?terrigenous shale, with an average content of 54.3% and 36.9%, respectively. Adsorption capacity of marine?terrigenous shale is slightly positive correlated with clay content, while it exponentially decreases with increasing quartz content. The effects of in situ temperature and reservoir pressure on adsorption capacity in marine?terrigenous shale are also significant. The adsorption capacity of marine?terrigenous shale shows a clear decreasing trend as temperature increases, while it increases with increasing reservoir pressure. The porosity of marine?terrigenous shale is characterized by highly stress-sensitive, decreasing exponentially with increasing effective stress, which results in a more complex occurrence of free gas in deep shale reservoirs. In addition, gas saturation for the shale samples was calculated based on the results of field desorption, after which geological prediction models of total gas, adsorbed gas, and free gas were established while considering the coupled effects. Adsorbed gas, free gas, and total gas content all initially increase as burial depth increases, and then eventually decrease. Adsorbed gas content and free gas content have a positive correlation with total organic carbon content and porosity, indicating that the total gas content at different burial depths is mainly controlled by the total organic carbon content and porosity.Hou, Z., Xiong, X., Fang, X., Huang, G., 2019. Enhanced desorption electrospray ionization mass spectrometry via synchronizing ion generation and ion injection. Journal of The American Society for Mass Spectrometry 30, 368-375. modified version of desorption electrospray ionization mass spectrometry was developed for (i) better utilization of analyte ions and (ii) larger sampling area via synchronization the pulsed nebulizer gas with ion injection. To synchronize the sheath gas, gas flow was paused for 50?ms within each cycle, leading to solvent accumulation at the end of emitter tip. That solvent accumulation enlarged the desorption areas. As a result, the amount of analytes increased. Thus, the improved signal intensity (~?2–5-folds for various substrates) was benefit from both better analyte ion utilization and larger desorption areas. Finally, the enhanced signal intensity was confirmed with both garlic homogenate and brain homogenate.Hough, S.E., Bilham, R., 2018. Revisiting earthquakes in the Los Angeles, California, Basin during the early instrumental period: Evidence for an association with oil production. Journal of Geophysical Research: Solid Earth 123, 10,684-10,705.: A total of 7 independent ML≥4.0 earthquakes occurred in the Los Angeles, California, basin, during the early instrumental period between 1932 and 1952, the largest of which was the 1933 Long Beach earthquake. Revising available macroseismic and instrumental data for a total of 6 4.0≤ ML≤5.1 events between 1938 and 1944, we conclude that early instrumental locations can be grossly inconsistent with detailed macroseismic data. We use available macroseismic data to revisit event locations. We further present evidence that most if not all of these moderate earthquakes may have been induced by oil production. We quantify the predicted stress change associated with production from eight oil fields in the southwestern Los Angeles basin and show that frictional failure would have been encouraged beneath and at the periphery of high‐volume fields, with stress changes upwards of 0.1 MPa at 5 km depth. The results suggest that, if earthquakes are induced by stress changes associated with production, the magnitudes of events might tend to be limited by the limited spatial extent of lobes of increased stress. It further appears that the advent of fluid injection recovery methods (“water‐flooding”) around 1960 mitigated induced earthquake risk considerably. Plain Language Summary: We reconsider the locations and magnitudes of six moderate earthquakes that occurred in the Los Angeles region between 1935 and 1950. We show that, while these earthquakes were recorded by early seismometers, detailed damage observations provide a better indication of locations than do limited instrumental data. We further present evidence for an association between these earthquakes and oil production during the oil boom that began in the late 1930s. Using available industry data and established computation methods, we show that, by the 1930s, oil production would have perturbed significantly the stress and faults in proximity to major fields at depths of 3‐5 km. We suggest that the extent and therefore magnitude of induced earthquakes would have been generally limited by the spatially complex patterns of stress change. We further suggest that induced earthquake risk was mitigated significantly by the advent of so‐called secondary recovery methods, whereby water was reinjected into fields to compensate for oil extraction.Hu, G., Meng, Q., Wang, J., Tengger, Xie, X., Lu, L., Luo, H., Liu, W., 2018. The original organism assemblages and kerogen carbon isotopic compositions of the Early Paleozoic source rocks in the Tarim Basin, China. Acta Geologica Sinica - English Edition 92, 2297-2309. organisms are the biological precursors of organic matter in source rocks. Original organisms in source rocks are informative for oil‐source rock correlation and hydrocarbon potential evaluation, especially for source rocks which have high‐over level of thermal maturity. Systematic identification of original organism assemblages of the Lower Paleozoic potential source rocks and detailed carbon isotopic composition of kerogen analyses were conducted for four outcrop sections in the Tarim basin. Results indicated that the original organism assemblages of the lower part of the Lower Cambrian were composed mainly of benthic algae, whereas those of the Upper Cambrian and the Ordovician were characterized by planktonic algae. Kerogen carbon isotopic data demonstrated that the δ13Ckerogen values of source rocks dominated by benthic algae are lower than –34‰, whereas the δ13Ckerogen values of source rocks dominated by planktonic algae are higher than –30‰ in general. We tentatively suggested that the carbon species those are utilized by algae and the carbon isotopic fractionation during photosynthesis are the major controls for the δ13Ckerogen values in the Lower Paleozoic source rocks in the Tarim basin. Correlating the δ13C values of oils exploited in the Tarim basin, the original organism assemblages, and δ13Ckerogen values of source rocks, it implied that the Lower Paleozoic oils exploited in the Tarim basin should be sourced from the source rocks with original organism assemblages dominated by planktonic algae, and the hydrocarbon sourced from the Cambrian benthic algae should be of great exploration potential in future. Original organism assemblages in source rocks can provide important clues for oil‐source rocks correlation, especially for the source rocks with high thermal maturity.Huang, T., Armbruster, M.R., Coulton, J.B., Edwards, J.L., 2019. Chemical tagging in mass spectrometry for systems biology. Analytical Chemistry 90, 109-125. spectrometry (MS) offers unparalleled qualitative and quantitative chemical information. While increasingly considered a universal detector, the limitations of MS to charged analytes requires that the analyte have a moiety which can readily accept a charge. To augment analyte charge state or hydrophobicity, chemical derivatization (i.e., chemical tagging or labeling) is often used to introduce groups which adjust the analyte’s physical properties, increasing detection and sensitivity. Chemical tagging takes advantage of discrete chemistries to bring high proton affinity groups, hydrophobicity, or UV absorbing tags to desired analytes. These tags can be applied discretely to distinct groups which offer selectivity or more broadly for universal detection depending on the end goal of the user. The benefits of chemical tagging are substantial. For quantitative analysis, the signal can be improved 102- to 103-fold depending on the type of tag. This is especially beneficial for charge resistant or low abundance analytes. The majority of chemical tagging is done to mitigate quantitation hurdles inherent with both electrospray ionization and matrix assisted laser desorption ionization (ESI and MALDI, respectively). Quantitative chemical tagging can only be achieved when the reactions are consistent with uniform reaction efficiencies. The surest way to achieve this is to reach reaction yields that are reproducibly high (>95%). Interest in qualitative information, particularly of proteins, has accelerated in recent years. Chemical tagging of proteins to elucidate structural information or protein interactions will continue to drive versatile tagging applications on biochemical investigations. These new methods allow for structural characterization of various proteins, particularly biotherapeutics, such as antibodies. Qualitative reactions do not require the stringent quantitative yields as described above unless the scheme aims to offer both qualitative and quantitative data. This review introduces (1) fundamental reactions commonly used in MS-based chemical tagging, (2) various types of chemical tags used, and (3) application areas where tags have made the most headway, particularly in bioanalytical chemistry and -omics-based systems biology. Special emphasis is placed on works from the past five years. This review does not include ion–ion reactions or reactions such as silylation for gas chromatography, which is generally considered a mature reaction technique. MS-based -omics approaches have grown over the past five years largely due to innovations in chemical tagging. This trend is expected to continue as demand for better quantitation and higher throughput place financial and time pressures on high end instrumentation such as MS. As MS analyses grows into new fields, the desire for more versatile and robust methods will drive the direction of chemical tagging.Huang, X.-H., Zheng, X., Chen, Z.-H., Zhang, Y.-Y., Du, M., Dong, X.-P., Qin, L., Zhu, B.-W., 2019. Fresh and grilled eel volatile fingerprinting by e-Nose, GC-O, GC–MS and GC?×?GC-QTOF combined with purge and trap and solvent-assisted flavor evaporation. Food Research International 115, 32-43. and grilled eel were investigated with respect to their volatile compounds and different fingerprinting techniques. An electronic nose (e-Nose) was applied to distinguish the odor between fresh and grilled eels. Purge and trap (P&T) and solvent-assisted flavor evaporation (SAFE) method were used to extract volatile compounds and further analyzed by a gas chromatographic combined with quadrupole mass spectrometry (GC–MS) and a two-dimensional gas chromatographic combined with hybrid quadrupole time-of-flight mass spectrometry (GC?×?GC-QTOF). SAFE extracted more ketone, alcohol and high boiling volatiles in eels than P&T. Considering some distinct compounds extracted by P&T, a P&T and SAFE combined method was chosen. There were 155 volatiles detected in fresh and grilled eels, 93 volatiles were identified. Due to the higher peak capacity, GC?×?GC-QTOF detected 39 compounds more than GC–MS. The key characteristic volatiles of grilled eel were methyl propyl disulfide, dimethyl trisulfide, heptane, octane, and camphene. Volatile fingerprinting can be a reference benchmark for identification and quality appraisal of fresh and grilled eel products.Huang, X., Meyers, P.A., 2019. Assessing paleohydrologic controls on the hydrogen isotope compositions of leaf wax n-alkanes in Chinese peat deposits. Palaeogeography, Palaeoclimatology, Palaeoecology 516, 354-363. high concentrations of lipid biomarkers in peat and the close relation between peatland development and hydrological conditions merit further assessment of the paleohydrological proxy potential of the 2H/1H ratio of leaf wax n-alkanes (δ2Halk) in peat deposits. In the context of the dynamics of the East Asian summer monsoon, detailed investigation of modern processes is an important way to improve our understanding of the controls on δ2Halk records from Chinese peat deposits. This review first synthesizes the results of investigations of modern processes in the Dajiuhu peatland of central China, complemented by results from other peatlands and nearby non-peatland sites, to evaluate how the 2H/1H ratio changes from source water to leaf water and then to lipids in leaf waxes and ultimately to peat deposits. The results reveal that the precipitation δ2H values and the peatland plant types are the two major factors that control the δ2Halk signals preserved in peat at Dajiuhu. Comparison of results from Holocene δ2Halk sequences from other Chinese peat deposits illustrates how peat δ2Halk values respond to paleoclimate changes on centennial to millennial timescales throughout the East Asian summer monsoon region. Finally, proposed incubations of peat-forming plants in controlled chambers that could assess the response of plant δ2Halk values to environmental stresses are described. As an example, responses of the compound-specific biomarker δ2H and δ13C values of Sphagnum, the dominant plant in the Dajiuhu peatland, could provide important information on the symbiotic relation between Sphagnum and microbes. It is expected that experiments such as these that combine the carbon and hydrogen isotope compositions of multiple lipids will yield important new insights into the responses of peatland ecosystems to climate changes.Hueter, A., Huck, S., Bodin, S., Heimhofer, U., Weyer, S., Jochum, K.P., Immenhauser, A., 2019. Central Tethyan platform-top hypoxia during Oceanic Anoxic Event 1a. Climate of the Past Discussions 2019, 1-26. hypoxia in epeiric water masses is a common phenomenon of modern marine environments and causes mass mortality in coastal marine ecosystems. Here, we test the hypothesis that during the Early Aptian, platform-top hypoxia temporarily established in some of the vast epeiric seas of the Central Tethys and caused, combined with other stressors, significant changes in reefal ecosystems. Potentially interesting target examples include time intervals characterized by the demise of Lower Aptian rudist-coral communities and the establishment of microencruster facies as previously described from the Central and Southern Tethys and from the proto-North Atlantic domain. These considerations are relevant as previous work has predominantly focused on Early Aptian basinal anoxia in the context of the Oceanic Anoxic Event (OAE) 1a, whereas the potential expansion of the oxygen minimum zone in coeval shallow water environments is underexplored. Well known patterns in the δ13C record during OAE 1a allow for a sufficiently time-resolved correlation with previously studied locations. This paper presents and critically discusses the outcome of a multi-proxy study (e.g., REE, U isotopes and redox sensitive trace elements) applied to Lower Aptian shallow water carbonates today exposed in the Kanfanar Quarry in Istria, Croatia. These rocks were deposited on an extensive, isolated high in the Central Tethys surrounded by hemi-pelagic basins. Remarkably, during chemostratigraphic segment C2, the depletion of redox sensitive trace elements As, V, and Mo in platform carbonates, deposited in normal marine oxic waters, record the first occurrence of basinal, organic rich sediment deposition in which these elements are enriched. During the C3 segment, seawater oxygen depletion establishes on the platform top as indicated by the patterns in Ce/Ce* and uranium isotopes. Shifts in redox sensitive proxies coincide with the expansion of microencruster facies. Segment C4 witnesses the return to normal marine reefal faunas on the platform top and is characterized by patterns in redox sensitive proxies typical of normal marine dissolved oxygen levels. It remains unclear, if platform-top hypoxia resulted from the expansion and upwelling of basinal, oxygen-depleted water masses, or if spatially isolated, shallow hypoxic water bodies formed on the platform. Data shown here are relevant as they shed light on the driving mechanisms that control poorly understood faunal patterns during OAE1a in the neritic realm and provide evidence on the intricate relation between basinal and platform-top water masses.Hunt, L.J., Duca, D., Dan, T., Knopper, L.D., 2019. Petroleum hydrocarbon (PHC) uptake in plants: A literature review. Environmental Pollution 245, 472-484. oil and its constituents can have adverse effects on ecological and human health when released into the environment. The Canadian Council of Ministers of the Environment (CCME) has developed remedial guidelines and a risk assessment framework for both ecological and human exposure to PHC. One of the assumptions used in the derivation of these guidelines is that plants are unable to take up PHC from contaminated soil and therefore subsequent exposure at higher trophic levels is not a concern. However, various studies suggest that plants are indeed able to take up PHC into their tissues. Consumption of plants is a potential exposure pathway in both ecological (e.g., herbivorous and omnivorous birds, and mammals) and human health risk assessments. If plants can uptake PHC, then the current approach for risk assessment of PHC may underestimate exposures to ecological and human receptors. The present review aims to assess whether or not plants are capable of PHC uptake and accumulation. Twenty-one articles were deemed relevant to the study objective and form the basis of this review. Of the 21 primary research articles, 19 reported detectable PHC and/or its constituents in plant tissues. All but five of the 21 articles were published after the publication of the CCME Canada-Wide Standards. Overall, the present literature review provides some evidence of uptake of PHC and its constituents into plant tissues. Various plant species, including some edible plants, were shown to take up PHC from contaminated soil and aqueous media in both laboratory and field studies. Based on the findings of this review, it is recommended that the soil-plant-wildlife/human pathway should be considered in risk assessments to avoid underestimating exposure and subsequent toxicological risks to humans and wildlife.Huo, Z., Gao, Y., Zhao, Y., Zheng, T., Zhang, J., Ding, J., 2019. Evolution and recovery of original total organic carbon for muddy source rocks with different total organic carbon in the Western Sichuan Depression, Sichuan Basin, China. Geosciences Journal 23, 87-99. to the new quantitative model for original total organic carbon (TOCo) evolution and recovery of source rocks, The TOCo evolution of muddy source rocks with different TOCs (MSRDTOC) (0.5% < TOC ≤ 1.5%, 2.5% < TOC ≤ 3.5% and 4.0% < TOC ≤ 6.0%, and their average values were 1.0%, 3.0% and 5.0%, respectively) and type III kerogen were investigated in the Western Sichuan Depression (WSD) of Sichuan Basin, China, finally recovery coefficients of TOCo were calculated. Studies showed that TOCo evolution of the MSRDTOC have similarities and differences. The similarities reveal that with the increase of thermal evolution level, varied TOC all reduce gradually and the sharp reduction occurs at the stage of a large number of hydrocarbon generation and expulsion (0.7% ≤ vitrinite reflectance (VR) ≤ 1.3%). The differences indicate that the starting time and decrease range for varied TOC are different. For TOCo = 1.0%, 3.0% and 5.0%, their starting time of TOC reduction are VR = 1.05%, 0.80% and 0.60%, respectively. When VR reaches to 3.0%, their TOC decrease ranges are 30.54%, 38.52% and 44.00% and their recovery coefficients are 1.44, 1.63 and 1.79, respectively. The higher the TOC is, the earlier the starting time of TOC reduction is, the bigger the range of TOC reduction and recovery coefficient are. It must restore TOCo when we evaluate source rocks at high-over mature stage and predict oil and gas resources. The MSRDTOC and their TOCo recovery should be evaluated, respectively.Hurtig, N.C., Georgiev, S.V., Stein, H.J., Hannah, J.L., 2019. Re-Os systematics in petroleum during water-oil interaction: The effects of oil chemistry. Geochimica et Cosmochimica Acta 247, 142-161. Re-Os geochronometer can be applied to date petroleum, which is the end product of complex natural processes. Improved interpretation of natural Re-Os datasets requires identification of key controlling factors for Re-Os systematics and their isotopic imprint in oils. Here, we focus on the role of water in (re)setting the Re-Os geochronometer in oils, as formation waters and oils often coexist in basinal systems. To quantify Re-Os systematics during water-oil interaction, we performed a series of equilibration experiments between different oils and dilute aqueous solutions doped with Re and Os. The investigated parameters include the oil composition, water to oil ratio, interaction time and the initial Re-Os content in the aqueous solution. In experiments performed across a high concentration gradient, the oils fully homogenized with respect to their Os isotopic composition but had variable 187Re/188Os ratios. This indicates that the Re-Os geochronometer has been reset during water-oil interaction. However, in experiments investigating partial isotopic overprint, the crude oil and its maltene and asphaltene fractions preserved their isochron-derived age. Thus, the Re-Os radiometric clock of a single crude oil sample remains intact, even during partial equilibration of the 187Os/188Os ratio. These experimental findings provide a new foundation for interpretation of Re-Os systematics in natural water-hydrocarbon systems.Hyland, E.G., Sheldon, N.D., Smith, S.Y., Str?mberg, C.A.E., 2018. Late Miocene rise and fall of C4 grasses in the western United States linked to aridification and uplift. GSA Bulletin 131, 224-234. grasslands are a major global ecosystem with an important role as the primary source of food resources and agricultural land for the planet. Despite this, the causes and timeline of their expansion are still not fully known and appear to be variable in different parts of the world. By combining phytolith and stable isotope methods, we produce robust estimates of late Miocene C4 vegetation composition and compile a regional vegetation record through time from the late Miocene through present in southwestern Montana (USA). These estimates indicate the fairly rapid rise of C4 grasses to peak levels during the late Miocene (Hemphillian) and subsequent decline to moderate levels from the Pliocene through Present. This temporal pattern indicates significant interplay between climatic and tectonic drivers, with the late Miocene rise of C4 grasses triggered by regional aridification, and the return to lower (modern) abundances due to ecosystem restrictions linked to recent regional uplift driven by mantle buoyancy associated with the Yellowstone hotspot.Ieda, T., Hashimoto, S., Isobe, T., Kunisue, T., Tanabe, S., 2019. Evaluation of a data-processing method for target and non-target screening using comprehensive two-dimensional gas chromatography coupled with high-resolution time-of-flight mass spectrometry for environmental samples. Talanta 194, 461-468. evaluated the possibility of semi-automatic target and non-target screening by comprehensive two-dimensional gas chromatography coupled with high-resolution time-of-flight mass spectrometry (GC×GC-HRToFMS) by using estuarine sediment samples. Two-way screening consisting of compound-based (target screening) and data-based (non-target screening) analyses was performed by using two original software programs, including mass-spectral deconvolution software based on non-negative matrix factorization, the NIST Mass Spectral Library, and an in-house accurate mass spectral library with a retention index (RI) for the 1st column. Target screening detected 47 organohalogen compounds, including polychlorinated biphenyls, polybrominated diphenyl ethers and organochlorine pesticides, in the sediment sample. Among about 54,000 peaks detected in the non-target screening, 53.6% showed match factors (MF) of ≥?700 in an automatic mass spectral library search using the peak-top mass spectra. Both mass error of molecular ions and RI error were calculated automatically for the first-hit compounds in the library search; 0.03% of peaks passed all criteria, namely MF?≥?700, mass error?≤±?20?ppm, RI error?≤?±?20, and intensity of molecular ion?≥?10,000. Two compounds—a phosphorus flame retardant and a brominated phenol—were tentatively identified in the non-target screening process. The advantages of semi-automatic GC×GC-HRToFMS data processing with the two original software programs is its simplicity, high reproducibility, and shortened time for processing a large volume data. The results suggest that an In-source HiRes search—i.e. library matching using accurate mass spectra—is useful and could be applied for non-target screening using high-resolution MS in the future.Iguiniz, M., Corbel, E., Roques, N., Heinisch, S., 2019. Quantitative aspects in on-line comprehensive two-dimensional liquid chromatography for pharmaceutical applications. Talanta 195, 272-280. comprehensive two-dimensional liquid chromatography (on-line LCxLC) is expected to offer impressive effective peak capacity. That makes it an attractive technique for the analysis of complex samples such as pharmaceuticals, for which impurities are often unknown both in number and in structure, and can be either totally different or similar to the active substance. A study on comprehensive on-line RPLCxRPLC (reversed phase liquid chromatography in both dimensions) with respect to quantitative aspect at low concentration levels was carried out with the objective of finding conditions able to meet regulatory requirements for the control of pharmaceutical impurities. Preliminary studies showed that the best approach for quantitative purpose was to relate the impurity concentration to the sum of the second dimension peak areas. RPLCxRPLC conditions were optimized according to a Pareto-optimality approach with a focus on sensitivity, thereby favouring low dilution factor. The resulting RPLCxRPLC separation led to a detection limit below 0.05% for impurities (compared with API). Furthermore, the properties of this analytical method was found to be satisfying in terms of linearity (R2 > 0.999), repeatability (RSD < 1% for second dimension retention times) and precision (RSD < 1.5% for the sum of second dimension peak areas). Finally, this on-line RPLCxRPLC approach was applied to the analysis of a batch of drug substance in the early stages of drug development. The method was able to detect impurities at concentrations as low as 0.04% (signal-to-noise ratio of 3). All these results clearly demonstrate the power of on-line RPLCxRPLC for the quantitative analysis of pharmaceutical samples.Irvine, B., Erdal, Y.S., Richards, M.P., 2019. Dietary habits in the Early Bronze Age (3rd millennium BC) of Anatolia: A multi-isotopic approach. Journal of Archaeological Science: Reports 24, 253-263. paper presents the results of isotopic analysis for dietary reconstruction of humans and animal remains from several prehistoric (3500–2000?BCE) populations in Anatolia. The investigated sites are ?kiztepe (north Anatolia, Samsun region, on the Black Sea coast), Titri? H?yük (south east Anatolia, Urfa region), Badema?ac? (south Anatolia, Antalya region), and Bakla Tepe (south west Anatolia, in the ?zmir region). This research utilises the results of stable isotope analyses of carbon (δ13C), nitrogen (δ15N), and sulphur (δ34S) in bone collagen from over 200 human and animal samples in conjunction with published archaeological, archaeobotanical, and archaeozoological data (where present) to address this issue. This study, for the first time, has permitted a wider observation of Early Bronze Age dietary habits and subsistence strategies across the region, as well as examining the nature of dietary habits on an intra- and inter-site level, and temporally across the 3rd millennium BC. The results show that during the EBA in Anatolia there was a general degree of homogeneity in dietary habits at an intra- and inter-site and regional level and across the millennium of the EBA with diets being predominantly terrestrial C3 based.Jacobs, Z., Li, B., Shunkov, M.V., Kozlikin, M.B., Bolikhovskaya, N.S., Agadjanian, A.K., Uliyanov, V.A., Vasiliev, S.K., O’Gorman, K., Derevianko, A.P., Roberts, R.G., 2019. Timing of archaic hominin occupation of Denisova Cave in southern Siberia. Nature 565, 594-599. Altai region of Siberia was inhabited for parts of the Pleistocene by at least two groups of archaic hominins—Denisovans and Neanderthals. Denisova Cave, uniquely, contains stratified deposits that preserve skeletal and genetic evidence of both hominins, artefacts made from stone and other materials, and a range of animal and plant remains. The previous site chronology is based largely on radiocarbon ages for fragments of bone and charcoal that are up to 50,000 years old; older ages of equivocal reliability have been estimated from thermoluminescence and palaeomagnetic analyses of sediments, and genetic analyses of hominin DNA. Here we describe the stratigraphic sequences in Denisova Cave, establish a chronology for the Pleistocene deposits and associated remains from optical dating of the cave sediments, and reconstruct the environmental context of hominin occupation of the site from around 300,000 to 20,000 years ago.Jalil, S., Ahmadreza, R., 2018. Characteristics of the first occurrence of Jurassic petroleum in the Zagros Basin, Iran. Acta Geologica Sinica - English Edition 92, 2280-2296. two well tests in the Asmari well#A, located in the North Dezful zone, it was concluded that in the Jurassic Mus/Alan/Neyriz and Upper Sargelu reservoirs, highly mature colorless oil and gas were trapped, including 4%–6% H2S. The alternation of Garau shale and the Gotnia anhydrite seal was so efficient that it did not allow the upward migration of petroleum from Jurassic reservoirs to higher levels. Descriptive ratios, chromatograms, pick correlation and cross plots demonstrated that the oil and gas have been derived from a TOC‐enriched sequence, consisting of the base of the Garau and the top of the Sargelu Formations. This highly organic matter‐rich sequence is traceable as an oil shale in other parts of the North Dezful zone, such as the Gashun section. The petroleum accumulations in both reservoirs are identical, have the same maturity and the same source. Diagrams of δ13C2 versus δ13C3, δ13C1 versus wetness of gas (C1/C2+C3) and δ13C1 versus δDC1 suggest that the gas is derived from a highly mature source. There are indications of TSR effects on the original petroleum that could have changed the volumetric and isotopic composition of the oil and gas. This result requires more careful study of the petroleum components to be undertaken.Jameson, E., Stephenson, J., Jones, H., Millard, A., Kaster, A.-K., Purdy, K.J., Airs, R., Murrell, J.C., Chen, Y., 2019. Deltaproteobacteria (Pelobacter) and Methanococcoides are responsible for choline-dependent methanogenesis in a coastal saltmarsh sediment. The ISME Journal 13, 277-289. saltmarsh sediments represent an important source of natural methane emissions, much of which originates from quaternary and methylated amines, such as choline and trimethylamine. In this study, we combine DNA stable isotope probing with high throughput sequencing of 16S rRNA genes and 13C2-choline enriched metagenomes, followed by metagenome data assembly, to identify the key microbes responsible for methanogenesis from choline. Microcosm incubation with 13C2-choline leads to the formation of trimethylamine and subsequent methane production, suggesting that choline-dependent methanogenesis is a two-step process involving trimethylamine as the key intermediate. Amplicon sequencing analysis identifies Deltaproteobacteria of the genera Pelobacter as the major choline utilizers. Methanogenic Archaea of the genera Methanococcoides become enriched in choline-amended microcosms, indicating their role in methane formation from trimethylamine. The binning of metagenomic DNA results in the identification of bins classified as Pelobacter and Methanococcoides. Analyses of these bins reveal that Pelobacter have the genetic potential to degrade choline to trimethylamine using the choline-trimethylamine lyase pathway, whereas Methanococcoides are capable of methanogenesis using the pyrrolysine-containing trimethylamine methyltransferase pathway. Together, our data provide a new insight on the diversity of choline utilizing organisms in coastal sediments and support a syntrophic relationship between Bacteria and Archaea as the dominant route for methanogenesis from choline in this environment.Jeffrey, L.C., Maher, D.T., Johnston, S., Maguire, K., Steven, A.D.L., Tait, D.R., 2019. Rhizosphere to the atmosphere: contrasting methane pathways, fluxes and geochemical drivers across the terrestrial-aquatic wetland boundary. Biogeosciences Discussions 2019, 1-33. wetlands represent the largest natural source of atmospheric CH4, large uncertainties remain regarding the global CH4 flux. Wetland hydrological oscillations contribute to this uncertainty, dramatically altering wetland area, water table height, soil redox potentials and CH4 emissions. This study compares both terrestrial and aquatic CH4 fluxes over two distinct seasons in both permanent and seasonal remediated freshwater wetlands in subtropical Australia. We account for aquatic CH4 diffusion and ebullition rates, and plant-mediated CH4 fluxes from three distinct vegetation communities, thereby examining seasonal, diurnal and intra-habitat variability. CH4 emission rates were related to underlying sediment geochemistry. For example, distinct negative relationships between Fe(III) and SO42? and CH4 fluxes were observed, whereas distinct positive trends occurred between CH4 emissions and Fe(II)/AVS, where sediment Fe(III) and SO42? were depleted. The highest CH4 emissions of the seasonal wetland were measured during flooded conditions and always during daylight hours, which is consistent with soil redox potential and temperature being important co-drivers of CH4 flux. The highest CH4 fluxes were consistently emitted from the permanent wetland (1.5 to 10.5mmolm?2d?1), followed by the Phragmites australis community within the seasonal wetland (0.8 to 2.3mmolm?2d?1), whilst the lowest CH4 fluxes came from a region of forested Juncus sp. (?0.01 to 0.1mmolm?2d?1) which also corresponded with the highest sedimentary Fe(III) and SO42?. We suggest that wetland remediation strategies should consider geochemical profiles to help to mitigate excessive and unwanted methane emissions, especially during early system recovery periods.Ji, C.-X., Yang, G.-P., Chen, Y., Zhang, P.-Y., 2019. Distribution, degradation and bioavailability of dissolved organic matter in the East China Sea. Biogeochemistry 142, 189-207. samples were collected from the East China Sea (ECS) in October 2015 to investigate the distribution, degradation and bioavailability of organic matter. Concentrations of dissolved organic carbon (DOC), total hydrolyzable amino acids (THAAs, including dissolved free, DFAA and combined fraction, DCAA), particulate amino acids (PAAs), and total dissolved carbohydrates (TDCHO, including monosaccharides, MCHO and polysaccharides, PCHO) were measured. DOC and TCHO concentrations exhibited similar distribution patterns with high values occurring at nearshore stations, revealing the effects of terrestrial input and similar source and removal pathways of DOC and TCHO. The distributions of THAA, DCAA, and PAA displayed declining trends from the north to south of the ECS. Elevated THAA values simultaneously occurred in the center of the transect. The onboard incubation experiments with surface seawater from one station showed that the values of degradation index based on amino acids decreased with the increase of dissolved inorganic nitrogen (DIN) concentrations, indicating the mineralization of THAA to DIN during degradation process. TCHO-C% and THAA-C% are defined as the percentages of carbohydrates and amino acids in DOC, respectively. There were 21 stations suffering P limitation, implying that PO43?-P content was the key factor limiting the growth of phytoplankton. High TCHO-C% values were found at P-limited stations, indicating that phytoplankton preferentially produced carbohydrates when experiencing nutrient limitation. The difference of dissolved organic matter bioavailability between surface and bottom water were probably due to water stratification. Overall, the present study may have implications for the source, removal and bioavailability of organic mater in the ECS.Jiang, L., Zhao, M., Planavsky, N., Wang, X., Liu, W., 2019. Authigenic origin for a massive negative carbon isotope excursion. Geology 47, 115-118. Neoproterozoic contains several pronounced negative carbon isotope excursions that have been the topic of intense debate. The foremost of these, the “Shuram excursion,” represents the largest known carbon isotope excursion in Earth’s history. These negative carbon isotope excursions have been variably interpreted to record primary seawater values and massive carbon cycle perturbations, diagenetic alteration, or porewater authigenic carbonate formation. Although there are abundant examples of recent and Phanerozoic authigenic carbonates with markedly negative carbonate carbon isotope values, these carbonates are clearly identifiable as diagenetic products, making it difficult to link them to Neoproterozoic carbon isotope excursions. Here, we report the occurrence of a Middle Triassic, shallow-marine and lagoonal succession that contains a negative carbon isotope excursion in fine crystalline and peloidal carbonates that is comparable—in terms of its magnitude and stratigraphic structure and variability—to several Neoproterozoic carbon isotope excursions. A coupled petrographic and multiple isotope (C-O-Sr-U) approach suggests that the excursion was driven by carbonate precipitation within anoxic porewaters. Extensive carbon precipitation in the upper portion of the sediment pile was likely linked to inhibited bioturbation and a high background carbonate saturation state in an evaporative setting. The discovery of a Phanerozoic authigenic carbon isotope excursion bolsters the case that some stratigraphically continuous Neoproterozoic negative carbon isotope excursions may be tied to carbonate formation within the sediment pile.Jiang, S., Chen, X., Bernaola, G., 2019. Environmental controls on calcareous nannoplankton response to the Cretaceous/Paleogene mass extinction in the Tethys realm. Palaeogeography, Palaeoclimatology, Palaeoecology 515, 134-142. Cretaceous/Paleogene (K/Pg) mass extinction exhibits a remarkable geographical contrast between the Northern and Southern Hemispheres in extinction severity and recovery response, yet environmental facets of this extinction selectivity are still poorly known. Here, we statistically analyze the calcareous nannofossil counts from six K/Pg boundary sections from the Tethys Ocean, representing a northern subtropical depth transect from continental shelf to abyssal plain. Our analyses reveal that calcareous nannoplankton from all environments underwent an ecological crisis and responded similarly to the K/Pg environmental catastrophe, providing a solid basis for paleoecological reconstruction with nannofossils across the world oceans. Most interesting is the environment-dependent response pattern, as demonstrated by the increasing separation between shelf and deep ocean sites that signals a deepened environmental stress gradient. This environment-dependent response can be attributed to the marked difference in primary production and community composition between shelf and pelagic ecosystems, as well as the smaller accommodation and buffering capacity of shelves, while the progressive removal of susceptible species with increasing water depth seems to be of little influence.Jiang, T., Jin, Z., Liu, G., Liu, Q., Gao, B., Liu, Z., Nie, H., Zhao, J., Wang, R., Zhu, T., Yang, T., 2019. Source analysis of siliceous minerals and uranium in Early Cambrian shales, South China: Significance for shale gas exploration. Marine and Petroleum Geology 102, 101-108. shale gas exploration in the Early Cambrian shales of southern China requires the identification of favorable target areas. This study used logs for U, Si, Al, and total organic carbon (TOC) from three typical wells to assess a new framework for gas exploration in this area. The excess siliceous mineral content (from a non-terrigenous clastic source) ranged from 20 to 30% in most layers, reaching 50%. Analysis of these excess siliceous minerals using an Al-Fe-Mn ternary plot showed that most were probably derived from hydrothermal fluids within the boundary of the Yangtze and Cathaysian plates. Excess siliceous mineral content and uranium content had a good positive correlation, both tending to decrease away from the plate boundary, indicating that both were derived from hydrothermal fluids. Radioactive uranium in hydrothermal fluids can enhance biological productivity, which is conducive to the increased accumulation of sedimentary organic matter. Therefore, shale gas exploration in the Early Cambrian layers of South China should focus on target areas near the plate boundary that have increased uranium levels, moderate maturity, and good preservation conditions.Jiang, W., Wu, H., Li, Q., Lin, Y., Yu, Y., 2019. Spatiotemporal changes in C4 plant abundance in China since the Last Glacial Maximum and their driving factors. Palaeogeography, Palaeoclimatology, Palaeoecology 518, 10-21. of changes in the distribution of C3 and C4 plants in relation to climate change is the key to predicting the biosphere's response to future climatic warming. There are significant differences in the spatiotemporal evolution of C4 plant abundance at different latitudes since the Last Glacial Maximum (LGM), and the factors responsible remain debated. In this study, we reconstructed the spatiotemporal pattern of C4 plants in China since the LGM, based on a synthesis of δ13C records of soil organic matter from paleosol sequences and δ13C records of individual n-alkanes from lake and marine sediments. The results indicate that, spatially, maximum C4 abundance during the LGM was in South China; while maximum C4 abundance occurred in the Chinese Loess Plateau in North China during the early and mid-Holocene. Temporally, in North China, C4 plant abundance initially increased since the LGM, reached a maximum during the early and mid-Holocene and then decreased; however, the opposite trend occurred in South China. Combined with a physiological-process model used to study the sensitivity of C3 and C4 plants to changes in climate and atmospheric pCO2 in different regions, our results reveal that temperature was the dominant factor driving C4 plant expansion in North China, whereas atmospheric pCO2 and precipitation were the main factors controlling C4 plant abundance in South China.Jiang, Z.-R., Zuo, Y.-H., Yang, M.-H., Zhang, Y.-X., Zhou, Y.-S., 2018. Source rocks evaluation of the Paleogene Shahejie 3 Formation in the Dongpu Depression, Bohai Bay Basin. Energy Exploration & Exploitation 37, 394-411. simulation results based on two-dimensional basin cannot obtain accurate evaluations of petroleum resources because of not combining the thermal history in the Dongpu Depression. In this paper, Shahejie 3 Formation source rocks are evaluated using the geochemical data, and based on the thermal history, the thermal maturity evolution of typical wells and the top and bottom of the Shahejie 3 Formation source rocks are modeled using BasinMod software. Results show that source rocks are mainly distributed in the Haitongji-Liutun and Qianliyuan areas, and dominated by medium to high maturity source rocks. Organic matter types are primarily types II and III kerogen with a small amount of type I. The Shahejie 3 Formation source rocks in the Menggangji area experienced two stages of hydrocarbon generation: (1) during the Dongying Formation depositional period (33?17?Ma) and (2) from the Minghuazhen Formation depositional period to present (5.1?0?Ma). The source rocks are generally underdeveloped with low potential for hydrocarbon generation due to nonpoor and thin source rocks in this area. The two stages of hydrocarbon generation are not obvious for other areas. When the bottom of the source rocks reached overmature stage, the mid-lower Shahejie 3 Formation experienced the peak of hydrocarbon generation during the Dongying Formation depositional period. The thermal maturity evolution of the Shahejie 3 Formation source rocks revealed that the main hydrocarbon generation period was during the Dongying Formation depositional period. Therefore, petroleum exploration is suggested to be performed at the Shahejie 3 Formation source rocks in the Qianliyuan and Haitongji-Liutun areas to study the lithology and discover complex petroleum reservoirs in the Dongpu Depression.Joesten, W.C., Kennedy, M.A., 2019. RANCM: a new ranking scheme for assigning confidence levels to metabolite assignments in NMR-based metabolomics studies. Metabolomics 15, 5.: The Metabolomics Standards Initiative has recommended four categories for metabolite assignments in NMR-based metabolic profiling studies. The “putatively annotated compound” category is most commonly reported by metabolomics investigators. However, there is significant ambiguity in reliability of “putatively annotated compound” assignments, which can range from low confidence made on minimal corroborating data to high confidence made on substantial corroborating data.Objectives: To introduce a new ranking system, Rank and AssigN Confidence to Metabolites (RANCM), to assign confidence levels to “putatively annotated compound” assignments in NMR-based metabolic profiling studies.Methods: The ranking system was constructed with three confidence levels ranging from Rank 1 for the lowest confidence assignment level to Rank 3 for the highest confidence assignment level. A decision tree was constructed to guide rank selection for each metabolite assignment.Results: Examples are provided from experimental data demonstrating how to use the decision tree to make confidence level assignments to “putatively annotated compounds” in each of the three rank levels. A standard Excel sheet template is provided to facilitate decision-making, documentation and submission to data repositories.Conclusion: RANCM is intended to reduce the ambiguity in “putatively annotated compound” assignments, to facilitate effective communication of the degree of confidence in “putatively annotated compound” assignments, and to make it easier for non-experts to evaluate the significance and reliability of NMR-based metabonomics studies. The system is straightforward to implement, based on the most common datasets collected in NMR-based metabolic profiling studies, and can be used with equal rigor and significance with any set of NMR datasets.Johnson, P.V., Hodyss, R., Vu, T.H., Choukroun, M., 2019. Insights into Europa's ocean composition derived from its surface expression. Icarus 321, 857-865. global ocean believed to exist beneath Europa's thick ice shell is often cited as one of the most likely places in the solar system to find evidence of extraterrestrial habitable environments or even extant life. However, given the technical challenges and the costs associated with outer solar system exploration, direct analysis of the ocean appears unlikely in the foreseeable future. Therefore, constraints on the chemical composition of the ocean will need to be inferred, for example, from analysis of the surface ice, either via remote sensing or landed surface missions. In this paper, we combine our recent body of work studying the chemistry of frozen putative Europa ocean brines with new experiments to develop predictions of the sequence by which the hydrated minerals form when a four-ionic component ocean (Na+, Cl?, Mg2+, and SO42?) freezes as a function of relative ionic concentrations and pH. This in turn provides a means to begin linking observed surface chemistry and the chemical environment of the subsurface ocean as well as insight into endogenic versus exogenic origin of detected species.Kabanov, P., 2019. Devonian (c. 388–375?Ma) Horn River Group of Mackenzie Platform (NW Canada) is an open-shelf succession recording oceanic anoxic events. Journal of the Geological Society 176, 29. least four horizons of enhanced anoxia (anoxic horizons; AHs) are recognized in the uppermost Eifelian–Middle Frasnian mudrock-dominated strata of the Mackenzie Valley and Peel area of NW Canada. Aluminium-normalized Mo and U logs in two cored sections reveal AH-I at the Eifelian–Givetian boundary, AH-II in basal Frasnian, and AH-III and AH-IV bundled in the Middle Frasnian interval. These four horizons are characterized by attenuated siliciclastic components. Spectral gamma-ray K?+?Th and U are the best tools to trace these horizons in wells and outcrops. AHs are biostratigraphically correlated with ‘black-shale events’ in several basins of the world. Depositional environment is depicted as a stratified basin where the water-column chemocline defined co-sedimentation of anoxic mudrocks in topographic lows and oxic grey shales and carbonate banks on seafloor elevations. Based on inductively coupled plasma elemental data from 1687 samples, siliciclastic-lean basinal mudrock units that host AHs are strongly enriched in Mo (median EFMo?～?97–172?EFMo/EFU?≈?(3–3.5)?×?SW, where EFMo and EFU are respectively Al-normalized Mo and U in enrichment factor notation and SW is average present-day seawater value) compared with siliciclastic-rich units (median EFMo?～?17–37) and show strong EFU/EFMo covariation (r?≈?0.8 in Canol Formation and Bluefish Member). Supported by a lack of geological evidence for an oceanographic barrier, this enrichment indicates unrestricted water exchange with Panthalassa. At the same time, development of oligotrophy is indicated by a lack of P enrichment and weak to non-existent enrichment in Zn and Cu. These features are reconciled through a model by earlier workers that involves a global shift to a warm greenhouse mode with slowed oceanic convection, expanded oxygen minimum zones and a failure of nutrient resupply from the upwelling. The onset of mass degassing in continental large igneous provinces represents a potential trigger for this mid-Devonian shift. Devonian black-shale events in this scenario represent genuine oceanic anoxic events marking hothouse episodes in their nascent form.Supplementary material: Details of methods, analytical protocols and data scatterplots, stratigraphic cross-sections showing traceability of anoxic horizons, and inductively coupled plasma elemental and Rock-Eval 6 data used in this study are available at: , D., Liang, J., Kuang, Z., Lu, J.a., Guo, Y., Liang, J., Cai, H., Qu, C., 2018. Application of elemental capture spectroscopy logging in hydrate reservoir evaluation in the Shenhu sea area. Natural Gas Industry B 38, 54-60. the hydrate drilling process of Well W18 during GBGS-3 sequence of voyages in the Shenhu sea area, the northern South China Sea, the logging while drilling (LWD) shows that the gamma values of upper hydrate reservoirs and the intervals above them are obviously low. According to the core testing results, however, the quartz content of low-gamma intervals doesn't increase significantly. And the carbonate content and lithologic features of formation rocks cannot be figured out by virtue of conventional logging methods, so no correct interpretation can be provided. In this paper, the principle of elementary capture spectroscopy（ECS）logging was analyzed. Then, the mineral component determined based on the ECS logging data of Well W18 was taken as the input of ElanPlus logging processing, and combined with other conventional logging data, the mineral component of related strata was identified accurately, and accordingly the lithologic section of Well W18 was determined. Finally, the hydrate porosity, hydrate saturation and matrix permeability in Well W18 were calculated by two methods, i.e., the density log and the ECS logging process which takes the mineral component content as the response parameter. And the following research results were obtained. First, the low-gamma intervals in Well W18 are generated by the increase of calcite content instead of sandy components. Second, the hydrate porosity acquired by these two methods is generally consistent, but the result by the latter method fits better with the core analysis results. In conclusion, the ECS logging provides a new technique and method for the comprehensive evaluation of hydrate reservoirs and improves the coincidence rates of the logging interpretation of hydrate reservoirs.Kartavenka, K., Panuwet, P., Greenwald, R., Ehret, K.M., D'Souza, P.E., Barr, D.B., Ryan, P.B., 2019. Quantification of malondialdehyde in exhaled breath condensate using pseudo two-dimensional ultra-performance liquid chromatography coupled with single quadrupole mass spectrometry. Journal of Chromatography B 1105, 210-216. developed a robust analytical method for quantification of malondialdehyde (MDA) in exhaled breath condensate (EBC) via derivatization with 2,4-dinitrophenylhydrazine (DNPH). The target MDA-DNPH hydrazone was separated by ultra-performance liquid chromatography using two reversed-phase analytical columns (C18 and phenyl-hexyl) inter-connected via a two-position, six-port switching valve to a single-quadrupole mass spectrometer. The target derivative was analyzed under positive electrospray ionization using single ion monitoring mode (m/z?=?235 for the target derivative, and m/z?=?237 for its labeled isotopic analog). This pseudo two-dimensional chromatographic separation provided optimum separation conditions for the target derivative resulting in the limit of detection of 0.58?nM in EBC sample (or 36.2?pmol on-column amount), which is comparable to those reported previously using different techniques, including tandem mass spectrometry. Based on the calibration solutions, the method had a linear quantification range of 1.0–200?nM (r2?=?0.998). The method showed good relative recoveries (92.2–102.0%) and acceptable precisions (3.6–12.2% for inter-day precision, and 4.3–12.4% for intra-day precision for two quality control levels, prepared from 5?nM and 25?nM solutions). The derivative was found to be stable at room temperature for 48?h or during analysis. The method was used to analyze 205 exhaled breath condensate samples collected from individuals from a healthy population of student athletes. MDA was detected in approximately 95% of these samples, with concentrations ranging from 1.16 to 149.63?nM. The median concentration was 6.82?nM, (IQR 4.08–9.88). These data demonstrate that our method can be successfully used to measure MDA in population studies.Kaur, U., Johnson, D.T., Chea, E.E., Deredge, D.J., Espino, J.A., Jones, L.M., 2019. Evolution of structural biology through the lens of mass spectrometry. Analytical Chemistry 90, 142-155. its inception in the early 20th century, mass spectrometry (MS) has become a significant method to analyze molecules. In the century since JJ Thomson’s first use of MS in 1913, the application of this analytical technique has expanded to a wide variety of industries including pharmaceutics, biotechnology, forensics, and environmental. Advancements in instrumentation have allowed for diversity in the type of molecules that can be analyzed by MS. The development of electrospray ionization (ESI) and matrix-assisted laser desorption ionization (MALDI) in the 1980s has increased the size of molecules that can be studied, allowing for the analysis of proteins to be well in the scope of the technique and has increased the range of MS to biological applications. Although mass spectrometry has been used for many years to analyze proteins, mainly for protein sequencing, it is only through developments within roughly the last two decades that have enabled it to be used as a technique for studying protein structure.Kayukova, G.P., Mikhailova, A.N., Khasanova, N.M., Morozov, V.P., Vakhin, A.V., Nazimov, N.A., Sotnikov, O.S., Khisamov, R.S., 2018. Influence of hydrothermal and pyrolysis processes on the transformation of organic matter of dense low-permeability rocks from Domanic Formations of the Romashkino oil field. Geofluids 2018, Article 9730642. model experiments regarding the conversion of organic matters from carbonate rock samples of Dankov-Lebedyan deposits of Zelenogorskaya area and siliceous-carbonate rocks of Semiluki-Mendym deposits of Berezovskaya area of Domanic formations of Romashkino oil field were carried out. Two types of experiments were carried out: (1) the hydrothermal treatment of rocks at a temperature of 350°C in the presence of carbonic acid and a water content of 30%; (2) pyrolysis at temperatures of 350 and 600°C in the presence of hydrogen. The yield and quality of extracted hydrocarbons from the rocks depending on the mineral composition of rocks, content and composition of organic matter, and thermal stability of kerogen under hydrothermal influences were evaluated. Application of electron paramagnetic resonance in pyrolysis processes revealed the difference in mineral content of rocks (Mn2+, SO3?, and SO2? ions) and free radicals R, as well as in vanadyl ion (VO2+) concentration. It is established that an increasing temperature of pyrolysis promotes the formation of new free organic radicals in rock samples: in Domanic rocks of Semiluki-Mendym deposits at 350°С and in carbonate rocks of Dankov-Lebedyan horizon at 600°С. This indicates different ability of oil-generating potential of rocks with hydrothermal and pyrolysis technologies.Kebukawa, Y., Kobayashi, H., Urayama, N., Baden, N., Kondo, M., Zolensky, M.E., Kobayashi, K., 2019. Nanoscale infrared imaging analysis of carbonaceous chondrites to understand organic-mineral interactions during aqueous alteration. Proceedings of the National Academy of Sciences 116, 753-758.: Spatial relationships between organic matter and minerals are necessary for understanding the formation and evolution of organic matter during aqueous and thermal alteration in their parent bodies, as well as preaccretional history. Infrared spectroscopy is a powerful tool to analyze the molecular structures of organic matter and identification of minerals. However, its spatial resolution is limited due to the diffraction limit. Recently, the atomic force microscopy (AFM) based IR nanospectroscopy was developed and applied in various scientific fields to overcome the diffraction limit of IR. We applied the AFM-based IR nanospectroscopy to carbonaceous chondrites and studied organic-mineral associations at the ～30 nm spatial resolution.Abstract: Organic matter in carbonaceous chondrites is distributed in fine-grained matrix. To understand pre- and postaccretion history of organic matter and its association with surrounding minerals, microscopic techniques are mandatory. Infrared (IR) spectroscopy is a useful technique, but the spatial resolution of IR is limited to a few micrometers, due to the diffraction limit. In this study, we applied the high spatial resolution IR imaging method to CM2 carbonaceous chondrites Murchison and Bells, which is based on an atomic force microscopy (AFM) with its tip detecting thermal expansion of a sample resulting from absorption of infrared radiation. We confirmed that this technique permits ～30 nm spatial resolution organic analysis for the meteorite samples. The IR imaging results are consistent with the previously reported association of organic matter and phyllosilicates, but our results are at much higher spatial resolution. This observation of heterogeneous distributions of the functional groups of organic matter revealed its association with minerals at ～30 nm spatial resolution in meteorite samples by IR spectroscopy.K?dzior, S., 2019. Distribution of methane contents and coal rank in the profiles of deep boreholes in the Upper Silesian Coal Basin, Poland. International Journal of Coal Geology 202, 190-208. central, western and southwestern parts of the Polish Upper Silesian Coal Basin (USCB) are characterized by elevated methane contents and coal ranging in rank from high-volatile bituminous to anthracite. Two patterns of methane distribution with depth have been recognized. The northern pattern involves a naturally outgassed zone and a primary methane interval below 600–800?m. The southern pattern comprises a secondary peak immediately below Miocene cover rocks and a deeper primary peak. A variety of factors influencing present-day methane contents make the distribution of methane at depth complex even in individual boreholes. An analysis of the depth trend of average methane contents reveals that, in some cases, the primary methane peak is divided into two smaller sub-peaks, the first coinciding with medium-volatile bituminous coal and the second typically with the transition from low-volatile bituminous coal to anthracite. The sub-maxima are separated by an interval of gradually decreasing methane content, usually in the direction towards low-volatile bituminous coals. Rapid increases in methane content with depth are probably related to the occurrence of medium-volatile bituminous coals that are, in turn, related to the second coalification jump at which coal loses ca. 10% of its volatiles, producing, inter alia, methane which is adsorbed by the coal. Low-volatile bituminous coal and anthracite are characterized by high methane contents due to further methane generation at this stage of the coalification process. Anthracite has a high methane content because of its high sorption capacity and high coal rank. Though basin evolution, temperature, and pressure (stress) are the key factors influencing the process of methane generation, coal sorption capacity for gases and present-day depth distribution of methane, other processes of gas migration and accumulation contribute to distribution patterns that are both variable and complex.Keenan, S.W., Schaeffer, S.M., DeBruyn, J.M., 2019. Spatial changes in soil stable isotopic composition in response to carrion decomposition. Biogeosciences Discussions 2019, 1-35. provides a critical mechanism for returning nutrients to the surrounding environment. In terrestrial systems, animal carcass, or carrion, decomposition results in a cascade of biogeochemical changes. Soil microbial communities are stimulated, resulting in transformations of carbon (C) and nitrogen (N) sourced from the decaying carrion soft tissues, changes to soil pH and electrical conductivity as microbial communities release CO2 and mineralize organic N, and significant changes to oxygen availability. Over time, microbial communities transform ammonium to nitrate and potentially N2O through nitrification and denitrification. While many of the rapid changes to soil biogeochemistry observed during carrion decomposition return to background or starting conditions shortly after soft tissues are degraded, some biogeochemical parameters, particularly bulk soil stable δ15N isotopic composition, have the potential to exhibit prolonged perturbations, extending for several years. The goal of this study was to evaluate the lateral and vertical changes to soil stable isotopic composition one year after carrion decomposition in a forest ecosystem. Lateral transects extending 140cm from three decomposition hotspots were sampled at 20cm intervals, and subsurface cores were collected beneath each hotspot to a depth of 50cm. Bulk soil stable isotopic composition (δ15N and δ13C) indicated that one year after complete soft tissue removal and decay, soils were significantly 15N-enriched compared to control soils up to 60cm from the hotspot center, and enrichment extended to a depth of 10cm. Our results demonstrate that carrion decomposition has the potential to result in long-term changes to soil biogeochemistry, up to at least one year after soft tissue degradation, and to contribute to bulk soil stable isotopic composition.Keller, C.B., Husson, J.M., Mitchell, R.N., Bottke, W.F., Gernon, T.M., Boehnke, P., Bell, E.A., Swanson-Hysell, N.L., Peters, S.E., 2019. Neoproterozoic glacial origin of the Great Unconformity. Proceedings of the National Academy of Sciences 116, 1136-1145.: It has long been observed that the sequence of sedimentary rocks deposited in the past half-billion years often sharply overlies older igneous or metamorphic basement at an erosional surface known as the Great Unconformity. We provide evidence that this unconformity may record rapid erosion during Neoproterozoic “snowball Earth” glaciations. We show that the extent of Phanerozoic sedimentation in shallow continental seas can be accurately reproduced by modeling the accommodation space produced by the proposed glacial erosion, underlining the importance of glaciation as a means for lowering erosional base level. These results provide constraints on the sedimentary and geochemical environment in which the first multicellular animals evolved and diversified in the “Cambrian explosion” following the unconformity.Abstract: The Great Unconformity, a profound gap in Earth’s stratigraphic record often evident below the base of the Cambrian system, has remained among the most enigmatic field observations in Earth science for over a century. While long associated directly or indirectly with the occurrence of the earliest complex animal fossils, a conclusive explanation for the formation and global extent of the Great Unconformity has remained elusive. Here we show that the Great Unconformity is associated with a set of large global oxygen and hafnium isotope excursions in magmatic zircon that suggest a late Neoproterozoic crustal erosion and sediment subduction event of unprecedented scale. These excursions, the Great Unconformity, preservational irregularities in the terrestrial bolide impact record, and the first-order pattern of Phanerozoic sedimentation can together be explained by spatially heterogeneous Neoproterozoic glacial erosion totaling a global average of 3–5 vertical kilometers, along with the subsequent thermal and isostatic consequences of this erosion for global continental freeboard.Keshavarz, V., Khosravanian, R., Taheri-Shakib, J., Salimidelshad, Y., Hosseini, S.A., 2019. Chemical removal of organic precipitates deposition from porous media: Characterizing adsorption and surface properties. Journal of Petroleum Science and Engineering 175, 200-214. destructive effects of oil-based mud (OBM) on the laboratory and operating conditions are substantial. The result of this damage leads to a drop in oil production by reducing porosity and absolute and relative permeability. In the drilling process, the oil-wetting behavior of the wellbore brings about a lack of proper bonding between cement and the borehole. In the laboratory, these impairments also cause errors in the RCAL and SCAL test results. In this study, calcite samples aged with oil-base drilling mud were washed with various chemical solvents to remove damage induced on the surface properties of the rock. Then, experiments such as FTIR, Zeta, SEM, EDS, and contact angle measurements were performed and these tests indicate the cleaning ability of each solvent on each sample. The results of the FTIR test showed that TL?+?M, DCM?+?E, CF?+?E, THF?+?M, THF?+?E solvents had the greatest efficiency in eliminating both polar and nonpolar compounds. The zeta potential test showed that the two solvents DCM?+?E, TL?+?M removed more negative charges from the rock surface than other solvents. In SEM imaging, the solvents TL?+?M, THF?+?M, THF?+?P and DCM?+?E provided better cleaning of the rock surface. Also, the EDS test introduces THF?+?M, DCM, DCM?+?E, TL?+?M solvents as a strong solvent in removing deposits from the OBM. Regarding the contact angle test, the solvents DCM?+?E and TL?+?M obtained the highest reduction in the contact angle of the oil drop on the rock surface. All experiments showed that polar and nonpolar compounds should be eliminated in order to restore physical (solid components of the mud) and chemical (wettability alteration) damage. This is accomplished by pure solvents with polar and nonpolar abilities such as dichloromethane. The use of polar/non-polar combination solvents can also be very effective, provided that these two solvents do not form stable bonds with each other.Khlystov, O.M., Poort, J., Mazzini, A., Akhmanov, G.G., Minami, H., Hachikubo, A., Khabuev, A.V., Kazakov, A.V., De Batist, M., Naudts, L., Chensky, A.G., Vorobeva, S.S., 2019. Shallow-rooted mud volcanism in Lake Baikal. Marine and Petroleum Geology 102, 580-589. Baikal is the only freshwater basin containing sediments with gas hydrate accumulations, some of which are associated with mud volcano activity. Twenty-two mud volcanoes have already been identified in different areas of Lake Baikal, but the formation process and source depth remained unknown due to a lack of conclusive evidences. Here we discuss a set of geological and geophysical data to report the discovery of the hydrate-bearing Akadem mud volcanic complex (AMVC) on the Academician Ridge in central Lake Baikal. The obtained results allowed for the first time to concretely estimate the source depth of the mobilized fluids and sediments. Analysis of diatom skeletons present in the mud breccia revealed that the oldest diatom specimen is Cyclotella Iris et var. This species is characteristic for a short age interval ranging between 4.8 and 5.6?Ma. The same diatom was also detected between 230 and 310?m below the lake floor (mblf) in the borehole BDP-98 drilled near the AMVC. Combining biostratigraphic correlation and seismostratigraphy, it is estimated that the same interval is located at 200–300 mblf below the mud volcanic field. The elevated heat flow measured at AMVC indicates that the original base of gas hydrate stability (regionally located at ～212 mblf) is currently shifted upwards of ～100?m. The acquired data are consistent with a scenario envisaging the rise of warm fluids throughout the mud volcano complex zone. We suggest that migration of deep fluids could have initiated the gas hydrate dissociation and, in turn, rapidly generated overpressured shallow mud chambers. The ultimate piercing and triggering of the mud volcanoes activity resulted in the eruption of mud breccia and formation of densely packed crater sites in the study area. The depicted scenario can be applied to many mud volcanoes in Lake Baikal where similar anomalous heat flow conditions have been measured. These findings also emphasize that the genetic association between gas hydrate dissociation and the initiation of eruptive activity explains numerous peculiarities of the “Baikal” sedimentary volcanism (e.g. lack of lithified rocks among mud breccia clasts, gas hydrates, moderately elevated heat flow). This type of mud volcanism differentiates from the typically deeply rooted piercements observed worldwide in mature (marine) sedimentary basins. Ultimately our findings open a new prospective for mud volcano research worldwide, emphasizing that gas hydrates are not just one of the common features for sedimentary volcanism, but may have an active role as a triggering mechanism for the process itself.Kimmig, J., Meyer, R.C., Lieberman, B.S., 2019. Herpetogaster from the early Cambrian of Nevada (Series 2, Stage 4) and its implications for the evolution of deuterostomes. Geological Magazine 156, 172-178. Pioche Formation of SE Nevada preserves a diverse soft-bodied fauna from the early and middle Cambrian (Series 2–3: Stage 4–5). While the fauna is dominated by arthropods, animals belonging to other taxa can be found. Here we document the first occurrence of Herpetogaster collinsi outside the Burgess Shale. Further, the specimens are from the Nephrolenellus multinodus biozone and thus represent the oldest occurrence of the species, as well as possibly the earliest soft-bodied deuterostomes in Laurentia.King, A.C.F., Giorio, C., Wolff, E., Thomas, E., Karroca, O., Roverso, M., Schwikowski, M., Tapparo, A., Gambaro, A., Kalberer, M., 2019. A new method for the determination of primary and secondary terrestrial and marine biomarkers in ice cores using liquid chromatography high-resolution mass spectrometry. Talanta 194, 233-242. majority of atmospheric compounds measured in ice cores are inorganic, while analysis of their organic counterparts is a less well developed field. In recent years, understanding of formation, transport pathways and preservation of these compounds in ice and snow has improved, showing great potential for their use as biomarkers in ice cores. This study presents an optimised analytical technique for quantification of terrestrial and marine biosphere emissions of secondary organic aerosol (SOA) components and fatty acids in ice using HPLC-MS analysis. Concentrations of organic compounds in snow and ice are extremely low (typically ppb or ppt levels) and thus pre-concentration is required prior to analysis. Stir bar sorptive extraction (SBSE) showed potential for fatty acid compounds, but failed to recover SOA compounds. Solid phase extraction (SPE) recovered compounds across both organic groups but methods improving some recoveries came at the expense of others, and background contamination of fatty acids was high. Rotary evaporation was by far the best performing method across both SOA and fatty acid compounds, with average recoveries of 80%. The optimised preconcentration – HPLC-MS method achieved repeatability of 9% averaged for all compounds. In environmental samples, both concentrations and seasonal trends were observed to be reproducible when analysed in two different laboratories using the same method.Kirse, C., Kindlein, M., Luxenburger, F., Elts, E., Briesen, H., 2019. Analysis of two common algorithms to compute self-diffusion coefficients in infinite dilution from molecular dynamics simulations and application to n-alkanes (C1 to C35) in water. Fluid Phase Equilibria 485, 211-219. this study the order-n algorithm and the linear regression algorithm used to obtain self-diffusion coefficients from molecular dynamics simulations are compared using theoretical analysis and Monte Carlo simulations. This analysis shows that the order-n algorithm allows decreasing the uncertainty in self-diffusion coefficients without increased computational effort. Both algorithms are used to calculate self-diffusion coefficients of linear n-alkanes in infinite dilution in water. Using the same trajectories the results obtained by the order-n algorithm had an average deviation from the experimental value of 2%, whereas using the linear regression algorithm the deviation was 12.5%. A guideline for selecting an optimal frequency, in which the center of mass trajectories from the molecular dynamics simulations should be written out, is given for the order-n algorithm.Kitzinger, K., Padilla, C.C., Marchant, H.K., Hach, P.F., Herbold, C.W., Kidane, A.T., K?nneke, M., Littmann, S., Mooshammer, M., Niggemann, J., Petrov, S., Richter, A., Stewart, F.J., Wagner, M., Kuypers, M.M.M., Bristow, L.A., 2019. Cyanate and urea are substrates for nitrification by Thaumarchaeota in the marine environment. Nature Microbiology 4, 234-243. archaea of the phylum Thaumarchaeota are among the most abundant marine microorganisms1. These organisms thrive in the oceans despite ammonium being present at low nanomolar concentrations2,3. Some Thaumarchaeota isolates have been shown to utilize urea and cyanate as energy and N sources through intracellular conversion to ammonium4–6. Yet, it is unclear whether patterns observed in culture extend to marine Thaumarchaeota, and whether Thaumarchaeota in the ocean directly utilize urea and cyanate or rely on co-occurring microorganisms to break these substrates down to ammonium. Urea utilization has been reported for marine ammonia-oxidizing communities7–10, but no evidence of cyanate utilization exists for marine ammonia oxidizers. Here, we demonstrate that in the Gulf of Mexico, Thaumarchaeota use urea and cyanate both directly and indirectly as energy and N sources. We observed substantial and linear rates of nitrite production from urea and cyanate additions, which often persisted even when ammonium was added to micromolar concentrations. Furthermore, single-cell analysis revealed that the Thaumarchaeota incorporated ammonium-, urea- and cyanate-derived N at significantly higher rates than most other microorganisms. Yet, no cyanases were detected in thaumarchaeal genomic data from the Gulf of Mexico. Therefore, we tested cyanate utilization in Nitrosopumilus maritimus, which also lacks a canonical cyanase, and showed that cyanate was oxidized to nitrite. Our findings demonstrate that marine Thaumarchaeota can use urea and cyanate as both an energy and N source. On the basis of these results, we hypothesize that urea and cyanate are substrates for ammonia-oxidizing Thaumarchaeota throughout the ocean.Kluender, E.J., Hedrick, J.L., Brown, K.A., Rao, R., Meckes, B., Du, J.S., Moreau, L.M., Maruyama, B., Mirkin, C.A., 2018. Catalyst discovery through megalibraries of nanomaterials. Proceedings of the National Academy of Sciences 115, 13330-13335.: Discovering new materials is traditionally a slow process, as the materials genome encompasses a massive parameter space, particularly on the nanoscale where synthesis methods are less universal. To overcome this challenge, a cantilever-free lithography method has been used to deposit millions of discrete nanoreactors on a substrate, which can be transformed into millions of nanoparticles spatially encoded in terms of composition and size. These compositions were screened for their ability to catalytically grow carbon nanotubes, and a composition (Au3Cu) was identified as optimum for this application. More generally, this combinatorial method of synthesizing nanoparticle megalibraries offers researchers a platform for identifying structures with desired properties at a rate not previously possible.Abstract: The nanomaterial landscape is so vast that a high-throughput combinatorial approach is required to understand structure–function relationships. To address this challenge, an approach for the synthesis and screening of megalibraries of unique nanoscale features (>10,000,000) with tailorable location, size, and composition has been developed. Polymer pen lithography, a parallel lithographic technique, is combined with an ink spray-coating method to create pen arrays, where each pen has a different but deliberately chosen quantity and composition of ink. With this technique, gradients of Au-Cu bimetallic nanoparticles have been synthesized and then screened for activity by in situ Raman spectroscopy with respect to single-walled carbon nanotube (SWNT) growth. Au3Cu, a composition not previously known to catalyze SWNT growth, has been identified as the most active composition.Kocken, I.J., Cramwinckel, M.J., Zeebe, R.E., Middelburg, J.J., Sluijs, A., 2019. The 405 kyr and 2.4 Myr eccentricity components in Cenozoic carbon isotope records. Climate of the Past 15, 91-104. stable carbon (δ13C) and oxygen (δ18O) isotope ratios of deep-sea foraminiferal calcite co-vary with the 405?kyr eccentricity cycle, suggesting a link between orbital forcing, the climate system, and the carbon cycle. Variations in δ18O are partly forced by ice-volume changes that have mostly occurred since the Oligocene. The cyclic δ13C–δ18O co-variation is found in both ice-free and glaciated climate states, however. Consequently, there should be a mechanism that forces the δ13C cycles independently of ice dynamics. In search of this mechanism, we simulate the response of several key components of the carbon cycle to orbital forcing in the Long-term Ocean-atmosphere-Sediment CArbon cycle Reservoir model (LOSCAR). We force the model by changing the burial of organic carbon in the ocean with various astronomical solutions and noise and study the response of the main carbon cycle tracers. Consistent with previous work, the simulations reveal that low-frequency oscillations in the forcing are preferentially amplified relative to higher frequencies. However, while oceanic δ13C mainly varies with a 405?kyr period in the model, the dynamics of dissolved inorganic carbon in the oceans and of atmospheric CO2 are dominated by the 2.4?Myr cycle of eccentricity. This implies that the total ocean and atmosphere carbon inventory is strongly influenced by carbon cycle variability that exceeds the timescale of the 405?kyr period (such as silicate weathering). To test the applicability of the model results, we assemble a long (～22?Myr) δ13C and δ18O composite record spanning the Eocene to Miocene (34–12?Ma) and perform spectral analysis to assess the presence of the 2.4?Myr cycle. We find that, while the 2.4?Myr cycle appears to be overshadowed by long-term changes in the composite record, it is present as an amplitude modulator of the 405 and 100?kyr eccentricity cycles.Koeberl, C., 2019. When Earth got pummeled. Science 363, 224-225. and impact processes have been important throughout the history of the solar system, including that of Earth. Small bodies in the early solar system, the planetesimals, grew through collisions, ultimately forming the planets. Recognizing the remnants of impact events on Earth is difficult because terrestrial processes either cover or erase the surface expression of impact structures in geologically short timespans. Because Earth and the Moon are subjected to the same flux of impactors, the latter's crater record serves as a proxy for that of Earth. On page 253 of this issue, Mazrouei et al. (1) report that infrared images of the Moon taken by the Lunar Reconnaissance Orbiter Diviner instrument can be used to estimate the ages of young lunar craters. They find the impact rate increased within the last ～500 million years.Impact cratering is a high-energy event that occurs at more-or-less irregular intervals, although over long periods of time, an average cratering rate can be established (2). The terrestrial rock record, in the form of crustal rocks, extends back to only about 89% of Earth's history, to ～4.0 billion years ago, with the oldest rocks showing very limited exposures in Greenland and Canada. The importance of the process of impact cratering on a planetary scale has only recently been recognized in the geological sciences. During the past few decades, planetary scientists and astronomers have demonstrated, with the aid of many space missions, that the surfaces of Earth's moon, Mercury, Venus, Mars, the asteroids, and the moons of the outer gas planets are all covered (some surfaces to saturation) with meteorite impact craters.Part of the problem regarding recognition of the remnants of impact events on Earth is that terrestrial processes, such as sedimentation, erosion, and plate tectonics, either cover or erase the surface expression of impact structures. Many impact structures are covered by younger (post-impact) sediments and are not visible on the surface. Others were mostly destroyed by erosion. To determine if specific rocks have been subjected to impact or not, it is necessary to identify criteria that allow such processes to be distinguished from those resulting from normal terrestrial geological processes. Most of the geo logical features of meteorite impact structures are not unique. Such features can be the product of conventional processes such as tectonic deformation, salt-dome formation, volcanic eruption, or internal igneous activity. Only the presence of diagnostic shock metamorphic effects and, in some cases, the discovery of meteorites, or traces thereof, provide unambiguous evidence for an impact origin (3). As of 2018, about 190 impact structures have been identified on Earth on the basis of these criteria. With one exception, all of these are younger than 2 billion years.On some other planets and moons, the problem of geological processes destroying or obscuring the impact record is much less severe than on Earth. It has long been known that Earth's companion, the Moon, has been geologically mostly inactive on its surface for the past 3 billion years or so. This makes it an ideal canvas on which asteroids can leave their impact traces. Mazrouei et al. used Lunar Reconnaissance Orbiter data to derive the impact flux on the Moon for craters larger than about 10 km in diameter—and by proxy, also on Earth—during the past billion years. This was done by determining the ages of all lunar craters larger than 10 km using an inverse relationship between the absolute ages of craters and the “rockiness” of their ejecta, derived from the Lunar Reconnaissance Orbiter Diviner instrument. In previous studies, it was usually assumed that the paucity of craters on Earth is a direct result of the erosional and other geological forces that destroy or obscure such craters on Earth. Recently, an estimate of the number of impact craters that should be present at Earth's surface was reported (4). The study noted no evidence for any systematic incompleteness in the available inventory of the craters larger than about 6 km in diameter exposed at the surface but suggested that more than 90 craters with diameters ranging from 1 to 6 km have yet to be discovered, as well as more than 250 craters between 0.25 and 1 km in diameter. In the larger-size range (larger than a 6-km diameter), Mazrouei et al. now demonstrate that instead of an erosional bias for craters in the age range of about 650 to 290 million years ago, there is a lower-impact flux to be blamed, where the Snowball Earth ice ages (when Earth was entirely or nearly entirely frozen) might be responsible for erosion that destroyed any earlier craters. By contrast, a previous study suggested an increase in impact rate during the Phanerozoic period, 541 million years ago to the present (5).This still leaves a large part of Earth's history lacking for impact structures. The early record of impact on Earth is rather limited and mostly circumstantial. Likely impact debris layers (ejecta layers) have been documented in 3.2- to 3.47-billion-year-old Archean successions in the Barberton Greenstone Belt (South Africa) and Pilbara Craton (Australia). The exact number of ejecta layers is not known, but several different events between 3.4 and 2.5 billion years ago, and at 2.1 to 1.8 billion years ago, have been identified (6).The oldest impact structure on Earth dates to 2.02 billion years ago (Vredefort in South Africa), and for the “next” billions of years the impact record on Earth is quite sparse in terms of both craters and ejecta layers. Thus, Earth's impact record is quite limited: nothing for the first billion years, then some ejecta layers until about 2.5 billion years ago, and then less than a handful of impact craters prior to about 750 million years ago. Nevertheless, the discovery of these ejecta layers aids in the discussion of the importance of impact events in Earth's early history. So, despite having a good explanation for why a single time window in Earth's history might have seen as many impacts as originally anticipated, the earlier (pre–600 million years ago) impact record on Earth, which spans most of the age of the planet, is still a wide open field of research.References1. S. Mazrouei et al., Science 363, 253 (2019).2. E. M. Shoemaker et al.,in Global Catastrophes in Earth History, V. L. Sharpton, P. D. Ward, Eds. (Geological Society of America, Special Paper 247, 1990), pp. 155–170.3. B. M. French, C. Koeberl, Earth Sci. Rev. 98, 123 (2010).4. S. Hergarten, T. Kenkmann, Earth Planet. Sci. Lett. 425, 187 (2015).5. E. M. Shoemaker, in Meteorites: Flux with Time and Impact Effects, M. M. Grady, R. Hutchison, G. J. H. McCall, D. A. Rothery, Eds. (Geological Society of London, Special Publication 140, 1998), pp. 7–10..6. T. Schulz et al, Geochim. Cosmochim. Acta 211, 322 (2017).Komatsu, G., Orm?, J., Bayaraa, T., Arai, T., Nagao, K., Hidaka, Y., Shirai, N., Ebihara, M., Alwmark, C., Gereltsetseg, L., Tserendug, S., Goto, K., Matsui, T., Demberel, S., 2019. Further evidence for an impact origin of the Tsenkher structure in the Gobi-Altai, Mongolia: Geology of a 3.7 km crater with a well-preserved ejecta blanket. Geological Magazine 156, 1-24. Tsenkher structure in the Gobi-Altai, Mongolia is a c. 3.7 km diameter crater with a well-preserved ejecta blanket. It has been hypothesized to be either of impact or volcanic origin in our previous work. Observations during our 2007 expedition and related sample analyses give further support for an impact origin. The evidence includes the presence of a structurally uplifted near-circular rim surrounded by an ejecta blanket, and abundant breccias, some of which are melt- and millimetre-scale spherule-bearing. Planar deformation features (PDFs) were found in one quartz grain in a breccia sample. Fe-rich grains are found in a vesicular melt sample that is also characterized by elevated platinum group element (PGE) abundances with respect to the sedimentary bedrock of the area (approximately an order of magnitude). Noble gas analysis of one breccia sample yielded an elevated 3He/4He value of (5.0±0.2) × 10?6. Although not conclusive alone, these geochemical results are consistent with a contribution of meteoritic components. A volcanic origin, in particular a maar formation, would require explanations for the unusual conditions associated with Tsenkher, including its large size occurring in isolation, the structurally uplifted rim and the lack of a bedded base surge deposit. A pronounced rampart structure observed at the eastern ejecta is also unusual for any volcanic origin. 40Ar–39Ar dating of a vesicular melt sample gives an age of the Tsenkher structure of 4.9±0.9 Ma. The rampart structure could provide insights into the formation of similar ejecta morphologies associated with numerous impact craters on Mars.Kong, L., Ostadhassan, M., Hou, X., Mann, M., Li, C., 2019. Microstructure characteristics and fractal analysis of 3D-printed sandstone using micro-CT and SEM-EDS. Journal of Petroleum Science and Engineering 175, 1039-1048. sedimentary rocks using three-dimensional (3D) printing can support routine reservoir rock analysis in petrophysical and geomechanical experiments, which is done limited in scope due to lack of suitable printing materials and achievable resolution. Following our previous studies on gypsum powder with binder, a new printing material, silica sand, is used and characterized in this study to demonstrate the microstructure and its similarity to Berea Sandstone. Binder jetting printing system was specifically utilized to bond silica sand particles to create intact cylindrical samples without digital porous model as input. Created samples were first scanned by Backscattered Scanning Electron Microscope (BS-SEM) and Energy Dispersive Spectroscopy (EDS) to identify the particles, the packing mode and cement (binder). Next, micro-computed tomography (CT) was used to determine the microstructure of the samples, including the size and the shape of both particles and pores, in the 3D space. In addition, anisotropy that was found to originate from the pore structures was quantified by comparing the characteristics of pores in different directions. Fractal dimensions from different sample sizes, 6?mm and 12?mm in diameter, were also calculated for pore structure analysis in order to illustrate the effect of sample size on pore heterogeneity in 3D printed samples with silica. The results demonstrated the feasibility of substituting 3D-printed sandstones for natural rocks regarding pore structures for experimental validation of petrophysical models.Kooli, W.M., Junier, T., Shakya, M., Monachon, M., Davenport, K.W., Vaideeswaran, K., Vernudachi, A., Marozau, I., Monrouzeau, T., Gleasner, C.D., McMurry, K., Lienhard, R., Rufener, L., Perret, J.-L., Sereda, O., Chain, P.S., Joseph, E., Junier, P., 2019. Remedial treatment of corroded iron objects by environmental Aeromonas isolates. Applied and Environmental Microbiology 85, Article e02042-18.: Using bacteria to transform reactive corrosion products into stable compounds represents an alternative to traditional methods employed in iron conservation. Two environmental Aeromonas strains (CA23 and CU5) were used to transform ferric iron corrosion products (goethite and lepidocrocite) into stable ferrous iron-bearing minerals (vivianite and siderite). A genomic and transcriptomic approach was used to analyze the metabolic traits of these strains and to evaluate their pathogenic potential. Although genes involved in solid-phase iron reduction were identified, key genes present in other environmental iron-reducing species are missing from the genome of CU5. Several pathogenicity factors were identified in the genomes of both strains, but none of these was expressed under iron reduction conditions. Additional in vivo tests showed hemolytic and cytotoxic activities for strain CA23 but not for strain CU5. Both strains were easily inactivated using ethanol and heat. Nonetheless, given a lesser potential for a pathogenic lifestyle, CU5 is the most promising candidate for the development of a bio-based iron conservation method stabilizing iron corrosion. Based on all the results, a prototype treatment was established using archaeological items. On those, the conversion of reactive corrosion products and the formation of a homogenous layer of biogenic iron minerals were achieved. This study shows how naturally occurring microorganisms and their metabolic capabilities can be used to develop bio-inspired solutions to the problem of metal corrosion.Importance: Microbiology can greatly help in the quest for a sustainable solution to the problem of iron corrosion, which causes important economic losses in a wide range of fields, including the protection of cultural heritage and building materials. Using bacteria to transform reactive and unstable corrosion products into more-stable compounds represents a promising approach. The overall aim of this study was to develop a method for the conservation and restoration of corroded iron items, starting from the isolation of iron-reducing bacteria from natural environments. This resulted in the identification of a suitable candidate (Aeromonas sp. strain CU5) that mediates the formation of desirable minerals at the surfaces of the objects. This led to the proof of concept of an application method on real objects.Korochantseva, E.V., Buikin, A.I., Verchovsky, A.B., Lorenz, C.A., Korochantsev, A.V., 2018. Noble gases, nitrogen and carbon isotopic compositions of the Ghubara meteorite, revealed by stepwise combustion and crushing methods. Geochemistry International 56, 1384-1397. Ghubara meteorite contains abundant trapped gases in voids of highly retentive phases that can be released by stepwise crushing and thermal degassing. Their composition is dominated by the solar wind component and by radiogenic argon. We favor a scenario in which a large impact event on L-chondrite asteroid 470 Ma ago caused release, mobilization, fractionation and redistribution of accumulated gases on the Ghubara parent body. The Ghubara breccia was formed at that event and occluded trapped gases into the voids. The uncommonly high 20Ne/36Ar ratios of the analysed samples compared to the solar composition is considered to be due to trapping of gases released from surrounding rocks that lost light noble gases preferentially over the heavy ones. The 4He/20Ne and 4He/36Ar ratios, being as usually lower than in solar wind, gradually increase during stepped crushing, indicating non equilibrium distribution of the gases between the voids of different sizes that can be caused by the dynamics of the shock metamorphism process. The neon isotopic composition released by stepwise crushing and combustion is a mixture of two components: solar dominating trapped and cosmogenic Ne. The former component is mainly degassed in the initial crushing steps opening the large inclusions/voids, while the relative contribution of the latter, likely released from galactic cosmic ray produced tracks, increases with progressive crushing. During stepwise combustion the same trend in the release of the Ne components with increasing temperature is observed. The nitrogen and carbon abundances as well as their isotopic compositions in Ghubara are usual for ordinary chondrites. Most of nitrogen is chemically bounded and associated with carbon. The delivery time of Ghubara from the parent body asteroid to the Earth calculated from its exposure age is 9–28 Ma.Kowalczyk, J.B., Royer, D.L., Miller, I.M., Anderson, C.W., Beerling, D.J., Franks, P.J., Grein, M., Konrad, W., Roth-Nebelsick, A., Bowring, S.A., Johnson, K.R., Ramezani, J., 2018. Multiple proxy estimates of atmospheric CO2 from an Early Paleocene rainforest. Paleoceanography and Paleoclimatology 33, 1427-1438. Proxy estimates of atmospheric CO2 are necessary to reconstruct Earth's climate history. Confidence in paleo-CO2 estimates can be increased by comparing results from multiple proxies at a single site, but so far this strategy has been implemented only for marine-based techniques. Here we present CO2 estimates for the well-studied early Paleocene Castle Rock site in Colorado using four paleobotanical proxies. Median estimates range from 470 to 813?ppm, demonstrating fair correspondence. The synthesis yields a median of 616?ppm (352-1110?ppm at 95% confidence), considerably higher than previous early Paleocene CO2 estimates (~300?ppm). Ash bed geochronology by the high-precision U-Pb method places the Castle Rock assemblage at 63.844?±?0.097?Ma (fully propagated 2σ error). When these results are placed into the broader context of other Cenozoic CO2 estimates from plant-gas-exchange approaches and coeval estimates of global mean surface temperature, a pattern emerges of an Earth system sensitivity around 3?°C per CO2 doubling during the Paleocene and Eocene, a time with little land ice, then steepening to >7?°C after the Eocene once land ice was present on Antarctica.Koweek, D.A., Forden, A., Albright, R., Takeshita, Y., Mucciarone, D.A., Ninokawa, A., Caldeira, K., 2019. Carbon isotopic fractionation in organic matter production consistent with benthic community composition across a coral reef flat. Frontiers in Marine Science 5, 520. doi: 10.3389/fmars.2018.00520. fluxes on coral reefs (net community production and net community calcification) aggregate the collective activity of all coral reef community members. This integrated approach provides powerful community-level insights, but is unable to resolve the finer-scale contributions of different reef functional groups to the community-scale rates. Tools are required to disaggregate the community-scale approaches and evaluate the performance of co-existing reef functional groups. Such assessments are necessary to improve forecasts of coral reef responses to global and local environmental change. We present results from a coral reef field study on One Tree Island reef in the Great Barrier Reef, off northeastern Australia, in September-October 2016 where we combined observations of total alkalinity, dissolved inorganic carbon (DIC), and the stable isotopic composition of dissolved inorganic carbon (δ 13 C DIC δ13CDIC) to estimate carbon isotopic fractionation during organic matter formation. Portions of the reef with greater abundance of non-calcifying algae fractionated DIC ~5‰ more (stronger preference for 12C) during organic metabolism than did portions of the reef with a greater abundance of calcifiers. These results were consistent across a wide range of assumed isotopic fractionation factors for net calcification. We attribute the observed differences in carbon isotopic fractionation to the metabolic activities of the ecological community underlying each section of the reef, rather than to environmental factors such as light availability or water temperature. The patterns in carbon isotopic fractionation were generally consistent with inferred ratios of calcification to primary production in each reef zone, giving further confidence to our inference that differences in carbon isotopic fractionation may be related to differences in the ecological community on small spatial scales.Krot, A.N., Nagashima, K., Fintor, K., Pál-Molnár, E., 2019. Evidence for oxygen-isotope exchange in refractory inclusions from Kaba (CV3.1) carbonaceous chondrite during fluid-rock interaction on the CV parent asteroid. Geochimica et Cosmochimica Acta 246, 419-435. report on the mineralogy, petrology, and in situ measured oxygen-isotope compositions of three Fluffy Type A Ca,Al-rich inclusions (FTA CAIs) and two amoeboid olivine aggregates (AOAs) from the CV3.1 carbonaceous chondrite Kaba. The FTA CAIs are aggregates of several inclusions composed of spinel, Al,Ti-diopside, and gehlenitic melilite replaced to various degrees by anorthite; they are surrounded by the Wark-Lovering rim layers made of spinel, anorthite, Al-diopside, and forsterite. One of FTA CAIs contains a relict ultrarefractory inclusion composed of Sc-rich Al,Ti-pyroxene, spinel, and Zr-rich oxides. The AOAs are aggregates of Ca- and/or Al-rich minerals (spinel, anorthite, and Al,Ti-diopside) surrounded by forsterite?±?Fe,Ni-metal condensates; Fe,Ni-metal is almost entirely replaced by magnetite and Fe,Ni-sulfides. Neither the FTA CAIs nor the AOAs show evidence for being melted after aggregation, and contain very minor secondary alteration minerals resulted from fluid-rock interaction on the CV parent asteroid. These include magnetite, fayalite, hedenbergite, phyllosilicates, and Fe-bearing Ti-free Al-diopside; secondary anorthite of asteroidal origin is absent in Kaba CAIs and AOAs. There are large variations in Δ17O (deviation from the terrestrial fractionation line?=?δ17O???0.52?×?δ18O) within the individual FTA CAIs and AOAs: anorthite and melilite are systematically 16O-depleted (Δ17O range from ～?14 to ～?2‰) relative to the uniformly 16O-rich forsterite and Al,Ti-diopside (Δ17O?～??25 to ?20?±?2‰, 2σ). Scandium-rich Al,Ti-pyroxene has 16O-poor composition (Δ17O?～??4‰). Many anorthite and melilite analyses plot close to or along mass-dependent fractionation line with Δ17O of ?1.5?±?1‰ (average?±?2SD) defined by the aqueously-formed magnetite and fayalite from Kaba, and, therefore, corresponding to Δ17O of an aqueous fluid that operated on the CV parent asteroid. We conclude that anorthite and probably melilite in the Kaba FTA CAIs and AOAs experienced postcrystallization oxygen-isotope exchange with this fluid. The similar process must have affected plagioclase/plagioclase mesostasis and probably melilite in refractory inclusions and chondrules from CV3 chondrites of higher petrologic types [e.g., Allende (CVoxA3.6) and Efremovka (CVred3.1–3.4)], which appear to have experienced higher temperature metasomatic alteration than Kaba and were subsequently metamorphosed.We conclude that the carbonaceous chondrite anhydrous mineral (CCAM) line defined by oxygen-isotope compositions of whole-rock and mineral separates of Allende CAIs and having a slope of 0.94 is not the primary nebular line. Instead this line results from superposition of the nebular slope-1 line recorded by the primitive chondrule mineral (PCM) line, the mass-dependent fractionation line with slope of ～0.5 defined by the secondary minerals>, and the minerals which experienced oxygen-isotope exchange with an aqueous fluid.Kuang, J., Yarbrough, J., Enayat, S., Edward, N., Wang, J., Vargas, F.M., 2019. Evaluation of solvents for in-situ asphaltene deposition remediation. Fuel 241, 1076-1084. the formation and the accumulation of the deposits, cost-effective cleaning strategies should be applied to remediate and remove the organic solids. The injection of aromatic solvents, usually know as solvent wash, is one of the commonly used techniques to re-dissolve the deposited asphaltenes in the well. To select and develop the best solvents and the most appropriate solvent soaking conditions for asphaltene remediation, a re-dissolution test apparatus using a packed bed column was introduced to evaluate the solvents for in-situ asphaltene deposition remediation under more realistic production conditions. The solvency power of three aromatic solvents and four commercial solvents was determined and compared. Under the current experimental conditions, the injection of p-xylene re-dissolves 31.3% and 69.8% more deposits than the same volume of toluene and aromatic naphtha (A150). Additionally, the solvent wash by toluene/diesel mixture (50/50 by volume) and diesel significantly reduces the re-dissolution efficiency by 31.1% and 74.3% by comparing to toluene. Results also suggest that the screening of chemical solvents based on their solubility parameters may not provide accurate indication on the selection of the best solvent for asphaltene removal. Furthermore, the effects of aging time, occluded oil, soaking temperature, and soaking time were investigated on the removal of asphaltene deposition in the packed bed column. Results show that the existence of the occluded oil during the aging and soaking process weakens the solubility power of the toluene. The solvency power of toluene is enhanced by 11.4% and 24.2% when the soaking temperature increases from 25?°C to 120?°C and the soaking time extends from 1?h to 24?h, respectively. With the proposed technique to assess chemical solvents in the laboratory, the most cost-effective solvent wash strategy can be developed for the in-situ remediation of asphaltene deposition in the wellbore.Kumpan, T., Kalvoda, J., Bábek, O., Holá, M., Kanick?, V., 2019. Tracing paleoredox conditions across the Devonian–Carboniferous boundary event: A case study from carbonate-dominated settings of Belgium, the Czech Republic, and northern France. Sedimentary Geology 380, 143-157. Devonian–Carboniferous boundary was coeval with the Hangenberg Crisis, which is regarded as a first-order mass extinction event related with large sea-level changes and widespread anoxia. This study aims to trace the geochemical paleoproductivity and paleoredox proxies across the Devonian–Carboniferous carbonate-dominated successions of the Namur-Dinant Basin (Belgium, northern France) and the Moravo-Silesian Basin (Czech Republic), located in the Variscan Rhenohercynian Zone. The research was focused on the distribution of oxides (SiO2, Al2O3, Fe2O3, CaO, Na2O, K2O, TiO2, MnO) and trace elements (Th, U, V, Zr, Mo, Zn, Pb, Ni, Cu) measured by ICP-OES and ICP-MS, respectively. The enrichment factors of Mo and U and their ratios were used as the main paleoredox proxies, whereas the enrichment factors of Zn, Cu, Pb, and Ni were employed to trace the paleoproductivity changes. High values of Zr/Al2O3 (>0.001), TiO2/Al2O3 (>0.06), and Fe/Ti (>20) and low values of Al/(Al?+?Fe?+?Mn) (<0.35) coinciding with an increase of paleoredox proxies suggest a possible volcanic and hydrothermal source of nutrients, related to Late Devonian and Early Carboniferous extensional magmatism in the Rhenohercynian domain, although a relationship between higher paleoproductivity and enhanced continental runoff of volcanic material cannot be excluded. The studied Devonian–Carboniferous boundary sections from the Namur-Dinant Basin (Gendron-Celles, Ardennes quarry) reveal three levels with similar vectors of Mo and U enrichments. The pre-crisis Famennian pattern is typical for weakly restricted basins with Fe-Mn redox cycling accompanying vertical fluctuations of the oxic/anoxic chemocline close to the sediment/water interface with the influence of particulate shuttle. The MoEF and UEF patterns corresponding to the unrestricted or weakly restricted basin with alternating suboxic to anoxic conditions are considered to represent the transgressive Hangenberg Black Shale Event. The lower Tournaisian MoEF and UEF patterns fall along a vector in the direction of the strongly restricted marine conditions with prevailing suboxic conditions. In the Moravo-Silesian Basin (Lesní lom section), the pre-crisis Famennian MoEF and UEF vector indicates an unrestricted marine trend which converges with that of restricted systems. Redox conditions range from suboxic to euxinic. In the Tournaisian, MoEF and UEF oscillate between oxic and anoxic conditions and fall along a vector of strongly restricted marine conditions. Increased isolation of both studied basins in the Early Tournaisian is regarded as a reflection of a significant eustatic fall during the Hangenberg Crisis, linked to a severe episode of the Gondwana glaciation. These paleohydrographic patterns have correlative potential that should be considered for a revised Devonian-Carboniferous Boundary definition.Kwon, M., Ho, A., Yoon, S., 2019. Novel approaches and reasons to isolate methanotrophic bacteria with biotechnological potentials: recent achievements and perspectives. Applied Microbiology and Biotechnology 103, 1-8. recent drop in the price of natural gas has rekindled the interests in methanotrophs, the organisms capable of utilizing methane as the sole electron donor and carbon source, as biocatalysts for various industrial applications. As heterologous expression of the methane monooxygenases in more amenable hosts has been proven to be nearly impossible, future success in methanotroph biotechnology largely depends on securing phylogenetically and phenotypically diverse methanotrophs with relatively high growth rates. For long, isolation of methanotrophs have relied on repeated single colony picking after initial batch enrichment with methane, which is a very rigorous and time-consuming process. In this review, three unconventional isolation methods devised for facilitation of the isolation process, diversification of targeted methanotrophs, and/or screening of rapid growers are summarized. The soil substrate membrane method allowed for isolation of previously elusive methanotrophs and application of high-throughput extinction plating technique facilitated the isolation procedure. Use of a chemostat with gradually increased dilution rates proved effective in screening for the fastest-growing methanotrophs from environmental samples. Development of new isolation technologies incorporating microfluidics and single-cell techniques may lead to discovery of previously unculturable methanotrophs with unexpected metabolic potentials and thus, certainly warrant future investigation.Labrado, A.L., Brunner, B., Bernasconi, S.M., Peckmann, J., 2019. Formation of large native sulfur deposits does not require molecular oxygen. Frontiers in Microbiology 10, 24. doi: 10.3389/fmicb.2019.00024. native (i.e. elemental) sulfur deposits can be part of caprock assemblages found on top of or in lateral position to salt diapirs and as stratabound mineralization in gypsum and anhydrite lithologies. The native sulfur is formed when hydrocarbons (i.e. oil or methane) come in contact with sulfate minerals in presence of liquid water. The prevailing concept for native sulfur formation in such settings is sulfide produced by sulfate-reducing bacteria is oxidized to zero-valent sulfur in presence of molecular oxygen (O2). Although possible, such a scenario is problematic because: 1. exposure to oxygen would inhibit microbial sulfate reduction, removing the process that produces sulfide; 2. excess supply with oxygen would convert sulfide into sulfate rather than native sulfur; and 3. to produce large native sulfur deposits, enormous amounts of oxygenated water would need to be brought in close proximity to environments in which ample supply of hydrocarbon sustains sulfate reduction. Stable sulfur isotope data from native sulfur deposits emplaced at a stage after the formation of the host rocks indicate that the sulfur was formed in a setting that had little solute exchange with the ambient environment instead of a system with ample supply with dissolved oxygen. Hence, we deduce that there must be a process for the formation of native sulfur in absence of an external oxidant for sulfide. We hypothesize that accumulation of sulfide in a system with restricted fluid exchange triggers a shift from harmful sulfide to nonhazardous native sulfur production, and that sulfate-reducing organisms, possibly in cooperation with other anaerobic microbial partners, take advantage of this modification of the sulfate reduction process when exposed to sulfide stress. We demonstrate that such a process is thermodynamically feasible and argue that there is evidence that microbes form native sulfur deposits in absence of light and external oxidants such as O2, nitrate, or metal oxides.Lacroix, B., Niemi, N.A., 2019. Investigating the effect of burial histories on the clumped isotope thermometer: An example from the Green River and Washakie Basins, Wyoming. Geochimica et Cosmochimica Acta 247, 40-58. Δ47 clumped isotope thermometer has been applied to multiple studies aimed at reconstructing the paleoelevation and paleoclimate of sedimentary basins and paleosol sequences. Ideally, this technique directly preserves the temperature of carbonate formation, avoiding any speculation on the composition of surface water from which the carbonate precipitated. Recently, however, concerns about post-depositional alteration of the Δ47 isotope signature from the effects of burial and/or diagenetic alteration have arisen, potentially complicating the application of the Δ47 clumped isotope thermometer for determining paleo-surface temperatures.Here we investigate the effect of burial history on mass-47 clumped isotope. To this purpose we collected samples, from the surface and from drill cores, in two different areas of the Greater Green River basin: the Washakie Basin near Rock Springs, Wyoming and the Green River Basin near Pinedale, Wyoming. Both basins are filled with a thick sequence of Eocene lacustrine strata and the thermal histories of both basins are well documented from petroleum prospecting studies. Clumped isotope Δ47 compositions were measured from lacustrine micritic limestones with a range of peak burial depths from 1 to 6.5?km. For samples from the Washakie Basin that did not experience burial depths exceeding ～2000 meters, the measured Δ47 values vary from 0.623‰ to 0.684‰, yielding carbonate formation temperatures consistent with previously hypothesized Paleocene-Eocene surface temperatures. In contrast, samples from the Green River Basin, collected from greater burial depths, demonstrate significantly lower Δ47 values (higher temperatures). The consistency of δ18O values and lack of CL evidence for recrystallization suggest closed-system resetting of the clumped isotope thermometer by either partial solid-state re-ordering or carbonate reprecipitation during burial. The Δ47 values of the deeply buried samples have been compared to values derived from recrystallization and temperature history reordering models (THRMs). Both recrystallization and reordering models are successful at predicting Δ47 reordering at burial temperatures >100?°C. These observations, from samples collected from a basin with a remarkably well-constrained thermal history and geothermal gradient, highlight the challenges in elucidating burial histories or diagenetic processes solely from clumped isotopic compositions.Lahme, S., Enning, D., Callbeck, C.M., Menendez Vega, D., Curtis, T.P., Head, I.M., Hubert, C.R.J., 2019. Metabolites of an oil field sulfide-oxidizing, nitrate-reducing Sulfurimonas sp. cause severe corrosion. Applied and Environmental Microbiology 85, Article e01891-18.: Oil reservoir souring and associated material integrity challenges are of great concern to the petroleum industry. The bioengineering strategy of nitrate injection has proven successful for controlling souring in some cases, but recent reports indicate increased corrosion in nitrate-treated produced water reinjection facilities. Sulfide-oxidizing, nitrate-reducing bacteria (soNRB) have been suggested to be the cause of such corrosion. Using the model soNRB Sulfurimonas sp. strain CVO obtained from an oil field, we conducted a detailed analysis of soNRB-induced corrosion at initial nitrate-to-sulfide (N/S) ratios relevant to oil field operations. The activity of strain CVO caused severe corrosion rates of up to 0.27?millimeters per year (mm y?1) and up to 60-μm-deep pitting within only 9 days. The highest corrosion during the growth of strain CVO was associated with the production of zero-valent sulfur during sulfide oxidation and the accumulation of nitrite, when initial N/S ratios were high. Abiotic corrosion tests with individual metabolites confirmed biogenic zero-valent sulfur and nitrite as the main causes of corrosion under the experimental conditions. Mackinawite (FeS) deposited on carbon steel surfaces accelerated abiotic reduction of both sulfur and nitrite, exacerbating corrosion. Based on these results, a conceptual model for nitrate-mediated corrosion by soNRB is proposed.Importance: Ambiguous reports of corrosion problems associated with the injection of nitrate for souring control necessitate a deeper understanding of this frequently applied bioengineering strategy. Sulfide-oxidizing, nitrate-reducing bacteria have been proposed as key culprits, despite the underlying microbial corrosion mechanisms remaining insufficiently understood. This study provides a comprehensive characterization of how individual metabolic intermediates of the microbial nitrogen and sulfur cycles can impact the integrity of carbon steel infrastructure. The results help explain the dramatic increases seen at times in corrosion rates observed during nitrate injection in field and laboratory trials and point to strategies for reducing adverse integrity-related side effects of nitrate-based souring mitigation.Lange, M., Ni, Z., Criscuolo, A., Fedorova, M., 2019. Liquid chromatography techniques in lipidomics research. Chromatographia 82, 77-100. represent a very diverse group of compounds with?a high variety of physicochemical properties determining their functional activities. For omics-wide identification of lipid species from complex biological samples, several crucial analytical steps including extraction, chromatographic separation and mass spectrometry analysis need to be carefully considered and validated. Here we review applications of three main chromatography techniques—reversed phase, normal phase and hydrophilic interaction liquid chromatography—for analysis of complex natural lipidomes aiming to uncover the diversity of lipid species. To correlate lipid separation with their physicochemical properties, lipid chemical space was reconstructed and used to explain principles underlying different chromatographic techniques. Furthermore, examples of available methods for analysis of complex natural lipidomes characterized by high diversity and dynamic range of lipid concentrations are illustrated for adipose tissue lipidomics.Larik, I.A., Qazi, M.A., Phulpoto, A.H., Haleem, A., Ahmed, S., Kanhar, N.A., 2019. Stenotrophomonas maltophilia strain 5DMD: an efficient biosurfactant-producing bacterium for biodegradation of diesel oil and used engine oil. International Journal of Environmental Science and Technology 16, 259-268. study relates to the application of newly isolated bacterium, Stenotrophomonas maltophilia strain 5DMD, from the drilled mud of Suleman exploratory oil well no. 1 of Oil and Gas Development Company limited, located at District Khairpur, for biodegradation of two petrochemical hydrocarbons, i.e., diesel oil and used engine oil. The bacterium was identified by routine microbiological techniques followed by the 16S rRNA gene sequencing and homology studies. The experiments were performed using mineral salts medium supplemented with diesel oil and used engine oil as a sole carbon and an energy source under specified culture conditions (35?°C, 160?rpm, 24?days). The hydrocarbon biodegradation rates were estimated in terms of % removal using UV–Vis spectrophotometer, while characteristic spectral changes in both hydrocarbons were confirmed through Attenuated Total Reflectance-Fourier Transform Infrared spectrometry. Consequently, significant degradation rates of 88.5 and 71.8% for were achieved during the experiment. Moreover, the bacterium has also displayed excellent potential for the production of biosurfactants (oil displacement assay?=?>?6?mm; surface tension?=?33.9 and 34.4?m?N?m?1) and lipase enzyme (Lipolytic zone?=?1.8?±?0.1?cm and 2.2?±?0.3?cm). Fourier transform infrared spectrometry analyses exhibited substantial changes in % transmittance in the frequency range for characteristic of functional groups of aliphatic (1000–600 and 3000–2800?cm?1) and aromatic (1500–1300 and 1055–1000?cm?1) hydrocarbons in diesel oil and used engine oil, confirming the biodegradation. Therefore, S. maltophilia strain 5DMD could be exploited further for future environmental applications and biosynthesis of surfactants or enzymes.Laurent, B., Cousins, C.R., Gunn, M., Huntly, C., Cross, R., Allender, E., 2019. UV luminescence characterisation of organics in Mars-analogue substrates. Icarus 321, 929-937. of organic matter is one of the core objectives of future Mars exploration. The ability to probe rocks, soils, and other geological substrates for organic targets is a high priority for in situ investigation, sample caching, and sample return. UV luminescence—the emission of visible light following UV irradiation—is a tool that is beginning to be harnessed for planetary exploration. We conducted? UV photoluminescence analyses of (i) Mars analogue sediments doped with polyaromatic hydrocarbons (PAHs; <15?ppm), (ii) carbonaceous CM chondrites and terrestrial kerogen (Type IV), and (iii) synthetic salt crystals doped with PAHs (2?ppm). We show that detection of PAHs is possible within synthetic and natural gypsum, and synthetic halite. These substrates show the most apparent spectral modifications, suggesting that the most transparent minerals are more conducive to UV photoluminescence detection of trapped organic matter. Iron oxide, ubiquitously present on Mars surface, hampers but does not completely quench the UV luminescence emission. Finally, the maturity of organic carbonaceous material influences the luminescence response, resulting in a reduced signal for UV excitation wavelengths down to 225?nm. This study demonstrates the utility of UV luminescence spectroscopy for the analysis of mixed organic-inorganic materials applicable to Mars exploration.Le Bris, N., Yücel, M., Das, A., Sievert, S.M., LokaBharathi, P., Girguis, P.R., 2019. Hydrothermal energy transfer and organic carbon production at the deep seafloor. Frontiers in Marine Science 5, 531. doi: 10.3389/fmars.2018.00531. just four decades, hundreds of hydrothermal vent fields have been discovered, widely distributed along tectonic plate boundaries on the ocean floor. Vent invertebrate biomass reaching up to tens of kilograms per square meter has attracted attention as a potential contributor to the organic carbon pool available in the resource-limited deep sea. But the rate of chemosynthetic production of organic carbon at deep-sea hydrothermal vents is highly variable and still poorly constrained. Despite the advent of molecular techniques and in situ sensing technologies, the factors that control the capacity of vent communities to exploit the available chemical energy resources remain largely unknown. Here, we review key drivers of hydrothermal ecosystem productivity, including a) the diverse mechanisms governing energy transfer among biotic and abiotic processes; b) the tight linkages among these processes; and c) the nature and extent of spatial and temporal diversity within a variety of geological settings; and d) the influence of these and other factors on the turnover of microbial primary producers, including those associated with megafauna. This review proposes a revised consideration of the pathways leading to the biological conversion of inorganic energy sources into biomass in different hydrothermal habitats on the seafloor. We propose a conceptual model that departs from the canonical conservative mixing-continuum paradigm by distinguishing low-temperature diffuse flows (LT-diffuse flows) derived from seawater and high-temperature fluids (HT-diffuse flow) derived from end-member fluids. We further discuss the potential for sustained organic matter production at vent-field scale, accounting for the natural instability of hydrothermal ecosystems, from the climax vent communities of exceptional productivity to the long-term lower-activity assemblages. The parameterization of such a model crucially needs assessment of in situ rates and of the largely unrecognized natural variability on relevant temporal scales. Beyond the diversity of hydrothermal settings, the depth range and water mass distribution over oceanic ridge crests, volcanic arcs and back-arc systems is expected to significantly influence biomass production rates. A particular challenge is to develop observing strategies that will account for the full range of environmental variables while attempting to derive global or regional estimates.Lebanov, L., Tedone, L., Kaykhaii, M., Linford, M.R., Paull, B., 2019. Multidimensional gas chromatography in essential oil analysis. Part?1: Technical developments. Chromatographia 82, 377-398. gas chromatography (MDGC) is now established as a technique which can help resolve most of the co-elution problems presenting with conventional gas chromatography for highly complex samples. Essential oils (EOs) are often used in the optimisation and development of novel MDGC methods and related technologies, to demonstrate and assess performance. In this review, recent trends and technical developments in the optimisation of MDGC, modulation and system configuration, pertinent and applied to EO analysis, will be critically discussed. Optimisation of MDGC will be discussed with reference to different column configurations, modulation periods and detection. Attention is given to novel modulation systems, development of multiplex MDGC systems and new approaches which combine heart-cut and comprehensive modes within one system. A section of this review will be dedicated to the preparative application of the MDGC and its application in the isolation of less abundant compounds from complex EO matrices.Lee, E., Hornafius, J.S., Dean, E., Kazemi, H., 2019. Potential of Denver Basin oil fields to store CO2 and produce Bio-CO2-EOR oil. International Journal of Greenhouse Gas Control 81, 137-156. capacity of the Denver Basin to store CO2 in hydrocarbon reservoirs was analyzed using two techniques. The first approach employed by the Southwest Carbon Partnership assumes CO2 is injected into depleted hydrocarbon reservoirs but no fluids are withdrawn. The second method analyzes the storage capacity of the Denver Basin assuming CO2 is injected until the pressure in each oil reservoir reaches the hydrostatic gradient, and CO2 then continues to be injected into the oil reservoirs in order to recover additional oil, until the incremental oil recovery would no longer be commercially viable. The amount of CO2 sequestered in the 30 oil fields studied was found to be 160?Mt with the first method but only 50 to 70?Mt using the second method. If the CO2 source is fermentation emissions available from corn ethanol plants in Nebraska, and the produced bio-CO2-EOR oil is refined into gasoline that is consumed in Colorado, then the CO2 sequestration project described in this paper could reduce the GHG emissions from the transportation sector in Colorado by 10% during peak oil production from the project.Lee, J.H., Yoo, W., Lee, K.S., 2019. Effects of aqueous solubility and molecular diffusion on CO2-enhanced hydrocarbon recovery and storage from liquid-rich shale reservoirs. Energy Sources, Part A: Recovery, Utilization, and Environmental Effects 41, 1230-1241. study investigates the effects of aqueous solubility and aqueous molecular diffusion of gaseous components (CO2 and CH4) on the CO2 huff and puff process in the liquid-rich shale reservoirs. In a gas-condensate reservoir, the effects negligibly enhance the hydrocarbon production, but increase the CO2 storage with 4.4% by solubility trapping. In a shale oil reservoir, they increase the production and CO2 storage up to 5% and 14% by more CO2 imbibition and contacting between CO2 and oil. This study clarifies the importance of aqueous solubility and aqueous-phase molecular diffusion of CO2 huff and puff in shale reservoirs.Lee, Y.K., Lee, M.-H., Hur, J., 2019. A new molecular weight (MW) descriptor of dissolved organic matter to represent the MW-dependent distribution of aromatic condensation: Insights from biodegradation and pyrene binding experiments. Science of The Total Environment 660, 169-176. this study, we utilized a size exclusion chromatography (SEC) system that was equipped with a fluorescence emission scanning mode to explore the heterogeneous distribution of the humification index (HIX) values within bulk dissolved organic matter (DOM). The HIX-based SEC chromatograms showed that the molecular weight (MW)-dependent distribution of aromatic condensation was heavily affected by the DOM sources and the progress of biodegradation. The HIX heterogeneity across different MW was more pronounced for terrestrial versus aquatic DOM sources. Microbial incubation of leaf litter DOM led to the initial enhancement of the HIX at a relatively low MW, followed by a gradual increase at larger MW values. The dynamic changes of the HIX can be attributed to (1) the preferential removal of non-aromatic or less-aromatic molecules by microorganisms, (2) the production of microbial metabolites, (3) microbial humification, and (4) self-assemblage of humic-like molecules. From the SEC chromatograms, the HIX-based average molecular weight (or MWHIX) was proposed as a unifying surrogate to represent an MW that was highly associated with aromatic condensation. The MWHIX discriminated four different DOM sources and described well the biodegradation-induced changes. The MWHIX also presented a good positive correlation with pyrene organic carbon-normalized binding coefficients (Koc). The prediction capability of the MWHIX for pyrene Koc was higher than those based on the single descriptors of bulk DOM, such as HIX and MW, which revealed its superior linkage with the DOM reactivity related to both MW and HIX.Leefmann, T., Frickenhaus, S., Koch, B.P., 2019. UltraMassExplorer: a browser-based application for the evaluation of high-resolution mass spectrometric data. Rapid Communications in Mass Spectrometry 33, 193-202.: High‐resolution mass spectrometry (HRMS) with high sample throughput has become an important analytical tool for the analysis of highly complex samples and data processing has become a major challenge for the user community. Evaluating direct‐infusion HRMS data without automated tools for batch processing can be a time‐consuming step in the analytical pipeline. Therefore, we developed a new browser‐based software tool for processing HRMS data.Methods: The software, named UltraMassExplorer (UME), was written in the R programming language using the shiny library to build the graphical user interface. The performance of the integrated formula library search algorithm was tested using HRMS data derived from analyses of up to 50 extracts of marine dissolved organic matter.Results: The software supports the processing of lists of calibrated masses of neutral, protonated or deprotonated molecules, with masses of up to 700?Da and a mass accuracy <3?ppm. In the performance test, the number of assigned peaks per second increased with the number of submitted peaks and reached a maximum rate of 4745 assigned peaks per second.Conclusions: UME offers a complete data evaluation pipeline comprising a fast molecular formula assignment algorithm allowing for the swift reanalysis of complete datasets, advanced filter functions and the export of data, metadata and publication‐quality graphics. Unique to UME is a fast and interactive connection between data and their visual representation. UME provides a new platform enabling an increased transparency, customization, documentation and comparability of datasets.Lei, Z., Dong, L., Kang, S., Huang, Y., Li, Z., Yan, J., Shui, H., Wang, Z., Ren, S., Pan, C., 2019. Dissociation behaviors of coal-related model compounds in ionic liquids. Fuel 241, 1019-1025. liquids have demonstrated to be promising solvents for processing coal and biomass. Aiming to exploit ionic liquids (ILs) as media for degradation of coal, diphenylmethane (DPM), diphenyl ether (DPE), and diphenyl ketone (DPK) were used as coal-related compounds to study the degradation behaviors of weak-bond structures of coal in ionic liquids in this work. It was found that 1-sulfonic acid butyl-3-methylimidazolium 14 trifluoromethanesulfonate ([B(SO3H)mim]OTf), 1-ethyl-3-methylimidazolium acetate ([Emim]Ac) and 1-butyl-3-methyl-imidazolium chloride ([Bmim]Cl) have a significant effect on the thermal dissociation of the model compounds. [B(SO3H)mim]OTf has a significant effect on the cleavage of DPM and DPK. [Bmim]Cl promotes the cleavage of the DPE. The dissociation effect of the model compound under the action of ionic liquid increases with the increase of reaction temperature. The interaction between the oxygen-containing functional groups in the model compound promotes the respective thermal dissociation of the model compounds. Ionic liquids promote the dissociation interaction of bridge bonds in model compounds. Under the action of ionic liquids, the carbonyl bond promotes the cleavage of the methylene and ether bond cleavage, and the ether bond promotes the methylene bond cleavage.León y León, I.A., Bralower, T.J., Self-Trail, J.M., 2018. Ecological changes in the nannoplankton community across a shelf transect during the onset of the Paleocene-Eocene thermal maximum. Paleoceanography and Paleoclimatology 33, 1396-1407. and other environmental changes during the Paleocene-Eocene thermal maximum (PETM) led to profound shifts in the composition and structure of nannoplankton assemblages. Here we analyze the nature of these changes in expanded records from the Cambridge-Dorchester and Mattawoman Creek-Billingsley Road cores in Maryland. These cores comprise part of a transect of five paleoshelf cores from Maryland and New Jersey. We integrate multivariate analysis of assemblage data with proxy data to revise understanding of the paleoecological affinities of key species. In particular, Discoaster and Fasciculithus are interpreted as thermophiles without adaptation to particular nutrient levels, while Hornibrookina is considered an opportunist adapted to highly variable nearshore environments. Together the cores show consistent margin-wide changes across the onset of the PETM, including a pulse of preevent warming, possibly combined with lower salinity, high seasonality, or increased turbidity. The event itself was characterized by continued warming and eutrophication across the paleoshelf. The Maryland sites experienced higher environmental variability as a result of their proximity to large river systems.Li, D.-W., Xiang, R., Wu, Q., Kao, S.-J., 2019. Planktic foraminifera-bound organic nitrogen isotopic composition in contemporary water column and sediment trap. Deep Sea Research Part I: Oceanographic Research Papers 143, 28-34. foraminifera-bound organic nitrogen isotopes (FB-δ15N) archived in sediments provide an opportunity to reveal past changes in marine nitrogen cycling in the upper water column. However, detailed knowledge about living foraminifera FB-δ15N is still critically lacking. This study presents the FB-δ15N analysis of planktic foraminifera collected from plankton tows and sediment traps in the South China Sea and the Bay of Bengal. Tests of Globigerinoides sacculifer with- and without-sac like chamber from plankton tows showed almost identical FB-δ15N values, suggesting that high thermocline δ15N is not incorporated into the carbonate tests during gametogenic calcification. Sediment trap samples revealed that species dwelling in the upper euphotic zone, such as Globigerinoides sacculifer, contained slightly depleted FB-δ15N relative to the deeper-dwelling species, such as Orbulina universa and Globigerinella siphonifera. The three species also contained FB-δ15N similar to δ15N of the suspended particulate organic matter at corresponding dwelling depths. Our results confirm the increase in FB-δ15N from shallower-dwelling species to deeper-dwelling species and these FB-δ15N differences (Δ15Nvertical) between shallower- and deeper-dwelling species may shed light on the nitrogen dynamics of the euphotic zone in the South China Sea, which is under the influence of the East Asian winter monsoon.Li, F., Wang, M., Liu, S., Hao, Y., 2019. Pore characteristics and influencing factors of different types of shales. Marine and Petroleum Geology 102, 391-401. in China mainly fall into three categories, namely marine, transitional and lacustrine shales. Various shales have different pore characteristics. We studied the formation, occurrence, pore types and morphological characteristics of micropores, mesopores and macropores in different types of shales through the approaches of gas adsorption and mercury injection. Our study found that the marine shale samples have larger specific surface area and pore volume, providing a good hosting space for adsorption gas and free gas. Furthermore, marine samples are dominated by ink-bottle pores, which are conducive to adsorption of shale gas. Continental and transitional pore types are mainly open pores, characterized by good pores’ connectivity that is conducive to the migration of shale gas. The main factors controlling the pore characteristics of the three types of shales were analyzed by investigating specific surface area, pore volume, organic content, clay mineral content, maturity and burial depth. Our study demonstrated that specific surface area and pore volume development have a good correlation with organic matter in the three types of shales. Types of organic matter can affect the development of organic pores. The discrepancy in occurrence of organic matter leads to different correlations between the three types of shales and clay minerals. On the other hand, maturity impacts on pores of shales in two aspects: organic matter and clay mineral transformation. Meanwhile, compaction and dissolution of organic acid in hydrocarbon-generation process are proved to be especially important to pore structure transformation.Li, H., Qin, D., Wu, Z., Sun, B., Sun, X., Huang, M., Sun, J., Zheng, F., 2019. Characterization of key aroma compounds in Chinese Guojing sesame-flavor Baijiu by means of molecular sensory science. Food Chemistry 284, 100-107. odorants of Guojing sesame-flavor Baijiu were identified using the concept of molecular sensory science, including aroma extract dilution analysis (AEDA) based on gas chromatography-olfactometry (GC–O) combined with gas chromatography-mass spectrometry (GC–MS). A total of 509 volatile compounds were detected by comprehensive two-dimensional gas chromatography/time-of-flight mass spectrometry (GC×GC–TOF–MS). Sixty-one aroma-active compounds were identified via AEDA. Among them, two compounds with strong roasted aroma showed the highest flavor dilution (FD) factors of 19683 and 6561. By using pure standards, aroma tests, and GC–MS, the compound with FD = 19683 was identified as benzenemethanethiol, which is reported for the first time in Baijiu. Sixty compounds were quantified by means of internal standard curve method, and 39 of them had odor activity values (OAVs) ≥ 1. Ethyl hexanoate, ethyl octanoate, and dimethyl trisulfide showed the highest OAVs, indicating that they contribute significantly to the aroma of Guojing sesame-flavor Baijiu.Li, H., Xu, Y., Wang, F., Luo, X., Yu, H., 2019. Geochemical characteristics and sources of oil and gas in deep buried hills, Bohai Sea area. Natural Gas Industry 39, 45-56 hydrocarbon-rich deep subsags are developed in the periphery of the BZ19-6 deep buried-hill structural belt in the Bohai Sea area, Bohai Bay Basin, and their hydrocarbon accumulation conditions are complicated. So far, the organic geochemical characteristics and main sources of their oil and gas have not been figured out. In this paper, the geochemical characteristics of crude oil and natural gas in this belt and those of the source rocks of hydrocarbon-rich deep subsags around the buried-hill structure belt were analyzed by means of geochemical testing technologies, such as saturated hydrocarbon and light hydrocarbon chromatography, chromatography–mass spectrometry, detection of natural gas components and carbon isotope components. Then, the sources and characteristics of oil and gas in the BZ19-6 deep buried-hill structural belt were studied systematically by using the oil-source biomarker analysis technology. And the following research results were obtained. First, in the peripheral sags of this belt are mainly developed four sets of source rocks, i.e., the lower submember of the second Member of Paleogene Dongying Fm (E2d21), the third Member of Dongying Fm (E2d3), the first Member of Shahejie Fm (E2s1) and the upper submember of the third Member of Shahejie Fm (E2s32). Among them, E2d3 and E2s32 are the principal hydrocarbon source kitchens. Their organic abundance is relatively high and their organic matter is of sapropel-prone mixed type. And now they are in the peak stage of hydrocarbon generation. Second, natural gas in the Archean deep buried hill and its overlying Paleogene Kongdian Fm (E1k) is typical oil-type gas. It presents the mixed characteristics of natural gas with different maturities and multiple stages of hydrocarbon accumulation process. Third, the source of oil and gas in shallow layers is different from that in deep layers, though they both present the mixed source input characteristics of three sets of source rocks. The oil and gas in shallow layers is mainly derived from E2d3 source rocks and possibly from E2d21 source rocks, while the oil and gas in deep layers is mainly derived from E2s32 source rocks. In conclusion, the hydrocarbon source conditions in this area are complex, the hydrocarbon source is mainly contributed by the E2s32 source rocks in the hydrocarbon-rich deep subsags in the periphery of this belt, and the deep condensate gas reservoirs are characterized by multi-stage oil-type gas input.Li, J., Lu, S., Chen, G., Wang, M., Tian, S., Guo, Z., 2019. A new method for measuring shale porosity with low-field nuclear magnetic resonance considering non-fluid signals. Marine and Petroleum Geology 102, 535-543. is a key parameter for the evaluation of potential shale oil and gas resources. Low-field nuclear magnetic resonance (NMR) is a rapid technique for measuring shale porosity without causing damage to the testing samples. Previous NMR methods for porosity characterization are mainly based on the NMR T2 distribution of saturated oil shale, but for shales with high total organic carbon (TOC) and clay mineral contents, not all signals of NMR detection originate from the pore fluid. Nine continental shales in Damintun Sag were selected and subjected to pyrolysis, X-ray diffraction (XRD), mercury injection capillary pressure (MICP), weighing before and after fluid saturation, and NMR tests to improve the accuracy of NMR porosity measurements. According to the NMR T2 distribution and T1–T2 map of shale with different oil contents (original, extracted, and saturated oil states), we revealed that the non-fluid signals (kerogen and structural water) accounted for 15.77%–43.10% (with a mean of 28.87%) of saturated oil shale. A stronger NMR signal intensity was observed for the extracted shale with higher TOC and clay mineral contents. A ΔT2 distribution of oil present in the pores of oil-saturated shale was constructed based on the difference between the oil-saturated shale and extracted shale and was combined with the calibration equation of oil (the relationship between oil volume and its NMR signal intensity) to directly evaluate the porosity. The porosity that was calculated based on the ΔT2 distribution versus the weighing method had an absolute error of ≤0.7%, and the relative error was <10%. Compared with the previous NMR method, the new method does not require optimization of the NMR parameters and considers the contribution of organic matter and clay minerals to NMR signals, which is more suitable for the porosity evaluation of shales with high TOC and clay mineral contents. The results of this study are helpful for NMR characterization of the porosity in shales.Li, W.-L., Huang, J.-M., Zhang, P.-W., Cui, G.-J., Wei, Z.-F., Wu, Y.-Z., Gao, Z.-M., Han, Z., Wang, Y., 2019. Periodic and spatial spreading of alkanes and Alcanivorax bacteria in deep waters of the Mariana Trench. Applied and Environmental Microbiology 85, Article e02089-18.: In subduction zones, serpentinization and biological processes may release alkanes to the deep waters, which would probably result in the rapid spread of Alcanivorax. However, the timing and area of the alkane distribution and associated enrichment of alkane-degrading microbes in the dark world of the deep ocean have not been explored. In this study, we report the richness (up to 17.8%) of alkane-degrading bacteria, represented by Alcanivorax jadensis, in deep water samples obtained at 3,000 to 6,000 m in the Mariana Trench in two cruises. The relative abundance of A. jadensis correlated with copy numbers of functional almA and alkB genes, which are involved in alkane degradation. In these water samples, we detected a high flux of alkanes, which probably resulted in the prevalence of A. jadensis in the deep waters. Contigs of A. jadensis were binned from the metagenomes for examination of alkane degradation pathways and deep sea-specific pathways, which revealed a lack of nitrate and nitrite dissimilatory reduction in our A. jadensis strains. Comparing the results for the two cruises conducted close to each other, we suggest periodic release of alkanes that may spread widely but periodically in the trench. Distribution of alkane-degrading bacteria in the world’s oceans suggests the periodic and remarkable contributions of Alcanivorax to the deep sea organic carbon and nitrogen sources.Importance: In the oligotrophic environment of the Mariana Trench, alkanes as carbohydrates are important for the ecosystem, but their spatial and periodic spreading in deep waters has never been reported. Alkane-degrading bacteria such as Alcanivorax spp. are biological signals of the alkane distribution. In the present study, Alcanivorax was abundant in some waters, at depths of up to 6,000?m, in the Mariana Trench. Genomic, transcriptomic, and chemical analyses provide evidence for the presence and activities of Alcanivorax jadensis in deep sea zones. The periodic spreading of alkanes, probably from the subductive plates, might have fundamentally modified the local microbial communities, as well as perhaps the deep sea microenvironment.Li, W., Liu, Z., Su, E., Cheng, Y., 2018. Experimental investigation on the effects of supercritical carbon dioxide on coal permeability: Implication for CO2 injection method. Energy & Fuels 33, 503-512. storage in deep unrecoverable coal seams has become an effective method to curb greenhouse gas emission, which also contributes to an increase in coalbed methane (CBM) production. Due to high temperature and pressure in deep coal seams, the injected CO2 remains in a supercritical state. However, the influence of injecting supercritical CO2 into coal seams on coal permeability is not particularly clear at present. Therefore, this paper conducted a series of studies through high-pressure triaxial setups on the naturally fractured coal, the coal adsorbing supercritical CO2 for different times, and supercritical CO2-treated coal, respectively. In the experiment, the laws of coal permeability variation with different adsorption times of supercritical CO2 under different gas injection pressure were first determined. Results indicate that there is a decline in coal permeability in the initial stage because of the great swelling deformation induced by adsorption. Besides, the coal may find a rebound in permeability in the later phase if its mechanical properties have been changed after repeated adsorption. Meanwhile, He was applied to measuring the permeability of original coal and the coal completely desorbing supercritical CO2, respectively. On the basis of a comparison between their permeability values, the latter has higher permeability. It directly indicates that supercritical CO2 has extraction and dissolution effects on organic matter and inorganic minerals in coal, respectively, thus enhancing the permeability. To further support this point of view, pore characteristics of such two kinds of coal were determined through mercury intrusion method. It is demonstrated that the supercritical CO2-treated coal has well developed and connected pore system, with a rise in the proportion of meso- and macro-pores as well as total pore volume. In addition, the coal with different adsorption times varies in permeability evolution laws under the same effective stress. Inspired by such variation, this paper proposed a new gas injection method, that is, injection pressure rose gradually after cyclic adsorption of supercritical CO2, which provides a certain reference for efficient gas injection.Li, X.-M., Chen, Q.-L., He, C., Shi, Q., Chen, S.-C., Reid, B.J., Zhu, Y.-G., Sun, G.-X., 2019. Organic carbon amendments affect the chemodiversity of soil dissolved organic matter and its associations with soil microbial communities. Environmental Science & Technology 53, 50-59. “4 per mil” initiative recognizes the pivotal role of soil in carbon resequestration. The need for evidence to substantiate the influence of agricultural practices on chemical nature of soil carbon and microbial biodiversity has become a priority. However, owing to the molecular complexity of soil dissolved organic matter (DOM), specific linkages to microbial biodiversity have eluded researchers. Here, we characterized the chemodiversity of soil DOM, assessed the variation of soil bacterial community composition (BCC), and identified specific linkages between DOM traits and BCC. Sustained organic carbon amendment significantly (P < 0.05) increased total organic matter reservoirs, resulted in higher chemodiversity of DOM and emergence of recalcitrant moieties (H/C < 1.5). In the meantime, sustained organic carbon amendment shaped the BCC to a more eutrophic state while long-term chemical fertilization directed the BCC toward an oligotrophic state. Meanwhile, higher connectivity and complexity were observed in organic carbon amendment by DOM–BCC network analysis, indicating that soil microbes tended to have more interaction with DOM molecules after organic matter inputs. These results highlight the potential for organic carbon amendments to not only build soil carbon stocks and increase their resilience but also mediate the functional state of soil bacterial communities.Li, X., Liu, Z., Chen, W., Wang, L., He, B., Wu, K., Gu, S., Jiang, P., Huang, B., Dai, M., 2018. Production and transformation of dissolved and particulate organic matter as indicated by amino acids in the Pearl River Estuary, China. Journal of Geophysical Research: Biogeosciences 123, 3523-3537. Production and transformation of dissolved and particulate organic matter (DOM, POM) in estuaries regulate the carbon export from land to ocean, yet tracing their source and diagenetic status is challenging in these dynamic environments. Here we study the production, transport, and diagenetic status of DOM in the Pearl River Estuary (PRE), China, based on total dissolved amino acids, their enantiomers (D/L ratios), and other ancillary biogeochemical parameters with a complete coverage of upper, middle, and lower estuary. Inferred from amino acid composition and D/L ratios, DOM in the upper PRE was highly altered by bacteria, while the carbon yields of total dissolved amino acids were relatively high showing a conflicting pattern likely contributed by multiple sources including planktonic production, soil leachates, and sewage discharge. Conservative mixing between freshwater and seawater predominantly controlled DOM dynamics in the middle PRE. In contrast, the lower PRE was characterized by high planktonic production, leading to the accumulation of labile DOC in the surface water. The compositional pattern of amino acids differed significantly between dissolved and particulate phases, yet the diagenetic indices of POM and DOM were both relatively lower in the upper and middle PRE compared to the lower PRE, suggesting that primary production is a major driving factor in the lower PRE. Overall, our study emphasizes the highly dynamic and spatially heterogeneous nature of the PRE, and the results from molecular level characterization provide new insights into the complex sources, diagenesis, and transformation processes of DOM in different regions of the estuary, as well as its connection with POM.Li, X., McCarty, G.W., Karlen, D.L., Cambardella, C.A., Effland, W., 2018. Soil organic carbon and isotope composition response to topography and erosion in Iowa. Journal of Geophysical Research: Biogeosciences 123, 3649-3667. redistribution (erosion and deposition) can greatly affect the fate of soil organic carbon (SOC) in agroecosystems. Landscape topography is one of the key factors controlling erosion processes and creating spatial variability in SOC. We combined carbon (C) isoscape (isotopic landscape) analysis, historic orthophoto interpretation, cesium (137Cs) inventory measurement, and digital terrain analysis to quantify SOC dynamics and soil redistribution relationship and their responses to landscape topography in an Iowa cropland field with soybean/maize (C3/C4) rotation. The historic orthophotos and 137Cs were used to reflect soil redistribution before and after the 1960s, respectively. Topography‐based models were developed to simulate 137Cs inventory, SOC density, and C isotopes using stepwise principal component regression. Spatial patterns of SOC were similar to soil erosion/deposition patterns with high SOC density in depositional areas and low SOC density in eroded areas. Soil redistribution, SOC density, and isotopic signature of SOC (δ13C) were highly correlated with topographic metrics, suggesting that topographic heterogeneity drove the spatial variability in erosion and SOC dynamics. Considering the isotopic composition of SOC, C3‐derived SOC density was strongly controlled by topographic metrics, but C4‐derived SOC density showed weaker expression of spatial pattern and poor correlation to topographic parameters. The resulting topography‐based stepwise principal component regression models captured more than 60% of the variability in SOC density, δ13C, and C3‐derived SOC density but could not reliably predict C4‐derived SOC density. Our results indicate that exploring C isotopes in response to soil erosion is important to understand the fate of eroded SOC within croplands under C3/C4 cultivation.Li, Y., Li, Z., Wang, H., Wang, D., 2018. The characteristics of hydrocarbon generation, reserving performances of fine-grained rock, and preservation conditions of coal measure shale gas of an epicontinental sea basin: A case study of the Late Palaeozoic shale gas in the Huanghebei Area of Western Shandong. Energy Exploration & Exploitation 37, 453-472. China, marine and land transitional fine-grained rocks (shale, mudstone, and so on) are widely distributed and are known to have large accumulated thicknesses. However, shale gas explorations of these types of rock have only recently been initiated, thus the research degree is very low. Therefore, this study was conducted in order to improve the research data regarding the gas accumulation theory of marine and continental transitional fine-grained rock, as well as investigate the shale gas generation potential in the Late Paleozoic fine-grained rock masses located in the Huanghebei Area of western Shandong Province. The hydrocarbon generation characteristics of the epicontinental sea coal measures were examined using sedimentology, petrography, geochemistry, oil and gas geology, tectonics, and combined experimental testing processes. The thick fine-grained rocks were found to have been deposited in the sedimentary environments of the tidal flats, barriers, lagoons, deltas, and rivers during the Late Paleozoic in the study area. The most typical fine-grained rocks were located between the No. 5 coal seam of the Shanxi Formation and the No. 10 coal seam of the Taiyuan Formation, with an average thickness of 84.8 m. These formations were mainly distributed in the western section of the Huanghebei Area. The total organic carbon content level of the fine-grained rock was determined to be 2.09% on average, and the higher content levels were located in the western section of the Huanghebei Area. The main organic matter types of the fine-grained rock were observed to be kerogen II, followed by kerogen III. The vitrinite reflectance (Ro) of the fine-grained rock was between 0.72 and 1.25%, which indicated that the gas generation of the dark fine-grained rock was within a favorable range, and the maturity of the rock was mainly in a medium stage in the northern section of the Huanghebei Area. It was determined that the average content of brittle minerals in the fine-grained rock was 55.7%. The dissolution pores and micro-cracks were the dominating pores in the fine-grained rock, followed by intergranular pores and intercrystalline pores. It was also found that both the porosity and permeability of the fine-grained rock were very low in the study area. The desorption gas content of the fine-grained rock was determined to be between 0.986 and 4.328 m3/t, with an average content of 2.66 m3/t. The geological structures were observed to be simple in the western section of the Huanghebei Area, and the occurrence impacts on the shale gas were minimal. However, the geological structures were found be complex in the eastern section of the study area, which was unfavorable for shale gas storage. The depths of the fine-grained rock were between 414.05 and 1290.55 m and were observed to become increasingly deeper from the southwestern section to the northern section. Generally speaking, there were found to be good reservoir forming conditions and great resource potential for marine and continental transitional shale gas in the study area.Li, Z., Yang, W., Wang, Y., Zhang, L., Luo, H., Liu, S., Zhang, L., Luo, X., 2019. Anatomy of a lacustrine stratigraphic sequence within the fourth member of the Eocene Shahejie Formation along the steep margin of the Dongying depression, eastern China. American Association of Petroleum Geologists Bulletin 103, 469-504. comprehensive study on rift stratigraphy requires a solid understanding of sequence architecture along the steep margins of rift basins. This study analyzes an Eocene lacustrine sequence along the steep margin of the Dongying depression in eastern China through integrated core, well-log, and three-dimensional seismic analyses. The lacustrine sequence is bounded by unconformities and their correlative conformities at the base and top and consists of three systems tracts, namely an early expansion systems tract (EEST), late expansion–early contraction systems tract (LEECST), and late contraction systems tract (LCST), which record a lake expansion–contraction cycle. These systems tracts differ in thickness and development of depositional systems. The EEST is the thickest and contains well-developed marginal and basinal fan systems with an overall retrogradational stacking pattern. The well-developed fan systems are the most striking features within the sequence. The LEECST is the most widespread and contains dominantly profundal–sublittoral deposits. The LCST is the thinnest, with poorly developed fan systems, and is characterized by significant erosion by fluvial incision. The variable thickness and development of depositional systems in the three systems tracts are the responses to the interplay of sediment supply and accommodation space. Accommodation space establishes the framework for sedimentary infill, and sediment supply determines spatial distribution and temporal evolution of depositional systems within each systems tract. This study provides a lake expansion–contraction scheme to divide a lacustrine stratigraphic sequence into systems tracts and highlights the feasibility of applying this approach in studying sequence stratigraphy along the steep margin of a lacustrine rift basin. The results also provide understandings for the development, distribution, and evolution of depositional systems and their controlling factors along the steep margin of other rift basins in the world.Liang, C., Huang, Y., Wang, H., 2019. pahE, a functional marker gene for polycyclic aromatic hydrocarbon-degrading bacteria. Applied and Environmental Microbiology 85, Article e02399-18.: The characterization of native polycyclic aromatic hydrocarbon (PAH)-degrading bacteria is significant for understanding the PAH degradation process in the natural environment and developing effective remediation technologies. Most previous investigations of PAH-degrading bacteria in environmental samples employ pahAc, which encodes the α-subunit of PAH ring-hydroxylating dioxygenase, as a functional marker gene. However, the poor phylogenetic resolution and nonspecificity of pahAc result in a misestimation of PAH-degrading bacteria. Here, we propose a PAH hydratase-aldolase-encoding gene, pahE, as a superior biomarker for PAH-degrading bacteria. Comparative phylogenetic analysis of the key enzymes involved in the upper pathway of PAH degradation indicated that pahE evolved dependently from a common ancestor. A phylogenetic tree constructed based on PahE is largely congruent with PahAc-based phylogenies, except for the dispersion of several clades of other non-PAH-degrading aromatic hydrocarbon dioxygenases present in the PahAc tree. Analysis of pure strains by PCR confirmed that pahE can specifically distinguish PAH-degrading bacteria, while pahAc cannot. Illumina sequencing of pahE and pahAc amplicons showed more genotypes and higher specificity and resolution for pahE. Novel reads were also discovered among the pahE amplicons, suggesting the presence of novel PAH-degrading populations. These results suggest that pahE is a more powerful biomarker for exploring the ecological role and degradation potential of PAH-degrading bacteria in ecosystems, which is significant to the bioremediation of PAH pollution and environmental microbial ecology.Importance: PAH contamination has become a worldwide environmental issue because of the potential toxic effects on natural ecosystems and human health. Biotransformation and biodegradation are considered the main natural elimination forms of PAHs from contaminated sites. Therefore, the knowledge of the degradation potential of the microbial community in contaminated sites is crucial for PAH pollution bioremediation. However, the nonspecificity of pahAc as a functional marker of PAH-degrading bacteria has resulted neither in a reliable prediction of PAH degradation potential nor an accurate assessment of degradation. Here, we introduced pahE encoding the PAH hydratase-aldolase as a new and better functional marker gene of PAH-degrading bacteria. This study provides a powerful molecular tool to more effectively explore the ecological role and degradation potential of PAH-degrading bacteria in ecosystems, which is significant to the bioremediation of PAH pollution.Liang, Y., Zhou, T., 2019. Recent advances of online coupling of sample preparation techniques with ultra high performance liquid chromatography and supercritical fluid chromatography. Journal of Separation Science 42, 226-242. Ultra high performance liquid chromatography and supercritical fluid chromatography techniques are favored because of their high efficiency and fast analysis speed. Although many sample preparation techniques have been coupled with common liquid chromatography online, the online coupling of sample preparation with the two popular chromatography techniques have gained increasing attention owing to the increasing requirements of efficiency and sensitivity. In this review, we have discussed and summarized the recent advances of the online coupling of sample preparation with ultra high performance liquid chromatography and supercritical fluid chromatography techniques. The main sample preparation techniques that have been coupled with ultra high performance liquid chromatography online are solid-phase extraction and in-tube solid-phase microextraction, while solid-phase extraction and supercritical fluid extraction are the main techniques that have been coupled with supercritical fluid chromatography online. Especially, the strategies for online coupling of sample preparation with chromatography techniques were summarized. Typical applications and growing trends of the online coupling techniques were also discussed in detail. With the increasing demands of improving the efficiency, throughput, and analytical capability toward complex samples of the analysis methods, online coupling of sample preparation with chromatography techniques will acquire further development.Liigand, J., de Vries, R., Cuyckens, F., 2019. Optimization of flow splitting and make-up flow conditions in liquid chromatography/electrospray ionization mass spectrometry. Rapid Communications in Mass Spectrometry 33, 314-322.: In liquid chromatography/mass spectrometry (LC/MS) the LC flow is often split prior to the mass spectrometer, for instance, when collecting fractions of the separated sample for other purposes or when less sensitive parallel detection is applied. The aim of this study is to optimize the actual split ratio and make‐up flow composition.Methods: Different types of splitters were evaluated in combination with a make‐up flow. A home‐made 1/10?T‐piece splitter and commercial 1/10, 1/100 and 1/250 splitters were evaluated by continuous and accurate measurements of the actual split ratio throughout the LC gradient. The make‐up flow composition was optimized for maximum electrospray ionization (ESI)‐MS sensitivity in the positive mode using ESI efficiency measurements.Results: Altogether 22 different solvent conditions were tested on 20 pharmaceutical compounds with a wide variety of functional groups and physicochemical properties (molecular weight, logP, and pKa). Methanol/10?mM formic acid in water (90/10) provided on average the best results. Conclusions: Methanol/10?mM formic acid in water (90/10) proved to be the best make‐up flow composition in relation to the average sensitivity obtained. Stronger acidic conditions using oxalic acid or higher formic acid concentrations had a clear positive effect on the sensitivity of compounds with low ionization efficiency. The tested split ratios were relatively stable over the main part of the gradient but showed some variation at very low and very high organic conditions. Differences were larger with methanol compared with acetonitrile containing solvent compositions and when applied without a column or with very long connecting tubing.Lima, M.F.B., Fernandes, G.M., Oliveira, A.H.B., Morais, P.C.V., Marques, E.V., Santos, F.R., Nascimento, R.F., Swarthout, R.F., Nelson, R.K., Reddy, C.M., Cavalcante, R.M., 2019. Emerging and traditional organic markers: Baseline study showing the influence of untraditional anthropogenic activities on coastal zones with multiple activities (Ceará coast, Northeast Brazil). Marine Pollution Bulletin 139, 256-262. markers are useful tools to characterize natural and anthropogenic impacts on coastal zones. Distribution of n-alkanes showed that the Pacoti River was predominantly influenced by terrigenous input. Distribution of polycyclic aromatic hydrocarbon (PAH) indices showed a mix of natural sources, especially pyrogenic influences. Sterol and hormone levels showed sewage discharge. Integrated geographic assessment showed that pyrogenic process and sewage discharge are predominant along the river because of natural and different anthropogenic activities. The upstream region is influenced by rural activities such as livestock and discharge from the sewage treatment plant, whereas the estuarine region is influenced by urban and industrial activities, predominantly the discharge of treated or untreated sewage, vehicle traffic, and manufacture of red ceramics. On the other hand, on the river mouth, there is the predominance of aquaculture activities. Traditional anthropogenic markers are not sufficient for producing a comprehensive assessment of anthropogenic impacts in areas with multiple activities.Lingam, M., Loeb, A., 2018. Relative likelihood of success in the search for primitive versus intelligent extraterrestrial life. Astrobiology 19, 28-39. estimate the relative likelihood of success in the searches for primitive versus intelligent life on other planets. Taking into account the larger search volume for detectable artificial electromagnetic signals, we conclude that both searches should be performed concurrently, albeit with significantly more funding dedicated to primitive life. Based on the current federal funding allocated to the search for biosignatures, our analysis suggests that the search for extraterrestrial intelligence (SETI) may merit a federal funding level of at least $10 million per year, assuming that the average lifetime of technological species exceeds a millennium.Linnemann, U., Ovtcharova, M., Schaltegger, U., G?rtner, A., Hautmann, M., Geyer, G., Vickers-Rich, P., Rich, T., Plessen, B., Hofmann, M., Zieger, J., Krause, R., Kriesfeld, L., Smith, J., 2019. New high-resolution age data from the Ediacaran–Cambrian boundary indicate rapid, ecologically driven onset of the Cambrian explosion. Terra Nova 31, 49-58. replacement of the late Precambrian Ediacaran biota by morphologically disparate animals at the beginning of the Phanerozoic was a key event in the history of life on Earth, the mechanisms and the time‐scales of which are not entirely understood. A composite section in Namibia providing biostratigraphic and chemostratigraphic data bracketed by radiometric dating constrains the Ediacaran–Cambrian boundary to 538.6–538.8 Ma, more than 2 Ma younger than previously assumed. The U–Pb‐CA‐ID TIMS zircon ages demonstrate an ultrashort time frame for the LAD of the Ediacaran biota to the FAD of a complex, burrowing Phanerozoic biota represented by trace fossils to a 410 ka time window of 538.99 ± 0.21 Ma to 538.58 ± 0.19 Ma. The extremely short duration of the faunal transition from Ediacaran to Cambrian biota within less than 410 ka supports models of ecological cascades that followed the evolutionary breakthrough of increased mobility at the beginning of the Phanerozoic.Lipka, E., Dascalu, A.-E., Messara, Y., Tsutsqiridze, E., Farkas, T., Chankvetadze, B., 2019. Separation of enantiomers of native amino acids with polysaccharide-based chiral columns in supercritical fluid chromatography. Journal of Chromatography A 1585, 207-212. this short communication preliminary results are reported on the separation of enantiomers of underivatized amino acids on polysaccharide-based chiral columns in sub/super-critical fluid chromatography (SFC). Racemic mixtures of 14 amino acids were used to evaluate the chiral recognition ability of 8 different polysaccharide-based chiral columns with coated or covalently immobilized chiral selectors. Among the studied columns, the one based on cellulose (3,5-dichlorophenylcarbamate) exhibited the most universal chiral recognition ability providing baseline resolution for the enantiomers of 10 studied amino acids. In addition, the effect of mobile phase composition (in particular, of the amount of additive used), as well as the potential contribution of evaporative light scattering detector (ELSD) to extra column band-broadening was evaluated.Liu, A., Ou, W., Huang, H., Wei, K., Li, H., Chen, X., 2018. Significance of paleo-fluid in the Ordovician–Silurian detachment zone to the preservation of shale gas in western Hunan–Hubei area. Natural Gas Industry B 5, 565-574. studies on the paleo-fluid in the Ordovician–Silurian detachment zone in the Middle–Upper Yangtze area focus on the origin of high-density methane inclusions and the evolution process of formation pressure, but rarely deal with the significance of paleo-fluid to shale gas preservation. In this paper, the relationship between fracture formation and detachment zone was analyzed by observing the Ordovician–Silurian outcrops in western Hunan–Hubei area and by investigating the geological characteristics of fracture veins in the drilling cores. Then, the significance of paleo-fluid forming environment and detachment zone to shale gas preservation was studied by using inclusion compositions of fracture veins and homogenization temperature test data. Finally, accumulation–dispersion modes of shale gas in the detachment zone were established. The following results were obtained. First, the detachment zone is lithologically composed of silicite with intercalated shale at the Ordovician–Silurian interface. In the detachment zone, rocks are broken and small crumples are developed. The conjugate-vertical joints are relatively developed in the silicite above and below the detachment zone. Second, multi-stage and multi-type inclusions, especially the aqueous inclusions, are developed in the veins of the detachment zone. Third, the infiltration depth of ancient meteoric water along the detachment zone in the study area is over 4000?m. High-density overpressure methane inclusions were captured in the detachment zone during early stage, while normal-pressure methane and nitrogen inclusions were captured during late stage. Fourth, the ionic constituents of inclusions recording the fluid activity during the late stage was characterized by high sodium-chloride coefficient, high desulfurization coefficient and low metamorphic coefficient, and it is indicated that the sealing capacity of the shale in the detachment zone gets worse. Fifth, the accumulation and dispersion of shale gas in the detachment zone within the study area is divided into three modes, i.e., syncline, broad anticline and closed anticline. In conclusion, the detachment zone in the study area is permeable. Synclines and closed anticlines developed in detachment structures are unfavorable for the accumulation of shale gas, while broad anticlines are favorable.Liu, B., Wang, H., Fu, X., Bai, Y., Bai, L., Jia, M., He, B., 2019. Lithofacies and depositional setting of a highly prospective lacustrine shale oil succession from the Upper Cretaceous Qingshankou Formation in the Gulong sag, northern Songliao Basin, northeast China. American Association of Petroleum Geologists Bulletin 103, 405-432. lacustrine shale of the Upper Cretaceous Qingshankou Formation is the principal prospective unconventional target lithology, acting as source, reservoir, and seal. Lithofacies and associated storage capacity are two significant factors in shale oil prospectivity. This paper describes an investigation of the lower Qingshankou Formation lacustrine shale based on detailed description and analysis of cores, shale lithofacies characteristics, depositional setting, and stacking patterns.Seven lithofacies are recognized based on organic matter content, sedimentary structure, and mineralogy, all exhibiting rapid vertical and lateral changes controlled by the depositional setting and basin evolution. An overall trend from shallow-water to deep-water depositional environments is interpreted from the characteristics of the infilling sequences, characterized by increasing total organic carbon (TOC) and total clay content and decreasing layer thickness (i.e., from bedded to laminated then to massive sedimentary structures). Periods of deposition during shallowing cycles show a reverse trend in the sedimentary characteristics described above. The sedimentary rocks in the studied interval show three complete short-term cycles, each one containing progressive and regressive system tracts.Massive siliceous mudstones with both high and moderate TOC are considered to have the best hydrocarbon generation potential. Laminated siliceous mudstones, bedded siltstones, and calcareous mudstones with moderate and low TOC could have the same high hydrocarbon saturations as the high-TOC massive siliceous mudstones, but these lithologies contain more brittle minerals than the massive mudstones. Several siltstone samples show low or zero saturation of in situ hydrocarbons; this is considered to be related to a combination of fair to poor hydrocarbon generation potential and extremely low permeability, limiting migration. Moderate-TOC laminated siliceous mudstones were also observed to have connective pore-fracture networks. It can be demonstrated that successive thick sequences of moderate-TOC laminated siliceous mudstones, showing high volumes of hydrocarbon in situ, a high mineral brittleness index, and good permeability, combine to form shale oil exploration “sweet spots.”Liu, C., Huang, L., Zhang, D., Zhao, J., Deng, Y., Guo, P., Huang, Y., Wang, J., 2018. Genetic causes of oil-rich and oil-poor reservoirs: Implications from two Cenozoic basins in the eastern North China Craton. Science China Earth Sciences 61, 1910-1931. Bohai Bay and Hehuai (southern North China) rift basins in the eastern part of the North China Craton are south-north-adjacent. They have shown synchronous evolutionary processes, and possess generally identical superficial and shallow structural characteristics as well as similar basin areas. However, there is a large difference in the richness of oil resources between the two basins. The Bohai Bay Basin has extremely abundant oil reserves, while commercial oil reserves have not been found in the Hehuai Basin. The deep tectonic structures, magmatic activities, and modern and paleogeothermal fields of the two basins are significantly different. Compared with the Hehuai Basin, the Bohai Bay Basin has a thinner crust and more complex structure with multiple low-velocity layers. It is also characterized by intense magmatic activity, high modern and paleogeothermal fields, frequent seismic activity, and active deep interactions, small effective elastic thickness of the isotropic lithosphere, and shorter balanced transformation wavelength of the lithosphere with a high likelihood of local compensation. The Hehuai Basin has a simple deep structure and homogeneous crustal composition, with a high likelihood of regional compensation. The characteristics of the deep structures mentioned above are generally similar to those of the southern part of the stable Ordos Basin, except for the smaller crust thickness. This indicates the presence of differences in Mesozoic destruction between the southern and northern zones in the eastern part of the North China Craton. The northern zone was subjected to significant destruction, while the southern zone was subjected to modifications, primarily in the form of local changes in the structures and/ or properties of the crust or lithospheric mantle, with the overall structure and stability of the craton kept intact. The formation of high-quality source rock is primarily influenced by the abnormal flourishment of organisms in water bodies during the syndepositional period, and is also strongly associated with the high geothermal setting of basins and nutrients from hydrothermal solutions and volcanoes. In other words, it is mainly controlled by deep processes and deep-major fault activity. The differences in the deep structures and modern and paleo geothermal fields of the two basins correspond to the difference in richness of oil resources, suggesting that there is an important internal or causal relationship between the two aspects. This viewpoint coincides with the conditions and environments required for the development of high-quality source rock in hydrocarbon-rich basins (sags) in China and other countries, and is evidenced by the modern lake basin of the East African Rift. A new hydrocarbon generation model is proposed in this work: petroleum is a comprehensive product of the integration of bioenergy, thermal energy, and other related energies (such as chemical and kinetic energy) and their interactions; the degree of richness of petroleum is generally controlled by the regional tectonic structure, thermal environment, and deep processes; nonmarine basins or depressions with abundant resources are closely related to active deep processes, intense exchange of material between the deep and shallow layers, participation of external hydrocarbons, and energy integration and conversion.Liu, C., Li, Z., Berhe, A.A., Zeng, G., Xiao, H., Liu, L., Wang, D., Peng, H., 2019. Chemical characterization and source identification of organic matter in eroded sediments: Role of land use and erosion intensity. Chemical Geology 506, 97-112. erosion is a key variable in the biogeochemical cycle of carbon (C) on the Earth's surface. However, questions remain about the roles of land use and erosion intensity on the composition, source, and fate of soil C eroded from terrestrial to fluvial systems. In this study, chemical characteristics of eroded water-extractable organic matter (WEOM) in soils and sediments, as well as subsequent source identification, were inferred from UV–Visible absorption and fluorescence excitation emission matrix (EEM)-parallel factor analysis (PARAFAC) in study sites that include land uses and gully banks, experiencing three levels of erosion intensity in a semi-arid region of China. 13C and 15N isotopic signatures along with elemental ratios were also successfully employed to explore the source of bulk soil organic matter (SOM) in sediments. We found a much greater contribution of condensed aromatic structures and hydrophobic fraction of soluble organic compounds in forest soils compared to croplands at eroding sites, where these variables were greater than those of depositional sites. The results from fluorescence analysis in soil materials showed that erosion intensity has a negligible influence on WEOM quality. The EEM-PARAFAC with fluorescence indices indicated that biological production of soil substrates can also play a key role in the dynamics of WEOM induced by soil erosion. Our results from an isotopic mixing model analysis showed that gully bank soil was the primary sources of sedimentary SOM in all regions with different erosion intensities (mean probability estimate (MPE) 100% for the region with light erosion intensity, 36.18% for the region with high erosion intensity, and 99.25% for the region with extremely high erosion intensity). However, orchard and grassland were also the main contributors for the SOM in sediments in regions with high erosion intensity, accounting for MPE 29.93% and 33.89%, respectively. Our findings demonstrate that land use and erosion intensity have significant effect on nature of eroded OM.Liu, H., Yu, B., Xie, Z., Han, S., Shen, Z., Bai, C., 2018. Characteristics and implications of micro-lithofacies in lacustrine-basin organic-rich shale: a case study of Jiyang depression, Bohai Bay Basin. Acta Petrolei Sinica 39, 1328-1343. oil is an important component of unconventional hydrocarbon resources, and is also a hot spot in research of petroleum geology. In China, shale oil resources massively occur in the continental lacustrine basin. Due to the differences between shale oil and conventional oil in reserving, sealing, trapping and migration, the lithofacies have a significant controlling effect on shale oil accumulation. This study focuses on organic-rich shale in the lower sub-member of Member 3 to upper sub-member of Member 4 of Shahejie Formation in Jiyang depression, Bohai Bay Basin. Based on the petrology, whole-rock X-ray diffraction (XRD), total organic carbon (TOC) content and direct hydrocarbon indication (DHI) of the study layers, it is indicated that the micro-lithofacies of shale layers are dominated by thin lenticle crystalline limestone micro-lithofacies (LF1), lamellar micritic limestone micro-lithofacies (LF2), thick massive lime mudstone micro-lithofacies (LF3), massive mudstone micro-lithofacies (LF4)and black shale micro-lithofacies (LF5). Among them, the favorable micro-lithofacies (or combination)for shale oil accumulation are LF5, LF4 and LF1+LF5. There are two shale oil accumulation models in Jiyang depression:one is the "self-generation and self-reservoir" model dominated by LF4 and LF5; the other is the "crystalline limestone reservoir" model dominated by LF1+LF5. The crystalline limestones are more beneficial to shale oil accumulation, development and production, and the LF1+LF5 is the "sweet spot" micro-lithofacies combination for continental shale oil exploration and development in Jiyang depression.Liu, J., Zhang, Y., Hu, Z., Li, Y., Yang, X., 2018. An experimental study on the mass transfer mechanism and the flow regime of gas in nano-scale pores of shale gas reservoirs. Natural Gas Industry B 38, 87-95. order to explore the mass transfer mode and mechanism and the flow regime of gas in nano-scale pores of shale gas reservoirs and to develop a method for expressing the apparent permeability of shale reasonably, it is necessary to comprehensively analyze the mass transfer mechanism of gas in nano-scale pores of shale gas reservoirs from microscopic and macroscopic perspectives based on previous research results. After gas seepage in tight shale was experimentally studied, the real flow regime of gas in nano-scale pores was analyzed, and the effects of pore size, pressure and other parameters on shale permeability were discussed. Finally, the reasonable expression method of apparent permeability was discussed by comparing different apparent permeability models. And the following research results were obtained. First, the mass transfer mode of free gas in nano-scale pores of shale gas reservoirs is mainly slippage flow, Knudsen diffusion and Fick diffusion, and that of adsorbed gas is mainly surface diffusion. The flow regime of gas is slippage flow or transitional flow without continuous flow. Besides, the smaller the pores and the lower the pressure, the weaker the slippage flow and the stronger the Knudsen diffusion. Second, under the same experimental conditions, the Darcy permeability is the lowest, the Klinkenberg apparent permeability is the medium, and both APF and Wu apparent permeability are the highest. Their curves of APF and Wu apparent permeability alternate. The Beskok–Karniadakis (B–K) apparent permeability and the Civan apparent permeability are very close. Third, in the model of Wu apparent permeability, the slippage flow is the main mass transfer mode of gas in the slippage and transition zones. Fourth, in the model of APF apparent permeability, the slippage flow is the main mass transfer mode of gas in the slippage zone while Knudsen diffusion is the main mass transfer mode in the transition zone.Liu, K., Wang, L., Ostadhassan, M., Zou, J., Bubach, B., Rezaee, R., 2019. Nanopore structure comparison between shale oil and shale gas: examples from the Bakken and Longmaxi Formations. Petroleum Science 16, 77-93. order to analyze and compare the differences in pore structures between shale gas and shale oil formations, a few samples from the Longmaxi and Bakken Formations were collected and studied using X-ray diffraction, LECO TOC measurement, gas adsorption and field-emission scanning electron microscope. The results show that samples from the Bakken Formation have a higher TOC than those from the Longmaxi Formation. The Longmaxi Formation has higher micropore volume and larger micropore surface area and exhibited a smaller average distribution of microsize pores compared to the Bakken Formation. Both formations have similar meso-macropore volume. The Longmaxi Formation has a much larger meso-macropore surface area, which is corresponding to a smaller average meso-macropore size. CO2 adsorption data processing shows that the pore size of the majority of the micropores in the samples from the Longmaxi Formation is less than 1?nm, while the pore size of the most of the micropores in the samples from the Bakken Formation is larger than 1?nm. Both formations have the same number of pore clusters in the 2–20 nm range, but the Bakken Formation has two additional pore size groups with mean pore size diameters larger than 20?nm. Multifractal analysis of pore size distribution curves that was derived from gas adsorption indicates that the samples from the Longmaxi Formation have more significant micropore heterogeneity and less meso-macropore heterogeneity. Abundant micropores as well as meso-macropores exist in the organic matter in the Longmaxi Formation, while the organic matter of the Bakken Formation hosts mainly micropores.Liu, P., Wang, X., Horita, J., Fang, X., Zheng, J., Li, X., Meng, Q., 2019. Evaluation of total organic carbon contents in carbonate source rocks by modified acid treatment method and the geological significance of acid-soluble organic matters. Energy Exploration & Exploitation 37, 219-229. organic carbon contents are an important parameter in evaluating hydrocarbon source rocks and it shows the hydrocarbon-generating potential of hydrocarbon source rocks. In this study, the total organic carbon of 16 carbonate rocks with different maturity level was determined by a modified acid treatment protocol of the elemental analyzer method. In the modified method, montmorillonite is used to thicken the residue of acid treatment and remaining acid solution. Then, total organic carbon values of “clay-paste” sample were analyzed by the element analysis method. The results of 16 carbonate rocks show that the total organic carbon values with the new method were greater than the conventional total organic carbon test in a majority of the samples. Additionally, the fraction of acid-soluble organic matters was investigated and it shows no clear relationship of the fraction of acid-soluble organic matters with maturity and total organic carbon values in source rocks. Hence, it indicates that the released acid-soluble organic matters are characterized by complex factors that influence their occurrence and compositions.Liu, Q., Wu, X., Wang, X., Jin, Z., Zhu, D., Meng, Q., Huang, S., Liu, J., Fu, Q., 2019. Carbon and hydrogen isotopes of methane, ethane, and propane: A review of genetic identification of natural gas. Earth-Science Reviews 190, 247-272. genetic identification of different types of natural gas is notably important for assessment of its sources and exploration potential. The chemical and isotopic (C and H, in particular) compositions of natural gas vary significantly due to the complexity of its generation, migration, and accumulation processes. The “coal-type” gas generated from humic matter is generally enriched in 13C as compared to "oil-type" gas generated from sapropelic organic matter. However, gas originating from fresh-brackish water environments is depleted in 13C whereas gas from saline environments is enriched in 13C. Notwithstanding organic precusors and sedimentary environments, both isotope compositions of alkanes tend to become enriched both in 13C and 2H with prograde thermal evolution. Therefore, in addition to thermal maturity, source material is the major controlling factor of carbon isotope compositions, whereas sedimentary environment is predominant in governing hydrogen isotopes. Secondary processes, including thermochemical sulfate reduction (TSR) and diffusion, result in an enrichment of the gases in 13C and 2H due to mass-dependent kinetic isotope effect. Microbial degradation causes a decrease in propane content and an enrichment in 12C and 2H of the residual propane. The abiogenic gases may include methane from deep mantle and high molecular weight hydrocarbons through Fischer-Tropsch type (FTT) synthesis. Methane of mantle origin possesses a narrow range of isotope compositions, although it is still a tall task to determine the exact values. In contrast, isotopes of alkane gases synthesized from FTT processes are in a wide range. In sedimentary basins, the mixing of gases from multiple sources and/or through different secondary processes may pose a challenage to identification of their origins. The detailed assessment is provided here with case studies from major oil and gas basins in China. This review provides identification of misconceptions in genetic types of natural gas using carbon and hydrogen isotopes of alkanes, and sheds insights into using isotope geochemistry as an important diagnostic tool for energy exploration as well.Liu, X., Fike, D., Li, A., Dong, J., Xu, F., Zhuang, G., Rendle-Bühring, R., Wan, S., 2019. Pyrite sulfur isotopes constrained by sedimentation rates: Evidence from sediments on the East China Sea inner shelf since the late Pleistocene. Chemical Geology 505, 66-75. compositions of coeval sulfide and sulfate have been widely employed to reconstruct the seawater chemistry evolution over geologic time; however, these signals can be modulated by other factors, such as the sedimentation rate. Here, we present a data set of pyrite sulfur isotopes (δ34Spy) derived from 60-m drilled core sediments deposited on the inner shelf of the East China Sea since 16.5?ka. The resulting δ34Spy values range from ?38.2 to 15.0‰ (Vienna Canyon Diablo Troilite; V-CDT), representing a range of 53.2‰. Freshwater deposition before 12.3?ka produced a limited pyrite abundance and δ34Spy values that fall within the typical range of freshwater environments. After the marine incursion in the study area at 12.3?ka, variations in the δ34Spy values become significantly correlated with sedimentation rates (SRs; r?=?0.78, p?<?0.01), which were controlled by the intensity of coastal currents in response to the East Asian winter monsoon. Specifically, pyrite sulfur is markedly depleted in 34S during the intervals with low SRs (δ34Spy?<??30‰) relative to that observed during the intervals with high SRs (δ34Spy?>?0‰), suggesting that SRs exert controls on δ34Spy values. We propose that these sedimentary controls are expressed by modulating the connectivity between porewaters and the overlying seawater. Low SRs tend to form an open diagenetic system, in which the pyrites are able to preserve the large biological fractionations associated with microbial sulfate reduction (and disproportionation). In contrast, high SRs favour a restricted diagenetic system, in which the distillation of porewater sulfate produces pyrites enriched in 34S, masking the magnitude of biological fractionation during microbial sulfur cycling. These findings highlight the critical effect of the local sedimentation regime on pyrite sulfur isotopic compositions, especially within shallow depositional environments, over geologic time.Liu, X., Gong, Y., Xiong, W., Cui, L., Hu, K., Che, Y., Zhao, J., 2019. Highly selective detection of benzene, toluene, and xylene hydrocarbons using coassembled microsheets with F?rster resonance energy transfer-enhanced photostability. Analytical Chemistry 91, 768-771. BTX hydrocarbons (benzene, toluene, and xylene) are highly toxic and/or carcinogenic, the sensitive and selective detection of BTX has attracted considerable attention in environmental monitoring and human health.(1?17) As a simple, portable, and highly sensitive detection technology among various detection technologies, fluorescence sensors or sensor arrays have been widely applied in the identification of hazardous chemicals.(1,2,14?21) However, because of lacking of active chemical function group(s), BTX hydrocarbons, particularly at low concentrations (at the subppm level), are difficult be detected by most reported fluorescent sensors. Different degrees of swelling of materials by BTX to generate fluorescence responses constitute a general detection mechanism for reported fluorescence sensors.(1,2,14?17) Nonetheless, this method requires exposure to BTX at high concentrations that constrains its practical application. Therefore, developing novel fluorescence detection methods with enhanced sensitivity is needed. In addition, photobleaching is a common but disfavorable photochemical process for fluorescence sensor, which causes fluorescence loss and reduces the service life of sensors. Although various physical and chemical methods have been employed to reduce photobleaching, these methods either complicate device fabrication and materials synthesis or compromise the sensing performance. Therefore, developing the photostable fluorescence sensors or sensor arrays while maintaining high sensitivity and selectivity for BTX is highly desirable but remains challenging.In this work, we report the fabrication of highly photostable and fluorescent microsheets coassembled from molecules 1 and 2 (Figure 1) for sensitive and selective detection of BTX. We demonstrate that F?rster resonance energy transfer (FRET) within the resulting coassembled microsheets yields the high photostability because the fast excitation energy transfer from nonphotostable 1 to photostable 2 avoids the photoreaction of 1 with oxygen. Importantly, the combined features of 1 and 2 allow 1–2 coassembled microsheets to give fluorescence responses to BTX distinct from most other VOC vapors (except diethyl ether, butyl acetate, and n-hexane). By integrating two coassembled microsheets with the molar ratio of 1 to 2 at 1:1 and 5:1 into a two-component array, the selectivity for BTX detection against diethyl ether, butyl acetate, and n-hexane can be further achieved.Liu, X., Wang, X., Bu, J., Zhou, X., Zheng, O., 2019. Tandem analysis by a dual-trap miniature mass spectrometer. Analytical Chemistry 91, 1391-1398. mass spectrometers are of an increasing interest for in-situ analyses, and their coupling with the ambient ionization sources is a valid path for direct analysis of complex samples. In this study, a miniature mass spectrometer using discontinuous atmospheric pressure interface was developed with a dual-LIT (linear ion trap) configuration. The comprehensive scan modes were enabled for tandem mass spectrometry analysis, which are critical for high-quality qualitative and quantitative analysis. A real-time pressure control was implemented to facilitate the ion transfer and collision induced dissociation (CID). Beam-type CID could be performed for tandem analysis at a high number of stages. In-trap CID at high q could also be performed with the fragment ions accumulated in a second trap. A precursor ion scan mode for analyzing target analytes has also been demonstrated.Liu, Y., Li, X., Zeng, Z., Yu, H.-M., Huang, F., Felis, T., Shen, C.-C., 2019. Annually-resolved coral skeletal δ138/134Ba records: A new proxy for oceanic Ba cycling. Geochimica et Cosmochimica Acta 247, 27-39. ratios in the skeletons of scleractinian shallow-water corals have been used as proxies for coastal and oceanic processes such as river discharge, oceanic upwelling and surface ocean productivity. However, the variations in Ba/Ca ratios in aragonitic coral skeletons remain difficult to interpret as an environmental proxy. This difficulty is mainly due to the influence of internal (biomineralization) and multiple external (environmental) processes on Ba incorporation into coral skeletons, and these processes are hard to constrain with Ba/Ca alone. Here we present the first annually-resolved records of the Ba isotopic compositions (δ138/134Ba) in shallow-water corals (Porites) collected alive in the field, supplemented by the analysis of Ba/Ca ratios. Seven coral cores were recovered at different oceanic settings in the South China Sea, extending from the northern inner shelf to the central and southern deep basin. The annual δ138/134Ba records of six corals fell within a narrow range from 0.24?±?0.03‰ to 0.38?±?0. 03‰ (2SD), with a mean value of 0.33?±?0.08‰ (2SD, N?=?21). One single inner-shelf coral revealed low δ138/134Ba values (0.10?～?0.11?±?0.03‰), which might reflect the influence of terrestrial water/sediment. In contrast, the coral Ba/Ca ratios showed a wide range of intercolony differences, from 2 to 14?μmol/mol. This variation is too large to be ascribed to the changes in the Ba concentrations of seawater or other environmental parameters. Rayleigh fractionation between corals and seawater during biomineralization was proposed to explain the anomalous variations in the Ba/Ca ratios observed in coral skeletons. However, this result is incompatible with the relatively constant Ba isotopic compositions in coral. Instead, we suggest that the probable precipitation of witherite (BaCO3) within the domains of aragonite under oversaturated calcifying fluid could explain the large variability in the coral Ba/Ca ratios. The coral δ138/134Ba records from diverse oceanic settings were largely unaffected by biomineralization processes and temperature and displayed a relatively constant negative offset from typical surface seawaters. Our results suggest that Ba isotopes in Porites could be a proxy for reconstructing the δ138/134Ba of seawater and hence provide new insights into Ba cycling in the upper oceans in the past.Liuzzi, G., Villanueva, G.L., Mumma, M.J., Smith, M.D., Daerden, F., Ristic, B., Thomas, I., Vandaele, A.C., Patel, M.R., Lopez-Moreno, J.-J., Bellucci, G., 2019. Methane on Mars: New insights into the sensitivity of CH4 with the NOMAD/ExoMars spectrometer through its first in-flight calibration. Icarus 321, 671-690. Nadir and Occultation for MArs Discovery instrument (NOMAD), onboard the ExoMars Trace Gas Orbiter (TGO) spacecraft was conceived to observe Mars in solar occultation, nadir, and limb geometries, and will be able to produce an outstanding amount of diverse data, mostly focused on properties of the atmosphere. The infrared channels of the instrument operate by combining an echelle grating spectrometer with an Acousto-Optical Tunable Filter (AOTF). Using in-flight data, we characterized the instrument performance and parameterized its calibration. In particular: an accurate frequency calibration was achieved, together with its variability due to thermal effects on the grating. The AOTF properties and transfer function were also quantified, and we developed and tested a realistic method to compute the spectral continuum transmitted through the coupled grating and AOTF system. The calibration results enabled unprecedented insights into the important problem of the sensitivity of NOMAD to methane abundances in the atmosphere. We also deeply characterized its performance under realistic conditions of varying aerosol abundances, diverse albedos and changing illumination conditions as foreseen over the nominal mission. The results show that, in low aerosol conditions, NOMAD single spectrum, 1σ sensitivity to CH4 is around 0.33?ppbv at 20?km of altitude when performing solar occultations, and better than 1?ppbv below 30?km. In dusty conditions, we show that the sensitivity drops to 0 below 10?km. In Nadir geometry, results demonstrate that NOMAD will be able to produce seasonal maps of CH4 with a sensitivity around 5 ppbv over most of planet's surface with spatial integration over 5?×?5° bins. Results show also that such numbers can be improved by a factor of ~10 to ~30 by data binning. Overall, our results quantify NOMAD's capability to address the variable aspects of Martian climate.Llompart, M., Celeiro, M., García-Jares, C., Dagnac, T., 2019. Environmental applications of solid-phase microextraction. TrAC Trends in Analytical Chemistry 112, 1-12. microextraction is a well-established green solvent free extraction technique with a large number of applications in different fields such as food, forensic, biomedical, and the environment. The present review comprehensively describes the most recent applications mostly reported from 2013 of SPME for the extraction of environmental pollutants including persistent organic pollutants (POPs), pesticides, and emerging pollutants such as pharmaceuticals and personal care products (PPCPs), in different environmental matrices. This review also covers the last technological developments including the use of novel extraction coatings (MOFs, CNTs, ILs), formats (e.g. TFSE), approaches (e.g. vacuum, cold fiber, and in-tube SPME), and on-site devices. The hyphenation of SPME with other techniques, especially mass spectrometry will be described, as well. The usefulness of SPME to follow (photo)degradation studies, both in target and non-target analysis, as well as to determine some of the physicochemical parameters governing the pollutant fate in the environment is also illustrated through different examples.Lomax, B.H., Lake, J.A., Leng, M.J., Jardine, P.E., 2019. An experimental evaluation of the use of Δ13C as a proxy for palaeoatmospheric CO2. Geochimica et Cosmochimica Acta 247, 162-174. changes in atmospheric CO2 over geological time via the development of well constrained and tested proxies is of increasing importance within the Earth sciences. Recently a new proxy (identified as the C3 proxy) has been proposed that is based on the relationship between CO2 and carbon isotope discrimination (Δ13C) of plant leaf tissue. Initial work suggests that this proxy has the capacity to deliver accurate and potentially precise palaeo-CO2 reconstructions through geological time since the origins of vascular plants (～450?Mya). However, the proposed model has yet to be fully validated through independent experiments. Using the model plant Arabidopsis thaliana exposed to different watering regimes and grown over a wide range of CO2 concentrations (380, 400, 760, 1000, 1200, 1500, 2000 and 3000?ppm) relevant to plant evolution we provide an experimental framework that allows for such validation. Our experiments show that a wide variation in Δ13C as a function of water availability is independent of CO2 treatment. Validation of the C3 proxy was undertaken by comparing growth CO2 to estimates of CO2 derived from Δ13C. Our results show significant differences between predicted and observed CO2 across all CO2 treatments and water availabilities, with a strong under prediction of CO2 in experiments designed to simulate Cenozoic and Mesozoic atmospheric conditions (≥1500?ppm). Further assessment of Δ13C to predict CO2 was undertaken using Monte Carlo error propagation. This suite of analysis revealed a lack of convergence between predicted and observed CO2. Collectively these findings suggest that the relationship between Δ13C and CO2 is poorly constrained. Consequently the use of Δ13C as a proxy to reconstruct palaeoatmospheric CO2 is of limited use as the estimates of CO2 are not accurate when compared to known growth conditions.Long, Z., Zhan, Z., Guo, Z., Li, Y., Yao, J., Ji, F., Li, C., Zheng, X., Ren, B., Huang, T., 2019. A novel two-dimensional liquid chromatography - Mass spectrometry method for direct drug impurity identification from HPLC eluent containing ion-pairing reagent in mobile phases. Analytica Chimica Acta 1049, 105-114. this study, a novel two dimensional liquid chromatography – mass spectrometry (2D-LC-MS) method with use of a weak anion exchange column between the 1st DLC RP column and the 2nd DLC RP column (RP1-WAX-RP2) was developed and applied to identify drug impurities from MS incompatible mobile phases containing sodium 1-octanesulfonate and non-volatile buffer. The 1st DLC conditions follow exactly the original standard HPLC method recorded in Chinese Pharmacopeia (ChP), European Pharmacopeia (EP) or US Pharmacopeia (USP). An impurity fraction was collected with a built-in sample loop (100?μL) and transferred to the WAX column where 1-octanesulfonate and phosphate were trapped and removed. While, the impurity and other cations were eluted to the 2nd D column (RP2) for separation and identification by connected IT-TOF MS. Methods were programmed and applied to identify impurities in two generic drugs, sulpiride (hydrophilic drug with logP 0.57) and dobutamine (hydrophobic drug with logP 3.6). The results indicate that the methods based on RP1-WAX-RP2 column configuration offer a feasible solution for direct impurity identification in generic drug product or API without needs of off-line desalting from the MS incompatible mobile phases containing ion-pairing reagent and non-volatile buffer.Loron, C.C., Rainbird, R.H., Turner, E.C., Greenman, J.W., Javaux, E.J., 2019. Organic-walled microfossils from the late Mesoproterozoic to early Neoproterozoic lower Shaler Supergroup (Arctic Canada): Diversity and biostratigraphic significance. Precambrian Research 321, 349-374. diversification of acritarchs (organic-walled vesicular microfossils of unknown affinity), filamentous, and multicellular microorganisms, happened during a time of profound environmental, biological, and ecological change. The Mesoproterozoic to Neoproterozoic transition is a key interval, notably for eukaryotic organisms. New assemblages of organic-walled microfossils from the ca. 1230?Ma to 900?Ma lower Shaler Supergroup of Arctic Canada record an impressive diversity, including macroscopic compressions of Chuaria circularis and numerous unambiguous eukaryotic taxa. The index taxon Trachyhystrichosphaera aimika co-occurs with eukaryotic taxa hitherto reported only from earlier (Dictyosphaera, Gigantosphaeridium, Satka favosa – sensu Javaux and Knoll, 2016) or later (Microlepidopalla) time intervals. Five new taxa, comprising the spheroidal acritarchs with inner wall sculpture Nunatsiaquus cryptotorus n. gen., n. sp. and Daedalosphaera digitisigna n. gen., n. sp.; the acanthomorphs (spiny acritarchs) with regularly distributed processes Herisphaera arbovela n. gen., n. sp. and Herisphaera triangula n. sp.; and the process-bearing multicellular Ourasphaira giraldae n. gen., n. sp.; are reported, along with three unnamed forms. Collectively, these remarkable microfossils (63 taxa, including 25 eukaryotic forms) demonstrate the greatest diversity of eukaryotes ever recorded for this time interval.Lübeck, J.S., Tomasi, G., Poulsen, K.G., Mante, O.D., Dayton, D.C., Verdier, S., Christensen, J.H., 2018. Nontarget analysis of oxygenates in catalytic fast pyrolysis biocrudes by supercritical fluid chromatography high-resolution mass spectrometry. Energy & Fuels 33, 296-306. fast pyrolysis (CFP) biocrudes can comprise up to 30 wt % of oxygen content in compounds such as polyphenols, acids, carbonyls, and anhydrosugars and thus require upgrading by, e.g., hydrotreatment, to produce transport fuels. The chemical characterization of phenolic and acidic compounds in biocrudes is of great importance to optimize the CFP process. In this study, an analytical workflow is proposed for nontarget chemical fingerprinting analysis of CFP biocrudes using supercritical fluid chromatography high-resolution mass spectrometry (SFC-HRMS) with negative electrospray ionization (ESI–), followed by multivariate data analysis. The method was developed and tested on five biocrude samples from loblolly pine (Pinus taeda) with varying oxygen content (14.9–28.8 wt % wet basis) due to different CFP conditions. The pixel-based analysis displayed chemical variation between all samples. Twenty-four regions of interest were tentatively identified, including mono- and polyphenols, fatty acids, and methylated and methoxylated phenols. The identification workflow and MS/MS analysis were prioritized on the peaks with the highest relative concentration. The developed SFC-ESI–-HRMS method shows high repeatability and analyzed oxygen-containing compounds with hydroxyl and/or carboxyl moieties in combination with other moieties of up to 400 Da.Luchinina, V.A., 2018. Cambrian photosynthetic and chemosynthetic ecosystems in the Siberian Craton. Paleontological Journal 52, 1126-1130. leading role of bacterial communities in the formation of marine sedimentary rocks is inferred from the synthesis of expert knowledge about bacterial paleontology, while the results of oceanic studies (materials and data) offer new insights into symbiotic relationships between phototrophic and chemotrophic bacteria and fauna.Lüdecke, T., Kullmer, O., Wacker, U., Sandrock, O., Fiebig, J., Schrenk, F., Mulch, A., 2018. Dietary versatility of Early Pleistocene hominins. Proceedings of the National Academy of Sciences 115, 13330-13335.: Clumped and stable isotope data of paleosol carbonate and fossil tooth enamel inform about paleoenvironments of Early Pleistocene hominins. Data on woodland- vs. grassland-dominated ecosystems, soil temperatures, aridity, and the diet of Homo rudolfensis and Paranthropus boisei ca. 2.4 Ma show that they were adapted to C3 resources in wooded savanna environments in relatively cool and wet climates in the Malawi Rift. In contrast, time-equivalent Paranthropus living in open and drier settings in the northern East African Rift relied on C4 plants, a trend that became enhanced after 2 Ma, while southern African Paranthropus persistently relied mainly on C3 resources. In its early evolutionary history, Homo already showed a high versatility, suggesting that Pleistocene Homo and Paranthropus were already dietary generalists.Abstract: New geochemical data from the Malawi Rift (Chiwondo Beds, Karonga Basin) fill a major spatial gap in our knowledge of hominin adaptations on a continental scale. Oxygen (δ18O), carbon (δ13C), and clumped (Δ47) isotope data on paleosols, hominins, and selected fauna elucidate an unexpected diversity in the Pleistocene hominin diet in the various habitats of the East African Rift System (EARS). Food sources of early Homo and Paranthropus thriving in relatively cool and wet wooded savanna ecosystems along the western shore of paleolake Malawi contained a large fraction of C3 plant material. Complementary water consumption reconstructions suggest that ca. 2.4 Ma, early Homo (Homo rudolfensis) and Paranthropus (Paranthropus boisei) remained rather stationary near freshwater sources along the lake margins. Time-equivalent Paranthropus aethiopicus from the Eastern Rift further north in the EARS consumed a higher fraction of C4 resources, an adaptation that grew more pronounced with increasing openness of the savanna setting after 2 Ma, while Homo maintained a high versatility. However, southern African Paranthropus robustus had, similar to the Malawi Rift individuals, C3-dominated feeding strategies throughout the Early Pleistocene. Collectively, the stable isotope and faunal data presented here document that early Homo and Paranthropus were dietary opportunists and able to cope with a wide range of paleohabitats, which clearly demonstrates their high behavioral flexibility in the African Early Pleistocene.Luo, S., Lutkenhaus, J.L., Nasrabadi, H., 2019. Experimental study of pore size distribution effect on phase transitions of hydrocarbons in nanoporous media. Fluid Phase Equilibria 487, 8-15. phase behavior of a fluid in a nanoporous system is altered from that in the bulk due to confinement effects. There have been many experimental studies on this important effect, yet the vast majority are limited to porous media with a narrow or singular pore size distribution. However, natural porous media exhibit a broad pore size distribution. For example, in shale rocks the pore size ranges from several nanometers to hundreds of nanometers. It is not clear if a broad pore size distribution has a significant effect on the phase transition of nanoconfined fluids, and, if effects are present, how and why the phase behavior is altered. The effects of a distributed pore size on the bubble point of confined fluids as measured by differential scanning calorimetry (DSC) are not known. Here, we present an experimental study on the effect of pore size distribution on the liquid-vapor phase transition of n-hexane, n-octane and n-decane confined in nonporous media. We report a method to discretize the pore size distribution of natural shale rocks so that it can be mimicked using mixtures of synthetic nanoporous media. Using DSC, we show that the presence of a broad pore size distribution significantly alters the vapor-liquid phase transition of confined hydrocarbons. In fully saturated (i.e. filled) nanoporous media, the largest pore size dictates the onset of liquid-vapor phase transition (.i.e. bubblepoint). However, when the porous media is partially saturated, smaller pore sizes influence the bubblepoint. These findings suggest that there is a dependency of the confined fluid phase behavior on the fluid saturation in nanoporous media with a broad pore size distribution, which contributes to a broader understanding of phase transitions in natural porous media.Luo, X., Ren, X., Wang, S., 2019. Supercritical CO2-water-shale interactions and their effects on element mobilization and shale pore structure during stimulation. International Journal of Coal Geology 202, 109-127. are many advantages to using supercritical carbon dioxide (ScCO2) fracturing technology to exploit shale gas reservoirs in China, including minimal damage to the environment or formation, and displacing methane (CH4) in the adsorbed state. When ScCO2 enters fractures in the formation, ScCO2-water-shale interactions may affect the physicochemical properties of shale. In this study, a high-pressure reaction system was adopted to simulate ScCO2-water-shale interactions under ScCO2 stimulation conditions. The element mobilization and pore structure before and after the reaction were measured using ICP-MS, XRF. The results show that the major elements, including Ca, Mg, Na, K, and Al, exhibit varying degrees of mobilization after the interactions because of dissolution of carbonate and silicate minerals in shale samples. Compared with the major elements, trace elements have a lower mobility, quantified as <13.97%. The specific surface areas and pore volumes of two shale samples increase at different degrees after the reaction. The interactions have a more significant influence on the micropores. In addition, fractal features of the shale pore structure were analyzed. The fractal dimensions of the shale samples increase after the reaction, indicating that pore surface roughness increases, and pore structure morphology gradually transforms from regular to complex.Lutzoni, F., Nowak, M.D., Alfaro, M.E., Reeb, V., Miadlikowska, J., Krug, M., Arnold, A.E., Lewis, L.A., Swofford, D.L., Hibbett, D., Hilu, K., James, T.Y., Quandt, D., Magallón, S., 2018. Contemporaneous radiations of fungi and plants linked to symbiosis. Nature Communications 9, Article 5451. between fungi and plants, including parasitism, mutualism, and saprotrophy, have been invoked as key to their respective macroevolutionary success. Here we evaluate the origins of plant-fungal symbioses and saprotrophy using a time-calibrated phylogenetic framework that reveals linked and drastic shifts in diversification rates of each kingdom. Fungal colonization of land was associated with at least two origins of terrestrial green algae and preceded embryophytes (as evidenced by losses of fungal flagellum, ca. 720?Ma), likely facilitating terrestriality through endomycorrhizal and possibly endophytic symbioses. The largest radiation of fungi (Leotiomyceta), the origin of arbuscular mycorrhizae, and the diversification of extant embryophytes occurred ca. 480?Ma. This was followed by the origin of extant lichens. Saprotrophic mushrooms diversified in the Late Paleozoic as forests of seed plants started to dominate the landscape. The subsequent diversification and explosive radiation of Agaricomycetes, and eventually of ectomycorrhizal mushrooms, were associated with the evolution of Pinaceae in the Mesozoic, and establishment of angiosperm-dominated biomes in the Cretaceous.Maaleki-Moghadam, M., Rafiei, B., Richoz, S., Woods, A.D., Krystyn, L., 2019. Anachronistic facies and carbon isotopes during the end-Permian biocrisis: Evidence from the mid-Tethys (Kisejin, Iran). Palaeogeography, Palaeoclimatology, Palaeoecology 516, 364-383. Permian mass extinction (LPME) research has focused primarily on Tethyan sections because it is believed that these successions are more complete than those from other localities, and provide a more comprehensive record of the largest, most devastating extinction event in Earth history. The Kisejin section, a previously undocumented mid-Tethyan, Upper Permian-Lower Triassic succession located in the Central-Iran Plate. The Kisejin section contains a continuous Permian-Triassic sequence with only small breaks in sedimentation and was examined in order to determine sedimentologic, biostratigraphic, and carbon isotopic trends across the Permian-Triassic transition. Abnormal (anachronistic) carbonates developed in the study area following the LPME, and include microbialites, edgewise conglomerates, sparitic microspheres, and microbially-coated grains; microbialites occur as thrombolites, stromatolites, and as agglutinated forms. Renalcis-type calcimicrobes are documented for the first time from Permian-Triassic boundary microbialites (PTBMs) of Iran. Coated grains fall into two groups, and include pre-PTBM ooids, which are dense and cloudy, and possibly microbial in origin, and post-PTBM cortoids with destructive and constructive micrite envelopes. Latest Permian conodonts (H. praeparvus, M. ultima), coupled with carbon isotopic values, place the Permian-Triassic boundary within the lowermost thrombolite unit, about 2.1?m above the boundary between the Nessen Formation and the Elika Formation, and indicate that microbialite growth began during the latest Permian. Our study of this previously unknown section shows that, unlike other well-known PTB sections from Iran, the microbialite pattern is complicated, and is more similar to PTBM successions from Turkey. In addition, we note a similarity between the unusual facies of the Kisejin section and those of eastern Tethyan sections from China (i.e. sparry microspheres and Renalcis-type calcimicrobes); these unusual facies have not been previously reported from other well-known Iranian sections, including Julfa and Abadeh, which are thick and have been extensively studied.Madof, A.S., Bertoni, C., Lofi, J., 2019. Discovery of vast fluvial deposits provides evidence for drawdown during the late Miocene Messinian salinity crisis. Geology 47, 171-174. late Miocene Messinian salinity crisis (MSC) was a significant oceanographic event that caused widespread evaporitic accumulation throughout the Mediterranean Basin. Although multiple hypotheses exist regarding the origin of evaporitic and post-evaporitic deposits, researchers remain divided on the magnitude of base-level fall, and on whether these accumulations record deep-water or non-marine conditions. Here, we introduce a previously unknown, upper Messinian fluvial deposit comparable in size to the late Miocene Nile River fluvial valley fill and show that near-complete desiccation of the eastern Mediterranean was responsible for its development. The basin-wide accumulation, which is located offshore Cyprus, Syria, Lebanon, and Israel, lies directly atop deep-basin evaporites and related erosional surfaces, and is one of the largest known riverine deposits associated with the terminal MSC. From marked onshore incision and basinward thinning trends, the source of the accumulation is presumed to be a formerly unidentified drainage basin in southern Turkey and western Syria; the deposit extends >500 km into the western Levant Basin, where its depositional sink is marked by six well-developed backstepping lobes. Based on the deposit’s seismic stratigraphy and morphology, which provide clear evidence of subaerial exposure, we question current hypotheses proposing a deep-water origin for late Messinian accumulations. We also draw specific attention to the development of extensive circum-Mediterranean non-marine conditions prior to Zanclean marine transgression, and to the previously overlooked role of fluvial systems in diluting hypersaline lakes in evaporitic basins.Mahaney, W.C., Somelar, P., West, A., Dirszowsky, R.W., Allen, C.C.R., Remmel, T.K., Tricart, P., 2019. Reconnaissance of the Hannibalic route in the Upper Po Valley, Italy: Correlation with biostratigraphic historical archaeological evidence in the Upper Guil Valley, France. Archaeometry 61, 242-258. over the alpine route taken by the Hannibalic Army from the Rh?ne Basin into Italia in 218 bc (2168?cal bp) has raged amongst classicists for over two millennia. Because Hannibal crossed the Alps, the significance for identifying the route taken by the Punic Army lies more in its potential for identifying sites of historical archaeological significance than a resolution of one of history's most enduring questions. While compelling stratigraphic, geochemical and microbiological evidence has been recovered from an alluvial floodplain mire in the upper Guil Valley, located below the Col de la Traversette (about 3000 masl) on the French–Italian border, it potentially identifies the invasion route as the one originally proposed by Sir Gavin de Beer in 1974. The dated layers in several sections, termed the MAD (mass animal deposition) beds based on disrupted/churned bedding and key/specialized biological components strongly supports de Beer's thesis that Hannibal chose the highest transit col into Italia. In addition to other physical evidence, we present here new physical, geomorphological and stratigraphic evidence, all calibrated by radiocarbon dating, that suggests Hannibal's imprint on the landscape exists in coalescing alluvial fans in the upper Po catchment of northern Italy.Makeen, Y.M., Abdullah, W.H., Abdul Ghofur, M.N., Ayinla, H.A., Hakimi, M.H., Shan, X., Mustapha, K.A., Kamal Shuib, M., Liang, Y., Zainal Abidin, N.S., 2019. Hydrocarbon generation potential of Oligocene oil shale deposit at onshore Penyu Basin, Chenor, Pahang, Malaysia. Energy & Fuels 33, 89-105. is the first study that focuses on the evaluation of a newly discovered oil shale deposit in the eastern Chenor area in the state of Pahang, Malaysia. Previously, this deposit was reported as carbonaceous/coaly mudstone. However, in this study, organic-rich immature carbonaceous mudstone containing above 15 wt % total organic carbon (TOC) is evaluated as oil shale, and that below 3.5 wt % TOC is termed mudstone. Oil shale and mudstone, which are significant sedimentary facies for oil and gas exploration, were investigated using organic geochemical and petrological methods, as well as computed tomography (Micro-CT), pyrolysis, and bulk kinetic techniques, to evaluate their hydrocarbon generation potential. The vitrinite reflectance values are less than 0.5% Ro in all of the analyzed samples, indicating low maturity stage. This is corroborated by Tmax values ranging from 383 to 429 °C. However, based on the kinetic simulation model, the average predicted geological temperature for the onset of hydrocarbon generation is 109 °C, while the peak of hydrocarbon generation is 153 °C. The extractable organic matter and hydrocarbon contents results show that the oil shale samples possess excellent petroleum potential compared to very good values for the studied mudstone. This is consistent with the plots of TOC content versus extractable organic matter, and hydrocarbon yields versus TOC content, commonly used in estimating the hydrocarbon generative potential of source rocks. The TOC of these oil shales is consistent with that of the Tertiary oil shale deposits in China. The analyzed oil shale samples are characterized by a high hydrogen index (HI) of up to 700 mg HC/g TOC (average 517.4 mg HC/g TOC), suggesting oil-prone type I and type II kerogens. However, the open pyrolysis-gas chromatography (Py-GC) result of these samples displays a predominance of n-alkene/n-alkane doublets extending to the long-range homologous series (C7–C33) with considerably high aromatic compounds, which indicates type II/III kerogens’ (mixed oil and gas) generative potential. Similarly, bulk kinetic analysis of the analyzed samples suggests typical petroleum source rock facies derived from heterogeneous (type II/III kerogens) organic matter assemblages. Thus, based on the pyrolysis and bulk kinetic result, the studied oil shale can be classified as “‘cannel coal”’ derived from terrestrial plants materials. This is supported by organic petrological and Micro-CT studies which revealed that the samples are composed mainly of liptinite (sporinite, cutinite, amorphous organic matter, and resinite) and vitrinite, with varied trace amounts of inertinite.Mángano, M.G., Hawkes Christopher, D., Caron, J.-B., 2019. Trace fossils associated with Burgess Shale non-biomineralized carapaces: bringing taphonomic and ecological controls into focus. Royal Society Open Science 6, 172074. association of trace fossils and non-biomineralized carapaces has been reported from Cambrian Lagerst?tten worldwide, but the abundance, ichnodiversity, taphonomy and ecological significance of such associations have yet to be fully investigated. Two main end-member hypotheses are explored based on the study of a relatively wide variety of trace fossils preserved associated to Tuzoia carapaces from the middle Cambrian Burgess Shale in British Columbia. In the ecological Tuzoia garden hypothesis, the bacterially enriched surface of carapaces provides opportunities for intricate ecologic interactions among trophic levels. In the taphonomic shielding hypothesis, the trace fossil–carapace association results from preferential preservation of traces as controlled by compaction independent of any association in life. In an attempt to better understand the role of the carapace as a medium for preservation of trace fossils and to evaluate the effects of mechanical stress related to burial, a numerical model was developed. Results indicate that the carapace can shield underlying sediment from mechanical stress for a finite time, differentially protecting trace fossils during the initial phase of burial and compaction. However, this taphonomic model alone fails to fully explain relatively high-density assemblages displaying a diversity of structures spatially confined within the perimeter of carapaces or branching patterns recording re-visitation.Manzano, C.A., Dodder, N.G., Hoh, E., Morales, R., 2018. Patterns of personal exposure to urban pollutants using personal passive samplers and GC × GC/ToF–MS. Environmental Science & Technology 53, 614-624. performance of silicon wristband passive samplers (WB), combined with comprehensive two-dimensional gas-chromatography/time-of-flight mass-spectrometry (GC × GC/ToF–MS), for the analysis of urban derived pollutants in the personal environment was evaluated. Cumulative 5-day exposure samples from 27 individuals in areas with different geographical/socioeconomic characteristics within the Santiago Metropolitan Region (Chile) were collected during winter and summer (2016–2017). Samples were extracted without cleanup/fractionation and analyzed using targeted and nontargeted methods. The quantified semivolatile organic compounds (SVOCs, n = 33) (targeted analysis), and tentatively identified features (n = 595–1011) (nontargeted analysis) were classified according to their use/source. Seasonal differences were observed in the targeted analysis, while seasonal and spatial differences were observed in the nontargeted analysis. Higher concentrations of combustion products were observed in winter, while higher concentrations of consumer products were found in summer. Spatial differences were observed in hierarchical clustering analysis of the nontargeted data, with distinct clusters corresponding to specific subregions of the urban area. Results from this study provide spatial and seasonal distributions of urban pollutants within an urban area and establish the utility of linking WB with nontargeted analysis as a tool to identify and prioritize new exposures to urban contaminants at the local/community level.Markwick, P.J., 2019. Palaeogeography in exploration. Geological Magazine 156, 366-407. is the representation of the past surface of the Earth. It provides the spatial context for investigating how the Earth evolves through time, how complex processes interact and the juxtaposition of spatial information. In hydrocarbon exploration, palaeogeographies have been used to map and investigate the juxtaposition, distribution and quality of play elements (source, reservoir, seal and trap), as boundary conditions for source-to-sink analysis, climate modelling and lithofacies retrodiction, but most commonly as the backdrop for presentations and montages. This paper demonstrates how palaeogeography has been and can be used within an exploration workflow to help mitigate exploration risk. A comprehensive workflow for building palaeogeographies is described which is designed to provide a standard approach that can be applied to a range of tasks in exploration and academia. This is drawn from an analysis of the history of palaeogeography and how it has been applied to exploration in the past and why. Map applications, resolution and content depend on where in the exploration and production (E&P) cycle the map is used. This is illustrated here through three case studies, from the strategic decisions of global new ventures exploration to the more detailed basin and petroleum analyses of regional asset teams evaluating basins and plays. Through this, the paper also addresses three commonly asked questions: (1) How can I use palaeogeography in my workflow? (2) How reliable are the maps? (3) How do I build a palaeogeography?Marques, E.L.S., Dias, J.C.T., Gross, E., e Silva, A.B.d., de Moura, R.S., Rezende, R.P., 2019. Purple sulfur bacteria dominate microbial community in Brazilian limestone cave. Microorganisms 7, Article 29. mineralogical composition of caves makes the environment ideal for inhabitation by microbes. However, the bacterial diversity in the cave ecosystem remains largely unexplored. In this paper, we described the bacterial community in an oxic chamber of the Sopradeira cave, an iron-rich limestone cave, in the semiarid region of Northeast Brazil. The microbial population in the cave samples was studied by 16S rDNA next-generation sequencing. A type of purple sulfur bacteria (PSB), Chromatiales, was found to be the most abundant in the sediment (57%), gravel-like (73%), and rock samples (96%). The predominant PSB detected were Ectothiorhodospiraceae, Chromatiaceae, and Woeseiaceae. We identified the PSB in a permanently aphotic zone, with no sulfur detected by energy-dispersive X-ray (EDX) spectroscopy. The absence of light prompted us to investigate for possible nitrogen fixing (nifH) and ammonia oxidizing (amoA) genes in the microbial samples. The nifH gene was found to be present in higher copy numbers than the bacterial-amoA and archaeal-amoA genes, and archaeal-amoA dominated the ammonia-oxidizing community. Although PSB dominated the bacterial community in the samples and may be related to both nitrogen-fixing and ammonia oxidizing bacteria, nitrogen-fixing associated gene was the most detected in those samples, especially in the rock. The present work demonstrates that this cave is an interesting hotspot for the study of ammonia-oxidizing archaea and aphotic PSB.Marques, E.L.S., Silva, G.S., Dias, J.C.T., Gross, E., Costa, M.S., Rezende, R.P., 2019. Cave drip water-related samples as a natural environment for aromatic hydrocarbon-degrading bacteria. Microorganisms 7, Article 33. contact with the external environment has allowed the development of microbial communities adapted to the oligotrophy of caves. However, nutrients can be transported to caves by drip water and affect the microbial communities inside the cave. To evaluate the influence of aromatic compounds carried by drip water on the microbial community, two limestone caves were selected in Brazil. Drip-water-saturated and unsaturated sediment, and dripping water itself, were collected from each cave and bacterial 16S rDNA amplicon sequencing and denaturing gradient gel electrophoresis (DGGE) of naphthalene dioxygenase (ndo) genes were performed. Energy-dispersive X-ray spectroscopy (EDX) and atomic absorption spectroscopy (AAS) were performed to evaluate inorganic nutrients, and GC was performed to estimate aromatic compounds in the samples. The high frequency of Sphingomonadaceae in drip water samples indicates the presence of aromatic hydrocarbon-degrading bacteria. This finding was consistent with the detection of naphthalene and acenaphthene and the presence of ndo genes in drip-water-related samples. The aromatic compounds, aromatic hydrocarbon-degrading bacteria and 16S rDNA sequencing indicate that aromatic compounds may be one of the sources of energy and carbon to the system and the drip-water-associated bacterial community contains several potentially aromatic hydrocarbon-degrading bacteria. To the best of our knowledge, this is the first work to present compelling evidence for the presence of aromatic hydrocarbon-degrading bacteria in cave drip water.Mazrouei, S., Ghent, R.R., Bottke, W.F., Parker, A.H., Gernon, T.M., 2019. Earth and Moon impact flux increased at the end of the Paleozoic. Science 363, 253-257.: The terrestrial impact crater record is commonly assumed to be biased, with erosion thought to eliminate older craters, even on stable terrains. Given that the same projectile population strikes Earth and the Moon, terrestrial selection effects can be quantified by using a method to date lunar craters with diameters greater than 10 kilometers and younger than 1 billion years. We found that the impact rate increased by a factor of 2.6 about 290 million years ago. The terrestrial crater record shows similar results, suggesting that the deficit of large terrestrial craters between 300 million and 650 million years ago relative to more recent times stems from a lower impact flux, not preservation bias. The almost complete absence of terrestrial craters older than 650 million years may indicate a massive global-scale erosion event near that time.Editor's Summary. Impact rates on Earth and the Moon: The rate at which impacts produce craters on the Moon is used to calibrate ages in planetary science. Earth should also have received similar numbers of impacts, but many craters have been hidden by erosion, ice sheets, and so on. Mazrouei et al. used infrared images of the Moon to estimate the ages of young lunar craters (see the Perspective by Koeberl). They found that the impact rate increased within the past ～500 million years, a conclusion strengthened by an analysis of known impact craters on Earth. Crater size distributions are the same on Earth and the Moon over this period, implying that terrestrial erosion affects all craters equally, regardless of their size.Mazumdar, A., Dewangan, P., Peketi, A., Gullapalli, S., Kalpana, M.S., Naik, G.P., Shetty, D., Pujari, S., Pillutla, S.P.K., Gaikwad, V.V., Nazareth, D., Sangodkar, N.S., Dakara, G., Kumar, A., Mishra, C.K., Singha, P., Reddy, R., 2018. The first record of active methane (cold) seep ecosystem associated with shallow methane hydrate from the Indian EEZ. Journal of Earth System Science 128, 18. we report the discovery of cold-seep ecosystem and shallow methane hydrates (2–3 mbsf) associated with methane gas flares in the water column from the Indian EEZ for the first time. The seep-sites are located in the Krishna–Godavari (K–G) basin at water depths of 900–1800 m and are characterized by gas flares in the water-column images. The occurrence of methane gas hydrates at very shallow depths (2–3 mbsf) at some of the seep-sites is attributed to high methane flux and conducive P–T conditions, necessary for the stability of methane hydrate. Chemosymbiont bearing Bivalves (Vesicomidae, Mytilidae, Thyasiridae and Solemyidae families); Polychaetes (Siboglinidae family) and Gastropods (Provannidae family) are also identified from seep-sites.McCollom, T.M., Donaldson, C., 2019. Experimental constraints on abiotic formation of tubules and other proposed biological structures in subsurface volcanic glass. Astrobiology 19, 53-63. of microtubules in volcanic glass from subsurface environments has been widely attributed to in situ activity of micro-organisms, but evidence directly linking those structures to biological processes remains lacking. Investigations into the alternative possibility of abiotic tubule formation have been limited. A laboratory experiment was conducted to examine whether moderate-temperature hydrothermal alteration of basaltic glass by seawater would produce structures similar to those ascribed to biological processes. Shards of glass were reacted with artificial seawater at 150°C for 48 days. Following reaction, the shards were uniformly covered with a brick-red alteration rind 10–30?μm thick composed primarily of phyllosilicates. Inspection of the margins of reacted shards with light microscopy did not reveal any tubule structures. However, the alteration products did include features containing micron-sized spheroidal structures that resemble granular alteration textures, which some investigators have attributed to biological activity. This result suggests that the granular textures may be at least partially abiotic, and that biological activity may make a smaller contribution to alteration of the oceanic crust than has been previously proposed. Also, while the experimental results do not exclude the possibility that tubules form abiotically, they do place limitations on the conditions under which this may occur.Meinhold, G., 2019. Introduction: Advances in Palaeogeography. Geological Magazine 156, 179-181. special issue of Geological Magazine is dedicated to the memory of Dr Alan Gilbert Smith, Fellow of St John's College and Emeritus Reader in Geology at the University of Cambridge, who passed away on 13 August 2017 at the age of 80. I first met Alan at the 5th International Symposium on Eastern Mediterranean Geology in Thessaloniki, Greece, in spring 2004 and later on several occasions when I was working on the Cambridge Arctic Shelf Programme (CASP) in Cambridge. The palaeotectonic evolution of Greece was one of our common interests. Alan was one of the pathfinders in palaeogeographic research in the 20th century. Together with Sir Edward Bullard (1907–1980) and Jim E. Everett, he published the first computational approach in palaeogeography in their famous paper ‘The fit of the continents around the Atlantic’ (Bullard, Everett &amp; Smith, ), which shows a very accurate geometrical fit of the circum-Atlantic continents using the early Cambridge University EDSAC 2 computer. Later, in a contribution in Nature entitled ‘The fit of the southern continents’, Smith &amp; Hallam () presented the first computer fit of the contour of the southern continents forming Gondwanaland. Worth mentioning also are his detailed palaeogeographical maps of the entire Earth, down to epoch level (e.g. Smith, Briden &amp; Drewry ; Smith, Hurley &amp; Briden ) and his work on the first three editions of A Geologic Time Scale (Harland et al., ; Gradstein, Ogg &amp; Smith ). Alan's great achievements in the Earth sciences have stimulated new ideas and had a huge impact on geological research, including palaeogeography.Meinhold, G., Cel?l ?eng?r, A.M., 2019. A historical account of how continental drift and plate tectonics provided the framework for our current understanding of palaeogeography. Geological Magazine 156, 182-207 is the cartographic representation of the past distribution of geographic features such as deep oceans, shallow seas, lowlands, rivers, lakes and mountain belts on palinspastically restored plate tectonic base maps. It is closely connected with plate tectonics which grew from an earlier theory of continental drift and is largely responsible for creating and structuring the Earth's lithosphere. Today, palaeogeography is an integral part of the Earth sciences curriculum. Commonly, with some exceptions, only the most recent state of research is presented; the historical aspects of how we actually came to the insights which we take for granted are rarely discussed, if at all. It is remarkable how much was already known about the changing face of the Earth more than three centuries before the theory of plate tectonics, despite the fact that most of our present analytical tools or our models were unavailable then. Here, we aim to present a general conspectus from the dawn of ‘palaeogeography’ in the 16th century onwards. Special emphasis is given to innovative ideas and scientific milestones, supplemented by memorable anecdotes, which helped to advance the theories of continental drift and plate tectonics, and finally led to the establishment of palaeogeography as a recognized discipline of the Earth sciences.Miao, Y., Zhao, C., Wu, K., Li, X., 2019. Analysis of production prediction in shale reservoirs: Influence of water film in inorganic matter. Journal of Natural Gas Science and Engineering 63, 1-9. commercially develop shale gas reservoirs, multi-fractured horizontal wells are widely employed in the industry. A number of analytical models have been proposed to evaluate and forecast production from fractured horizontal wells. However, the water film adsorbed in inorganic pores of shale matrix is often neglected and its effect on gas production has never been focused on. Moreover, the effect on gas production caused by the characteristic of a well not located in the center of drainage area has not been drawn much attention. In this work, on a basis of enhanced-fracture-region (EFR) model, a new model is put forward to conduct production prediction of multi-fractured horizontal wells from shale gas reservoirs. This novel approach incorporates critical gas transport mechanisms in shale, and considers the characteristic of a well not located in the center of drainage area. Specifically, this model takes the bulk-gas transport regimes, water film effect, stress dependence and real gas effect into account, which matches well with the real shale reservoirs. The analytical solution of the proposed model is deduced by employing the Laplace transformation approach, and then introducing the numerical algorithm put forward by Stehfest to invert to the real time domain. This presented model is verified by both numerical simulation cases and actual field applications. In addition, a sensitivity study is performed to illustrate various parameters on flow-regime and production curves. Results illustrate that both the size of stimulated zone and distance from the well to the outer boundary contribute to the well performance. A larger size of the stimulated zone increases the duration of the first linear flow period, whereas will shorten the duration of the third boundary dominated flow period. A larger distance from the well to the outer boundary leads to stronger gas production. The real gas has non-obvious effect on gas production. Both the stress dependence and humidity have negative effects on production curves, which are induced by the decrease of the effective pore radius. Specifically, compared with the gas production without considering water film effect, when the humidity value is 0.1, gas production can achieve an average decrease of 18.57%. When the humidity value is 0.3, gas production can reach an average decrease of 26.10%.Michel, A.P.M., Morrison, A.E., Marx, C.T., White, H.K., 2019. Rapid identification of Deepwater Horizon oil residues using X-ray fluorescence. Environmental Science & Technology Letters 6, 34-37. residues are found on Gulf of Mexico beaches due to the Deepwater Horizon (DWH) incident, alongside oil residues from natural seepage and other anthropogenic inputs. To identify the origin of oil residues found on beaches, especially after a spill, it is critical to have techniques that can be used in the field, can provide rapid identification, and can be used easily by response workers. Here we present the utility of a hand-held X-ray fluorescence (XRF) spectrometer to rapidly identify the origin of oil residues. When XRF data were coupled with a machine learning model, DWH samples could be distinguished from not-DWH samples with 95% accuracy. This approach enables the analysis of bulk samples without sample preparation, paving the way for utilizing XRF in the field for immediate oil residue source identification.Michels, J., Stippkugel, A., Lenz, M., Wirtz, K., Engel, A., 2018. Rapid aggregation of biofilm-covered microplastics with marine biogenic particles. Proceedings of the Royal Society B: Biological Sciences 285, 20181203. plastic pollution has resulted in a substantial accumulation of microplastics in the marine environment. Today, this plastic litter is ubiquitous in the oceans, including even remote habitats such as deep-sea sediments and polar sea ice, and it is believed to pose a threat to ecosystem health. However, the concentration of microplastics in the surface layer of the oceans is considerably lower than expected, given the ongoing replenishment of microplastics and the tendency of many plastic types to float. It has been hypothesized that microplastics leave the upper ocean by aggregation and subsequent sedimentation. We tested this hypothesis by investigating the interactions of microplastics with marine biogenic particles collected in the southwestern Baltic Sea. Our laboratory experiments revealed a large potential of microplastics to rapidly coagulate with biogenic particles, which substantiates this hypothesis. Together with the biogenic particles, the microplastics efficiently formed pronounced aggregates within a few days. The aggregation of microplastics and biogenic particles was significantly accelerated by microbial biofilms that had formed on the plastic surfaces. We assume that the demonstrated aggregation behaviour facilitates the export of microplastics from the surface layer of the oceans and plays an important role in the redistribution of microplastics in the oceans.Mills, B.J.W., Krause, A.J., Scotese, C.R., Hill, D.J., Shields, G.A., Lenton, T.M., 2019. Modelling the long-term carbon cycle, atmospheric CO2, and Earth surface temperature from late Neoproterozoic to present day. Gondwana Research 67, 172-186. geological timescales, CO2 levels are determined by the operation of the long term carbon cycle, and it is generally thought that changes in atmospheric CO2 concentration have controlled variations in Earth's surface temperature over the Phanerozoic Eon. Here we compile independent estimates for global average surface temperature and atmospheric CO2 concentration, and compare these to the predictions of box models of the long term carbon cycle COPSE and GEOCARBSULF. We find a strong relationship between CO2 forcing and temperature from the proxy data, for times where data is available, and we find that current published models reproduce many aspects of CO2 change, but compare poorly to temperature estimates. Models are then modified in line with recent advances in understanding the tectonic controls on carbon cycle source and sink processes, with these changes constrained by modelling 87Sr/86Sr ratios. We estimate CO2 degassing rates from the lengths of subduction zones and rifts, add differential effects of erosion rates on the weathering of silicates and carbonates, and revise the relationship between global average temperature changes and the temperature change in key weathering zones. Under these modifications, models produce combined records of CO2 and temperature change that are reasonably in line with geological and geochemical proxies (e.g. central model predictions are within the proxy windows for >~75% of the time covered by data). However, whilst broad long-term changes are reconstructed, the models still do not adequately predict the timing of glacial periods. We show that the 87Sr/86Sr record is largely influenced by the weathering contributions of different lithologies, and is strongly controlled by erosion rates, rather than being a good indicator of overall silicate chemical weathering rates. We also confirm that a combination of increasing erosion rates and decreasing degassing rates over the Neogene can cause the observed cooling and Sr isotope changes without requiring an overall increase in silicate weathering rates. On the question of a source or sink dominated carbon cycle, we find that neither alone can adequately reconstruct the combination of CO2, temperature and strontium isotope dynamics over Phanerozoic time, necessitating a combination of changes to sources and sinks. Further progress in this field relies on >108?year dynamic spatial reconstructions of ancient tectonics, paleogeography and hydrology. Whilst this is a significant challenge, the latest reconstruction techniques, proxy records and modelling advances make this an achievable target.Milman, B.L., Gostev, V.V., Dmitriev, A.V., 2018. A comparison of “low-molecular” and conventional approaches to the species identification of bacteria by MALDI mass spectrometry. Journal of Analytical Chemistry 73, 1217-1222. new approach to bacteria identification that uses the standard software for building mass spectral libraries of low-molecular compounds and for corresponding library searches is compared with the conventional approach based on the commercial Biotyper software and database. The results are obtained for a random sample of 100 mass spectra of 25 strains of S. pyogenes, S. dysgalactiae subsp. equisimilis, and S. anginosus. The spectra were sampled from the database of 728 mass spectra of 182 strains for some Streptococcus species. Both approaches were proved to result in the similar identification as 80–88% of the true outcomes. For similar reference mass spectra and the same identification criteria, the results of identification were very close to each other as 24 agreements for 25 strains. This is because different estimations of mass spectral similarity included in the programs under comparison lead to a correlation of similarity indicators. The difference in usual identification results is mainly due to different reference databases and also different identification criteria.Min, X., Hua, H., Cai, Y., Sun, B., 2019. Asexual reproduction of tubular fossils in the terminal Neoproterozoic Dengying Formation, South China. Precambrian Research 322, 18-23. fossils are an abundant and diverse component of late Ediacaran benthic communities. However, with rare exceptions, their development and modes of asexualreproduction remain poorly resolved. With the deeper research and more specimens recovered, the types of asexual reproduction of tubular fossils are clarified. Three-dimensionally phosphatized tubes from the Ediacaran Dengying Formation in Lijiagou (southern Shaanxi Province, China) provide a window into the reproduction of late Ediacaran tubular fossils. In this paper, we document two different styles of asexual reproduction associated with two morphotypes of the biomineralized tubular fossil and propose upper Ediacaran index fossil Cloudina (type A with bud from the aperture of parent tube and type B with new bud from the lateral of parent tube, type C with two similar diameter individual tubes) and the new genus Multiconotubus (type E and type F with individual tubes but living in the parent tube). What is the most important is that based on the internal structure of dichotomous Multiconotubus, and observing means of x-ray micro-tomography, we can see clearly the internal structure and we propose a new growth strategy for this organism. In this paper, we emphasize the asexual budding reproduction and the multiple common wall reproduction.Mironenko, M.V., Polyakov, V.B., Alenina, M.V., 2018. Simultaneous calculation of chemical and isotope equilibria using the GEOCHEQ_Isotope software: Carbon isotopes. Geochemistry International 56, 1354-1367. program package GEOCHEQ_Isotope was developed for the simultaneous calculation of chemical and isotope equilibria in hydrothermal and hydrochemical systems by the method of Gibbs free energy minimization. It utilizes the formalism of the β-factor and is a modification of the GEOCHEQ software, which was designed to calculate chemical equilibria. An algorithm was proposed for the calculation of the Gibbs free energy of formation of a rare isotopologue, G*(P, T), from the Gibbs free energy of formation of the main isotopologue, the β-factor of this substance, and the mass ratio of the rare and main?isotopes of the element. The ideal mixing of isotopes was assumed. The temperature dependence of the β-factor was unified as a polynomial in reciprocal absolute temperature. The implementation of the software and an appropriate database was illustrated by the example of carbon isotopes. The available information on carbon isotope equilibria involving geochemically important compounds was critically analyzed, and temperature dependences of their β-factors were correspondingly optimized. The thermodynamic database was updated by adding information on the temperature dependence of β-factors specified by eight polynomial coefficients for each substance. The use of the GEOCHEQ_Isotope was exemplified calculating the equilibrium compositions of phases and carbon isotope fractionations in carbonate hydrothermal systems with and without iron at pH ranging from 4 to 11.Miyake, F., Horiuchi, K., Motizuki, Y., Nakai, Y., Takahashi, K., Masuda, K., Motoyama, H., Matsuzaki, H., 2019. 10Be signature of the cosmic ray event in the 10th century CE in both hemispheres, as confirmed by quasi-annual 10Be data from the Antarctic Dome Fuji ice core. Geophysical Research Letters 46, 11-18.: Cosmogenic nuclides are good indicators of past cosmic ray events and variations. To verify such phenomena, it is important to evaluate them using multiple nuclides from different archives. The cosmic ray event in 993–994 Common Era (CE) has already been confirmed with 14C and 10Be data, which show rapid increases in the concentrations. However, the 10Be data were obtained from the Greenland ice cores in the Northern Hemisphere. To investigate the extent of the 10Be increase in the Southern Hemisphere, we measured quasi‐annual 10Be concentrations between 980 and 1,011 CE in the Antarctic Dome Fuji ice core. We observed a ~50% increase in 10Be concentration around 994 CE, consistent with the Greenland data. Increases in 10Be concentrations in both hemispheres support a solar origin of the 994‐CE event. In addition, we propose a method of evaluating the so‐called “system effect” for 10Be deposition by extracting common components from 10Be and Na+ data.Plain Language Summary: New quasi‐annual beryllium‐10 measurements were made with the Dome Fuji ice core from Antarctica over the period in which the 994 cosmic ray event would be expected. We observed an approximately 50% increase in beryllium‐10 concentrations, which is consistent with the beryllium‐10 increases observed in the Greenland ice cores. This lends support to a solar origin of the 994 event. We propose a phenomenological method for evaluating a common deposition component between quasi‐annual beryllium‐10 and sodium ion data.Moir, M.E., 2018. Asphaltenes, What art thou?, in: Ovalles, C., Moir, M.E. (Eds.), The Boduszynski Continuum: Contributions to the Understanding of the Molecular Composition of Petroleum. American Chemical Society, pp. 3-24. his career Mietek Boduszynski challenged the prevailing ideas about the nature of asphaltenes, a solubility fraction obtained from petroleum by the addition of alkane solvents. He demonstrated that the long-held notion of asphaltenes as molecules of high molecular weight was incorrect. In addition, he reasoned that the molecules contained in this fraction were simply part of the continuum of molecules in petroleum. In this chapter, the origin of the term asphaltene, the history of the science of asphaltenes, and how the current state of knowledge aligns with the model of petroleum proposed by Boduszynski will be examined.Moncada, J., Schartung, D., Stephens, N., Oh, T.-S., Carrero, C.A., 2019. Determining the flocculation point of asphaltenes combining ultrasound and electrochemical impedance spectroscopy. Fuel 241, 870-875. characterization of asphaltenes in heavy crude oil remains relevant as continuous extraction of conventional oil pushes industries to seek oil from new, unconventional sources. Unconventional crude oil contains a high concentration of asphaltenes, resulting in a very dense (22.3-10?°API) and viscous substance, which makes the handling and processing of this type of petroleum more challenging. The flocculation of asphaltenes is still a challenge to address during crude oil production, transportation, blending, and processing. Therefore, understanding the phase behavior of asphaltenes as well as their stability and physicochemical properties demands new and more practical characterization techniques capable of providing new insights into the asphaltene flocculation process. Current characterization techniques used to determine the flocculation point of asphaltenes in crude oil are primarily based on optical techniques and ex-situ methodologies. In this work, we propose, investigate, and provide preliminary results on a new approach aimed to determine the flocculation point of asphaltenes using electrochemical impedance spectroscopy (EIS) assisted by ultrasound (US). Our results show that the asphaltene flocculation process is significantly influenced by using US pulses, which promote the disaggregation of asphaltenes, thus allowing the determination of the flocculation point of asphaltenes via EIS.Moodie, N., Ampomah, W., Jia, W., Heath, J., McPherson, B., 2019. Assignment and calibration of relative permeability by hydrostratigraphic units for multiphase flow analysis, case study: CO2-EOR operations at the Farnsworth Unit, Texas. International Journal of Greenhouse Gas Control 81, 103-114. the most critical factors for geological CO2 storage site screening, selection, and operation is effective simulations of multiphase flow and transport. Relative permeability is probably the greatest source of potential uncertainty in multiphase flow simulation, second only to intrinsic permeability heterogeneity. The specific relative permeability relationship assigned greatly impacts forecasts of CO2 trapping mechanisms, phase behavior, and long-term plume movement. A primary goal of this study is to evaluate the impacts and implications of different methods of assigning relative permeability relationships for CO2-EOR model forecasts. Most simulation studies published in the literature base selection of relative permeability functions on the geologic formation or rock type alone. In this study, we initially implemented reservoir model grids with previously-identified hydrostratigraphic units based on porosity and permeability relationship of the Morrow ‘B’ Sandstone, then assigned relative permeability functions for those hydrostratigraphic units. Specific, constrained relative permeability relationships were created and assigned to each hydrostratigraphic unit using petrophysical data and Mercury Intrusion Capillary Pressure (MICP) measurements, from core samples of each hydrostratigraphic unit. Results of forward simulations with the newly-calibrated models will be compared to those of previous models as well as to simulation results for a range of different relative permeability relationships. The study site is the Farnsworth Unit (FWU) in the northeast Texas Panhandle, an active CO2-EOR operation. The target formation is the Morrow ‘B’ Sandstone, a clastic formation composed of medium to course sands.Moon, J., Xia, K., Williams, M.A., 2019. Consistent proteinaceous organic matter partitioning into mineral and organic soil fractions during pedogenesis in diverse ecosystems. Biogeochemistry 142, 117-135. compounds are critical in soil organic matter (SOM) formation and persistence, but the partitioning into mineral-associated and organic forms during hundreds and thousands of years of pedogenesis are poorly understood across multiple climates and vegetation types. We investigated the partitioning of amino acids (AA) into mineral-bound (MB) and non-mineral associated organic (NMO) soil fractions to discern whether consistent patterns during ecosystem development were observed across two different climates (cool temperate continental, USA; and moist oceanic forests, New Zealand). Although each ecosystem retained unique soil AA signatures, consistent patterns in both systems were observed with three main findings. (1) Regardless of differences in climate and vegetation between the two ecosystems, AA consistently partitioned in similar ways into MB and NMO soil fractions. For example, Thr, Ser, and Asx were relatively more dominant in the NMO fraction while Arg, Lys, Cys, and Met were relatively more dominant in the MB soil fraction. (2) AA change, showed similar trends related to chemical groupings of positively-charged, polar aromatic, sulfur containing, and non-polar AAs across both ecosystems consistent with changing patterns of soil Fe and Al bearing minerals, such as an increasing weathering index (WI; Fe dithionite/total Fe)?and losses of Fe and Al from surface soils during ecosystem development. (3) The pedogenic patterns of AA change, in each system paralleled biological transitions in bacterial communities, suggesting a linkage between the AA sources and the soil sink that contributes to soil organic N. This latter point contrasts with the potential for complete change in soil AA composition that could occur upon processing and binding in soil. Overall, the consistency in the types of AAs that partition into either MB or NMO soil fractions across locations provide evidence of similar processes that contribute to soil organic N accrual across soils. Some AA also appeared to be retained in soil by electrostatic forces, and AA–organic matter interactions, that need further study. Mineral–metal complexation of AAs with sulfur side chain groups, and non-polar interactions, respectively, provide examples of these potential mechanisms for study. The results not only support mechanisms of soil proteinacous organic matter chemistry being driven by the interactions with the soil matrix, acting as a “sink”, but also draw attention to the sources of organic matter (microbes, plants) in determining the composition of organic N in soil during pedogenesis.Moradi, S., Isari, A.A., Bachari, Z., Mahmoodi, H., 2019. Combination of a new natural surfactant and smart water injection for enhanced oil recovery in carbonate rock: Synergic impacts of active ions and natural surfactant concentration. Journal of Petroleum Science and Engineering 176, 1-10. increasing oil demand in carbonate reservoirs, enhanced oil recovery techniques play key role in improving oil production. Surfactant flooding and smart water injection are already well known as effective enhanced oil recovery techniques that increase oil recovery by reduction of oil-water interfacial tension and the alteration of rock wettability. In this work, a new plant-base natural surfactant, named Tribulus Terrestris is introduced and combined with smart water samples (i.e. synthetic seawater with different concentrations of active Ca2+, Mg2+ and SO42? ions) to determine their individual and integrated effects on reduction in interfacial tension, wettability alteration and oil recovery in carbonate rock samples. It was observed that increasing concentrations of SO42? up to 2.5 times resulted in maximum wettability restoration among active ions (by changing contact angle from 145.9° to 54.4°). Experimental results also showed that the effect of the concentration of active ions on wettability alteration was more significant compared to their effect on decreasing oil-water interfacial tension. In addition, the Tribulus Terrestris surfactant reduced oil-water interfacial tension considerably (from 45.3?mN/m to 13.5?mN/m at Critical Micelle Concentration of 0.3?wt %); hence, it was used as smart water modifier to integrate effects of wettability alteration (by smart water) and reduction in interfacial tension (by new natural surfactant). Core flooding experiments demonstrated increased oil recovery from 45.2% for distilled water injection up to 64% and 72% for smart water and combined smart water-surfactant respectively.Murgia, M., Fiamma, M., Barac, A., Deligios, M., Mazzarello, V., Paglietti, B., Cappuccinelli, P., Al-Qahtani, A., Squartini, A., Rubino, S., Al-Ahdal, M.N., 2019. Biodiversity of fungi in hot desert sands. MicrobiologyOpen 8, e00595. fungal community of six sand samples from Saudi Arabia and Jordan deserts was characterized by culture‐independent analysis via next generation sequencing of the 18S rRNA genes and by culture‐dependent methods followed by sequencing of internal transcribed spacer (ITS) region. By 18S sequencing were identified from 163 to 507 OTUs per sample, with a percentage of fungi ranging from 3.5% to 82.7%. The identified fungal Phyla were Ascomycota, Basal fungi, and Basidiomycota and the most abundant detected classes were Dothideomycetes, Pezizomycetes, and Sordariomycetes. A total of 11 colonies of filamentous fungi were isolated and cultured from six samples, and the ITS sequencing pointed toward five different species of the class Sordariomycetes, belonging to genera Fusarium (F. redolens, F. solani, F. equiseti), Chaetomium (C. madrasense), and Albifimbria (A. terrestris). The results of this study show an unexpectedly large fungal biodiversity in the Middle East desert sand and their possible role and implications on human health.Musumeci, M.A., Loviso, C.L., Lozada, M., Ferreira, F.V., Dionisi, H.M., 2019. Substrate specificities of aromatic ring-hydroxylating oxygenases of an uncultured gammaproteobacterium from chronically-polluted subantarctic sediments. International Biodeterioration & Biodegradation 137, 127-136. ring-hydroxylating oxygenases (RHOs) are multicomponent enzymes that catalyze the vicinal hydroxylation of aromatic rings to produce cis-dihydrodiols, a key step in the aerobic biodegradation of aromatic compounds. In this work, we describe the characterization of three RHOs of an uncultured gammaproteobacterium from chronically polluted Subantarctic intertidal sediments. Sequences encoding the α and β subunits of these RHOs, classified as class A type III, and one set of the corresponding electron transfer partners, were identified in a 34?Kb fragment from a metagenomic fosmid library. Structural modeling and docking analyses suggested that the active sites of these enzymes accommodated different set of substrates. The three enzymes, including the electron transfer components, were expressed in Escherichia coli and purified. The enzyme with the largest predicted catalytic pocket and wider diameter channels presented remarkably relaxed substrate specificity, including 2–4 ring PAHs (phenanthrene, pyrene, fluoranthene and naphthalene). The other two RHOs were stricter in their substrate specificity, and hydroxylated biphenyl and naphthalene more efficiently. These results suggest the evolution of compatible RHO enzymes within a single catabolic gene cluster in this microorganism. This work increases our understanding of the PAH-degrading capabilities of uncultured bacteria from cold coastal environments.Nandwani, S.K., Malek, N.I., Chakraborty, M., Gupta, S., 2018. Potential of a novel surfactant slug in recovering additional oil from highly saline calcite cores during the EOR process: Synergistic blend of surface active ionic liquid and nonionic surfactant. Energy & Fuels 33, 541-550. the present study, a chemical formulation containing a surface-active ionic liquid (SAIL; tributylhexadecylphosphonium bromide) and a nonionic surfactant (TERGITOL 15-S-9) has been prepared. The composition of the mixed micelle and the interaction parameter between the SAIL and nonionic surfactant at varying concentrations were evaluated by Rubingh theory. The most optimal formulation was then screened through phase behavior tests to determine optimal salinity for the crude/brine/chemical formulation system. The optimal salinity for the oil/water/surfactant system was found to be as high as 9.28 wt %. Dynamic light scattering (DLS) studies and small-angle neutron scattering (SANS) experiments have been performed to provide further insight into the size and structure of the micelles formed by the SAIL and nonionic surfactant, respectively. Traditional laboratory-scale oil displacement experiments were performed to study the effectiveness of the optimized chemical formulation in recovering oil during the surfactant-assisted EOR process. Prolate ellipsoidal-shaped mixed micelles, formation of a WINSOR III phase at high salinities, low equilibration time, and prolonged stability of the ternary phase system facilitate high oil solubilization. It was observed that, after the secondary waterflooding process, during the tertiary oil recovery process, individual nonionic surfactant at the same salinity recovered only 7.28% additional oil, whereas the optimized chemical formulation containing both SAIL and nonionic surfactant in an equimolar ratio recovered 16.68% additional oil.Nauer, P.A., Hutley, L.B., Arndt, S.K., 2018. Termite mounds mitigate half of termite methane emissions. Proceedings of the National Academy of Sciences 115, 13306-13311.: Termites are important decomposers of plant material in tropical ecosystems, and thereby produce globally significant amounts of the greenhouse gas CH4. Here, we provide a mechanistic understanding of CH4 turnover in termite mounds to fill a long-standing knowledge gap. Using field measurements, we show that termite mounds oxidize, on average, half of the CH4 produced by termites before emission. This “hidden” biofilter mechanism is mediated by methanotrophic bacteria living in the mound walls or the soil beneath, for which internal termite-mound structures can facilitate CH4 transport. Process links within the mound stabilize the filter efficiency. Moreover, we estimate undisturbed termite biomass via CH4 emissions. This knowledge is crucial to reduce uncertainty in global termite-derived CH4 emissions.Abstract: Termites are responsible for ～1 to 3% of global methane (CH4) emissions. However, estimates of global termite CH4 emissions span two orders of magnitude, suggesting that fundamental knowledge of CH4 turnover processes in termite colonies is missing. In particular, there is little reliable information on the extent and location of microbial CH4 oxidation in termite mounds. Here, we use a one-box model to unify three independent field methods—a gas-tracer test, an inhibitor approach, and a stable-isotope technique—and quantify CH4 production, oxidation, and transport in three North Australian termite species with different feeding habits and mound architectures. We present systematic in situ evidence of widespread CH4 oxidation in termite mounds, with 20 to 80% of termite-produced CH4 being mitigated before emission to the atmosphere. Furthermore, closing the CH4 mass balance in mounds allows us to estimate in situ termite biomass from CH4 turnover, with mean biomass ranging between 22 and 86 g of termites per kilogram of mound for the three species. Field tests with excavated mounds show that the predominant location of CH4 oxidation is either in the mound material or the soil beneath and is related to species-specific mound porosities. Regardless of termite species, however, our data and model suggest that the fraction of oxidized CH4 (fox) remains well buffered due to links among consumption, oxidation, and transport processes via mound CH4 concentration. The mean fox of 0.50 ± 0.11 (95% CI) from in situ measurements therefore presents a valid oxidation factor for future global estimates of termite CH4 emissions.Nesb?, C.L., Charchuk, R., Pollo, S.M.J., Budwill, K., Kublanov, I.V., Haverkamp, T.H.A., Foght, J., 2019. Genomic analysis of the mesophilic Thermotogae genus Mesotoga reveals phylogeographic structure and genomic determinants of its distinct metabolism. Environmental Microbiology 21, 456-470. genus Mesotoga, the only described mesophilic Thermotogae lineage, is common in mesothermic anaerobic hydrocarbon‐rich environments. Besides mesophily, Mesotoga displays lineage‐specific phenotypes, such as no or little H2 production and dependence on sulfur‐compound reduction, which may influence its ecological role. We used comparative genomics of 18 Mesotoga strains (pairwise 16S rRNA identity >99%) and a transcriptome of M. prima to investigate how life at moderate temperatures affects phylogeography and to interrogate the genomic features of its lineage‐specific metabolism. We propose that Mesotoga accomplish H2 oxidation and thiosulfate reduction using a sulfide dehydrogenase and a hydrogenase‐complex and that a pyruvate:ferredoxin oxidoreductase acquired from Clostridia is responsible for oxidizing acetate. Phylogenetic analysis revealed three distinct Mesotoga lineages (89.6%–99.9% average nucleotide identity [ANI] within lineages, 79.3%–87.6% ANI between lineages) having different geographic distribution patterns and high levels of intra‐lineage recombination but little geneflow between lineages. Including data from metagenomes, phylogeographic patterns suggest that geographical separation historically has been more important for Mesotoga than hyperthermophilic Thermotoga and we hypothesize that distribution of Mesotoga is constrained by their anaerobic lifestyle. Our data also suggest that recent anthropogenic activities and environments (e.g., wastewater treatment, oil exploration) have expanded Mesotoga habitats and dispersal capabilities.Nguyen, T.-B., Vesovic, V., 2019. Predicting the viscosity of liquid mixtures consisting of n-alkane, alkylbenzene and cycloalkane species based on molecular description. Fluid Phase Equilibria 487, 58-70. Extended Hard-Sphere (1-cEHS) model has been developed recently to predict the viscosity of liquid, n-alkane mixtures. It represents a mixture by a single pseudo-component characterized by an appropriate molecular weight and calculates the viscosity by means of the modified, extended hard-sphere model (EHS) that makes use of a universal function relating reduced viscosity to reduced volume. In this work we have extended the model to also predict the viscosity of mixtures containing alkylbenzene and cycloalkane species. Furthermore, we have developed a new 3-component Extended Hard-Sphere (3-cEHS) model which requires only a knowledge of the overall composition of n-alkane, alkylbenzene and cycloalkane species. Extensive comparison with the available experimental data indicates that both models (1-cEHS and 3-cEHS) predict the viscosity of binary and multicomponent mixtures containing n-alkane, alkylbenzene and cycloalkane species with uncertainty of 5–10%. The proposed models are a precursor of a new family of models that do not require a knowledge of the detailed composition of the mixture, but still take advantage of the underlying molecular description.Nitsch, E.K., Lamb, A.L., Heaton, T.H.E., Vaiglova, P., Fraser, R., Hartman, G., Moreno-Jiménez, E., López-Pi?eiro, A., Pe?a-Abades, D., Fairbairn, A., Eriksen, J., Bogaard, A., 2019. The preservation and interpretation of δ34S values in charred archaeobotanical remains. Archaeometry 61, 161-178. measurement of sulphur isotope (δ34S) values in charred plant remains has the potential to inform understanding of the spatial configuration and ecology of crop production. We investigated the effects of charring, manuring, oxidation and anaerobic soil conditions on modern cereal grain/pulse seed δ34S values, and assessed the effect of chemical pre‐treatment on charred modern and archaeobotanical grain/seed δ34S values. We used these results to interpret δ34S values in archaeobotanical material from Neolithic ?atalh?yük. Our results suggest that δ34S values can be reliably preserved in charred grain/seeds but are subject to influence by anaerobic soil conditions, the effect depending on the timing of flooding in relation to S assimilation.Niu, M., Liang, W., Wang, F., 2018. Methane biotransformation in the ocean and its effects on climate change: A review. Science China Earth Sciences 61, 1697-1713. is a potent greenhouse gas. Continental margins contain large reservoirs of methane as solid gas hydrate and the dissolved and gaseous forms of methane. Submarine methane seeps along the global continental margins, including the coastal seas, have been estimated to contribute 0.01 to 0.05 Gt of carbon to the atmosphere annually, accounting for between 1% and 5% of the global methane emissions to the atmosphere. Much of this methane is exhausted via microbial anaerobic methane oxidation. Methane biotransformation in the ocean has effects on global climate change. This review mainly introduces the mechanisms of methanogenesis and methane oxidation and describes new findings that will provide information that will improve the understanding of the balance in terms of the generation, migration and consumption of methane in marine environments. Moreover, this review provides new insights into methane biogeochemical cycles and the effects of marine methane budgets on global climate.Niyonsaba, E., Manheim, J.M., Yerabolu, R., Kentt?maa, H.I., 2019. Recent advances in petroleum analysis by mass spectrometry. Analytical Chemistry 90, 156-177. characterization of petroleum is a challenging task due to its inherently complex nature. For example, crude oil is believed to have as many or more compounds than the number of genes in the human genome.(1) As the depletion of light crude oil has increased the reliance by petroleum industry on heavier crude oils, the ability to carry out detailed chemical analysis of petroleum is essential to improve the efficiency of crude oil recovery from oil wells and its processing.(2) Of the diverse classes of compounds found in petroleum, including saturated hydrocarbons, aromatic hydrocarbons, polar compounds, and asphaltenes, the saturated and aromatic hydrocarbons are the most useful for generation of fuels and other valuable products.(3) Compounds containing heteroatoms, such as nitrogen, oxygen, or sulfur, and metals, including vanadium and nickel, are notorious for their toxicity to the environment and for destroying processing catalysts and decreasing the stability of petroleum products.(4) The asphaltene fraction presents its own unique problems as these compounds tend to poison catalysts and precipitate out in pipelines, which leads to increased maintenance costs.(5) For more effective recovery and refining of crude oil, more accurate knowledge of the average molecular weight of compounds in petroleum, their molecular structures, and their abundances is crucial.Mass spectrometry has played a critical role in the characterization of petroleum. The development of very high-resolution instruments has led to a tremendous amount of information on the elemental compositions of the compounds in petroleum samples. Especially, the utilization of a 21 T Fourier-transform ion cyclotron resonance mass spectrometer (21 T FTICR MS) has produced unmatched breadth and depth of compositional information.(6,7) Further, the combination of mass spectrometry and chromatography, including gas chromatography (GC), 2D GC (GC × GC), high-performance liquid chromatography (HPLC), and gel permeation chromatography (GPC), has provided a greater understanding on the types and amounts of certain chemical classes in petroleum. Also, chemometrics is becoming an important analytical tool for determining the origins of unknown petroleum samples as well as differentiating petroleum samples based on mass spectral data. The growing field of petroleomics, defined by Marshall and Rodgers as the characterization of petroleum at the molecular level, has seen many advances in recent years.(8) This review is a continuation to a previous review published by Ryan Rodgers and Amy McKenna,(9) Petroleum Analysis, that covers the developments in mass spectrometric characterization of petroleum samples from 2015 until 2018. The most recent advances in mass spectrometry instrumentation, ionization methods, and fractionation methods for petroleum analysis will be first described, followed by discussion on applications of mass spectrometry in the analysis of common petroleum classes, such as asphaltenes, saturated hydrocarbons, naphthenic acids, and metals, and ending with a perspective on future directions for petroleum analysis.Noiriel, C., Oursin, M., Saldi, G., Haberthür, D., 2019. Direct determination of dissolution rates at crystal surface using 3D X-ray micro-tomography. ACS Earth and Space Chemistry 3, 100-108. of mineral surface reactivity have recently challenged the classical approach of determining dissolution rates from mineral powders as crystals often exhibit heterogeneous and/or anisotropic reactivity. However, face-specific measurements are restricted to small areas at the surface, limited depth, and ignore the contribution of the crystal edges to the whole process. Here, we provide a detailed characterization of the dissolution kinetics at pH 4.0 of a single calcite crystal in 3D using X-ray micro-tomography with a resolution below 1 ?m. The imaging method allows 3D mapping of the crystal surface topography, providing a description of the time-dependent local dissolution fluxes all over the crystal surface, and the calculation of the crystal dissolution rates. The global rate determined at the crystal scale integrates the contribution of all the crystal features, including the faces, edges and corners, which can be detailed in the local rate distributions. Under acidic conditions, pits develop at the surface, before dissolution tends to smooth out both the crystal surface asperities and the edges and corners. In addition, a high rate variability is noticed over the crystal surface. The heterogeneous dissolution rates at the crystal surface first led to a local increase of the surface roughness due to pit formation and coalescence, followed by a decrease of the global crystal roughness due to smoothing of the large-scale surface asperities, crystal edges and corners. Etch pits dominate initially the surface topography, whereas the evolution of the crystal morphology is dominated by the reactivity of edges and corners, whose contribution to dissolution is on average 1.7 to 3.6 times higher than the crystal faces. These results suggest that dissolution reaction preferentially occurs at the crystal edges and corners, something not considered in most studies of mineral dissolution.Novaki, L.P., Keppeler, N., Kwon, M.M.N., Paulucci, L.T., de Oliveira, M.C.K., Meireles, F.A., Baader, W.J., El Seoud, O.A., 2019. Dissolution of asphaltene in binary mixtures of organic solvents and model maltenes: Unambiguous evidence for asphaltene preferential solvation and relevance to assessing the efficiency of additives for asphaltene stabilization. Energy & Fuels 33, 58-67. (Asps) are operationally defined as the toluene-soluble but n-pentane- or n-heptane-insoluble fractions, e.g., of crude oils. Therefore, there is intense interest in determining the concentration of n-heptane required to precipitate Asps from their solutions in particular media (solvents, solvent mixtures, and maltenes). Here, we report on the dependence of Asp dissolution in binary mixtures of n-heptane (solvent 1, S1)/organic solvent (solvent 2, S2) over the entire mole fraction range of S2, χS2, and in few selected maltene models (n-heptane + S2 + benzothiazole + n-octyl-1-napthoate). The S2 employed were benzonitrile, cyclohexanone, ethyl benzoate, 1-methylnaphthalene, tetrahydropyran, and toluene. For all S2 and model maltenes, the dependence of wt % dissolved Asp (determined by mass and UV/vis absorbance) on χS2 was nonlinear. We attribute this nonlinear, i.e., nonideal dissolution behavior to “preferential solvation” of the Asp by a component(s) of the medium (binary solvent mixtures and maltenes). Although the occurrence of “solvent sorting” during Asp dissolution was alluded to, this is the first direct and unambiguous evidence for its occurrence. We used solvatochromism to corroborate our rationale about the origin of the Asp nonideal dissolution behavior. The term solvatochromism refers to the effect of the solvent on the color of solvatochromic probes, substances whose spectra are sensitive to the properties of the liquid medium, e.g., its empirical polarity, ET(probe). Recently, we used (E)-2,6-di-tert-butyl-4-[2-(1-hexylquinolin-1-ium-4-yl)vinyl]phenolate, HxQMBu2) to study Asp dissolution in pure solvents and model maltenes. We showed that ET(HxQMBu2) correlates linearly with Hildebrand solubility parameters of pure solvents as well as with lg (wt % dissolved Asps). In the present work, we studied the solvatochromic response of HxQMBu2 in the above-mentioned n-heptane/S2 binary mixtures. Except for toluene/n-heptane mixtures, plots of ET(HxQMBu2) versus χS2 were nonlinear due to probe preferential solvation. We successfully fitted a solvation model to the solvatochromic and Asp dissolution data and extracted the enrichment of the solvation layers in the more polar component(s) of the binary mixture and model maltenes. Our results bear on the assessment of additives employed to stabilize Asps: in the absence of adverse effects of the additive on other properties (e.g., viscosity and water/oil emulsion stability), efficient additives should accumulate in the solvation layer of Asp particles where they displace the nonsolvents, e.g., the saturates.Nowak, H., Schneebeli-Hermann, E., Kustatscher, E., 2019. No mass extinction for land plants at the Permian–Triassic transition. Nature Communications 10, Article 384. most severe mass extinction among animals took place in the latest Permian (ca. 252 million years ago). Due to scarce and impoverished fossil floras from the earliest Triassic, the common perception has been that land plants likewise suffered a mass extinction, but doubts remained. Here we use global occurrence data of both plant macro- and microfossils to analyse plant biodiversity development across the Permian–Triassic boundary. We show that the plant fossil record is strongly biased and that evidence for a mass extinction among plants in the latest Permian is not robust. The taxonomic diversities of gymnosperm macrofossils and of the pollen produced by this group are particularly incongruent. Our results indicate that gymnosperm macrofossils are considerably undersampled for the Early Triassic, which creates the impression of increased gymnosperm extinction in the latest Permian.Nuzzo, M., Tomonaga, Y., Schmidt, M., Valadares, V., Faber, E., Pi?ero, E., Reitz, A., Haeckel, M., Tyroller, L., Godinho, E., Kipfer, R., Terrinha, P.G., Hensen, C., 2019. Formation and migration of hydrocarbons in deeply buried sediments of the Gulf of Cadiz convergent plate boundary - Insights from the hydrocarbon and helium isotope geochemistry of mud volcano fluids. Marine Geology 410, 56-69. geochemical study of the composition of hydrocarbon gases and helium isotopes (3He/4He) in fluids from Mud Volcanoes (MVs) located on and out of the active accretionary wedge of the Gulf of Cadiz (GoC) provides information on fluid sources and migrations in deeply buried sediments. The GoC is a tectonically active segment of the Africa-Iberia plate boundary occluded beneath the thick sediments of an accretionary wedge dissected by crustal-scale strike-slip faults. Initially built during the Miocene Gibraltar Arc subduction, the wedge has since developed toward the W-NW in an oblique convergent setting. Interstitial water expelled from clays undergoing diagenesis in buried sediments drives mud volcanism on the wedge, with MVs located along strike-slip faults mediating fluid ascent. The large excess of radiogenic helium (4He) in all GoC fluids agrees with a clay mineral dehydration source of water. Hydrocarbon gases from all deepwater MVs bear methane having similar stable carbon isotope compositions of ~?50‰VPDB whether fluids are highly enriched in methane relative to heavier homologues (C2+) or not (Methane?/?(Ethane?+?Propane) ~10 to 10,000). We suggest that methane with ?50‰VPDB was largely diffused out of early generating source rocks, and became dissolved in the water expelled by the buried sediments. Consistently, low 3He/4He ratios suggest an open hydrocarbon system: Petroleum accumulations and 3He dissolved in the original sedimentary pore water have mostly escaped into the water column during the major Late Neogene compressional events.At present, some MVs vent CH4-rich fluids from dewatering sediments, while other structures located on active thrusts additionally vent C2+-rich gases generated by active Cretaceous source intervals. By contrast, evaporitic seals preserved petroleum accumulations on the shallow Moroccan Margin, while the westernmost MVs located out of the accretionary wedge vent microbial gas. Olivatto, G.P., Martins, M.C.T., Montagner, C.C., Henry, T.B., Carreira, R.S., 2019. Microplastic contamination in surface waters in Guanabara Bay, Rio de Janeiro, Brazil. Marine Pollution Bulletin 139, 157-162. (MPs) are contaminants of environmental concern that represent a threat to marine systems. Here we report data on the abundance and characteristics of MPs collected from surface waters of the urban Guanabara Bay. Samples were collected, by horizontal trawling of a plankton net on two occasions (summer of 2016). The MPs were obtained from samples by sieving and particles were manually sorted with microscope. Characterization of MPs was accomplished by gravimetry and digital image processing (for quantification and morphology categorization), and chemical composition identified by infrared spectroscopy and elemental analyses. Total MPs ranged from 1.40 to 21.3?particles/m3, which places Guanabara Bay amongst the most contaminated coastal systems worldwide by microplastics. Polyethylene and polypropylene polymers ≤1?mm were the most abundant particles. Therefore, the occurrence of MPs in Guanabara Bay is relevant to understand ecological hazards of exposition to marine biota and merits further investigation.Ondrasek, G., Baki? Begi?, H., Zovko, M., Filipovi?, L., Meri?o-Gergichevich, C., Savi?, R., Rengel, Z., 2019. Biogeochemistry of soil organic matter in agroecosystems & environmental implications. Science of The Total Environment 658, 1559-1573. biogeochemistry of soil organic matter (SOM), as a highly complex and dynamic soil property, is of vital importance for the health and ecological functioning of ecosystems, including managed and natural ones. Dominantly composed of carbon (C), SOM functions in global C cycling, including C sequestration and emission (e.g. soil respiration). Mediterranean agroecosystems especially, due to favourable climate conditions for mineralisation of SOM, are expected to go through enhanced SOM decomposition (i.e. C emission) under the ongoing global warming and related climatic change and variability (frequent heat waves, fires and extreme water disturbances). The relatively stable (humified) SOM components, especially in the organically-enriched topsoil layers, due to their specific physical chemistry (strongly charged interface) may have a significant role in biogeochemistry of charged (in)organic nutrients and/or contaminants such as toxic metal ions and persistent organic pollutants. The recent studies show that some natural vulnerabilities of Mediterranean regions (such as high risk of the erosion-driven processes) can increase movement of some hazardous pedospheric constituents (e.g. pesticides) to water bodies and/or into the air, thus influencing the whole ecosystem health. A majority of recent surveys confirm depletion of SOM and spatially variable distribution of metal contamination in the Mediterranean topsoils. Using the advanced geochemical prediction approaches in combination with the relevant soil databases, we characterised organo-mineral and organo-metal complexation and its effect on speciation and sorption of trace metals in karstified Mediterranean agroecosystems. Metal biogeochemistry was found to vary markedly under relatively constant pedosphere conditions, depending on organo-mineral soil components and pH, which may significantly impact metal mobility/availability in the soil-plant continuum. The knowledge of the SOM spatial distribution and dynamics and its interactions with other pedovariables is essential for sustainable management of SOM and control of contaminant mobility to avoid degradation processes in (agro)ecosystems.Onwe-Moses, F.D., Eze, S.O., Okoro, A.U., Aghamelu, O.P., 2019. Organic geochemical evaluation and hydrocarbon prospects of the Coniacian Awgu Formation, southern Benue Trough, Nigeria. Arabian Journal of Geosciences 12, 77. of shale from the Coniacian Awgu Formation (southern Benue Trough, Nigeria) were subjected to petro-geochemical analyses in order to determine the hydrocarbon potentials of the formation. The results of the analyses, which included total organic carbon (TOC) content determination and Rock-Eval pyrolysis, show that TOC ranges from 0.53 to 2.91?wt% (with average value of 1.76?wt%), while the generative potential and the hydrogen index range from 0.56 to 3.42?mg HC/g (av. 1.93?mg HC/g) and 67 to 109?mg HC/g TOC (av. 94?mg HC/g TOC), respectively. The results also show vitrinite reflectance value that vary between 0.52 and 0.63% Ro (av. 0.60% Ro) and pyrolysis temperature 428 to 433?°C (av. 431?°C), and organic matter predominantly the type III. On the basis of the TOC, the average TOC (1.76?wt%) exceeds the minimum value of 0.50?wt% required for good hydrocarbon source rocks, and the other assessed parameters which indicate terrestrial-sourced organic matter, this study reveals that the Awgu Formation is a potential source rock, but with more capabilities to generate gas than oil. The overall thermal maturity stage of the kerogens in the formation is within the immature to early (threshold) mature.Ortmann, A.C., Cobanli, S.E., Wohlgeschaffen, G., Thamer, P., McIntyre, C., Mason, J., King, T.L., 2019. Inorganic nutrients have a significant, but minimal, impact on a coastal microbial community's response to fresh diluted bitumen. Marine Pollution Bulletin 139, 381-389. capable of degrading hydrocarbons in oil are present in low abundances in coastal waters, but quickly respond to oil following a spill. When estimating potential biodegradation rates in the laboratory, high concentrations of inorganic nutrients are often added to prevent nutrient limitation. In this study, we tested the short term response of coastal microbes to fresh diluted bitumen under varying nutrient conditions in a cold water regime. Total hydrocarbon concentrations changed minimally over five days; however, oil composition changed over time and the abundance of microbes increased in all treatments. Addition of phosphate, with or without nitrogen, resulted in rapid changes in community composition, but after three days treatments no longer differed. Nutrients were never depleted in any treatment suggesting that, even at low inorganic nutrient concentrations, microbial communities can quickly respond to hydrocarbons following a spill.Ostvar, S., Iltis, G., Davit, Y., Schlüter, S., Andersson, L., Wood, B.D., Wildenschild, D., 2018. Investigating the influence of flow rate on biofilm growth in three dimensions using microimaging. Advances in Water Resources 117, 1-13. explore how X-ray computed microtomography can be used to generate highly-resolved 3D biofilm datasets on length scales that span multiple pore bodies. The data is integrated into a study of the effects of flow rate on three-dimensional growth of biofilm in porous media. Three flow rates were investigated in model packed-bed columns. Biofilm growth was monitored during an 11-day growth period using a combination of differential pressure and effluent dissolved oxygen measurements. At the end of the growth period, all columns were scanned using X-ray computed microtomography and a barium sulfate-based contrast agent. The resulting images were prepared for quantitative analysis using a novel image processing workflow that was tailored to this specific system. The reduction in permeability due to biofilm growth was studied using both transducer-based pressure drop measurements and image-based calculations using the Kozeny–Carman model. In addition, a set of structural measures related to the spatial distribution of biofilms were computed and analyzed for the different flow rates. We generally observed 1 to 2 orders of magnitude decrease in permeability as a result of bioclogging for all columns (i.e, across flow rates). The greatest average permeability and porosity reduction was observed for the intermediate flow rate (4.5?ml/h). A combination of results from different measurements all suggest that biofilm growth was oxygen limited at the lowest flow rate, and affected by shear stresses at the highest flow rate. We hypothesize that the interplay between these two factors drives the spatial distribution and quantity of biofilm growth in the class of porous media studied here. Our approach opens the way to more systematic studies of the structure-function relationships involved in biofilm growth in porous media and the impact that such growth may have on physical properties such as hydraulic conductivity.Ovalles, C., Moir, M.E., 2018. The Boduszynski Continuum: Contributions to the Understanding of the Molecular Composition of Petroleum. American Chemical Society, p. 250.. Mieczyslaw M. Boduszynski (Mietek) was the recipient of the 2016 George A. Olah Award in Hydrocarbon or Petroleum Chemistry and the 2017 ENFL Distinguished Researcher Award. Dr. Boduszynski was honored for his significant contributions to the understanding of the molecular composition of petroleum and his profound influence on a generation of petroleum and fuel chemists. This book is based on the symposium titled “ENFL Distinguished Researcher Award in Honor of Mieczyslaw M. Boduszynski”, sponsored by the Energy and Fuel Division (ENFL), held at the 253rd ACS National Meeting & Exposition, April 2-6, 2017, in San Francisco. Other authors were invited to participate to complement the multiples technical areas impacted by Boduszynski’s work during his illustrious career.Dr. Boduszynski always advocated that a better understanding of petroleum molecular composition is key to predicting its properties and behavior. Such information is valuable for chemists, geologists, and chemical and petroleum engineers working in all areas of the petroleum value chain from exploration and production to refining. In a demonstration of Mietek’s influence, this book presents an in-depth account of Boduszynski’s work from the point of view of his collaborators and peers. The impacts on operations and current practices in the industry are discussed as well.This monograph covers three broad topics of Mietek’s outstanding career, Heavy Fraction and Asphaltene Characterization, The Boduszynski Continuum Model, and Distillation.Since his days as a graduate student in Poland, Mietek dedicated himself to the understanding of petroleum composition especially that of heavy ends; this means the isolation and characterization of the heaviest portions of the petroleum in a rational and consistent fashion. In Chapter 1, Dr. Michael Moir discusses the origin of the term asphaltene, the history of the science behind, and how the current state of knowledge aligns with the model of petroleum proposed by Boduszynski. In 1980, Dr. Boduszynski caused a considerable stir in his landmark conference publication “Asphaltenes, where are you?” and inspired the title of Dr. Moir’s chapter (Chapter 1) “Asphaltenes, What Art Thou?”.Next, in Chapter 2 Dr. Cesar Ovalles and coworkers present a chapter dedicated to the importance of mass balances (also called material balances) for the understanding of petroleum chemistry and to ensure the successful outcome of experimentation. During his illustrious career, Dr. Mietek Boduszynski devoted considerable time and effort to analyzing and understanding mass balances during his laboratory testing and experimentation. Following his teaching, several case studies are presented for the evaluation of asphaltene dispersants and antifoulants. The primary goal is to show how mass balances were crucial to assess the validity of the new asphaltene determination method, the reliability of the data, and to evaluate the relative effectiveness of the asphaltene-dispersant and antifoulant additives.In Chapter 3, Dr. Estrella Rogel et al. present a series of correlations that link chemical composition with the solubility and thermal behavior of asphaltenes. In the late 80s and early 90s, Dr. Boduszynski used sequential elution fractionation to demonstrate that non-distillable fractions followed the same patterns as distillation cuts and that solubility could be used to perform an equivalent distillation for non-distillable materials. By using new data and some already published in the literature, Rogel and coworkers find that high hydrogen deficiencies and uneven solubility fraction distributions are the main contributors to asphaltene precipitation.Following the footsteps of Boduszynski, in Chapter 4, Dr. Ajit Pradhan et al. describes the latest developments in nuclear magnetic resonance (NMR) to characterize heavy petroleum fractions and heterogeneous catalysts. They use a combination of the extended Brown and Ladner method and surrogate molecules to monitor structural changes resulting from hydroprocessing of petroleum feeds. They also employ Diffusion Ordered Spectroscopy (DOSY) to characterize heavy petroleum fractions and asphaltenes by their size, shape, mass, and charge. Finally, they use Diffusion Ordered Spectroscopy (DOSY) and Dynamic Nuclear Polarization (DNP) to characterize heterogeneous catalysts and heavy petroleum fractions.In Chapter 5, Dr. Francisco Lopez-Linares and co-workers determine vanadium and nickel contents and distributions as a function of boiling point of vacuum gas oil by using High-Temperature Gas Chromatography coupled with Inductively Coupled Plasma Mass Spectrometry (HTGC-ICP-MS). This line of work was inspired by a late-afternoon comment from Dr. Boduszynski to Dr. Michael Moir, “Do you know what we need? We need a method to measure metal distribution versus temperature”. Dr. Moir took up the challenge, and with the help of the glass and machine shops, designed a suitable quartz torch and transfer-line. The rest is history.This brings us to the second broad topic covered in this monograph and perhaps one of the Mietek’s most significant contribution to petroleum chemistry. This topic is called “The Boduszynski Continuum Model.” In his pioneering work, Dr. Boduszynski postulated that petroleum is a continuum of compounds having a wide variety of structural and elemental compositions. The model proposed that, unlike conventional wisdom at the time, petroleum transitions from individual molecules to high molecular weight components (i.e., asphaltenes), and that the molecular composition of petroleum is a continuously variable series of molecules without abrupt transitions. His work in this area forms the basis of the current model of petroleum. He predicted that the high-boiling residue after distillation was, in fact, a continuous extension of low molecular weight components, rather than (as was then thought) high-molecular weight “polymers.” He had great difficulty in getting his ideas published, but has been overwhelmingly vindicated by Fourier Transform Ion Cyclotron Resonance Mass Spectrometry. In Chapter 6, Dr. Ryan Rodgers and co-workers review the work carried out at the National High Magnetic Field Laboratory in the chemical and compositional analysis of petroleum. The material discussed clearly demonstrated the validity of The Boduszynski Continuum Model from the low molecular weight compounds up to asphaltenes. Their results create a molecular-level map with the relationships between carbon number, aromaticity (DBE), heteroatom content, chemical functionality, ring number, asphaltene structures (island and archipelago), and boiling points.In Chapter 7, Lante Carbognani, from the University of Calgary, carries out a literature review on the existence of large molecular weight paraffinic compounds in petroleum streams. He finds that sample handling, diluted conditions, and high set up temperatures are mandatory for the successful characterization of such compounds. Also, he proposes a plausible locus within The Boduszynski Continuum Model for these large molecular weight paraffins within high carbon number (C90-C215 carbon atoms) and low Double Bond Equivalent (DBE <20).In Chapter 8, Dr. Parviz Rahimi reviews the methods for measuring asphaltenes stability and solubility parameters, the factors influencing fouling tendency of crudes due of blending or processing as well as correlations between chemical composition and crude fouling propensity. Dr. Rahimi recognizes from the Boduszynski Continuum Model that one can relate the molecular structure of these complex hydrocarbons to their boiling points. Thus, any changes in the molecular structure of bitumen at the primary stage of conversion to produce synthetic crude would have a significant impact on downstream processing and handling.The last topic covered in this monograph is the broad area of distillation. In this area, Dr. Boduszynski made significant contributions throughout his career. John Carr from the Chevron Energy Technology Company in Richmond was one of Mietek’s closest collaborators during the development of Short-Path Distillation in the decades of the 80s and 90s. John participated in several of Mietek’s projects and remembered that “Mietek, under the assumption that not all crude oils were created equal, was determined to show that many crudes could be fractionated at much higher temperatures than 1000°F and still retain low or minimal metals in the vacuum gas oil.” This fact was not well-known back then. John continued, “Mietek purchased his first short-path (DISTACT) unit from Germany in 1982…He chose six very different varieties of crude oil to start the experiments…. The results were very enlightening, to say the least. Not only did each crude oil behave differently (retaining or losing metals, sulfur components, etc.) at the higher carbon numbers but we were able to fractionate, without thermal cracking, well above 1200°F.” These results and many others formed the basis for the modifications carried out to the refinery distillation units to target a 1050°F cut point rather than the previous 1000°F, with the concomitant increase in refinery margins and profitability. John concluded saying “Many years later at the Opportunity Crude Oil Conference; I learned that other petroleum companies had eventually started using the Short-Path method for this same deep-cut fractionation.”In Chapter 9, Dr. Carl Rechsteiner focuses on the application of Detailed Hydrocarbon Analysis (DHA) for light ends and GC Simulated Distillation (SimDis) for distillable fractions and residuum, and the importance of the composite yield distribution curve obtained from combining these measurements. Many significant learnings can be taken from Dr. Rechsteiner’s work. In line with Mietek’s teaching, one of the most relevant lessons is that the understanding of crude oil composition makes it “easier” to predict and resolve challenges and issues due to the exceedingly complex composition of petroleum.In the last chapter (Chapter 10), Lante Carbognani presents experimental evidence of the existence of thermal cracking affecting both thermogravimetric analysis (TGA) and high temperature simulated distillation. In 1987, this phenomenon was reported in an influential article coauthored by Dr. M. M. Boduszynski during the determination of boiling point distributions based on vacuum TGA. Lante compares TGA and SimDis and develops new correlations to determine and reconcile the differences between these two analytical techniques.Ovalles, C., Rogel, E., Morazan, H., Moir, M.E., 2018. The importance of mass balances: Case studies of evaluation of asphaltene dispersants and antifoulants, in: Ovalles, C., Moir, M.E. (Eds.), The Boduszynski Continuum: Contributions to the Understanding of the Molecular Composition of Petroleum. American Chemical Society, pp. 25-49. enormous complexity associated with the composition of petroleum feedstocks and the nature of their reaction products make material balances almost mandatory for the understating of the chemistry, and eventually successful outcome of the experimentation. Unfortunately, there is considerable lack of mass-balance data available in the literature which prevents us from learning when something is not correct or erroneous, draw the appropriate conclusion for a given experiment, and to understand the chemistry involved in the system. During his illustrious career, Dr. Mietek Boduszynski devoted considerable time and effort to analyzing and understanding the mass balances during his lab testing and experimentation. In this work, several case studies are presented for the use of the on-column filtration/redissolution method at elevated temperatures, in which material balances are shown to be an essential element. Nonylphenol formaldehyde resins, phosphopropoxylated asphaltenes, and commercial products were evaluated as dispersants and antifoulants for asphaltene fractions (C7-insolubles), whole virgin crude oils and hydroprocessed samples. The results showed that mass balances were crucial to assess the validity of the asphaltene determination method, the reliability of the data, and the relative effectiveness of the asphaltene-dispersant and antifoulant additives.Ozaki, H., Nakano, Y., Sakamaki, H., Yamanaka, H., Nakai, M., 2019. Basic eluent for rapid and comprehensive analysis of fatty acid isomers using reversed-phase high performance liquid chromatography/Fourier transform mass spectrometry. Journal of Chromatography A 1585, 113-120. separation of fatty acids, including various isomers, is very important for chemical analyses associated with detailed physiological function investigations. We found that a basic eluent is effective for realizing clear separation of double-bond regioisomers by reversed-phase high-performance liquid chromatography. We carried out a comprehensive analysis of fatty acids, including double-bond positional isomers, trans-fatty acids, and iso-fatty acids using reversed-phase high-performance liquid chromatography coupled with Fourier transform mass spectrometry (LC/FTMS). Clear separation of these fatty acids was achieved using a C18 column and a basic eluent. A three-pump gradient system using acetone provided rapid elution within 22?min. In a single run, 184 fatty acid molecular species contained in a dietary fish oil supplement were detected by the FTMS full scan. A previously unreported peak was also detected, which was assigned as tetratriacontadecaenoic acid by comparison with the MS2 profiles of fatty acids with known chemical structures. This result demonstrates that the developed method is useful for clarifying the composition of fatty acid molecular species in target samples, providing a promising approach to discover unreported fatty acids.Pacheco, A.R., Moel, M., Segrè, D., 2019. Costless metabolic secretions as drivers of interspecies interactions in microbial ecosystems. Nature Communications 10, Article 103. exchange mediates interactions among microbes, helping explain diversity in microbial communities. As these interactions often involve a fitness cost, it is unclear how stable cooperation can emerge. Here we use genome-scale metabolic models to investigate whether the release of “costless” metabolites (i.e. those that cause no fitness cost to the producer), can be a prominent driver of intermicrobial interactions. By performing over 2 million pairwise growth simulations of 24 species in a combinatorial assortment of environments, we identify a large space of metabolites that can be secreted without cost, thus generating ample cross-feeding opportunities. In addition to providing an atlas of putative interactions, we show that anoxic conditions can promote mutualisms by providing more opportunities for exchange of costless metabolites, resulting in an overrepresentation of stable ecological network motifs. These results may help identify interaction patterns in natural communities and inform the design of synthetic microbial consortia.Pain, A., Jenkyns, H.C., Robinson, S.A., Dickson, A.J., O’Brien, C.L., Farnsworth, A., Lunt, D.J., 2019. Southern Hemisphere sea-surface temperatures during the Cenomanian–Turonian: Implications for the termination of Oceanic Anoxic Event 2. Geology 47, 131-134. oceanic anoxic events (OAEs) were major perturbations of the Earth system, associated with high CO2 concentrations in the oceans and atmosphere, high temperatures, and widespread organic-carbon burial. Models for explaining OAEs and other similar phenomena in Earth history make specific predictions about the role and pattern of temperature change, which can be tested through comparison with the geological record. Oceanic Anoxic Event 2 (OAE 2) occurred ～94 m.y. ago and is commonly considered as the type example of an OAE. However, temperature change during this event is constrained largely from Northern Hemisphere sites. In order to understand whether such records represent global patterns, we use an organic geochemical paleothermometer (TEX86) to provide the first detailed Cenomanian–Turonian record of paleotemperatures from the Southern Hemisphere (Ocean Drilling Program Site 1138; paleolatitude of ～47°S). Consideration of this record, Northern Hemisphere records, and general circulation model simulations suggests that global temperatures peaked during OAE 2 but remained high into the early Turonian due to elevated CO2. These results suggest that the burial of organic carbon during the whole of OAE 2 did not, of itself, lead to global cooling and that CO2 remained high into the early Turonian. This climatic evolution suggests that cooling was not the driving mechanism for the termination of OAE 2 and that cessation of widespread anoxic conditions required changes in other factors, such as sea levels, the availability of easily weathered silicate rocks, and/or nutrient sequestration in black shales.Palcu, D.V., Popov, S.V., Golovina, L.A., Kuiper, K.F., Liu, S., Krijgsman, W., 2019. The shutdown of an anoxic giant: Magnetostratigraphic dating of the end of the Maikop Sea. Gondwana Research 67, 82-100., the lost sea of central Eurasia, was an anoxic giant during Oligocene – early Miocene (Maikop Series) times. With a size matching the modern-day Mediterranean Sea and a history of anoxic conditions that lasted for over 20?Myrs, the eastern part of this realm (Black Sea-Caspian Sea domain) holds key records for understanding the build-up, maintenance and collapse of anoxia in marginal seas. Here, we show that the collapse of anoxic Maikop conditions was caused by middle Miocene paleogeographic changes in the Paratethys gateway configuration, when a mid-Langhian (Badenian-Tarkhanian) transgression flooded and oxygenated the Eastern Paratethys. We present an integrated magneto-biostratigraphic framework for the early Middle Miocene (Tarkhanian-Chokrakian-Karaganian regional stages) of the Eastern Paratethys and date the lithological transition from anoxic black shales of the Maikop Series to fossiliferous marine marls and limestones of the regional Tarkhanian stage. For this purpose, we selected two long and time-equivalent sedimentary successions, exposed along the Belaya and the Pshekha rivers, in the Maikop type area in Ciscaucasia (southern Russia). We show that a significant but short marine incursion took place during the Tarkhanian, ending the long-lasting Maikop anoxia of the basin. Our magnetostratigraphic results reveal coherent polarity patterns, which allow a straightforward correlation with the time interval 15–12?Ma of the Geomagnetic Polarity Time Scale. The Tarkhanian flooding occurred during a relatively short normal polarity interval that correlates with C5Bn, resulting in an age of 14.85?Ma. The regional Tarkhanian/Chokrakian stage boundary is located within C5ADn at an age of 14.75?Ma and the Chokrakian/Karaganian boundary is tentatively correlated with C5ACn and an age of 13.9–13.8?Ma. Our new Tarkhanian flooding age reveals a paleogeographic scenario that is different from many previous reconstructions. Instead of envisaging marine connections to the Indian Ocean, we show that major changes in connectivity between the Eastern and Central Paratethys seas have caused the influx of marine waters during the Tarkhanian. An increase in marine connectivity with the Mediterranean during a short episode of rapid sea-level rise triggered mixing and ended the widespread anoxia in the Eastern Paratethys. The mixing episode was short-lived (~100?kyr) as the sea-level rise slowed down and connectivity degraded because of tectonic uplift in the gateway area.Panagiotopoulos, C., Pujo-Pay, M., Benavides, M., Van Wambeke, F., Sempéré, R., 2019. The composition and distribution of semi-labile dissolved organic matter across the southwest Pacific. Biogeosciences 16, 105-116. distribution and dynamics of dissolved organic carbon (DOC) and dissolved combined neutral sugars (DCNS) were studied across an increasing oligotrophic gradient (18 to 22°?S latitude) in the tropical South Pacific Ocean, spanning from the Melanesian Archipelago (MA) area to the western part of the South Pacific gyre (WGY), in austral summer as a part of the OUTPACE project. Our results show that DOC and DCNS concentrations exhibited no statistical differences between the MA and WGY areas (0–200?m: 47–81??M?C for DOC and 0.2-4.2??M?C for DCNS). However, due to a deepening of the euphotic zone, a deeper penetration of DOC was noticeable at 150?m of depth at the WGY area. Excess DOC (DOCEX) was determined as the difference between surface and deep-sea DOC values, and euphotic zone integrated stocks of both DOC and DOCEX were higher in the WGY than the MA area. Considering DOCEX as representative of semi-labile DOC (DOCSL), its residence time was calculated as the ratio of DOCSL to bacterial carbon demand (BCD). This residence time was 176±43 days (n=3) in the WGY area, about 3 times longer than in the MA area (T r =51±13 days, n=8), suggesting an accumulation of semi-labile dissolved organic matter (DOM) in the surface waters of WGY. Average epipelagic (0–200?m) DCNS yields (DCNS?×?DOC?1) based on volumetric data were roughly similar in both areas, accounting for ～2.8?% of DOC. DCNS exhibited a longer residence time in WGY (T r =91±41 days, n=3) than in MA (T r =31±10 days, n=8), further suggesting that this DCNS pool persists longer in the surface waters of the WGY. The accumulation of DOCEX in the surface waters of WGY is probably due to very slow bacterial degradation due to nutrient and/or energy limitation of heterotrophic prokaryotes, indicating that biologically produced DOC can be stored in the euphotic layer of the South Pacific gyre for a long period.Pandey, A., Chang, J.-S., Soccol, C.R., Lee, D.-J., Chisti, Y., 2019. Biofuels from Algae. Sustainable Platform for Fuels, Chemicals and Remediation, 2nd Edition, Biomass, Biofuels and Biochemicals. Elsevier, p. 603., Biofuels and Biochemicals: Biofuels from Algae, Second Edition provides information on strategies for commercial microalgae based biofuel production, including their cultivation, pre-treatment and conversion methods. The book discusses methods for producing microalgal biomass in large scale by outdoor culturing and outlines new technologies for their use. In addition, it explains how modern genetic engineering enables the generation of recombinant strains that generate higher quantities of feedstock. The complete utilization of microalgal biomass, which can also be obtained from valorizing nutrients from wastewater and industrial exhaust gases, can be efficiently converted to energy rich biofuels and high value pharmaceuticals in a well-defined biorefinery.Key FeaturesIncludes the current technologies for the cultivation and conversion of energy rich microalgal biomass into biofuelsProvides information on all the conversion methods – biochemical and thermochemical conversionsCovers other high value products from microalgae and less conventional applications, such as fine chemical production and aviation fuel generationDiscusses the economics of microalgal biofuel production and how to accomplish cost competitive resultsChapter 1 - Introduction to algal fuels, Yusuf Chisti, Pages 1-31Chapter 2 - Culture media for mass production of microalgae, Júlio Cesar de Carvalho, Eduardo Bittencourt Sydney, Lorenzo Ferrari Assú Tessari?, Carlos Ricardo Soccol, Pages 33-50Chapter 3 - Microalgal strain selection for biofuel production. Eduardo Bittencourt Sydney, Alessandra Cristine Novak Sydney, Júlio Cesar de Carvalho, Carlos Ricardo Soccol, Pages 51-66Chapter 4 - Potential carbon fixation of industrially important microalgae, Eduardo Bittencourt Sydney, Alessandra Cristine Novak Sydney, Júlio Cesar de Carvalho, Carlos Ricardo Soccol, Pages 67-88Chapter 5 - Metabolic engineering and molecular biotechnology of microalgae for fuel production, Su-Chiung Fang, Pages 89-107Chapter 6 - Nutrient recycling for sustainable production of algal biofuels, Giorgos Markou and Florian Monlau, Pages 109-133Chapter 7 - Algal biomass harvesting and drying, Kuan-Yeow Show, Yue-Gen Yan and Duu-Jong Lee, Pages 135-166Chapter 8 - Algal culture and biofuel production using wastewater, Shih-Hsin Ho, Yi-Di Chen, Wen-Ying Qu, Fei-Yu Liu, Yue Wang, Pages 167-198Chapter 9 - Open pond systems for microalgal culture, Jorge Alberto Vieira Costa, Bárbara Catarina Bastos Freitas, Thaisa Duarte Santos, Bryan Gregory Mitchell, Michele Greque Morais, Pages 199-223Chapter 10 - Design of photobioreactors for algal cultivation, Hong-Wei Yen, I-Chen Hu, Chun-Yen Chen, Dillirani Nagarajan, Jo-Shu Chang, Pages 225-256Chapter 11 - Flocculation and electroflocculation for algal biomass recovery, Tawan Chatsungnoen and Yusuf Chisti, Pages 257-286Chapter 12 - Algal oils as biodiesel, S. Venkata Mohan, M.V. Rohit, G. Venkata Subhash, Rashmi Chandra, M. Prathima Devi, Sai Kishore Butti, K. Rajesh, Pages 287-323Chapter 13 - Biohydrogen production from algae: Perspectives, challenges, and prospects, Kuan-Yeow Show, Yue-Gen Yan and Duu-Jong Lee. Pages 325-343Chapter 14 - Production of potential coproducts from microalgae, I-Chen Hu, Pages 345-358Chapter 15 - Jet biofuels from algae, Gregory W. O’Neil, Gerhard Knothe and Christopher M. Reddy, Pages 359-395Chapter 16 - Algal spent biomass—A pool of applications, A. Catarina Guedes, Helena M. Amaro, Isabel Sousa-Pinto, F. Xavier Malcata, Pages 397-433Chapter 17 - Hydrothermal upgradation of algae into value-added hydrocarbons, Bijoy Biswas and Thallada Bhaskar, Pages 435-459Chapter 18 - Production of biofuels from algae biomass by fast pyrolysis, Carlos José Dalmas Neto, Luiz Alberto Junior Letti, Susan Grace Karp, Francisco Menino Destéfanis Vítola, Carlos Ricardo Soccol, Pages 461-473Chapter 19 - Scale-up and commercialization of algal cultivation and biofuels production, Man Kee Lam, Choon Gek Khoo and Keat Teong Lee, Pages 475-506Chapter 20 - Life-cycle assessment of microalgal-based biofuel, Marjorie Morales, Pierre Collet, Laurent Lardon, Arnaud Hélias, Jean-Philippe Steyer, Olivier Bernard, Pages 507-550Chapter 21 - Costs analysis of microalgae production, F.G. Acién Fernández, José María Fernández Sevilla and Emilio Molina Grima, Pages 551-566Index, Pages 567-579Pandey, R., Harpalani, S., 2019. Impact of bioconversion on matrix strain response of coal reservoirs: Part 1-Experimental insights. Fuel 239, 1363-1375. technical feasibility of commercial gas production from microbially enhanced coalbed methane (MECBM) reservoirs can be divided into two broad categories: microbial treatment procedures and reservoir suitability. At this time, studies investigating the changes in reservoir-scale properties of coal as a result of bioconversion are lacking. This paper, first of a two-part series, presents the experimental work aimed at investigating the changes in sorption-induced strain response of coal to helium and methane flooding as a result of bioconversion. The strain and its variation, critical to producing methane after bioconversion, were established for coal treated for three periods, 15, 30 and 60?days. The results indicated a softer coal post-bioconversion which, in turn, resulted in inelastic strain with initial helium injection. However, past this initial compression, the bioconverted coal behavior was similar to untreated coal during continued helium injection/depletion. Methane flooding resulted in decreased sorption-induced shrinkage post-treatment, the decrease in Langmuir pressure and volume constants becoming larger with continued treatment. The observed results were used to understand the changes in coal structure for production of biogenic coalbed methane (BCBM) from depleted CBM reservoirs, recharged with methane using the bioconversion technology. The second part presents a detailed analysis of the experimental results to evaluate the behavior and performance of BCBM reservoirs.Pandey, R., Harpalani, S., 2019. Impact of bioconversion on matrix strain response of coal reservoirs: Part 2-Reservoir insights. Fuel 239, 1376-1387. data obtained for the strain response of coal to helium and methane flooding, pre-and post-bioconversion, was used to evaluate the reservoir-scale implications of coal bioconversion. Analysis showed that reservoir parameters, Langmuir-type strain (??l) and pressure (?P?), rebound (Prb) and recovery (Prc) pressures decreased post-bioconversion non-linearly with the volume of biogenic methane produced. Also, the solid-matrix compressibility (CS) increased and shrinkage/swelling (Cm) compressibility decreased post-bioconversion. The effective stress and permeability response of coal to depletion was suppressed after microbial treatment. Finally, bioconversion resulted in softening of the coal matrix as well as ‘excess’ volumetric shrinkage post-methane depletion, enhancing the reservoir permeability. However, the increase was insignificant and was overshadowed by the effect of bioconversion induced swelling, which resulted in a significant reduction in reservoir permeability. The non-linear dependence of Cm to pore pressure resulted in its rebound past an inflection pressure (PI), identifiable for coal treated for longer durations. This was used to define an ideal condition, beyond which there was some improvement in reservoir performance. Effective stress response of coals before and after treatment was then used to rate the suitability of coals to bioconversion from a reservoir perspective.Pang, T.Y., Lercher, M.J., 2019. Each of 3,323 metabolic innovations in the evolution of E. coli arose through the horizontal transfer of a single DNA segment. Proceedings of the National Academy of Sciences 116, 187.: Bacteria often evolve by copying genes from other strains, a process termed horizontal gene transfer. As a consequence, different strains of the bacterial species Escherichia coli differ substantially in the sets of genes they possess. Here, we use the inferred gene sets of all recent ancestors of 53 E. coli strains to reconstruct the ancestors’ abilities to grow in different nutritional environments. This allows us to infer over 3,000 metabolic innovations in E. coli’s evolutionary history. All innovations arose through the copying (transfer) of only one small piece of DNA from another strain, demonstrating an amazing capacity of E. coli to quickly adapt to new environments.Abstract: Even closely related prokaryotes often show an astounding diversity in their ability to grow in different nutritional environments. It has been hypothesized that complex metabolic adaptations—those requiring the independent acquisition of multiple new genes—can evolve via selectively neutral intermediates. However, it is unclear whether this neutral exploration of phenotype space occurs in nature, or what fraction of metabolic adaptations is indeed complex. Here, we reconstruct metabolic models for the ancestors of a phylogeny of 53 Escherichia coli strains, linking genotypes to phenotypes on a genome-wide, macroevolutionary scale. Based on the ancestral and extant metabolic models, we identify 3,323 phenotypic innovations in the history of the E. coli clade that arose through changes in accessory genome content. Of these innovations, 1,998 allow growth in previously inaccessible environments, while 1,325 increase biomass yield. Strikingly, every observed innovation arose through the horizontal acquisition of a single DNA segment less than 30 kb long. Although we found no evidence for the contribution of selectively neutral processes, 10.6% of metabolic innovations were facilitated by horizontal gene transfers on earlier phylogenetic branches, consistent with a stepwise adaptation to successive environments. Ninety-eight percent of metabolic phenotypes accessible to the combined E. coli pangenome can be bestowed on any individual strain by transferring a single DNA segment from one of the extant strains. These results demonstrate an amazing ability of the E. coli lineage to adapt to novel environments through single horizontal gene transfers (followed by regulatory adaptations), an ability likely mirrored in other clades of generalist bacteria.Papakosta, V., Oras, E., Isaksson, S., 2019. Early pottery use across the Baltic – A comparative lipid residue study on Erteb?lle and Narva ceramics from coastal hunter-gatherer sites in southern Scandinavia, northern Germany and Estonia. Journal of Archaeological Science: Reports 24, 142-151. Late Mesolithic Erteb?lle and Narva cultures (6th – 5th/4th millennium BC) in the southwest and eastern Baltic, respectively, shared similar vessel types, namely pointed-based pots and oval bowls. As a consequence, this phenomenon raised questions about inter-cultural connections across the Baltic and possible influence for the production of pottery from the Narva to the Erteb?lle hunter-gatherers. Whereas the two pottery traditions were shown to be different with regards to raw materials and manufacture, in this study we further attempt a comparison on the basis of function using a lipid residue analysis approach. The aim is to examine whether typological analogies were based on common functional requirements. This paper presents new evidence for the use of Erteb?lle ceramics in the southwest Baltic from the analysis of pottery samples from a number of coastal sites in southern Sweden (Scania) and eastern Denmark (Lolland). Gas chromatography-mass spectrometry (GC–MS) and gas chromatography-combustion-isotope ratio mass spectrometry (GC-c-IRMS) analysis were performed on the absorbed lipid residues to determine their structural characteristics and the stable carbon isotopic composition of selected fatty acids. Results are discussed and compared with analogous published data of Narva ceramics from Estonia. Data from other coastal sites in Denmark and northern Germany are also included for wider comparison. Based on our findings, we conclude that despite little variability in the isotope values of residues, Erteb?lle and Narva pots did not serve the same functional demands, and different motives led to their production. Whilst the Narva ceramics appear to have had a specialized role in processing aquatic products, the Erteb?lle were more multi-purpose vessels, used also for terrestrial animal and plant resources.Pasquier, V., Toucanne, S., Sansjofre, P., Dixit, Y., Revillon, S., Mokeddem, Z., Rabineau, M., 2019. Organic matter isotopes reveal enhanced rainfall activity in Northwestern Mediterranean borderland during warm substages of the last 200 kyr. Quaternary Science Reviews 205, 182-192. this study we use bulk sediment organic matter stable isotopes (δ13Corg and δ15N) to examine the nature and timing of preserved organic matter in borehole PRGL1-4 from Northwestern Mediterranean Sea. This region is known as a transitional zone between the North Atlantic atmospheric circulation and the North African monsoon system. In the Gulf of Lion (SE France), increased inputs of organic matter from sediment-laden rivers occurred during warm substages of the last 200 kyr (MIS 5e, 5c, and 5a; MIS 6d, and 6b). Increased terrestrial organic matter are inferred from organic carbon isotopic composition (δ13Corg), and are interpreted as resulting from enhanced rainfall over the Rhone river catchment area. Such increase in terrestrial organic carbon induced enhancement of the primary productivity leading to the formation of local oxygen minimum zone as demonstrated by ～3‰ values in δ15N. Comparison with regional paleohydrological records from the northern Mediterranean borderlands reveals the regional character of these pluvial events. Taking advantage of the location of PRGL1-4 borehole, out of Mediterranean cyclogenesis area, we suggest that the pluvial events recorded during warm substages of the last 200 kyr occurred in response to enhanced passage of North Atlantic atmospheric perturbation over the Gulf of Lion catchment area (especially over Rhone river watershed which represent 80% of the GoL catchment area), a scenario possibly similar to that encountered today during negative- NAO like conditions. At a regional scale, our data suggests that high rainfall events over the Gulf of Lion catchement area and the Rhone watershed occurred at the time of North African summer monsoon and the sapropel deposition in the Mediterranean basin, thus highlighting a close coupling between mid- (North Atlantic) and low-latitudes (monsoon) climate systems. Importantly, our geochemical evidence from the Gulf of Lion support an extra-Mediterranean source for the regional pluvial events described in many paleoclimatic records from the northern Mediterrean borderlands during warm substages of the last climate cycles. Consequently, we suggest that this region as a whole could provide, in addition to the river runoff from the North African sector, the necessary conditions for the sapropel deposition.Patel, S., Homaei, A., Patil, S., Daverey, A., 2019. Microbial biosurfactants for oil spill remediation: pitfalls and potentials. Applied Microbiology and Biotechnology 103, 27-37. of fossil-based oils during their conveyance through water conduits are sporadic, but significant environmental disasters. As the viscous hydrocarbons of the crude oils spread on water surface and choke aquatic life to death, their effective degradation is crucial for ecological balance. Though chemical and mechanical means are conventional ways to tackle the issues, they are riddled with limitations. In this scenario, coercing the biosurfactant-producing bacteria and fungi are promising avenues. Biosurfactants, the amphiphilic compounds, are capable of reducing interfacial tension, dispersing the oil particles, and degrading them?into non-toxic debris. Among the vast array of biosurfactants, the trio of rhamnolipid, sophorolipid, and surfactin have been characterized well. Among the microbes, only Pseudomonas, Bacillus, and Candida have been evaluated, while there can be other exploitable candidates. In this regard, this review discusses the scopes and hurdles in utilization of the microbial surface-active compounds for oil spill management.Patel, S., Majumder, S.K., 2018. Prediction of transient pressure change during natural gas hydrate formation. Petroleum Science and Technology 36, 1820-1828. increasing demand for fossil fuels and diminishing natural energy reserves have necessitated the exploration of gas hydrates. Gas hydrates find importance in oil and gas industries where the formation and dissociation of gas hydrate become important. Thus, the proper understanding of formation, decomposition and properties of gas hydrates is a required. In this work, a macroscopic kinetic model is analyzed and modified to predict the pressure change with time during the hydrate formation based on the chemical affinity of compounds. With the help of experimental data, the degree of parity of the modified and unmodified models are explained. The dependency of the chemical affinity of the gas hydrate reformers is explained based on the kinetic model validation with the experimental results. The modified model predict the transient pressure during gas hydrate formation with an average absolute error of 3.6%.Peng, C., Mao, S., Hu, J., He, L., 2019. A Helmholtz free energy equation of state for the vapor-liquid equilibrium and PVTx properties of the H2S–H2O mixture and its application to the H2S-H2O- NaCl system. Applied Geochemistry 101, 19-30. equation of state (EOS) explicit in Helmholtz free energy has been developed to calculate the vapor-liquid equilibrium (VLE) and pressure-volume-temperature-composition (PVTx) properties of the H2S–H2O fluid mixture. This EOS, where five mixing parameters are used, is based on the highly accurate EOSs of pure H2S and H2O fluids, and contains a simple departure function. Compared to reliable experimental data available, the average absolute deviations of H2S solubility in liquid phase, water content in vapor phase, and liquid density of the H2S–H2O system are 3.88%, 5.03% and 0.20%, respectively. The EOS of the H2S–H2O fluid mixture, together with the Pitzer activity coefficient of H2S in aqueous NaCl solution from previous study, can be used to predict the H2S solubility in aqueous NaCl solution with an average absolute deviation of 7.52%. The water content of vapor phase in the H2S–H2O–NaCl system can be reproduced with the fluid EOS of H2S–H2O system by a fugacity-activity method within experimental uncertainties. The fluid EOS of H2S–H2O system, combined with the Helmholtz free energy EOS of H2O–NaCl fluid mixture, can predict the PVTx properties of the H2S–H2O–NaCl mixture without using additional mixing parameters. The developed EOS can be safely used under the conditions of CO2 capture and sequestration (273–473?K, 0–400?bar and 0–6?mol?kg?1), beyond which the EOS also has some extrapolated ability. The computer codes are in the supplemental data and can be downloaded from Applied Geochemistry or obtained from the corresponding author.Peng, T., Luo, A., Kan, J., Liang, L., Huang, T., Hu, Z., 2018. Identification of A ring-hydroxylating dioxygenases capable of anthracene and benz[a]anthracene oxidization from Rhodococcus sp. P14. Journal of Molecular Microbiology and Biotechnology 28, 183-189., contamination of soil and marine sediments by polycyclic aromatic hydrocarbons (PAHs) has become a serious problem all over the world. Rhodococcus sp. P14 was isolated from sediments with crude oil contaminate and showed degradation ability on various PAHs. The genome of Rhodococcus sp. P14 was sequenced. A gene cluster encoding a ring-hydroxylating dioxygenase Baa related to PAH degradation was identified by bioinformatics. The expression level of gene baaA was increased when P14 was cultured with anthracene, pyrene, phenanthrene, or benz[a]anthracene as the single carbon source. The recombinant protein Baa was overexpressed in E. coli BL21 (DE3). Further investigations on the recombinant protein Baa in E. coli demonstrated that it was able to oxidize anthracene and benz [a]anthracene, resulting in 9,10-dihydroxyanthracene and 7, 12-dihydroxybenz[a]anthracene as metabolites, respectively. These results indicate that Baa plays an important role in PAH degradation in Rhodococcus sp. P14 and Baa has potential application in the bioremediation of PAHs in the contaminated environment.Pennisi, E., 2019. Did neurons arise from an early secretory cell? Science 363, 212-213. through the oceans, voraciously consuming plankton and other small creatures—and occasionally startling a swimmer—the beautiful gelatinous masses known as comb jellies won't be joining Mensa anytime soon. But these fragile creatures have nerve cells—and they offer insights about the evolutionary origins of all nervous systems, including our own. Inspired by studies of a glue-secreting cell unique to these plankton predators, researchers have now proposed that neurons emerged in the last common ancestor of today's animals—and that their progenitors were secretory cells, whose primary function was to release chemicals into the environment.Joseph Ryan, a computational evolutionary biologist the University of Florida Whitney Laboratory for Marine Bioscience in St. Augustine, suggested that scenario last year after tracing the development of nerve cells in embryos of comb jellies, among the most ancient animals. Earlier this month at the annual meeting of the Society for Integrative and Comparative Biology (SICB) here, he marshaled evidence from developmental studies of other animals, all pointing to common origins for some neuron and secretory cells.“What Ryan is proposing is novel and important,” says David Plachetzki, an evolutionary biologist at the University of New Hampshire in Durham. Among other mysteries, it could resolve a long debate about whether the nervous system evolved twice early in animal life.Today, nerve cells are among the most specialized cell types in the body, able to transmit electrical signals, for example. Some versions talk to each other, others relay information from the environment to the brain, and still more send directives to muscles and other parts of the body. They are an almost universal feature of animals; only sponges and placozoans, an obscure group of tiny creatures with the simplest of animal structures, lack them.When and how the animal nervous system arose has remained murky, however. Ryan and Whitney lab postdoctoral fellow Leslie Babonis were drawn into the debate by their recent analysis of the developmental origin of the colloblast, a specialized cell unique to most comb jellies. Studding the tentacles of comb jellies, the cells secrete glue that grabs passing prey.By tracing the development of individual cells in comb jelly embryos and monitoring each cell's gene activity, Babonis discovered that colloblasts arise from the same progenitor cells as the animal's nerve cells. “That was not expected at all,” recalls Ryan, whose team published those results on 30 August 2018 in Molecular Biology and Evolution.Since then, however, he's learned of additional studies pointing to common origins for neurons and other secretory cells in embryonic development—and perhaps in evolution. In his talk at the SICB meeting, he noted that one team showed more than 25 years ago that the stinging cells of jellyfish, another specialized secretory cell type, arise from the same embryonic precursors as the animal's nerve cells. He cited similar evidence for hydra and fruit flies. “It's a really generalizable thing,” he says.The finding could settle a long-standing debate. In 2013, a research team analyzing the newly sequenced genome of a comb jelly known as the sea gooseberry (Pleurobrachia bachei) discovered it was missing multiple genes active in the nervous systems of most animals: certain Hox genes, which control development, and the gene for the neurotransmitter serotonin. That discovery led the team to propose that comb jellies evolved a nervous system independently from almost all other animals (Science, 25 January 2013, p. 391). But many wondered how something so complex could have evolved twice.Finding a common developmental source for neurons in comb jellies, jellyfish, and many other animals suggests it didn't, Ryan and others now say. The work shows “the platform upon which the nervous system was built was there” in the last common ancestor of animals, says Timothy Jegla, a neurobiologist at Pennsylvania State University in University Park. “Relatively simple reprogramming [of ] stem cells during development can lead to whole new cell types and tissues, and the nervous system is probably just another example of that.” Other researchers, however, say it's still possible that nerve cells had multiple origins after the last common ancestor, each time arising from the same stem cell lineage.Next, Ryan, Babonis, and Whitney lab neurophysiologist Yuriy Bobkov hope to learn how progenitor cells develop into neurons by studying a simple sensory organ—the “warts” of the warty comb jelly, or sea walnut (Mnemiopsis leidyi). Recent work shows that each wart contains about 500 nerve and muscle cells that react to light, the smell of fish, and mechanical stimuli. Warts regenerate if cut off, and by tracing gene activity of their cells as they regrow and specialize, Ryan hopes his team can pin down the genes directing nerve cell formation—and perhaps, he says, “peel back some of the complexity of the evolution of neurons.”Peoples, L.M., Norenberg, M., Price, D., McGoldrick, M., Novotny, M., Bochdansky, A., Bartlett, D.H., 2019. A full-ocean-depth rated modular lander and pressure-retaining sampler capable of collecting hadal-endemic microbes under in situ conditions. Deep Sea Research Part I: Oceanographic Research Papers 143, 50-57. hadal zone remains one of the least studied environments because of its inaccessibility, in part because of hydrostatic pressures extending to 110?MPa. Few instruments are capable of sampling from such great depths. We have developed a full-ocean-depth-capable lander that can be fit with sampling packages for the collection of still images, video, motile megafauna, and hadal seawater. One payload includes a pressure-retaining sampler (PRS) able to maintain seawater samples under in situ pressure during recovery. We describe the technical specifications of the lander and the PRS and preliminary results from three deployments at depths in excess of 10,700?m in the Mariana Trench. Seawater from full-ocean depth was recovered at 81% of the in situ pressure. This facilitated the collection of microbial genomes affiliated with the family Flavobacteriaceae within the Bacteroidetes and the phylum Marinimicrobia. We show that these microbes are specifically enriched in hadal zones, representing novel trench lineages, and describe their adaptations for living in hadal environments. These findings highlight the utility of this lander system, which facilitates scientific inquiry at depths greater than 6000?m.Pereira, L.S., Arz, H.W., P?tzold, J., Portilho-Ramos, R.C., 2018. Productivity evolution in the South Brazilian Bight during the last 40,000?years. Paleoceanography and Paleoclimatology 33, 1339-1356. productivity largely controls the oceanic uptake of atmospheric carbon dioxide and contributed to the global climate changes that led to the termination of the last glacial cycle. Past changes in marine productivity were presumably associated with disturbances in the Atlantic meridional overturning circulation (AMOC). In the South Atlantic, however, the evolution of marine productivity throughout the last glacial?interglacial cycle is still poorly constrained mainly due to the scarcity of records with high temporal resolution. Here we present high-resolution records of paleoproductivity and upper-water-column properties from the western subtropical South Atlantic covering the last 40,000?years. Our records are based on faunal and stable oxygen isotopic analyses of planktonic foraminifera from a marine sediment core collected from an upwelling region off southeastern South America (27°S). We used the relative abundance of eutrophic planktonic foraminifera (i.e., Globigerinita glutinata and Globigerina bulloides) as proxies of primary productivity. Our findings reveal, for the first time, enhanced primary productivity during Heinrich Stadials along the last glacial, when the AMOC showed reduced strength. Additionally, our results reveal decreased primary productivity over the Last Glacial Maximum, a period of markedly lower sea level; and the Younger Dryas, when the AMOC showed only moderate reductions. The most outstanding productivity decline, however, is depicted at the onset of the Holocene, when the AMOC recovers its strength. We hypothesize that the observed changes were triggered by the dynamics of the Brazil Current primarily driven by disturbances in the AMOC.Peters, K.E., Lillis, P.G., Lorenson, T.D., Zumberge, J.E., 2019. Geochemically distinct oil families in the onshore and offshore Santa Maria basins, California. American Association of Petroleum Geologists Bulletin 103, 243-271. purpose of this work is to identify genetic affinities among 48 crude oil samples from the onshore and offshore Santa Maria basins. A total of 21 source-related biomarker and stable carbon isotope ratios among the samples were assessed to assure that they were unaffected by secondary processes. Chemometric analysis of these data identifies six oil families with map and stratigraphic distributions that reflect organofacies variations within the Miocene Monterey Formation source rock. The data comprise a training set that was used to create a chemometric decision tree to classify newly collected oil samples. Three onshore families originated from two synclines, which may contain one or more pods of thermally mature source rock. Multiple biomarker parameters indicate that the six oil families achieved early oil window maturity in the range of 0.6%–0.7% equivalent vitrinite reflectance. The offshore oil samples consist of one family from Point Pedernales field and two families from the “B” prospect. Geochemical characteristics of these families indicate origins under differing water column and sediment oxicity and carbonate versus siliceous and detrital input in ‘carbonate,’ ‘marl,’ and ‘shale’ organofacies like those in the lower calcareous–siliceous, carbonaceous marl, and clayey–siliceous members of the Monterey Formation elsewhere in coastal California. The corresponding lithofacies and organofacies appear to be linked to the early–middle Miocene climate optimum and subsequent paleoclimatic cooling after circa 14 Ma, a systematic up-section increase in the stable carbon isotope composition of related oil samples, decreased preservation of calcium carbonate shells from planktic foraminifera and coccoliths, and increased preservation of clay-sized siliceous shells of diatoms and radiolarians. The results show that organofacies within the Monterey source rock are responsible for many of the geochemical differences between the oil families. This paleoclimate–organofacies model for crude oil from the Monterey Formation can be used to enhance future exploration efforts in many areas of coastal California.Petr, M., P??bo, S., Kelso, J., Vernot, B., 2019. Limits of long-term selection against Neandertal introgression. Proceedings of the National Academy of Sciences 116, 1639-1644.: Since the discovery that all non-Africans inherit 2% of their genomes from Neandertal ancestors, there has been a great interest in understanding the fate and effects of introgressed Neandertal DNA in modern humans. A number of recent studies have claimed that there has been continuous selection against introgressed Neandertal DNA over the last 55,000 years. Here, we show that there has been no long-term genome-wide removal of Neandertal DNA, and that the previous result was due to incorrect assumptions about gene flow between African and non-African populations. Nevertheless, selection did occur following introgression, and its effect was strongest in regulatory regions, suggesting that Neandertals may have differed from humans more in their regulatory than in their protein-coding sequences.Abstract: Several studies have suggested that introgressed Neandertal DNA was subjected to negative selection in modern humans. A striking observation in support of this is an apparent monotonic decline in Neandertal ancestry observed in modern humans in Europe over the past 45,000 years. Here, we show that this decline is an artifact likely caused by gene flow between modern human populations, which is not taken into account by statistics previously used to estimate Neandertal ancestry. When we apply a statistic that avoids assumptions about modern human demography by taking advantage of two high-coverage Neandertal genomes, we find no evidence for a change in Neandertal ancestry in Europe over the past 45,000 years. We use whole-genome simulations of selection and introgression to investigate a wide range of model parameters and find that negative selection is not expected to cause a significant long-term decline in genome-wide Neandertal ancestry. Nevertheless, these models recapitulate previously observed signals of selection against Neandertal alleles, in particular the depletion of Neandertal ancestry in conserved genomic regions. Surprisingly, we find that this depletion is strongest in regulatory and conserved noncoding regions and in the most conserved portion of protein-coding sequences.Philips, J., Monballyu, E., Georg, S., De?Paepe, K., Prévoteau, A., Rabaey, K., Arends, J.B.A., 2019. An Acetobacterium strain isolated with metallic iron as electron donor enhances iron corrosion by a similar mechanism as Sporomusa sphaeroides. FEMS Microbiology Ecology 95, Article fiy222. sphaeroides related strains are to date the only homoacetogens known to increase metallic iron corrosion. The goal of this work was to isolate additional homoacetogenic bacteria capable of using Fe(0) as electron donor and to explore their extracellular electron transfer mechanism. Enrichments were started from anoxic corrosion products and yielded Acetobacterium as main homoacetogenic genus. Isolations were performed with a new procedure using plates with a Fe(0) powder top layer. An Acetobacterium strain, closely related to A. malicum and A. wieringae, was isolated, in addition to a S. sphaeroides strain. The Acetobacterium isolate significantly increased Fe(0) corrosion ((1.44 ± 0.16)-fold) compared to abiotic controls. The increase of corrosion by type strains ranged from (1.28 ± 0.13)-fold for A. woodii to (2.03 ± 0.22)-fold for S. sphaeroides. Hydrogen mediated the electron uptake from Fe(0) by the acetogenic isolates and tested type strains. Exchange of the medium and SEM imaging suggested that cells were attached to Fe(0). The corrosion enhancement mechanism is for all tested strains likely related to free extracellular components catalyzing hydrogen formation on the Fe(0) surface, or to the maintenance of low hydrogen concentrations on the Fe(0) surface by attached cells thereby thermodynamically favoring hydrogen formation.Piga, I., Heijs, B., Nicolardi, S., Giusti, L., Marselli, L., Marchetti, P., Mazzoni, M.R., Lucacchini, A., McDonnell, L.A., 2019. Ultra-high resolution MALDI-FTICR-MSI analysis of intact proteins in mouse and human pancreas tissue. International Journal of Mass Spectrometry 437, 10-16. assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) of intact proteins is mostly performed using time-of-flight (TOF) based mass spectrometers, operated in linear mode. Linear MALDI-TOF systems provide limited mass resolving power and mass accuracy, which complicates assigning identities to the peaks in the MSI datasets. In this work we report ultra-high mass resolution MALDI-MSI based on 15T Fourier transform ion cyclotron resonance (FTICR) mass spectrometry for the analysis of intact proteins directly from non-embedded and OCT-embedded mouse and human (control and type 2 diabetes) pancreas so that small endocrine compartments (islets of Langerhans) may be analyzed in control and pathological tissues. Sample preparation methods, in terms of increased sensitivity while limiting lateral diffusion of analytes, have been investigated. By combining protein localization, high mass accuracy, and the clearly resolved isotope patterns we were able to assign protein identities with additional confidence, including proteins of similar average mass and with interspersed isotopomers. These capabilities allowed us to ascertain the presence of many protein adducts that, with a low resolving power instrument, could be misinterpreted as distinct protein ions.Pinto da Costa, J., Reis, V., Pa?o, A., Costa, M., Duarte, A.C., Rocha-Santos, T., 2019. Micro(nano)plastics – Analytical challenges towards risk evaluation. TrAC Trends in Analytical Chemistry 111, 173-184. quantification of micro- and nanoplastics in environmental matrices is an analytical challenge and pushes to the use of unrealistic high exposure concentrations in laboratory studies which can lead to manifestations of ecotoxicological effects and risks estimation that are transient under natural conditions. Moreover, in field studies, it is difficult to compare the data obtained due to the lack of sampling protocols, standardized methodologies and techniques for the identification and quantification of micro- and nanoplastics, owing to the inherent physical characteristics of the these materials. Also, the definition of exposure limits is difficult due to the challenge of analytical methodologies. Therefore, this paper aims to characterize the existent analytical challenges in each step from isolation to quantification of nano- and microplastics and their consequences in the estimation of risks.Pirok, B.W.J., Stoll, D.R., Schoenmakers, P.J., 2019. Recent developments in two-dimensional liquid chromatography: Fundamental improvements for practical applications. Analytical Chemistry 91, 240-263. chromatography (LC) is an incredibly successful analytical separation tool. Its versatility is unprecedented because of the many different separation modes (reversed-phase LC, ion-exchange chromatography, size-exclusion chromatography, etc.) and because almost all samples can be dissolved in some kind of solvent, ranging from water to organic solvents to strong acids or bases. Conditions (mobile and stationary phases, additives, pH, temperatures, etc.) can be found to separate almost all pairs of analytes. For example, LC is immensely successful in the separation of enantiomers. Good selectivities can be accompanied by high efficiencies in a very short time, using contemporary ultrahigh-performance liquid chromatography (UHPLC) instrumentation and (short) columns packed with sub-2-μm particles. However, LC cannot deliver very high efficiencies in a short time. Unlike other techniques, such as gas chromatography (GC) or capillary electrophoresis (CE), plate counts exceeding 100?000 are not routinely obtained in LC. As a result, LC cannot easily deal with complex mixtures that contain more than a few dozen analytes. While the selectivity between any pair of analytes can be maximized, these peaks may then start to overlap with other relevant analytes or with matrix compounds. There simply is not enough room in LC chromatograms to separate very many compounds that behave “statistically”, and the attainable peak capacity does not suffice to separate complex samples. As a rule of thumb, LC offers a high probability of success for separating samples containing 10 or 20 components in 1 or 2 h or up to 50 components in about 10 h.When dealing with complex samples, comprehensive two-dimensional liquid chromatography (LC × LC) is an attractive approach . Peak capacities of several thousands can be achieved, and 10?000 is within reasonable reach. For high-resolution separations, LC × LC is also much faster, with a peak-production rate (peak capacity divided by the analysis time) of about 1 peak per second, as compared to 1 peak per minute for typical high-resolution one-dimensional LC (1D-LC). The “room” in the chromatogram created by the much-enhanced peak capacity creates the possibility to fully employ two different selectivities. Groups (or “classes”) of analytes can be very efficiently separated from each other, provided that the selectivities (retention mechanisms) employed in the two dimensions are very different. In the most favorable case, in which the retention times in the two dimensions are completely independent, we speak of orthogonal separations. When separation is obtained using two very different retention mechanisms, the uncertainty of peak assignment can be dramatically reduced. Because of the diverse selectivities, high degrees of orthogonality can be achieved in combination with mass spectrometry (LC × LC-MS). In comparison, the combination of ion-mobility spectrometry (IMS) and MS is very fast but very much less orthogonal.Pittet, B., Lefebvre, B., Saleh, F., Perrillat, J.-P., 2018. Orbital control on exceptional fossil preservation. Geology 47, 103-106. fossil preservation is defined by the preservation of soft to lightly sclerotized organic tissues. The two most abundant types of soft-tissue preservation are carbonaceous compressions and replicates in authigenic minerals. In the geological record, exceptionally preserved soft fossils are rare and generally limited to only a few stratigraphic intervals. In the Fezouata Shale (Lower Ordovician, southern Morocco), we found that deposits yielding pyritized soft tissues contain iron-rich silicate minerals. These minerals played a crucial role in inhibiting the decay of dead individuals and are comparable to those found in formations yielding carbonaceous soft parts around the world. Furthermore, we found that iron-rich minerals show a cyclic pattern of occurrence (of ～100 k.y. periodicity) implicating a short-period eccentricity control on iron availability through the general oceanic and atmospheric circulations. Our results identify, for the first time, an external climate forcing on exceptional preservation and show that orbital forcing may be a level-selective parameter responsible for the discontinuous occurrence of horizons preserving soft parts around the world.Podgornik, A., 2019. Pressure drop in liquid chromatography. Journal of Separation Science 42, 72-88. Measurement of pressure drop is routinely performed during chromatographic runs. In many cases this information is only used for regulation of mobile phase flow rate to keep pressure drop below defined limit. However, pressure drop can provide additional important information about performance of chromatographic process. In this review different parameters affecting pressure drop such as compressibility of chromatographic media, nature of applied sample and mobile phase flow regime are discussed. Detailed analysis correlating organization of particle based chromatographic media and pressure drop is presented together with its extension to convective media such as membranes and monoliths but also novel 3D printed media. Finally, estimation of layer thickness formed by adsorbed molecules based on a pressure drop data is presented and its applicability is discussed.Podolskaya, E.P., Gladchuk, A.S., Keltsieva, O.A., Dubakova, P.S., Silyavka, E.S., Lukasheva, E., Zhukov, V., Lapina, N., Makhmadalieva, M.R., Gzgzyan, A.M., Sukhodolov, N.G., Krasnov, K.A., Selyutin, A.A., Frolov, A., 2019. Thin film chemical deposition techniques as a tool for fingerprinting of free fatty acids by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Analytical Chemistry 91, 1636-1643. fingerprinting is a powerful analytical technique, giving access to high-throughput identification and relative quantification of multiple metabolites. Because of short analysis times, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) is the preferred instrumental platform for fingerprinting, although its power in analysis of free fatty acids (FFAs) is limited. However, these metabolites are the biomarkers of human pathologies and indicators of food quality. Hence, a high-throughput method for their fingerprinting is required. Therefore, here we propose a MALDI-TOF-MS method for identification and relative quantification of FFAs in biological samples of different origins. Our approach relies on formation of monomolecular Langmuir films (LFs) at the interphase of aqueous barium acetate solution, supplemented with low amounts of 2,5-dihydroxybenzoic acid, and hexane extracts of biological samples. This resulted in detection limits of 10–13–10–14 mol and overall method linear dynamic range of at least 4 orders of magnitude with accuracy and precision within 2 and 17%, respectively. The method precision was verified with eight sample series of different taxonomies, which indicates a universal applicability of our approach. Thereby, 31 and 22 FFA signals were annotated by exact mass and identified by tandem MS, respectively. Among 20 FFAs identified in Fucus algae, 14 could be confirmed by gas chromatography-mass spectrometry.Polasko, A.L., Zulli, A., Gedalanga, P.B., Pornwongthong, P., Mahendra, S., 2019. A mixed microbial community for the biodegradation of chlorinated ethenes and 1,4-dioxane. Environmental Science & Technology Letters 6, 49-54. developed a microbial community capable of biodegrading mixtures of chlorinated ethenes and 1,4-dioxane under varying redox conditions. Achieving the removal of chlorinated ethenes as well as 1,4-dioxane to below health advisory levels in groundwater that has anaerobic and aerobic zones has proven to be challenging. However, our mixed community, composed of the anaerobic chlorinated ethene-degrading consortium KB-1 and aerobic bacterial strain, Pseudonocardia dioxanivorans CB1190, was able to reduce trichloroethene (TCE) in anaerobic environments and oxidize 1,4-dioxane in the presence of oxygen. Aerobic biodegradation of cis-1,2-dichloroethene by CB1190 was also confirmed, thus decreasing the accumulation of TCE transformation products, such as vinyl chloride. The results of this study demonstrate that the assembled microbial community not only survived significant redox changes but sequentially biodegraded chlorinated ethenes and 1,4-dioxane. This approach toward degrading mixed contaminants with a consortium containing anaerobic and aerobic bacteria provides greater insight as to when and how to transition from active enhanced reductive dechlorination to enhanced aerobic attenuation of chlorinated ethenes and 1,4-dioxane.Polik, C.A., Elling, F.J., Pearson, A., 2018. Impacts of paleoecology on the TEX86 sea surface temperature proxy in the Pliocene-Pleistocene Mediterranean Sea. Paleoceanography and Paleoclimatology 33, 1472-1489. TEX86 proxy, based on the distribution of isoprenoid glycerol dialkyl glycerol tetraethers (iGDGTs) from planktonic Thaumarchaeota, is widely used to reconstruct sea surface temperature (SST). Recent observations of species-specific and regionally dependent TEX86-SST relationships in cultures and the modern ocean raise the question of whether nonthermal factors may have impacted TEX86 paleorecords. Here we evaluate the effects of ecological changes on TEX86 using one Pliocene and two Pleistocene sapropels from the Mediterranean Sea. We find that TEX86-derived SSTs deviate from -derived SSTs before, during, and after each sapropel event. -derived SSTs vary by less than 6?°C, while TEX86-derived SSTs vary by up to 15?°C within a single record. Compound-specific carbon isotope compositions indicate minimal confounding influence on TEX86 from exogenous sources. Some of the variation can be accounted for by changes in nitrogen cycling intensity affecting thaumarchaeal iGDGT biosynthesis, as demonstrated by an inverse relationship between TEX86 and δ15NTN. TEX86-derived SSTs also consistently show warm anomalies in the Pleistocene, while the Pliocene samples exhibit both warmer and cooler relative offsets. These anomalies result from systematic differences between Plio-Pleistocene iGDGT distributions and both modern Mediterranean and modern, globally distributed core top samples. Through characteristic GDGT distributions, we suggest the existence of three distinct endemic populations of Thaumarchaeota in the Pliocene, Pleistocene, and modern Mediterranean Sea, respectively. Importantly, these communities prevailed during both sapropel and oligotrophic conditions. Our results demonstrate that ecological and community-specific effects must be considered when applying the TEX86 proxy to paleorecords.Pollier, J., Vancaester, E., Kuzhiumparambil, U., Vickers, C.E., Vandepoele, K., Goossens, A., Fabris, M., 2019. A widespread alternative squalene epoxidase participates in eukaryote steroid biosynthesis. Nature Microbiology 4, 226-233. are essential triterpenoid molecules that are present in all eukaryotes and modulate the fluidity and flexibility of cell membranes. Steroids also serve as signalling molecules that are crucial for growth, development and differentiation of multicellular organisms. The steroid biosynthetic pathway is highly conserved and is key in eukaryote evolution. The flavoprotein squalene epoxidase (SQE) catalyses the first oxygenation reaction in this pathway and is rate limiting. However, despite its conservation in animals, plants and fungi, several phylogenetically widely distributed eukaryote genomes lack an SQE-encoding gene. Here, we discovered and characterized an alternative SQE (AltSQE) belonging to the fatty acid hydroxylase superfamily. AltSQE was identified through screening of a gene library of the diatom Phaeodactylum tricornutum in a SQE-deficient yeast. In accordance with its divergent protein structure and need for cofactors, we found that AltSQE is insensitive to the conventional SQE inhibitor terbinafine. AltSQE is present in many eukaryotic lineages but is mutually exclusive with SQE and shows a patchy distribution within monophyletic clades. Our discovery provides an alternative element for the conserved steroid biosynthesis pathway, raises questions about eukaryote metabolic evolution and opens routes to develop selective SQE inhibitors to control hazardous organisms.Popa, M.E., Paul, D., Janssen, C., R?ckmann, T., 2019. H2 clumped isotope measurements at natural isotopic abundances. Rapid Communications in Mass Spectrometry 33, 239-251.: Molecular hydrogen (H2) is an important gas for atmospheric chemistry, and an indirect greenhouse gas due to its reaction with OH. The isotopic composition of H2 (δD) has been used to investigate its atmospheric budget; here we add a new observable, the clumped isotopic signature ΔDD, to the tools that can be used to study the global cycle of H2. Methods: A method for determining ΔDD in H2 was developed using the high‐resolution MAT 253‐Ultra isotope ratio mass spectrometer (Thermo Fisher). The HH, HD and DD abundances are quantified at medium resolution (M/ΔM?≈?6000), which is sufficient for HD+ and DD+ to be distinguished from H3+ and H2D+, respectively. The method involves sequential measurement of isotopologues, and DD is measured using an ion counter. For verification, catalytic ΔDD equilibration experiments were performed at temperatures of up to 850°C. Results: The typical precision obtained for ΔDD is 2–6‰, close to the theoretical counting statistics limit, and adequate for detecting the expected natural variations. Compatibility and medium‐term reproducibility are consistent with the precision values. The method was validated using temperature equilibration experiments, which showed a dependence of ΔDD on temperature as expected form theoretical calculations.Conclusions: We have established a method for determining ΔDD in H2 at natural isotopic abundances, with a precision that is adequate for observing the expected variations in atmospheric and other natural H2. This method opens the road to new research on the natural H2 cycle. Pradhan, A., Ovalles, C., Moir, M., 2018. Characterization of heavy petroleum fractions by NMR techniques, in: Ovalles, C., Moir, M.E. (Eds.), The Boduszynski Continuum: Contributions to the Understanding of the Molecular Composition of Petroleum. American Chemical Society, pp. 73-86. spectroscopy continues to be a useful tool to characterize heavy petroleum fractions. Over the last few years, advancements in three techniques have opened new avenues to characterize heavy petroleum fractions and catalysts and dramatically improve our understanding of these important feedstocks: 1) incorporation of clay-gel adsorption chromatography for the separation of a heavy petroleum fraction into paraffin, aromatic, and polar fractions has enabled the extension of the Brown-Ladner method to narrower fractions; 2) Diffusion Ordered Spectroscopy (DOSY) continues to be an attractive tool to characterize heavy petroleum fractions and asphaltenes due to dependence on molecular properties such as size, shape, mass, and charge which are not included in conventional spin interactions; 3) availability of advanced instrumentation has enabled extending the application of Dynamic Nuclear Polarization (DNP) towards higher magnetic fields and has opened up new frontiers to characterize heterogeneous catalysts and heavy petroleum fractions.Prentice, B.M., McMillen, J.C., Caprioli, R.M., 2019. Multiple TOF/TOF events in a single laser shot for multiplexed lipid identifications in MALDI imaging mass spectrometry. International Journal of Mass Spectrometry 437, 30-37. mass spectrometry (MS/MS) is often used to identify lipids in matrix-assisted laser desorption/ionization imaging mass spectrometry (MALDI IMS) workflows. The molecular specificity afforded by MS/MS is crucial on MALDI time-of-flight (TOF) platforms that generally lack high resolution accurate mass measurement capabilities. Unfortunately, imaging MS/MS workflows generally only monitor a single precursor ion over the imaged area, limiting the throughput of this methodology. Herein, we demonstrate that multiple TOF/TOF events performed in each laser shot can be used to improve the throughput of imaging MS/MS. This is shown to enable the simultaneous identification of multiple phosphatidylcholine lipids in rat brain tissue. Uniquely, the separation in time achieved for the precursor ions in the TOF-1 region of the instrument is maintained for the fragment ions as they are analyzed in TOF-2, allowing for the differentiation of fragment ions of the exact same m/z derived from different precursor ions (e.g., the m/z 163 fragment ion from precursor ion m/z 772.5 is easily distinguished from the m/z 163 fragment ion from precursor ion m/z 826.5). This multiplexed imaging MS/MS approach allows for the acquisition of complete fragment ion spectra for multiple precursor ions per laser shot.Proki?, M.D., Radovanovi?, T.B., Gavri?, J.P., Faggio, C., 2019. Ecotoxicological effects of microplastics: Examination of biomarkers, current state and future perspectives. TrAC Trends in Analytical Chemistry 111, 37-46. about interactions between microplastics and organisms is on the rise. Accessing organisms' responses to these chemically “inert” compounds plays an important role in determining their potential toxicity. Microplastics from the environment tend to accumulate and move through living organisms, inducing a variety of biological effects, such as disturbances in energy metabolism, oxidative balance, antioxidative capacity, DNA, immunological, neurological and histological damage. In the present review, we summarized the adverse effects of different size, concentrations and types of microplastics on animals' antioxidative system, energy metabolism and nervous system. Results showed that microplastics can: induce oxidative damage (increased lipid peroxidation and DNA strand breaks); alter antioxidative system (superoxide dismutase, catalase and glutathione peroxidase were parameters with the highest and significant changes in activities) and metabolism (isocitrate dehydrogenase and lactate dehydrogenase activity); and have neurotoxic effects (inhibition of acetylcholinesterase activity). The effects were depending on size and dose of used microplastics, and/or their interaction with other xenobiotics. We examined also potential strategies and offer research priorities for current and future studies.Qian, K., Yang, S., Dou, H.-e., Pang, J., Huang, Y., 2019. Formation damage due to asphaltene precipitation during CO2 flooding processes with NMR technique. Oil & Gas Science and Technology – Revue d’IFP Energies nouvelles 74, Article 11. order to quantitatively evaluate the pore-scale formation damage of tight sandstones caused by asphaltene precipitation during CO2 flooding, the coreflood tests and Nuclear Magnetic Resonance (NMR) relaxometry measurements have been designed and applied. Five CO2 coreflood tests at immiscible, near-miscible and miscible conditions were conducted and the characteristics of the produced oil and gas were analyzed. For each coreflood test, the T2 spectrum of the core sample was measured and compared before and after CO2 flooding to determine the asphaltene precipitation distribution in pores. It is found that, the solubility and extraction effect of the CO2 plays a more dominant role in the CO2-EOR (Enhanced Oil Recovery) process with higher injection pressure. And, more light components are extracted and recovered by the CO2 and more heavy components including asphaltene are left in the core sample. Thus, the severity of formation damage influenced by asphaltene precipitation increases as the injection pressure increases. In comparison to micro and small pores (0.1–10 ms), the asphaltene precipitation has a greater influence on the medium and large pores (10–1000 ms) due to the sufficient interaction between the CO2 and crude oil in the medium and large pores. Furthermore, the asphaltene precipitation not only causes pore clogging, but also induces rock wettability to alter towards oil-wet direction.Qu, H., Li, P., Luo, T., Guan, L., Fan, Y., Wang, L., 2018. Carbon isotopic evolution characteristics and the geological significance of the Permian carbonate stratotype section in the northern Upper-Yangtze region, southern China. Acta Geologica Sinica - English Edition 92, 2367-2381. Permian global mass extinction events and the eruption of the Emeishan flood basalts in the Upper Yangtze region should display certain responses during the evolution of carbon isotope. In this paper, the Permian carbon isotopic evolution in the Upper Yangtze region is examined through systematic stratotype section sampling and determination of 13C in the northern Upper‐Yangtze regions and Southern China. Additionally, the carbon isotopic evolution response characteristics of the geological events in the region are evaluated, comparing the sea‐level changes in the Upper Yangtze region and the global sea‐level change curves. Results of this study indicated that the carbon isotopic curves of the Permian in the Upper Yangtze region are characterized by higher background carbon‐isotope baseline values, with three distinct negative excursions, which are located at the Middle–Late Permian boundary and the late period and end of the Late Permian. The three distinct negative excursions provide an insightful record of the global Permian mass extinction events and the eruption of the Emeishan flood basalts in the Upper Yangtze region. The first negative excursion at the Middle–Late Permian boundary reflected the eruption of the Emeishan flood basalts, a decrease in sea level, and biological extinction events of different genera in varying degrees. The second negative excursion in the Late Permian included a decrease in sea level and large‐scale biological replacement events. The third negative excursion of the carbon isotope at the end of the Permian corresponded unusually to a rise rather than a decrease in sea level, and it revealed the largest biological mass extinction event in history.Raczka, B., Dietze, M.C., Serbin, S.P., Davis, K.J., 2018. What limits predictive certainty of long-term carbon uptake? Journal of Geophysical Research: Biogeosciences 123, 3570-3588. biosphere models can help identify physical processes that control carbon dynamics, including land-atmosphere CO2 fluxes, and have the potential to project the terrestrial ecosystem response to changing climate. It is important to identify ecosystem processes most responsible for model predictive uncertainty and design improved model representation and observational system studies to reduce that uncertainty. Here we identified model parameters that contribute the most uncertainty to long-term (~100?years) projections of net ecosystem exchange, net primary production, and aboveground biomass within a mechanistic terrestrial biosphere model (Ecosystem Demography, version 2.1) ED2. An uncertainty analysis identified parameters that represent the quantum efficiency of light to photosynthetic conversion, leaf respiration and soil-plant water transfer as the highest contributors to model uncertainty regardless of time frame (annual, decadal, and centennial) and output (e.g., net ecosystem exchange, net primary production, aboveground biomass). Contrary to expectations, the contribution of successional processes related to reproduction, competition, and mortality did not increase as the time scale increased. These findings suggest that uncertainty in the parameters governing short-term ecosystem processes remains the most significant bottleneck to reducing predictive uncertainty. Key actions to reduce parameter uncertainty include more leaf-level trait measurements across multiple sites for quantum efficiency and leaf respiration rate. Further, the empirical representation of soil-plant water transfer should be replaced with a mechanistic, hydraulic representation of water flow, which can be constrained with direct measurements. This analysis focused on aboveground ecosystem processes. The impact of belowground carbon cycling, initial conditions, and meteorological forcing should be addressed in future studies.Radnia, H., Solaimany Nazar, A.R., Rashidi, A., 2019. Effect of asphaltene on the emulsions stabilized by graphene oxide: A potential application of graphene oxide in enhanced oil recovery. Journal of Petroleum Science and Engineering 175, 868-880. this research, graphene oxide (GO) is used to prepare stable Pickering emulsions in chemical flooding for enhanced oil recovery (EOR). The effects of GO concentration (0–7?mg/mL), salinity of aqueous phase (0–10?wt%), and asphaltene concentration in organic phase (0–2?wt%) on the stability and morphology of the emulsions are examined. Moreover, the influence of these independent variables on the interfacial tension (IFT) between organic and aqueous phase is assessed through response surface methodology. The results show that the concentrations of GO and asphaltene have the most significant effect on the IFT; indeed, the IFT reduces with increasing both GO and asphaltene concentrations. Defining two quantitative indexes make it possible to compare the efficiency of emulsions formation (ESVI) and the stability of formed emulsions during time (ESTI) against creaming at different conditions. The maximum reported values for the ESTI and ESVI are 100% and 70%, respectively. In all conditions, the type of emulsions is oil-in-water (O/W) which is more suitable in EOR. However, water-in-oil emulsions (W/O) are observed at asphaltene concentrations higher than 1.5?wt%. For dominating this phenomenon, the water/oil ratio should be increased. At the presence of asphaltene and salinities higher than 1?wt%, some water-in-oil-in-water (W/O/W) multiple emulsion droplets are observed. The minimum of the reported average droplet size is 0.69?μm for GO concentration of 1?mg/mL and asphaltene concentration of 0.05?wt%. These results demonstrate the potential applications of graphene based functional materials for EOR.Raghavan, V., Johnson, J.L., Stec, D.F., Song, B., Zajac, G., Baranska, M., Harris, C.M., Schley, N.D., Polavarapu, P.L., Harris, T.M., 2018. Absolute configurations of naturally occurring [5]- and [3]-ladderanoic acids: Isolation, chiroptical spectroscopy, and crystallography. Journal of Natural Products 81, 2654-2666. have isolated mixtures of [5]- and [3]-ladderanoic acids 1a and 2a from the biomass of an anammox bioreactor and have separated the acids and their phenacyl esters for the first time by HPLC. The absolute configurations of the naturally occurring acids and their phenacyl esters are assigned as R at the site of side-chain attachment by comparison of experimental specific rotations with corresponding values predicted using quantum chemical (QC) methods. The absolute configurations for 1a and 2a were independently verified by comparison of experimental Raman optical activity spectra with corresponding spectra predicted using QC methods. The configurational assignments of 1a and 2a and of the phenacyl ester of 1a were also confirmed by X-ray crystallography.Rahimi, P., 2018. Effect of bitumen molecular transformation during upgrading on asphaltenes chemistry and compatibility, in: Ovalles, C., Moir, M.E. (Eds.), The Boduszynski Continuum: Contributions to the Understanding of the Molecular Composition of Petroleum. American Chemical Society, pp. 189-201. chemistry of thermal conversion of bitumen and heavy oil is complex not only because bitumen consists of a variety of different molecular structures, but also the thermal chemistry is not selective and many reaction pathways lead to the production of a complex mixture of products. It has been recognized through the genius of Mieczyslaw (Mietek) Boduszynski’s continuum petroleum model that one can relate the molecular structure of these complex hydrocarbons to their boiling points. Further, with the recent advancement in analytical instrumentation such as FT-ICR mass spectrometry the chemical structure of these complex hydrocarbons can be identified and structural reactivity and phenomenon of molecular interactions such as asphaltenes aggregation can be illustrated with confidence. It is important to realize that any changes in the molecular structure of bitumen at the primary stage of conversion to produce synthetic crude, would have a significant impact on downstream processing and handling. In this chapter methods developed for measuring asphaltenes stability and solubility parameters will be reviewed. Factors influencing fouling tendency of crudes because of blending or processing as well as correlations between chemical composition and crude fouling propensity will be discussed.Rani, S., Padmanabhan, E., Prusty, B.K., 2019. Review of gas adsorption in shales for enhanced methane recovery and CO2 storage. Journal of Petroleum Science and Engineering 175, 634-643. concept of increased methane recovery with simultaneous CO2 sequestration in unconventional reservoirs like gas shales has been studied extensively. A clear understanding of storage mechanism and geo-chemical characteristics of shale gas reservoirs is necessary for predicting the gas reserve and evaluating reservoir potential. The present article reviews literature on adsorption of methane and carbon dioxide on shale for the purpose of methane recovery with simultaneous CO2 sequestration in shale gas reservoirs. The objective of this article is to discuss the technical aspects related to gas adsorption and characterization (both composition and pore) concerning shale gas reservoirs. The various adsorption mechanisms, different adsorption isotherm types and shales as a microporous adsorbent are discussed. Using the published information in literature, methane and carbon dioxide adsorption in shales and its relationship with different geochemical parameters like organic matter content, mineralogy, pore-structure and moisture as essential controls for gas adsorption in shale are discussed. Studies that answer the concerns on effect of shale composition and pore characteristics on adsorption capacity of heterogeneous shale are also summarised.Rascovan, N., Sj?gren, K.-G., Kristiansen, K., Nielsen, R., Willerslev, E., Desnues, C., Rasmussen, S., 2019. Emergence and spread of basal lineages of Yersinia pestis during the Neolithic decline. Cell 176, 295-305.e10. 5,000 and 6,000 years ago, many Neolithic societies declined throughout western Eurasia due to a combination of factors that are still largely debated. Here, we report the discovery and genome reconstruction of Yersinia pestis, the etiological agent of plague, in Neolithic farmers in Sweden, pre-dating and basal to all modern and ancient known strains of this pathogen. We investigated the history of this strain by combining phylogenetic and molecular clock analyses of the bacterial genome, detailed archaeological information, and genomic analyses from infected individuals and hundreds of ancient human samples across Eurasia. These analyses revealed that multiple and independent lineages of Y. pestis branched and expanded across Eurasia during the Neolithic decline, spreading most likely through early trade networks rather than massive human migrations. Our results are consistent with the existence of a prehistoric plague pandemic that likely contributed to the decay of Neolithic populations in Europe.Rashid, Z., Wilfred, C.D., Gnanasundaram, N., Arunagiri, A., Murugesan, T., 2019. A comprehensive review on the recent advances on the petroleum asphaltene aggregation. Journal of Petroleum Science and Engineering 176, 249-268. finds a distinguished position in current research on liquid and solid hydrocarbon fuels due to its self-aggregating nature. The presence of asphaltene in crude oil will reduce the quality of crude oil itself by increasing the operating cost due to the arterial blockage in extraction, transportation and refining process. To date, the self-association of asphaltene has been widely explored around the world, even at the molecular level. Quite a few studies have led to the development of model compounds that resemble their chemical and colloidal characteristics. Based on the veracity regarding asphaltene structural configuration, it is believed that the mechanism of asphaltene self-aggregation needs special attention to process asphaltenic crude oil. The intention of this review is to understand the mechanism of petroleum asphaltene aggregation with the help of the studied model compounds and discuss the recent developments with respect to its colloidal and interfacial activity. The complexities of asphaltene science have been addressed comprehensively and controversies regarding asphaltene aggregation has been successfully resolved. This review provides insight to readers regarding the asphaltene colloidal and aggregated structure. At last, a point of view toward future advancement is also proposed with the objective of conquering challenges and fortifying further research into this promising field.Reber, E.A., Kerr, M.T., Whelton, H.L., Evershed, R.P., 2019. Lipid residues from low-fired pottery. Archaeometry 61, 131-144. paper assesses the fate of lipids associated with low‐temperature and pit‐fired pottery to determine to what degree organic compounds persist or are removed during short‐firing episodes below 800?°C. Three different types of clay were fired using contrasting techniques including at 400?°C for 4?h in a muffle furnace, and pit‐firing in which pottery was fired to higher temperatures but for shorter periods of time. Total lipid extracts obtained by solvent extraction of test sherds were screened using gas chromatography‐flame ionization detection (GC‐FID) to determine the lipid concentrations and gas chromatography–mass spectrometry (GC–MS) to identify the organic compounds present. The results showed that firing of clay removes all naturally occurring alkyl lipids; however, during pit‐firing, diterpenoid lipids were introduced into the clay as a condensate from pine (?Pinus spp.) wood used as fuel. These results confirm that alkyl lipids, e.g., fatty acids, can be reliably associated with the use of vessels, although caution is required when interpreting the origins of lipids that might derive from fuel used in firing.Rechsteiner, C.E., 2018. Attainable product yield distribution curve: A roadmap to crude oil composition, in: Ovalles, C., Moir, M.E. (Eds.), The Boduszynski Continuum: Contributions to the Understanding of the Molecular Composition of Petroleum. American Chemical Society, pp. 205-221. oil is an exceedingly complex mixture of organic compounds. Advances in separations and measurement technologies, especially the utilization of Gas Chromatography (GC), allow robust measurement of the distribution of material within a crude oil from C3 up to ca. C110 to C120 calibrated against normal paraffin standards. The focus of this chapter is on the application of Detailed Hydrocarbon Analysis (DHA) for light ends and GC Simulated Distillation (SimDis) for distillable fractions and residuum. The chapter discusses the concepts behind these technologies, the robustness of these measurements, and the importance of the composite yield distribution curve obtained from combining these measurements.Reinhardt, M., Goetz, W., Duda, J.P., Heim, C., Reitner, J., Thiel, V., 2019. Organic signatures in Pleistocene cherts from Lake Magadi (Kenya), analogs for early Earth hydrothermal deposits. Biogeosciences Discussions 2019, 1-40. matter in Archean hydrothermal cherts may provide an important archive for molecular traces of earliest life on Earth. The geobiological interpretation of this archive, however, requires a sound understanding of organic matter preservation and alteration in hydrothermal systems. Here we report on organic matter (including molecular biosignatures) enclosed in hydrothermally influenced cherts of the Pleistocene Lake Magadi (Kenya; High Magadi Beds and Green Beds) – important analogs for Archean cherts. The Magadi cherts contain low organic carbon (<0.4wt.%) that occurs in form of finely dispersed clots, layers, or encapsulated within microscopic carbonate rhombs. Both, extractable (bitumen) and non-extractable organic matter (kerogen) was analyzed. The bitumens contain immature biolipids like glycerol mono- and diethers (e.g., archaeol and extended archaeol), fatty acids and – alcohols indicative for, inter alia, thermophilic cyanobacteria, sulfate reducers, and haloarchaea. However, co-occurring geolipids such as n-alkanes, hopanes, and polycyclic aromatic hydrocarbons (PAHs) indicate that a fraction of the bitumen has been thermally altered to early or peak oil window maturity. This more mature fraction likely originated from defunctionalization of dissolved organic matter and/or hydrothermal petroleum formation at places of higher thermal flux. Like the bitumens, the kerogens also show variations in thermal maturities, which can partly be explained by admixture of thermally pre-altered macromolecules. However, findings of archaea-derived isoprenoid moieties in some of the kerogens indicate that a fast sequestration of microbial lipids into kerogen must have occurred while hydrothermal alteration was active. We posit that such early sequestration may enhance the survival of molecular biosignatures during in-situ hydrothermal (and post-depositional) alteration through deep time. Furthermore, the co-occurrence of organic matter with different thermal maturities in the Lake Magadi cherts suggests that similar findings in Archean hydrothermal deposits could partly reflect original environmental conditions, and not exclusively post-depositional overprint or contamination. Our results support the view that kerogen in Archean hydrothermal cherts may contain important information on early life. Our study also highlights the suitability of Lake Magadi as an analog system for hydrothermal chert environments on the Archean Earth.Renders, T., Van den Bossche, G., Vangeel, T., Van Aelst, K., Sels, B., 2019. Reductive catalytic fractionation: state of the art of the lignin-first biorefinery. Current Opinion in Biotechnology 56, 193-201. catalytic fractionation (RCF) of lignocellulose is an emerging biorefinery scheme that combines biomass fractionation with lignin depolymerisation. Central to this scheme is the integration of heterogeneous catalysis, which overcomes the tendency of lignin to repolymerise. Ultimately, this leads to a low-Mw lignin oil comprising a handful of lignin-derived monophenolics in close-to-theoretical yield, as well as a carbohydrate pulp. Both product streams are considered to be valuable resources for the bio-based chemical industry. This Opinion article sheds light on recently achieved milestones and consequent research opportunities. More specifically, mechanistic studies have established a general understanding of the elementary RCF steps, which include (i) lignin extraction, (ii) solvolytic and catalytic depolymerisation and (iii) stabilisation. This insight forms the foundation for recently developed flow-through RCF. Compared to traditional batch, flow-through RCF has the advantage of (i) separating the solvolytic steps from the catalytic steps and (ii) being a semi-continuous process; both of which are beneficial for research purposes and for industrial operation. Although RCF has originally been developed for ‘virgin’ biomass, researchers have just begun to explore alternative feedstocks. Low-value biomass sources such as agricultural residues, waste wood and bark, are cheap and abundant but are also often more complex. On the other side of the feedstock spectrum are high-value bio-engineered crops, specifically tailored for biorefinery purposes. Advantageous for RCF are feedstocks designed to (i) increase the total monomer yield, (ii) extract lignin more easily, and/or (iii) yield unconventional, high-value products (e.g. alkylated catechols derived from C-lignin). Taking a look at the bigger picture, this Opinion article highlights the multidisciplinary nature of RCF. Collaborative efforts involving chemists, reactor engineers, bioengineers and biologists working closer together are, therefore, strongly encouraged.Ribeiro, F., O'Brien, J.W., Galloway, T., Thomas, K.V., 2019. Accumulation and fate of nano- and micro-plastics and associated contaminants in organisms. TrAC Trends in Analytical Chemistry 111, 139-147. a decade of research on the environmental impacts of microplastics, a knowledge gap remains on the processes by which micro and nanoplastics pass across biological barriers, enter cells and are subject to biological mechanisms. Here we summarize available literature on the accumulation of microplastics and their associated contaminants in a variety of organisms including humans. Most data on the accumulation of microplastics in both field and lab studies are for marine invertebrates. Microplastics accumulation data for insects, birds, marine mammals and sea turtles are scarce due to methodological issues. There is no conclusive evidence for the mode of accumulation of microplastics in either mammals or humans. The mechanism of chemical partitioning, role of contaminants associated with plastics, and mode of action of both nano- and micro-plastics and associated chemicals in a range of organisms and associated compartments/tissues also requires further research.Richert-P?ggeler, K.R., Franzke, K., Hipp, K., Kleespies, R.G., 2019. Electron microscopy methods for virus diagnosis and high resolution analysis of viruses. Frontiers in Microbiology 9, 3255. doi: 10.3389/fmicb.2018.03255. term “virosphere” describes both the space where viruses are found and the space they influence, and can extend to their impact on the environment, highlighting the complexity of the interactions involved. Studying the biology of viruses and the etiology of virus disease is crucial to the prevention of viral disease, efficient and reliable virus diagnosis, and virus control. Electron microscopy (EM) is an essential tool in the detection and analysis of virus replication. New EM methods and ongoing technical improvements offer a broad spectrum of applications, allowing in-depth investigation of viral impact on not only the host but also the environment. Indeed, using the most up-to-date electron cryomicroscopy methods, such investigations are now close to atomic resolution. In combination with bioinformatics, the transition from 2D imaging to 3D remodeling allows structural and functional analyses that extend and augment our knowledge of the astonishing diversity in virus structure and lifestyle. In combination with confocal laser scanning microscopy, EM enables live imaging of cells and tissues with high-resolution analysis. Here, we describe the pivotal role played by EM in the study of viruses, from structural analysis to the biological relevance of the viral metagenome (virome).Rickard, P.C., Uher, G., Upstill-Goddard, R.C., Frka, S., Mustaffa, N.I.H., Banko-Kubis, H.M., Cvite?i? Ku?an, A., Ga?parovi?, B., Stolle, C., Wurl, O., Ribas-Ribas, M., 2019. Reconsideration of seawater surfactant activity analysis based on an inter-laboratory comparison study. Marine Chemistry 208, 103-111., or surface-active substances (SAS), are amphipathic organic substances that adsorb on aquatic phase boundaries, including the air-sea interface that covers ~70% of Earth's surface. SAS thus mediate all mass transfer across the air-sea interface and are central to planetary scale biogeochemical processes. SAS are routinely quantified in seawater and freshwater in terms of total surfactant activity (SA), using alternating current (AC) out-of-phase voltammetry with a hanging mercury drop electrode (HMDE). Although this technique is well established, method modifications have been implemented and differing calibration procedures adopted in individual research laboratories. Increasing interest in the environmental roles of SAS prompts a timely inter-comparison of these varying analytical approaches. Using sea-surface microlayer (SML: uppermost 80?μm layer sampled) and sub-surface (SSW: 1?m depth sampled) seawater from Jade Bay (south-eastern North Sea), we carried out the first inter-laboratory comparison for SA, using methods and calibration protocols previously established in three participating laboratories. The internal calibration protocol follows direct calibrations of individual samples against the model surfactant Triton-X-100 during analysis, whereas external calibration produces independent Triton-X-100 calibration curves; both protocols express SAS concentrations in Triton-X-100?equivalents (T-X-100?eq.). There was no significant difference between SA derived via internal or external calibration protocols, or by using different analytical instruments (range in Kruskall-Wallis and Dunn-Bonferroni post-hoc test p-values: 0.062–1.000), except where freeze/thaw degradation was suspected to have occurred during transit (p?<?.001). We recommend using discrete calibration standards during external calibration. Irrespective of any differences in SA determined by the three laboratories, the SA enrichment factor (EF: =SASML/SASSW) was not affected for any sample; the root mean square error (±one standard deviation) between all laboratories was 0.156?±?0. 226 (n?=?45). We present and discuss recommendations for a standard analytical protocol to ensure the inter-laboratory compatibility of SAS measurements into the future.Rivard, C., Bordeleau, G., Lavoie, D., Lefebvre, R., Ladevèze, P., Duchesne, M.J., Séjourné, S., Crow, H., Pinet, N., Brake, V., Bouchedda, A., Gloaguen, E., Ahad, J.M.E., Malet, X., Aznar, J.C., Malo, M., 2019. Assessing potential impacts of shale gas development on shallow aquifers through upward fluid migration: A multi-disciplinary approach applied to the Utica Shale in eastern Canada. Marine and Petroleum Geology 100, 466-483. impacts of shale gas development on shallow aquifers has raised concerns, especially regarding groundwater contamination. The intermediate zone separating shallow aquifers from shale gas reservoirs plays a critical role in aquifer vulnerability to fluid upflow, but the assessment of such vulnerability is challenging due to the general paucity of data in this intermediate zone. The ultimate goal of the project reported here was to develop a holistic multi-geoscience methodology to assess potential impacts of unconventional hydrocarbon development on fresh-water aquifers related to upward migration through natural pathways. The study area is located in the St. Lawrence Lowlands (southern Quebec, Canada), where limited oil and gas exploration and no shale gas production have taken place. A large set of data was collected over a ～500?km2 area near a horizontal shale gas exploration well completed and fracked into the Utica Shale at a depth of ≈2?km. To investigate the intermediate zone integrity, this project integrated research results from multiple sources in order to obtain a better understanding of the system hydrodynamics, including geology, hydrogeology, deep and shallow geophysics, soil, rock and groundwater geochemistry, and geomechanics. The combined interpretation of the multi-disciplinary dataset demonstrates that there is no evidence of, and a very limited potential for, upward fluid migration from the Utica Shale reservoir to the shallow aquifer. Microbial and thermogenic methane in groundwater of this region appear to come from the shallow, organic-rich, fractured sedimentary rocks making up the regional aquifer. Nonetheless, diluted brines present in a few shallow wells close to and downstream of a normal fault revealed that some upward groundwater migration occurs, but only over a few hundred meters from the surface based on the isotopic signature of methane. The methodology developed should help support regulations related to shale gas development aiming to protect groundwater.Rivers, M.L., Gwinnett, C., Woodall, L.C., 2019. Quantification is more than counting: Actions required to accurately quantify and report isolated marine microplastics. Marine Pollution Bulletin 139, 100-104. on marine microplastics continues to increase in popularity, with a large number of studies being published every year. However, with this plethora of research comes the need for a standardised approach to quantification and analysis procedures in order to produce comparative assessments. Using data collected from neuston nets in 2016, parameters for quantifying microplastics were compared. Surface area was the most accurate parameter to describe plastic size and should be used to describe plastic quantity (per km2 or m3), alongside abundance. Of the two most commonly used methods for calculating plastic concentration (flowmeter and ship's log), ship's log provided consistently smaller abundances, with the exception of one sample, calling for a standardisation in the techniques and measurements used to quantify floating microplastics.Rizzi, A., Roy, S., Bellenger, J.-P., Beauregard, P.B., 2019. Iron homeostasis in Bacillus subtilis requires siderophore production and biofilm formation. Applied and Environmental Microbiology 85, Article e02439-18.: Iron (Fe) is the most important metal in biology. Despite its abundance, Fe is mostly present as a ferric form in soils, strongly limiting its bioavailability. To overcome the challenge of Fe acquisition, many microorganisms produce siderophores to retrieve Fe from natural sources. Another ubiquitous feature of bacteria in natural environments is biofilm formation. Previous studies showed that external Fe strongly influenced biofilm formation in several bacteria, suggesting that this microenvironment plays a mechanistic role in micronutrient acquisition for bacteria. Here, we applied a complementary set of analytical methods and deletion mutants to evaluate the role of biofilm formation, siderophore production, and their interaction in Fe homeostasis in Bacillus subtilis. We observed that Fe homeostasis, i.e., active growth at a constant intracellular Fe concentration, requires both siderophore production and biofilm formation. Also, we report that in B. subtilis, both biofilm formation and siderophore production are required to achieve active Fe acquisition from the medium and to sustain normal growth. Furthermore, we provide evidence that the formation of biofilm slightly enhances the kinetics of Fe complexation by catechol siderophores and markedly improves siderophore use efficiency. These results provide new perspectives on the mechanism underlying siderophore-based acquisition of Fe in biofilm-forming bacteria.Importance: Iron acquisition is of fundamental importance for microorganisms, since this metal is generally poorly bioavailable under natural conditions. In the environment, most bacteria are found tightly packed within multicellular communities named biofilms. Here, using the soil Gram-positive bacterium Bacillus subtilis, we show that biofilm formation and the production of siderophores, i.e., small molecules specifically binding metals, are both essential to ensure Fe uptake from the medium and maintain cellular Fe homeostasis. The biofilm matrix appears to play an important role favoring the efficient usage of siderophores. Taken together, our results demonstrate a close link between biofilm formation and iron acquisition in B. subtilis, allowing a better comprehension of how bacteria can cope with metal limitation under environmental conditions.Robbins, L.J., Konhauser, K.O., Warchola, T.J., Homann, M., Thoby, M., Foster, I., Mloszewska, A.M., Alessi, D.S., Lalonde, S.V., 2019. A comparison of bulk versus laser ablation trace element analyses in banded iron formations: Insights into the mechanisms leading to compositional variability. Chemical Geology 506, 197-224. iron formations (BIF) represent one of the few chemical sedimentary archives available for exploring the redox state of the Precambrian atmosphere-ocean system and the marine availability of biologically critical trace nutrients through time. Temporal records compiled for a number of trace elements show a relatively wide spread in concentrations spanning several orders of magnitude within a single deposit. It has been suggested that this spread is present in both bulk rock digestion and laser ablation data, however, the comparability of data from the two methods has not been thoroughly evaluated. Here, we provide a statistical assessment of how comparable laser ablation data of individual BIF hematite and magnetite grains are to one another, as well as how closely averages of laser ablation data approximate bulk rock values. To do so, we use (laser ablation)-high resolution inductively coupled plasma mass spectrometry ((LA)-HR-ICP-MS) data from 14 BIF slabs and corresponding powders that span four different formations. We focus in particular on BIF from the ≥3.75?Ga Nuvvuagittuq Supracrustal Belt (Québec, Canada) and multiple BIF deposits of the 2.6–2.45?Ga Hamersley Group (North Western Australia), representing deposits separated by over a billion years and of differing metamorphic grade. The scaling between selected transition metals is also evaluated in light of expectations for possible delivery mechanisms of trace elements from seawater to BIF precursor sediments – the adsorption to hydrous ferric oxides, biological vectors, and detrital influence. Our findings show that average trace element concentrations between bulk versus laser ablation data typically vary within an order of magnitude. Furthermore, reproducibility between the two methods appears to be independent of formation age, metamorphic grade, or depositional setting. These findings underscore the overall fidelity of the BIF record at capturing seawater compositional signatures at various scales. We demonstrate that evaluations of ancient seawater chemistry using the BIF record are best served by a combined approach utilizing both bulk rock and laser ablation data, as bulk methods offer the most conservative proxy data for ancient seawater composition but may mask significant enrichments or depletions that are detectable at the grain-scale by laser ablation.Robinson, C., 2019. Microbial respiration, the engine of ocean deoxygenation. Frontiers in Marine Science 5, 533. doi: 10.3389/fmars.2018.00533. plankton respiration is the key determinant in the balance between the storage of organic carbon in the oceans or its conversion to carbon dioxide with accompanying consumption of dissolved oxygen. Over the past fifty years, dissolved oxygen concentrations have decreased in many parts of the world’s oceans, and this trend of ocean deoxygenation is predicted to continue. Yet despite its pivotal role in ocean deoxygenation, microbial respiration remains one of the least constrained microbial metabolic processes. Improved understanding of the magnitude and variability of respiration, including attribution to component plankton groups, and quantification of the respiratory quotient, would enable better predictions and projections of the intensity and extent of ocean deoxygenation and of the integrative impact of ocean deoxygenation, ocean acidification, warming, and changes in nutrient concentration and stoichiometry on marine carbon storage. This study will synthesize current knowledge of respiration in relation to deoxygenation, including the drivers of its variability, identify key unknowns in our ability to project future scenarios and suggest methodological approaches to move the field forward.Rodrigues, A.R., Pivel, M.A.G., Schmitt, P., de Almeida, F.K., Bonetti, C., 2018. Infaunal and epifaunal benthic foraminifera species as proxies of organic matter paleofluxes in the Pelotas Basin, south-western Atlantic Ocean. Marine Micropaleontology 144, 38-49. late Quaternary sediment core from the continental slope of the northern sector of Pelotas Basin (southern Brazilian continental margin, 2091?m water depth) was analyzed in order to evaluate the influence of the organic matter influx in the benthic foraminiferal assemblage composition on a regional scale. This study investigated the relationship between epifaunal species (Epistominella exigua and Alabaminella weddellensis) and infaunal species (Uvigerina peregrina and Angulogerina angulosa) integrated in a relative abundance based index, the “Organic Input Index” (OrgIn). The correlation of these species with abiotic data is also discussed, including mud content, total organic carbon (TOC) and carbon stable isotope (δ13C) in Uvigerina peregrina. The age model based on one radiocarbon dating of planktonic foraminifera and oxygen isotope composition of benthic foraminifera (Uvigerina) revealed the record spans the last 112,500?yr, covering the Marine Isotope Stages (MIS) 5 to 3. The dominance of infaunal species, mainly Globocassidulina subglobosa, boliviniids and buliminiids throughout the entire core is interpreted as an indicator of an increase of organic matter supply and dominance of the eutrophic conditions in this study area. The variations found in the proportion of the epifaunal and infaunal species indicate distinctive inputs of organic matter (phytodetritus input versus bacterial activity, respectively). An increasing trend in the importance of epifaunal species from the base of the core to uppermost samples (MIS 5 to MIS 3) was also observed, which is assumed to be evidence of the higher productivity of the surface water masses in this sector of the South Atlantic during the glacial periods.Rogel, E., Roye, M., Vien, J., Witt, M., 2018. Equivalent distillation: A path to a better understanding of asphaltene characteristics and behavior, in: Ovalles, C., Moir, M.E. (Eds.), The Boduszynski Continuum: Contributions to the Understanding of the Molecular Composition of Petroleum. American Chemical Society, pp. 51-72. elution fractionation was used to evaluate property patterns in asphaltenes and their relationship to their behavior. Using the data, we developed a series of correlations that link chemical composition with solubility and thermal behavior. Additionally, an effort was made to identify the essential chemical/molecular characteristics that make petroleum materials prone to asphaltene precipitation. It was found that high hydrogen deficiencies and uneven solubility fraction distributions are the main contributors to asphaltene instability.Rozhnov, S.V., 2018. Hardgrounds of the Ordovician Baltic paleobasin as a distinct type of sedimentation induced by cyanobacterial mats. Paleontological Journal 52, 1098-1113. cold-water Volkhov and warm-water Keila hardgrounds of the Ordovician Baltic Basin represent a specialized product of cyanobacterial communities of the seafloor, another member in a group containing stromatolites and microbially induced sedimentary structures. The leading role of cyanobacterial communities in the development of hardgrounds is suggested by their macrofeatures, structure, and elemental composition revealed by SEM equipped with a microprobe microanalyzer. During the formation of the hardgrounds, the cyanobacterial films were of considerable thickness (up to 4–5 mm), but lacked vertical zonation of bacterial communities, thereby being at an intermediate stage between the mature biofilms and true mats. The soft substrate underlying hardgrounds was inhabited by an abundant infauna. Thanks to bioturbation, the cyanobacterial film was in places destroyed, which prevented the development of hardgrounds. In the warm Late Ordovician basin of northern Estonia, cyanobacterial films formed hardgrounds on the surface of ripple marks. Abundant peloids and warm pore waters facilitated further cementation and hardening of the substrate underneath the hardground before the burial of the ripple marks and the hardground. Cyanobacterial films appeared simultaneously over large areas of the seafloor due to settling of planktonic bacteria. The extracellular polymeric substances (EPSs) released by these bacteria were rapidly mineralized within a maximum of one season, apparently at a depth of 15–25 m, below the fair weather wave base. The formation of hardgrounds in bioherms occurred in a shallower environment and was patchy due to the alternation of living and dead cyanobacterial mats, mineralizing mats and resulting hardgrounds. Inhabitants of biohermal hardgrounds were producers of carbonate detritus, including of micritic size, over vast areas of the seafloor surrounding the bioherm.Rubanovich, A., Chekalin, E., Chekalina, M., Bruskin, S., Tatarinova, T.V., Kasianov, A., Rühli, F., Staub, K., Bender, N., Koepke, N., Morozova, I., 2018. Changes in biological pathways during 6,000 years of civilization in Europe. Molecular Biology and Evolution 36, 127-140. beginning of civilization was a turning point in human evolution. With increasing separation from the natural environment, mankind stimulated new adaptive reactions in response to new environmental factors. In this paper, we describe direct signs of these reactions in the European population during the past 6,000?years. By comparing whole-genome data between Late Neolithic/Bronze Age individuals and modern Europeans, we revealed biological pathways that are significantly differently enriched in nonsynonymous single nucleotide polymorphisms in these two groups and which therefore could be shaped by cultural practices during the past six millennia. They include metabolic transformations, immune response, signal transduction, physical activity, sensory perception, reproduction, and cognitive functions. We demonstrated that these processes were influenced by different types of natural selection. We believe that our study opens new perspectives for more detailed investigations about when and how civilization has been modifying human genomes.Ruhland, D., Nwoko, K., Perez, M., Feldmann, J., Krupp, E.M., 2019. AF4-UV-MALS-ICP-MS/MS, spICP-MS, and STEM-EDX for the characterization of metal-containing nanoparticles in gas condensates from petroleum hydrocarbon samples. Analytical Chemistry 91, 1164-1170. coupling of flow field flow fractionation (FlFFF) with ICP-MS/MS for the fractionation and analysis of natural nanoparticles (NPs) in environmental samples is becoming more popular. However, the applicability of this technique to nonaqueous samples, such as gas condensates from petroleum hydrocarbon samples, has not been reported yet. In this study, an asymmetric flow-field flow fractionation (AF4) system coupled with UV and MALS detectors has been optimized to perform the fractionation of natural NPs present in a gas condensate sample, using THF as the carrier liquid. Prior to this, STEM images indicated the presence of both large (200 nm and more) and smaller (50 nm and less) particles, whose irregular shape is probably due to agglomeration. AF4-UV-MALS-ICP-MS/MS confirmed the presence of various NPs and colloids, some containing aromatic compounds as well as various metals, including Hg. The recovery against an injection without crossflow is around 75% for most metals. The presence of Hg-containing NPs was confirmed with offline single particle ICP-MS (spICP-MS), using THF as a solvent. These NPs were identified as HgS using STEM-EDX. These results highlight, for the first time, that particulate matter may contaminate gas condensates with a series of elements (Al, P, S, Ti, V, Mn, Fe, Co, Cu, Zn, As, Se, Cd, Hg, and Pb), which can make the upstream use problematic, especially for mercury.Ryszka, P., Zarzyka-Ryszka, M., Anielska, T., Choczyński, M., Turnau, K., 2019. Arbuscular mycorrhizal fungi from petroleum-impacted sites in the Polish Carpathians. International Biodeterioration & Biodegradation 138, 50-56. by microorganisms is regarded as an efficient strategy for treating oil spills and wastes. Although mycorrhizal fungi do not degrade petroleum, they are a very good example of beneficial soil microorganisms that improve both the growth and vitality of plants and may enhance their bioremediation activity. In this work, arbuscular mycorrhizal fungi (AMF) were investigated in sites containing soil exposed to the long-term presence of petroleum. These sites are located in southern Poland (Carpathians), where remnants of commercial oil exploitation in the 19th century and natural petroleum seeps can be found. The mean concentrations of mineral oil and polycyclic aromatic hydrocarbons (PAH16) in the soil were 46473?μg?×?g?1 d.w. and 138?μg?×?g?1 d.w., respectively. Roots of collected petroleum-tolerant plants were analyzed using light microscopy and the associated AMF were identified by sequencing the 18S rRNA SSU genes. Most of these plants showed the presence of mycorrhizal colonization. 11 AMF phylotypes were identified: Acaulospora sp., Archaeospora sp., Claroideoglomus sp., Diversispora sp., Rhizophagus intraradices, R. iranicus; plus five groups that could not be unambiguously identified. The results of this study provide additional insight into the diversity of beneficial fungi that interact with plants which survive in a hostile environment. The data obtained are the first steps towards the application of well-adapted AMF to the bioremediation of hydrocarbon-polluted soils.Saberi, M.H., 2019. The feasibility of depositing the reservoir into hydrogen-sulfide as a result of EOR process in Cheshm-e Khosh oil field, western Iran. Arabian Journal of Geosciences 12, 66. paper focuses on analyzing different mechanisms of hydrogen-sulfide contamination in the Cheshm-e Khosh oil field, located at western Iran. The Asmari Formation is reservoir layer of the field and consists of carbonate-evaporative facies at upper parts and carbonate-clastic facies in the lower part. This study reveals that there is no possibility for thermochemical sulfate reduction, thermal cracking of sulfur-containing organic components, or reduction of metal sulfides such as pyrite and bacterial sulfate reduction, under present circumstances. Assumption of hydrogen-sulfide migration from the lower layers is invalid because, due to the presence of clastic facies in the lower part of the Asmari and remarkable existence of metal-containing minerals, the hydrogen-sulfide reacts with ferric ions and settles in form of pyrite. In addition to covering possibility of hydrogen-sulfide generation mechanisms, possibility of any growth in amount of sulfate-reduction bacteria as a result of water injection (EOR process) was also studied. Results revealed that these bacteria do not exist in the reservoir at the present time and should be avoided in the future by water injection project and drilling activities.Saeedi Dehaghani, A.H., Keshavarz, B., Mousavi Dehghani, S.A., 2019. Investigation the impact of additives on the displacement of the onset point of asphaltene precipitation using interfacial tension measurement. Energy Sources, Part A: Recovery, Utilization, and Environmental Effects 41, 1360-1371. purpose of this study is to explore the impact of additives on the displacement of the onset point of asphaltene precipitation in crude oil using the interfacial tension measurement method, based on the examined oil has been taken from Iran reservoirs. The experimental results suggest that the addition of surfactants of dodecyl benzene sulfonic acid (DBSA) and coconut diethanolamide (CDEA) to the oil has triggered the onset of asphaltene precipitation. These findings imply that CDEA has a more effective role in preventing asphaltene precipitation. Also, it was observed that increasing the concentration of the surfactants has led to obtaining greater results. Finally, critical micelle concentration was calculated to be 5000 and 4700?ppm in the cases of CDEA and DBSA, respectively.Safonov, O.G., Reutsky, V.N., Shcherbakov, V.D., Golunova, M.A., Varlamov, D.A., Yapaskurt, V.O., van Reenen, D.D., 2018. Carbon isotope characteristics as evidence of an external source of high-temperature granitoids in granulite complexes. Doklady Earth Sciences 483, 1515-1518. on the carbon isotope composition of graphite and CO2 from inclusions in quartz of granitoids of the Southern Marginal Zone (SMZ) of the Limpopo granulite belt, South Africa, are presented. The average values of δ13C for graphite and СО2 from fluid inclusions in quartz are found within the range that is typical of deep (mantle) carbon sources. The data are evidence of an external source of granitoid magmas. They are likely to be hybrid rocks that appeared during assimilation of host metapelites by trondhjemite magmas, while graphite in trondhjemites and granodiorites is a product of high-temperature (~900–1000°С) evolution of the CO2-rich fluid phase of granitoid magmas when they intrude the rocks of the granulite complex and was formed during assimilation that led to reduction of CO2 when sulfide-bearing metapelite material was contaminated by the magma.Saitta, E.T., Kaye, T.G., Vinther, J., 2019. Sediment-encased maturation: a novel method for simulating diagenesis in organic fossil preservation. Palaeontology 62, 135-150. Exceptional fossils can preserve diagenetically-altered biomolecules. Understanding the pathways that lead to such preservation is vital to utilizing fossil information in evolutionary and palaeoecological studies. Experimental taphonomy explores the stability of tissues during microbial/autolytic decay or their molecular stability through maturation under high pressure and temperature. Maturation experiments often take place inside sealed containers, preventing the loss of labile, mobile or volatile molecules. However, wrapping tissues inside aluminium foil, for example, can create too open a system, leading to loss of both labile and recalcitrant materials. We present a novel experimental procedure for maturing tissues under elevated pressure/temperature inside compacted sediment. In this procedure, porous sediment allows maturation breakdown products to escape into the sediment and maturation chamber, while recalcitrant, immobile components are contained, more closely mimicking the natural conditions of fossilization. To test the efficacy of this procedure in simulating fossil diagenesis, we investigate the differential survival of melanosomes relative to proteinaceous tissues through maturation of fresh lizard body parts and feathers. Macro- and ultrastructures are then compared to fossils. Similar to many carbonaceous exceptional fossils, the resulting organic components are thin, dark films composed mainly of exposed melanosomes resting on the sediment in association with darkened bones. Keratinous, muscle, collagenous and adipose tissues appear to be lost. Such results are consistent with predictions derived from non-sediment-encased maturation experiments and our understanding of biomolecular stability. These experiments also suggest that organic preservation is largely driven by the original molecular composition of the tissue and the diagenetic stability of those molecules, rather than the tissue's decay resistance alone; this should be experimentally explored in the future.Sakaya, K., Salam, D.A., Campo, P., 2019. Assessment of crude oil bioremediation potential of seawater and sediments from the shore of Lebanon in laboratory microcosms. Science of The Total Environment 660, 227-235. the planned oil and gas exploration activities off the coast of Lebanon, the risk of shoreline contamination with crude oil spills has become a major concern. This study aimed at assessing the crude oil bioremediation potential of the chronically polluted Lebanese shores in light of the continuous discharge of nutrient-rich sewage into the Mediterranean Sea and the long-lasting absence of proper sewage treatment systems. It was anticipated that, with the high pollution levels of the coastline, background concentrations of nutrients would be sufficient to sustain high intrinsic biodegradation rates without human intervention. Biodegradation experiments were conducted using crude oil-spiked beach sediments and seawater under natural attenuation and biostimulation conditions. The experiments were conducted at 18 and 28?°C to account for seasonal variation in temperature, background nutrient levels, and microbial communities. The biodegradability of oil constituents – namely alkanes and polycyclic aromatic hydrocarbons (PAHs), was monitored over a 42-day period using gas chromatography–mass spectrometry (GC–MS). Under biostimulation conditions, significant enhancement in the overall biodegradation rates of alkanes and PAHs was observed in seawater at 18 and 28?°C, while little to no improvement was measured at both temperatures in sediments where background nutrient levels were sufficient to induce near maximum intrinsic biodegradation rates. Under both natural attenuation and biostimulation treatments, the increase in temperature increased the oil biodegradation rates in sediment and seawater microcosms. In both instances, the overall trend in the biodegradation of individual alkanes and PAHs suggested a typical decrease in biodegradation rates with the increase in carbon number/rings and alkyl groups.Samokhin, A.S., Sotnezova, K.M., Revelsky, I.A., 2018. Use of molecular weight and elemental composition as an additional constraint in library search. Journal of Analytical Chemistry 73, 1353-1356. of organic compounds based only on searching against electron ionization mass spectral libraries is tentative. To increase the reliability of the identification, additional information should be used. Gas chromatographic retention indices, in addition to mass spectra, are most often used. Molecular weight and elemental composition is less frequently used, because additional experiments are required to determine these characteristics. In the present paper, we examined the influence of the molecular weight, elements present in a molecule and molecular formula on the results of the library search. It is shown that, determination of the nominal mass or molecular formula slightly increases efficiency of the library search (for example, probability that the correct compound occupies the first position in the list of possible candidates increases by only 2.8 and 3.0% respectively). On the other hand, use of additional constraints in the library search can significantly reduce the number of possible candidates and simplify predicting the absence of compound in the database.Samylina, O.S., 2018. Use of morphology of halophilic and alkaliphilic cyanobacteria as a criterion for detection of soda conditions in the past. Paleontological Journal 52, 1162-1171. modern soda lakes as relict biotopes, the analogs of which could be widespread in the Precambrian Era, are considered in the context of two hypotheses: “soda ocean” and “soda continent.” The diversity of modern halophilic and alkaliphilic cyanobacteria has been analyzed in order to reveal the morphological forms which have paleo-analogs that could be used as indicators of soda conditions in the Precambrian.Sanchez-Garcia, L., Fernandez-Martinez, M.A., García-Villadangos, M., Blanco, Y., Cady, S.L., Hinman, N., Bowden, M.E., Pointing, S.B., Lee, K.C., Warren-Rhodes, K., Lacap-Bugler, D., Cabrol, N.A., Parro, V., Carrizo, D., 2019. Microbial biomarker transition in high-altitude sinter mounds from El Tatio (Chile) through different stages of hydrothermal activity. Frontiers in Microbiology 9, 3350. doi: 10.3389/fmicb.2018.03350. springs support microbial communities at elevated temperatures in an ecosystem with high preservation potential that makes them interesting analogs for early evolution of the biogeosphere. The El Tatio geysers field in the Atacama Desert has astrobiological relevance due to the unique occurrence of geothermal features with steep hydrothermal gradients in an otherwise high altitude, hyper-arid environment. We present here results of our multidisciplinary field and molecular study of biogeochemical evidence for habitability and preservation in silica sinter at El Tatio. We sampled three morphologically similar geyser mounds characterized by differences in water activity (i.e., episodic liquid water, steam, and inactive geyser lacking hydrothermal activity). Multiple approaches were employed to determine (past and present) biological signatures and dominant metabolism. Lipid biomarkers indicated relative abundance of thermophiles (dicarboxylic acids) and sulfate reducing bacteria (branched carboxylic acids) in the sinter collected from the liquid water mound; photosynthetic microorganisms such as cyanobacteria (alkanes and isoprenoids) in the steam sinter mound; and archaea (squalane and crocetane) as well as purple sulfur bacteria (cyclopropyl acids) in the dry sinter from the inactive geyser. The three sinter structures preserved biosignatures representative of primary (thermophilic) and secondary (including endoliths and environmental contaminants) microbial communities. Sequencing of environmental 16S rRNA genes and immuno-assays generally corroborated the lipid-based microbial identification. The multiplex immunoassays and the compound-specific isotopic analysis of carboxylic acids, alkanols, and alkanes indicated that the principal microbial pathway for carbon fixation in the three sinter mounds was through the Calvin cycle, with a relative larger contribution of the reductive acetyl-CoA pathway in the dry system. Other inferred metabolic traits varied from the liquid mound (iron and sulfur chemistry), to the steam mound (nitrogen cycle), to the dry mound (perchlorate reduction). The combined results revealed different stages of colonization that reflect differences in the lifetime of the mounds, where primary communities dominated the biosignatures preserved in sinters from the still active geysers (liquid and steam mounds), in contrast to the surviving metabolisms and microbial communities at the end of lifetime of the inactive geothermal mound.Sánchez, M., Santamarina, C., Teymouri, M., Gai, X., 2018. Coupled numerical modeling of gas hydrate-bearing sediments: From laboratory to field-scale analyses. Journal of Geophysical Research: Solid Earth 123, 10,326-10,348. Methane hydrates are ice-like compounds made of gas methane and water. Hydrates are stable under low-temperature and high-pressure conditions constraining their occurrence in sediments to marine and permafrost settings. A shift from the stability condition triggers an endothermic hydrate dissociation with the associated release of gas and water, impacting (among others) on sediment pore pressure, temperature, and deformations. Therefore, the behavior of hydrate-bearing sediments (HBS) is controlled by strongly coupled thermo-hydro-chemo-mechanical actions. The analysis of available data from past field and laboratory experiments and the optimization of future field production studies require a formal and robust numerical framework able to capture the complex behavior of this type of soil. In this paper we used a fully coupled thermo-hydro-mechanical framework to study different problems involving HBS, from laboratory experiments involving natural hydrate samples to gas production tests. We also develop an analytical solution for the case of gas production via radial depressurization from a confined HBS reservoir. The analyses show the complexity of the thermo-hydro-mechanical phenomena associated with this type of system and contribute to better understand the behavior of HBS.Santos, I.C., Hildenbrand, Z.L., Schug, K.A., 2019. A review of analytical methods for characterizing the potential environmental impacts of unconventional oil and gas development. Analytical Chemistry 91, 689-703. oil and gas extraction (UOG) has expanded rapidly across the United States, as it has become an established technique for recovery of oil and gas from low permeability shales. There are more than 900?000 active oil and gas wells in the United States, and more than 130?000 have been drilled since 2010.(1) The U.S. Energy Information Administration (EIA) estimates that, in 2017, about 16.76 trillion cubic feet (Tcf) of dry natural gas was produced from shale resources in the United States, including the Bakken (North Dakota and Montana), Niobrara (Colorado), Marcellus and Utica (Pennsylvania, Ohio, and West Virginia), Haynesville (Louisiana and East Texas), Eagle Ford (South Texas), and Permian Basin (West Texas and Southeast New Mexico) shale plays, as shown in Figure 1.(2)Hydraulic fracturing facilitates the extraction of oil and gas through the injection of aqueous solutions and suspensions at high pressure (480–850 bar); this process creates fractures in shale formations.(4) The required fluids are comprised of 98–99.5% of water with the addition of sand and chemical additives.(4,5) The selection of these chemical additives depends on the type of drilling mud used and on the geologic conditions. These chemicals include biocides to control microbial growth, friction reducers to reduce friction, gellants to increase viscosity, surfactants to reduce surface tension, oxygen scavengers to prevent corrosion, and proppants to keep the fractures open and to maintain a stable flow.(6) Currently, (7) contains the most comprehensive data set on chemicals used in hydraulic fracturing. Some examples are given in Table 1. Nevertheless, to maintain intellectual propriety, oil and gas companies (and/or their suppliers) do not often provide complete information on the additives used, and this creates challenges in terms of determining the exposure safety, efficacy of treatment modalities, and/or the byproducts present in wastewater or contamination events.After hydraulic stimulation, waste fluid returns to the surface due to the high pressures in the well. This fluid, referred to as flowback water, is wastewater that contains high levels of dissolved solids, salts, and fracturing chemicals. When the flowback finishes, fluid that is within the oil or gas-producing formation can be recovered, which is called produced water. This produced water has high concentrations of salt and can contain harmful levels of metals and radioactivity.(4,6) When they return to the surface, these waste streams must be disposed of, treated, and/or reused.The environmental implications of UOG remain a complex and polarizing topic.(8) Surface water,(9?11) groundwater,(12?20) soil,(21?24) and air(25?31) are potentially subject to contamination from surface spills, transport of fluids through microscale annular fissures in UOG gas wells, gas emissions, and the physical mobilization of ions from scale/rust formations.(9,20,32) Understanding the causes of potential contamination is therefore important to develop responsible energy extraction and environmental stewardship practices. The development of analytical techniques to help provide this understanding is vital. This is a field that is still growing, as some factors still limit the research performed. Groundwater and produced water samples are often very difficult to obtain, and funding for this type of research is currently inadequate. The majority of groundwater samples that have been analyzed as part of most published monitoring studies have been obtained mainly from residential wells, which requires the participation of landowners/well owners. The variability in the willingness to participate, based on the different views and beliefs of those approached to obtain samples, is a confounding factor that may be perceived as experimental bias. Additionally, not all densely populated areas experiencing UOG have water wells, which hinders the ability to perform high-resolution mapping of those areas.The economics of this research also vary depending on who is performing it (academic, commercial, or governmental laboratories). The lack of funding in this field slows down the development of high-resolution techniques for the multiparametric determination of hydraulic fracturing compounds. Furthermore, the lack of communication by the industry as a whole (with some exceptions) also limits the development of environmental impact studies. A better line of communication between academic and private sector partners could provide insight on sampling times in order to align analyses with different aspects of the UOG operations process and what chemicals should be avoided and replaced. Overall, these are all difficulties that limit the research performed in this field and its advancement.Saxena, N., Goswami, A., Dhodapkar, P.K., Nihalani, M.C., Mandal, A., 2019. Bio-based surfactant for enhanced oil recovery: Interfacial properties, emulsification and rock-fluid interactions. Journal of Petroleum Science and Engineering 176, 299-311. surfactants are very effective for application in enhanced oil recovery (EOR) in sandstone reservoirs because of their promising surface-active properties. Considering the non-biodegradability of some of the commercial surfactants, the present study deals with an anionic surfactant synthesized from naturally occurring soap-nut oil with excellent interfacial properties for application in EOR. The soap-nut surfactant showed the promising properties of interfacial tension (IFT) reduction, emulsification, rock wettability alteration, which are desirable for its application in EOR. An ultra-low IFT value of 2.123?×?10?2?mN/m between crude oil and surfactant solution was obtained at critical micelle concentration (CMC), which was further reduced to 2.037?×?10?3?mN/m at optimum salinity. Phase behaviour studies showed the formation of Winsor III emulsion phase which is beneficial for recovery of the trapped oil from the fine pores of the reservoir by miscibility mechanism. The surfactant exhibited favourable rock-wetting ability from oil-wet rock to water-wet condition. The loss of surfactant by adsorption on the rock surface was studied, and the adsorption data were analysed by Langmuir and Freundlich models. Injection of a small pore volume of surfactant-slug augmented with polymer slug as mobility buffer recovered more than 30% of original oil in place (OOIP) after the conventional water-flooding.Schiffer, J.M., Mael, L.E., Prather, K.A., Amaro, R.E., Grassian, V.H., 2018. Sea spray aerosol: Where marine biology meets atmospheric chemistry. ACS Central Science 4, 1617-1623. aerosols have long been known to alter climate by scattering incoming solar radiation and acting as seeds for cloud formation. These processes have vast implications for controlling the chemistry of our environment and the Earth’s climate. Sea spray aerosol (SSA) is emitted over nearly three-quarters of our planet, yet precisely how SSA impacts Earth’s radiation budget remains highly uncertain. Over the past several decades, studies have shown that SSA particles are far more complex than just sea salt. Ocean biological and physical processes produce individual SSA particles containing a diverse array of biological species including proteins, enzymes, bacteria, and viruses and a diverse array of organic compounds including fatty acids and sugars. Thus, a new frontier of research is emerging at the nexus of chemistry, biology, and atmospheric science. In this Outlook article, we discuss how current and future aerosol chemistry research demands a tight coupling between experimental (observational and laboratory studies) and computational (simulation-based) methods. This integration of approaches will enable the systematic interrogation of the complexity within individual SSA particles at a level that will enable prediction of the physicochemical properties of real-world SSA, ultimately illuminating the detailed mechanisms of how the constituents within individual SSA impact climate.Schout, G., Griffioen, J., Hassanizadeh, S.M., Cardon de Lichtbuer, G., Hartog, N., 2019. Occurrence and fate of methane leakage from cut and buried abandoned gas wells in the Netherlands. Science of The Total Environment 659, 773-782. leakage caused by well integrity failure was assessed at 28 abandoned gas wells and 1 oil well in the Netherlands, which have been plugged, cut and buried to below the ground surface (≥3?mbgl). At each location, methane concentrations were thoroughly scanned at the surface. A static chamber setup was used to measure methane flow rates from the surface as well as from 1?m deep holes drilled using a hand auger. An anomalously high flow rate from 1?m depth combined with isotopic confirmation of a thermogenic origin revealed ongoing leakage at 1 of the 29 wells (3.4%), that had gone undetected by surficial measurements. Gas fluxes at the other sites were due to shallow production of biogenic methane. Detailed investigation at the leaking well (MON-02), consisting of 28 flux measurements conducted in a 2?×?2 m grid from holes drilled to 1 and 2?m depth, showed that flux magnitude was spatially heterogeneous and consistently larger at 2?m depth compared to 1?m. Isotopic evidence revealed oxidation accounted for roughly 25% of the decrease in flux towards the surface. The estimated total flux from the well (443?g?CH4?hr?1) was calculated by extrapolation of the individual flow rate measurements at 2?m depth and should be considered an indicative value as the validity of the estimate using our approach requires confirmation by modelling and/or experimental studies. Together, our findings show that total methane emissions from leaking gas wells in the Netherlands are likely negligible compared to other sources of anthropogenic methane emissions (e.g. <1% of emissions from the Dutch energy sector). Furthermore, subsurface measurements greatly improve the likelihood of detecting leakage at buried abandoned wells and are therefore essential to accurately assess their greenhouse gas emissions and explosion hazards.Schuller, J.M., Birrell, J.A., Tanaka, H., Konuma, T., Wulfhorst, H., Cox, N., Schuller, S.K., Thiemann, J., Lubitz, W., Sétif, P., Ikegami, T., Engel, B.D., Kurisu, G., Nowaczyk, M.M., 2019. Structural adaptations of photosynthetic complex I enable ferredoxin-dependent electron transfer. Science 363, 257-260.: Photosynthetic complex I enables cyclic electron flow around photosystem I, a regulatory mechanism for photosynthetic energy conversion. We report a 3.3-angstrom-resolution cryo–electron microscopy structure of photosynthetic complex I from the cyanobacterium Thermosynechococcus elongatus. The model reveals structural adaptations that facilitate binding and electron transfer from the photosynthetic electron carrier ferredoxin. By mimicking cyclic electron flow with isolated components in vitro, we demonstrate that ferredoxin directly mediates electron transfer between photosystem I and complex I, instead of using intermediates such as NADPH (the reduced form of nicotinamide adenine dinucleotide phosphate). A large rate constant for association of ferredoxin to complex I indicates efficient recognition, with the protein subunit NdhS being the key component in this process.Editor's Summary. Plugging into the pump: Photosynthetic organisms use light to fix carbon dioxide in a process that requires both chemical reducing equivalents and adenosine triphosphate (ATP). Balancing the ratio of these inputs is accomplished by a short circuit in electron flow through photosynthetic complex I, a proton pump that contributes to ATP production but does not increase net reducing equivalents in the cell. Schuller et al. solved a cryo–electron microscopy structure of photosynthetic complex I (see the Perspective by Brandt) and went on to reconstitute electron transfer using the electron carrier protein ferredoxin.Schulting, R.J., le Roux, P., Gan, Y.M., Pouncett, J., Hamilton, J., Snoeck, C., Ditchfield, P., Henderson, R., Lange, P., Lee-Thorp, J., Gosden, C., Lock, G., 2019. The ups & downs of Iron Age animal management on the Oxfordshire Ridgeway, south-central England: A multi-isotope approach. Journal of Archaeological Science 101, 199-212. hillforts of the Oxfordshire Ridgeway in south-central England have been interpreted as central places in the Early/Middle Iron Age, ca. 600–100 BCE, serving, among other functions, to integrate the management of animals, particularly sheep, between the upland Chalk downs and the adjacent low-lying Vale of the White Horse. Since these landforms differ geologically and pedologically, they lead to distinct isotopic ratios in the biosphere and so present the potential to investigate animal management practices in some detail. Here, we report the results of a multi-isotope study on domestic fauna (cattle, sheep and pig) within a very constrained study area, with the aim of testing the hypothesis that the Ridgeway's hillforts were placed to control and coordinate the movement of sheep between the Chalk and the Vale. However, the results suggest a different scenario. Bone collagen δ15N results indicate that cattle and sheep were both kept locally. Strontium isotopes, conversely, indicate that, while sheep and pigs were raised locally, cattle appear to have been mainly kept in the Vale during at least the first year of their lives. The apparent discrepancy between the two isotopes can be reconciled by the different periods of life represented by enamel and bone collagen measurements, with the movement of cattle onto the Ridgeway in their second or third year of life. Sequential measurements of δ13C and δ15N in dentine, and of δ13Cc and δ18Oc in enamel, provide further detail on the management of cattle, and offer some support for the above scenario. Early/Middle Iron Age stock-keeping in south-central England was complex, being integrated in some respects but distinct in others. The study demonstrates the level of detail it is possible to achieve with a multi-isotope approach to animal management practices in prehistory. The focus on a micro-region contrasts with, or rather complements, studies addressing larger-scale movement of animals in the past.Schulz, F., Commodo, M., Kaiser, K., De Falco, G., Minutolo, P., Meyer, G., D`Anna, A., Gross, L., 2019. Insights into incipient soot formation by atomic force microscopy. Proceedings of the Combustion Institute 37, 885-892. soot particles can have significant impact on climate, environment and human health. Thus, understanding the processes governing the formation of soot particles in combustion is a topic of ongoing research. In this study, high-resolution atomic force microscopy (AFM) was used for direct imaging of the building blocks forming the particles in the early stages of soot formation. Incipient soot particles were collected right after the particle nucleation zone of a slightly sooting ethylene/air laminar premixed flame at atmospheric pressure and analyzed by AFM after a rapid sublimation procedure. Our data shed light on one of the most complex and still debated aspect on soot formation, i.e., the nucleation process. The molecular constituents of the initial particles have been individually analyzed in detail in their chemical/structural characteristics. Our data demonstrate the large complexity/variety of the aromatic compounds which are the building blocks of the initial soot particles. Nevertheless, some fundamental and specific characteristics have been clearly ascertained. These include a significant presence of penta-rings as opposed to the purely benzenoid aromatic compounds and the noticeable presence of aliphatic side-chains. In addition, there were indications for the presence of persistent π radicals. Incipient soot was also investigated by Raman spectroscopy, the results of which agreed in terms of chemical and structural composition of the particles with those obtained by AFM.Schwaferts, C., Niessner, R., Elsner, M., Ivleva, N.P., 2019. Methods for the analysis of submicrometer- and nanoplastic particles in the environment. TrAC Trends in Analytical Chemistry 112, 52-65. is an emerging topic of relevance in environmental science. The analytical methods for microplastic have a particle size limit of a few micrometers so that new methods have to be developed to cover the nanometer range. This contribution reviews the progress in environmental nanoplastic analysis and critically evaluates which techniques from nanomaterial analysis may potentially be adapted to close the methodological gap. A roadmap is brought forward for the whole analytical process from sample treatment to particle characterization. This includes a critical review of (i) methods for analyte extraction and preconcentration from various environmental matrices; (ii) methods for the separation of the nanoplastic into specific size fractions; (iii) light scattering techniques and various types of microscopy to characterize the particle fractions; (iv) chemical identification of particles to validate the obtained data. For these methods, we will discuss prospects and limitations to develop analytical protocols for specific sampling scenarios.Scott, K.M., Leonard, J.M., Boden, R., Chaput, D., Dennison, C., Haller, E., Harmer, T.L., Anderson, A., Arnold, T., Budenstein, S., Brown, R., Brand, J., Byers, J., Calarco, J., Campbell, T., Carter, E., Chase, M., Cole, M., Dwyer, D., Grasham, J., Hanni, C., Hazle, A., Johnson, C., Johnson, R., Kirby, B., Lewis, K., Neumann, B., Nguyen, T., Nino Charari, J., Morakinyo, O., Olsson, B., Roundtree, S., Skjerve, E., Ubaldini, A., Whittaker, R., 2019. Diversity in CO2-concentrating mechanisms among chemolithoautotrophs from the genera Hydrogenovibrio, Thiomicrorhabdus, and Thiomicrospira, ubiquitous in sulfidic habitats worldwide. Applied and Environmental Microbiology 85, Article e02096-18.: Members of the genera Hydrogenovibrio, Thiomicrospira, and Thiomicrorhabdus fix carbon at hydrothermal vents, coastal sediments, hypersaline lakes, and other sulfidic habitats. The genome sequences of these ubiquitous and prolific chemolithoautotrophs suggest a surprising diversity of mechanisms for the uptake and fixation of dissolved inorganic carbon (DIC); these mechanisms are verified here. Carboxysomes are apparent in the transmission electron micrographs of most of these organisms but are lacking in Thiomicrorhabdus sp. strain Milos-T2 and Thiomicrorhabdus arctica, and the inability of Thiomicrorhabdus sp. strain Milos-T2 to grow under low-DIC conditions is consistent with the absence of carboxysome loci in its genome. For the remaining organisms, genes encoding potential DIC transporters from four evolutionarily distinct families (Tcr_0853 and Tcr_0854, Chr, SbtA, and SulP) are located downstream of carboxysome loci. Transporter genes collocated with carboxysome loci, as well as some homologs located elsewhere on the chromosomes, had elevated transcript levels under low-DIC conditions, as assayed by reverse transcription-quantitative PCR (qRT-PCR). DIC uptake was measureable via silicone oil centrifugation when a representative of each of the four types of transporter was expressed in Escherichia coli. The expression of these genes in the carbonic anhydrase-deficient E. coli strain EDCM636 enabled it to grow under low-DIC conditions, a result consistent with DIC transport by these proteins. The results from this study expand the range of DIC transporters within the SbtA and SulP transporter families, verify DIC uptake by transporters encoded by Tcr_0853 and Tcr_0854 and their homologs, and introduce DIC as a potential substrate for transporters from the Chr family.Importance: Autotrophic organisms take up and fix DIC, introducing carbon into the biological portion of the global carbon cycle. The mechanisms for DIC uptake and fixation by autotrophic Bacteria and Archaea are likely to be diverse but have been well characterized only for “Cyanobacteria.” Based on genome sequences, members of the genera Hydrogenovibrio, Thiomicrospira, and Thiomicrorhabdus have a variety of mechanisms for DIC uptake and fixation. We verified that most of these organisms are capable of growing under low-DIC conditions, when they upregulate carboxysome loci and transporter genes collocated with these loci on their chromosomes. When these genes, which fall into four evolutionarily independent families of transporters, are expressed in E. coli, DIC transport is detected. This expansion in known DIC transporters across four families, from organisms from a variety of environments, provides insight into the ecophysiology of autotrophs, as well as a toolkit for engineering microorganisms for carbon-neutral biochemistries of industrial importance.Sepehri, M., Moradi, B., Emamzadeh, A., Mohammadi, A.H., 2019. Experimental study and numerical modeling for enhancing oil recovery from carbonate reservoirs by nanoparticle flooding. Oil & Gas Science and Technology – Revue d’IFP Energies nouvelles 74, Article 5., nanotechnology has become a very attractive subject in Enhanced Oil Recovery (EOR) researches. In the current study, a carbonate system has been selected and first the effects of nanoparticles on the rock and fluid properties have been experimentally investigated and then the simulation and numerical modeling of the nanofluid injection for enhanced oil recovery process have been studied. After nanofluid treatment, experimental results have shown wettability alteration. A two-phase flow mathematical model and a numerical simulator considering wettability alteration have been developed. The numerical simulation results show that wettability alteration from oil-wet to water-wet due to presence of nanoparticles can lead to 8–10% increase in recovery factor in comparison with normal water flooding. Different sensitivity analyses and injection scenarios have been considered and assessed. Using numerical modeling, wettability alteration process and formation damage caused by entrainment and entrapment of nanoparticles in porous media have been proved. Finally, the net rate of nanoparticles’ loss in porous media has been investigated.Sergeev, V.N., 2018. The biostratigraphic paradox of Precambrian cyanobacteria: Distinguishing the succession of microfossil assemblages and evolutionary changes observed among Proterozoic prokaryotic microorganisms. Paleontological Journal 52, 1148-1161. cyanobacteria demonstrate unprecedented evolutionary conservatism and have remained practically unchanged for the last 2 Ga, considering that ancient forms have counterparts among genera and even species of modern microorganisms. However, Proterozoic cyanobacteria and other prokaryotes form unique assemblages of restricted geochronological range and broad spatial distribution. The most remarkable of these assemblages are the Gunflint-type Paleoproterozoic microbiotas and the Early Riphean Archaeoellipsoides-dominant Kotuikan-type assemblages. Their observed taxonomic uniqueness and short geochronological ranges reflect irreversible changes in the Earth’s global environments, rather than evolutionary innovations. Nonetheless, the fossil blue-green algae demonstrate some evolutionary changes throughout the Proterozoic: the stalked cyanobacteria Polybessurus appeared in the Middle Riphean and the spiral cylindrical cyanobacteria Obruchevella emerged in the Late Riphean.Service, R.F., 2019. Seeing the dawn. Science 363, 116-119. cataclysm may have jump-started life on Earth. A new scenario suggests that some 4.47 billion years ago—a mere 60 million years after Earth took shape and 40 million years after the moon formed—a moon-size object sideswiped Earth and exploded into an orbiting cloud of molten iron and other debris.The metallic hailstorm that ensued likely lasted years, if not centuries, ripping oxygen atoms from water molecules and leaving hydrogen behind. The oxygens were then free to link with iron, creating vast rust-colored deposits of iron oxide across our planet's surface. The hydrogen formed a dense atmosphere that likely lasted 200 million years as it ever so slowly dissipated into space.After things cooled down, simple organic molecules began to form under the blanket of hydrogen. Those molecules, some scientists think, eventually linked up to form RNA, a molecular player long credited as essential for life's dawn. In short, the stage for life's emergence was set almost as soon as our planet was born.That scenario captivated participants at an October 2018 conference here, where geologists, planetary scientists, chemists, and biologists compared notes on the latest thinking on how life got its start. No rocks or other direct evidence remain from the supposed cataclysm. Its starring role is inferred because it would solve a bevy of mysteries, says Steven Benner, an origin of life researcher at the Foundation for Applied Molecular Evolution in Alachua, Florida, who organized the Origins of Life Workshop.The metal-laden rain accounts for the distribution of metals across our planet's surface today. The hydrogen atmosphere would have favored the emergence of the simple organic molecules that later formed more complex molecules such as RNA. And the planetary crash pushes back the likely birthdate for RNA, and possibly life's emergence, by hundreds of millions of years, which better aligns with recent geological evidence suggesting an early emergence of life.The impact scenario joins new findings from laboratory experiments suggesting how the chemicals spawned on early Earth might have taken key steps along the road to life—steps that had long baffled researchers. Many in the field see a consistent narrative describing how and when life was born starting to take shape. “Fifteen years ago, we only had a few hazy ideas” about how life may have come about, says Andrej Lupták, a chemist at the University of California (UC), Irvine, who attended the meeting. “Now, we're seeing more and more pieces come together.”The case isn't settled, Lupták and others say. Researchers still disagree, for example, over which chemical path most likely gave rise to RNA and how that RNA combined with proteins and fats to form the earliest cells. Nevertheless, Benner says, “The field is in a new place. There is no question.”Life As We Know It: likely emerged from an “RNA world,” many researchers agree. In modern cells, DNA, RNA, and proteins play vital roles. DNA stores heritable information, RNA ferries it inside cells, and proteins serve as chemical workhorses. The production of each of those biomolecules requires the other two. Yet, the idea that all three complex molecules arose simultaneously seems implausible.Since the 1960s, a leading school of thought has held that RNA arose first, with DNA and proteins evolving later. That's because RNA can both serve as a genetic code and catalyze chemical reactions. In modern cells, RNA strands still work alongside proteins at the heart of many crucial cellular machines.In recent years, chemists have sketched out reactions that could have produced essential building blocks for RNA and other compounds. In 2011, for example, Benner and his colleagues showed how boron-containing minerals could have catalyzed reactions of chemicals such as formaldehyde and glycolaldehyde, which were probably present on early Earth, to produce the sugar ribose, an essential component of RNA. Other researchers have laid out how ribose may have reacted with other compounds to give rise to individual RNA letters, or nucleosides.But critics such as Robert Shapiro, a biochemist at New York University in New York City who died in 2011, often pointed out that when researchers produced one pre-RNA chemical component or another, they did so under controlled conditions, adding purified reagents in just the right sequence. How all those steps could have occurred in the chaotic environment of early Earth is unclear at best. “The analogy that comes to mind is that of a golfer, who having played a golf ball through an 18-hole course, then assumed that the ball could also play itself around the course in his absence,” Shapiro wrote in 2007 in Scientific American. He favored a “metabolism first” view of life's origin, in which energetic small molecules trapped inside lipidlike membranes or other compartments established chemical cycles resembling metabolism, which transformed into more complex networks. Other researchers, meanwhile, have argued that simple proteins were a more likely driver of early life because their amino acid building blocks are far simpler than the nucleotides in RNA.Arguments have sometimes been heated. At a 2008 meeting on the origin of life in Ventura, California, Shapiro and John Sutherland, a chemist at the University of Cambridge in the United Kingdom, wound up shouting at each other. “Bob was very critical about published routes to prebiotic molecules,” Sutherland says. If the chemistry wasn't ironclad, “he felt it failed.”Today, Benner says, “The amount of yelling has gone down.” A steady stream of new data has bolstered scenarios for how RNA could have arisen. For example, although Benner and his colleagues had previously shown how ribose may have formed, they could not explain how some of its ingredients—namely, the highly reactive small molecules formaldehyde, glycolaldehyde, and glyceraldehyde—could have survived. Geochemists have long thought that reactions sparked by lightning and ultraviolet (UV) light could have produced such compounds. However, Benner says, “There's no way to build up a reservoir” of those compounds. They can react with one another, devolving into a tarlike glop.Benner now has a possible solution, which builds on recent work suggesting early Earth had a wet-dry cycle. On the basis of evidence from tiny, almost indestructable mineral crystals called zircons, researchers think a modest amount of dry land was occasionally doused with rain. In a not-yet-published study, he and colleagues in the United States and Japan have found that sulfur dioxide, which would have belched from volcanoes on early Earth, reacts with formaldehyde to produce a compound called hydroxymethanesulfonate (HMS). During dry times, HMS would have accumulated on land “by the metric ton,” Benner says. The reverse reaction would have happened more slowly, regenerating formaldehyde. Then, when rains came, it could have washed in a steady trickle into puddles and lakes, where it could react to form other small organic molecules essential for building RNA. Similar processes, Benner says, could have provided a steady supply of glycolaldehyde and glyceraldehyde as well.The sugar ribose is only one piece of RNA. The molecule also strings together four ring-shaped bases, which comprise the letters of the genetic code: cytosine (C), uracil (U), adenine (A), and guanine (G). Making them requires a supply of electron-rich nitrogen compounds, and identifying a plausible source for those has long challenged origin of life researchers. But other recent advances in prebiotic chemistry, which assume a supply of those compounds, have identified a set of reactions that could have produced all four of RNA's genetic letters at the same time and place. In 2009, for example, Sutherland and his colleagues reported a plausible prebiotic reaction for making C and U, chemically related letters known as pyrimidines. Then, in 2016, a team led by chemist Thomas Carell from Ludwig Maximilian University in Munich, Germany, reported coming up with a plausible way to make A and G, known as purines. The trouble was that Sutherland's and Carell's routes to pyrimidines and purines required different reaction conditions, making it difficult to imagine how they could have taken place side by side.At the workshop, Carell reported a possible solution. He and his colleagues found that simple compounds likely present on early Earth could react in several steps to produce pyrimidines. Nickel and other common metals trigger the last step in the sequence by swiping electrons from intermediate compounds, causing them to react with one another. It turns out that gaining electrons enables the metals to then carry out a final step in synthesizing purines. What's more, those steps can produce all four nucleosides in one pot, thereby offering the first plausible explanation for how all four RNA letters could have arisen together.Benner calls Carell's solution very clever. But not everyone is on board. Sutherland notes that those reactions are inefficient; any nucleosides they produced might fall apart faster than they could accumulate. To address that concern, others argue that more stable RNA-like compounds, rather than RNA itself, might have emerged first and helped form the first chemical system that could reproduce itself. Later, those RNA mimics might have given way to more efficient modern biomolecules such as RNA.Whichever route RNA's letters took, other researchers have recently worked out how minerals likely present on early Earth could have added phosphate groups to RNA nucleosides, an essential step toward linking them into long strings of RNA that could then have acted as catalysts and a rudimentary genetic code. And many experiments have confirmed that once RNA chains begin to grow, they can swap RNA letters and even whole sections with other strands, building complexity, variation, and new chemical functions. At the meeting, for example, Niles Lehman, a chemist at Portland State University in Oregon, described experiments in which pairs of 16-letter-long RNA chains, known as 16-mers, rearranged to form 28-mers and 4-mers. “This is how we can go from short things that can be made prebiotically to more complex molecules,” Lehman said. Later, he quipped, “If you give me 8-mers, I'll give you life.”That process may help explain how more complex RNA molecules arose, including those that can propel the synthesis of simple proteins. At the meeting in Atlanta, chemist Ada Yonath presented one such prototypical proteinmaking RNA. Yonath, of the Weizmann Institute of Science in Rehovot, Israel, shared the 2009 Nobel Prize in Chemistry for working out the atomic structure of the ribosome, the complex molecular machine inside today's cells that translates the genetic code into proteins. Yonath's original structure was of a bacterium's ribosome. Since then, she and her colleagues, along with other groups, have mapped the ribosomes of many other species. Modern ribosomes are behemoths, made up of dozens of protein and RNA components. But at their core, all ribosomes have a sinuous string of RNA with a narrow slit through which budding proteins emerge. The structure is virtually identical across species, unchanged after billions of years of evolution.Her group has now synthesized that ribosomal core, which she refers to as the protoribosome. At the meeting, she reported that her team's protoribosome can stitch together pairs of amino acids, the building blocks of proteins. “I think we're seeing back to how life began billions of years ago,” Yonath says.All that is still a long way from demonstrating the emergence of life in a test tube. Nevertheless, Clemens Richert, a chemist at the Institute of Organic Chemistry at the University of Stuttgart in Germany, says the recent progress has been heartening. “We're finding reactions that work,” he says. “But there are still gaps to get from the elements to functional biomolecules.”One major gap is identifying a source for the energetic nitrogen-containing molecules needed to make the RNA bases. Lightning and UV light acting on compounds in the atmosphere may have made enough of them, says Jack Szostak, an origin of life expert at Harvard University. At the meeting, Stephen Mojzsis, a geologist at the University of Colorado in Boulder, argued that the moon-size impact is a more plausible spark.Mojzsis didn't set out to grapple with the origin of life. Rather, he and his colleagues were looking for ways to make sense of a decades-old geological conundrum: the surprising abundance of platinum and related metals in Earth's crust. In the standard picture of Earth's formation, they simply shouldn't be there. The violent assembly of the planet from smaller bodies 4.53 billion years ago would have left it as a boiling sea of magma for millions of years. Dense elements, such as iron, gold, platinum, and palladium, should have sunk to the planet's core, whereas silicon and other light elements floated nearer the surface. Yet as the wares in any jewelry store testify, those metals remain plentiful near the planet's surface. “Precious metals in the crust are thousands of times more abundant than they should be,” Mojzsis says.The long-standing explanation has been that after Earth cooled enough to form a crust, additional metals arrived in a hail of meteors. On the basis of ages of moon rocks brought back by Apollo astronauts, geologists suspected this assault was particularly intense from 3.8 billion to 4.1 billion years ago, a period they refer to as the Late Heavy Bombardment (LHB).But that scenario has problems, Benner says. For starters, fossil evidence of complex microbial mats called stromatolites shows up in rocks just a few hundred million years younger than the hypothetical bombardment. That's a narrow window in which to move from zero organic molecules to full-blown cellular life.Zircons—those tiny, durable crystals—also pose a challenge, says Elizabeth Bell, a geologist at UC Los Angeles. Zircons are hardy enough to have remained intact even as the rocks that originally housed them melted while cycling into and out of the planet's interior.In 2015, Bell and her colleagues reported in the Proceedings of the National Academy of Sciences that zircons dated to 4.1 billion years ago contain flecks of graphitic carbon with a lifelike combination of carbon isotopes—biased toward carbon's lighter isotope over its heavier one. Bell concedes that an as-yet-unknown nonbiological process might account for that isotope mix, but she says it suggests life was already widespread 4.1 billion years ago, before the end of the LHB. Other recent zircon data, including samples from as long ago as 4.32 billion years, hint that very early Earth had both liquid water and dry land, suggesting it was more hospitable to life than originally thought. “We're pushing back further and further the time when life could have been formed on Earth,” Bell says.Mojzsis argues that a moon-size cataclysm 4.47 billion years ago could explain both Earth's veneer of precious metals and an early start for life. In December 2017, he and two colleagues published a set of extensive computer simulations in Earth and Planetary Science Letters showing how the current distribution of metals could have originated in the rain of debris from such an impact. Simone Marchi, a planetary scientist at the Southwest Research Institute in Boulder, and colleagues reached much the same conclusion in a paper the same month in Nature Geoscience. Marchi's team, however, simulated not one moon-size impactor, but several smaller bodies, each about 1000 kilometers across.Whether one impact or a few, those collisions would have melted Earth's silicate crust, an event that appears to be recorded in data on isotopes of uranium and lead, according to Mojzsis. The collisions also would have profoundly affected Earth's early atmosphere. Before the impact, the cooling magma and rocks on the surface would have spurted out gases, such as carbon dioxide, nitrogen, and sulfur dioxide. None of those gases is reactive enough to produce the organic compounds needed to make RNA. But Benner notes the blanket of hydrogen generated by the impact's metallic hail would have formed exactly the kind of chemically reducing atmosphere needed to produce the early organics. Robert Hazen, a geologist at the Carnegie Institution's Geophysical Laboratory in Washington, D.C., agrees that hydrogen could help. With that reducing atmosphere, the wide array of minerals on the planet's surface could have acted as catalysts to propel the chemical reactions needed to make simple organics, Hazen says.Just before the impact, Mojzsis says, “there was no persistent niche for the origin of life.” But after the impact and a brief period of cooling, he adds, “at 4.4 billion years ago, there are settled niches for the propagation of life.”“I'm delighted,” Benner says. “Steve [Mojzsis] is giving us everything we need” to seed the world with prebiotic chemicals. And by eliminating the need for the LHB, the impact scenario implies organic molecules, and possibly RNA and life, could have originated several hundred million years earlier than thought. That would allow plenty of time for complex cellular life to evolve by the time it shows up in the fossil record at 3.43 billion years ago.Not everybody accepts that tidy picture. Even if geologists' new view of early Earth is correct, the RNA world hypothesis remains flawed, says Loren Williams, a physical chemist at the Georgia Institute of Technology here and an RNA world critic who attended the workshop. “I like talking to Steve Benner,” Williams says. “But I don't agree with him.”One major problem with the RNA world, he says, is that it requires a disappearing act. An RNA molecule capable of faithfully copying other RNAs must have arisen early, yet it has vanished. “There's no evidence for such a thing in modern biology,” Williams says, whereas other vestiges of ancient RNA machines abound. The ribosome's RNA core, for example, is virtually unchanged in every life form on the planet. “When biology makes something, it gets taken and used over and over,” Williams notes. Instead of an RNA molecule that can copy its brethren, he says, it's more likely that early RNAs and protein fragments called peptides coevolved, helping each other multiply more efficiently.Advocates of the RNA world hypothesis concede they can't explain how early RNA might have copied itself. “An important ingredient is still missing,” Carell says. Researchers around the globe have designed RNA-based RNA copiers in the lab. But those are long, complex molecules, made from 90 or more RNA bases. And the copiers tend to copy some RNA letters better than others.Still, enough steps of an RNA-first scenario have come into focus to convince advocates that others will follow. “We are running a thought experiment,” says Matthew Powner, a chemist at University College London. “All we can do is decide what we think is the simplest trajectory.”That thought experiment was on full display in the workshop's final session. Ramon Brasser of the Tokyo Institute of Technology, one of Mojzsis's collaborators, stood at the front of a small conference room and drew a timeline of Earth's earliest days. A red slash at 4.53 billion years ago on the left side of Brasser's flip chart marked Earth's initial accretion. Another slash at 4.51 billion years ago indicated the moon's formation. A line at 4.47 billion years ago marked the hypothetical impact of the planetesimal that gave rise to an atmosphere favorable to organic molecules.Benner asked Brasser how long Earth's surface would have taken to cool below 100°C after the impact, allowing liquid water to host the first organic chemical reactions. Probably 50 million years, Brasser said. Excited, Benner rushed up to the timeline and pointed to a spot at 4.35 billion years ago, adding a cushion of extra time. “That's it, then!” Benner exclaimed. “Now we know exactly when RNA emerged. It's there—give or take a few million years.”Seviour, T., Derlon, N., Dueholm, M.S., Flemming, H.-C., Girbal-Neuhauser, E., Horn, H., Kjelleberg, S., van Loosdrecht, M.C.M., Lotti, T., Malpei, M.F., Nerenberg, R., Neu, T.R., Paul, E., Yu, H., Lin, Y., 2019. Extracellular polymeric substances of biofilms: Suffering from an identity crisis. Water Research 151, 1-7. biofilms can be both cause and cure to a range of emerging societal problems including antimicrobial tolerance, water sanitation, water scarcity and pollution. The identities of extracellular polymeric substances (EPS) responsible for the establishment and function of biofilms are poorly understood. The lack of information on the chemical and physical identities of EPS limits the potential to rationally engineer biofilm processes, and impedes progress within the water and wastewater sector towards a circular economy and resource recovery. Here, a multidisciplinary roadmap for addressing this EPS identity crisis is proposed. This involves improved EPS extraction and characterization methodologies, cross-referencing between model biofilms and full-scale biofilm systems, and functional description of isolated EPS with in situ techniques (e.g. microscopy) coupled with genomics, proteomics and glycomics. The current extraction and spectrophotometric characterization methods, often based on the principle not to compromise the integrity of the microbial cells, should be critically assessed, and more comprehensive methods for recovery and characterization of EPS need to be developed.Shalaby, M.R., Jumat, N., Lai, D., Malik, O., 2019. Integrated TOC prediction and source rock characterization using machine learning, well logs and geochemical analysis: Case study from the Jurassic source rocks in Shams Field, NW Desert, Egypt. Journal of Petroleum Science and Engineering 176, 369-380. machine learning methods and well log mathematical models have been used for predicting total organic carbon (TOC) in Jurassic source rock formations in Northwestern Desert, Egypt. Conventional well log data from two wells have been utilized for source rock study of Jurassic source rocks from Khatatba and Ras Qattara formations in the study area. The source rock is first studied based on geochemical parameters, which include assessments on the type and amount of kerogen present within the source rock samples. The Jurassic source rock samples have great generative potential and consist of mixed kerogen type III and kerogen type II-III. TOC content reaches up to 46.90% for Khatatba and 16.80% Ras Qattara. In the second part of this research, we attempt to characterize the Jurassic source rocks by using mathematical well log models and machine learning methods. GR, RHOB and NPHI well log data were used for TOC prediction using both methods. The quantified TOC results show that the R2 values of well log models are above 0.9 for both formations, whereas the machine learning method using Artificial Neural Network showed R2 value of 0.4. The results from the well log models suggest that they are applicable in the study area. This study has proven that well log data can be used with confidence to evaluate organic source quantity of Jurassic rocks in Northwestern Desert in the absence of geochemical data.Shan, J., Zhao, J., Zhang, Y., Liu, L., Wu, F., Wang, X., 2019. Simple and rapid detection of microplastics in seawater using hyperspectral imaging technology. Analytica Chimica Acta 1050, 161-168. (MPs) pollution in marine systems is attracting worldwide attentions, which highlights a pressing need for efficient detection methods. Traditional protocols generally identify the suspected particles individually, which are time-consuming. Hyperspectral imaging technique has emerged as a simple and rapid method to characterize MPs in seawater. However, hyperspectral image consists of amount of redundant and high correlated spectral information, resulting in the Hughes phenomenon for classification. This work aimed to identify MPs from the hyperspectral image using support vector machine (SVM) algorithm, which presents a good performance for analyzing nonlinear and high-dimensional data and is insensitive to the Hughes effect. In this work, SVM was performed to quantify and identify MPs in both of seawater and seawater filtrates. The factors which may affect the accuracy of SVM model were investigated, including organic particles, polymer types and particle sizes. SVM model yielded a satisfactory accuracy for all the tested pure polymers and it presented a highly robust for detecting MPs in a wide range of types and particle sizes. Finally, common household polymers were chosen to validate the developed model. The results illustrate that hyperspectral imaging technology combination with SVM method exhibits a high robustness and recovery rate for MPs detection.Shao, D., Zhang, T., Ko, L.T., Luo, H., Zhang, D., 2019. Empirical plot of gas generation from oil-prone marine shales at different maturity stages and its application to assess gas preservation in organic-rich shale system. Marine and Petroleum Geology 102, 258-270. the degree of gas preservation and loss in shale gas system is critical to evaluate unconventional shale gas potential, particularly in the tectonically faults developed areas. In this study, an empirical plot of gas yields from marine shales at different stages of maturity and residual TOC content is derived from pyrolysis results and applied to evaluate the extent of shale gas loss. Miniature core plugs drilled from immature Barnett mudstone, Eagle Ford limestone, Woodford chert and mudstone samples were isothermally heated at 130?°C, 300?°C, 310?°C, 333?°C, 367?°C, 400?°C, and 425?°C for 72?h under a confining pressure of 68.0?MPa, corresponding to immature, early stage of oil window, main stage of oil window, late stage of oil window, main stage of oil cracking to wet gas, and late stage of oil cracking, respectively. The generated gas yields from marine shales with increasing thermal maturity are evaluated quantitatively by anhydrous closed-system pyrolysis. Experimental results show that gaseous hydrocarbon yields (C1-C5) from type II kerogen-dominated marine shales are linearly proportional to their residual TOC content at each stage of petroleum formation. The regression lines in the plot of generated gas yield and residual TOC content thus represent different gas-generation stages of type II kerogen-dominated marine shales. In the application to three geologic cases, the measured total gas content and present-day TOC content from a variety of shale gas wells with varying thermal maturity levels were incorporated into the empirical plot. And the comparative results show that, the gas contents of these core samples investigated for the low thermal maturity New Albany Shale in the Illinois Basin are somewhat higher than the estimated yield of generated gas from type II kerogen-dominated marine shales at the early stage of oil window, suggesting that microbial gas made contribution to the excess gas content in the New Albany shale gas system and it represents a typical gas mixture containing both early thermogenic gas and biogenic gas. In contrast, significant gas loss was observed in both the high thermal maturity Barnett Shale in the Fort Worth Basin and the overmature Silurian Longmaxi Shale in the Sichuan Basin as compared to each the estimated yield of generated gas. This phenomenon is probably caused by either petroleum expulsion or tectonic dissipation, or coupling of two processes. As for the Silurian Longmaxi Shale, it is estimated that approximately 60%–90% of total generated gas in quantities has been lost in the overmature Silurian Longmaxi shale gas system where industrial gas flow had been achieved. This provides an upper-limit measure to shale gas loss caused by petroleum expulsion and tectonic dissipation throughout geological time.Shen, M., Zhu, Y., Zhang, Y., Zeng, G., Wen, X., Yi, H., Ye, S., Ren, X., Song, B., 2019. Micro(nano)plastics: Unignorable vectors for organisms. Marine Pollution Bulletin 139, 328-331.(nano)plastics, as emerging contaminants, have attracted worldwide attention. Nowadays, the environmental distribution, sources, and analysis methods and technologies of micro(nano)plastics have been well studied and recognized. Nevertheless, the role of micro(nano)plastic particles as vectors for attaching organisms is not fully understood. In this paper, the role of micro(nano)plastics as vectors, and their potential effects on the ecology are introduced. Micro(nano)plastics could 1) accelerate the diffusion of organisms in the environment, which may result in biological invasion; 2) increase the gene exchange between attached biofilm communities, causing the transfer of pathogenic and antibiotic resistance genes; 3) enhance the rate of energy, material and information flow in the environment. Accordingly, the role of microplastics as vectors for organisms should be further evaluated in the future research.Shen, S.-Z., Ramezani, J., Chen, J., Cao, C.-Q., Erwin, D.H., Zhang, H., Xiang, L., Schoepfer, S.D., Henderson, C.M., Zheng, Q.-F., Bowring, S.A., Wang, Y., Li, X.-H., Wang, X.-D., Yuan, D.-X., Zhang, Y.-C., Mu, L., Wang, J., Wu, Y.-S., 2018. A sudden end-Permian mass extinction in South China. GSA Bulletin 131, 205-223. studies of the end-Permian mass extinction have established that it was geologically rapid, but condensed sections have made it difficult to establish the exact timing of the extinction relative to fluctuations in the ocean carbon cycle, oxygen levels, and temperature. Integrated high-precision U-Pb geochronology, biostratigraphy, and chemostratigraphy from a highly expanded section at Penglaitan, Guangxi, South China reveal a sudden end-Permian mass extinction that occurred at 251.939 ± 0.031 Ma, which is temporally coincident with the extinction recorded in Bed 25 of the Meishan section. Despite the significantly expanded nature of the section and extensive collecting of more than ten major marine fossil groups, there is no evidence of a decline of biotic diversity prior to the extinction interval and no Permian-type species survive the extinction at this location. Fossil range data suggest a nearly instantaneous extinction at the top of a narrow stratigraphic interval limited to 31 ± 31 k.y. The extinction was preceded by and/or accompanied by fluctuations in δ13Ccarb and δ13Corg of 2–3‰, and 3–5 °C in seawater temperature. A larger, more rapid seawater temperature rise of 6–8 °C immediately followed the extinction level at Penglaitan. The extinction is spatially associated with a thick unit of tuff and tuffaceous sandstones (Bed 141) indicating massive pyroclastic input. It is correlative with an ash layer (Bed 25) in the deeper water setting at Meishan, where some Permian-type organisms survived the extinction. Our study reveals that the survivability of Permian taxa after the major extinction pulse is variable and dependent upon the severity of environmental perturbation in different sedimentary settings. The sudden extinction may fit a scenario in which the onset of Siberian Traps and South China intensive volcanism ～420 k.y. before the extinction may have diminished the ecological resilience of communities and reduced ecological functions with little change in diversity. In such an environmentally stressed condition, a single environmental disturbance could trigger the sudden collapse of global ecosystems.Shi, J., Zhu, Y., Zhang, Y., Lin, Z., Lv, H.-P., 2018. Volatile composition of Fu-brick tea and Pu-erh tea analyzed by comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry. LWT - Food Science and Technology 103, 27-33. tea is a special type of tea that requires microbial fermentation during the post-fermentation process, and its volatile composition is quite different from other tea kinds. The present study aimed at charactering the volatile composition of two typical Chinese dark teas (Fu-brick tea and Pu-erh tea). Volatile compounds from both teas were extracted and analyzed using simultaneous distillation extraction (SDE) combined with two-dimensional gas chromatography-time-of-flight-mass spectrometry (GC?×?GC-TOFMS). A total of 373 and 408 major aromatic components were tentatively identified in Fu-brick tea and Pu-erh tea, respectively. The relative quantification results showed that ketenes (24.87%), ketones (16.86%), aldehydes (14.36%) and olefine aldehydes (9.11%) were more abundant in Fu-brick teas, while in Pu-erh teas, ketenes accounted for 17.95%, followed by aldehydes (14.51%), ally esters and ketones (11.94% and 10.78%). Multivariate analysis indicated that obvious differences existed in the levels of some aromatic compounds between the two dark teas. Benzaldehyde and benzeneacetaldehyde in Fu-brick teas were considerably lower and accounted for approximately 55% of those in Pu-erh teas; whilst, nonanal and 2-hexenal in Fu-brick tea were twice as high as in Pu-erh tea. The application of pre-enrichment extraction with GC?×?GC-TOFMS analysis gives a thorough view of the aromatic constituents of dark teas.Shi, L., Ma, D., Li, X., Xi, C., Qi, Z., Liu, P., 2019. Analytical modeling of oil production rate during the entire steam-assisted gravity drainage process in heavy oil reservoirs. Journal of Petroleum Science and Engineering 175, 190-199. steam-assisted gravity drainage (SAGD) process is a widely used thermal recovery technique for heavy oil reservoirs worldwide. In addition to numerical simulation methods, analytical models are alternative tools for the prediction and evaluation of heavy oil recovery by SAGD. In this study, a new analytical oil production rate prediction model for the entire SAGD process, including the rising, transition, expanding and depletion stages, is derived based on the movement rules of the steam chamber interface. The main improvements compared with existing analytical models in this work involve the introducing of a transition stage which is between the rising and the expansion stages, the modification of the depletion stage, the consideration of homogeneity with anisotropy, and the modification of the initial slope angle and shape factors which vary with reservoir parameters and steam injection parameters. Furthermore, the new analytical model is validated against with a relatively complete analytical model and numerical simulation models under field conditions. The results show that the new analytical model can predict the oil rate during the entire SAGD process more accurately than other available analytical models and with high agreement with numerical simulation results and field data. The results also show that the continuity of oil rate is improved by introducing the transition stage. The anisotropy of the permeability cannot be ignored, because it affects the peak oil rate and plateau time of the SAGD process. Moreover, the new model can quickly diagnose the phase of the steam chamber development, which provides guidance for the follow-up adjustment in heavy oil field application.Shi, M., Fisher, J.B., Phillips, R.P., Brzostek, E.R., 2019. Neglecting plant–microbe symbioses leads to underestimation of modeled climate impacts. Biogeosciences 16, 457-465. extent to which terrestrial ecosystems slow climate change by sequestering carbon hinges in part on nutrient limitation. We used a coupled carbon–climate model that accounts for the carbon cost to plants of supporting nitrogen-acquiring microbial symbionts to explore how nitrogen limitation affects global climate. To do this, we first calculated the reduction in net primary production due to the carbon cost of nitrogen acquisition. We then used a climate model to estimate the impacts of the resulting increase in atmospheric CO2 on temperature and precipitation regimes. The carbon costs of supporting symbiotic nitrogen uptake reduced net primary production by 8.1?Pg?C?yr?1, with the largest absolute effects occurring in tropical forest biomes and the largest relative changes occurring in boreal and alpine biomes. Globally, our model predicted relatively small changes in climate due to the carbon cost of nitrogen acquisition with temperature increasing by 0.1?°C and precipitation decreasing by 6?mm?yr?1. However, there were strong regional impacts, with the largest impact occurring in boreal and alpine ecosystems, where such costs were estimated to increase temperature by 1.0?°C and precipitation by 9?mm?yr?1. As such, our results suggest that carbon expenditures to support nitrogen-acquiring microbial symbionts have critical consequences for Earth's climate, and that carbon–climate models that omit these processes will overpredict the land carbon sink and underpredict climate change.Shi, W., Meng, F., Wang, X., Xu, L., Wu, C., Wang, R., 2018. The evaluation and prediction of source rocks in Huoshiling Formation of Gudian fault depression, south of Songliao Basin. Acta Petrolei Sinica 39, 1344-1354. of source rocks provides a basis for predicting oil and gas favorable target, playing an important role in drilling deployment of tight sandstone reservoirs. Organic geochemical characteristics of deep source rocks in Gudian fault depression are evaluated on a basis of organic matter abundance, organic matter type and organic matter maturity. According to the organic geochemical characteristics, Huoshiling Formation is classified as favorable source rocks. The analysis of hydrocarbon generation and evolution shows that source rocks of Huoshiling Formation reach the post-mature phase and primarily produce methane gas. Based on analyzing the single-well thermal evolution history of Well Lingshen1, it is reflected that source rocks in Huoshiling Formation are effective source rocks, and also the important source of natural gas in Gudian fault depression. By comparing the advantages and disadvantages of source rock formation identified by single-use 3D seismic data, seismic attributes and wave impedance inversion methods, respectively, this study proposes that the superposed method of wave impedance and instantaneous phase is more accurate for identifying source rock formations. This method is used to finely explain and analyze the source rock layers in Gudian area, and predict the distribution range of source rocks in Huoshiling Formation.Shmuel, B., Abraham, L., 2018. Could solar radiation pressure explain ‘Oumuamua’s peculiar acceleration? The Astrophysical Journal Letters 868, Article L1.'Oumuamua (1I/2017 U1) is the first object of interstellar origin observed in the solar system. Recently, Micheli et al. reported that 'Oumuamua showed deviations from a Keplerian orbit at a high statistical significance. The observed trajectory is best explained by an excess radial acceleration Δa ∝ r ?2, where r is the distance of 'Oumuamua from the Sun. Such an acceleration is naturally expected for comets, driven by the evaporating material. However, recent observational and theoretical studies imply that 'Oumuamua is not an active comet. We explore the possibility that the excess acceleration results from solar radiation pressure. The required mass-to-area ratio is (m/A) ≈ 0.1 g cm?2. For a thin sheet this requires a thickness of ≈0.3–0.9 mm. We find that although extremely thin, such an object would survive interstellar travel over Galactic distances of ~5 kpc, withstanding collisions with gas and dust grains as well as stresses from rotation and tidal forces. We discuss the possible origins of such an object. Our general results apply to any light probes designed for interstellar travel.Shumilova, T.G., Isaenko, S.I., Ulyashev, V.V., Makeev, B.A., Rappenglück, M.A., Veligzhanin, A.A., Ernstson, K., 2018. Enigmatic glass-like carbon from the Alpine Foreland, southeast Germany: A natural carbonization process. Acta Geologica Sinica - English Edition 92, 2179-2200. carbonaceous matter, termed here chiemite, composed of more than 90% C from the Alpine Foreland at Lake Chiemsee in Bavaria, southeastern Germany has been investigated using optical and atomic force microscopy, X‐ray fluorescence spectroscopy, scanning and transmission electron microscopy, high‐resolution Raman spectroscopy, X‐ray diffraction and differential thermal analysis, as well as by δ13C and 14C radiocarbon isotopic data analysis. In the pumice‐like fragments, poorly ordered carbon matter co‐exists with high‐ordering monocrystalline α‐carbyne, and contains submicrometer‐sized inclusions of complex composition. Diamond and carbyne add to the peculiar mix of matter. The required very high temperatures and pressures for carbyne formation point to a shock event probably from the recently proposed Holocene Chiemgau meteorite impact. The carbon material is suggested to have largely formed from heavily shocked coal, vegetation like wood, and peat from the impact target area. The carbonization/coalification high PT process may be attributed to a strong shock that instantaneously caused the complete evaporation and loss of volatile matter and water, which nevertheless preserved the original cellular structure seen fossilized in many fragments. Relatively fresh wood encapsulated in the purported strongly shocked matter point to quenched carbon melt components possibly important for the discussion of survival of organic matter in meteorite impacts, implying an astrobiological relationship.Sim, M.S., Ogata, H., Lubitz, W., Adkins, J.F., Sessions, A.L., Orphan, V.J., McGlynn, S.E., 2019. Role of APS reductase in biogeochemical sulfur isotope fractionation. Nature Communications 10, Article 44. isotope fractionation resulting from microbial sulfate reduction (MSR) provides some of the earliest evidence of life, and secular variations in fractionation values reflect changes in biogeochemical cycles. Here we determine the sulfur isotope effect of the enzyme adenosine phosphosulfate reductase (Apr), which is present in all known organisms conducting MSR and catalyzes the first reductive step in the pathway and reinterpret the sedimentary sulfur isotope record over geological time. Small fractionations may be attributed to low sulfate concentrations and/or high respiration rates, whereas fractionations greater than that of Apr require a low chemical potential at that metabolic step. Since Archean sediments lack fractionation exceeding the Apr value of 20‰, they are indicative of sulfate reducers having had access to ample electron donors to drive their metabolisms. Large fractionations in post-Archean sediments are congruent with a decline of favorable electron donors as aerobic and other high potential metabolic competitors evolved.Simkus, D.N., Aponte, J.C., Hilts, R.W., Elsila, J.E., Herd, C.D.K., 2019. Compound-specific carbon isotope compositions of aldehydes and ketones in the Murchison meteorite. Meteoritics & Planetary Science 54, 142-156.‐specific carbon isotope analysis (δ13C) of meteoritic organic compounds can be used to elucidate the abiotic chemical reactions involved in their synthesis. The soluble organic content of the Murchison carbonaceous chondrite has been extensively investigated over the years, with a focus on the origins of amino acids and the potential role of Strecker‐cyanohydrin synthesis in the early solar system. Previous δ13C investigations have targeted α‐amino acid and α‐hydroxy acid Strecker products and reactant HCN; however, δ13C values for meteoritic aldehydes and ketones (Strecker precursors) have not yet been reported. As such, the distribution of aldehydes and ketones in the cosmos and their role in prebiotic reactions have not been fully investigated. Here, we have applied an optimized O‐(2,3,4,5,6‐pentafluorobenzyl)hydroxylamine (PFBHA) derivatization procedure to the extraction, identification, and δ13C analysis of carbonyl compounds in the Murchison meteorite. A suite of aldehydes and ketones, dominated by acetaldehyde, propionaldehyde, and acetone, were detected in the sample. δ13C values, ranging from ?10.0‰ to +66.4‰, were more 13C‐depleted than would be expected for aldehydes and ketones derived from the interstellar medium, based on interstellar 12C/13C ratios. These relatively 13C‐depleted values suggest that chemical processes taking place in asteroid parent bodies (e.g., oxidation of the IOM) may provide a secondary source of aldehydes and ketones in the solar system. Comparisons between δ13C compositions of meteoritic aldehydes and ketones and other organic compound classes were used to evaluate potential structural relationships and associated reactions, including Strecker synthesis and alteration‐driven chemical pathways.Singh, A., Srivastava, N., Dubey, S.K., 2019. Molecular characterization and kinetics of isoprene degrading bacteria. Bioresource Technology 278, 51-56., the highly reactive volatile organic compound, is used as monomer for the synthesis of several useful polymers. Its extensive production and usage leads to contamination of air. Once released, it alters the atmospheric chemistry by reacting with hydroxyl radicals (OH) and nitrogen oxides (NOx) to generate tropospheric ozone. Its prolonged exposure causes deleterious effects in human and plants. Therefore, its removal from the contaminated environment through biodegradation, provides a promising remedial solution. In the present study, isoprene utilizing bacteria namely, Pseudomonas sp., Arthrobacter sp., Bacillus sp. Sphingobacterium sp., Sphingobium sp., and Pantoea sp. were isolated and characterized from leaf surface of Madhuca latifolia and Tectona grandis, and also from soils under these plants. Their isoprene degrading capability and kinetics were assessed in batch mode. The isoprene degradation study indicated Pseudomonas sp. to be the most efficient isoprene degrader.Skog, K.M., Xiong, F., Kawashima, H., Doyle, E., Soto, R., Gentner, D.R., 2019. Compact, automated, inexpensive, and field-deployable vacuum-outlet gas chromatograph for trace-concentration gas-phase organic compounds. Analytical Chemistry 91, 1318-1327. identification and quantification of gas-phase organic compounds, such as volatile organic compounds (VOCs), frequently use gas chromatography (GC), which typically requires high-purity compressed gases. We have developed a new instrument for trace-concentration measurements of VOCs and intermediate-volatility compounds of up to 14 carbon atoms in a fully automated (computer-free), independent, low-cost, compact GC-based system for the quantitative analysis of complex mixtures without the need for compressed, high-purity gases or expensive detectors. Through adsorptive analyte preconcentration, vacuum GC, photoionization detectors, and need-based water-vapor control, we enable sensitive and selective measurements with picogram-level limits of detection (i.e., under 15 ppt in a 4 L sample for most compounds). We validate performance against a commercial pressurized GC, including resolving challenging isomers of similar volatility, such as ethylbenzene and m/p-xylene. We employ vacuum GC across the whole column with filtered air as a carrier gas, producing long-term system stability and performance over a wide range of analytes. Through theory and experiments, we present variations in analyte diffusivities in the mobile phase, analyte elution temperatures, optimal linear velocities, and separation-plate heights with vacuum GC in air at different pressures, and we optimize our instrument to exploit these differences. At 2–6 psia, the molecular diffusion coefficients are 6.4–2.1 times larger and the elution temperatures are 39–92 °C lower than with pressurized GC with helium (at 30 psig) depending on the molecular structure, and we find a wide range of optimal linear velocities (up to 60 cm s?1) that are faster with broader tolerances than with pressurized-N2 GC.Slyundina, M.S., Borisov, R.S., Zaikin, V.G., 2018. Novel reactive matrices for the analysis of alcohols by matrix-assisted laser desorption/ioization mass spectrometry. Journal of Analytical Chemistry 73, 1347-1352. possibility of using a number of aromatic and heteroaromatic carboxylic acids and their halogen anhydrides as reactive matrix compounds for the analysis of alcohols of different structures by matrix-assisted laser desorption/ionization (MALDI) mass spectrometry has been studied. It is shown that the acylation of alcohols with nicotinic and quinoline-6-carboxylic acid chlorides gives derivatives with high desorption/ionization efficiency under MALDI conditions, and that the free acids formed as a result of the hydrolysis of anhydrides act as matrix compounds. The proposed approach is tested on a number of aliphatic, alicyclic, and aromatic alcohols.Smirnov, M.B., Poludetkina, E.N., 2018. Assessment of bioproduction relevance in the photic layer anoxia conditions at the formation of dispersed organic matter of source rocks and oils by mass spectrometry data. Journal of Analytical Chemistry 73, 1364-1371. procedure is proposed for estimating the content of individual groups of compounds, anoxia markers, in the photic layer of the sedimentation basin and their total content in fractions of oils and dispersed organic matter. Appropriate variants of data presentation are analyzed. Based on the data on the common content of anoxia markers, a method has been proposed for answering the question of whether hydrogen sulfide contamination was permanent, covering the major part of the water column, or there was an episodic infection spread to a limited water layer. These data also allow the assessment of the role of organic matter formed under anoxic conditions in its total balance. A composition parameter is proposed that ensures the determination of the similarities in the conditions of organic matter transformation in different rocks.Smith, C.J., Forster, P.M., Allen, M., Fuglestvedt, J., Millar, R.J., Rogelj, J., Zickfeld, K., 2019. Current?fossil fuel infrastructure does not yet commit us to 1.5?°C warming. Nature Communications 10, 101. warming describes how much future warming can be expected from historical emissions due to inertia in the climate system. It is usually defined in terms of the level of warming above the present for an abrupt halt of emissions. Owing to socioeconomic constraints, this situation is unlikely, so we focus on the committed warming from present-day fossil fuel assets. Here we show that if carbon-intensive infrastructure is phased out at the end of its design lifetime from the end of 2018, there is a 64% chance that peak global mean temperature rise remains below 1.5?°C. Delaying mitigation until 2030 considerably reduces the likelihood that 1.5?°C would be attainable even if the rate of fossil fuel retirement was accelerated. Although the challenges laid out by the Paris Agreement are daunting, we indicate 1.5?°C remains possible and is attainable with ambitious and immediate emission reduction across all sectors.Soina, V.S., Mergelov, N.S., Kudinova, A.G., Lysak, L.V., Demkina, E.V., Vorobyova, E.A., Dolgikh, A.V., Shorkunov, I.G., 2018. Microbial communities of soils and soil-like bodies in extreme conditions of East Antarctica. Paleontological Journal 52, 1186-1195. of an integrated study of microbial communities in soils and soil-like bodies formed in the wet intermountain valleys of East Antarctic oases under moss-, lichen-, algae- or cyanobacteria-dominated associations are summarized. Colonization of soil horizons by microorganisms, microbial biomass, potential biological activity, high viability of soil microorganisms and their resistance to extreme environmental conditions are considered. Perspectives of microbiological studies addressed towards evaluation of the functional role of microorganisms in the formation of Antarctica soils are discussed.Solihat, N.N., Acter, T., Kim, D., Plante, A.F., Kim, S., 2019. Analyzing solid-phase natural organic matter using laser desorption ionization ultrahigh resolution mass spectrometry. Analytical Chemistry 90, 951-957. sample preparation procedures are required to analyze natural organic matter (NOM) in soil and sediment samples due to the mineral matrix. The preparation procedure not only requires a large amount of sample (typically more than 50 mg), but NOM extraction is frequently incomplete. In this study, 2–5 μg of solid NOM or 500 μg of unprocessed soil samples were fixed on a metal plate using double-sided adhesive tape and analyzed directly using laser desorption ionization (LDI) and ultrahigh resolution mass spectrometry (UHR-MS). Most of the peaks reported in previous LDI UHR-MS studies using NOM solutions were observed, and an additional ～2200 unique peaks were found by analyzing the fulvic acids direct solid phase. Differences in the molecular composition of NOM in solid samples were seen clearly with minimum sample preparation. Lignin- and tannin-type molecules were detected in both Elliott soil and topsoil from Kyungpook National University campus. The data presented in this study demonstrate a proof-of-principle that highly sensitive, direct, molecular level analysis of solid-phase NOM from unprocessed soil samples and minimum sample preparation is possible.Soliman, Y.S., Alansari, E.M.A., Sericano, J.L., Wade, T.L., 2019. Spatio-temporal distribution and sources identifications of polycyclic aromatic hydrocarbons and their alkyl homolog in surface sediments in the central Arabian Gulf. Science of The Total Environment 658, 787-797. quantitative analysis of 18 parents and their alkyl homologs was performed in sediment samples from the central Arabian Gulf (Gulf) around Qatar Peninsula in six sequential seasons, winter 2014 to spring 2015, at 21 locations with a water depth range of 1.5–60?m. PAHs distribution was patchy with higher concentrations found inside semi-enclosed coastal areas like harbors and bays. The mean PAHs concentration was 112?ng·g?1 dry weight with a range of 0.6 to 1560?ng·g?1 and a variability coefficient of 2.4. The PAHs mean concentration was highest in the winter by a factor of 5 compared to mean summer concentration. A significant seasonal variability in the concentrations of ∑PAHs is mainly attributed to variability in the concentrations of the low molecular weight PAHs fraction and the less alkylated PAHs. Alkylated-PAHs were the most dominant PAHs comprising about 50% of the ∑PAHs, and with about 6 times higher than the mean concentrations in the winter compared to the mean summer concentration. The LPAHs concentrations correlated negatively with temperature and ∑PAHs correlated positively with % clay. Principal component analysis was used to identify sources of PAHs. PAHs in the Gulf have mixed sources with an estimated 57% from petroleum and 43% from pyrogenic sources. Coastal water hydrodynamics and lateral transport processes affect the distribution and composition of PAHs in the central Gulf.Song, J., Huang, C., Gong, Y., 2019. Response of ostracods (Crustacea) to the Devonian F—F event: Evidence from the Yangdi and Nandong sections in Guangxi, South China. Global and Planetary Change 173, 109-120. study focuses on the Late Devonian ostracods and their responses to the F—F (Frasnian-Famennian) event based on abundant materials collected from the Yangdi and Nandong sections in South China. More than half (53%) of the benthic ostracod species disappeared at the F—F boundary in the Yangdi section of slope facies, whereas most benthic ostracod species survived the F—F crisis in the Nandong section of basinal facies, with the extinction of some pelagic entomozooidea. In view of a higher extinction rate (more than 65%) of ostracod species in the shallow-water Xikuangshan section, we deduce that ostracods in varied environments responded to the F—F event differently. Namely, from the carbonate platform, slope, to basinal settings, the extinction rate of benthic ostracods at the F—F transition decreased with increasing water depth. Nevertheless, the F—F event caused substantial loss among pelagic entomozooidea lineages. The extinction pattern of benthic and pelagic ostracods in F—F event in South China is similar to the situation in Europe. But the extinction rates of benthic ostracods in shallow water and slope in Europe seems to be higher than that in the same situation in South China. The abundance and diversity of ostracods decreased and some species even disappeared in anoxic environments across the F—F boundary in South China, when there were rapid changes in the palaeotemperature of surface sea water.Song, L., Martin, K., Carr, T.R., Ghahfarokhi, P.K., 2019. Porosity and storage capacity of Middle Devonian shale: A function of thermal maturity, total organic carbon, and clay content. Fuel 241, 1036-1044. and pore size distribution (PSD) are critical reservoir parameters. Pore surface area, pore volume, PSD, and porosity were measured using subcritical nitrogen (N2) adsorption, and helium porosimetry. A suite of 17 samples were collected from 4 wells in Pennsylvania and West Virginia to analyze the evolution of porosity with increasing thermal maturity in Middle Devonian shales of the Appalachian Basin. The thermal maturity of the tested samples covers a wide range in the hydrocarbon generation sequence from wet gas/condensate zone (vitrinite reflectance (Ro)?=?1.16%) to post-mature zone (Ro?=?2.79%). Shale samples from the Marcellus Shale and Mahantango Formation used in this study have total organic carbon contents from 0.41 to 7.88?wt%. Results indicate that total organic carbon (TOC) has the strongest effect on porosity and pore structure. The presence of organic matter in shale strongly enhances the storage capacity by increasing the specific surface area and pore volume, which represents sorption storage capacity and free-gas storage capacity. Differences in porosity and pore structure have a complex relationship to thermal maturity, micro texture, mineralogy, clay content, and TOC.Song, X., Lü, X., Shen, Y., Guo, S., 2019. Hydrocarbon migration and accumulation history in deep reservoirs: a case study of Mesozoic sandstone gas reservoirs in the Kelasu-Yiqikelike structural belt of the Kuqa Depression, Tarim Basin. Geosciences Journal 23, 69-86. deep oil and gas reservoirs have recently been discovered in the Kelasu-Yiqikelike structural belt of the Kuqa Depression in the northern Tarim Basin, north-western China. The sources and accumulation processes of the oil and gas are determined in this study through a series of biomarker geochemical parameter analyses and fluid inclusion analyses, respectively. The geochemical parameters show that the oil of the Kela 2 gas field originated from the Triassic Huangshanjie (T3h) Formation lacustrine source rock and that the oil of the Jurassic reservoirs in the Dibei gas field was sourced from Jurassic coal measures, with some contribution from the T3h source rock. Furthermore, the gas in the Kela 2, Keshen and Dibei gas fields was derived from the Jurassic coal measures. Based on petrographic and fluid inclusion analyses, combined with a reconstruction of the reservoir burial history, timing estimates and charge models of the hydrocarbon accumulation have been obtained. Two stages of oil charging and one stage of gas charging were identified in the Kela 2 gas field. The two stages of oil charging occurred in the middle–late Miocene and in the early Pliocene. The gas charge occurred in the middle–late Pliocene. Additionally, one stage of gas charging occurred in the Keshen gas field in the late Pliocene to Quaternary. In contrast, two hydrocarbon charging stages were identified in the Dibei gas reservoirs, with the first occurring in the early Miocene and the second occurring in the Pliocene.Soru, S., Malavasi, V., Caboni, P., Concas, A., Cao, G., 2019. Behavior of the extremophile green alga Coccomyxa melkonianii SCCA 048 in terms of lipids production and morphology at different pH values. Extremophiles 23, 79-89. extremophile green alga Coccomyxa melkonianii SCCA 048 was investigated to evaluate its ability to grow in culture media with different pH. Specifically, Coccomyxa melkonianii was sampled in the Rio Irvi river (Sardinia, Italy) which is severely polluted by heavy metals as a result of abandoned mining activities. In this study, the strain was cultivated in growth media where the pH was kept fixed at the values of 4.0, 6.8 and 8.0, respectively. During the investigation, a significant phenotypic plasticity of this strain was observed. The strain grew well in the pH range 4.0–8.0, while the optimal value for its growth was 6.8. Furthermore, maximum lipid contents of about 24 and 22 %wt were achieved at the end of cultivation when using pH 4.0 and 8.0, respectively. Finally, the analysis of fatty acid methyl esters (FAMEs) highlights the presence of suitable amounts of compounds which can be profitably exploited in the food, nutraceutical, and cosmetic industry. This aspect, coupled with the possibility of cultivating Coccomyxa melkonianii under extreme pH conditions in economic open ponds, makes this strain an interesting candidate for several biotechnological applications.Steinthorsdottir, M., Vajda, V., Pole, M., 2019. Significant transient pCO2 perturbation at the New Zealand Oligocene-Miocene transition recorded by fossil plant stomata. Palaeogeography, Palaeoclimatology, Palaeoecology 515, 152-161. reorganisation of Earth's climate system from the Oligocene to the Miocene was influenced by complex interactions between Tethyan tectonics, orbital parameters, oceanographic changes, and carbon cycle feedbacks, with climate modelling indicating that pCO2 was an important factor. Oscillating episodes of climate change during the Oligocene–Miocene transition (OMT) have however been difficult to reconcile with existing pCO2 records. Here we present a new pCO2 record from the OMT into the early Miocene, reconstructed using the stomatal proxy method with a database of fossil Lauraceae leaves from New Zealand. The leaf database derives from three relatively well-dated sites located in the South Island of New Zealand; Foulden Maar, Mataura River and Grey Lake. Atmospheric pCO2 values were obtained based on four separate calibrations with three nearest living equivalents, using the stomatal ratio method as well as transfer functions. Our results, based on the mean values of each of the four calibrations, indicate pCO2 ranging ~582–732?ppm (average 650?ppm) at the OMT, falling precipitously to mean values of ~430–538?ppm (average 492?ppm) for the earliest Miocene and ~454–542?ppm (average 502?ppm) in the early Miocene. The much higher values of pCO2 at the OMT indicate that pCO played an important role in climate dynamics during this time, potentially including the abrupt termination of glaciations.Stephan, T., Kroner, U.W.E., Romer, R.L., 2019. The pre-orogenic detrital zircon record of the Peri-Gondwanan crust. Geological Magazine 156, 281-307. present a statistical approach to data mining and quantitatively evaluating detrital age spectra for sedimentary provenance analyses and palaeogeographic reconstructions. Multidimensional scaling coupled with density-based clustering allows the objective identification of provenance end-member populations and sedimentary mixing processes for a composite crust. We compiled 58 601 detrital zircon U–Pb ages from 770 Precambrian to Lower Palaeozoic shelf sedimentary rocks from 160 publications and applied statistical provenance analysis for the Peri-Gondwanan crust north of Africa and the adjacent areas. We have filtered the dataset to reduce the age spectra to the provenance signal, and compared the signal with age patterns of potential source regions. In terms of provenance, our results reveal three distinct areas, namely the Avalonian, West African and East African–Arabian zircon provinces. Except for the Rheic Ocean separating the Avalonian Zircon Province from Gondwana, the statistical analysis provides no evidence for the existence of additional oceanic lithosphere. This implies a vast and contiguous Peri-Gondwanan shelf south of the Rheic Ocean that is supplied by two contrasting super-fan systems, reflected in the zircon provinces of West Africa and East Africa–Arabia.Steven, R.T., Shaw, M., Dexter, A., Murta, T., Green, F.M., Robinson, K.N., Gilmore, I.S., Takats, Z., Bunch, J., 2019. Construction and testing of an atmospheric-pressure transmission-mode matrix assisted laser desorption ionisation mass spectrometry imaging ion source with plasma ionisation enhancement. Analytica Chimica Acta 1051, 110-119. assisted laser desorption ionisation mass spectrometry (MALDI-MS) at atmospheric pressure (AP) is, with a few notable exceptions, overshadowed by its vacuum based forms and AP transmission mode (TM) MALDI-MS lacks the up-take its potential benefits might suggest. The reasons for this are not fully understood and it is clear further development is required to realise the flexibility and power of this ionisation method and geometry. Here we report the build of a new AP-TM-MALDI-MSI ion source with plasma ionisation enhancement. This novel ion source is used to analyse a selection of increasingly complex systems from molecular standards to murine brain tissue sections. Significant enhancement of detected ion intensity is observed in both positive and negative ion mode in all systems, with up to 2000 fold increases observed for a range of tissue endogenous species. The substantial improvements conferred by the plasma enhancement are then employed to demonstrate the acquisition of proof of concept tissue images, with high quality spectra obtained down to 10?×?10?μm pixel size.Stevens, A.H., Childers, D., Fox-Powell, M., Nicholson, N., Jhoti, E., Cockell, C.S., 2018. Growth, viability, and death of planktonic and biofilm Sphingomonas desiccabilis in simulated martian brines. Astrobiology 19, 87-98. solutions on Mars are theorized to contain very different ion compositions than those on Earth. To determine the effect of such solutions on typical environmental micro-organisms, which could be released from robotic spacecraft or human exploration activity, we investigated the resistance of Sphingomonas desiccabilis to brines that simulate the composition of martian aqueous environments. S. desiccabilis is a desiccation-resistant, biofilm-forming microbe found in desert crusts. The viability of cells in both planktonic and biofilm forms was measured after exposure to simulated martian brines. Planktonic cells showed a loss of viability over the course of several hours in almost all of the seven brines tested. Biofilms conferred greater resistance to all the brines, including those with low water activity and pH, but even cells in biofilms showed a complete loss of viability in <6?h in the harsher brines and in <2 days in the less harsh brines. One brine, however, allowed the microbes to maintain viability over several days, despite having a water activity and pH lower and ionic strength higher than brines that reduced viability over the same timescales, suggesting important ion-specific effects. These data show that biofilm-forming cells have a greater capacity to resist martian aqueous extremes, but that evaporative or deliquescent brines are likely to be destructive to many organisms over relatively short timescales, with implications for the habitability of Mars and for micro-organisms dispersed by robotic or human explorers.Straume, E.O., Morales, R.E.M., Sum, A.K., 2019. Perspectives on gas hydrates cold flow technology. Energy & Fuels 33, 1-15. hydrates cold flow can be defined as flow of non-adhesive and non-cohesive hydrate particles dispersed in the production fluids flowlines. Implementation of cold flow related hydrate management strategies might significantly reduce the costs of oil and gas field development and production by removing or reducing the need for injection of chemicals, insulation, and heating. Several research groups have performed experiments focusing on different methods of producing hydrate dispersion. Hydrate particles can be seeded into the production fluids at hydrate stable conditions to initiate controlled growth of hydrates as the dispersion is cooled to temperature conditions in production systems. Alternatively, the water droplet size in water in oil dispersions can be reduced by utilizing static mixers, high velocity, or small concentrations of chemicals, which might facilitate readily conversion of the small water droplets into hydrate particles. One researcher has proposed separating liquid phases from gas and supercooling of liquid phases before mixing the phases for hydrate formation. Use of anti-agglomerants combined with reducing viscosity by increasing water content has been proposed by other researchers. Cold flow as a component of a natural gas dehydration process is described in a patent application but has not been experimentally tested. Laboratory-scale flow loop experiments indicate that cold flow works well for low to medium gas/oil ratios and up to 20% water cut for both oil and condensate dominated systems. Experiments with crude oils containing wax show that cold flow could significantly reduce or eliminate wax deposition on pipeline walls. A field trial of the cold flow method in a once-through flowline focused on reducing droplet size, resulting in hydrate deposition. This review discusses utilized methods and published results on cold flow from various research groups in light of known mechanisms for hydrate formation. Some suggestions are also given with focus for future research in order to develop, validate, and implement cold flow as a reliable technology for hydrate management method in the production of hydrocarbon fluids.Su, S., Jiang, Z., Shan, X., Ning, C., Zhu, Y., Wang, X., Li, Z., Zhu, R., 2019. Effect of lithofacies on shale reservoir and hydrocarbon bearing capacity in the Shahejie Formation, Zhanhua Sag, eastern China. Journal of Petroleum Science and Engineering 174, 1303-1308. using microscope, nuclear magnetic resonance (NMR), hydrocarbon generation and expulsion and nitrogen adsorption, reservoir properties and oil-gas bearing capacity of different shale lithofacies were examined with the continental shale of Zhanhua Sag in the Jiyang Depression of the Bohai Bay Basin as the examples. The results showed that the organic-rich laminar lithofacies have the best oil and gas bearing properties, while the organic-rich layer lithofacies take second place. The laminar lithofacies mainly developed mesopores and macropores, even microcracks, and the porosity connectivity is better than that of the layer lithofacies. The micropores and mesopores are mainly developed in the layer lithofacies, so the reservoir space is small. Therefore, the lithofacies with laminar not only increases the storage space of reservoir but also can improve the mobility of oil and gas. By the actual oil production comparison of different lithofacies, the hydrocarbon generation quantity of the organic-rich lithofacies is 336.68t, otherwise, the organic-contain lithofacies only 40.49t. Therefore, the organic-rich laminar lithofacies have the best oil production effect and can be used as a favorable target for oil and gas exploration in shale.Suarez-Dominguez, E.J., Xu, B., Perez-Sanchez, J.F., Palacio-Perez, A., Izquierdo-Kulich, E., 2018. Stochastic modeling of asphaltenes deposition and prediction of its influence on friction pressure drop. Petroleum Science and Technology 36, 1812-1819. dealing with heavy and extra-heavy crude oils, petroleum industry faces the deposition and incrustation of solids on pipelines walls during fluids transportation. Such a deposition phenomenon is supposed to be caused by asphaltenes aggregation. In this work, is presented a stochastic model that predicts the behavior of friction pressure drop with respect to asphaltenes concentration and the deposition and detaching velocities through the principles of fractal geometry and differential fractional calculus. Results show that at higher values of asphaltenes total concentration and deposition velocity, the friction pressure losses are also increased, which is an expected behavior because of the thickness and morphology of the asphaltenes deposited layer.Suarez, E.M., Lepkova, K., Kinsella, B., Machuca, L.L., 2019. Aggressive corrosion of steel by a thermophilic microbial consortium in the presence and absence of sand. International Biodeterioration & Biodegradation 137, 137-146. influenced corrosion of carbon steel by a thermophilic microbial consortium was investigated in the presence and absence of sand using surface analysis techniques and 16S rRNA gene sequencing. The activity of the consortium, involving methanogens, fermenting and sulphidogenic microorganisms, significantly increased average and localised corrosion regardless of the presence of sand deposit. Microbial metabolisms and syntrophic relationships of the consortium species contributing to accelerated corrosion were discussed. Electrochemical reactions are proposed based on the layers of corrosion products deposited on the metal surface. Differences in the microbial community composition and corrosion products stratification were identified between steel samples covered and uncovered with sand. This work is closely related to industrial applications highlighting the importance of conducting tests for under deposit corrosion incorporating microbial consortia isolated from the field environment. Otherwise, the severity of localised corrosion could be severely underestimated.Sugisaki, K., Nakazawa, S., Toyota, K., Sato, K., Shiomi, D., Takui, T., 2018. Quantum chemistry on quantum computers: A method for preparation of multiconfigurational wave functions on quantum computers without performing post-Hartree–Fock calculations. ACS Central Science 5, 167-175. full configuration interaction (full-CI) method is capable of providing the numerically best wave functions and energies of atoms and molecules within basis sets being used, although it is intractable for classical computers. Quantum computers can perform full-CI calculations in polynomial time against the system size by adopting a quantum phase estimation algorithm (QPEA). In the QPEA, the preparation of initial guess wave functions having sufficiently large overlap with the exact wave function is recommended. The Hartree–Fock (HF) wave function is a good initial guess only for closed shell singlet molecules and high-spin molecules carrying no spin-β unpaired electrons, around their equilibrium geometry, and thus, the construction of multiconfigurational wave functions without performing post-HF calculations on classical computers is highly desired for applying the method to a wide variety of chemistries and physics. In this work, we propose a method to construct multiconfigurational initial guess wave functions suitable for QPEA-based full-CI calculations on quantum computers, by utilizing diradical characters computed from spin-projected UHF wave functions. The proposed approach drastically improves the wave function overlap, particularly in molecules with intermediate diradical characters.Sulej, T., Nied?wiedzki, G., 2019. An elephant-sized Late Triassic synapsid with erect limbs. Science 363, 78.: Here, we describe the dicynodont Lisowicia bojani, from the Late Triassic of Poland, a gigantic synapsid with seemingly upright subcursorial limbs that reached an estimated length of more than 4.5 meters, height of 2.6 meters, and body mass of 9 tons. Lisowicia is the youngest undisputed dicynodont and the largest nondinosaurian terrestrial tetrapod from the Triassic. The lack of lines of arrested growth and the highly remodeled cortex of its limb bones suggest permanently rapid growth and recalls that of dinosaurs and mammals. The discovery of Lisowicia overturns the established picture of the Triassic megaherbivore radiation as a phenomenon restricted to dinosaurs and shows that stem-group mammals were capable of reaching body sizes that were not attained again in mammalian evolution until the latest Eocene.Editors' Summary, A proto-mammalian giant: Early terrestrial amniotes evolved into two groups: the sauropsids, which led to the bird and dinosaur lineages, and the synapsids, which led to mammals. Synapsids were diverse during the Permian but were greatly reduced after the end-Permian extinction (about 252 million years ago). The few groups that survived into the Triassic were mostly small and retained a sprawling gait. Sulej and Nied?wiedzki, however, describe a dicynodont from the Late Triassic of Poland that is as large as some coexisting dinosaurs and appears to have had an erect gait—like modern mammals. Thus, megaherbivores in the Triassic were not only dinosaurs.Sun, C., Liu, H., Ge, J., Zhang, Y., Han, B., Qin, M., 2019. Changes of functional groups and gas species during oil shale pyrolysis with addition of pyrite. Energy Sources, Part A: Recovery, Utilization, and Environmental Effects 41, 1242-1252. shale is a potential substitute fossil fuel for petroleum and gas and has attracted much attention in recent years. This study investigated the pyrolysis characteristics of LongKou oil shale in a horizontal pipe furnace, and the gas production and functional groups in coke when different amounts of pyrite were added. The results showed that the organic matrix was decomposed completely in the optimal conditions (a temperature of 500°C, a gas speed of 300 mL/min and a resident time of 40 min). For aromatic hydrocarbon, substitution can be promoted in the direction of H-decrease by the presence of pyrite. For aliphatics, pyrite will inhibit the condensation of macromolecules causing an increase of aliphatic chain length. For O-containing groups, carboxyl was consumed completely and the ratio of C = O to aromatic carbon was decreased. And for gas products, pyrite can promote the generation of CO2, CO and CH4 on the whole. But it is worth mentioning that when the content of pyrite is suitable (2%), generation of all gases especially CO and CH4 is promoted significantly. Considering the pyrite is an important part in untreated oil shale, the results obtained in this research may be able to provide some useful information for desulfurization and gas production in oil shale retorting.Sun, G., Lu, H., 2019. Recent advances in microfluidic techniques for systems biology. Analytical Chemistry 90, 315-329. hydraulic stimulation, waste fluid returns to the surface due to the high pressures in the well. This fluid, referred to as flowback water, is wastewater that contains high levels of dissolved solids, salts, and fracturing chemicals. When the flowback finishes, fluid that is within the oil or gas-producing formation can be recovered, which is called produced water. This produced water has high concentrations of salt and can contain harmful levels of metals and radioactivity.(4,6) When they return to the surface, these waste streams must be disposed of, treated, and/or reused.The environmental implications of UOG remain a complex and polarizing topic.(8) Surface water,(9?11) groundwater,(12?20) soil,(21?24) and air(25?31) are potentially subject to contamination from surface spills, transport of fluids through microscale annular fissures in UOG gas wells, gas emissions, and the physical mobilization of ions from scale/rust formations.(9,20,32) Understanding the causes of potential contamination is therefore important to develop responsible energy extraction and environmental stewardship practices. The development of analytical techniques to help provide this understanding is vital. This is a field that is still growing, as some factors still limit the research performed. Groundwater and produced water samples are often very difficult to obtain, and funding for this type of research is currently inadequate. The majority of groundwater samples that have been analyzed as part of most published monitoring studies have been obtained mainly from residential wells, which requires the participation of landowners/well owners. The variability in the willingness to participate, based on the different views and beliefs of those approached to obtain samples, is a confounding factor that may be perceived as experimental bias. Additionally, not all densely populated areas experiencing UOG have water wells, which hinders the ability to perform high-resolution mapping of those areas.The economics of this research also vary depending on who is performing it (academic, commercial, or governmental laboratories). The lack of funding in this field slows down the development of high-resolution techniques for the multiparametric determination of hydraulic fracturing compounds. Furthermore, the lack of communication by the industry as a whole (with some exceptions) also limits the development of environmental impact studies. A better line of communication between academic and private sector partners could provide insight on sampling times in order to align analyses with different aspects of the UOG operations process and what chemicals should be avoided and replaced. Overall, these are all difficulties that limit the research performed in this field and its advancement.Sun, T., Wang, D., Tang, Y., Xing, X., Zhuang, J., Cheng, J., Du, Z., 2019. Fabric-phase sorptive extraction coupled with ion mobility spectrometry for on-site rapid detection of PAHs in aquatic environment. Talanta 195, 109-116. contamination of water is a high risk to human health, so there is an urgent need to rapidly detect water pollution in the field. Ion mobility spectrometry (IMS) is suitable for on-site analysis with the merit of rapid analysis and compact size. In this study, we developed a new method which coupled fabric phase sorptive extraction (FPSE) with IMS for rapid detection of polycyclic aromatic hydrocarbons (PAHs) in water present in the field. Polydimethylsiloxane (PDMS) was coated on the glass fiber cloth through a sol-gel reaction. After extracting the PAHs in water, the fabric coated PDMS could be directly put into the inlet of IMS instrument for thermal desorption. The PAHs were analyzed by the IMS instrument operated in the positive ion mode with a corona discharge (CD) ionization source. The primary parameters affecting extraction efficiency such as extraction time, extraction temperature, and ionic strength were investigated and optimized by using phenanthrene (Phe), benzo[a]anthracene (BaA) and benzo[a]pyrene (BaP) as model compounds. Under the optimal conditions, the FPSE-IMS detection limits were 5?ng?ml?1,8?ng?ml?1 and 10?ng?ml?1 respectively. Satisfactory recoveries were obtained in the range from 80.5% to 100.5% by testing the spiked real water samples and validated by the standard method（HJ487-2009）. Based on the results, the method of FPSE-IMS could be feasibly applied for monitoring the water quality on-site and providing early warning in the field.Sun, Y., Yin, Q., Crucifix, M., Clemens, S.C., Araya-Melo, P., Liu, W., Qiang, X., Liu, Q., Zhao, H., Liang, L., Chen, H., Li, Y., Zhang, L., Dong, G., Li, M., Zhou, W., Berger, A., An, Z., 2019. Diverse manifestations of the mid-Pleistocene climate transition. Nature Communications 10, Article 352. mid-Pleistocene transition (MPT) is widely recognized as a shift in paleoclimatic periodicity from 41- to 100-kyr cycles, which largely reflects integrated changes in global ice volume, sea level, and ocean temperature from the marine realm. However, much less is known about monsoon-induced terrestrial vegetation change across the MPT. Here, on the basis of a 1.7-million-year δ13C record of loess carbonates from the Chinese Loess Plateau, we document a unique MPT reflecting terrestrial vegetation changes from a dominant 23-kyr periodicity before 1.2?Ma to combined 100, 41, and 23-kyr cycles after 0.7?Ma, very different from the conventional MPT characteristics. Model simulations further reveal that the MPT transition likely reflects decreased sensitivity of monsoonal hydroclimate to insolation forcing as the Northern Hemisphere became increasingly glaciated through the MPT. Our proxy-model comparison suggests varied responses of temperature and precipitation to astronomical forcing under different ice/CO2 boundary conditions, which greatly improves our understanding of monsoon variability and dynamics from the natural past to the anthropogenic future.Sun, Y.D., Richoz, S., Krystyn, L., Zhang, Z.T., Joachimski, M.M., 2019. Perturbations in the carbon cycle during the Carnian Humid Episode: carbonate carbon isotope records from southwestern China and northern Oman. Journal of the Geological Society 176, 167. Carnian Humid Episode is an interval of prominent climatic changes in the Late Triassic. We studied the carbon isotope (δ13C) geochemistry of carbonates from sections in southwestern China and northern Oman. δ13C records from the Yongyue section (western Guizhou, South China) show a progressive positive shift from 1.4 to 2.8‰ in the early to middle Julian 1 substage. This positive trend is followed by a swift negative shift of c. 4.2‰ from 2.8 to ?1.4‰ in the Julian 2 substage. δ13C from the Wadi Mayhah section (northern Oman) shows a positive shift from 2.2 to 2.8‰ in the Julian 1 substage, followed by a negative shift of c. 3.2‰ from 2.8 to ?0.3‰ in the Julian 2 substage. The δ13C records from the two study sections generally correlate well with each other as well as with published records, pointing to a considerable input of isotopically light carbon starting in the late Julian 1 substage. Such a large amount of light carbon probably derived from direct degassing and the sediment–sill contact metamorphism of the Panthalassan Wrangellia Large Igneous Province and contemporary Tethyan volcanism. The voluminous volcanogenic greenhouse gases probably contributed to the warming pulse in the middle Carnian. Thus the dry–wet climatic transition during the Carnian Humid Episode is best interpreted as a warm climate-driven intensification of the activities of the atmospheric circulation and hydrological cycle.Swales, J.G., Hamm, G., Clench, M.R., Goodwin, R.J.A., 2019. Mass spectrometry imaging and its application in pharmaceutical research and development: A concise review. International Journal of Mass Spectrometry 437, 99-112. the biodistribution, metabolism and accumulation of drugs in the body is a fundamental of pharmaceutical research and development. Mass Spectrometry imaging (MSI) has been proven to be a powerful tool to image the unlabelled spatial distribution of exogenous drugs and endogenous metabolites from the surface of tissue sections or small clinical biopsies, aiding the delivery of safe and effective medicines to the market and ultimately benefiting patients. Here we review the current advancements in MSI sample preparation, qualitative and quantitative MSI methodology and drug discovery and development applications. MSI is shown to be supporting R&D from early target identification through to the clinic. In conclusion, we discuss future directions of the technology and the hurdles that need addressing to strengthen its status in multimodal imaging.Takahashi, S., Nakada, R., Watanabe, Y., Takahashi, Y., 2019. Iron-depleted pelagic water at the end-Permian mass extinction inferred from chemical species of iron and molybdenum in deep-sea sedimentary rocks. Palaeogeography, Palaeoclimatology, Palaeoecology 516, 384-399. study determined chemical species of iron (Fe) and molybdenum (Mo) in a pelagic deep-sea Permian–Triassic boundary section, that records redox variations across the severe mass extinction event. We applied X-ray diffraction (XRD) and extended X-ray absorption fine structure (EXAFS) at the Fe K-edge and X-ray absorption near-edge structure (XANES) at the Mo K-edge to silicic sedimentary rock samples for analysis of the studied section. According to the EXAFS and XRD analyses, pyrite was the dominant Fe-bearing mineral in most samples, whereas ferric minerals such as hematite were absent throughout the Permian–Triassic transition. This result supports those of previous studies of other deep-sea Japanese Permian-Triassic boundary (PTB) sections. The Fe in pyrite mineral quantified by EXAFS spectra displayed synchronous variation with sulphide-sulphur (Ssulphide) but with total organic carbon content, which revealed the Fe-limited conditions for pyrite formation in the pelagic Panthalassa region. The XANES analysis indicated the presence of tetrahedral and octahedral configurations of Mo bonded to oxygen (O) and sulphur (S), which were referred to as MoO42?, MoO3 (as a possible alternative reference material of Mo in organic ligands), MoO2 and MoS2. The MoS2 species dominated in the end-Permian horizons, coinciding with high abundances of total Mo, which suggests a sulphidic depositional environment. The MoS2 and MoO3 species were the main contributors to these high Mo abundances in the end-Permian strata. The presence of the molybdenite (MoS2) species in the studied section indicates that the samples were subjected to alteration under high temperatures, with sufficiently sulphidic and limited reactive Fe availability conditions for MoS2 formation during late diagenesis. The Fe in pyrite decreased across the mass extinction boundary, which coincided with the highest total Mo amount with the MoS2 and MoO3 species. These trends reflected a decrease in reactive Fe in the sediments and contemporaneous seawaters under sulphidic conditions. The low reactive Fe condition could be due to massive pyrite formation under prolonged sulphidic water conditions in the pelagic and ambient continental margin regions in the end-Permian.Tang, F., Taylor, R.J.M., Einsle, J.F., Borlina, C.S., Fu, R.R., Weiss, B.P., Williams, H.M., Williams, W., Nagy, L., Midgley, P.A., Lima, E.A., Bell, E.A., Harrison, T.M., Alexander, E.W., Harrison, R.J., 2019. Secondary magnetite in ancient zircon precludes analysis of a Hadean geodynamo. Proceedings of the National Academy of Sciences 116, 407-412. Significance: The Earth’s geodynamo is critical in protecting our atmosphere, and thus plays an important role in the habitability of our planet. As such, the Earth’s magnetic field has likely played a crucial role in the emergence of life around 4 billion years ago during the Hadean–Archean Eons. However, we know little about the behavior of the geodynamo during this critical period. Recent efforts have focused on the magnetic signals harbored by Jack Hills zircon crystals, the oldest terrestrial material. Here we show the magnetic carriers in such grains. Our results demonstrate that although ancient zircon grains may contain ideal magnetic recorders, they do not record the magnetic field strength at the time of zircon growth.Abstract: Zircon crystals from the Jack Hills, Western Australia, are one of the few surviving mineralogical records of Earth’s first 500 million years and have been proposed to contain a paleomagnetic record of the Hadean geodynamo. A prerequisite for the preservation of Hadean magnetization is the presence of primary magnetic inclusions within pristine igneous zircon. To date no images of the magnetic recorders within ancient zircon have been presented. Here we use high-resolution transmission electron microscopy to demonstrate that all observed inclusions are secondary features formed via two distinct mechanisms. Magnetite is produced via a pipe-diffusion mechanism whereby iron diffuses into radiation-damaged zircon along the cores of dislocations and is precipitated inside nanopores and also during low-temperature recrystallization of radiation-damaged zircon in the presence of an aqueous fluid. Although these magnetites can be recognized as secondary using transmission electron microscopy, they otherwise occur in regions that are indistinguishable from pristine igneous zircon and carry remanent magnetization that postdates the crystallization age by at least several hundred million years. Without microscopic evidence ruling out secondary magnetite, the paleomagnetic case for a Hadean–Eoarchean geodynamo cannot yet been made.Tang, Y.-J., Li, M.-J., Fang, R.-H., Zhang, B.-S., Yang, Z., He, D.-X., Li, M.-R., 2019. Geochemistry and origin of Ordovician oils in the Rewapu Block of the Halahatang Oilfield (NW China). Petroleum Science 16, 1-13. oils in the Rewapu Block of the Halahatang Oilfield in the Tarim Basin (northwestern China) were geochemically analyzed by gas chromatography–mass spectrometry to investigate their origin and possible secondary alteration. The physical properties and chemical compositions of these Ordovician oils vary greatly, ranging from light to extremely heavy oils. All these oils belong to one single population and were derived from same source kitchen/bed. The differences in their chemical compositions and physical properties mainly result from secondary alteration of oils that were charged during the early phase of trap formation. The thickness of Upper Ordovician and Silurian caprocks of oil reservoirs in the Rewapu Block is higher than that in the north part of the Halahatang region, and therefore, significant biodegradation process is prevented. Compared to heavy oils in the north part, the Rewapu oils are dominated by light oils with no 25-norhopanes and no GC–MS “hump” (UCM: unresolved complex mixture) on the chromatographic baselines. The heavy oils in Wells RP7 and RP101C were primarily influenced by water washing since apparent reduction of alkylated dibenzothiophenes was observed. The local geological background favored the water washing alteration. The reservoir geochemical study has practical application in hydrocarbon exploration and predicts the nature of oils in this oilfield.Tang, Y., Lemaitre, N., Castrillejo, M., Roca-Martí, M., Masqué, P., Stewart, G., 2019. The export flux of particulate organic carbon derived from 210Po∕210Pb disequilibria along the North Atlantic GEOTRACES GA01 transect: GEOVIDE cruise. Biogeosciences 16, 309-327. disequilibrium between 210Po activity and 210Pb activity in seawater samples was determined along the GEOTRACES GA01 transect in the North Atlantic during the GEOVIDE cruise (May–June 2014). A steady-state model was used to quantify vertical export of particulate 210Po. Vertical advection was incorporated into one version of the model using time-averaged vertical velocity, which had substantial variance. This resulted in large uncertainties for the 210Po export flux in this model, suggesting that those calculations of 210Po export fluxes should be used with great care. Despite the large uncertainties, there is no question that the deficits of 210Po in the Iberian Basin and at the Greenland Shelf have been strongly affected by vertical advection. Using the export flux of 210Po and the particulate organic carbon (POC) to 210Po ratio of total (>?1??m) particles, we determined the POC export fluxes along the transect. Both the magnitude and efficiency of the estimated POC export flux from the surface ocean varied spatially within our study region. Export fluxes of POC ranged from negligible to 10?mmol?C?m?2?d?1, with enhanced POC export in the Labrador Sea. The cruise track was characterized by overall low POC export relative to net primary production (export efficiency <?1?%–15?%), but relatively high export efficiencies were seen in the basins where diatoms dominated the phytoplankton community. The particularly low export efficiencies in the Iberian Basin, on the other hand, were explained by the dominance of smaller phytoplankton, such as cyanobacteria or coccolithophores. POC fluxes estimated from the 210Po∕210Pb and 234Th∕238U disequilibria agreed within a factor of 3 along the transect, with higher POC estimates generally derived from 234Th. The differences were attributed to integration timescales and the history of bloom events.Temerdashev, Z.A., Musorina, T.N., Kiseleva, N.V., Eletskii, B.D., Chervonnaya, T.A., 2018. Gas chromatography–mass spectrometry determination of polycyclic aromatic hydrocarbons in surface water. Journal of Analytical Chemistry 73, 1154-1161. current status and problems of the determination of polycyclic aromatic hydrocarbons (PAHs) in surface waters are discussed. Sixteen unsubstituted PAHs, which are priority pollutants of aquatic ecosystems, are selected as analytes. Gas chromatography–mass spectrometry (GC–MS) ensures the identification of the majority of pollutants using an integrated spectral library and their determation at a level below the maximum permissible concentration (MPC). The conditions for the simultaneous determination of 16?unsubstituted PAHs by GC–MS with detection in the selected ion monitoring mode are optimized. PAHs were extracted from a 1-L water sample by ultrasound-assisted liquid–liquid extraction. The main performance characteristics of the procedure were estimated. The lower limit of the analytical range was from 0.5?ng/L (benzo(a)pyrene) to 50 ng/L (naphthalene); the upper limit of the analytical range was 250 ng/L for all PAHs. The procedure was tested in model systems and real samples.Temerdashev, Z.A., Pavlenko, L.F., Korpakova, I.G., Ermakova, Y.S., 2018. Analytical aspects of the determination of the total concentration and differentiation of anthropogenic and biogenic hydrocarbons in aquatic ecosystems. Journal of Analytical Chemistry 73, 1137-1145. of determining the total concentration of anthropogenic and biogenic hydrocarbons in aquatic ecosystems are discussed. Hydrocarbons accumulating in water samples and bottom sediments are different in composition. Polycyclic aromatic hydrocarbons, resistant to degradation, are concentrated in bottom sediments; their amount in the aquatic environment is insignificant. It is shown that the level of oil pollution can be adequately assessed only taking into account the biogenic (natural) hydrocarbon background of water and bottom sediments of the investigated objects. A unified pattern for the analysis of water and bottom sediments for assessing the level of oil contamination of aquatic ecosystems taking into account the transformation of oil components and the origin of hydrocarbons of different genesis is proposed. A possibility of the differentiation of petroleum and biogenic hydrocarbons in aquatic ecosystems by the concentration of chlorophyll in them is substantiated.Thi Van Le, H., Yu, K., 2019. Long-term effect of crude oil and dispersant on denitrification and organic matter mineralization in a salt marsh sediment. Chemosphere 220, 582-589. 2010 BP oil spill has an unprecedented impact on coastal wetland ecosystem along the northern Gulf of Mexico. A two-dimensional analysis (dispersant concentration and duration of exposure) was conducted by pre-incubation of a salt marsh sediment under an open or closed condition. Denitrification activity was characterized by N2O production using an acetylene (C2H2) blockage technique, and organic matter (OM) mineralization by CO2 production. The results show that even trace amount of the dispersant could significantly inhibit the denitrification activity by 20% (p?<?0.05). However, the sediment was resilient to the oil/dispersant contamination, likely due to shift of its microbial communities, by recovering the denitrification activity within 46 days in the open incubation. Inhibitory effect of the oil/dispersant on denitrification persisted beyond 46 days in the closed incubation, and the recovery could take up to 137 days depending on the dispersant concentration. The dispersant continuously stimulated OM mineralization that lowered the sediment redox status. Mobilization of N in the sediment from the OM mineralization forms a positive feedback loop, leading to deterioration of the coastal ecosystem. The study concludes that minimum dispersant should be applied for oil spill remediation, and oil cleanup operations should avoid moving the oil/dispersant from surface into deeper layers of the sediment. Synergistic interactions between the crude oil and dispersant and their biodegradation products deserves future examinations.Thiruvenkadam, S., Izhar, S., Hiroyuki, Y., Harun, R., 2019. One-step microalgal biodiesel production from Chlorella pyrenoidosa using subcritical methanol extraction (SCM) technology. Biomass and Bioenergy 120, 265-272. this work, we propose a one-step subcritical methanol extraction (SCM) process for biodiesel production from Chlorella pyrenoidosa. Therefore, the present study attempts to establish and determine the optimum operating conditions for maximum biodiesel yield from SCM of C. pyrenoidosa. A statistical approach, i.e. response surface methodology is employed in this study. The effects of three operational factors: reaction temperature (140–220?°C), reaction time (1–15?min) and methanol to algae ratio (1–9?wt.%) were investigated using a central composite design. A maximum yield of crude biodiesel of 7.1?wt.% was obtained at 160?°C, 3?min reaction time and 7?wt.% methanol to algae ratio. The analysis of variance revealed that methanol to algae ratio is the most significant factor for maximizing biodiesel yield. Regression analysis showed a good fit of the experimental data to the second-order polynomial model. With no requirement of catalyst nor any pretreatment step, SCM process is economically feasible to scale up the commercial biodiesel production from algae.Tilley, M.A., Segura, A., Meadows, V., Hawley, S., Davenport, J., 2018. Modeling repeated M dwarf flaring at an Earth-like planet in the habitable zone: Atmospheric effects for an unmagnetized planet. Astrobiology 19, 64-86. the impact of active M dwarf stars on the atmospheric equilibrium and surface conditions of a habitable zone Earth-like planet is key to assessing M dwarf planet habitability. Previous modeling of the impact of electromagnetic (EM) radiation and protons from a single large flare on an Earth-like atmosphere indicated that significant and long-term reductions in ozone were possible, but the atmosphere recovered. However, these stars more realistically exhibit frequent flaring with a distribution of different total energies and cadences. Here, we use a coupled 1D photochemical and radiative-convective model to investigate the effects of repeated flaring on the photochemistry and surface UV of an Earth-like planet unprotected by an intrinsic magnetic field. As input, we use time-resolved flare spectra obtained for the dM3 star AD Leonis, combined with flare occurrence frequencies and total energies (typically 1030.5 to 1034 erg) from the 4-year Kepler light curve for the dM4 flare star GJ1243, with varied proton event impact frequency. Our model results show that repeated EM-only flares have little effect on the ozone column depth but that multiple proton events can rapidly destroy the ozone column. Combining the realistic flare and proton event frequencies with nominal CME/SEP geometries, we find the ozone column for an Earth-like planet can be depleted by 94% in 10 years, with a downward trend that makes recovery unlikely and suggests further destruction. For more extreme stellar inputs, O3 depletion allows a constant ～0.1–1 W m?2 of UVC at the planet's surface, which is likely detrimental to organic complexity. Our results suggest that active M dwarf hosts may comprehensively destroy ozone shields and subject the surface of magnetically unprotected Earth-like planets to long-term radiation that can damage complex organic structures. However, this does not preclude habitability, as a safe haven for life could still exist below an ocean orek, Y.J., Mok, J.K., Shin, H.D., Lee, B.D., Lee, M.H., DiChristina, T.J., 2019. Metal reduction and protein secretion genes required for iodate reduction by Shewanella oneidensis. Applied and Environmental Microbiology 85, Article e02115-18.: The metal-reducing gammaproteobacterium Shewanella oneidensis reduces iodate (IO3?) as an anaerobic terminal electron acceptor. Microbial IO3? electron transport pathways are postulated to terminate with nitrate (NO3?) reductase, which reduces IO3? as an alternative electron acceptor. Recent studies with S. oneidensis, however, have demonstrated that NO3? reductase is not involved in IO3? reduction. The main objective of the present study was to determine the metal reduction and protein secretion genes required for IO3? reduction by Shewanella oneidensis with lactate, formate, or H2 as the electron donor. With all electron donors, the type I and type V protein secretion mutants retained wild-type IO3? reduction activity, while the type II protein secretion mutant lacking the outer membrane secretin GspD was impaired in IO3? reduction. Deletion mutants lacking the cyclic AMP receptor protein (CRP), cytochrome maturation permease CcmB, and inner membrane-tethered c-type cytochrome CymA were impaired in IO3? reduction with all electron donors, while deletion mutants lacking c-type cytochrome MtrA and outer membrane β-barrel protein MtrB of the outer membrane MtrAB module were impaired in IO3? reduction with only lactate as an electron donor. With all electron donors, mutants lacking the c-type cytochromes OmcA and MtrC of the metal-reducing extracellular electron conduit MtrCAB retained wild-type IO3? reduction activity. These findings indicate that IO3? reduction by S. oneidensis involves electron donor-dependent metal reduction and protein secretion pathway components, including the outer membrane MtrAB module and type II protein secretion of an unidentified IO3? reductase to the S. oneidensis outer membrane.Importance: Microbial iodate (IO3?) reduction is a major component in the biogeochemical cycling of iodine and the bioremediation of iodine-contaminated environments; however, the molecular mechanism of microbial IO3? reduction is poorly understood. Results of the present study indicate that outer membrane (type II) protein secretion and metal reduction genes encoding the outer membrane MtrAB module of the extracellular electron conduit MtrCAB are required for IO3? reduction by S. oneidensis. On the other hand, the metal-reducing c-type cytochrome MtrC of the extracellular electron conduit is not required for IO3? reduction by S. oneidensis. These findings indicate that the IO3? electron transport pathway terminates with an as yet unidentified IO3? reductase that associates with the outer membrane MtrAB module to deliver electrons extracellularly to IO3?.Tornos, F., Oggerin, M., Rodriguez, N., Amils, R., Ríos, A.d.l., Sanz, J.L., Rojas, P., Velasco, F., Gómez, C., Escobar, J.M., Slack, J.F., 2018. Do microbes control the formation of giant copper deposits? Geology 47, 143-146. formation of secondary copper deposits, the source of more than half of the world’s production, is usually interpreted as abiogenic. In this study of the Las Cruces deposit (southwestern Spain), in situ hybridization and scanning electron microscopy analysis together with integrated genomic and bioinformatic studies on cultures provide compelling evidence that a microbial community controls the current formation of the secondary copper mineralization. The cementation zone of this deposit contains abundant microbial life dominated by sulfate-reducing bacteria that coexist with methanogens and with other prokaryotes having unknown roles. Fractures in the primary massive sulfides are coated by extracellular polymeric substances in which the microbial cells are embedded. Covellite crystals have nucleated within these microbial aggregates, accreting and forming large crystals attached to the vein walls. These results strongly suggest that in situ microbial sulfate reduction can control the formation of secondary copper deposits. Equivalent processes could be widespread in similar deposits elsewhere, but they are probably overlooked due to the presumed low capability for fossilization of the microbes.Torsvik, T.H., Cocks, L.R.M., 2019. The integration of palaeomagnetism, the geological record and mantle tomography in the location of ancient continents. Geological Magazine 156, 242-260. palaeogeographical maps is best achieved through the integration of data from hotspotting (since the Cretaceous), palaeomagnetism (including ocean-floor magnetic anomalies since the Jurassic), and the analysis of fossils and identification of their faunal and floral provinces; as well as a host of other geological information, not least the characters of the rocks themselves. Recently developed techniques now also allow us to determine more objectively the palaeolongitude of continents from the time of Pangaea onwards, which palaeomagnetism alone does not reveal. This together with new methods to estimate true polar wander have led to hybrid mantle plate motion frames that demonstrate that TUZO and JASON, two antipodal thermochemical piles in the deep mantle, have been stable for at least 300?Ma, and where deep plumes sourcing large igneous provinces and kimberlites are mostly derived from their margins. This remarkable observation has led to the plume generation zone reconstruction method which exploits the fundamental link between surface and deep mantle processes to allow determination of palaeolongitudes, unlocking a way forward in modelling absolute plate motions prior to the assembly of Pangaea. The plume generation zone method is a novel way to derive ‘absolute’ plate motions in a mantle reference frame before Pangaea, but the technique assumes that the margins of TUZO and JASON did not move much and that Earth was a degree-2 planet, as today.Totani, T., Omiya, H., Sudoh, T., Kobayashi, M.A.R., Nagashima, M., 2018. Lethal radiation from nearby supernovae helps explain the small cosmological constant. Astrobiology 19, 126-131. observed value Λobs of the cosmological constant Λ is extremely smaller than theoretical expectations, and the anthropic argument has been proposed as a solution to this problem because galaxies do not form when Λ???Λobs. However, the contemporary galaxy formation theory predicts that stars form even with a high value of Λ/Λobs ～ 50, which makes the anthropic argument less persuasive. Here we calculate the probability distribution of Λ using a model of cosmological galaxy formation, considering extinction of observers caused by radiation from nearby supernovae. The life survival probability decreases in a large Λ universe because of higher stellar density. Using a reasonable rate of lethal supernovae, we find that the mean expectation value of Λ can be close to Λobs; hence this effect may be essential to understand the small but nonzero value of Λ. It is predicted that we are located on the edge of habitable regions about stellar density in the Galaxy, which may be tested by future exoplanet studies.Troll, V.R., Emeleus, C.H., Nicoll, G.R., Mattsson, T., Ellam, R.M., Donaldson, C.H., Harris, C., 2019. A large explosive silicic eruption in the British Palaeogene Igneous Province. Scientific Reports 9, Article 494. pyroclastic eruptions are not known from the basalt-dominated British Palaeogene Igneous Province (BPIP), although silicic magmatism is documented from intra-caldera successions in central volcanoes and from small-volume ash-layers in the associated lava fields. Exceptions are the Sgùrr of Eigg (58.7?Ma) and ?igh-sgeir pitchstones in the Inner Hebrides (>30?km apart), which have been conjectured to represent remnants of a single large silicic event. Currently available major element data from these outcrops differ, however, creating a need to test if the two pitchstones are really related. We employ a systematic array of methods ranging from mineralogy to isotope geochemistry and find that samples from the two outcrops display identical mineral textures and compositions, major- and trace elements, and Sr-Nd-Pb-O isotope ratios, supporting that the two outcrops represent a single, formerly extensive, pyroclastic deposit. Available isotope constraints suggest a vent in the Hebridean Terrane and available radiometric ages point to Skye, ~40?km to the North. A reconstructed eruption volume of ≥5km3 DRE is derived, suggesting a VEI 5 event or larger. We therefore argue, contrary to long-held perception, that large-volume silicic volcanism and its associated climatic effects were likely integral to the BPIP during the opening of the North Atlantic.Trujillo-Rodríguez, M.J., Nan, H., Varona, M., Emaus, M.N., Souza, I.D., Anderson, J.L., 2019. Advances of ionic liquids in analytical chemistry. Analytical Chemistry 90, 505-531. liquids (ILs) are a highly unique class of nonmolecular solvents that possess melting points below 100 °C. ILs that have melting points below room temperature are often referred to as room temperature ionic liquids (RTILs). ILs possess a wide variety of unique physicochemical properties, including low or negligible vapor pressure at room temperature, high thermal and electrochemical stability, and high conductivity.ILs are composed completely of ions and are typically asymmetric organic cations containing nitrogen or phosphorus heteroatoms as well as both inorganic and organic anions. Figure 1 shows a representative series of typical IL cations and anions. Due to the large diversity of cations and anions, it has been estimated that more than 1018 possible combinations of cations and anions can be created. It is often the case that small modifications to the cation/anion chemical structure or cation/anion combination are accompanied by dramatic modifications to their physical properties, including viscosity and water solubility. At the same time, the incorporation of polar or nonpolar moieties to the IL structure can promote different interactions with solutes and impressive solvation capabilities for different classes of compounds. For all of these reasons, ILs are often referred to as designer solvents.Tully, B.J., 2019. Metabolic diversity within the globally abundant Marine Group II Euryarchaea offers insight into ecological patterns. Nature Communications 10, Article 271. their discovery over 25 years ago, the Marine Group II Euryarchaea (MGII) remain a difficult group of organisms to study, lacking cultured isolates and genome references. The MGII have been identified in marine samples from around the world, and evidence supports a photoheterotrophic lifestyle combining phototrophy via proteorhodopsins with the remineralization of high molecular weight organic matter. Divided between two clades, the MGII have distinct ecological patterns that are not understood based on the limited number of available genomes. Here, I present a comparative genomic analysis of 250 MGII genomes, providing a comprehensive investigation of these mesophilic archaea. This analysis identifies 17 distinct subclades including nine subclades that previously lacked reference genomes. The metabolic potential and distribution of the MGII genera reveals distinct roles in the environment, identifying algal-saccharide-degrading coastal subclades, protein-degrading oligotrophic surface ocean subclades, and mesopelagic subclades lacking proteorhodopsins, common in all other subclades.?jvári, G., Kele, S., Bernasconi, S.M., Haszpra, L., Novothny, ?., Bradák, B., 2019. Clumped isotope paleotemperatures from MIS 5 soil carbonates in southern Hungary. Palaeogeography, Palaeoclimatology, Palaeoecology 518, 72-81. paleotemperature reconstructions for the continents, including East Central Europe, over marine isotope stage 5 (MIS 5) and specifically the last interglacial (LIG, MIS 5e) are scarce and mostly based on pollen assemblages. Here we provide soil and air temperature\ reconstructions for the summer season of MIS 5e (5c) using carbonate clumped isotope thermometry applied to soil carbonate concretions in the Dunaszekcs? loess-paleosol record, Southern Hungary. The sediments making up the S1 pedocomplex investigated represent the MIS 5 as demonstrated by bracketing K-feldspar post-IR-IRSL225/290 ages of ~63 to 164?ka. Both the absolute ages and pedogenic susceptibility (χP) curve indicate that all the subtages of MIS 5 were found to be recorded in the sequence, and soil carbonates found >1?m depth below the paleosurface of the S1 soil provide pristine, undisturbed isotopic signals. The soil carbonate concretions likely formed during MIS 5e at a relatively shallow (20–50?cm) depth, but a later formation during MIS 5c at >50?cm depth is also plausible. Clumped isotope-based soil temperatures (ST-Δ47sc) ranged from 16 to 20?°C, and reconstructed summer season air temperatures (SATs) for the LIG are consistently lower than the modern values at the site by ~1–5?°C, matching surprisingly well the soil bacteria membrane lipid-based MIS 5e air temperature estimates from a nearby Serbian site. At the same time, the reconstructed SAT values do not match the 2–4?°C positive warm season anomalies modeled for East Central Europe between LIG and present-day in paleoclimate simulations. ST uncertainties of 1–6?°C, infiltration-driven cooling of soil temperatures, and the possibility of MIS 5c formation of the investigated carbonates may account for this proxy-model data discrepancy. Oxygen isotope compositions of summer season paleo-rainwaters for MIS 5e (5c), as reconstructed using the ST-Δ47sc and δ18Osc data of soil carbonates, were found in a range of ?6.7 and ?6.4‰, matching the modern mean summer season value of ?6.2?±?0.94‰ within error.Urakawa, H., Rajan, S., Feeney, M.E., Sobecky, P.A., Mortazavi, B., 2019. Ecological response of nitrification to oil spills and its impact on the nitrogen cycle. Environmental Microbiology 21, 18-33. oil spills are catastrophic events that cause massive damage to ecosystems at all trophic levels. While most of the research has focused on carbon-degrading microorganisms, the potential impacts of hydrocarbons on microbes responsible for nitrification have received far less attention. Nitrifiers are sensitive to hydrocarbon toxicity: ammonia-oxidizing bacteria and archaea being 100 and 1000 times more sensitive than typical heterotrophs respectively. Field studies have demonstrated the response of nitrifiers to hydrocarbons is highly variable and the loss of nitrification activity in coastal ecosystems can be restored within 1?2 years, which is much shorter than the typical recovery time of whole ecosystems (e.g., up to 20 years). Since the denitrification process is mainly driven by heterotrophs, which are more resistant to hydrocarbon toxicity than nitrifiers, the inhibition of nitrification may slow down the nitrogen turnover and increase ammonia availability, which supports the growth of oil-degrading heterotrophs and possibly various phototrophs. A better understanding of the ecological response of nitrification is paramount in predicting impacts of oil spills on the nitrogen cycle under oil spill conditions, and in improving current bioremediation practices.Vakhin, А.V., Aliev, F.A., Kudryashov, S.I., Afanasiev, I.S., Petrashov, O.V., Sitnov, S.A., Mukhamatdinov, I.I., Varfolomeev, M.A., Nurgaliev, D.K., 2018. Aquathermolysis of heavy oil in reservoir conditions with the use of oil-soluble catalysts: part I – changes in composition of saturated hydrocarbons. Petroleum Science and Technology 36, 1829-1836. paper is devoted to the study of aquathermolysis processes of heavy oil produced by CSS technology on Boca de Jaruco oil field. Various catalysts based on cobalt, nickel, iron and copper were used for intensification of in-situ upgrading processes of heavy oil. The first paper in series is presented results of transformation of crude oil and its saturate fraction after thermal treatment with and without catalysts by SARA analysis, MALDI mass-spectrometry, FTIR-spectroscopy and gas chromatography. It is revealed, that catalysts provide more deep conversion of asphaltenes and resins into lighter hydrocarbons. Particularly, for the given heavy oil, catalysts based on iron and nickel organic salts are more effective to reduce the content of high molecular weight components (asphaltenes). Saturates fraction after thermal treatment in presence of the catalysts is enriched with lighter alkanes in comparison to the crude oil treated without catalysts. Obtained results show that crude oil recovered by catalytic aquathermolysis processes will be better quality than the original oil in the place.Van de Velde, T., Deschepper, E., Mestdagh, B., De Clercq, W., Vandenabeele, P., Lynen, F., 2019. Lipids, funerals, gifts and feasts. Organic residue analysis on Merovingian ceramics from the Elversele burial field (Belgium). Journal of Archaeological Science: Reports 24, 30-38. the excavation of a Merovingian cemetery in Elversele (Temse, Belgium), archaeologists encountered nine burials each with one earthenware vessel clearly deposited in the graves, dating to the 6th–7th century AD. Vessels as grave goods are often linked with funerary feasting in Merovingian contexts, the contents of the vessels than acting as funerary meals in gift-giving relationships. However, as the custom of depositing vessels seems to diminish throughout the 6th and 7th century, it has been suggested that such vessels in most cases functioned only symbolically and that they held no actual foodstuffs. In order to verify or debunk this hypothesis, eight of the nine vessels from Elversele were sampled for organic residue analysis. Gas Chromatography – Mass Spectrometry (GC–MS) was used on the archaeological samples and various organic compounds related to foodstuffs were identified. This was complemented with an archaeological assessment of the pottery. Traces of animal fats and possibly also vegetal matter have been attested and, together with the results of the archaeological assessment, form clear evidence for the deposition of foodstuffs in these graves.Vandergrift, G.W., Monaghan, J., Krogh, E.T., Gill, C.G., 2018. Direct analysis of polyaromatic hydrocarbons in soil and aqueous samples using condensed phase membrane introduction tandem mass spectrometry with low-energy liquid electron ionization. Analytical Chemistry 91, 1587-1594. hydrocarbons (PAHs) are listed as priority pollutants by the United States Environmental Protection Agency (U.S. EPA). PAH-contaminated samples often require extensive sample cleanup before analysis, with the method used dependent upon the sample matrix. We present condensed phase membrane introduction mass spectrometry with liquid electron ionization (CP-MIMS–LEI) as a sensitive and universal technique that can directly analyze both aqueous and soil samples for PAHs without the need for sample clean up or instrumental modifications for different matrixes. The method uses a semipermeable hollow fiber membrane immersion probe to transfer analytes from complex samples into a solvent acceptor phase that is directly entrained at nanoliter/min flows to an LEI-interfaced mass spectrometer. The resulting aerosol is desolvated under vacuum leading to analyte vaporization and subsequent electron ionization. Electron energy and LEI vaporization capillary position were examined and optimized for PAHs. The CP-MIMS probe was directly immersed in complex aqueous matrixes, demonstrating low nanogram per liter PAH detection limits and response times of ≤1.6 min. For soil sample analysis, 2-propanol was found to be the optimal PAH sampling solvent. Soil samples were briefly sonicated in 2-propanol, followed by direct CP-MIMS measurement. Soil sample throughput was ca. 15 samples/h, with PAH quantitation successful at microgram per kilogram levels. The workflow is remarkably simple, fast, green, and leads to reproducible results that enable high-throughput screening of heterogeneous soil samples.Vérard, C., 2019. Panalesis: towards global synthetic palaeogeographies using integration and coupling of manifold models. Geological Magazine 156, 320-330. reconstructions have been proposed for years. The technique employed, however, is more or less always the same: it consists of determining the palaeoenvironment at the local scale and extending it to the regional scale. Such work is carried out in a maximum number of locations all over the planet and the global palaeogeography is the result of interpolation of those reconstructions. Advances in palaeogeography can be made via an alternative way, which consists of integrating and then coupling various global models. It results in the proposal of synthetic palaeogeographies that can be compared a posteriori to local or regional data. The advantage is twofold: (1) the view is really global and it avoids gaps (in particular in the oceanic realm) in the reconstructions, and it is very much less focused on the coastline; (2) it takes advantages from almost all the fields of geosciences, so that reconstructions can be constrained from a large variety of data. The two techniques – the ‘classic’ and the ‘alternative’ – are not contradictory but complementary, and it is desirable that one feeds the other and the study of palaeogeography be revived.Vérard, C., 2019. Plate tectonic modelling: review and perspectives. Geological Magazine 156, 208-241. the 1970s, numerous global plate tectonic models have been proposed to reconstruct the Earth's evolution through deep time. The reconstructions have proven immensely useful for the scientific community. However, we are now at a time when plate tectonic models must take a new step forward. There are two types of reconstructions: those using a ‘single control’ approach and those with a ‘dual control’ approach. Models using the ‘single control’ approach compile quantitative and/or semi-quantitative data from the present-day world and transfer them to the chosen time slices back in time. The reconstructions focus therefore on the position of tectonic elements but may ignore (partially or entirely) tectonic plates and in particular closed tectonic plate boundaries. For the readers, continents seem to float on the Earth's surface. Hence, the resulting maps look closer to what Alfred Wegener did in the early twentieth century and confuse many people, particularly the general public. With the ‘dual control’ approach, not only are data from the present-day world transferred back to the chosen time slices, but closed plate tectonic boundaries are defined iteratively from one reconstruction to the next. Thus, reconstructions benefit from the wealth of the plate tectonic theory. They are physically coherent and are suited to the new frontier of global reconstruction: the coupling of plate tectonic models with other global models. A joint effort of the whole community of geosciences will surely be necessary to develop the next generation of plate tectonic models.Verchovsky, A.B., Goltsin, N.A., Prasolov, E.M., Lokhov, K.I., 2018. Nitrogen isotopic composition of shungite from the Onega structure, Russia, and the origin of the organic matter. Geochemistry International 56, 1341-1353. paper presents first nitrogen isotope analyses in shungites sampled from the core material of boreholes and from adits in the Onega region, Russia. The samples represent all varieties of the rocks, both stratified and migrated, with concentrations of reduced carbon ranging from a few percent to almost 100%. Analyses were carried out on a mass spectrometric complex (designed at the Open University), with the simultaneous measurements of the isotopic composition and concentrations of nitrogen and carbon using the step oxidation technique. It was determined that nitrogen is released mostly when the carbon is oxidized. The individual samples differ from one another in nitrogen isotopic composition and the nitrogen/carbon ratio, which indicates that these samples contain three distinct organic components of biological origin. Variations in δ15N and C/N that correspond to mixing of organic matter of the three types have been also observed during stepped oxidation. One of them has a relatively low C/N of approximately 200 and contains isotopically light nitrogen (δ15N up to –10‰). This component is thought to be primary, produced when the shungite rocks have been formed in a biological cycle involving reduced nitrogen species and formation of chemoautolithotrophic organisms, similar to what nowadays takes places in hydrothermal systems related to volcanic activity in spreading zones in the seafloor. Another component of the organic matter, with a relatively high δ15N from 0 to +3‰ and C/N of approximately 1000, was likely derived from the primary one in the course of diagenesis and metamorphism, due to nitrogen losses, resulted in heavier isotopic composition of the residual nitrogen. Finally, during post metamorphism time, the shungites have been contaminated with organic matter brought by meteoric waters. This organic matter had a relatively high δ15N of approximately +10‰ and the lowest C/N < 50. The different oxidation temperatures of the three organic components explain the reason for the variations in δ15N and C/N during step combustion of the material.Vereyken, L., Dillen, L., Vreeken, R.J., Cuyckens, F., 2019. High-resolution mass spectrometry quantification: Impact of differences in data processing of centroid and continuum data. Journal of The American Society for Mass Spectrometry 30, 203-212. mass spectrometry (HRMS) in full scan mode acquires all ions present in the sample of interest offering a lot of qualitative information. This, in combination with the improved performance of the new generation HRMS systems, triggers more (bio) analysts to switch from triple quad MS systems to HRMS for quantitative analysis. Quantitative processing of HRMS data is performed based on narrow mass extraction windows rather than on nominal mass product ion chromatograms (SRM or MRM). Optimal processing of HRMS data requires different considerations and software tools and can have an impact on data processing and final results. The selection of centroid versus continuum/profile data for processing, selection of the optimal narrow mass extraction window, using theoretical versus measured accurate mass for the extraction of the ion chromatograms as well as differences in calculations and data handling residing in the different vendor software packages are tackled in the presented manuscript. These differences are illustrated on HRMS data acquired for the same plasma samples on three different platforms, i.e., a Sciex QToF, a Waters QToF, and a Thermo Orbitrap system, and processed in four different software packages, i.e., Sciex Analyst? TF, Waters Masslynx, Waters Unifi, and Thermo Xcalibur. The impact of these differences on quantitative HRMS performance was evaluated on calibration curves of eight small molecule compounds in plasma using four different ways of processing. Simple guidelines are provided for the selection of an optimal mass extraction window for continuum and centroided data.Viehmann, S., Hohl, S.V., Kraemer, D., Bau, M., Walde, D.H.G., Galer, S.J.G., Jiang, S.-Y., Meister, P., 2019. Metal cycling in Mesoproterozoic microbial habitats: Insights from trace elements and stable Cd isotopes in stromatolites. Gondwana Research 67, 101-114. the environmental conditions that supported early life on Earth relies on well-preserved geochemical archives in the rock record. However, many geochemical tracers either lack specificity or they are affected by post-depositional alteration. We present a data set of major and trace element abundances and Cd isotope compositions of dome-shaped and conophyton-type stromatolites of the Late Mesoproterozoic Paranoá Group (Brazil), showing distinct values with unprecedented resolution at the lamina scale.The studied stromatolites consist of dolomite with a high purity and a negligible content of immobile elements (e.g., <0.66?ppm Zr), indicating that elemental compositions are not influenced by detrital contamination. Even though the carbonates have experienced different extent of recrystallization, the measured elemental and isotopic compositions do not correlate with fluid mobile elements. The stromatolites thus represent prime archives for geochemical proxies to reconstruct paleo-environmental conditions.Two endmember compositions can be distinguished by multiple proxy analysis, reflecting the contrasting depositional environments of the two types of stromatolites: Shale-normalized rare earth elements including yttrium (REYSN) patterns of domal stromatolites show a light REYSN (LREY) enrichment (YbSN/PrSN?<?0.84), slightly super-chondritic Y/Ho ratios (33.6–39.3) and unfractionated Cd isotopes relative to upper continental crust. This indicates that the stromatolites formed in a shallow-water environment that was episodically influenced by seawater. Their REY and Cd compositions are dominated by dissolved elements that were delivered via weathering and erosion processes from the ambient continent.In contrast, REYSN patterns of the conophyta are parallel those of modern seawater with an LREYSN depletion relative to HREYSN (YbSN/PrSN?=?2.1 to 3.9), positive GdSN anomalies (1.1 to 1.4) and strong super-chondritic Y/Ho ratios (37.9 to 46.2), suggesting a microbial habitat that was dominated by seawater. Cd isotopes correlate negatively with Cd and U, but positively with Mn and Ce concentrations, reflecting authigenic carbonate formation at different depths within a redox gradient of the ancient microbial mat. ε112/110Cddol values increase from ?3.52 at the mat surface to +3.46 in the interior of the mat, due to the effect of kinetic fractionation during Cd-uptake, e.g. by adsorption onto organic matter or by precipitation of sulfides, in addition to incorporation into carbonate minerals. Hence, our multi-proxy approach including Cd isotopes bears a high potential to shed light on environmental conditions in ancient microbial habitats and the activity of microbial life on Early Earth.Vitale, C.M., Di Guardo, A., 2019. Predicting dissolved organic carbon partition and distribution coefficients of neutral and ionizable organic chemicals. Science of The Total Environment 658, 1056-1063. KDOC (dissolved organic carbon/water partition coefficient) and DDOC (dissolved organic carbon/water distribution coefficient) of neutral and ionizable organic chemicals is a crucial task for assessing mobility, modelling transport, environmental fate of a variety of chemicals and for evaluating their bioavailability in terrestrial and aquatic environments. A critical literature search of reliability-selected KDOC and DDOC values was performed to setup novel predictive relationships KDOC KDOC and DDOC of neutral and ionizable organic chemicals. This goal was pursued by using: 1) LSER (linear solvation energy relationship) models to predict KDOC for neutral chemicals using Abraham solute parameters calculated for different DOC sources (all DOC sources together, soil porewater, surface water, wastewater and Aldrich humic acid (HA)); 2) linear regressions for predicting DDOC of organic acids from the octanol/water partition coefficient (Log KOW or Log P) and the dissociation constant (pKa), accounting separately for the contribution of the neutral and ionic fraction. The proposed models predicted Log KDOC and DDOC values within a root mean square deviation (RMSD) generally smaller than 0.3 log units.Vorobyova, E.A., Cheptsov, V.S., Osipov, G.A., Kotsyurbenko, O.R., Soina, V.S., 2018. Gamma-IR resistance of bacteria in soil and permafrost. Paleontological Journal 52, 1204-1216. radiation is among the most important planetary factors that regulate the intensity and dynamics of biospheric processes. At the early stages of life on the Earth, short-wave radiation permeated the Earth surface. The evolution of the planet, corrected by fluctuations of cosmophysical factors, contributed to the development of the adaptation processes in the emerging biosystems, including resistance to a wide range of ionizing effects. Studies of microorganisms from extreme habitats have changed the scientific paradigm of cell viability and adaptive potential. The taxonomic spectrum of bacteria and archaea, isolated from extreme biotopes and resistant to ionizing radiation, is constantly enlarged. However, it is also necessary to develop in?situ studies at the system level, as well as to assess the ecosystem stability and prospects for its restoration as the basic unit of the biosphere during prolonged exposure to radiation and accumulation of significant doses. The goal of this research was to study the effects of high doses (60?250 kGy) of ionizing gamma radiation on the viability of bacterial communities in frozen sedimentary rocks and modern soils, as well as to assess the aftereffect of high doses on natural samples.Vorrath, M.E., Müller, J., Esper, O., Mollenhauer, G., Haas, C., Schefu?, E., Fahl, K., 2019. Highly branched isoprenoids for Southern Ocean semi-quantitative sea ice reconstructions: a pilot study from the Western Antarctic Peninsula. Biogeosciences Discussions 2019, 1-33. geochemical and micropaleontological analyses of surface sediments collected in the southern Drake Passage and the Bransfield Strait, Antarctic Peninsula, enable a proxy-based reconstruction of recent sea ice conditions in this climate sensitive area. The distribution of the sea ice biomarker IPSO25 supports earlier suggestions that the source diatoms seem to be common in near-coastal environments characterized by an annually recurring sea ice cover. We here propose and evaluate the combination of IPSO25 with a more unsaturated highly branched isoprenoid alkene and phytosterols and introduce the PIPSO25 index as a potentially semi-quantitative sea ice proxy. This organic geochemical approach is complemented with diatom data. PIPSO25 sea ice estimates are used to discriminate between areas characterized by permanently ice-free conditions, seasonal sea ice cover and extended sea ice cover. These trends are consistent with satellite sea ice data and winter sea ice concentrations estimated by diatom transfer functions. Minor offsets between proxy-based and satellite-based sea ice data are attributed to the different time intervals recorded within the sediments and the instrumental records from the study area, which experienced rapid environmental changes during the past 100 years.Wan, L., Liu, Z., Liu, J., Sun, W., Liu, B., 2019. On the linearity of the temperature response in Holocene: the spatial and temporal dependence. Climate of the Past Discussions 2019, 1-18. studies show that the evolution of global mean temperature forced by the total forcing is almost the same as the sum of those forced by individual forcing in the last 21000 years as simulated in three independent climate models, CCSM3, FAMOUS and LOVECLIM. But how does the linearity of the climate response depend on the spatial and temporal scales quantitatively and in what regions the linear response tends to dominate remain unknown. Here, based on the TraCE-21ka climate simulation outputs, the spatial and temporal dependence of the linear response of temperature evolution in the Holocene is studied using correlation coefficient and a linear error index. The results show that the linear response of global mean temperature is strong on the orbital, millennial and centennial scales throughout the Holocene, but is poor on the decadal scale. The linear response differs significantly between the Northern Hemisphere (NH) and Southern Hemisphere (SH). In the NH, the linear response is strong on millennial scale, while in the SH the linear response is strong on orbital scale, such that the linear response of the global mean orbital variability is dominated by the SH response, but that of the global millennial variability seems dominated by the NH response. Furthermore, at the regional scales, the linear responses differ substantially between the orbital, millennial, centennial and decadal timescales. On the orbital scale, the linear response is dominant for most regions, even at the small area of about a mid-size country like Germany. On the millennial scale, the linear response is still strong in the NH over many regions, albeit weaker than on the orbital scale. However, the millennial variability shows relatively poor linear response over most regions in the SH. On the centennial and decadal timescales, the linear response is no longer significant in almost all the regions. The regions of strong linear response on the millennial scale are mostly consistent with those on the orbital scale, notably western Eurasian, North Africa, subtropical North Pacific, tropical Atlantic and Indian Ocean, because of a large signal-to-noise ratios over these regions. This finding can improve our understanding of the regional climate response to various climate forcings in the Holocene.Wan, Y., Wu, N., Hu, G., Xin, X., Jin, G., Liu, C., Chen, Q., 2018. Reservoir stability in the process of natural gas hydrate production by depressurization in the shenhu area of the south China sea. Natural Gas Industry B 5, 631-643. stability is a key factor in the production of natural gas hydrate (NGH), and also a prerequisite to ensuring safe and efficient NGH production. However, it has been rarely discussed. To analyze the reservoir stability in the process of NGH production by depressurization in the Shenhu area of the South China Sea, we established a 3D geological model of NGH production by depressurization on the basis of NGH drilling data in this area, which was then discretized by means of nonstructural grid. Then, the mathematical model coupling four fields (i.e. thermal, hydraulic, solid and chemical) was established considering the heat and mass transfer process and sediment transformation process during NGH production. The model was solved by the finite element method together with the nonstructural grid technology, and thus the time-space evolution characteristics of reservoir pore pressure, temperature, NGH saturation and stress in the condition of NGH production by depressurization were determined. Finally, reservoir subsidence, stress distribution and stability in the process of NGH production by depressurization in the Shenhu area were analyzed. The results obtained are as follows. First, the higher the reservoir permeability and the larger the bottomhole pressure drop amplitude are, the larger the subsidence amount and the higher the subsiding speed. Second, as the reservoir pore pressure decreases in the process of production, the effective stress increases and the shear stress near the well increases obviously, resulting in shear damage easily. Third, the increase of effective reservoir stress leads to reservoir subsidence, which mainly occurs in the early stage of NGH production. After the production for 60 days, the maximum reservoir subsidence reached 32?mm and the maximum subsidence of seabed surface was 14?mm. In conclusion, the NGH reservoirs in the Shenhu area of the South China Sea are of low permeability and the effect range of reservoir pressure drop is limited, so the reservoirs would not suffer from shear damage in the sixty-day-production period.Wan, Z., Yao, Y., Chen, K., Zhong, S., Xia, B., Sun, Y., 2019. Characterization of mud volcanoes in the northern Zhongjiannan Basin, western South China Sea. Geological Journal 54, 177-189. volcanoes are important to understand hydrocarbon research and exploration, crustal movement and neotectonic activity, geological engineering, and climate change. They are widely distributed along the Alps-Tethys suture zone, the Pacific belt, and continental slopes. Previous detailed studies on mud volcanoes concentrated mostly on onshore areas. Recent developments in geophysical technology have opened vast deepwater areas for research on mud volcanoes. Based on multibeam bathymetry, multichannel seismic reflection, gravity, and magnetics data, mud volcanoes in the northern Zhongjiannan Basin have been studied comprehensively and systematically. Abundant mud volcanoes were found in the whole Northern Depression of the basin, not only in the Zhongjian Valley but also in the Rizhao Valley, with different sizes, morphologies, and eruption intensities. Five types of mud volcanoes are identified in the study area, which include the following: deep source high-energy large-size mud volcanoes, shallow source low-energy small-size mud volcanoes, budding mud volcanoes (mud diapir), mud volcanoes related to canyon and bottom current channels, and mud volcanoes related to pockmarks and gas chimneys. At the developmental scale, the distribution and type of mud volcanoes (diapirs) in the Zhongjiannan Basin are obviously different than those in the Yinggehai Basin, which is famous for the development of a large number of large mud diapirs in the North-western South China Sea. The region's tectonic and sedimentary environment is the main controlling factor of the development of mud volcanoes. Three sets of Tertiary thick mudstones in the Zhongjiannan Basin are the material basis for the formation of mud volcanoes. Overpressured fluid, generated from the combined factors of undercompaction, hydrocarbon generation, hydrothermal pressurization, and tectonic compression, is the driving force of the eruption of mud volcanoes. Furthermore, earthquakes that occurred in the surrounding areas of the Zhongjiannan Basin are the triggering mechanism of mud volcano eruptions.Wang, B., Cui, H., Liu, H., Wan, Y., 2018. Derivatization for nontargeted screening of acids in oilfield refinery wastewater: Identification and behaviors of recalcitrant chlorinated naphthenic acids. Environmental Science & Technology 53, 1022-1030. nontargeted scanning chemical profiling approach has shown great potential to identify unknown pollutants or novel biological markers; however, the structure identification of unknown compounds is a challenge. In this study, a carboxyl-specific derivatization reagent, N-(4-aminomethylphenyl) pyridinium (AMPP), was coupled with QTOF–MSE–MS scanning to establish a high-throughput nontargeted scanning method for acid compounds. The scanning method can isolate the precursor by data-independent acquisition and can select all of the acid compounds based on the characteristic ragment generated from the derivatization reagent. The method was applied to scan naphthenic acid fraction compounds in petroleum refinery wastewater and identify 70–126 NAs, 30–68 oxy-NAs, 54–60 NAs containing nitrogen, and 66–75 NAs containing both nitrogen and oxygen. Chlorinated NAs (Cl-NAs) including monochlorinated NAs (Cl-NAs), monochlorinated hydroxylated NAs (Cl–OH-NAs), and dichlorinated dihydroxylated NAs (Cl2-(OH)2-NAs) were first identified with the aid of chlorine isotopic patterns. The Cl-NAs might be naturally presented in crude oil together with NAs. Occurrences and mass balances of Cl-NAs were further assessed in the wastewater treatment plant in north China. The total concentrations of ∑Cl-NAs were estimated to be 12 ± 7.8–18 ± 17 μg/L and 8.5 ± 2.0–68 ± 35 μg/g in the wastewater and solid samples, respectively. The removal efficiencies of Cl-NAs (?29.9 to 34.3%) were much lower than those of NAs, suggesting the high recalcitrance of chlorinated compounds during the treatment processes. The estimated mass loss fractions due to degradation for Cl-NAs were 26.5–53.4% of initial loadings, and relatively high fractions (32.1–56.8%) were observed in the effluent directly discharged to the environment. Advanced treatment techniques are needed to effectively reduce the persistent Cl-NAs in the wastewater.Wang, B., Zhang, Q., Wang, G., Liu, M., 2018. Analysis on the difference of material composition and reservoir space of Mesoproterozoic dark marine shale in the Yanshan area. Energy Exploration & Exploitation 37, 332-354. dark marine shales which are thick in the Mesoproterozoic Hongshuizhuang formation and Xiamaling Formation in the Yanshan area are the subject of this study. The material compositions and pore characteristics were analyzed, and the reasons for the differences in the adsorption capacity of shale were emphatically discussed through geochemical analysis, X-ray diffraction, scanning electron microscope, low-temperature nitrogen adsorption, mercury injection experiment, isothermal adsorption, and other analysis methods. The results indicate that the samples are rich in high organic carbon content, and vitrinite reflectance suggests that the degree of thermal evolution is in the late-mature to high-mature stage; the mineral compositions mainly consist of quartz and clay minerals. The micropores are relatively developed, which mainly include intergranular pores, intragranular pores, microcracks, and many other pores. Results from the nitrogen adsorption analysis suggest that the pore structures can be divided into three types. Porosity has obvious fractal characteristics. The fractal dimensions of the adsorption pore are larger than those of the seepage hole. The difference of shale adsorption between the Hongshuizhuang Formation and Xiamaling Formation is mainly determined by the volume of micropores and transition pores and the different mineral compositions.Wang, F., Guo, S., 2019. Influential factors and model of shale pore evolution: A case study of a continental shale from the Ordos Basin. Marine and Petroleum Geology 102, 271-282. characteristics have a significant influence on the occurrence and enrichment of shale gas. Therefore, these characteristics are key parameters in shale reservoir evaluation and have important research significance. Taking a continental shale sample from the Ordos Basin, China as an example, this research used low-pressure CO2/N2 adsorption, high-pressure mercury intrusion porosimetry (MIP), vitrinite reflectance (Ro) analysis, hydrocarbon generation measurements, X-ray diffraction analysis and argon ion polishing-field emission scanning electron microscopy (AIP-FESEM) in conjunction with a thermal simulation experiment to study pore characteristics. Through the above analyses, this study achieved a whole-aperture dynamic characterization of the shale pores and discussed the characteristics of the shale pore distribution and evolution through geological history. Then, the factors influencing pore evolution were analysed and a pore evolution model was established. The results showed that the micropores and mesopores provided the majority of the surface area in the sample, while the mesopores and macropores provided the majority of the pore volume in the sample. During the thermal simulation experiment, pore evolution was dominated by the hydrocarbon generation by organic matter, the transformation of minerals and compaction. According to the pore evolution characteristics and the main influential factors during the thermal simulation experiment, the pore evolution model can be divided into four stages. The characteristics of the micropores, mesopores, macropores and the influential factors differ in each stage.Wang, H., Taborda, E.A., Alvarado, V., Cortés, F.B., 2019. Influence of silica nanoparticles on heavy oil microrheology via time-domain NMR T2 and diffusion probes. Fuel 241, 962-972. objective of the present work is to determine the effect of silica nanoparticles on the microrheological properties of heavy and extra-heavy crude oils using time-domain nuclear magnetic resonance (TD-NMR) methods. Three heavy crude oils with different asphaltene contents were studied. The oils steady-state rheograms were collected as a function temperature and nanoparticles concentration. Transverse relaxation time (T2) and diffusion coefficient measurements were used as probes of the crude oils microrheological responses. A clear inverse correlation between either the log-mean T2 (T2,LM) or the diffusion coefficient and the rheometric oil viscosity in the presence of nanoparticles was found. Results further show the likely existence of an optimal concentration of nanoparticles in the vicinity of 1000?mg/L. The maximum viscosity reduction of roughly 35–45% was observed for the three heavy crude oils. The heavy oil refractive index decreases after the oil was placed in contact with nanoparticles, confirming adsorption of polar material on nanoparticles. T2 and the diffusion coefficient increase in the apparent region of optimal concentration of nanoparticles and decrease at higher concentration. The improved NMR responses, which reflect the enhanced translational and rotational motion of restricted hydrogen-bearing oil molecules/aggregates proves that microrheological changes occur as oil polar molecules aggregates break down due to the adsorption of asphaltenes. Finally, a multivariate statistical analysis evidences which parameter has the greatest influence on the system response. It is the first time, to the best of our knowledge, that these characterization tools have been used in heavy crude oils in the presence of nanoparticles.Wang, I.W., Kutteri, D.A., Gao, B., Tian, H., Hu, J., 2019. Methane pyrolysis for carbon nanotubes and COx-Free H2 over transition-metal catalysts. Energy & Fuels 33, 197-205., researchers at West Virginia University reported a promising catalyst innovation for nonoxidative thermochemical conversion of methane to CO2-free hydrogen and solid carbon nanotubes (CNTs). A catalyst system was discovered that promotes “base growth” CNT formation rather than conventional “tip growth”. This enables catalyst regenerability while also generating highly pure and crystalline carbon products. In this study, simultaneous productions of CNTs and CO2-free hydrogen were studied over Fe-based catalysts supported on Al2O3, SiO2, and H-ZSM-5. The experimental results showed that metal–support interaction played a key role in the base growth mechanism. Methane conversion and the property of CNTs depended significantly on metal loading and the type of support. To elucidate the formation mechanism of CNTs, the spent catalysts were characterized by a number of analytical instrumentations including transmission electron microscopy, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), Raman spectroscopy, and thermogravimetric analysis (TGA). The formation of the active intermediate phase, Fe3C, was discovered. The results of XPS analysis revealed that Fe/Al2O3 had a stronger interaction between metal particles and support than Fe/SiO2 and Fe/ZSM-5. The characterization result is consistent with the performance test results from the methane decomposition reaction. To further explore the application of the CNTs, separation and purification were carried out using spent Fe/Al2O3 and 9Ni-1Fe/SiO2 catalysts. The spent catalysts with CNTs were separated by refluxing in nitric acid. The purity of CNTs recovered from the Fe/Al2O3 catalyst can reach 96% based on TGA analysis. XRD and scanning electron microscopy–energy-dispersive system analyses (SEM-EDS) revealed that most metal particles and supports had been dissolved. In addition, the purified CNTs presented a stable homogeneous dispersion in isopropanol solution, implying the presence of functional groups on CNTs that interacted with the isopropanol solvent.Wang, J.-J., Bowden, R.D., Lajtha, K., Washko, S.E., Wurzbacher, S.J., Simpson, M.J., 2019. Long-term nitrogen addition suppresses microbial degradation, enhances soil carbon storage, and alters the molecular composition of soil organic matter. Biogeochemistry 142, 299-313. soil organic carbon (SOC) is one of the largest reservoirs of terrestrial carbon (C) and is a major component of the global C cycle. Yet there is still uncertainty regarding how ecosystems, and the SOC they store, will respond to changes due to anthropogenic processes. Current and future reactive nitrogen (N) deposition to forest soils may alter biogeochemical processes and shift both the quantity and quality of stored SOC. We studied SOC storage and molecular-level composition after 22?years of N additions (100?kg?N?ha?1?y?1) in a temperate deciduous forest. SOC storage in surface soils increased by 0.93?kg?m?2 due to a decline in microbial biomass (phospholipid fatty acids) and litter decomposition. N additions resulted in the selective preservation of a range of plant-derived compounds including steroids, lignin-derived, cutin-derived, and suberin-derived compounds that have anti-microbial properties or are non-preferred microbial substrates. This overall shift in SOC composition suggests limited sustainability and a decline in soil health. The reduction in microbial biomass and increase in specific SOC components demonstrate that long-term N fertilization negatively alters fundamental C cycling in forest soils. This study also demonstrates unequivocally that anthropogenic impacts on?C and N cycling in forests at the molecular-level must be considered more holistically.Wang, J., Cai, C., Li, Y., Hua, M., Wang, J., Yang, H., Zheng, P., Hu, B., 2019. Denitrifying anaerobic methane oxidation: A previously overlooked methane sink in intertidal zone. Environmental Science & Technology 53, 203-212. intertidal zone is an open ecosystem rich in organic matter and plays an important role in global biogeochemical cycles. It was previously considered that methane was mainly removed by sulfate-dependent anaerobic methane oxidation (sulfate–AOM) process in marine ecosystems while other anaerobic methane oxidation processes were ignored. Recent researches have demonstrated that denitrifying anaerobic methane oxidation (DAMO), consisting of nitrite-dependent anaerobic methane oxidation (nitrite–AOM) and nitrate-dependent anaerobic methane oxidation (nitrate–AOM), can also oxidize methane. In this work, the community structure, quantity and potential methane oxidizing rate of DAMO archaea and bacteria in the intertidal zone were studied by high-throughput sequencing, qPCR and stable isotope tracing method. The results showed that nitrate–AOM and nitrite–AOM were both active in the intertidal zone and showed approximate methane oxidation rates. The copy number of 16S rRNA gene of DAMO archaea and DAMO bacteria were 104 ～ 105 copies g–1 (dry sediment), whereas NC10 bacteria were slightly higher. The contribution rate of DAMO process to total anaerobic methane removal in the intertidal zone reached 65.6% ～ 100%, which indicates that DAMO process is an important methane sink in intertidal ecosystem. Laboratory incubations also indicated that DAMO archaea were more sensitive to oxygen and preferred a more anoxic environment. These results help us draw a more complete picture of methane and nitrogen cycles in natural habitats.Wang, K., Xu, Y., Duan, P., Wang, F., Xu, Z.-X., 2019. Thermo-chemical conversion of scrap tire waste to produce gasoline fuel. Waste Management 86, 1-12. hydropyrolysis (CHP) of scrap tire was investigated for production of gasoline fuel. Effects of CHP process variables such as catalysts type ((activated carbon, AC), Ir/C, Rh/C, Pt/C, Ru/C, and Pd/C), temperature (200–450?°C), time (30–120?min), catalyst loading (0–40?wt%), and hydrogen pressure (0.1–12?MPa) on the CHP products distribution and properties of the hydropyrolysis oil (HPO) were examined. Ru/C was identified as the most suitable catalyst in terms of the HPO quality and the catalytic effect predominantly came from the noble metal. Temperature was the most influential factor affecting the yield and quality of the HPO and followed by the order of catalyst loading?>?H2 pressure?>?time. Higher temperature, time, and catalyst loading would decrease the yield of HPO and increase the yield of gaseous product whereas contrary results were observed with increasing the H2 pressure. With added noble metals, the hydrodenitrogenation, hydroSization, and hydrodeoxygenation reactions of the HPO were promoted and greatly lowered N, O, and S contents of the HPO with increasing the temperature, time, catalyst loading, and H2 pressure. The lowest N, O, and S contents of 0.02, 0.41 and 0.41?wt% of HPO were achieved at 430?°C, 60?min, 10?wt% Ru/C, and 12?MPa H2. The higher-heating value of the HPOs varied between 44 and 46?MJ/kg depending on the reaction conditions. More than half of the energy of the ST was converted into the HPO. The HPO mainly consisted of saturated and unsaturated hydrocarbons one to five benzene derivatives. The distillate fraction between 35 and 250?°C of the HPO is more than 80?wt%. Thus, we view that CHP is an alternative way to produce high quality hydro-carbon fuel from scrap tire.Wang, L., Jiang, W.Y., Jiang, D.B., Zou, Y.F., Liu, Y.Y., Zhang, E.L., Hao, Q.Z., Zhang, D.G., Zhang, D.T., Peng, Z.Y., Xu, B., Yang, X.D., Lu, H.Y., 2018. Prolonged heavy snowfall during the Younger Dryas. Journal of Geophysical Research: Atmospheres 123, 13,748-13,762. Snowfall is an important component of Earth's climate system; however, long, continuous high-resolution records of global snowfall are lacking because of the absence of suitable proxies. In this study, diatom record from the sediments of Yunlong Lake, in the southeastern Tibetan Plateau, was used to reconstruct snowfall during the Younger Dryas (YD). Variations in the abundance of low-light-tolerant diatoms and diatom flux indicate that the duration of lake ice cover during the YD was significantly longer than that during the colder Heinrich event 1; this suggests that heavy snowfall, rather than temperatures, was responsible for the greater duration of lake ice cover during the YD. Thus, we conclude that prolonged, heavy snowfall occurred in the southeastern Tibetan Plateau during the YD. In addition, this conclusion is supported by the results of a climate model simulation that also suggest that heavy snowfall occurred at high latitude in the Northern Hemisphere during the YD. We propose that the heavy snowfall intensified cooling in Northern Hemisphere by increasing the albedo and that it increased hydrological variability at low latitudes by increasing the duration of the southward migration of the Intertropical Convergence Zone and by delaying the onset of the Asian summer monsoon. The snowfall would have been a source of continuous freshwater that acted as a positive feedback and resulted in a prolonged weakened state of the Atlantic meridional overturning circulation, which lasted for more than 1,000?years. Overall, our results emphasize the amplification and positive feedback function of heavy snowfall in triggering abrupt climate change.Wang, M., Xie, W., Huang, K., Dai, X., 2019. Fine characterization of lithofacies and pore network structure of continental shale: Case study of the Shuinan Formation in the north Jiaolai Basin, China. Journal of Petroleum Science and Engineering 175, 948-960. is a continuously growing collection of research on continental shale reservoirs. This paper characterizes the Lower Cretaceous Shuinan Formation, a continental shale in the Jiaolai Basin, China, by adopting the improved ternary diagram of carbonate and clay minerals, and argon ion milling-SEM, high-pressure mercury injection, low-temperature N2 adsorption, low-temperature CO2 adsorption and related geochemical experiments. The pore network structure is visually characterized under an electron microscope and indirect quantitative statistics of reservoir space. The influence factors of the full-scale pore development are classified according to the geochemistry and mineral content of different lithofacies within the shale reservoir. The results reveal that, there are five types of shale lithofacies in the Shuinan Formation: siliceous calcareous shale lithofacies (Ca1), calcareous/siliceous mixed shale lithofacies (F2), calcareous siliceous shale lithofacies (Si3), mixed siliceous shale lithofacies (Si2) and argillaceous siliceous shale lithofacies (Si1). The pores are characterized as intergranular pores and intragranular pores, with microcracks dominating the pores. Combined with the results of surface porosity and joint characterization of the pores, the pores within the shale in the Shuinan Formation that would be advantageous for shale gas development are mainly mesopores and macropores, greater than 10?nm in diameter. Pore development is controlled by mineralogy. Brittle minerals are beneficial to the development of micropores, mesopores and macropores, while carbonate minerals are not conducive to the development of pores in general. Filling occurs mainly in pores of 30–50?nm range. Finally, based upon the lithofacies classification, geochemical properties and pore characterization, the most suitable sections of the LC-1 well for shale gas development are concentration in the middle-lower Shuinan Formation.Wang, N., Li, M., Hong, H., Song, D., Tian, X., Liu, P., Fang, R., Chen, G., Wang, M., 2019. Biological sources of sedimentary organic matter in Neoproterozoic–Lower Cambrian shales in the Sichuan Basin (SW China): Evidence from biomarkers and microfossils. Palaeogeography, Palaeoclimatology, Palaeoecology 516, 342-353. of the occurrence and formation of sedimentary organic matter in the Sichuan Basin, southern China, provides valuable insights into the biological sources and compositions of Neoproterozoic to Lower Cambrian shales. Rock samples from two sets of shales in the Sichuan Basin and adjacent areas, including the Ediacaran Doushantuo shale and the Lower Cambrian Qiongzhusi shale in the Gaoshiti-Moxi and Ziyang-Weiyuan areas were collected and geochemically analyzed in this study. The distribution of biomarkers, stable carbon isotope compositions and microfossil characteristics reveal that eukaryotic algae including chlorophytes, pelagophyceae, dinoflagellates, diatoms (or their ancestors) and sponges proliferated widely during the Late Neoproterozoic to Early Cambrian in the Sichuan Basin. Cyanobacteria, some α-Proteobacteria, rhizobiales and aerobic methanotrophs also made a contribution to organic matter in the studied shales. Aerobic methanotrophs that utilize 13C-depleted substrates such as CH4 as carbon sources may have been the cause of anomalous 13C-depleted kerogen in the study area.Wang, R., Sang, S., Jin, J., Zhao, L., Gao, W., Fu, W., Shi, F., Deng, E., 2019. Characteristics and significance of heterogeneity of sea-land transitional facies shale gas reservoir in North Guizhou, China. Geosciences Journal 23, 101-117. order to identify the characteristics of the longitudinal heterogeneity of the sea–land transitional facies shale gas reservoir in the upper Yangtze region of North Guizhou, studies on the lithological combination, rock and mineral composition, geochemical parameters and reservoir microanisotropy characteristics of Longtan Formation in the study area are conducted on the basis of core observation, testing of geochemistry and reservoir physical property and well logging interpretation. The studies show that the lithological assemblages of the Longtan Formation are diverse and form an amina interbedding of “sand-mud-coal” with obvious cyclicity characteristics. There is a large longitudinal difference in rock and mineral composition and the average mass fraction of the clay mineral is 39.83%, which is obviously higher than that of the marine shale in North America and South China; the longitudinal heterogeneity of the organic matter abundance is high, with an average of 2.17% in the upper part, and 4.51% in the lower part; in accordance with the results observed with the scanning electron microscope and results calculated through pore fractal, the microscopic pore heterogeneity of the reservoir is high. The comparison and analysis of connecting wells with different scales in the study area show that the control effect of the depositional environment on longitudinal macroscopic heterogeneity of Longtan Formation is obvious, and the longitudinal microscopic heterogeneity is controlled through diagenesis. Meanwhile, studies with main coal mining seam as the seam section division method conclude that the heterogeneity of Coal Seam Sections 4 to 5 and Coal Seam Sections 13 to 15 is significantly smaller than that in other seam sections, and the Coal Seam Sections 4 to 5 and Coal Seam Sections 13 to 15 can be considered as a priority key seam section during development of shale gas.Wang, Y., Qiu, N., Borjigin, T., Shen, B., Xie, X., Ma, Z., Lu, C., Yang, Y., Yang, L., Cheng, L., Fang, G., Cui, Y., 2019. Integrated assessment of thermal maturity of the Upper Ordovician–Lower Silurian Wufeng–Longmaxi shale in Sichuan Basin, China. Marine and Petroleum Geology 100, 447-465. Wufeng-Longmaxi marine shale of the Upper Ordovician (O3w)-Lower Silurian (S1l) is the main source rock and target for shale gas exploration in Sichuan Basin, China. Maturity assessment is very important for shale gas evaluation, and such assessment is difficult because of the absent of vitrinite, which is the main objective for vitrinite reflectance analysis. Graptolite fragments and solid bitumens are the dominant forms of organic matter in the shales. In this article, optical reflectance analysis of solid bitumen and graptolite and Raman spectroscopy characterization of graptolite were investigated to reduce the levels of uncertainty in thermal maturity assessment. The aims were to (1) build the correlation between graptolite reflectance and solid bitumen reflectance, to (2) establish the relationship between graptolite reflectance and Raman spectroscopy, and (3) to re-build the maturity distribution of such gas shale in Sichuan Basin.32 core samples and 22 outcrop samples have been collected for the optical reflectance analysis, and the mean graptolite random reflectance in Sichuan Basin ranges from 1.21% to 4.91%. The random reflectance of graptolite (GRo) is higher than that of solid bitumen (BRo), and graptolite random reflectance can effectively be used as a maturity indicator. Compared with graptolite maximum reflectance (GRomax), graptolite random reflectance is more precise owing to smaller standard deviation.A natural evolution of maturity series of graptolites have been chosen for Raman spectroscopy analysis. Based on the previous studies of the relationship between Raman spectroscopy and vitrinite reflectance, the correlations between the graptolite random reflectance and vitrinite reflectance (VRo) for over maturity stage were obtained through characteristic of the Raman spectroscopy. The results indicate relationship between GRo and VRo is not a single linear relationship. Through the calculation, the maturities of this gas shale interval range from 1.16% to 3.63%, which provides the basic important information for shale gas evaluation in Sichuan Basin.Wang, Y., Xu, S., Hao, F., Lu, Y., Shu, Z., Yan, D., Lu, Y., 2019. Geochemical and petrographic characteristics of Wufeng-Longmaxi shales, Jiaoshiba area, southwest China: Implications for organic matter differential accumulation. Marine and Petroleum Geology 102, 138-154. organic matter-rich shales in Wufeng-Longmaxi Formation have been considered to be a high-quality source rock and a main shale-gas producer in southern China. As the material basis of shale gas, the organic matter content in shales exhibits a notable vertical difference in the Jiaoshiba area of Fulin shale gas field. This study integrated detailed geochemical analysis and sedimentary observations to investigate organic matter enrichment and depletion mechanism. Three intervals are identified by organic matter contents and their according variations. Six major lithofacies are identified based on mineral composition X-ray diffraction (XRD) analyses, microscopic observations and Focused Ion Beam-Scanning Electron Microscopy (FIB-SEM) data. Geochemical redox proxies (Mo-EF, U-EF, V/Cr and Corg/P) indicate that organic matter-rich shales of Wufeng and bottom Longmaxi formation are deposited in anoxic conditions, whereas organic matter-lean shales of the middle to top Longmaxi formation are deposited in oxic environment. This pattern is influenced by both worldwide marine transgression and regional tectonic movement. The productivity proxies (P/Al, Cu/Al, Ni/Al, SiO2-bio) indicate that the organic matter-rich Wufeng-Longmaxi shales were deposited under moderate to high surficial primary productivity. Increasing terrigenous influxes dominated organic matter dilution and may have been promoted by regional tectonic uplift. The organic matter enrichment or depletion mechanisms in each unit are controlled by different geological events. Enrichment was controlled by multiple reasons, including both global and regional factors, whereas depletion was mainly dominated by regional tectonic uplift. Additionally, the sequence stratigraphic boundaries coincide with organic matter shifting interfaces, indicating that high-resolution sequence stratigraphy of fine-grained sediments may have a certain effect on optimal reservoir predication. Conversely, boundaries of TOC and geochemical proxies may also help to subdivide sequence boundaries.Wang, Y.L., Wang, Q., Yuan, R., Sheng, X.F., He, L.Y., 2018. Isolation and characterization of mineral-dissolving bacteria from different levels of altered mica schist surfaces and the adjacent soil. World Journal of Microbiology and Biotechnology 35, 2. play important role in mineral weathering. However, little is known about rock-associated mineral-dissolving bacteria. In this study, 129 bacterial isolates were obtained from the less and more weathered mica schist surfaces and the adjacent soil and characterized for mineral dissolving activity, population, and the linkage of rock weathering level and distribution of the bacteria. Among the 129 isolates, 112 isolates could dissolve biotite. The relative abundance of the highly effective Fe solubilizers was significantly higher on the more altered rock surface (89.6%) than in the soil (51.2%) and on the less altered rock surface (22.5%), while the relative abundance of the highly effective Si solubilizers was significantly higher in the soil (65.9%) than on the more (41.7%) and less (12.5%) altered rock surfaces. Furthermore, 17.5–42.5%, 87.5%, and 60.9–90.2% of the highly effective acid- and siderophore-producing isolates were obtained in the less and more weathered rocks and the soil, respectively. The mineral-dissolving bacteria belonged to 18 genera and Burkholderia, Bacillus, and Paenibacillus were the dominant and highly effective mineral-dissolving bacteria. Phylogenetic analysis found 2, 9, and 5 bacterial species in the highly effective mineral-dissolving bacteria on the less and more altered rock surfaces and in the soil, respectively. The results showed the abundant and diverse mineral-dissolving bacterial populations on the more weathered rock surfaces. The results also suggested distinct mineral-dissolving activities and mechanisms of the bacteria and highlighted the possibility for the development of bacterial inocula for plant nutrition improvement in silicate mineral-rich soils.Wei, G., Yang, W., Xie, W., Jin, H., Su, N., Sun, A., Shen, J., Hao, C., 2018. Accumulation modes and exploration domains of Sinian-Cambrian natural gas in Sichuan Basin Acta Petrolei Sinica 39, 1317-1327. in Sichuan Basin have good accumulation conditions, multiple exploration domains and huge resources potential of natural gas. In the basin, four sets of source rocks are developed, including high-quality argillaceous rocks in Cambrian Qiongzhusi Formation, Member 3 of Sinian Dengying Formation, Doushantuo Formation, and argillaceous carbonate rocks in Sinian Dengying Formation. Four sets of large-scale reservoirs are developed, including the hill-beach dolomite in Member 4 of Sinian Dengying Formation, the mudstone in Member 3 of Sinian Dengying Formation, the grain-beach dolomite in Lower Cambrian Longwangmiao Formation and the karst dolomite in Middle Cambrian Xixiangchi Formation. Three sets of direct cap rocks are developed, including the mudstones of Member 3 of Dengying Formation and Lower Cambrian Qiongzhusi Formation, and the gypsum-salt rocks of Middle Cambrian Gaotai Formation. All formations show favorable source-reservoir-cap assemblages. The source rocks, reservoirs and cap rocks could form favorable source-seal assemblages. According to different accumulation conditions and the main controlling factors of accumulation in various areas, four Sinian-Cambrian accumulation modes in Sichuan Basin are divided, i.e., the structural-lithologic gas accumulation mode at the platform margins on two sides of the rift, the lithologic gas accumulation mode inside the rift, the structural-lithologic gas accumulation mode inside the platform of central Sichuan and the structural gas accumulation mode in southeast Sichuan Basin. Four exploration domains are evaluated as below:(1)the hill-beach bodies on two sides of the rift are characterized by good reservoir quality and source-reservoir allocation, and the key to exploration is to select the target with stable structure and good preservation condition; (2)karst reservoirs are developed in the isolated hill-beach bodies on both sides of the rift, surrounded by source rocks, and the key to exploration is to elaborate the isolated hill-beach bodies; (3)the reservoirs and source rocks inside the platform of central Sichuan are superimposed on a large scale, characterized by stable structure and decentralized resources, and the key to exploration is to find the enrichment area. (4)the tectonic traps in rows and zones are developed in East and South Sichuan, and the key to exploration is to find well-preserved traps.Wei, X., Hayes, D.J., Fraver, S., Chen, G., 2018. Global pyrogenic carbon production during recent decades has created the potential for a large, long-term sink of atmospheric CO2. Journal of Geophysical Research: Biogeosciences 123, 3682-3696. play an important role in the terrestrial biosphere carbon cycle, not only through direct carbon release but also contributing to a potential long‐term storage as pyrogenic carbon (PyC). PyC is formed through fires, and, because it may resist further biological and chemical degradation, is more stable in soil and sediment than original biomass. At the global scale, contributions of fires to both atmospheric CO2 emissions and PyC accumulation are potentially large but difficult to estimate. Our analysis was based on existing simulation results from two different modeling approaches (Global Fire Emissions Database version 4 [GFED4s] and Terrestrial Ecosystem Model version 6 [TEM6]) that used global area burned data to provide recent, retrospective estimates of CO2 emissions from vegetation combustion, together with published, biome‐ and continental‐scale conversion ratios that relate CO2 emissions to PyC production (PyC/CO2) during combustion. The estimates of global CO2 emissions from fires differed substantially between the two models' results. GFED4s estimated 2,041 Tg C/year during the 2000–2016 time period, whereas the TEM6 estimate was considerably lower at 643 Tg C/year from 2000 to 2010. Global PyC production estimates from fires were 153.4 ± 18.7 and 49.5 ± 4.9 Tg C/year based on the emission estimates from GFED4s and TEM6, respectively. Our results suggest that African tropical savanna fires produced the largest amount of CO2 emissions and PyC among global biomes, the most significant interannual variations in CO2 emissions and PyC production were found in tropical forests, and the magnitude of PyC produced by fires each year represented a potentially significant long‐term sink of atmospheric CO2.Weniger, P., Blumenberg, M., Berglar, K., Ehrhardt, A., Klitzke, P., Krüger, M., Lutz, R., 2019. Origin of near-surface hydrocarbon gases bound in northern Barents Sea sediments. Marine and Petroleum Geology 102, 455-476. the southern part of the Norwegian Barents Sea extensive hydrocarbon exploration and drilling has led to several oil and gas discoveries, yet little is known on the petroleum systems and potential hydrocarbon reservoirs in the northern Norwegian Barents Sea. If hydrocarbons generated by thermogenic processes deep in the subsurface migrate to the surface, traces of these hydrocarbons can remain in the near-surface sediments and provide indirect information on potential petroleum systems. Near-surface hydrocarbon prospecting is a method frequently used in hydrocarbon exploration of frontier areas, where no direct geochemical information from drilling is available. To improve knowledge of subsurface structures and the evolution of potential petroleum systems in the northern Barents Sea, seismic data and near-surface sediment samples were collected. Analysis of bound hydrocarbon gases extracted from these sediments revealed concentrations significantly above background in areas along the Hornsund-Kn?llega Fault Complex as well as near margins of the Olga Basin. Generally, the compositional and stable carbon isotope signatures of bound gases indicate thermogenic origins from source rocks of oil window maturity for near-surface gases with anomalous high concentrations, whereas for sediments with low concentration of bound gases, mixture of thermogenic and microbial gas is indicated. Amount and composition of bound gas extracted from source rock samples from Spitsbergen indicate that contribution of transported material may have influenced the bound gas in near-surface marine sediment of the Barents Sea in areas where presence of mature organic matter is indicated. In the Kn?legga Fault Complex near the western Barents Sea margin high concentrations of thermogenic gas in near-surface sediments are associated with fault-bound basins and most likely originate from the Paleocene-Eocene Torsk Formation. In the Olga Basin higher bound gas concentrations occur near the southern border of the basin corresponding to sub-cropping Late Jurassic – Early Cretaceous shales, whereas elevated concentrations in the northern Olga Basin are associated with reactivated faults, reaching close to the surface. Sediments above the center of the basin show significantly lower bound gas concentrations. These observations indicate that the Jurassic shales act as a regional seal for hydrocarbons and that reactivated faults at the basin margin represent pathways for migration to the surface. 1D basin and petroleum systems modeling for the Olga Basin indicates that Early to Middle Triassic sediments reached oil window maturity and represent the most likely source for thermogenic near-surface gas in that area.West, C., Lemasson, E., Nagai, K., Shibata, T., Franco, P., Bertin, S., Hennig, P., Lesellier, E., 2019. Characterization of novel polymer-based pyridine stationary phases for supercritical fluid chromatography. Chromatographia 82, 143-152. silica is one of the most famous stationary phases employed in supercritical fluid chromatography, especially for the analysis of basic compounds and even without an additive in the mobile phase. In the present paper, we present the synthesis and characterization of three original stationary phases based on poly(vinylpyridine) polymers supported on silica. The position of nitrogen atom relative to the polymer chain was varied to be in the 2, 3, or 4 position. All these phases were prototypes, while the poly(4-vinylpyridine) phase was subsequently commercialized (DCPak P4VP from Daicel Corporation). The stationary phases obtained are characterized in supercritical fluid chromatography with carbon dioxide—methanol mobile phase, with a modified version of the solvation parameter model, to take account of ionic interactions. The three phases are also compared to a 2-ethylpyridine-bonded silica phase and a 2-picolylamine-bonded silica phase. It appears that the polymer-based pyridine phases are significantly more retentive than brush-type pyridine phases and adequately shield residual silanol groups to prevent unwanted interactions with basic compounds. The different selectivities and chromatographic performances are also evidenced with sample applications on pharmaceutical compounds, notably with a selection of 140 drug candidates.Whitehouse, M.J., Dunkley, D.J., Kusiak, M.A., Wilde, S.A., 2019. On the true antiquity of Eoarchean chemofossils – assessing the claim for Earth’s oldest biogenic graphite in the Saglek Block of Labrador. Precambrian Research 323, 70-81. recent claim to have found traces of Earth’s earliest life (>3.95?Ga) utilising isotopically light carbon in graphite-bearing metapelites from the Saglek Block of northern Labrador, Canada, is re-evaluated applying rigorous geological and geochronological criteria. The establishment of these criteria in previous evaluations of early life claims from southern West Greenland and northern Canada is reviewed in order to provide a backdrop to discussion of the Saglek claim. In particular, we emphasise the importance of the scale of lithological continuity in determining the veracity of such claims, which are considerably easier to demonstrate from large, relatively less tectonised supracrustal remnants like the Isua Greenstone Belt than they are from smaller, isolated enclaves of the kind found on Akilia or the highly tectonised and imbricated unit that is found in the Saglek Block. Unambiguous field relationships between ca. 3.9?Ga tonalitic gneiss and the graphite-bearing metasediments have not been demonstrated in the literature that the Saglek claim relies upon, and earlier U-Pb-Hf isotopic studies on zircon from metasediments at one of the localities used in the claim indicate a Mesoarchean to Neoarchean time of deposition. We conclude that, irrespective of the validity of the carbon isotopic evidence, field relationships and geochronological evidence fail to demonstrate an age of >3.95?Ga for the potential traces of life.Wolfender, J.-L., Nuzillard, J.-M., van der Hooft, J.J.J., Renault, J.-H., Bertrand, S., 2019. Accelerating metabolite identification in natural product research: Toward an ideal combination of liquid chromatography–high-resolution tandem mass spectrometry and NMR profiling, in silico databases, and chemometrics. Analytical Chemistry 91, 704-742. product research aims to characterize specialized metabolites from various living organisms and assess their biological properties from either a chemical ecology or drug discovery viewpoint. These “specialized” metabolites, which are oftentimes referred to as “secondary metabolites”, are nonessential to sustain the life of a given organism but necessary for its survival in a given environment, in contrast to “primary metabolites”, including amino acids, lipids, and carbohydrates, which are necessary for physiology purposes.(1) Specialized metabolites are small-molecular-weight molecules (typically <1500 Da) mainly involved in processes like defense against other biotic as well as abiotic agents or used as attractants for reproduction purposes due to the sessile lifestyles of many organisms, such as plants and microorganisms.(2) Throughout this review, we will refer to such metabolites as natural products (NPs).NPs from all living organisms have evolved and diversified for increased fitness within a specific environment. This has resulted in plants and microorganisms achieving the synthesis of distinct sets of NPs. Such pressure of evolution has generated the huge chemodiversity of NPs in nature. In plants, for example, and as stated by Pichersky and Lewinsohn, the total number of NPs found in the kingdom by far exceeds the capacity of any one plant genome to encode the necessary enzymes, and just as a plant lineage acquires the ability to elaborate new specialized compounds during evolution, it also loses the ability to produce others.(2)NPs thus include a large and diverse group of compounds from a variety of sources, mainly plants, bacteria, and fungi, from terrestrial and aquatic biotopes. They play significant biological roles in all organisms and have evolved to interact with enzymes, receptors, and ion channels. Some are active in living cells and are able to cross cell membranes and interfere with enzymes or even act against parasites.(3) Due to their coevolution in natural systems, NPs are therefore encoded to be bioactive and of high interest in the drug discovery field. They have long been used as medicines, and today, they continue to be a reservoir of potential drugs.(3,4) Thus, NPs and their related structures serve as essential sources of new chemical entities for the pharmaceutical industry due to their immense variety of functionally relevant compounds.(5)The chemical space encompassed by NPs is very large,(6) and more than 250?000 NPs have been reported to date in the dictionary of natural products (DNP).(7) The DNP surveys literature data of all NPs characterized worldwide as the result of the isolation work and full de novo identification of varied organisms with their taxonomic origin.(7) It is important to note that the DNP mainly focuses on plant resources, implying that when the microbial chemical space is added, the number above can easily quadruple. The chemical space is characterized by a “multidimensional descriptor space” in which NPs can be associated with a wide range of “descriptors” and “properties”, such as their molecular mass, lipophily (their affinity for a lipidic environment), compound class, and the topological features of their molecular structure.(8) A measurement of the chemodiversity of NPs can be obtained by evaluating the size of the chemical space visualized by the principal component analysis (PCA) of sets of molecular descriptors. This space has been shown to be much larger for NPs than those occupied by new chemical entities coming from combinatorial chemistry.(9) Both drugs and NPs cover similar parts of chemical space, demonstrating the potential of many NPs to become leads for drug discovery.(10) The methods used to navigate this chemodiversity space have constantly evolved. For example, ChemGPS-NP assists in compound selection and prioritization, property description and interpretation, cluster analysis and neighborhood mapping, as well as the comparison and characterization of large compound data sets.(11)Notwithstanding the potential of NPs to become effective drugs, the drug discovery workflow that leads from crude natural extracts to well-characterized bioactive NPs as hits and then as lead compounds is considered complex, slow, costly, and often not compatible with the pace of high-throughput screening campaigns. This explains in part why many pharmaceutical industries slowed down and then terminated most of their NP-oriented research programs in the early 2000s.(3,12)This difficulty of working with NPs is in part related to the very high complexity of the biological matrixes (natural crude extracts) in which they are embedded, which in turn causes their chemical richness. NPs as pure active ingredients are typically extracted from plants and microorganisms with solvents of different polarities (usually hydroalcoholic mixtures, methanol, ethyl acetate, or methylene chloride). Each of these extracts typically contains tens of main NPs and hundreds or thousands of less abundant ones. In addition, polar extracts are dominated by primary metabolites, mainly saccharides, and lipophilic extracts are dominated by various types of lipids and pigments. These compounds are part of the metabolome but are often not of interest for bioactivity. There are, however, exceptions; for example, polysaccharides are known to exhibit immunostimulating effects(13) and the high number that are bioactive, suggesting their functional roles.(14) Potentially all NPs, even minor constituents, may have interesting biological properties (e.g., potent defense toxins, hormones). Their identification requires using metabolite profiling methods that are able to work over a large dynamic range and generate information-rich spectral data for their full or partial identification.(15)The identification of bioactive NPs from such complex matrixes is classically performed in pharmacognosy (search for bioactive compounds from natural sources) by bioactivity-guided isolation approaches. Here, crude extracts exhibiting given biological activity are fractionated by a combination of preparative chromatographic methods. All fractions are submitted to bioassays, and those fractions continuing to exhibit activity are carried through further isolation and purification steps until pure active ingredients are obtained. These ingredients are then fully characterized by a combination of nuclear magnetic resonance spectroscopy (NMR), high-resolution mass spectrometry (HRMS), and chiroptical spectroscopic methods (i.e., sensitive to molecular chirality, such as electronic circular dichroism (ECD) and vibrational circular dichroism (VCD)) until their structure and absolute configuration are obtained.(16) This process is slow but effective and has led to major breakthroughs in NP research, such as the discovery of artemisinin (a sesquiterpene lactone containing an unusual peroxide) isolated from Artemisia annua. Artemisinin has become a reference drug for the treatment of malaria, and its discovery by Professor Tu Youyou led her to be awarded the Nobel Prize of Medicine in 2015.(17)To rationalize the process that yields interesting active ingredients, the metabolite profiling of crude extracts and dereplication prior to isolation has been underway for years in classical NP research.(18) Dereplication is the process of differentiating novel compounds from those that have already been studied.(12,19) Since its appearance in 1990, dereplication has significantly evolved over the last decades. It has been used in different workflows ranging from major compound identification and the acceleration of activity-guided fractionation up to the chemical profiling of collections of extracts.(18)In parallel to these advances in metabolite profiling, the field of metabolomics appeared at the beginning of the millennium for life science applications(20) and experienced exponential growth until today, as is the case for other omics approaches. Metabolomics is defined as a nonselective, universally applicable, comprehensive analytical approach for the identification and quantitation of metabolites in a biological system. This area of research strives to obtain complete metabolite fingerprints, detect differences between metabolites, and generate hypotheses to explain these differences.(19) Metabolomics is practically considered the large-scale analysis of metabolites of a given organism during various physiological states,(21) but it also extends to the comparative comprehensive metabolite profiling for deep/full metabolome analyses for chemotaxonomic investigations and NP prioritization studies in drug discovery. Tools in metabolomics have tremendously evolved over the past decade because such an unbiased data-driven approach has served many fields of life sciences and has also strongly influenced various aspects of NP research, notably in giving additional dimensions to dereplication. These developments were partly driven by the progress made in the acquisition techniques for metabolite profiling in complex biological matrixes in both the MS and NMR fields in terms of sensitivity, resolution, and throughput but also more recently by the introduction of in silico and chemometric associated methods.(22) It was recognized that traditional analysis methods only slightly dipped into the complete pool of molecules present in complex mixtures, thereby leaving a large amount of “dark matter.”(23) These unknowns potentially represent much-needed novel bioactive molecules that could, for example, be used to combat antibiotic resistance.In metabolomics, putative or partial metabolite identification from metabolite profiles or fingerprints of complex extracts is referred to as “annotation”. Today, this process still represents a major bottleneck in metabolomics because annotation is often not unambiguous, and only putative or partial assignments can be made. When compared to biological fluid metabolomics, this aspect is even more striking in NP research because NP chemodiversity is very extensive, and sample compositions vary substantially based on the organisms that are screened. In contrast, in biological fluid analysis, redundant metabolites are often profiled, and in this case, quantitation aspects are key to observing sometimes minute but significant changes in profiles (e.g., those related to disease or diet changes).To assess the level of confidence of metabolite annotation, different reporting standards for identification have been defined by metabolomics researchers. This resulted in a four-level system ranging from Level 1 (identified compound) via Levels 2 and 3 (putatively annotated compounds and compound classes) to Level 4 (unidentified or unclassified metabolites that can be differentiated based on analytical data, see Quality of Reporting of Metabolite IDs).(24)In typical NP research, unknown metabolites must be fully characterized de novo after isolation.(25) This also occurs redundantly for known NPs when the dereplication process is not sufficiently efficient. The additional full assessment of their absolute configuration by chiroptical methods and sometimes X-ray crystallography is also often required because 3D structural characterization is key to understanding ligand–target interactions in pharmacological investigations of NPs.(26)Full characterization clearly provides the high-quality unambiguous identification of metabolites but is time-consuming and often not worth the effort, especially when known compounds are redundantly characterized and their spectroscopy data have been published several times. Moreover, the isolation and full identification of minor compounds requires large amounts of biological material. Additionally, the pace of this work is not compatible with the pace at which high-throughput screening (HTS) campaigns are performed on extracts for drug discovery purposes.(3)The rapid high-quality identification of NPs is not only necessary for rationally characterizing active ingredients but also increasingly needed for obtaining detailed exhaustive composition information for herbal products used in traditional medicine, nutraceutical products, or botanicals with claimed clinical efficacy.(27) This can facilitate linking composition with possible efficacy, screening for possible toxic NPs, and establishing composition trends for given therapeutic usage in evidence-based approaches.(28) It is also needed to support quality control studies that increasingly rely on fingerprints rather than on single marker determination for herbal products.(29) This need for accurate composition determination is even more complex when studying drugs used by traditional Chinese medicine (TCM), where multiherb preparations are often used.(30)Altogether, only a few “complete” workflows exist that can take the researcher from raw data to performing the robust annotations and identifications of metabolites in complex mixtures; in particular, when investigating completely novel bioresources, existing tools often fail to identify reliable candidate molecules. Moreover, their usage is not always straightforward for NP researchers, which hampers their interpretation of downstream results. Thus, there is a strong need for metabolite profiling methods and data mining workflows that provide a much higher confidence of NP identification with reliable annotation scores that can be achieved with a high degree of automation.In this review, we will describe state-of-the-art metabolite profiling and data analysis methods based on both liquid chromatography (LC)–MS and NMR profiling that are currently used in NP research and metabolomics or related fields or can be implemented. In particular, their coverage in terms of full metabolome analysis will be discussed; however, this review will focus on the structure elucidation of NPs from complex mixtures. The present spectral NMR and MS/MS databases (DBs) suitable for NP annotation will be surveyed together with the different tools that can be used to generate searchable spectra generated in silico from structural NP DBs. Various recent workflows that can lead to annotation will be described and assessed, especially in terms of their usage/implementation in NP research and their ease of operation and level of automation for natural product chemists. Because both MS and NMR data are important for the characterization of NPs, their corresponding dereplication workflows will be treated equally. Current approaches integrating both MS and NMR analytical dimensions will be highlighted, and ideas for progress that can be made for better practical integration will be provided. Future prospects that may also come from the addition of orthogonal methods to LC–MS, such as collisional cross section (CCS) obtained with ion mobility measurements or retention time (RT) predictions, will be put in perspective. Finally, we will share our views on the development that is needed in terms of the contextualization (e.g., taxonomical data) of the metabolomics data generated from NP extracts. The creation of a novel method to combine scores from different and, if possible, orthogonal spectral/physicochemical information for more reliable annotation and the expansion of in silico candidate DBs through predictions of structural variation by exploiting knowledge of natural biosynthesis pathways will also be discussed. We will end by presenting our views and recommendations on the most important and exciting avenues toward more efficient and automated large-scale metabolite annotation and identification workflows.Wood, D.A., 2019. Microbial improved and enhanced oil recovery (MIEOR): Review of a set of technologies diversifying their applications. Advances in Geo-Energy Research 3, 122-140. improved and enhanced oil recovery (MIEOR) deploys microbes into wellbores and subsurface oil reservoirs and/or stimulates in-situ microbes to generate biochemicals that induce positive changes to reservoir and/or fluid conditions. MIEOR has a history of laboratory testing and field trials stretching back many decades, but few large-scale commercial projects. This review describes mechanism and components involved and the challenges in scaling-up laboratory performance to field-wide commercial applications. Microbes tend to exist in consortia with the ability to generate a wide range of biochemicals and biomass capable of performing various useful MIEOR actions and some actions that are detrimental (e.g., reservoir souring, facilities corrosion, formation damage). The complexity of the microbial consortia makes it difficult to unravel the net consequences of growing a microbial community in a specific reservoir. This requires extensive experimental studies coupled with long-term field trials and the outcomes of several recent examples are provided. These complexities and requirements have historically slowed down the commercialization of MIEOR. Significant advances in recent years have provided improved modelling and simulation tools capable of representing more realistically the evolution of MIEOR actions at the micro and macro scales. The advantages and disadvantages of MIEOR are identified and explored. Future expectations for the development and exploitation of MIEOR technologies are discussed considering the recent advances it has achieved.W?rmer, L., Wendt, J., Alfken, S., Wang, J.-X., Elvert, M., Heuer, V.B., Hinrichs, K.-U., 2019. Towards multiproxy, ultra-high resolution molecular stratigraphy: enabling laser-induced mass spectrometry imaging of diverse molecular biomarkers in sediments. Organic Geochemistry 127, 136-145. spectrometry imaging (MSI) collects mass spectra of organic compounds from individual micrometer-sized spots and yields high-resolution images of the spatial distribution of target analytes on sample surfaces. MSI can potentially open a new avenue to ultra-high resolution molecular stratigraphy by resolving the fine-scale distribution of molecular biomarkers in geological records. However, ionization of organic molecules within their sediment matrix remains a critical challenge. Building on the recent introduction of MSI of archaeal tetraether lipids, we have extended the analytical spectrum to additional biomarkers and provide guidelines for the generation of multiproxy, ultra-high resolution paleoenvironmental records. We evaluated the addition of artificial matrices to promote ionization, defined the most suitable MS settings, and increased analytical complexity from pure compounds to their investigation in sediment. Most compounds relevant to molecular stratigraphy are not properly ionized in the presence of conventional matrices, but require atypical ones, such as those based on carbon or silver. Sediments serve as a natural matrix, directly allowing detection of many of these compounds. However, the sediment matrix also inhibits some reactions that otherwise promote detection, such as derivatization of alkenones or silver-mediated ionization of n-alkanes. The robustness of MSI-based molecular stratigraphy is enhanced by analysis of target compounds in narrow m/z ranges, and by summation of mass spectra from several coeval measurement spots. We present an initial inventory of compounds readily detected in the sediment tested, including long chain alkenones and diols, sterols, and pigments, and provide an outlook into the use of MSI in multiproxy studies.Wu, F.P., Yan, J., Zhao, Y.P., Fan, X., Wang, R.Y., Wei, X.Y., 2019. Solubility and molecular composition of organic species in low-rank coals during sequential thermal dissolution in cyclohexane and methanol. Energy Sources, Part A: Recovery, Utilization, and Environmental Effects 41, 1132-1139. this study, six low-rank coals (LRCs) including two lignite samples and four subbituminous coals were sequentially dissolved in cyclohexane and methanol. The yields of cyclohexane-soluble portions?(SPs) from the lignite are slightly lower than those from the subbituminous coals, while the yields of methanol?SPs showed a linear correlation with the oxygen content and O/C ratio. The concentrations of n-alkanes and polycyclic aromatic hydrocarbons in the SPs of subbituminous coals are higher than those of the lignite, and the concentrations of phenols in the SPs are possibly associated with the content of aryl ether bonds in the LRCs.Wu, J., Liang, C., Hu, Z., Yang, R., Xie, J., Wang, R., Zhao, J., 2019. Sedimentation mechanisms and enrichment of organic matter in the Ordovician Wufeng Formation-Silurian Longmaxi Formation in the Sichuan Basin. Marine and Petroleum Geology 101, 556-565. large, typical, marine, organic-rich shale is developed in the Ordovician Wufeng Formation-Silurian Longmaxi Formation in the Sichuan Basin, China, which has rich shale gas resources. This paper uses this type of shale as an example to analyze the influence of the depositional environment on the enrichment mechanisms and sedimentary processes of its organic matter (OM). Based on thin sections and field emission scanning electron microscope observations from well core samples, along with X-ray diffraction and geochemical analysis, the mineralogy, organic and inorganic geochemistry characteristics, as well as the lithofacies, are analyzed. The results show that the shale is mainly composed of quartz and clay minerals but also contains calcite, feldspar, pyrite, etc. The OM includes solid bitumen, algae, graptolite, spongy spicule, radiolarians, etc. The total organic carbon (TOC) content ranges between 0.5% and 6.17%, with an average value of 2.5%. Based on the mineral compositions, the TOC content and sedimentary structure, five kinds of lithofacies are identified. According to the primary productivity, redox conditions, paleosalinity and sedimentation rate characteristics, the formation's sedimentary environment is divided into five intervals. During the OM enrichment processes, the primary productivity, sedimentation rate and redox conditions affect the generation, accumulation and preservation of OM. There is a good positive correlation between primary productivity and TOC content, as well as the redox condition. Sedimentation rate is inversely proportional to TOC content. The change and evolution of the sedimentary environment over these five intervals form different OM occurrence characteristics and associations with lithofacies. Based on the characteristics of OM, lithofacies and the sedimentary environment, as well as the geological background of the study area, the mode of OM occurrence and enrichment was proposed.Wu, K., Lee, T.-H., Chen, Y.-L., Wang, Y.-S., Wang, P.-H., Yu, C.-P., Chu, K.-H., Chiang, Y.-R., 2019. Metabolites involved in aerobic degradation of the A and B rings of estrogen. Applied and Environmental Microbiology 85, Article e02223-18.: Various bacteria, mainly actinobacteria and proteobacteria, are capable of aerobic estrogen degradation. In a previous study, we used the obligate aerobic alphaproteobacterium Sphingomonas sp. strain KC8 as a model microorganism to identify the initial metabolites involved in the oxygenolytic cleavage of the estrogen A ring: 4-hydroxyestrone, a meta-cleavage product, and a dead-end product pyridinestrone acid. In this study, we identified the downstream metabolites of this aerobic degradation pathway using ultraperformance liquid chromatography–high-resolution mass spectrometry (UPLC-HRMS). 4-Norestrogen-5(10)-en-3-oyl-coenzyme A and its closely related deconjugated (non-coenzyme A [non-CoA]) structure, 4-norestrogenic acid, were detected in the estrone-grown strain KC8 cultures. The structure of 4-norestrogenic acid was elucidated using nuclear magnetic resonance (NMR) spectroscopy. The extracellular distribution and the accumulation of 4-norestrogenic acid in the bacterial cultures indicate that the estrogen-degrading bacteria cannot degrade this deconjugated product. We also observed temporal accumulation and subsequent consumption of a common steroid metabolite, 3aα-H-4α(3′-propanoate)-7aβ-methylhexahydro-1,5-indanedione (HIP), in the bacterial cultures. The metabolite profile and genomic analyses shed light on the biochemical mechanisms involved in the degradation of the A and B rings of natural estrogens. In this proposed aerobic pathway, C-4 of the meta-cleavage product is removed by a 2-oxoacid oxidoreductase through oxidative decarboxylation to produce the 4-norestrogen-5(10)-en-3-oyl-CoA. Subsequently, the B ring is cleaved by hydrolysis. The resulting A/B-ring-cleaved product is transformed into a common steroid metabolite HIP through β-oxidation reactions. Accordingly, the A and B rings of different steroids are degraded through at least three peripheral pathways, which converge at HIP, and HIP is then degraded through a common central pathway.Importance: Estrogens, often detected in surface waters worldwide, have been classified as endocrine disrupting chemicals and carcinogens. Bacterial degradation is crucial for removing natural estrogens from natural and engineered ecosystems; however, current knowledge regarding the biochemical mechanisms and catabolic enzymes involved in estrogen biodegradation is very limited. Our estrogen metabolite profile and genomic analyses on estrone-degrading bacteria enabled us to characterize the aerobic estrogen degradation pathway. The results greatly expand our understanding of microbial steroid degradation. In addition, the characteristic metabolites, dead-end products, and degradation genes can be used as biomarkers to investigate the fate and biodegradation potential of estrogens in the environment.Wu, M.-L., Chen, T.-Y., Chen, W.-J., Fahad Baig, M.M., Wu, Y.-C., Chen, Y.-C., 2019. Carbon fiber ionization mass spectrometry coupled with solid phase microextraction for analysis of benzo[a]pyrene. Analytica Chimica Acta 1049, 133-140. phase micro-extraction (SPME) is an effective technique that can be used to selectively enrich trace analytes of interest from complex samples. Owing to its high sensitivity and high selectivity, mass spectrometry (MS) has been widely used as the detection tool to confirm the analytes enriched on SPME fibers. Generally, thermal desorption or solvent desorption is used to desorb analytes from SPME fibers for MS analysis. A straightforward ionization method called carbon fiber ionization (CFI), which uses a single carbon fiber (diameter: ～10?μm) as ionization emitter in MS, has been demonstrated lately. Analytes adsorbed on the carbon fiber, which is placed close (～5?mm) to the inlet of a mass spectrometer, can be readily ionized through corona discharge and detected by the mass spectrometer. One unique feature regarding this approach over other existing ambient ionization methods is that no additional electric contact is applied directly on the carbon fiber. Nevertheless, on the basis of the electric field provided by the mass spectrometer, corona discharge can readily occur for ionizing analytes on the carbon fiber. Carbon fiber has high affinity toward polycyclic aromatic hydrocarbons due to its graphite-like surface structure. We herein explore a hyphenated-technique by combining carbon-fiber based SPME with CFI-MS for extraction of benzo[a]pyrene (BaP), a carcinogen, from aqueous samples. After BaP are adsorbed on a carbon fiber through SPME, the SPME carbon fiber can be readily placed in front of the mass spectrometer for MS analysis. The ions at m/z 252 derived from BaP adsorbed on the carbon fiber can be immediately acquired by the mass spectrometer without the requirement of applying heating or solvent. The limit of detection of BaP using the developed method was as low as ～60 pM. It is also feasible to detect BaP from complex serum sample. The feasibility of using the approach for quantitative analysis of BaP was also demonstrated. The linear dynamic range toward BaP was 0.2–5?nM. The extraction efficiency using this approach for aqueous samples was ～91%.Wu, S., Yang, Z., Zhai, X., Cui, J., Bai, L., Pan, S., Cui, J., 2019. An experimental study of organic matter, minerals and porosity evolution in shales within high-temperature and high-pressure constraints. Marine and Petroleum Geology 102, 377-390. development and evolution of porosity in organic-rich shales (ORSs) is critical to the commercial exploitation of shale oil and gas resources. In this paper, we present the results of high-temperature and high-pressure experiments on typical marine and lacustrine shales to investigate porosity changes. The samples were taken from the Proterozoic Xiamaling Formation in the North China Platform, the Permian Lucaogou Formation in the Junggar Basin, the Triassic Chang 7 member in the Ordos Basin, and the Silurian Longmaxi Formation in the Sichuan Basin, all in China. We found that the key factors influencing porosity evolution include the extent of compaction, abundance of organic matter, degree of thermal evolution, and organic matter–inorganic mineral framework. The effects of thermal evolution on the pore structure of high-mature shales are more obvious than those on low-mature shales. Although the porosity evolution is positively correlated with maturity, we found evidence for different porosity evolution in ORSs in the oil window. High-resolution scanning electron microscopy observations of experimental and actual core samples indicate that liquid hydrocarbon is adsorbed and dissolved in organic matter in the oil window, leading to swelling of the organic material. This explains why there are few organic matter pores in lacustrine shales in China. The pore structure evolution is similar for marine and lacustrine shales, suggesting that kerogen has a stronger influence on the porosity evolution of shale than does the depositional environment. The lower limit of vitrinite reflectance values (Ro) at which abundant organic pores develop is 1.5%–2.5%, and the degree of pore development in ORSs is highest when Ro values are 2.5%–3.0%. These results have important implications for shale oil and gas exploration.Xi, Z., Tang, S., Li, J., Zhang, Z., Xiao, H., 2019. Pore characterization and the controls of organic matter and quartz on pore structure: Case study of the Niutitang Formation of northern Guizhou Province, South China. Journal of Natural Gas Science and Engineering 61, 18-31. and organic matter (OM) are two important components in marine shales that have significant effects on shale gas reservoir quality, particularly on pore structure. However, a limited number of in-depth studies exist on characterizing the OM and quartz. In this study, types of quartz and OM in the organic-rich marine Niutitang shales and their impacts on pore structure were investigated using X-ray diffraction analysis, scanning electron microscopy, nitrogen adsorption, and geochemical analyses. Three OM types (scattered OM, stripped OM, and interstitial OM), four types of OM pores (primary OM pores, convoluted OM pores, shrinkage OM pores, and thermogenic OM pores) and two quartz types (detrital quartz and authigenic quartz) were identified. The Lower Member (LM) and Upper Member (UM) of the Niutitang Formation have different types of OM and quartz, resulting in the differences of pore structure characteristics. Scattered OM and convoluted OM pores and extrabasinal detrital quartz are widespread in the UM, whereas interstitial OM and thermogenic OM pores and authigenic quartz are common in the LM. Quartz in the LM shales positively correlated with TOC, as well as TOC positively correlating with excess-Si, which may indicate that quartz may be mostly biogenic in origin. The biogenic authigenic quartz can act as a rigid framework, which can resist compaction and preserve the internal pore structure and provide enough space to be in-filled by OM. Abundant OM filled inter-particle pores formed by authigenic quartz is the principal matrix for OM pore development. There are positive correlations among TOC and quartz with pore structure parameters and shale with higher contents of TOC and quartz lead to preservation of some primary pores and development of OM pores, indicating that the pore structure in the Niutitang shale may be mainly controlled by OM and quartz. This study suggests that the shale in the LM would more likely contain better pore systems and provide favorable reservoir spaces for shale gas due to its high content and favorable types of OM and quartz.Xia, X., Gao, Y., 2019. Kinetic clumped isotope fractionation during the thermal generation and hydrogen exchange of methane. Geochimica et Cosmochimica Acta 248, 252-273. work investigated the kinetic fractionation of clumped isotopes (13CH3D and 12CH2D2) during thethermal generation and hydrogen exchange of methane. Kinetic reaction networks involving the five most abundant isotopologues of methane are applied. Hydrogen isotope exchange is modeled with a chain reaction network constrained by thermodynamic parameters of methane isotopologues. Analytical solutions under isothermal conditions are obtained for isotope fractionations during methane generation.Both methane generation and isotope exchange are possible to result in “anticlumping” at low conversions and clumped isotope reversal at high conversions. Sensitivity of anticlumping to 13C and deuterium kinetic isotope effects (KIEs) are tested for methane generation. D-D clumping is found to be sensitive to the deuterium KIE of the capping hydrogen, especially when the quantum tunneling effect is present.Clumped isotopic compositions of methane in natural gas accumulations are affected by multiple geochemical and geological factors. Precursor methyl groups are expected to be enriched in clumped isotopes, and the enrichment results in clumped isotopic compositions more positive than the equilibrated ones at the beginning of methane generation. In the oil window to early gas window, clumped isotopes deplete with thermal maturity due to combinatorial anticlumping and gas expulsion. These two factors may bring about clumped isotopic compositions more negative than the equilibrated values. In late wet gas to dry gas window (the same range of ethane and propane decomposition), C-H bonds of methane are activated, and isotope exchange occurs through free radical reactions; as a result, clumped isotopes eventually approach equilibrium. Clumped isotopic composition of methane records the chemical, thermal and flow histories of its source rock, rather than merely the temperature state of a gas accumulation.Xiao, X., Zeng, Q., Zhang, R., Jiao, N., 2018. Prochlorococcus viruses—From biodiversity to biogeochemical cycles. Science China Earth Sciences 61, 1728-1736. the dominant primary producer in oligotrophic oceans, the unicellular picocyanobacterium Prochlorococcus is the smallest and most abundant photosynthetic phytoplankton in the world and plays an important role in marine carbon cycling. Cyanophages that infect Prochlorococcus influence the growth, carbon fixation, diversity, evolution, and environmental adaptation of their hosts. Here, we review studies on the isolation, genomics, and phylogenetic diversity of Prochlorococcus viruses and their interactions with Prochlorococcus. We also review the potential effects of Prochlorococcus viruses on biogeochemical cycling in the ocean.Xie, F., Dai, Z., Zhu, Y., Li, G., Li, H., He, Z., Geng, S., Wu, F., 2019. Adsorption of phosphate by sediments in a eutrophic lake: Isotherms, kinetics, thermodynamics and the influence of dissolved organic matter. Colloids and Surfaces A: Physicochemical and Engineering Aspects 562, 16-25. and desorption of phosphorus (P) at sediment-water interface is one of the key processes of biogeochemical cycling of P in lakes. Thus, adsorption of phosphate by sediments from Lake Dianchi, a eutrophic lake, was investigated in this study. Importantly, the influence of dissolved organic matter (DOM) with fulvic acid (FA) as a representative example on these processes was further studied. The results showed that the presence of FA in the solution did not change the tendency of phosphate adsorption by sediments from Lake Dianchi. Compared with Freundlich equation, Langmuir model fitted better in describing the adsorption isotherms. And the pseudo-second-order kinetic model predicated well the adsorption kinetics for adsorption of phosphate by sediments. Under low concentrations of phosphate, FA promoted desorption of phosphate adsorbed on the sediments. However, adsorption behaviors including capacity and efficiency would be enhanced by presence of FA under high concentrations of phosphate. Based on adsorption thermodynamics, temperature and DOM (FA in this study) were two most important factors for adsorption of phosphate by sediments. Adsorption of phosphate on sediments was a spontaneous endothermic reaction process, which was a chemical-physical process rather than a simple physical adsorption. The influence of FA on the adsorption of phosphate by sediments was closely related with characteristics of sediments such as contents of Fe-Al oxides and organic matter. Aggressive results showed that increasing DOM due to algal blooming was likely an important way for dominant algae to maintain the nutrients such as P in lakes.Xiong, Y., Jin, L., Li, Y., Zhou, Y., Hu, H., 2019. Structural features and pyrolysis behaviors of extracts from microwave-assisted extraction of a low-rank coal with different solvents. Energy & Fuels 33, 106-114. extraction (MAE) of a low-rank Naomaohu (NMH) coal was conducted with two solvents, cyclohexanone (CYC) and tetrahydrofuran (THF), to obtain extracts (ECYC and ETHF) and residues (RCYC and RTHF). The parent coal, extract, and residue were characterized by ultimate analysis, TG, FTIR, GPC, 1H NMR, and solid-state 13C NMR. The results showed that MAE process is more efficient than Soxhlet extraction. The solvent CYC exhibits a higher total extract yield of 8.3 wt % than THF, being 4.7 wt %, during MAE and more efficiency in extracting organic components of NMH coal, especially condensed arenes and macromolecular compounds. The average molecular weight of ECYC is higher than that of average aromatic cluster of NMH coal. Online pyrolysis–vacuum ultraviolet photoionization mass spectrometry was taken to determine the initial pyrolysis products of parent coal, RCYC, and ECYC. The distribution of initial pyrolysis products suggested that NMH coal and ECYC possess similar basic arene structures and ECYC is rich in macromolecular clusters with lots of side chains and bridge bonds. The chemical structure of ECYC could reflect the macromolecular network structure of NMH coal to some extent. This could be an effective method to understand the organic structure of coal.Xu, H., George, S.C., Hou, D., 2019. Algal-derived polycyclic aromatic hydrocarbons in Paleogene lacustrine sediments from the Dongying Depression, Bohai Bay Basin, China. Marine and Petroleum Geology 102, 402-425. sources and origins of polycyclic aromatic hydrocarbons (PAHs) in thirty eight Paleogene organic-rich shales and mudstones from the Shahejie Formation in the Dongying Depression, Bohai Bay Basin have been assessed. Phenanthrene, retene, cadalene, fluoranthene, pyrene, benz[a]anthracene, triphenylene, chrysene, benzofluoranthenes, benzo[e]pyrene, benzo[a]pyrene, indeno[1,2,3-cd]pyrene, benzo[ghi]perylene and coronene were identified in the sediments. The symmetrical 4-ring triphenylene was unequivocally identified by comparison with mass spectra and a synthetic standard. Key PAH ratios including fluoranthene/(fluoranthene?+?pyrene), benzo[a]anthracene/(benz[a]anthracene?+?chrysene), indeno[1,2,3-cd]pyrene/(indeno[1,2,3-cd]pyrene?+?benzo[ghi]perylene) and benzofluoranthene/(benzofluoranthene?+?benzo[e]pyrene) indicate a mainly diagenetic/catagenetic origin for the PAHs. The relative low abundance of the 6-ring indeno[1,2,3-cd]pyrene and benzo[ghi]perylene and the 7-ring coronene suggest the absence of larger, high temperature wildfires, either due to inadequate seasonality of the humid-arid climate, or limited terrigenous organic matter input. Phenanthrene and alkylphenanthrenes are likely derived from phytoplankton, based on the correlation of the relative abundance of C27 regular steranes and 1-methylphenanthrene and 9-methylphenanthrene. The methylphenanthrenes, triphenylene, alkyltriphenylenes and benzo[e]pyrene may share a common source as their occurrences are closely correlated. Four groups of samples were differentiated on the basis of the relative abundance and distribution patterns of benz[a]anthracene, triphenylene and chrysene, showing that these compounds are useful PAH markers in petroleum geochemistry. Thermal maturation effects are the major control on the relative abundance and distribution of the non-combustion derived PAHs (e.g. biphenyl, fluorene, fluoranthene, pyrene, benz[a]anthracene, triphenylene) in lacustrine sediments. Benz[a]anthracene decreases in relative abundance while triphenylene increases in relative abundance with burial depth. Correlation of the newly defined triphenylene-chrysene ratio (TCR; triphenylene/(triphenylene?+?chrysene) with burial depth and biomarker maturity parameters was observed, suggesting that it may be a useful maturity indicator for lacustrine oils and sediments in the Dongying Depression.Xu, H., Sang, S., Yang, J., Jin, J., Liu, H., Zhou, X., Gao, W., 2018. Evaluation of coal and shale reservoir in Permian coal-bearing strata for development potential: A case study from well LC-1# in the northern Guizhou, China. Energy Exploration & Exploitation 37, 194-218. reservoir characteristics of coals and their associated shales is very important in understanding the co-exploration and co-production potential of unconventional gases in Guizhou, China. Accordingly, comprehensive experimental results of 12 core samples from well LC-1# in the northern Guizhou were used and analyzed in this paper to better understand their vertical reservoir study. Coal and coal measured shale, in Longtan Formation, are rich in organic matter, with postmature stage of approximately 3.5% and shales of type III kerogen with dry gas generation. All-scale pore size analysis indicates that the pore size distribution of coal and shale pores is mainly less than 20 nm and 100 nm, respectively. Pore volume and area of coal samples influenced total gas content as well as desorbed gas and lost gas content. Obvious relationships were observed between residual gas and BET specific surface area and BJH total pore volume (determined by nitrogen adsorption). For shale, it is especially clear that the desorbed gas content is negatively correlated with BET specific surface area, BJH total pore volume and clay minerals. However, the relationships between desorbed gas and TOC (total organic carbon) as well as siderite are all well positive. The coals and shales were shown to have similar anoxic conditions with terrestrial organic input, which is beneficial to development of potential source rocks for gas. However, it may be better to use a low gas potential assessment for shales in coal-bearing formation because of their low S1+S2 values and high thermal evolution. Nevertheless, the coalbed methane content is at least 10 times greater than the shale gas content with low desorbed gases, indicating that the main development unconventional natural gas should be coalbed methane, or mainly coalbed methane with supplemented shale gas.Xu, J., Liu, Z., Bechtel, A., Sachsenhofer, R.F., Jia, J., Meng, Q., Sun, P., 2019. Organic matter accumulation in the Upper Cretaceous Qingshankou and Nenjiang Formations, Songliao Basin (NE China): Implications from high-resolution geochemical analysis. Marine and Petroleum Geology 102, 187-201. Songliao Basin is well-known as one of most prolific petroleum basins in China. Information regarding Upper Cretaceous organic matter (OM) accumulation within black shales of the Qingshankou and Nenjiang Formations (Fm) can be obtained by geochemical analyses. Two oil shale successions at the bottom of the Qingshankou Fm first member (K2qn1) and Nenjiang Fm second member (K2n2) are investigated in high resolution to reveal the factors that govern OM accumulation. Within the two target profiles, combined petrological and geochemical results indicate that OM accumulation can be divided into two phases: (i) a lower phase characterized by high primary productivity, enhanced input of terrigenous OM and anaerobic conditions of OM deposition (TOC maximum 18.25?wt%) and (ii) an upper phase of lower primary productivity and anoxic to dysoxic conditions in bottom water (TOC maximum 9.45?wt%). Alternations of warmer and wetter climatic conditions provided the nutrients, and fluctuations in lake level are suggested to be responsible for differences in redox conditions and bioproductivity between the two phases. Marine ingressions enhanced OM preservation by promoting bottom water salinity (e.g., anaerobic conditions with brackish-saline water within K2qn1 lower phase). The identification of different OM accumulation mechanisms by high-resolution geochemical analyses are expected to improve the prediction of high quality source rocks within uniform depositional environments.Xu, L., Wang, Y., Liu, L., Chen, L., Chen, J., 2018. Evolution characteristics and model of nanopore structure and adsorption capacity in organic-rich shale during artificial thermal maturation: A pyrolysis study of the Mesoproterozoic Xiamaling marine shale with type II kerogen from Zhangjiakou, Hebei, China. Energy Exploration & Exploitation 37, 493-518. maturity has a considerable impact on hydrocarbon generation, mineral conversion, nanopore structure, and adsorption capacity evolution of shale, but that impact on organic-rich marine shales containing type II kerogen has been rarely subjected to explicit and quantitative characterization. This study aims to obtain information regarding the effects of thermal maturation on organic matter, mineral content, pore structure, and adsorption capacity evolution of marine shale. Mesoproterozoic Xiamaling immaturity marine oil shale with type II kerogen in Zhangjiakou of Hebei, China, was chosen for anhydrous pyrolysis to simulate the maturation process. With increasing simulation temperature, hydrocarbon generation and mineral transformation promote the formation, development, and evolution of pores in the shale. The original and simulated samples consist of closed microspores and one-end closed pores of the slit throat, all-opened wedge-shaped capillaries, and fractured or lamellar pores, which are related to the plate particles of clay. The increase in maturity can promote the formation and development of pores in the shale. Heating can also promote the accumulation, formation, and development of pores, leading to a large pore volume and surface area. The temperature increase can promote the development of pore volume and surface area of 1–10 and 40-nm diameter pores. The formation and development of pore volume and surface area of 1–10 nm diameter pores are more substantial than that of 40-nm diameter pores. The pore structure evolution of the sample can be divided into pore adjustment (T?<?350°C, EqRo?<?0.86%), development (350°C?<?T?<?650°C, 0.86%?<?EqRo?<?3.28%), and conversion or destruction stages (T?>?650°C, EqRo?>?3.28%). Along with the increase in maturity, the methane adsorption content decreases in the initial simulation stage, increases in the middle simulation stage, and reaches the maximum value at 650°C, after which it gradually decreases. A general evolution model is proposed by combining the nanopore structure and the adsorption capacity evolution characteristics of the oil shale.Yadav, A., Chattopadhyay, K., Singh, R., Mondal, S., Chopra, A., Christopher, J., Kapur, G.S., 2018. Novel HPLC-RI-UV based method for simultaneous estimation of saturates, olefins, conjugated dienes and aromatics in full range cracked gasoline. Petroleum Science and Technology 36, 1805-1811. fast method based on High performance liquid chromatography technique for the estimation of Saturates, Olefins, Conjugated dienes and Aromatics in Cracked gasoline samples has been developed. In this work, the focus was on choosing the right reference standard against which olefin could be estimated. The olefin reference standard was first shortlisted using Nuclear Magnetic Resonance spectroscopy and Gas chromatography based Simulated Distillation analysis as per ASTM D2887. The values estimated against shortlisted standards using HPLC were compared with values obtained using standard Flourescent Indicator Adsorption(FIA) based ASTM D1319 method to select one. The aromatics were estimated against o-Xylene.Yang, L., Chen, W., Zhuang, W.-E., Cheng, Q., Li, W., Wang, H., Guo, W., Chen, C.-T.A., Liu, M., 2019. Characterization and bioavailability of rainwater dissolved organic matter at the southeast coast of China using absorption spectroscopy and fluorescence EEM-PARAFAC. Estuarine, Coastal and Shelf Science 217, 45-55. brings considerable amounts of dissolved organic matter (DOM) from atmosphere to freshwater and marine environments, but little is known about the chemical composition and bioavailability of rainwater DOM. The quantity, quality, and bioavailability of DOM were investigated for 21 rain events at a coastal site in southeast China, using dissolved organic carbon (DOC) measurements, absorption spectroscopy, and fluorescence excitation-emission matrices-parallel factor analysis (EEM-PARAFAC). The DOC concentration ranged from 35 to 457?μM, which was affected by the prevailing monsoon, rainfall amount and terrestrial/anthropogenic inputs. The volume-weighted average DOC was 118?μM, corresponding to a rainwater DOC flux of 1.98?g?m?2 yr?1. Four fluorescent components were identified with EEM-PARAFAC, including three humic-like components (C1-C3) and one tyrosine-like component C4. Absorption coefficient (aCDOM(300)) and fluorescence intensities of C2-C4 strongly correlated with DOC, indicating they can be used for DOC estimation. Rainwater DOM was characterized by low DOC-specific UV absorbance (SUVA254) and humification index (HIX), which indicated a low aromaticity and humification degree. Principal component analysis (PCA) based on DOM indices revealed two principal factors, which were related to the DOM concentration and humification degree respectively. PCA, together with air-mass trajectory analysis, successfully separated different rain events with variable inputs from living plants/local sources, soil organic matter/humified materials, and the marine source. Rainwater DOM generally showed a high bioavailability of 50%?±?19%, with higher degradability of non-chromophoric constituents and C1-C2 than other components. This study demonstrated the applicability of absorption and EEM-PARAFAC combined with PCA and air-mass trajectory analysis in differentiating rain events and tracking organic matter sources, and revealed different effects of microbial degradation on individual PARAFAC components in rainwater.Yang, L., Ran, B., Han, Y.-Y., Liu, S.-G., Ye, Y.-H., Xiao, C., Sun, W., Yang, D., Xia, G.-D., Wang, S.-Y., 2019. Sedimentary environment controls on the accumulation of organic matter in the Upper Ordovician Wufeng–Lower Silurian Longmaxi mudstones in the Southeastern Sichuan Basin of China. Petroleum Science 16, 44-57. Upper Ordovician–Lower Silurian mudstones (including the Wufeng, Guanyinqiao and Longmaxi Formations) in the Sichuan Basin are some of the most important shale gas plays in China. In order to enhance our understanding of the process of formation of organic carbon up to 10%, optical, microscopy and geochemical methods have been used to investigate the petrographic and geochemical characteristics of the formation. Firstly, three mudstone lithofacies were identified based on a wide variety of mudstone laminations. These are: (a) indistinctly laminated mudstone; (b) parallel-laminated mudstone; and (c) nonparallel-laminated mudstone. Then, combining with the evidence from depocenter migration, Th/U ratios and total organic carbon, the abundant organo-minerallic fabrics suggest that organic carbon was preferentially deposited and preserved in anoxic, low energy and stagnant water conditions during deposition of the Wufeng and Longmaxi Formations. On the contrary, the Guanyinqiao Formation with poor organic carbon was deposited in oxic and high-energy water conditions.Yang, Y., Liang, Y., Yang, J., Ye, F., Zhou, T., Gongke, L., 2019. Advances of supercritical fluid chromatography in lipid profiling. Journal of Pharmaceutical Analysis 9, 1-8. fluid chromatography (SFC) meets with great favor due to its high efficiency, low organic solvent consumption, and the specialty for the identification of the isomeric species. This review describes the advances of SFC in targeted and untargeted lipid profiling. The advancement of the SFC instruments and the stationary phases were summarized. Typical applications of SFC to the targeted and untargeted lipid profiling were discussed in detail. Moreover, the perspectives of SFC in the lipid profiling were also proposed. As a useful and promising tool for investigating lipids in vitro and in vivo, SFC will predictably obtain further development.Yang, Y., Liu, G., Song, W., Ye, C., Lin, H., Li, Z., Liu, W., 2019. Plastics in the marine environment are reservoirs for antibiotic and metal resistance genes. Environment International 123, 79-86. have been accumulated offshore and in the deep oceans at an unprecedented scale. Microbial communities have colonized the plastisphere, which has become a reservoir for both antibiotic and metal resistance genes (ARGs and MRGs). This is the first analysis of the diversity, abundance, and co-occurrence of ARGs and MRGs, and their relationships within the microbial community, using metagenomic data of plastic particles observed in the North Pacific Gyre obtained from the National Centre for Biotechnology Information Sequence Read Archive database. The abundance of ARGs and MRGs in microbial communities on the plastics were in the ranges 7.07?×?10?4–1.21?×?10?2 and 5.51?×?10?3–4.82?×?10?2 copies per 16S rRNA, respectively. Both the Shannon-Wiener indices and richness of ARGs and MRGs in plastics microbiota were significantly greater than those of ARGs and MRGs in seawater microbiota in the North Pacific Gyre via one-way analysis of variance. Multidrug resistance genes and multi-metal resistance genes were the main classes of genes detected in plastic microbiota. There were no significant differences in the abundance or diversity of ARGs and MRGs between macroplastics biota and microplastics biota, indicating that particle size had no effect on resistance genes. Procrustes analysis suggested that microbial community composition was the determining factor of the ARG profile but not for MRG. Some ARGs and MRGs had a higher incidence of non-random co-occurrence, suggesting that the co-effects of selection for antibiotic or metal resistance are important factors influencing the resistome of the microbiota on the plastic particles.Yao, S., Lyu, S., An, Y., Lu, J., Gjermansen, C., Schramm, A., 2019. Microalgae–bacteria symbiosis in microalgal growth and biofuel production: a review. Journal of Applied Microbiology 126, 359-368. Photosynthetic microalgae can capture solar energy and convert it to bioenergy and biochemical products. In nature or industrial processes, microalgae live together with bacterial communities and may maintain symbiotic relationships. In general interactions, microalgae exude dissolved organic carbon that becomes available to bacteria. In return, the bacteria remineralize sulphur, nitrogen and phosphorous to support the further growth of microalgae. In specific interactions, heterotrophic bacteria supply B vitamins as organic cofactors or produce siderophores to bind iron, which could be utilized by microalgae, while the algae supply fixed carbon to the bacteria in return. In this review, we focus on mutualistic relationship between microalgae and bacteria, summarizing recent studies on the mechanisms involved in microalgae?bacteria symbiosis. Symbiotic bacteria on promoting microalgal growth are described and the relevance of microalgae?bacteria interactions for biofuel production processes is discussed. Symbiotic microalgae?bacteria consortia could be utilized to improve microalgal biomass production and to enrich the biomass with valuable chemical and energy compounds. The suitable control of such biological interactions between microalgae and bacteria will help to improve the microalgae-based biomass and biofuel production in the future.Yaseen, S., Mansoori, G.A., 2018. Asphaltene aggregation onset during high-salinity waterflooding of reservoirs (a molecular dynamic study). Petroleum Science and Technology 36, 1725-1732. primary objective of this study is to establish an understanding of the role of high-salinity brine on the intensity of asphaltene aggregation onset during waterflooding of petroleum reservoirs. We already have shown that asphaltenes have a high tendency to form aggregates during waterflooding process when pure- and low salinity-water are injected into reservoirs. To fulfill the present objective, molecular dynamic simulations are performed on asphaltenic-oil/aqueous systems at 550 K-200?bar. The oil phase consists of asphaltenes (10?wt.%) and ortho-xylene, in which asphaltene molecules are completely soluble. Our simulations results reveal that the ?salt-in effect? of high-salinity brine (25 wt.% NaCl) on seven different model asphaltenic oils causes a significant reduction of the onset of asphaltene aggregation as compared with pure-water. Such ?salt-in effect? is primarily due to a considerable reduction of water miscibility in the oil phase at high pressure and temperature.You, C., Yao, T., Xu, C., 2019. Environmental significance of levoglucosan records in a central Tibetan ice core. Science Bulletin 64, 122-127. environmental significance of levoglucosan (LEV) records in Tibetan glacier ice layers on sub-annual to annual scales, in particular their suitability as a specific biomarker for indicating past fire changes, is poorly understood at present. In this work, a continuous LEV record was reconstructed in a central Tibetan ice core for the period 1990–2012. The LEV record was classified into two categories based on its LEV concentrations: background levels and extreme events. Annually-resolved LEV records and background levels in the ice core were strongly correlated with satellite observations of fire occurrence frequency over the northern Indian peninsula between 2003 and 2012, especially for strong fire events during the pre-monsoon season (March–May). In addition, peaks in LEV concentrations may represent extreme fire events in regions around the Tibetan Plateau. LEV records in the ice core reflect a long-term increasing trend in fire background and also an increase in fire extreme events, across the Tibetan Plateau and its surroundings. We therefore conclude that LEV records in Tibetan ice cores can be used as a powerful tool for calibrating and reconstructing past fire changes over subtropical Asia.Yousefi Lalimi, F., Silvestri, S., D'Alpaos, A., Roner, M., Marani, M., 2018. The spatial variability of organic matter and decomposition processes at the marsh scale. Journal of Geophysical Research: Biogeosciences 123, 3713-3727. rate in salt marshes is governed by inorganic soil deposition and soil organic matter (SOM) accumulation. Existing (limited) observations and modeling results suggest that SOM amounts, biomass production, and decomposition processes should vary widely and systematically at the marsh scale. However, we lack observations aimed at understanding how SOM production is modulated spatially within a marsh, and at elucidating the relative importance of the controlling processes. The little existing data suggest that competing effects between biomass production and decomposition processes determine an approximately spatially constant contribution of SOM to total accretion. Here we investigate this idea using concurrent observations of SOM and decomposition rates from marshes in North Carolina. Our results indicate that systematic spatial variations in SOM are small, possibly as a result of an at least partial compensation of opposing trends in biomass production and decomposed organic matter. Our analyses show that deeper soil layers are, on average, characterized by lower decomposition rates and higher stabilization factors than shallower layers, likely because of differences in the persistence of water-logged conditions. Overall, decomposition processes are sufficiently rapid that the labile material in the fresh biomass is completely decomposed before it can be sufficiently buried and stabilized. Our findings point to the importance of the fraction of initially refractory material and of stabilization processes in determining the final distribution of SOM within the soil column.Yu, F., Fu, X., Xu, G., Wang, Z., Chen, W., Zeng, S., Song, C., Feng, X., Wan, Y., Li, X., 2019. Geochemical, palynological and organic matter characteristics of the Upper Triassic Bagong Formation from the North Qiangtang Basin, Tibetan Plateau. Palaeogeography, Palaeoclimatology, Palaeoecology 515, 23-33. Upper Triassic Bagong mudstones are considered to be the most significant source rocks in the eastern part of North Qiangtang Basin, Tibetan Plateau. This study investigates the vertical variation of total organic carbon (TOC) contents as well as mineral compositions, carbon isotope, palynology, major and trace element concentrations of the Upper Triassic sediments from Geladandong area of North Qiangtang Basin to understand the mechanism of organic matter accumulation. The TOC concentrations of Bagong Formation mudstone range from 0.77 to 1.37% (mean 1.04%), while the Boni La Formation micritic limestone displays lower TOC contents (0.18–0.37%, average 0.26%). Terrigenous flux proxies including Al, Si, Ti, Th, and Zr concentrations suggest that relatively high detrital flows originate from aluminosilicate compositions during the Upper Triassic sediment deposition. The paleoredox indicators (MoEF/UEF and Corg/P) reflect an oxic-suboxic condition during deposition of the Bagong mudstones and Boni La micritic limestones. The correlation between TOC and Porg and Babio indicates that the Upper Triassic Bagong mudstone has a higher primary productivity compared with most of the Boni La micritic limestone. The palynological investigation and climate proxy (B/Ga and illite/smectite) reflect warm and humid to hot and sub-humid climate condition during the Bagong mudstone deposition. The warm and humid climate condition is favorable for the survival of organisms, which in turn would enhance the primary productivity of surface water. Relatively high primary productivity is the main factor for the organic carbon accumulation in the Upper Triassic Bagong mudstones. In addition, the relatively fast sedimentation rate resulting in preservation a high TOC content of Bagong mudstone deposit in an oxic-suboxic condition. The low primary productivity and the high carbonate production lead to the dilution of organic matter with respect to the low TOC content of Boni La micritic limestone.Yu, K., Shao, C., Ju, Y., Qu, Z., 2019. The genesis and controlling factors of micropore volume in transitional coal-bearing shale reservoirs under different sedimentary environments. Marine and Petroleum Geology 102, 426-438. micropores (pore size?<?2?nm) that develop in coal-bearing shale reservoirs are of great significance to the adsorption and storage of shale gas. To investigate the characteristics and genesis of micropore volume in transitional coal-bearing shale, we selected 18 coal-bearing shale samples deposited in four types of sedimentary environments (carbonate tidal flat, pro-delta, delta front, and delta plain), using low-pressure CO2 adsorption, X-ray diffraction (XRD), vitrinite reflectance (Ro), and total organic carbon (TOC) analysis. The results first indicate that two meaning peaks are present in the distribution curve of micropore volume in transitional coal-bearing shale, which are peak 2 (0.4577–0.6272?nm) and peak 3 (0.8216?nm), while the pore volume of peak 1 may be a false peak caused by the testing principle. The hydrodynamic intensity in different sedimentary environments is the key variable in determining the characteristics of micropores. In a weak hydrodynamic environment, the higher the hydrodynamic intensity, the lower the pore volume of peaks and total micropore volume, while the opposite is true in a strong hydrodynamic environment. When the hydrodynamic force reaches a certain intensity, the pore volume of peaks and the total micropore volume decrease rapidly. The quartz in transitional shale typically contains a small number of micropores, resulting in a reduction in the micropore volume. Meanwhile, the clay minerals process substantial micropores and work together with organic matter (OM) to change the pore structure of shale, resulting in an increase in the micropore volume. Moreover, the influence of clay minerals on the total micropore volume and pore volume of peak 2 is slightly higher than that of TOC, while the opposite was found for peak 3. Overall, the OM micropores of peak 2 are interlaminar pores of aromatic rings or other types of OM pores, the OM micropores of peak 3 correspond to the columnar pores formed by ordered stacking of aromatic rings, and the micropores in clay minerals are the spacings in the inner layers of kaolinite and chlorite.Yu, M., Olkowicz, M., Pawliszyn, J., 2019. Structure/reaction directed analysis for LC-MS based untargeted analysis. Analytica Chimica Acta 1050, 16-24. LC-MS based untargeted analysis, data is collected at the peak or ion level, although the investigated biochemistry processes occur at the compound or reaction level. To this end, the presence of redundancy peaks such as co-eluted peaks, multi-chargers, adducts, neutral loss, isotopologues, and fragments ions often muddle subsequent statistical data analysis. In order to fill this gap, between peaks and compounds/reactions, independent components must first be found at the peak level, then evaluated at the compound or reaction levels. Based on paired mass distances (PMD), the algorithm GlobalStd, based on retention time hierarchical cluster analysis and global analysis of PMDs within clusters, is here proposed to extract independent peaks from raw LC-MS data. Following its application, a structure/reaction directed analysis can then be used to evaluate compounds at the structure or biochemistry reaction level, based on similar PMDs among different retention times clusters. As a proof-of-concept, the developed statistical method was applied to data obtained for in?vivo SPME sampling on fish. In total, 277 independent peaks were demonstrated to stand for most of the variances found for the total 1459 ions detected via LC-MS. Following, both known homologous series or biological reactions along with unknown bio-processes, which may involve oxidation/reduction reactions or homologous series, were analyzed via a structure/reaction directed analysis. The findings of this analysis yielded interesting information regarding the data, for instance denoting the possible occurrence of a biosynthesis process involving l-Carnitine and its precursor 4-Trimethylammoniobutanoic acid. Such PMD relationships could also aid in the screening of annotation results. To this end, semi-quantitative analysis based on structure/reaction directed analysis is also here proposed for further investigation of unknown patterns or for removal of contaminants in metabolomics studies. The developed data-driven algorithm has been included in a PMD package with a GUI interactive document, and is freely available online ().Yu, W., Polgári, M., Gyollai, I., Fintor, K., Szabó, M., Kovács, I., Fekete, J., Du, Y., Zhou, Q., 2019. Microbial metallogenesis of Cryogenian manganese ore deposits in South China. Precambrian Research 322, 122-135. Datangpo Formation manganese deposits (DFMnD) in South China formed during the interglacial stage between the Sturtian and Marinoan glaciations of the Cryogenian period. These black shale-hosted deposits are composed of massive Mn-carbonates with microscopic laminae/laminations and cherty veins. To date, it has been thought that the DFMnD formed through inorganic processes, which were controlled by redox changes in the post-Sturtian Nanhua Rift Basin, South China. However, in this study, systematic petrographic, mineralogical, and geochemical analyses indicate a microbially mediated origin of the Mn ore deposits. Mineralized microbial woven micro-textures (observed at the μm scale) and microbial fossils are common in the laminated Mn-carbonate ores. We infer that microbial enzyme activity formed poorly crystallized Mn oxide/hydroxides and carbonaceous material, which transformed to rhodochrosite, kutnohorite, ankerite/dolomite, framboidal pyrite, and apatite via diagenesis. Some micro-scale quartz and K-feldspar may be detrital but most appears to have formed during diagenesis or through hydrothermal activity. A micro-mineralogical profile determined by 2500 spectra via high-resolution in situ micro-Raman spectroscopy also revealed cyclic laminations of Ca-rhodochrosite as microbialite (ankerite/dolomite) and quartz, indicating a mineralized biomat system. Ca-rhodochrosite transformed to kutnohorite under elevated temperatures, as indicated by the maturation level of organic matter (determined via Raman spectroscopy). Alternating micro-laminae denote cyclic changes in microbial groups (Mn- and Fe-oxidizing microbes versus cyanobacteria) during the formation of the Mn ore deposits. Our proposed model for the microbially mediated metallogenesis of Mn-carbonate deposits begins with enzymatic multi-copper oxidase processes associated with autotrophic microbial activity under obligatory oxic conditions, which results in the precipitation of Mn bio-oxides. Following their burial in organic-rich sediments, the Mn(IV) oxides and hydroxides are reduced, producing soluble Mn(II) via processes mediated by heterotrophic microbes under suboxic conditions, which in turn form the Mn-carbonates. This microbial metallogenesis model for the Cryogenian DFMnD in South China is similar to that proposed for the Jurassic ?rkút Mn deposit in Hungary, indicating that a two-step microbially mediated process of Mn ore formation might be common throughout geological history.Yu, Y.-J., Zheng, Q.-X., Zhang, Y.-M., Zhang, Q., Zhang, Y.-Y., Liu, P.-P., Lu, P., Fan, M.-J., Chen, Q.-S., Bai, C.-C., Fu, H.-Y., She, Y., 2019. Automatic data analysis workflow for ultra-high performance liquid chromatography-high resolution mass spectrometry-based metabolomics. Journal of Chromatography A 1585, 172-181. analysis for ultra-performance liquid chromatography high-resolution mass spectrometry-based metabolomics is a challenging task. The present work provides an automatic data analysis workflow (AntDAS2) by developing three novel algorithms, as follows: (i) a density-based ion clustering algorithm is designed for extracted-ion chromatogram extraction from high-resolution mass spectrometry; (ii) a new maximal value-based peak detection method is proposed with the aid of automatic baseline correction and instrumental noise estimation; and (iii) the strategy that clusters high-resolution m/z peaks to simultaneously align multiple components by a modified dynamic programing is designed to efficiently correct time-shift problem across samples. Standard compounds and complex datasets are used to study the performance of AntDAS2. AntDAS2 is better than several state-of-the-art methods, namely, XCMS Online, Mzmine2, and MS-DIAL, to identify underlying components and improve pattern recognition capability. Meanwhile, AntDAS2 is more efficient than XCMS Online and Mzmine2. A MATLAB GUI of AntDAS2 is designed for convenient analysis and is available at the following webpage: , G., Cao, Y., Zan, N., Schulz, H.-M., Gluyas, J., Hao, F., Jin, Q., Liu, K., Wang, Y., Chen, Z., Jia, Z., 2019. Coupled mineral alteration and oil degradation in thermal oil-water-feldspar systems and implications for organic-inorganic interactions in hydrocarbon reservoirs. Geochimica et Cosmochimica Acta 248, 61-87. interactions after oil charging are critical for determining the ongoing evolution of hydrocarbons and rock quality in water-wet siliciclastic reservoirs. It is the conceptual approach of this study to simulate and decipher these interactions by using quantitative analyses of the interrelated changes of minerals, water, hydrocarbons, gases, and organic acids in heated oil-water-rock systems. The experimental results show that organic-inorganic interactions occur between the organic oil and inorganic feldspar in the presence of water. Water promotes the oil degradation by an extra supply of H+ and OH? ions. In the oil-water-rock systems, mutual exchanges of H+ and OH? ions among minerals, water, and hydrocarbons probably result in the mutual interactions between oil degradation and mineral alteration, with water serving as a matrix for the ion exchange. In the oil-water-feldspar system, feldspar alteration does not cease in the oil zone in the presence of some water and, inversely, oil degradation can even accelerate the alterations of the aluminosilicate minerals. The mineral alterations from feldspar to boehmite, illite, and muscovite promote the oil degradation in the oil-deionized water-feldspar systems with the mutual ion exchange. Due to a possible competition between the Br?nsted acid sites in the minerals and the halide anions or the direct replacement of K-feldspar by albite, the mineral alterations retard the oil degradation in the oil-NaCl water-feldspar systems. The experimental results also indicate that oil degradation via free radical cross-linking and free radical thermal cracking is extensive in anhydrous oil systems and may lead to blocking of pores and throats by the generated pyrobitumen in the oil zone of a reservoir. In contrast, in the oil-water transition zone of a reservoir, oil degradation via thermal cracking and oxidative decomposition may dominate the oil degradation and may lead to the generation of secondary pores with leaching of minerals by the generated CO2 and organic acids. This study demonstrates that organic-inorganic interactions are complex and proceed in diverse pathways in different hydrogeochemical systems. Thus, further quantitative investigations of the reaction pathways and reaction kinetics of coupled mineral alteration and oil degradation in oil-water-rock systems are warrented. Meanwhile, the incorporation of such organic-inorganic reactions into geochemical models will improve the prediction of the evolution of organic and inorganic species in petroleum reservoirs.Yuan, W., Liu, G., Xu, L., Niu, X., Li, C., 2018. Petrographic and geochemical characteristics of organic-rich shale and tuff of the Upper Triassic Yanchang Formation, Ordos Basin, China: implications for lacustrine fertilization by volcanic ash. Canadian Journal of Earth Sciences 56, 47-59. Upper Triassic Chang 7 Member lacustrine organic-rich shale of the Yanchang Formation of the Ordos Basin is a significant hydrocarbon source rock containing abundant of tuff intervals ranging from millimeters to tens of centimeters thick. The present study relies upon petrographic and geochemical data of Chang 7 tuff intervals and organic-rich shale to consider fertilization of the lake surface by volcanic debris as a triggering mechanism of black shale sedimentation. Paleoproductivity proxies, including P/Al, Ni/Al, and Cu/Al, display elevated values in association with tuff intervals, suggesting increased productivity induced by volcanic nutrient seeding of the lake surface. Moreover, vertical variations of TOC mimic trends of paleoproductivity proxies, indicating that primary productivity was critical to organic carbon enrichment of the Chang 7 Member. Previous studies have postulated that lake bottom redox conditions were predominantly oxic–suboxic during deposition of the Chang 7 and that these deposits accumulated slowly, neither of which would have favored the export and preservation of organic matter in the absence of enhanced productivity. Accumulation of the organic-rich Chang 7 shale demonstrates the critical role that intensified primary productivity triggered by volcanism can play in the accumulation of carbonaceous sediment.Yuan, Y., Zhang, H., Wei, Y., Si, Y., Li, G., Zhang, F., 2019. Onsite quantifying electron donating capacity of dissolved organic matter. Science of The Total Environment 662, 57-64. donating capacity (EDC) of dissolved organic matter (DOM) impacts the redox behaviors of DOM in surface waters, groundwaters, wetlands, sediments and soils but lacks applicable onsite quantification methods. To address these disadvantages, a simple and portable device with pre-injected [2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonicacid), ABTS·+] was developed that can be used for EDC onsite measurements of DOM in this work. The proposed device and method had better limits of quantification of Trolox (0.2?nmol) and more flexible DOC concentration requirement of 0.5–20?mg?L?1 than that of flow injection analysis (FIA) (5–10?mg?L?1) or mediated electrochemical oxidation (MEO) (>20?mg?L?1). The proposed device and method greatly reduced the preparation and measurement time for sample tests compared to MEO or FIA method, enabling time-efficient EDC determination for large amount of samples. Meanwhile, the proposed device presented comparable accuracy with established MEO method when quantifying the EDCs of 7 standard humic and fulvic acids. Humic acids with higher molecular weight (MW) (<15,000?Da) had higher EDC than that with low MW (<5000?Da). EDCs of DOM in natural and reclaim water samples were both presented significantly positive correlations with their corresponding chemical oxygen demand, chromophoric DOM content, molecular weight and humification of the DOM in water samples. These results suggested that our device could accurately quantify the EDCs of DOM onsite and had promising applications on the fast quality assessment of natural and reclaimed waters.Zaikova, E., Goerlitz, D.S., Tighe, S.W., Wagner, N.Y., Bai, Y., Hall, B.L., Bevilacqua, J.G., Weng, M.M., Samuels-Fair, M.D., Johnson, S.S., 2019. Antarctic relic microbial mat community revealed by metagenomics and metatranscriptomics. Frontiers in Ecology and Evolution 7, 1. doi: 10.3389/fevo.2019.00001. upslope from the modern lakes in the McMurdo Dry Valleys of Antarctica are relict lake deposits embedded in valley walls. Within these relict deposits, ancient microbial mats, or paleomats, have been preserved under extremely arid and cold conditions since the receding of larger paleolakes thousands of years ago and now serve as a sheltered niche for microbes in a highly challenging oligotrophic environment. To explore whether paleomats could be repositories for ancient lake cells or were later colonized by soil microbes, determine what types of metabolic pathways might be present, analyze potential gene expression, and explore whether the cells are in a vegetative or dormant state, we collected paleomat samples from ancient lake facies on the northern slopes of Lake Vanda in Wright Valley in December 2016. Using a gentle lysis technique optimized to preserve longer molecules, combined with a polyenzymatic treatment to maximize yields from different cell types, we isolated high-molecular weight DNA and RNA from ancient paleomat samples. Community composition analysis suggests that the paleomat community may retain a population of indigenous mat cells that may flourish once more favorable conditions are met. In addition to harboring a diverse microbial community, paleomats appear to host heterotrophs in surrounding soils utilizing the deposits as a carbon source. Whole genome long-read PacBio sequencing of native DNA and Illumina metagenomic sequencing of size-sorted DNA (>2,500 nt) indicated possible cell viability, with mat community composed of bacterial taxa. Metagenome assemblies identified genes with predicted roles in nitrogen cycling and complex carbohydrate degradation, and we identified key metabolic pathways such as stress response, DNA repair, and sporulation. Metatranscriptomic data revealed that the most abundant transcripts code for products involved in genetic information processing pathways, particularly translation, DNA replication, and DNA repair. Our results lend new insight into the functional ecology of paleomat deposits, with implications for our understanding of cell biology, Antarctic microbiology and biogeography, and the limits of life in extremely harsh environments.Zakharov, D.O., Bindeman, I.N., 2019. Triple oxygen and hydrogen isotopic study of hydrothermally altered rocks from the 2.43–2.41?Ga Vetreny belt, Russia: An insight into the early Paleoproterozoic seawater. Geochimica et Cosmochimica Acta 248, 185-209. early Paleoproterozoic represents a period of rapid changes in Earth systems that could have affected the stable isotopic composition of seawater. The well-preserved pillow structures, hyaloclastites and komatiitic basalts of the 2.43–2.41?Ga Vetreny belt, Baltic Shield provide a record of high-temperature water-rock interaction induced by contemporaneous seawater. Here we present results of mineralogical, fluid inclusion, hydrogen, and triple oxygen isotopic analysis of hydrothermal alteration products. Emphasis is given to vein-filling quartz and epidote as they likely formed at high water-rock ratios. Ten minerals pairs, quartz-epidote and quartz-calcite, returned temperatures of isotopic equilibrium between 286 and 387?°C, which compares well to the homogenization temperatures measured for saline fluid inclusions hosted in vein quartz. The computed δD and δ18O values of equilibrium fluids range between ?31 and +12‰, and ?1.36 and +3.20‰, respectively, which overlap with the isotopic composition of ice-free world seawater and fluids generated at submarine hydrothermal systems. This is the earliest piece of evidence suggesting that early Paleoproterozoic seawater had a δD value close to 0‰. We also present triple oxygen isotopic composition of quartz and epidote that formed in similar facies of hydrothermal alteration from the relatively young (6–7?Ma) oceanic crust as sampled by the ODP Hole 504B in the eastern Pacific Ocean. These data show similarity to the triple oxygen isotope analyses of the Vetreny belt rocks indicating that the 2.43–2.41?Ga seawater had the Δ17O value close to that of modern-day seawater. Due to small fractionation at 300–390?°C (αepidote-water?≈?1), epidotes present a strong evidence that equilibrium fluids had Δ′17O values close to 0‰. Based on the previously published quartz-water calibration, the computed Δ17O values of equilibrium fluids range between ?0.11 and ?0.03‰, significantly lower than that of seawater or inferred seawater-derived fluids at low water-rock ratios. This can be explained by multiple factors including phase separation of fluids or/and presence of low-temperature quartz overgrowths. Both are reflected in the fluid inclusion data and in situ δ18O measurements by ion microprobe (SIMS) presented here. Overall, our study suggests that the δ18O, Δ17O and δD values of the 2.43–2.41?Ga seawater were ?1.7?±?1.1, ?0.001?±?0.011 and 0?±?20‰ respectively, similar to the modern values, which reflects the dominant role of submarine hydrothermal alteration in the stable isotopic budget of seawater throughout Earth’s history.Zanna, L., Khatiwala, S., Gregory, J.M., Ison, J., Heimbach, P., 2019. Global reconstruction of historical ocean heat storage and transport. Proceedings of the National Academy of Sciences 116, 1126-1131.: Since the 19th century, rising greenhouse gas concentrations have caused the ocean to absorb most of the Earth’s excess heat and warm up. Before the 1990s, most ocean temperature measurements were above 700 m and therefore, insufficient for an accurate global estimate of ocean warming. We present a method to reconstruct ocean temperature changes with global, full-depth ocean coverage, revealing warming of 436 ×10 21 ×1021 J since 1871. Our reconstruction, which agrees with other estimates for the well-observed period, demonstrates that the ocean absorbed as much heat during 1921–1946 as during 1990–2015. Since the 1950s, up to one-half of excess heat in the Atlantic Ocean at midlatitudes has come from other regions via circulation-related changes in heat transport.Abstract: Most of the excess energy stored in the climate system due to anthropogenic greenhouse gas emissions has been taken up by the oceans, leading to thermal expansion and sea-level rise. The oceans thus have an important role in the Earth’s energy imbalance. Observational constraints on future anthropogenic warming critically depend on accurate estimates of past ocean heat content (OHC) change. We present a reconstruction of OHC since 1871, with global coverage of the full ocean depth. Our estimates combine timeseries of observed sea surface temperatures with much longer historical coverage than those in the ocean interior together with a representation (a Green’s function) of time-independent ocean transport processes. For 1955–2017, our estimates are comparable with direct estimates made by infilling the available 3D time-dependent ocean temperature observations. We find that the global ocean absorbed heat during this period at a rate of 0.30 ± 0.06 W/m 2 m2 in the upper 2,000 m and 0.028 ± 0.026 W/m 2 m2 below 2,000 m, with large decadal fluctuations. The total OHC change since 1871 is estimated at 436 ± 91 ×10 21 ×1021 J, with an increase during 1921–1946 (145 ± 62 ×10 21 ×1021 J) that is as large as during 1990–2015. By comparing with direct estimates, we also infer that, during 1955–2017, up to one-half of the Atlantic Ocean warming and thermosteric sea-level rise at low latitudes to midlatitudes emerged due to heat convergence from changes in ocean transport.Zeng, Q., Wu, Y., Liu, Y., Zhang, G., 2019. Determining the micro-fracture properties of Antrim gas shale by an improved micro-indentation method. Journal of Natural Gas Science and Engineering 62, 224-235. of the fracture properties of gas shale rocks is of key importance for more reliable and economical recovery of natural gas via hydraulic fracturing. This paper presents a new micro-indentation technique to probe the elasticity and fracture properties of Antrim gas shale. With the explicit consideration of the holding-load-constant stage at the peak load, new models with simple expressions and clear physical mechanisms were formulated. The load-displacement data of loading and unloading can be characterized by energy terms and constants. Three different displacement levels were used in the indentation tests. The elastic modulus and hardness of Antrim shale were analyzed by the new method. The fracture toughness was evaluated by the crack length-based and improved energy-based methods. Results show that both the elastic modulus and hardness decrease with increasing the displacement, which follows a homogenization process. The values of fracture toughness are relatively small and vary with the adopted data-processing methods due to the intrinsically different underlying principles. The indentation technique, together with appropriate interpreting methods, may pave paths to the accurate determination of the mechanical properties of gas shale at the nano and micro scales.Zhang, B., Liang, W., Ranjith, P.G., Li, Z., Li, C., Hou, D., 2019. Coupling effects of supercritical CO2 sequestration in deep coal seam. Energy & Fuels 33, 460-473. sequestration in deep unminable coal seams is currently identified as a research hot spot to reduce CO2 emissions, due to the potential large-scale storage capacity and complicated physical and chemical reactions, especially for supercritical CO2 (scCO2). Hitherto, the interaction mechanisms between scCO2 and coal mass in situ conditions are still unclear. Therefore, the main objective of this study is to fully address the coupling effects of scCO2 sequestration on coal mass and provide a comprehensive evaluation of the interrelation of these variations. Five cycles of helium and scCO2 injection were replicated on a subbituminous coal sample to investigate the permeability variation with scCO2 saturation time. Meanwhile, gas chromatography–mass spectrometry (GC–MS), gas chromatography (GC), Fourier transform infrared spectroscopy (FTIR), proximate analysis, and low-pressure–temperature nitrogen (N2) isotherm analyses were employed to characterize the transformation in coal mass. The test result shows the following: (1) scCO2 tended to mobilize a higher proportion of aliphatics than aromatics, and the concentration of the yielded hydrocarbons decreased with CO2 saturation time. (2) Carbonate and silicate cemented minerals were partly dissolved due to the formation of an acidic solution containing H2CO3. (3) The hydrocarbon extraction and mineral dissolution resulted in the corresponding FTIR absorbance bands being weakened and the volatile matter content and the ash content being decreased by approximately 15 and 26%, respectively. (4) The coal pore volume and the Brunauer–Emmett–Teller (BET) surface area decreased by approximately 24 and 12%, respectively. (5) Due to CO2 adsorption and the reduction of Young’s modulus with saturation time, the volumetric strain increased from 0.23 to 3.26%, which led to coal permeability decrease from 0.042 to 0.029 mdarcy. After analysis of the interrelation of these variations, the interaction mechanisms between scCO2 and coal mass in situ conditions were described and an overall negative effect on coal permeability was found.Zhang, C., Yu, Q., 2019. Breakthrough pressure and permeability in partially water-saturated shales using methane–carbon dioxide gas mixtures: An experimental study of Carboniferous shales from the eastern Qaidam Basin, China. American Association of Petroleum Geologists Bulletin 103, 273-301. an important unconventional and alternative resource, shale gas has attracted worldwide attention. The breakthrough pressure is a major factor in the generation and migration of shale gas as well as in the evaluation of the caprock sealing capacity. Carboniferous shales are considered to have great potential for the exploitation of shale gas; thus, investigations of the breakthrough pressure and gas effective permeability are significant. Two shale samples taken from the Carboniferous Hurleg Formation in the eastern Qaidam Basin, China, were chosen to conduct breakthrough experiments to investigate the effects of water saturation and CO2–CH4 mixed mole fractions on the breakthrough pressure and gas effective permeability. Prior to the experiments, various relevant parameters (e.g., the porosity, mineral composition, and organic geochemistry; the total organic content, thermal maturity and kerogen type; and microstructure) of these samples were also measured.The results of our breakthrough experiments show that the breakthrough pressure increases with the water saturation and decreases with the CO2 mole fraction in the gas mixture. The situation for the gas effective permeability is just the opposite. Pore-size distribution measurements indicate that there are many nanoscale micropores that can easily be blocked by water molecules. This results in the reduced connectivity of gas pathways; thus, the breakthrough pressure increases and the gas effective permeability decreases with increasing water saturation. The breakthrough pressure decreases with the CO2 mole fraction because the interfacial tension of the CO2–water system is smaller than that of the CH4–water system. The viscosity of the CO2–CH4 mixture was found to increase with the CO2 mole fraction by fitting a series of values under the same temperature and pressure conditions, leading to an increase in the gas effective permeability. Furthermore, CO2 molecules are smaller than CH4 molecules, making it easier for CO2 to move across pathways. After each breakthrough experiment, the CO2 mole fraction in the effluent was less than that in the injected gas, and it increased over time until reaching the initial injected gas composition. This is because the adsorption and solubility of CO2 in water are greater than those of CH4. This study provides practical information for further investigations of shale gas migration and extraction and the sealing capacities of caprocks.Zhang, J., Wei, C., Yan, G., Lu, G., 2018. Structural and fractal characterization of adsorption pores of middle–high rank coal reservoirs in western Yunnan and eastern Guizhou: An experimental study of coals from the Panguan syncline and Laochang anticline. Energy Exploration & Exploitation 37, 251-272. better understand the structural characteristic of adsorption pores (pore diameter?<?100 nm) of coal reservoirs around the coalbed methane production areas of western Yunnan and eastern Guizhou, we analyzed the structural and fractal characteristics of pore size range of 0.40–2.0 nm and 2–100 nm in middle–high rank coals (Ro,max?=?0.93–3.20%) by combining low-temperature N2/CO2 adsorption tests and surface/volume fractal theory. The results show that the coal reservoirs can be divided into three categories: type A (Ro,max?<?2.15%), type B (2.15%?<?Ro,max <2.50%), and type C (Ro,max?>?2.15%). The structural parameters of pores in the range from 2 to 100 nm are influenced by the degree of coal metamorphism and the compositional parameters (e.g., ash and volatile matter). The dominant diameters of the specific surface areas are 10–50 nm, 2–50 nm, and 2–10 nm, respectively. The pores in the range from <2 nm provide the largest proportion of total specific surface area (97.22%–99.96%) of the coal reservoir, and the CO2-specific surface area and CO2-total pore volume relationships show a positive linear correlation. The metamorphic degree has a much greater control on the pores (pore diameter less than 2 nm) structural parameters than those of the pore diameter ranges from 2 to 100 nm. Dv1 and Dv2 can characterize the structure of 2–100 nm adsorption pores, and Dv1 (volume heterogeneity) has a positive correlation with the pore structural parameters such as N2-specific surface area and N2-total pore volume. This parameter can be used to characterize volume heterogeneity of 2–10 nm pores. Dv2 (surface heterogeneity) showed type A?>?type B?>?type C and was mainly affected by the metamorphism degree. Ds2 can be used to characterize the pore surface heterogeneity of micropores in the range of 0.62–1.50 nm. This parameter has a good correlation with the pore parameters (CO2-total pore volume, CO2-specific surface area, and average pore size) and is expressed as type C?<?type B?<?type A. In conclusion, the heterogeneity of the micropores is less than that of the meso- and macropores (2–100 nm). Dv1, Dv2, and Ds2 can be used as effective parameters to characterize the pore structure of adsorption pores. This result can provide a theoretical basis for studying the pore structure compatibility of coal reservoirs in the region.Zhang, K., Song, Y., Jia, C., Jiang, Z., Jiang, S., Huang, Y., Wen, M., Liu, X., Liu, W., Chen, Z., Xie, X., Liu, T., Wang, X., Wang, P., Li, X., Shan, C.a., 2019. Vertical sealing mechanism of shale and its roof and floor and effect on shale gas accumulation, a case study of marine shale in Sichuan basin, the Upper Yangtze area. Journal of Petroleum Science and Engineering 175, 743-754. and its roof and floor are very important for shale gas preservation. How to clarify the mechanism of its vertical sealing and its effect on shale gas enrichment is a significant problem to be solved. In this paper, the objective layers are the Upper Ordovician Wufeng Formation, the first member of the Lower Silurian Longmaxi Formation and the Lower Cambrian Qiongzhusi Formation, which are all in the representative shale gas blocks in the Sichuan basin of the Yangtze region. Studied by statistical drilling data, the focus is on the detailed analyses of the JiaoYe-1, Ning-201 and Wei-201 well, and experiments were carried out such as the porosity test, the TOC content analysis and the experiment of overburden permeability, permeability experiments before and after adsorption of methane under different osmotic pressure, and isothermal adsorption experiments. The experiments results are applied on studying the effect of shale and its roof and floor on shale gas enrichment, combined with formula deduction. The results show that the roof and floor have a vertical sealing effect on the organic-rich shale by the difference of physical properties. In eastern Sichuan, the roof of the organic-rich shale of the Wufeng Formation and the first member of Longmaxi Formation is assemblage of argillaceous siltstone and siliceous shale, while in southern Sichuan it is assemblage of gray shale and siliceous shale. The floor is nodular limestone and limestone in both areas. The combination of roof and floor, with low porosity, can form a quality roof and floor sealing ability in the absence of fracture development. Its sealing ability is stronger than that in the upper part of the Qiongzhusi Formation, considering its roof and floor composed of argillaceous siltstone and siliceous shale. The floor of the organic-rich shale at the bottom of the Qiongzhusi Formation is a dolomite reservoir with good storage capacity, between which there is an unconformable contact causing the worst sealing ability among the three intervals. With the increase of burial depth, the overlying pressure of shale increases. With the increase of TOC content and thickness, the amount of adsorption gas of shale increases. These two aspects of factors can lead to the permeability decline and self-sealing enhancement of the organic-rich shale. In this study, focusing on the Upper Ordovician-Lower Silurian and the Lower Cambrian in the Sichuan basin, four patterns of organic-rich shale and its roof and floor were summed up, and the rapid evaluation method of sealing of shale and its roof and floor under the limited geological data was established.Zhang, L., Lei, Q., Luo, J., Zeng, M., Wang, L., Huang, D., Wang, X., Mannan, S., Peng, B., Cheng, Z., 2019. Natural halloysites-based janus platelet surfactants for the formation of Pickering emulsion and enhanced oil recovery. Scientific Reports 9, Article 163. colloidal surfactants with opposing wettabilities are receiving attention for their practical application in industry. Combining the advantages of molecular surfactants and particle-stabilized Pickering emulsions, Janus colloidal surfactants generate remarkably stable emulsions. Here we report a straightforward and cost-efficient strategy to develop Janus nanoplate surfactants (JNPS) from an aluminosilicate nanoclay, halloysite, by stepwise surface modification, including an innovative selective surface modification step. Such colloidal surfactants are found to be able to stabilize Pickering emulsions of different oil/water systems. The microstructural characterization of solidified polystyrene emulsions indicates that the emulsion interface is evenly covered by JNPS. The phase behaviors of water/oil emulsion generated by these novel platelet surfactants were also investigated. Furthermore, we demonstrate the application of JNPS for enhanced oil recovery with a microfluidic flooding test, showing a dramatic increase of oil recovery ratio. This research provides important insights for the design and synthesis of two-dimensional Janus colloidal surfactants, which could be utilized in biomedical, food and mining industries, especially for circumstances where high salinity and high temperature are involved.Zhang, L., Peng, Y., Yang, J., 2019. Transformation of dissolved organic matter during advanced coal liquefaction wastewater treatment and analysis of its molecular characteristics. Science of The Total Environment 658, 1334-1343. liquefaction wastewater (CLW) contains numerous toxic and biorefractory organics. A series of advanced treatment processes were designed to remove the dissolved organic matter (DOM) from CLW. Here, the reactivity and state of the DOM in the treatment train were studied in relation to its chemical composition by a Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) analysis. Within an isobaric group, the raw CLW possessed a high average double-bond equivalent (DBEwa) and low H/Cwa values with the N- and S-containing compounds accounting for approximately 77% of the raw CLW, which represented lignin (73.6%) and condensed aromatic structures (19.8%). In addition, the flotation process removed some hydrophobic DOM compounds with highly unsaturated states, which were biorefractory compounds. Ozonation and catalytic oxidation processes preferentially removed the highly unsaturated compounds and produced more oxidized molecules. The biofiltration process impacted the organics composition by consuming oxygen-rich substances, whereas the anoxic/oxic (A/O) process converted the reactive compounds into newly formed compounds through the loss of hydrogen (unsaturation) from the original compounds. The membrane bioreactor (MBR) process was more efficient in removing the N-containing compounds with higher unsaturated states. The compounds resistant to the applied CLW treatment processes were characterized by lower molecular weights (approximately 250–350?Da), higher oxidation states (O/S?>?6), numerous carboxylic groups, and non-biodegradable features.Zhang, L., Zhang, L., Xu, Z., Guo, X., Xu, C., Zhao, S., 2018. Viscosity mixing rule and viscosity–temperature relationship estimation for oil sand bitumen vacuum residue and fractions. Energy & Fuels 33, 206-214. heavy components through solvent separation is a potential routine for the viscosity reduction of Canadian oil sand bitumen. The mixing rule for the viscosity of extracted fraction is the basis of process simulation and optimization. In this study, supercritical fluid extraction fractionation was applied to separate Canadian oil sand bitumen vacuum residue (VR) into various fractions. The viscosity blending behavior of extracted fractions was experimentally evaluated. Several available viscosity mixing rules were tested. To predict the viscosity–temperature profile of derived fractions at different blending ratio, we proposed a new mixing rule based on empirical equation parameters. We also correlated the viscosity–temperature parameters to conventional bulk property, providing a method for the rapid viscosity estimation for VR, extracted fractions, and their mixtures.Zhang, P., Liu, G., Cai, C., Li, M., Chen, R., Gao, P., Xu, C., Wan, W., Zhang, Y., Jiang, M., 2019. Alteration of solid bitumen by hydrothermal heating and thermochemical sulfate reduction in the Ediacaran and Cambrian dolomite reservoirs in the Central Sichuan Basin, SW China. Precambrian Research 321, 277-302. bitumen in reservoir rocks is an allochthonous organic matter formed from bitumen or liquid hydrocarbons by various alteration processes. In this study, two types of altered solid bitumen have been identified in both the Ediacaran Dengying and Cambrian Longwangmiao formations in the Central Sichuan Basin using petrographic, microthermometric, chemical, and isotopic data. The hydrothermally altered bitumen (type 1) is associated with the pore-filling saddle dolomite and quartz in which homogenization temperatures of some fluid inclusions are more than 10?°C higher than the maximum burial temperature of the Dengying Formation. It has various anisotropic textures with significantly high bireflectance values (Rbmax???Rbmin, %) between 3.89% and 9.21%. Moreover, the hydrothermal alteration led to 13C-enrichment in the type 1 bitumen compared to the normally matured bitumen derived from the same source. On the other hand, the thermochemical sulfate reduction (TSR)-altered bitumen (type 2) has S/C atomic ratios of up to approximately 0.06. The δ34S values of type 2 bitumen are close to those of the carbonate-associated sulfate and similar to the TSR-derived H2S in the same reservoirs. A strong negative correlation exists between S/C atomic ratios and δ13C values in the type 2 bitumen in the Dengying Formation, which is interpreted as a result of an increasing incorporation of the 13C-depleted ethanethiol into the bitumen during TSR. This interpretation is consistent with the fact that the remaining ethane became isotopically heavier as TSR proceeded. In addition, the reactive sulfate for TSR was primarily derived from the hydrothermal sulfate, such as barite. This is evidenced by the replacement of hydrothermal barite by the 34S-enriched pyrite and the small differences in δ34S value between the barite and the type 2 bitumen (or the TSR-derived H2S) in the same strata. We suggest that TSR in the Ediacaran and Cambrian hydrocarbon reservoirs was probably initiated by hydrothermal activity.Zhang, Q., Amor, K., Galer, S.J.G., Thompson, I., Porcelli, D., 2019. Using stable isotope fractionation factors to identify Cr(VI) reduction pathways: Metal-mineral-microbe interactions. Water Research 151, 98-109. interact with metals and minerals in the environment altering their physical and chemical states, whilst in turn metals and minerals impact on microbial growth, activity and survival. The interactions between bacteria and dissolved chromium in the presence of iron minerals, and their impact on Cr isotope variations, were investigated. Cr(VI) reduction experiments were conducted with two bacteria, Pseudomonas fluorescens LB 300 and Shewanella oneidensis MR-1, in the presence of two iron oxide minerals, goethite and hematite. Both minerals were found to inhibit the rates of Cr(VI) reduction by Pseudomonas, but accelerated those of Shewanella. The Cr isotopic fractionation factors generated by Shewanella were independent of the presence of the minerals (ε?=??2.3‰). For Pseudomonas, the ε value was the same in both the presence and absence of goethite (?3.3‰); although, it was much higher (ε?=??4.3‰) in the presence of hematite. The presence of aqueous Fe(III) in solution had no detectable impact on either bacterial Cr reduction rates nor isotopic fractionation factors. The presence of aqueous Fe(II) induced rapid abiotic reduction of Cr(VI). The different effects that the presence of Fe minerals had on the Cr fractionation factors and reduction rates of the different bacterial species may be attributed to the way each bacteria attached to the minerals and their different reduction pathways. SEM images confirmed that Pseudomonas cells were much more tightly packed on the mineral surfaces than were Shewanella. The images also confirmed that Shewanella oneidensis MR-1 produced nanowires. The results suggest that the dominant Cr(VI) reduction pathway for Pseudomonas fluorescens LB 300 may have been through membrane-bound enzymes, whilst for Shewanella oneidensis MR-1 it was probably via extracellular electron transfer. Since different minerals impact differentially on bacterial Cr(VI) reduction and isotope fractionation, variations of mineralogies and the associated changes of bacterial communities should be taken into consideration when using Cr isotopes to quantify Cr redox behaviour in the environment.Zhang, S., Wang, J., Liu, X., Qu, F., Wang, X., Wang, X., Li, Y., Sun, Y., 2019. Microplastics in the environment: A review of analytical methods, distribution, and biological effects. TrAC Trends in Analytical Chemistry 111, 62-72. (MP) (<5?mm) are crucial pollution which are widely distributes in the environment. Recently, the studies of MP have increased rapidly due to increasing awareness of the potential and growing risks of biological effects during storage and disposal. However, due to limitations in analytical methods and the methods of environmental risk assessment, the distribution and biological effects of MP are still debatable issues. To clarify the potentially environmental and biological impacts of MP in the consecutive environment, (1) analytical methods to assess MP, (2) environmental transportation and distribution of MP and (3) the effects of MP on biota, including the additives and sorption-desorption of MP in both terrestrial ecosystem and aquatic ecosystems were summarized. Based on the reviewed publications, we propose considerations for addressing the insufficiencies of analytical methods, distribution and biological effects of MP in ecosystems so we can adequately safeguard global ecosystems.Zhang, X., Gao, Y., Chen, X., Hu, D., Li, M., Wang, C., Shen, Y., 2019. Nitrogen isotopic composition of sediments from the eastern Tethys during Oceanic Anoxic Event 2. Palaeogeography, Palaeoclimatology, Palaeoecology 515, 123-133. nitrogen isotopic compositions (δ15N) have been reported in deposits from the proto-North Atlantic and western Tethys during Oceanic Anoxic Event 2 (OAE2) at the Cenomanian-Turonian (C-T) transition. It has been proposed that the low δ15N values may have resulted from enhancement of N2 fixation and/or incomplete assimilation of the upwelled ammonium due to expansion of anoxic/euxinic conditions. However, few δ15N measurements are available for the sediments from the eastern Tethys and the Pacific and therefore the global significance of the N cycle and its environmental implications remains to be tested. Here, we present δ15N data from OAE2 deposits in the Gongzha section in the Tingri area of southern Tibet, which was located on the southern margin of the eastern Tethys during the mid-Cretaceous. The δ15N data reveal a large perturbation of the N cycle during OAE2. The pronounced negative shift in δ15N prior to OAE2, as well as the persistent low δ15N values during OAE2, imply the significant contribution of N2 fixation. The changes in the marine N cycle suggest that the expansion of an anoxic environment may also have occurred in the southern continental margin areas of eastern Tethys. The coincidence of the marine faunal turnover and the perturbation of the N cycle suggests that the expansion of anoxic water masses may have played an important role in the extinction of marine organisms across the C-T boundary in eastern Tethys.Zhang, X., Jiang, X., Wang, X., Zhao, Y., Jia, L., Chen, F., Yin, R., Han, F., 2019. A metabolomic study based on accurate mass and isotopic fine structures by dual mode combined-FT-ICR-MS to explore the effects of Rhodiola crenulata extract on Alzheimer disease in rats. Journal of Pharmaceutical and Biomedical Analysis 166, 347-356. metabolomic strategy based on accurate mass and isotopic fine structures (IFSs) by dual mode combined-Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) was established to explore the effects of Rhodiola crenulata extract (RCE) on Alzheimer disease (AD) in rats. Experimental AD model was induced in rats by bilateral hippocampal injection of Aβ1-42, and Morris water maze task (MWM) was used to evaluate the effects of RCE on AD. Subsequently, the metabolomic study was performed using HPLC-FT-ICR-MS, fraction collector and direct infusion (DI)-FT-ICR-MS to screen and identify the potential biomarkers. A total of 20 metabolites contributing to AD progress were decisively identified, and 17 metabolites of them were restored to the control-like levels after RCE treatment (daily dose: 2.24?g/kg). The metabolic pathway analysis revealed that the disturbed pathways including tryptophan metabolism, sphingolipid metabolism and glycerophospholipid metabolism in AD model rats were regulated after high dose RCE application. It is the first time that the dual mode combined-FT-ICR-MS based metabolomic strategy was applied to biochemically profile the serum metabolic pathways of AD rats affected by RCE. These outcomes provide reliable evidence to illuminate the biochemical mechanisms of AD and facilitate investigation of the therapeutic benefits of RCE in AD treatment. Notably, it indicated that the developed method based on accurate mass and IFSs has sufficient performance for decisive identification of biomarkers in metabolomic studies.Zhang, X., Zou, C., Zhao, J., Li, N., Zhang, S., Kouamelan, K.S., Xiao, L., Ma, H., Niu, Y., 2019. Organic-rich source rock characterization and evaluation of the Cretaceous Qingshankou Formation: results from geophysical logs of the second scientific drilling borehole in the Songliao Basin, NE China. Geosciences Journal 23, 119-135. second continental scientific drilling (SKII east) borehole in the Songliao Basin has been planned to be the deepest borehole to drill through the Cretaceous continental strata under the framework of the International Continental Scientific Drilling Program (ICDP) up to date. This borehole was designed not only to explore the potential relationships between dinosaur extinction and climate environment during the Cretaceous but also to achieve new breakthroughs in oil and gas exploration. The high hydrocarbon (oil and gas) potential of a source rock is highly dependent on its organic content. We used geophysical log data of Borehole SKII east to evaluate the organic content of organic-rich source rock. In the period of the first member in the Qingshankou Formation (K2qn1) from the study area, high accommodation space and anoxic environment could promote organic matter deposition. Firstly, based on geological information and abundant geophysical log data, the basic geophysical characteristics (including petrophysical, lithological, mineralogical, and sedimentary properties) of the Qingshankou Formation in Borehole SKII east were studied. Secondly, geophysical log response characteristics (including resistivity, porosity, radioactivity, mineral and element) of organic-rich source rocks were analyzed. Thirdly, we tried to obtain suitable methods to predict total organic carbon (TOC) content of the target formation with geophysical log data. The laboratorymeasured TOC values of core samples from Borehole SKI south were used to make calibrations with calculated TOC values from geophysical logs. Results from improved ΔlogR technique and Dual_Vsh method are consistent, and indicate that these two methods are effective in this formation. The calculated TOC values from these two methods are relatively desirable, and show that the organic-rich source rocks with high TOC content occurred in the K2qn1 (1646.00~1669.00 m). The highest TOC content can reach 9.15%. The bed thicknesses of organic-rich source rocks are totally up to 7.88 m. These organic-rich source rocks can be considered as excellent. This study demonstrated that improve ΔlogR technique can be applied to evaluate source rocks in the formations without maturity data, and the new method Dual_Vsh is also valid in the Qingshankou Formation. The organic-rich source rock evaluation results could promote further exploration and development of oil and gas resources in the upper Cretaceous formations, Songliao Basin.Zhang, Y.-Y., Wei, X.-Y., Lv, J.-H., Jiang, H., Liu, F.-J., Liu, G.-H., Zong, Z.-M., 2019. Identification of oxygen-containing aromatics in soluble portions from thermal dissolution and alkanolyses of Baiyinhua lignite. Fuel Processing Technology 186, 149-155. lignite (BL) was sequentially treated in cyclohexane, CH3OH, CH3CH2OH, and (CH3)2CHOH at 300?°C to afford soluble portions (SPs) 1–4 (SP1–SP4), which were analyzed with a Fourier transform infrared spectrometer, gas chromatograph/mass spectrometer (GC/MS), and quadrupole exactive orbitrap mass spectrometer (QEOTMS) with atmosphere pressure chemical ionization source in negative-ion mode. In addition, it was characterized with a solid-state 13C nuclear magnetic resonance and X-ray photoelectron spectrometer (XRPES). The results show that aliphatic and aromatic carbons, accounting for 37.1% and 59.2%, respectively, are dominated in BL. Each aromatic cluster contains 2 rings on average with 3 substituent groups on each ring. According to the analysis with XRPES, –OH group is the most abundant existing form of oxygen in BL. The analysis with GC/MS shows that the most abundant group components are arenols in SP1 and SP2, and alkanoates in SP3. Thousands of oxygen-containing aromatics (OCAs) were resolved with the QEOTMS and the molecular masses are mainly in the range of 250–400?μ. The main OCAs detected are O1–O6 class species, dominated by O2–O5 class species, which could be mainly assigned to acidic species, such as alkylarenediols, alkylarenetriols, and alkylarenoic acids.Zhang, Y., Arya, A., Kontogeorgis, G., Yarranton, H., 2019. Modeling the phase behaviour of bitumen/n-alkane systems with the cubic plus association (CPA) equation of state. Fluid Phase Equilibria 486, 119-138. cubic-plus-association equation of state was applied to model the phase behaviour of bitumen/n-alkane systems including saturation pressures, liquid-liquid boundaries, yields, and phase compositions. Yield is defined here as the mass of bitumen in the heavy phase divided by the mass of bitumen in the feed. To implement the model, the bitumen was divided into a set of pseudo-components based on a distillation assay and either the n-pentane insoluble content of the oil (CPA-C5 approach) or the propane insoluble content (CPA-C3 approach). The pseudo-components in the solvent insoluble part of the oil were defined as self-associating components, all other pseudo-components were non-associating. The critical properties and acentric factor for each pseudo-component were determined from established correlations. A set of CPA parameters was then developed to fit the available phase behavior data. The self-associating pseudo-components were assigned a distribution of self-association energies in order to capture the sequential partitioning of asphaltenes to the heavy phase upon solvent addition or in different solvents. Both approaches matched the phase behavior data for mixtures of bitumen with n-pentane and higher carbon number n-alkanes almost to within the experimental error. The CPA-C3 approach also matched the phase behavior data for mixtures of propane and bitumen. The CPA-C5 approach could not match the yield data for propane diluted bitumen but was more straightforward to implement and was less computationally intensive because it employed fewer self-associating components. To apply either approach to another oil, only the self-association energy of the self-associating pseudo-components need be adjusted. The cross-association energy between the solvent and the self-associating pseudo-components must be tuned for any new solvent.Zhang, Y., Gao, M., You, Q., Fan, H., Li, W., Liu, Y., Fang, J., Zhao, G., Jin, Z., Dai, C., 2019. Smart mobility control agent for enhanced oil recovery during CO2 flooding in ultra-low permeability reservoirs. Fuel 241, 442-450. development of natural/artificial fractures leads to significant differences of the physical properties between the matrix and the fractures, which usually causes serious channeling and low sweep efficiency during CO2 flooding in ultra-low permeability reservoirs, the use of a CO2-responsive smart mobility control system to generate bulk gel by wormlike micelles (WLMs) to mitigate gas channeling has great potentials for enhanced oil recovery (EOR) in ultra-low permeability reservoirs. In this study, five kinds of chemicals with CO2-sensitive groups are screened to measure the apparent viscosity using a rheometer. The experimental results show that the optimum system consists of 4.4?wt%?N, N-dimethyl octylamide-propyl tertiary amine (DOAPA) and 2.0?wt% sodium p-toluenesulfonate (SPTS). Subsequently, the plugging capacity and EOR performance of the system are systematically evaluated using core flooding experiments. The optimized system (DOAPA/SPTS) exhibits outstanding plugging capacity for gas channeling with a plugging efficiency of 99.2%. The oil recovery of the CO2 flooding increases by 20.0%. In addition, the thickening mechanism of the CO2-responsive system is studied using rheological experiments and a cryogenic transmission electron microscopy (Cryo-TEM). The shear-thinning behavior demonstrates that the thickening effect of the high-viscosity WLMs is strong in the DOAPA/SPTS-CO2 solution, and the Cryo-TEM results indicate a transition from spherical micelles to the WLMs. The protonation contributes to the formation of the WLMs in the solution during phase transformation process. The results of this study are expected to provide benchmark to select the mobility control agent for CO2 flooding in ultra-low permeability reservoirs.Zhang, Y., Zhang, Y., Xiong, J., Zhao, Z., Chai, T., 2019. The enhancement of pyridine degradation by Rhodococcus KDPy1 in coking wastewater. FEMS Microbiology Letters 366, Article fny271. is a typical nitrogen heterocyclic and recalcitrant organic compound in coking wastewater. The pyridine-degrading bacterial strain KDPy1 was isolated from aerobic sludge in a coking wastewater treatment plant. The homology analysis based on 16S rDNA sequences suggested that KDPy1 belongs to Rhodococcus sp. The optimum temperature and pH for pyridine degradation by KDPy1 were 37°C and 7–8, respectively. The strain KDPy1 degraded 1442 mg/L of pyridine nearly 99.6% after 48 h, and the high concentration of 1442 mg/L pyridine did not show an inhibitory effect on its degradation. The degradation kinetics of pyridine were fitted with the Monod model. Furthermore, KDPy1 was capable of degrading pyridine efficiently in the synthetic wastewater containing quinoline and phenol. KDPy1 could degrade pyridine and reduce the total organic carbon in the real coking wastewater. These results showed that KDPy1 had a potential for improving the removal of pyridine from coking wastewater.Zhao, B., Yao, P., Bianchi, T.S., Shields, M.R., Cui, X.Q., Zhang, X.W., Huang, X.Y., Schr?eder, C., Zhao, J., Yu, Z.G., 2018. The role of reactive iron in the preservation of terrestrial organic carbon in estuarine sediments. Journal of Geophysical Research: Biogeosciences 123, 3556-3569. better understand the role of reactive Fe (FeR) in the preservation of sedimentary organic carbon (SOC) in estuarine sediments, we examined specific surface area, grain size composition, total OC (TOC), lignin phenols, FeR, FeR‐associated OC (Fe‐OC) and lignin phenols (Fe‐lignin), and δ13C of FeR‐associated OC (δ13CFe‐OC) in surface sediments of the Changjiang Estuary and adjacent shelf. An estimated 7.4 ± 3.5% of the OC was directly bound with FeR in the Changjiang Estuary and adjacent shelf. Unusually low TOC/specific surface area loadings and Fe‐OC/Fe ratios in mobile muds suggest that frequent physical reworking may reduce FeR binding with OC, with selective loss of marine OC. More depleted 13CFe‐OC relative to 13C of TOC (13Cbulk) in deltaic regions and mobile muds showed that FeR was largely associated with terrestrial OC, derived from extensive riverine OC and Fe inputs. A higher proportion of hematite in the mobile muds compared to the offshore samples indicated that Fe oxides are likely subjected to selective sorting and/or become mature during long‐term sediment transport. When considering the percentage of Fe‐OC to SOC and SOC burial rates in different marine environments (e.g., nondeltaic shelf, anoxic basins, slope, and deep sea), our findings suggest that about 15.6 ± 6.5% of SOC is directly bound to FeR on a global scale, which is lower than the previous estimation (~21.5%). This work further supports the notion of a Rusty Sink where, in this case, FeR plays an important role in the preservation and potential transport of terrestrial OC in the marine environment.Zhao, J., Ye, Q., Wang, P., 2019. Optimization of stepped collision energies of HCD in Orbitrap mass spectrometry for metabolite structure elucidation. Drug Metabolism and Pharmacokinetics 34, S38-S39. higher-energy collisional dissociation (HCD) technique has been employed to enhance the fragmentation efficiency of peptides in protein identification1, 2, and to provide more specific structural information of small molecules less than 600 Da3. Thermo’s Q Exactive Plus, a hybrid quadrupole-orbitrap mass spectrometer, allows collection of fragmentation ions using stepped collision energy scans, in which same precursor is injected into the HCD cell several times at different collision energies (CE). This research describes a generic QE Plus method workflow utilizing MS method with fifteen parallel-reaction monitoring (PRM) scan events, in which collision energies varied from 10 to 150%, to optimize the CE energy parameters for different parent compound and its metabolites. Target compound (or mixture of several target compounds) can be analyzed using this method by direct MS acquisition, along with fifteen times of HPLC loop injections for 30 seconds each. All MS/MS (MS2) spectra at different CEs were acquired into one data file in about 10 minutes, which was then used to select the best combination of CEs for targeted compound(s). Two commercially available chemicals and their metabolites (midazolam and metabolite 1'-hyrdoxymidazolam, and diclofenac and metabolite 4'-hydroxydiclofenac) were analyzed using this method on QE Plus. Fragment ions at high mass for midazolam and 1'-hyrdoxymidazolam were observed starting at CE= 40, while more low mass fragment ions were observed starting at CE=90. For diclofenac and 4'-hydroxydiclofenac, more informative fragment ions were observed when stepped CE was set at 10 for high mass, and 110 for low mass. There was no big difference of MS2 pattern when CE was between 30 and 100 for diclofenac and its metabolite. Based on these results, the combination of three stepped normalized collision energies of 50, 70, and 90 (average 70) were applied to obtain the MS/MS fragment ions of 1'-hyrdoxymidazolam, and CE=10, 70, and 130 (average 70) were used for 4'-hydroxydiclofenac. A comprehensive MS2 spectrum was generated, utilizing three different CEs at the same time, and complexing three spectra into one spectrum. In conclusion, optimization of the CEs using the generic streamlined method facilitated to find the sweet combination of three stepped collision energies for parent compound and its putative metabolites. The complexed HCD MS2 spectrum with three optimized CEs, provided more fragmentation information comparing to that with a single CE or three randomly selected CEs, when used for the elucidation of chemical structure, and determination of metabolism site.Zhao, P., Wang, X., Cai, J., Luo, M., Zhang, J., Liu, Y., Rabiei, M., Li, C., 2019. Multifractal analysis of pore structure of Middle Bakken formation using low temperature N2 adsorption and NMR measurements. Journal of Petroleum Science and Engineering 176, 312-320. the complexity and heterogeneity of pore structure can improve the comprehensive characterization for complex unconventional reservoirs and better exploit those resources. In this paper, multifractal analysis was conducted on low temperature N2 adsorption and NMR T2 distribution for the pore structure investigation in Middle Bakken formation in Williston Basin, USA. Results show that the averages of specific surface area, total pore volume, the average pore size of five N2 adsorption samples are 3.31?m2/g, 0.008?cm3/g, and 19.57?nm, respectively. Six NMR T2 distributions are bimodal and the signals of left dominant peaks are mainly distributed between 0.3?ms and 10?ms. The T2 logarithmic mean value ranges from 2.18?ms to 2.95?ms with an average value of 2.57?ms. Both N2 adsorption isotherms and T2 distribution demonstrated the multifractal nature of different pore sizes. The key multifractal parameter, singularity strength range (Δα) calculated from N2 adsorption and T2 distribution are respectively distributed in scopes of 0.72–1.54 and 1.63–2.89, indicating that the heterogeneity of pore space from T2 distribution is stronger than that from N2 adsorption. It was observed that the specific surface, micro pore volume, and average pore size are correlated well with Δα. There are no any correlations between Δα and porosity and T2 lm, but the cumulative porosity and width of right secondary peaks have an impact on the Δα, which means that the heterogeneity difference between the two methods is attributed by larger pore and micro fractures.Zhao, S., Shao, L., Hou, H., Tang, Y., Li, Z., Yao, M., Zhang, J., 2018. Methane adsorption characteristics and its influencing factors of the medium-to-high rank coals in the Anyang-Hebi coalfield, northern China. Energy Exploration & Exploitation 37, 60-82. variation of coal rank in the Anyang-Hebi (Anhe) coalfield has the phenomenon of anti-Hilt law, which makes the coalfield distinctive for coalbed methane exploration research. The methane adsorption characteristics and influencing factors of the medium-to-high rank coal samples of the Shanxi Formation in this coalfield were analyzed. The results indicate that the Langmuir volume (VL) of coals in the shallow western part of the Anhe coalfield is generally higher than that in the deep eastern part. The coal rank and the coal macerals are the dominant factors that influence the methane adsorption capacity of coals in this anti-Hilt law area. The methane adsorption capacity, represented by VL, first increases and then decreases with the coal rank, and the highest VL value corresponds to the maximum vitrinite reflectance of ～2.1%. The adsorption capacity has a positive correlation with the vitrinite and the moisture content, a negative relationship with the inertinite content. In general, the adsorption capacity of coal samples shows a “V-shaped” change with the ash yield, and the lowest VL value corresponds to the ash yield of ～9%. A prediction model of the gas content of the Anhe coalfield was proposed based on changes of the methane adsorption capacity and principal component analysis. Areas with a critical depth ranging from 400 m to 700 m are suggested to be methane enrichment regions for coalbed methane exploration in the Anhe coalfield.Zhao, X., Sun, Y., Deng, J., Rao, Z., Lü, C., Song, J., Li, L., 2018. Microbial gas in the Mohe permafrost, northeast China and its significance to gas hydrate accumulation in permafrost across China. Acta Geologica Sinica - English Edition 92, 2251-2266. Mohe permafrost in northeast China possesses favorable subsurface ambient temperature, salinity, Eh values and pH levels of groundwater for the formation of microbial gas, and the Mohe Basin contains rich organic matter in the Middle Jurassic dark mudstones. This work conducted gas chromatography and isotope mass spectrometry analyses of nearly 90 core gas samples from the Mk‐2 well in the Mohe Basin. The results show that the dryness coefficient (C1/C1–5) of core hydrocarbon gas from approximately 900 m intervals below the surface is larger than 98%, over 70% of the δ13C values of methane are smaller than –55‰, and almost all δD values of methane are smaller than –250‰, indicative of a microbial origin of the gas from almost 900 m of the upper intervals in the Mohe permafrost. Moreover, the biomarker analyses of 72 mudstone samples from the Mohe area indicate that all of them contain 25‐norhopane series compounds, thereby suggesting widely distributed microbial activities in the permafrost. This work has confirmed the prevailing existence of microbial gas in the Mohe area, which may be a potential gas source of gas hydrate formation in the Mohe permafrost. This result is of great significance to gas hydrate accumulation in the permafrost across China.Zhao, X., Zhou, L., Pu, X., Han, W., Jin, F., Xiao, D., Shi, Z., Deng, Y., Zhang, W., Jiang, W., 2019. Exploration breakthroughs and geological characteristics of continental shale oil: A case study of the Kongdian Formation in the Cangdong Sag, China. Marine and Petroleum Geology 102, 544-556. geology and deposition features of the fine grain phase region in the second member of the Kongdian Formation were investigated using traditional petroleum geology and sedimentary petrology. New theories for shale oil and gas formation, based on data from 500?m continuous coring, systematic analysis of over ten thousand core samples, and logging data in the center of the lake basin in the Cangdong Sag (Bohai Bay Basin, China) were developed to determine the distribution of shale oil and provide a basis for shale oil exploration deployment. Results showed that a wide distribution of semi-deep to deep lake sub-facies fine-grained sediment (shale) was deposited in the study area during the largest lake flooding period. This sediment consists of felsic shale, mixed shale, and dolomites, but no clay shale. The shale features multiple rock components with few dominant minerals; high clastic mineral content and low clay mineral content; rich analcite and lean pyrite; rich brittle minerals with lean quartz; diverse rock types with limited shale oil; more tight reservoirs and fewer reservoirs with no fractures; more high-quality source rock with less non-hydrocarbon source rock; and more high frequency cycles with fewer monolithic deposits. Results indicate that dolomites are located in strips on the plane and are locally enriched, contradicting the understanding that only hydrocarbon source rock, and no reservoirs, develop in the middle of a continental closed lake basin. The study region demonstrates good conditions for shale oil formation, a favorable configuration of source rock and reservoirs, and 260?km2 of sweet spots, indicating high exploration value. Several prospecting wells have obtained industrial oil flow with guidance based on geological knowledge and engineering technology support.Zhao, Y.-l., Wang, Z.-m., 2019. Multi-scale analysis on coal permeability using the lattice Boltzmann method. Journal of Petroleum Science and Engineering 174, 1269-1278. a mesoscopic kinetic approach, the lattice Boltzmann method (LBM) has been widely applied to characterize the flows in porous medium. However, for larger scale flows, upscaling microscale technique is the key and difficult point. Based on the X-ray computed tomography (X-CT) images of actual coal samples, numerical simulations were carried out using the LBM at the pore scale. The velocity/pressure distribution and coal permeability were obtained. The local rate of mechanical dissipation is applied to determine an appropriate representative elementary volume (REV) scale. Then based on a gray lattice Boltzmann model, numerical simulations were carried at the REV scale and the pressure distribution is almost identical with the solution of the LBM simulations at the pore scale. The simulation results of REV with different sizes indicate that the size of REV determined in this paper is reasonable. The relative errors between the pore scale and REV scale simulation for permeability prediction are less than 6%. In addition, the REV scale simulation can greatly improve the computational efficiency and provides an effective approach for large-scale flow simulation.Zhao, Y., Peng, L., Liu, S., Cao, B., Sun, Y., Hou, B., 2019. Pore structure characterization of shales using synchrotron SAXS and NMR cryoporometry. Marine and Petroleum Geology 102, 116-125. characterization of shale pore structure is extremely important to shale gas exploitation. Various techniques have been employed to characterize the pore size distribution (PSD) in shales. Small angle X-ray scattering (SAXS) is a relatively new technique that can be applied to obtain the PSD of porous materials. However, little work has been done on shales by synchrotron SAXS. In this paper, scanning electronic microscopy (SEM), nuclear magnetic resonance cryoporometry (NMRC), and synchrotron small-angle X-ray scattering (SAXS) were used to comprehensively characterize pore structure in three shales with a total organic carbon content of 0.68%, 3.68% and 4.3%. The processing and postprocessing for synchrotron SAXS data were executed. Based on background deduction, a positive deviation correction of SAXS data was conducted. SEM was combined with synchrotron SAXS to explore whether the sample is a single dispersion. Two models (Gauss distribution model and the maximum entropy model) for calculating the PSD by synchrotron SAXS were compared with the results by NMRC. The PSD from the Gauss distribution presents good consistency with the PSD from the NMRC with a diameter of less than 15?nm. Notably, a PSD obtained by maximum entropy model and NMRC is more consistent for pores with a diameter of 15–48?nm. Nanopore structure was also explored and discussed based on the Porod theory. Methods for quantitative characterization of pore size proposed in this paper are applicable to other two-phase rock media.Zhegallo, E.A., Zaytseva, L.V., Orleansky, V.K., Samylina, O.S., Karpov, G.A., 2018. Traits of biomorphic structure formation in Kamchatka geyserites. Paleontological Journal 52, 1172-1178. of silicic rocks shaped by the activity of thermophilic bacterial communities in active volcanism areas of Kamchatka are described in the present article. The role of microorganisms as a special matrix that accelerates the formation of microlayered rocks of mixed chemogenic and biogenic origin is demonstrated. The authors suggest the term “biosilicites” for such rocks.Zhou, X., Sun, H., Pumpanen, J., Sieti?, O.-M., Heinonsalo, J., K?ster, K., Berninger, F., 2019. The impact of wildfire on microbial C:N:P stoichiometry and the fungal-to-bacterial ratio in permafrost soil. Biogeochemistry 142, 1-17. thaw near-surface permafrost soils in the boreal forest, making previously frozen organic matter available to microbes. The short-term microbial stoichiometric dynamics following a wildfire are critical to understanding the soil element variations in thawing permafrost. Thus, we selected a boreal wildfire chronosequence in a region of continuous permafrost, where the last wildfire occurred 3, 25, 46, and >?100?years ago (set as the control) to explore the impact of wildfire on the soil chemistry, soil microbial stoichiometry, and the fungal-to-bacterial gene ratio (F:B ratio). We observed the microbial biomass C:N:P ratio remained constant in distinct age classes indicating that microbes are homeostatic in relation to stoichiometric ratios. The microbial C:N ratios were independent of the shifts in the fungal-to-bacterial ratio when C:N exceeded 12. Wildfire-induced reduction in vegetation biomass positively affected the fungal, but not the bacterial, gene copy number. The decline in microbial biomass C, N, and P following a fire, primarily resulted from a lack of soil available C and nutrients. Wildfire affected neither the microbial biomass nor the F:B ratios at a soil depth of 30?cm. We conclude that microbial stoichiometry does not always respond to changes in the fungal-to-bacterial ratio and that wildfire-induced permafrost thawing does not accelerate microbial respiration.Zhu, B., Henneberger, R., Weissert, H., Zeyer, J., Schroth, M.H., 2018. Occurrence and origin of methane entrapped in sediments and rocks of a calcareous, alpine glacial catchment. Journal of Geophysical Research: Biogeosciences 123, 3633-3648. ecosystems are an important indicator of climate change, and dynamics of the greenhouse gas methane (CH4) in these systems has become a major research topic of late. We investigated occurrence and origin of recently discovered, sediment‐entrapped CH4 within the Wildstrubel glacial catchment (Switzerland) using geochemical analyses on gas extracted from sediments and rocks, including gas content and CH4 stable isotope measurements, and computation of gas wetness (ratio of CH4 to ethane and propane). We also examined the potential occurrence of microbial CH4 production in subglacial, supraglacial, and glacier forefield sediments based on molecular analyses targeting mcrA (a marker gene for microbial CH4 production) and based on observed CH4 production during laboratory incubation experiments. Substantial amounts of entrapped CH4 were detected in all sediment (65.7 ± 28.6 μg CH4/g) and most rock samples (up to 145.5 μg CH4/g). Similar gas wetness (0.7–126.7) and CH4 stable isotope values (δ13CCH4: ?26.9‰ to ?31.2‰, δDCH4: ?118.5‰ to ?158.6‰) in sediment and rock samples provided strong evidence that entrapped CH4 was of common, thermogenic origin. Molecular analyses (up to ~105 mcrA gene copies per gram) and laboratory incubation experiments (production rates up to 1.55 CH4 g?1 day?1) provided evidence for local hot spots of viable methanogens in waterlogged, glacier forefield sediments but not in subglacial sediments. Nonetheless, microbial CH4 production appeared to be only of minor importance at our field site, as indicated by results of our geochemical analyses. Our findings illustrate the crucial importance of appropriate geochemical analyses to provide solid evidence on the origin of CH4 in glacial systems.Zhu, H., Ju, Y., Huang, C., Han, K., Qi, Y., Shi, M., Yu, K., Feng, H., Li, W., Ju, L., Qian, J., 2019. Pore structure variations across structural deformation of Silurian Longmaxi Shale: An example from the Chuandong Thrust-Fold Belt. Fuel 241, 914-932. types and pore size vary systematically across structural deformation in the shale gas reservoirs but lack a comprehensive study. Twelve Longmaxi Shale samples spanning a tectonism range from undeformed to deformed were formed in the structural deformation zone located in a field section of the Chuandong Thrust-Fold Belt, South China. Herein, pore structure investigations are performed using three types of organic-rich shale (undeformed shale, fault-related shale, and fold-related shale) with vitrinite reflectance (Ro value) ranging between 1.90 and 2.57% and total organic carbon (TOC) content ranging between 2.25 and 4.40%. Compared to the undeformed shales, deformed samples are quartz rich and carbonate poor. Total porosity from mercury intrusion porosimetry (MIP) ranges between 3.74 and 5.62% in undeformed shales, 2.66–6.83% in fold-related shales, and 2.55–13.92% in fault-related shales. Scanning electron microscopy (SEM) study of the pore type evolution reveals organic matter (OM) pores are dominant in undeformed shales whereas the interparticle (interP) pores, intraparticle (intraP) pores, micro-channels, and micro-fractures are more developed in both fold- and fault-related shales. A combination of low-pressure gas (N2 and CO2) adsorption and MIP techniques suggests that with increasing structural deformation, micropore volumes relatively increase in fold-related samples, while macropore volumes significantly increase in fault-related shales. These observations and experiments confirm that tectonism produces an open and interconnected pore network within organic-rich shale, which is not related to OM pores. The role of structural deformation during ductile folding and brittle sliding, both in changing the mineral composition and in the producing process of the new pore networks, may be critical to understanding tectonism on organic-rich shales. These data could provide important theoretical guidance and scientific basis for the exploration and development of shale gas and resources assessment in the complex tectonic area of South China.Zhu, X., Rice, S.A., Barraud, N., 2019. Nitric oxide and iron signaling cues have opposing effects on biofilm development in Pseudomonas aeruginosa. Applied and Environmental Microbiology 85, Article e02175-18.: While both iron and nitric oxide (NO) are redox-active environmental signals shown to regulate biofilm development, their interaction and roles in regulating biofilms have not been fully elucidated. In this study, exposure of Pseudomonas aeruginosa biofilms to exogenous NO inhibited the expression of iron acquisition-related genes and the production of the siderophore pyoverdine. Furthermore, supplementation of the culture medium with high levels of iron (100?μM) counteracted NO-induced biofilm dispersal by promoting the rapid attachment of planktonic cells. In the presence of iron, biofilms were found to disperse transiently to NO, while the freshly dispersed cells reattached rapidly within 15?min. This effect was not due to the scavenging of NO by free iron but involved a cellular response induced by iron that led to the elevated production of the exopolysaccharide Psl. Interestingly, most Psl remained on the substratum after treatment with NO, suggesting that dispersal involved changes in the interactions between Psl and P. aeruginosa cells. Taken together, our results suggest that iron and NO regulate biofilm development via different pathways, both of which include the regulation of Psl-mediated attachment. Moreover, the addition of an iron chelator worked synergistically with NO in the dispersal of biofilms.Importance: Nitric oxide (NO), which induces biofilm dispersal, is a promising strategy for biofilm control in both clinical and industrial contexts. However, competing environmental signals may reduce the efficacy of NO. The results presented here suggest that the presence of iron represents one such environmental cue that antagonizes the activity of NO as a biofilm-dispersing agent. Based on this understanding, we developed a strategy to enhance dispersal by combining NO with an iron-scavenging agent. Overall, this study links two important environmental signals, iron and NO, with their roles in biofilm development and suggests new ways for improving the use of NO in biofilm control strategies.Zhuang, G.-C., Montgomery, A., Joye, S.B., 2019. Heterotrophic metabolism of C1 and C2 low molecular weight compounds in northern Gulf of Mexico sediments: Controlling factors and implications for organic carbon degradation. Geochimica et Cosmochimica Acta 247, 243-260. molecular weight (LMW) compounds are key intermediates in organic matter degradation and their metabolism supports a diverse microbial community in anoxic sediments. Much remains to be learned about the metabolic pathways and turnover rates of LMW compounds as well as the factors that influence their metabolism in the environment. We studied the microbial metabolism of acetate, methanol and methylamine in sediments from Northern Gulf of Mexico to elucidate their role as energy and carbon sources for microorganisms mediating terminal metabolic processes and to constrain the importance of C1 and C2 metabolism in the sedimentary carbon cycle. In terms of carbon flow, methanogenesis was a minor process in sulfate-rich sediments; acetate and methanol were oxidized primarily by non-methanogenic heterotrophs as an energy source. A large fraction of utilized acetate (20–76%) was assimilated into biomass, suggesting that acetate was a significant biomass-building source. In situ thermodynamic calculations suggested the utilization of acetate and methanol by sulfate-reducing bacteria was more favorable than the utilization by methanogens, consistent with the observed higher oxidation rates than methanogenesis rates as well as results from inhibitor experiments employing 2-bromoethanesulfonate and molybdate. Methylamine, by contrast, was utilized for methane production (up to 100%), but its utilization was not limited to methanogens. At an organic-poor deep-sea site, elevated acetate and methanol oxidation rates in the absence of sulfate-reducing and methanogenic activity indicated that metabolism of LMW compounds was coupled to other electron accepting processes, such as denitrification. Heterotrophic carbon assimilation was an important pathway for generating biomass at this site, as evidenced by comparable rates of acetate assimilation to bicarbonate incorporation. The oxidation and assimilation rates of LMW compounds generally decreased with sediment depth, following the trend of organic carbon degradation rates. Environmental factor, such as temperature but not pressure, affected the metabolism of LMW compounds; the oxidation of acetate, methanol and methylamine exhibited distinct responses to changes in temperature. In seep sediments, the oxidation of acetate and methanol accounted for 5% and 0.9%, respectively, of the total organic carbon oxidation. Collectively, this assessment of C1 and C2 LMW compound utilization shows that these compounds serve as energetic substrates to fuel methanogens, sulfate reducers and other microbes.Zoccali, M., Tranchida, P.Q., Mondello, L., 2019. On-line liquid chromatography-comprehensive two dimensional gas chromatography with dual detection for the analysis of mineral oil and synthetic hydrocarbons in cosmetic lip care products. Analytica Chimica Acta 1048, 221-226. on-line liquid chromatography-comprehensive two-dimensional gas chromatography (LC-GC×GC) separation process, combined with a dual detection system, namely triple quadrupole mass spectrometry (used as a single quadrupole - QMS) and flame ionization detection (FID), was developed for the analysis of cosmetic lip care products. The LC step was carried out by using a fused-core silica column, with this enabling the separation of mineral oil saturated hydrocarbons (MOSH), as well as polyolefin oligomeric saturated hydrocarbons (POSH), from the mineral oil aromatic hydrocarbon (MOAH) families. Each chemical class was then subjected to GC×GC-QMS/FID analysis, using a medium polarity-low polarity column combination. Notwithstanding the utility of the flame ionization detector for quantification purposes, it is obviously also desirable to obtain information on the type of hydrocarbons present (of mineral or synthetic origin), in order to identify a potential contamination source. Following method optimization, various analytical figures of merit (method linearity, intra- and inter-day repeatability, limits of detection and quantification, and injector discrimination) were measured. Specifically, for MOSH and MOAH, linearities were evaluated in the 32.5–2080 and 50–500?mg?L?1 range, respectively; furthermore, intra- and inter-day repeatability values were 6.2 and 8.3%, respectively, while limits of detection and quantification were 3.5 and 11.8?mg?L?1, respectively. The proposed method, enables for the first time (to the best of the authors’ knowledge), the detailed qualitative and quantitative analysis of saturated and aromatic hydrocarbons, in a single run and in a fully-automated manner. Quantities of MOSH?+?POSH in the cosmetic products ranged from 8.7 to 44.4% (CV values were in the 1.5–5.4% range) while MOAH contamination was found in four samples, ranging from 386 to 5869?mg?kg?1?(CV values were in the 0.5–4.5% range).Zuo, F., Heimhofer, U., Huck, S., Adatte, T., Erbacher, J., Bodin, S., 2019. Climatic fluctuations and seasonality during the Kimmeridgian (Late Jurassic): Stable isotope and clay mineralogical data from the Lower Saxony Basin, Northern Germany. Palaeogeography, Palaeoclimatology, Palaeoecology 517, 1-15. previous palaeoclimatic models, the Kimmeridgian stage has been defined as a typical greenhouse-time interval with weak latitudinal gradients. However, palaeoclimatic information based on biogenic low-Mg calcite δ18O for the Kimmeridgian is still limited. Here, shell materials (n?=?81) precipitated by brachiopods, oysters and Trichites bivalves from the Lower Saxony Basin, Northern Germany are evaluated for their potential to act as archive for marine sea-surface temperatures. Furthermore, the associated clay mineral assemblages based on bulk materials are used to infer hinterland weathering patterns and overall climatic conditions simultaneously. The established sea-surface temperature curve reveals an overall slightly warming trend through the Kimmeridgian. Weak seasonality (~4?°C) in sea-surface temperatures is documented by oxygen isotope variations measured along the growth lines of a large Trichites shell. Distinctly higher δ18O values observed in the Lower Kimmeridgian (late Baylei Chron) are interpreted to be related to the short-term influx of cooler boreal water masses. Judging from the corresponding smectite-dominated interval, however, the positive oxygen isotope anomaly may also be partly explained by a relatively drier climate causing enhanced δ18Oseawater values due to intensified evaporation. The kaolinite/(illite?+?chlorite) ratio points to a slightly long-term decrease in humidity through the Kimmeridgian on the landmasses surrounding the LSB. The short-term fluctuations in humid/arid conditions correlate significantly with sea-level changes, with humid climates accompanying high sea-levels and arid climates accompanying low sea-levels. Results from this study provide new insights into Late Jurassic climatic dynamics and help to establish a reliable Subboreal Late Jurassic sea-surface temperature curve. ................
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