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GEOCHEMISTRY ARTICLES – April 2020?Analytical ChemistryBorisova, O.V., Galstyan, A.G., Olenin, A.Y., Lisichkin, G.V., Zverev, V.V., 2020. Differential diagnostics of bacteria using the surface-enhanced Raman spectra. Microbiology 89, 192-196.Nardecchia, A., Fabre, C., Cauzid, J., Pelascini, F., Motto-Ros, V., Duponchel, L., 2020. Detection of minor compounds in complex mineral samples from millions of spectra: A new data analysis strategy in LIBS imaging. Analytica Chimica Acta 1114, 66-73.Extraction Methods/Sample PreparationAbdel-Rehim, M., Pedersen-Bjergaard, S., Abdel-Rehim, A., Lucena, R., Moein, M.M., Cárdenas, S., Miró, M., 2020. Microextraction approaches for bioanalytical applications: An overview. Journal of Chromatography A 1616, 460790.Auderset, A., Schmitt, M., Martínez-García, A., 2020. Simultaneous extraction and chromatographic separation of n-alkanes and alkenones from glycerol dialkyl glycerol tetraethers via selective Accelerated Solvent Extraction. Organic Geochemistry 143, 103979.Chasib, K.F., 2020. An investigation on the feasibility of using mixed reversible ionic liquids for extraction of kerogen from oil shale. Egyptian Journal of Petroleum 29, 53-57.Goh, S.X.L., Chong, B.H.D., Lee, H.K., 2020. Fully automated water sampling—surfactant-enhanced membrane bag liquid-phase microextraction—ultrahigh performance liquid chromatography–mass spectrometry. Analytical Chemistry 92, 5362-5369.Jalili, V., Barkhordari, A., Ghiasvand, A., 2020. Bioanalytical applications of microextraction techniques: A review of reviews. Chromatographia 83, 567-577.Jang, Y., Bang, J., Seon, Y.-S., You, D.-W., Oh, J.-S., Jung, K.-W., 2020. Carbon nanotube sponges as an enrichment material for aromatic volatile organic compounds. Journal of Chromatography A 1617, 460840.Li, W., Wu, J., Huang, X., 2020. Facile fabrication of functional groups-rich sorbent for the efficient enrichment of aromatic N- and S-containing compounds in environmental waters. Analytica Chimica Acta 1113, 36-42.Rach, O., Hadeen, X., Sachse, D., 2020. An automated solid phase extraction procedure for lipid biomarker purification and stable isotope analysis. Organic Geochemistry 142, 103995.Serra-Mora, P., Herráez-Hernández, R., Campíns-Falcó, P., 2020. Bimodal copper oxide nanoparticles doped phase for the extraction of highly polar compounds by in-tube solid-phase microextraction coupled on-line to nano-liquid chromatography. Journal of Chromatography A 1617, 460819.Tan, S., Helling, M.R., Basile, F., Li-Oakey, K.D., 2020. Systematic study of ionic liquids based coal extraction: Selectivity in extract molecular weights and targeted functional groups. Energy & Fuels 34, 4554-4564.Titaley, I.A., Eriksson, U., Larsson, M., 2020. Rapid extraction method of polycyclic aromatic compounds in soil using basic silica selective pressurized liquid extraction. Journal of Chromatography A 1618, 460896.Xie, Q., Sun, D., Xia, M., Jia, L., Lu, H., Shi, H., Hou, B., Li, D., 2020. Phase transfer catalyst-assisted reversed-phase dispersive liquid–liquid microextraction for the rapid determination of organic acids in Fischer-Tropsch oil products. Fuel 275, 117882.Xu, S., Li, H., Wu, H., Xiao, L., Dong, P., Feng, S., Fan, J., 2020. A facile cooling-assisted solid-phase microextraction device for solvent-free sampling of polycyclic aromatic hydrocarbons from soil based on matrix solid-phase dispersion technique. Analytica Chimica Acta 1115, 7-15.Gas Chromatography/GC×GC/GC-MSAmmar Khodja, F., Sassiat, P., Hanafi, M., Thiebaut, D., Vial, J., 2020. A promising "metastable" liquid crystal stationary phase for gas chromatography. Journal of Chromatography A 1616, 460786.Berrier, K.L., Freye, C.E., Billingsley, M.C., Synovec, R.E., 2020. Predictive modeling of aerospace fuel properties using comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry and partial least squares analysis. Energy & Fuels 34, 4084-4094.Delmonte, P., Belaunzaran, X., Ridge, C.D., Aldai, N., Kramer, J.K.G., 2020. Separation and characterization of products from acidic methanolysis of plasmalogenic lipids by two-dimensional gas chromatography with online reduction. Journal of Chromatography A 1619, 460955.Ferreira, V.H.C., Hantao, L.W., Poppi, R.J., 2020. Consumable-free comprehensive three-dimensional gas chromatography and PARAFAC for determination of allergens in perfumes. Chromatographia 83, 581-592.Guzman, M., Szopa, C., Freissinet, C., Buch, A., Stalport, F., Kaplan, D., Raulin, F., 2020. Testing the capabilities of the Mars Organic Molecule Analyser (MOMA) chromatographic columns for the separation of organic compounds on Mars. Planetary and Space Science 186, 104903.Han, Y., Yin, F., John, G.F., Clement, T.P., 2020. Understanding the relative performance of SCAN, SIM, PMRM and MRM methods for quantifying polycyclic aromatic hydrocarbons in crude oil samples. Rapid Communications in Mass Spectrometry 34, e8765.Kates, L.N., Richards, P.I., Sandau, C.D., 2020. The application of comprehensive two-dimensional gas chromatography to the analysis of wildfire debris for ignitable liquid residue. Forensic Science International 310, 110256.Khodja, F.A., Sassiat, P., Hanafi, M., Thiebaut, D., Vial, J., 2020. A promising "metastable" liquid crystal stationary phase for gas chromatography. Journal of Chromatography A 1616, 460786.Li, M., Zhu, R., Song, X., Wang, Z., Weng, H., Liang, J., 2020. A sensitive method for the quantification of short-chain fatty acids by benzyl chloroformate derivatization combined with GC-MS. Analyst 145, 2692-2700.Li, S., Hu, Y., Liu, W., Chen, Y., Wang, F., Lu, X., Zheng, W., 2020. Untargeted volatile metabolomics using comprehensive two-dimensional gas chromatography-mass spectrometry – A solution for orange juice authentication. Talanta 217, 121038.Li, W., Zhu, Y., Li, S., Lu, Y., Wang, J., Zhu, K., Chen, J., Zheng, Y., Zheng, Z., 2020. Catalytic fast pyrolysis of cellulose over Ce0.8Zr0.2-xAlxO2 catalysts to produce aromatic hydrocarbons: Analytical Py-GC?×?GC/MS. Fuel Processing Technology 205, 106438.Marcillo, A., Wei?, B.M., Widdig, A., Birkemeyer, C., 2020. Challenges of fast sampling of volatiles for thermal desorption gas chromatography - mass spectrometry. Journal of Chromatography A 1617, 460822.Nagornov, K.O., Zennegg, M., Kozhinov, A.N., Tsybin, Y.O., Bleiner, D., 2020. Trace-level persistent organic pollutant analysis with gas-chromatography Orbitrap mass spectrometry—enhanced performance by complementary acquisition and processing of time-domain data. Journal of the American Society for Mass Spectrometry 31, 257-266.Nyiri, Z., V?r?s-Palya, D., Novák, M., Eke, Z., 2020. Coupling of large volume injection with flow modulated two-dimensional gas chromatography. Talanta 216, 120984.Imaging: AFMAbarghani, A., Gentzis, T., Liu, B., Hohlbauch, S., Griffin, D., Bubach, B., Shokouhimehr, M., Ostadhassan, M., 2020. Bacterial vs. thermal degradation of algal matter: Analysis from a physicochemical perspective. International Journal of Coal Geology 223, 103465.Liu, Z., Cao, L., Zhou, T., Dong, Z., 2020. Multiscale investigation of moisture-induced structural evolution in asphalt–aggregate interfaces and analysis of the relevant chemical relationship using atomic force microscopy and molecular dynamics. Energy & Fuels 34, 4006-4016.Tazikeh, S., Sayyad Amin, J., Zendehboudi, S., Dejam, M., Chatzis, I., 2020. Bi-fractal and bi-Gaussian theories to evaluate impact of polythiophene-coated Fe3O4 nanoparticles on asphaltene precipitation and surface topography. Fuel 272, 117535.Yesufu-Rufai, S., Rücker, M., Berg, S., Lowe, S.F., Marcelis, F., Georgiadis, A., Luckham, P., 2020. Assessing the wetting state of minerals in complex sandstone rock in-situ by Atomic Force Microscopy (AFM). Fuel 273, 117807.Imaging: SEM, TEM, HIMAdeyilola, A., Nordeng, S., Onwumelu, C., Nwachukwu, F., Gentzis, T., 2020. Geochemical, petrographic and petrophysical characterization of the Lower Bakken Shale, Divide County, North Dakota. International Journal of Coal Geology 224, 103477.Albini, M., Ridolfi, S., Giuliani, C., Pascucci, M., Staccioli, M.P., Riccucci, C., 2020. Multi-spectroscopic approach for the non-invasive characterization of paintings on metal surfaces. Frontiers in Chemistry 8, 289. doi: 210.3389/fchem.2020.00289.Chen, X., Qu, X., Xu, S., Wang, W., Li, S., He, H., Liu, Y., 2020. Dissolution pores in shale and their influence on reservoir quality in Damintun Depression, Bohai Bay Basin, East China: Insights from SEM images, N2 adsorption and fluid-rock interaction experiments. Marine and Petroleum Geology 117, 104394.Du, Y., Fu, C., Pan, Z., Sang, S., Wang, W., Liu, S., Zhao, Y., Zhang, J., 2020. Geochemistry effects of supercritical CO2 and H2O on the mesopore and macropore structures of high-rank coal from the Qinshui Basin, China. International Journal of Coal Geology 223, 103467.Gr?dinaru, M., Laz?r, I., Ducea, M.N., Petrescu, L., 2020. Microaerophilic Fe-oxidizing micro-organisms in Middle Jurassic ferruginous stromatolites and the paleoenvironmental context of their formation (Southern Carpathians, Romania). Geobiology 18, 366-393.Gu, Y., Ding, W., Tian, Q., Xu, S., Zhang, W., Zhang, B., Jiao, B., 2020. Developmental characteristics and dominant factors of natural fractures in lower Silurian marine organic-rich shale reservoirs: A case study of the Longmaxi formation in the Fenggang block, southern China. Journal of Petroleum Science and Engineering 192, 107277.He, K., Pan, Y., 2020. Magnetofossil abundance and diversity as paleoenvironmental proxies: A case study from southwest Iberian margin sediments. Geophysical Research Letters 47, e2020GL087165.Joy, K.H., Tartèse, R., Messenger, S., Zolensky, M.E., Marrocchi, Y., Frank, D.R., Kring, D.A., 2020. The isotopic composition of volatiles in the unique Bench Crater carbonaceous chondrite impactor found in the Apollo 12 regolith. Earth and Planetary Science Letters 540, 116265.Kovalchuk, N., Hadjistassou, C., 2020. Fathoming the mechanics of shale gas production at the microscale. Journal of Natural Gas Science and Engineering 78, 103283.Lin, M., Grandinetti, G., Hartnell, L.M., Bliss, D., Subramaniam, S., Rikihisa, Y., 2020. Host membrane lipids are trafficked to membranes of intravacuolar bacterium Ehrlichia chaffeensis. Proceedings of the National Academy of Sciences 117, 8032-8043.Liu, L.-L., Hsieh, C.-Y., Kuo, M.-Y., Chen, C., Shau, Y.-H., Lui, H.-K., Yuan, C.-S., Chen, C.-T.A., 2020. Evidence for fossil fuel PM1 accumulation in marine biota. Environmental Science & Technology 54, 4068-4078.Moore, K.A., Altus, S., Tay, J.W., Meehl, J.B., Johnson, E.B., Bortz, D.M., Cameron, J.C., 2020. Mechanical regulation of photosynthesis in cyanobacteria. Nature Microbiology 5, 757-767.O'Keefe, J.M.K., Pound, M.J., Riding, J.B., Vane, C.H., 2020. Cellular preservation and maceral development in lignite and wood from the Brassington Formation (Miocene), Derbyshire, UK. International Journal of Coal Geology 222, 103452.Sharma, A., Singh, M.R., 2020. Multi-analytical investigation of the composition and binders used in the earthen support layer of fifth–fourteenth century CE painted fragments from Bezeklik, China. Studies in Conservation 65, 221-237.?oltys, K., Plan?, M., Biocca, P., Vianello, V., Bu?ková, M., Pu?kárová, A., Sclocchi, M.C., Colaizzi, P., Bicchieri, M., Pangallo, D., Pinzari, F., 2020. Lead soaps formation and biodiversity in a XVIII Century wax seal coloured with minium. Environmental Microbiology 22, 1517-1534.Sun, Z., Ni, Y., Wang, Y., Wei, Z., Wu, B., Li, J., Fan, W., Wang, G., Li, Y., 2019. Experimental investigation of the effects of different types of fracturing fluids on the pore structure characteristics of shale reservoir rocks. Energy Exploration & Exploitation 38, 682-702.Vranjes-Wessely, S., Misch, D., Issa, I., Kiener, D., Fink, R., Seemann, T., Liu, B., Rantitsch, G., Sachsenhofer, R.F., 2020. Nanoscale pore structure of Carboniferous coals from the Ukrainian Donets Basin: A combined HRTEM and gas sorption study. International Journal of Coal Geology 224, 103484.Wang, Y.S., Liu, L., Fu, Q., Sun, J., An, Z.Y., Ding, R., Li, Y., Zhao, X.D., 2020. Effect of Bacillus subtilis on corrosion behavior of 10MnNiCrCu steel in marine environment. Scientific Reports 10, 5744.Wu, Z., He, S., Han, Y., Zhai, G., He, X., Zhou, Z., 2020. Effect of organic matter type and maturity on organic matter pore formation of transitional facies shales: A case study on Upper Permian Longtan and Dalong shales in Middle Yangtze Region, China. Journal of Earth Science 31, 368-384.Xiao, S., Cui, H., Kang, J., McFadden, K.A., Kaufman, A.J., Kitajima, K., Fournelle, J.H., Schwid, M., Nolan, M., Baele, J.-M., Valley, J.W., 2020. Using SIMS to decode noisy stratigraphic δ13C variations in Ediacaran carbonates. Precambrian Research 343, 105686.Zhang, P., Lu, S., Li, J., Chang, X., Li, J., Li, W., Chen, G., Wang, S., Feng, W., 2019. Broad ion beam-scanning electron microscopy pore microstructure and multifractal characterization of shale oil reservoir: A case sample from Dongying Sag, Bohai Bay Basin, China. Energy Exploration & Exploitation 38, 613-628.Ziemiański, P.P., Derkowski, A., Szczurowski, J., Kozie?, M., 2020. The structural versus textural control on the methane sorption capacity of clay minerals. International Journal of Coal Geology 224, 103483.Imaging: Xray CTChen, Y., Jha, N.K., Al-Bayati, D., Lebedev, M., Sarmadivaleh, M., Iglauer, S., Saeedi, A., Xie, Q., 2020. Geochemical controls on wettability alteration at pore-scale during low salinity water flooding in sandstone using X-ray micro computed tomography. Fuel 271, 117675.Lucas, M., Pihlap, E., Steffens, M., Vetterlein, D., K?gel-Knabner, I., 2020. Combination of imaging infrared spectroscopy and X-ray computed microtomography for the investigation of bio- and physicochemical processes in structured soils. Frontiers in Environmental Science 8, 42. doi: 10.3389/fenvs.2020.00042.Shi, R., Liu, J., Wang, X., Elsworth, D., Liu, Z., Wei, M., Liu, X., Wang, Z., 2020. Experimental observations of heterogeneous strains inside a dual porosity sample under the influence of gas-sorption: A case study of fractured coal. International Journal of Coal Geology 223, 103450.Wang, J., Belhaj, H., Bera, A., 2020. Investigations on geological aspects of capillary transition zones of carbonate reservoirs by applied imaging techniques. International Journal of Oil, Gas and Coal Technology 24, 85-101.Liquid Chromatography/LC-MS/SFCAbba, S.I., Usman, A.G., I?ik, S., 2020. Simulation for response surface in the HPLC optimization method development using artificial intelligence models: A data-driven approach. Chemometrics and Intelligent Laboratory Systems 201, 104007.Bosch-Orea, C., Sanchís, J., Barceló, D., Farré, M., 2020. Ultra-trace determination of domoic acid in the Ebro Delta estuary by SPE-HILIC-HRMS. Analytical Methods 12, 1966-1974.Ferreira, P.S., Madeira, N.C.L., Folli, G.S., Rom?o, W., Filgueiras, P.R., Kuster, R.M., 2020. SAP fractions from light, medium and heavy oils: Correlation between chemical profile and stationary phases. Fuel 274, 117866.Garrigues, J.-C., Cournac, M., Oswald, M., Ritter, N., Blanzat, M., Cassel, S., 2020. Analysis of complex mixtures of polyglycerol fatty esters using liquid chromatography and high-resolution mass spectrometry: retention, structural and relative composition study. Journal of Chromatography A 1616, 460792.Goh, S.X.L., Chong, B.H.D., Lee, H.K., 2020. Fully automated water sampling—surfactant-enhanced membrane bag liquid-phase microextraction—ultrahigh performance liquid chromatography–mass spectrometry. Analytical Chemistry 92, 5362-5369.Harps, L.C., Schipperges, S., Bredendiek, F., Wuest, B., Borowiak, A., Parr, M.K., 2020. Two dimensional chromatography mass spectrometry: Quantitation of chiral shifts in metabolism of propranolol in bioanalysis. Journal of Chromatography A 1617, 460828.Kotapati, H.K., Bates, P.D., 2020. Normal phase HPLC method for combined separation of both polar and neutral lipid classes with application to lipid metabolic flux. Journal of Chromatography B 1145, 122099.Kruve, A., 2020. Strategies for drawing quantitative conclusions from nontargeted liquid chromatography–high-resolution mass spectrometry analysis. Analytical Chemistry 92, 4691-4699.Pan, H., Li, A., Cui, Z., Ding, D., Qu, K., Zheng, Y., Lu, L., Jiang, T., Jiang, T., 2020. A comparative study of phytoplankton community structure and biomass determined by HPLC-CHEMTAX and microscopic methods during summer and autumn in the central Bohai Sea, China. Marine Pollution Bulletin 155, 111172.Pérez-Cova, M., Tauler, R., Jaumot, J., 2020. Chemometrics in comprehensive two-dimensional liquid chromatography: A study of the data structure and its multilinear behavior. Chemometrics and Intelligent Laboratory Systems 201, 104009.Pickens, C.J., Haidar Ahmad, I.A., Makarov, A.A., Bennett, R., Mann, B.F., Regalado, E.L., 2020. Comprehensive online multicolumn two-dimensional liquid chromatography-diode array detection-mass spectrometry workflow as a framework for chromatographic screening and analysis of new drug substances. Analytical and Bioanalytical Chemistry 412, 2655-2663.?esták, J., Planeta, J., Kahle, V., 2020. Compact optical detector utilizing light emitting diodes, 50?nL L-shaped silica capillary cell and CCD spectrometer for simultaneous multi-wavelength monitoring of absorbance and fluorescence in microcolumn liquid chromatography. Analytica Chimica Acta 1112, 80-91.Mass Spectroscopy/ICR-FTMS/OrbitrapCai, D., Wang, X., Chen, J., Li, X., 2020. Molecular characterization of organosulfates in highly polluted atmosphere using ultra-high-resolution mass spectrometry. Journal of Geophysical Research: Atmospheres 125, e2019JD032253.Castilla, C., Rüger, C.P., Marcotte, S., Lavanant, H., Afonso, C., 2020. Direct inlet probe atmospheric pressure photo and chemical ionization coupled to ultrahigh resolution mass spectrometry for the description of lignocellulosic biomass. Journal of the American Society for Mass Spectrometry 31, 822-831.Criscuolo, A., Zeller, M., Fedorova, M., 2020. Evaluation of lipid in-source fragmentation on different Orbitrap-based mass spectrometers. Journal of the American Society for Mass Spectrometry 31, 463-466.Domínguez, I., Arrebola, F.J., Martínez Vidal, J.L., Garrido Frenich, A., 2020. Assessment of wastewater pollution by gas chromatography and high resolution Orbitrap mass spectrometry. Journal of Chromatography A 1619, 460964.Feng, L., An, Y., Xu, J., Li, X., Jiang, B., Liao, Y., 2020. Biochemical evolution of dissolved organic matter during snow metamorphism across the ablation season for a glacier on the central Tibetan Plateau. Scientific Reports 10, 6123.Ferreira, P.S., Madeira, N.C.L., Folli, G.S., Rom?o, W., Filgueiras, P.R., Kuster, R.M., 2020. SAP fractions from light, medium and heavy oils: Correlation between chemical profile and stationary phases. Fuel 274, 117866.Folberth, J., Begemann, K., J?hren, O., Schwaninger, M., Othman, A., 2020. MS2 and LC libraries for untargeted metabolomics: Enhancing method development and identification confidence. Journal of Chromatography B 1145, 122105.Jiménez-González, M.A., Almendros, G., Waggoner, D.C., ?lvarez, A.M., Hatcher, P.G., 2020. Assessment of the molecular composition of humic acid as an indicator of soil carbon levels by ultra-high-resolution mass spectrometric analysis. Organic Geochemistry 143, 104012.Lee, C.P., Riva, M., Wang, D., Tomaz, S., Li, D., Perrier, S., Slowik, J.G., Bourgain, F., Schmale, J., Prevot, A.S.H., Baltensperger, U., George, C., El Haddad, I., 2020. Online aerosol chemical characterization by extractive electrospray ionization–ultrahigh-resolution mass spectrometry (EESI-Orbitrap). Environmental Science & Technology 54, 3871-3880.Nagornov, K.O., Zennegg, M., Kozhinov, A.N., Tsybin, Y.O., Bleiner, D., 2020. Trace-level persistent organic pollutant analysis with gas-chromatography orbitrap mass spectrometry—enhanced performance by complementary acquisition and processing of time-domain data. Journal of the American Society for Mass Spectrometry 31, 257-266.Perry, W.J., Patterson, N.H., Prentice, B.M., Neumann, E.K., Caprioli, R.M., Spraggins, J.M., 2020. Uncovering matrix effects on lipid analyses in MALDI imaging mass spectrometry experiments. Journal of Mass Spectrometry 55, e4491.Ye, H., Liu, B., Wang, Q., How, Z.T., Zhan, Y., Chelme-Ayala, P., Guo, S., El-Din, M.G., Chen, C., 2020. Comprehensive chemical analysis and characterization of heavy oil electric desalting wastewaters in petroleum refineries. Science of The Total Environment 724, 138117.Mass Spectroscopy/OtherAlves, G., Yu, Y.-K., 2020. Robust accurate identification and biomass estimates of microorganisms via tandem mass spectrometry. Journal of the American Society for Mass Spectrometry 31, 85-102.Bai, H., Khodjaniyazova, S., Garrard, K.P., Muddiman, D.C., 2020. Three-dimensional imaging with infrared matrix-assisted laser desorption electrospray ionization mass spectrometry. Journal of the American Society for Mass Spectrometry 31, 292-297.Bowman, A.P., Bogie, J.F.J., Hendriks, J.J.A., Haidar, M., Belov, M., Heeren, R.M.A., Ellis, S.R., 2020. Evaluation of lipid coverage and high spatial resolution MALDI-imaging capabilities of oversampling combined with laser post-ionisation. Analytical and Bioanalytical Chemistry 412, 2277-2289.Feng, B., Shi, H., Xu, F., Hu, F., He, J., Yang, H., Ding, C., Chen, W., Yu, S., 2020. FTIR-assisted MALDI-TOF MS for the identification and typing of bacteria. Analytica Chimica Acta 1111, 75-82.Heiles, S., Kompauer, M., Müller, M.A., Spengler, B., 2020. Atmospheric-pressure MALDI mass spectrometry imaging at 213 nm laser wavelength. Journal of the American Society for Mass Spectrometry 31, 326-335.Kaufmann, A., Butcher, P., Maden, K., Walker, S., Widmer, M., 2020. Does the ion mobility resolving power as provided by commercially available ion mobility quadrupole time-of-flight mass spectrometry instruments permit the unambiguous identification of small molecules in complex matrices? Analytica Chimica Acta 1107, 113-126.Perry, W.J., Patterson, N.H., Prentice, B.M., Neumann, E.K., Caprioli, R.M., Spraggins, J.M., 2020. Uncovering matrix effects on lipid analyses in MALDI imaging mass spectrometry experiments. Journal of Mass Spectrometry 55, e4491.Ren, Z., Guo, M., Cheng, Y., Sun, W., Li, G., Dong, M., Li, Y., Xi, Z., Pei, X., Niu, H., Tan, G., Zhou, Z., Huang, Z., 2020. Design of a compact time-of-flight mass spectrometer for space application. Journal of the American Society for Mass Spectrometry 31, 434-440.Smets, T., Waelkens, E., De Moor, B., 2020. Prioritization of m/z-values in mass spectrometry imaging profiles obtained using uniform manifold approximation and projection for dimensionality reduction. Analytical Chemistry 92, 5240-5248.Tega, D.U., Nascimento, H., Jara, J.L., Santos, J.M., Eberlin, M.N., 2020. A rapid and versatile method to determine methanol in biofuels and gasoline by ambient mass spectrometry using a V-EASI source. Energy & Fuels 34, 4595-4602.Verbeeck, N., Caprioli, R.M., Van de Plas, R., 2020. Unsupervised machine learning for exploratory data analysis in imaging mass spectrometry. Mass Spectrometry Reviews 39, 245-291.Xiao, S., Cui, H., Kang, J., McFadden, K.A., Kaufman, A.J., Kitajima, K., Fournelle, J.H., Schwid, M., Nolan, M., Baele, J.-M., Valley, J.W., 2020. Using SIMS to decode noisy stratigraphic δ13C variations in Ediacaran carbonates. Precambrian Research 343, 105686.Yu, Q., Xu, S., Shi, W., Tian, Y., Wang, X., 2020. Mass spectrometry coupled with vacuum thermal desorption for enhanced volatile organic sample analysis. Analytical Methods 12, 1852-1857.Metabolomics/LipidomicsBagley, M.C., Ekel?f, M., Muddiman, D.C., 2020. Determination of optimal electrospray parameters for lipidomics in infrared-matrix-assisted laser desorption electrospray ionization mass spectrometry imaging. Journal of the American Society for Mass Spectrometry 31, 319-325.Criado-Navarro, I., Mena-Bravo, A., Calderón-Santiago, M., Priego-Capote, F., 2020. Profiling analysis of phospholipid fatty acids in serum as a complement to the comprehensive fatty acids method. Journal of Chromatography A 1619, 460965.Criscuolo, A., Zeller, M., Fedorova, M., 2020. Evaluation of lipid in-source fragmentation on different Orbitrap-based mass spectrometers. Journal of the American Society for Mass Spectrometry 31, 463-466.Damiani, C., Gaglio, D., Sacco, E., Alberghina, L., Vanoni, M., 2020. Systems metabolomics: from metabolomic snapshots to design principles. Current Opinion in Biotechnology 63, 190-199.Delmonte, P., Belaunzaran, X., Ridge, C.D., Aldai, N., Kramer, J.K.G., 2020. Separation and characterization of products from acidic methanolysis of plasmalogenic lipids by two-dimensional gas chromatography with online reduction. Journal of Chromatography A 1619, 460955.Folberth, J., Begemann, K., J?hren, O., Schwaninger, M., Othman, A., 2020. MS2 and LC libraries for untargeted metabolomics: Enhancing method development and identification confidence. Journal of Chromatography B 1145, 122105.Garate, J., Lage, S., Martín-Saiz, L., Perez-Valle, A., Ochoa, B., Boyano, M.D., Fernández, R., Fernández, J.A., 2020. Influence of lipid fragmentation in the data analysis of imaging mass spectrometry experiments. Journal of the American Society for Mass Spectrometry 31, 517-526.Heuillet, M., Millard, P., Cissé, M.Y., Linares, L.K., Létisse, F., Manié, S., Le Cam, L., Portais, J.-C., Bellvert, F., 2020. Simultaneous measurement of metabolite concentration and isotope incorporation by mass spectrometry. Analytical Chemistry 92, 5890-5896.Kotapati, H.K., Bates, P.D., 2020. Normal phase HPLC method for combined separation of both polar and neutral lipid classes with application to lipid metabolic flux. Journal of Chromatography B 1145, 122099.Kruve, A., 2020. Strategies for drawing quantitative conclusions from nontargeted liquid chromatography–high-resolution mass spectrometry analysis. Analytical Chemistry 92, 4691-4699.Li, D., Liu, B., Zheng, H., Xiao, X., Li, Z., Luan, E., Li, W., Yang, Y., Wang, Y., Long, Q., Song, J., Zhang, G., 2020. XY-Meta: A high-efficiency search engine for large-scale metabolome annotation with accurate FDR estimation. Analytical Chemistry 92, 5701-5707.Li, S., Hu, Y., Liu, W., Chen, Y., Wang, F., Lu, X., Zheng, W., 2020. Untargeted volatile metabolomics using comprehensive two-dimensional gas chromatography-mass spectrometry – A solution for orange juice authentication. Talanta 217, 121038.Lv, W., Wang, L., Xuan, Q., Zhao, X., Liu, X., Shi, X., Xu, G., 2020. Pseudotargeted method based on parallel column two-dimensional liquid chromatography-mass spectrometry for broad coverage of metabolome and lipidome. Analytical Chemistry 92, 6043-6050.Mak, T.D., Goudarzi, M., Laiakis, E.C., Stein, S.E., 2020. Disparate metabolomics data reassembler: A novel algorithm for agglomerating incongruent LC-MS metabolomics datasets. Analytical Chemistry 92, 5231-5239.McLean, C., Kujawinski, E.B., 2020. AutoTuner: High fidelity and robust parameter selection for metabolomics data processing. Analytical Chemistry 92, 5724-5732.Murphy, R.C., 2020. Lipid mass spectrometry: A path traveled for 50 years. 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Microbial enhanced oil recovery potential of surfactin-producing Bacillus subtilis AB2.0. Fuel 272, 117730.Behera, U.S., Sangwai, J.S., 2020. Synergistic effect of brine system containing mixed monovalent (NaCl, KCl) and divalent (MgCl2, MgSO4) salts on the interfacial tension of pure hydrocarbon-brine system relevant for low salinity water flooding. Energy & Fuels 34, 4201-4212.Chen, Y., Jha, N.K., Al-Bayati, D., Lebedev, M., Sarmadivaleh, M., Iglauer, S., Saeedi, A., Xie, Q., 2020. Geochemical controls on wettability alteration at pore-scale during low salinity water flooding in sandstone using X-ray micro computed tomography. Fuel 271, 117675.Fang, T., Zhang, Y., Yan, Y., Dai, C., Zhang, J., 2020. Molecular insight into the aggregation and dispersion behavior of modified nanoparticles. Journal of Petroleum Science and Engineering 191, 107193.Huang, H., Babadagli, T., Chen, X., Andy Li, H., 2020. Performance comparison of novel chemical agents in improving oil recovery from tight sands through spontaneous imbibition. Petroleum Science 17, 409-418.Jahanbani Veshareh, M., Ayatollahi, S., 2020. Microorganisms’ effect on the wettability of carbonate oil-wet surfaces: implications for MEOR, smart water injection and reservoir souring mitigation strategies. Journal of Petroleum Exploration and Production Technology 10, 1539-1550.Xie, Y., Khishvand, M., Piri, M., 2020. Impact of connate brine chemistry on in situ wettability and oil recovery: Pore-scale experimental investigation. Energy & Fuels 34, 4031-4045.Yan, L., Aslannejad, H., Hassanizadeh, S.M., Raoof, A., 2020. Impact of water salinity differential on a crude oil droplet constrained in a capillary: Pore-scale mechanisms. Fuel 274, 117798.Yesufu-Rufai, S., Rücker, M., Berg, S., Lowe, S.F., Marcelis, F., Georgiadis, A., Luckham, P., 2020. Assessing the wetting state of minerals in complex sandstone rock in-situ by Atomic Force Microscopy (AFM). Fuel 273, 117807.Zhang, Z., Liu, H., Wang, J., 2020. Energetics of interfacial interactions of hydrocarbon fluids with kerogen and calcite using molecular modeling. Energy & Fuels 34, 4251-4259.Heavy Oil ProductionAnsari, S., Sabbagh, R., Yusuf, Y., Nobes, D.S., 2020. The role of emulsions in steam-assisted-gravity-drainage (SAGD) oil-production process: A review. SPE-199879-PA 25, 969-989.Huang, J., Babadagli, T., 2020. Efficiency improvement of heavy-oil recovery by steam-assisted gravity drainage injection using new generation chemicals. Energy & Fuels 34, 4433-4447.Novel MaterialsLiu, M., Li, W., Ruan, S., Fei, Y., 2020. N-doped hierarchical mesoporous carbon from mesophase pitch and polypyrrole for supercapacitors. Energy & Fuels 34, 5044-5051.Yang, L., Yang, Y., Wang, S., Guan, X., Guan, X., Wang, G., 2020. Multi-heteroatom-doped carbon materials for solid-state hybrid supercapacitors with a superhigh cycling performance. Energy & Fuels 34, 5032-5043.Recent SedimentsAkam, S.A., Coffin, R.B., Abdulla, H.A.N., Lyons, T.W., 2020. Dissolved inorganic carbon pump in methane-charged shallow marine sediments: State of the art and new model perspectives. Frontiers in Marine Science 7, 206. doi: 210.3389/fmars.2020.00206.Bardhan, P., Naqvi, S.W.A., 2020. Nitrogen and carbon cycling over the western continental shelf of India during seasonal anoxia: A stable isotope approach. Journal of Marine Systems 207, 103144.Bennett, W.W., Canfield, D.E., 2020. Redox-sensitive trace metals as paleoredox proxies: A review and analysis of data from modern sediments. Earth-Science Reviews 204, 103175.Bosch-Orea, C., Sanchís, J., Barceló, D., Farré, M., 2020. Ultra-trace determination of domoic acid in the Ebro Delta estuary by SPE-HILIC-HRMS. Analytical Methods 12, 1966-1974.de Bar, M.W., Weiss, G., Yildiz, C., Rampen, S.W., Lattaud, J., Bale, N.J., Mienis, F., Brummer, G.-J.A., Schulz, H., Rush, D., Kim, J.-H., Donner, B., Knies, J., Lückge, A., Stuut, J.-B.W., Sinninghe Damsté, J.S., Schouten, S., 2020. Global temperature calibration of the Long chain Diol Index in marine surface sediments. Organic Geochemistry 142, 103983.Fernandes, S., Mazumdar, A., Peketi, A., Anand, S.S., Rengarajan, R., Jose, A., Manaskanya, A., Carvalho, M.A., Shetty, D., 2020. Sulfidization processes in seasonally hypoxic shelf sediments: A study off the West coast of India. Marine and Petroleum Geology 117, 104353.Hirave, P., Wiesenberg, G.L.B., Birkholz, A., Alewell, C., 2020. Understanding the effects of early degradation on isotopic tracers: implications for sediment source attribution using compound-specific isotope analysis (CSIA). Biogeosciences 17, 2169-2180.Jiménez-Arias, J.L., Morris, E., Rubio-de-Inglés, M.J., Peralta, G., García-Robledo, E., Corzo, A., Papaspyrou, S., 2020. Tidal elevation is the key factor modulating burial rates and composition of organic matter in a coastal wetland with multiple habitats. Science of The Total Environment 724, 138205.Kurian, S., Kessarkar, P.M., Purnachandra Rao, V., Reshma, K., Sarkar, A., Pattan, J.N., Naqvi, S.W.A., 2020. Controls on organic matter distribution in oxygen minimum zone sediments from the continental slope off western India. Journal of Marine Systems 207, 103118.Pondell, C.R., Canuel, E.A., 2020. Sterol, fatty acid, and lignin biomarkers identify the response of organic matter accumulation in Englebright Lake, California (USA) to climate and human impacts. Organic Geochemistry 142, 103992.Sun, C.-H., Zhu, M.-X., Ma, W.-W., Sun, Z.-L., Zhang, X.-R., Ding, K.-Y., Liu, S.-H., 2020. Examining bulk and iron-associated organic carbon through depth in margin sea sediments (China) under contrasting depositional settings: Chemical and NEXAFS spectral characterization. Journal of Marine Systems 207, 103344.Sun, X., Fan, D., Liu, M., Liao, H., Tian, Y., 2020. The fate of organic carbon burial in the river-dominated East China Sea: Evidence from sediment geochemical records of the last 70?years. Organic Geochemistry 143, 103999.Troina, G.C., Dehairs, F., Botta, S., Tullio, J.C.D., Elskens, M., Secchi, E.R., 2020. Zooplankton-based δ13C and δ15N isoscapes from the outer continental shelf and slope in the subtropical western South Atlantic. Deep Sea Research Part I: Oceanographic Research Papers 159, 103235.Vuillemin, A., Friese, A., Wirth, R., Schuessler, J.A., Schleicher, A.M., Kemnitz, H., Lücke, A., Bauer, K.W., Nomosatryo, S., von Blanckenburg, F., Simister, R., Ordo?ez, L.G., Ariztegui, D., Henny, C., Russell, J.M., Bijaksana, S., Vogel, H., Crowe, S.A., Kallmeyer, J., the Towuti Drilling Project Science team, 2020. Vivianite formation in ferruginous sediments from Lake Towuti, Indonesia. Biogeosciences 17, 1955-1973.Xiao, W., Wang, Y., Liu, Y., Zhang, X., Shi, L., Xu, Y., 2020. Predominance of hexamethylated 6-methyl branched glycerol dialkyl glycerol tetraethers in the Mariana Trench: source and environmental implication. Biogeosciences 17, 2135-2148.Zhang, Y., Xiao, X., Liu, D., Wang, E., Liu, K., Ding, Y., Yao, P., Zhao, M., 2020. Spatial and seasonal variations of organic carbon distributions in typical intertidal sediments of China. Organic Geochemistry 142, 103993.Atmospheric GeochemistryCai, D., Wang, X., Chen, J., Li, X., 2020. Molecular characterization of organosulfates in highly polluted atmosphere using ultra-high-resolution mass spectrometry. Journal of Geophysical Research: Atmospheres 125, e2019JD032253.Gorchov Negron, A.M., Kort, E.A., Conley, S.A., Smith, M.L., 2020. Airborne assessment of methane emissions from offshore platforms in the U.S. Gulf of Mexico. Environmental Science & Technology 54, 5112-5120.Jang, Y., Bang, J., Seon, Y.-S., You, D.-W., Oh, J.-S., Jung, K.-W., 2020. Carbon nanotube sponges as an enrichment material for aromatic volatile organic compounds. Journal of Chromatography A 1617, 460840.Lee, C.P., Riva, M., Wang, D., Tomaz, S., Li, D., Perrier, S., Slowik, J.G., Bourgain, F., Schmale, J., Prevot, A.S.H., Baltensperger, U., George, C., El Haddad, I., 2020. Online aerosol chemical characterization by extractive electrospray ionization–ultrahigh-resolution mass spectrometry (EESI-Orbitrap). Environmental Science & Technology 54, 3871-3880.Liu, L.-L., Hsieh, C.-Y., Kuo, M.-Y., Chen, C., Shau, Y.-H., Lui, H.-K., Yuan, C.-S., Chen, C.-T.A., 2020. Evidence for fossil fuel PM1 accumulation in marine biota. Environmental Science & Technology 54, 4068-4078.Tripathi, N., Sahu, L.K., Singh, A., Yadav, R., Karati, K.K., 2020. High levels of isoprene in the marine boundary layer of the Arabian Sea during spring inter-monsoon: Role of phytoplankton blooms. ACS Earth and Space Chemistry 4, 583-590.Hydrosphere GeochemistryBepari, K.F., Shenoy, D.M., Chndrasekhara Rao, A.V., Kurian, S., Gauns, M.U., Naik, B.R., Naqvi, S.W.A., 2020. Dynamics of dimethylsulphide and associated compounds in the coastal waters of Goa, west coast of India. Journal of Marine Systems 207, 103228.De Haan, D.O., Jansen, K., Rynaski, A.D., Sueme, W.R.P., Torkelson, A.K., Czer, E.T., Kim, A.K., Rafla, M.A., De Haan, A.C., Tolbert, M.A., 2020. Brown carbon production by aqueous-phase interactions of glyoxal and SO2. Environmental Science & Technology 54, 4781-4789.Ding, L., Qi, Y., Shan, S., Ge, T., Luo, C., Wang, X., 2020. Radiocarbon in dissolved organic and inorganic carbon of the South China Sea. Journal of Geophysical Research: Oceans 125, e2020JC016073.Eckard, R.S., Bergamaschi, B.A., Pellerin, B., Spencer, R.G., Dyda, R., Hernes, P.J., 2020. Organic matter integration, overprinting, and the relative fraction of optically active organic carbon in a human-impacted watershed. Frontiers in Earth Science 8, 67. doi: 10.3389/feart.2020.00067.Feng, L., An, Y., Xu, J., Li, X., Jiang, B., Liao, Y., 2020. Biochemical evolution of dissolved organic matter during snow metamorphism across the ablation season for a glacier on the central Tibetan Plateau. Scientific Reports 10, 6123.Gao, C., Fernandez, V.I., Lee, K.S., Fenizia, S., Pohnert, G., Seymour, J.R., Raina, J.-B., Stocker, R., 2020. Single-cell bacterial transcription measurements reveal the importance of dimethylsulfoniopropionate (DMSP) hotspots in ocean sulfur cycling. Nature Communications 11, 1942.Gennadiev, A.N., Zhidkin, A.P., Koshovskii, T.S., 2020. Factors and trends in the formation of natural–technogenic associations of polycyclic aromatic hydrocarbons in the snow–soil system. Doklady Earth Sciences 490, 36-39.Heddam, S., Keshtegar, B., Kisi, O., 2020. Predicting total dissolved gas concentration on a daily scale using kriging interpolation, response surface method and artificial neural network: Case study of Columbia River Basin dams, USA. Natural Resources Research 29, 1801-1818.Herzog, S.D., Gentile, L., Olsson, U., Persson, P., Kritzberg, E.S., 2020. Characterization of iron and organic carbon colloids in boreal rivers and their fate at high salinity. Journal of Geophysical Research: Biogeosciences 125, e2019JG005517.Imtiazy, M.N., Paterson, A.M., Higgins, S.N., Yao, H., Couture, S., Hudson, J.J., 2020. Dissolved organic carbon in eastern Canadian lakes: Novel patterns and relationships with regional and global factors. Science of The Total Environment 726, 138400.Maerz, J., Six, K.D., Stemmler, I., Ahmerkamp, S., Ilyina, T., 2020. Microstructure and composition of marine aggregates as co-determinants for vertical particulate organic carbon transfer in the global ocean. Biogeosciences 17, 1765-1803.Russkikh, I.V., Strel’nikova, E.B., Serebrennikova, O.V., Voistinova, E.S., Kharanzhevskaya, Y.A., 2020. Identification of hydrocarbons in the waters of raised bogs in the southern taiga of Western Siberia. Geochemistry International 58, 447-455.Sanchís, J., Jaén-Gil, A., Gago-Ferrero, P., Munthali, E., Farré, M.J., 2020. Characterization of organic matter by HRMS in surface waters: Effects of chlorination on molecular fingerprints and correlation with DBP formation potential. Water Research 176, 115743.Torres, M.A., Kemeny, P.C., Lamb, M.P., Cole, T.L., Fischer, W.W., 2020. Long-term storage and age-biased export of fluvial organic carbon: Field evidence from West Iceland. Geochemistry, Geophysics, Geosystems 21, e2019GC008632.Whitby, H., Planquette, H., Cassar, N., Bucciarelli, E., Osburn, C.L., Janssen, D.J., Cullen, J.T., González, A.G., V?lker, C., Sarthou, G., 2020. A call for refining the role of humic-like substances in the oceanic iron cycle. Scientific Reports 10, 6144.Yuan, D., Wang, W., Liu, C., Xu, L., Fei, H., Wang, X., Shen, M., Wang, S., Wang, M., Zhu, G., 2020. Source, contribution and microbial N-cycle of N-compounds in China fresh snow. Environmental Research 183, 109146.Zito, P., Podgorski, D.C., Bartges, T., Guillemette, F., Roebuck, J.A., Spencer, R.G.M., Rodgers, R.P., Tarr, M.A., 2020. Sunlight-induced molecular progression of oil into oxidized oil soluble species, interfacial material, and dissolved organic matter. Energy & Fuels 34, 4721-4726.Soil GeochemistryBraun, M., Kappenberg, A., Sandhage-Hofmann, A., Lehndorff, E., 2020. Leachable soil black carbon after biochar application. Organic Geochemistry 143, 103996.Chu, H., Gao, G.-F., Ma, Y., Fan, K., Delgado-Baquerizo, M., 2020. Soil microbial biogeography in a changing world: Recent advances and future perspectives. mSystems 5, e00803-00819.Gennadiev, A.N., Zhidkin, A.P., Koshovskii, T.S., 2020. Factors and trends in the formation of natural–technogenic associations of polycyclic aromatic hydrocarbons in the snow–soil system. Doklady Earth Sciences 490, 36-39.Jiménez-González, M.A., Almendros, G., Waggoner, D.C., ?lvarez, A.M., Hatcher, P.G., 2020. Assessment of the molecular composition of humic acid as an indicator of soil carbon levels by ultra-high-resolution mass spectrometric analysis. Organic Geochemistry 143, 104012.Lin, Y., Campbell, A.N., Bhattacharyya, A., DiDonato, N., Thompson, A.M., Tfaily, M.M., Nico, P.S., Silver, W.L., Pett-Ridge, J., 2020. Differential effects of redox conditions on the decomposition of litter and soil organic matter. Biogeosciences Discussions 2020, 1-25.Lu, J., Zang, J., Meyers, P., Huang, X., Qiu, P., Yu, X., Yang, H., Xie, S., 2020. Surface soil n-alkane molecular and δD distributions along a precipitation transect in northeastern China. Organic Geochemistry 144, 104015.Lucas, M., Pihlap, E., Steffens, M., Vetterlein, D., K?gel-Knabner, I., 2020. Combination of imaging infrared spectroscopy and X-ray computed microtomography for the investigation of bio- and physicochemical processes in structured soils. Frontiers in Environmental Science 8, 42. doi: 10.3389/fenvs.2020.00042.Lv, J., Han, R., Luo, L., Zhang, X., Zhang, S., 2020. A novel strategy to evaluate the aromaticity degree of natural organic matter based on oxidization-induced chemiluminescence. Environmental Science & Technology 54, 4171-4179.Manucharova, N.A., Ksenofontova, N.A., Karimov, T.D., Vlasova, A.P., Zenova, G.M., Stepanov, A.L., 2020. Changes in the phylogenetic structure of the metabolically active prokaryotic soil complex induced by oil pollution. Microbiology 89, 219-230.Qin, X.-q., Yao, B., Jin, L., Zheng, X.-z., Ma, J., Benedetti, M.F., Li, Y., Ren, Z.-l., 2020. Characterizing soil dissolved organic matter in typical soils from China using fluorescence EEM–PARAFAC and UV–visible absorption. Aquatic Geochemistry 26, 71-88.Yoon, H.Y., Jeong, H.J., Cha, J.-Y., Choi, M., Jang, K.-S., Kim, W.-Y., Kim, M.G., Jeon, J.-R., 2020. Structural variation of humic-like substances and its impact on plant stimulation: Implication for structure-function relationship of soil organic matters. Science of The Total Environment 725, 138409.Remote Sensing-Hydrocarbon SeepageAsadzadeh, S., Souza Filho, C.R., 2020. Characterization of microseepage-induced diagenetic changes in the Upper-Red Formation, Qom region, Iran. Part II: A new insight using reflectance spectroscopic analysis. Marine and Petroleum Geology 117, 104387.Dupré, S., Loubrieu, B., Pierre, C., Scalabrin, C., Guérin, C., Ehrhold, A., Ogor, A., Gautier, E., Ruffine, L., Biville, R., Saout, J., Breton, C., Floodpage, J., Lescanne, M., 2020. The Aquitaine shelf edge (Bay of Biscay): A primary outlet for microbial methane release. Geophysical Research Letters 47, e2019GL084561.Girard, F., Sarrazin, J., Olu, K., 2020. Impacts of an eruption on cold-seep microbial and faunal dynamics at a mud volcano. Frontiers in Marine Science 7, 241. doi: 210.3389/fmars.2020.00241.Goffredi, S.K., Tilic, E., Mullin, S.W., Dawson, K.S., Keller, A., Lee, R.W., Wu, F., Levin, L.A., Rouse, G.W., Cordes, E.E., Orphan, V.J., 2020. Methanotrophic bacterial symbionts fuel dense populations of deep-sea feather duster worms (Sabellida, Annelida) and extend the spatial influence of methane seepage. Science Advances 6, eaay8562.Jansen, J., Thornton, B.F., Cortés, A., Sn??lv, J., Wik, M., MacIntyre, S., Crill, P.M., 2020. Drivers of diffusive CH4 emissions from shallow subarctic lakes on daily to multi-year timescales. Biogeosciences 17, 1911-1932.Kordella, S., Ciotoli, G., Dimas, X., Papatheodorou, G., Etiope, G., 2020. Increased methane emission from natural gas seepage at Katakolo Harbour (Western Greece). Applied Geochemistry 116, 104578.Lin, Z.-Y., Chen, H.-W., Lin, H.-J., 2020. Trophic model of a deep-sea ecosystem with methane seeps in the South China Sea. Deep Sea Research Part I: Oceanographic Research Papers 159, 103251.Prouty, N.G., Campbell, P.L., Close, H.G., Biddle, J.F., Beckmann, S., 2020. Molecular indicators of methane metabolisms at cold seeps along the United States Atlantic Margin. Chemical Geology 543, 119603.Queiroz, L.L., Bendia, A.G., Duarte, R.T.D., das Gra?as, D.A., da Costa da Silva, A.L., Nakayama, C.R., Sumida, P.Y., Lima, A.O.S., Nagano, Y., Fujikura, K., Kitazato, H., Pellizari, V.H., 2020. Bacterial diversity in deep-sea sediments under influence of asphalt seep at the S?o Paulo Plateau. Antonie van Leeuwenhoek 113, 707-717.Thiagarajan, N., Crémière, A., Bl?ttler, C., Lepland, A., Kirsim?e, K., Higgins, J., Brunstad, H., Eiler, J., 2020. Stable and clumped isotope characterization of authigenic carbonates in methane cold seep environments. Geochimica et Cosmochimica Acta 279, 204-219.Xu, W., Zheng, G., Martinelli, G., Ma, X., Fortin, D., Fan, Q., Chen, Z., 2020. Mineralogical and geochemical characteristics of hydrocarbon-bleached rocks in Baiyanggou mud volcanoes, Xinjiang, NW China. Applied Geochemistry 116, 104572.Zhang, Y., Gautam, R., Pandey, S., Omara, M., Maasakkers, J.D., Sadavarte, P., Lyon, D., Nesser, H., Sulprizio, M.P., Varon, D.J., Zhang, R., Houweling, S., Zavala-Araiza, D., Alvarez, R.A., Lorente, A., Hamburg, S.P., Aben, I., Jacob, D.J., 2020. Quantifying methane emissions from the largest oil-producing basin in the United States from space. Science Advances 6, eaaz5120.Zhao, R., Summers, Z.M., Christman, G.D., Yoshimura, K.M., Biddle, J.F., 2020. Metagenomic views of microbial dynamics influenced by hydrocarbon seepage in sediments of the?Gulf of Mexico. Scientific Reports 10, 5772.AbstractsAbarghani, A., Gentzis, T., Liu, B., Hohlbauch, S., Griffin, D., Bubach, B., Shokouhimehr, M., Ostadhassan, M., 2020. Bacterial vs. thermal degradation of algal matter: Analysis from a physicochemical perspective. International Journal of Coal Geology 223, 103465. are ubiquitous in all depositional environments, especially in marine environments where anoxic/euxinic conditions prevail. In such environments, sulfate-reducing bacteria play a critical role to supply sulfur as a biogenic source for H2S through biomass degradation. In the biodegradation process, chemical and mechanical properties of the organic matter alter. In order to document these variations in-situ, selected samples from a deeply buried mudrock (Bakken Formation), were examined through microscopy analysis. Two separate but adjacent telalginite particles were selected; An unaltered telalginite and a bacterially degraded telalginite, which still contains relicts of the parent Tasmanites. A combination of AFM-based IR spectroscopy with high-resolution amplitude-frequency modulation was used to evaluate and compare the physicochemical variations across these two particles at the nanoscale. Results indicate that all aromaticity indexes increase for both particles but at a higher rate as a result of bacterial degradation. Furthermore, it was found that bacterial degradation imposes a major mechanical heterogeneity to the organic matter under study, which was detected through phase imaging and modulus mapping captured from submicron to micron-scale level, which exposed the remnants of the parent Tasmanites. This study reveals that bacterial degradation can accelerate the maturation process, thus the generation of hydrocarbons from the kerogen to happen at the earlier stages of thermal adavance.Abba, S.I., Usman, A.G., I?ik, S., 2020. Simulation for response surface in the HPLC optimization method development using artificial intelligence models: A data-driven approach. Chemometrics and Intelligent Laboratory Systems 201, 104007. this paper, three different data-driven algorithms were employed including two nonlinear models (Artificial neural network (ANN) and Adaptive neuro-fuzzy inference system (ANFIS)) and a classical linear model (Multilinear regression analysis (MLR)) for the simulation of response surface for methyclothiazide (M) and amiloride (A) considered as (K’or k) modeling in HPCL using pH and composition of mobile phase (methanol) as the corresponding input variables. The experimental and simulated results were evaluated based on five different performance efficiency criteria namely; determination coefficient (R2), root mean square error (RMSE), correlation coefficient (R), mean square error (MSE) and mean absolute percentage error (MAPE). The obtained results demonstrated the promising ability of ANN and ANFIS over MLR models with average R-values of 0.95 in both training and testing phases. The results also indicated that, with regard to the percentage error, ANN and ANFIS models outperformed the MLR model and increased the accuracy up to 6% and 8%, respectively for K’ ? (M) simulation, while for K’ (A), ANFIS increased the accuracy up to 5% and 4% for MLR and ANN, respectively. The overall results proved the reliability of artificial intelligence models (ANN and ANFIS) for the simulation of response surface optimization method.Abdel-Rehim, M., Pedersen-Bjergaard, S., Abdel-Rehim, A., Lucena, R., Moein, M.M., Cárdenas, S., Miró, M., 2020. Microextraction approaches for bioanalytical applications: An overview. Journal of Chromatography A 1616, 460790. samples are usually complex matrices due to the presence of proteins, salts and a variety of organic compounds with chemical properties similar to those of the target analytes. Therefore, sample preparation is often mandatory in order to isolate the analytes from troublesome matrices before instrumental analysis. Because the number of samples in drug development, doping analysis, forensic science, toxicological analysis, and preclinical and clinical assays is steadily increasing, novel high throughput sample preparation approaches are calling for. The key factors in this development are the miniaturization and the automation of the sample preparation approaches so as to cope with most of the twelve principles of green chemistry. In this review, recent trends in sample preparation and novel strategies will be discussed in detail with particular focus on sorptive and liquid-phase microextraction in bioanalysis. The actual applicability of selective sorbents is also considered. Additionally, the role of 3D printing in microextraction for bioanalytical methods will be pinpointed.Abutaqiya, M.I.L., Sisco, C.J., Khemka, Y., Safa, M.A., Ghloum, E.F., Rashed, A.M., Gharbi, R., Santhanagopalan, S., Al-Qahtani, M., Al-Kandari, E., Vargas, F.M., 2020. Accurate modeling of asphaltene onset pressure in crude oils under gas injection using Peng–Robinson equation of state. Energy & Fuels 34, 4055-4070. precipitation is considered a precursor of the plugging of oil wells and subsurface equipment and is a topic of continuous interest among companies and academic institutions. Numerous models to predict asphaltene precipitation at reservoir conditions have emerged over the years, and some have been dropped for several reasons. One particular case is the utilization of cubic equations of state such as Peng–Robinson (PR) and Soave–Redlich–Kwong (SRK), which although are relatively simple to code and utilize, have not been as effective in predicting asphaltene precipitation as compared to other models such as the perturbed chain version of the statistical associating fluid theory equation of state (PC-SAFT EOS). However, we have found that after improving the crude oil characterization procedure to obtain a proper set of simulation parameters from the available experimental data, the cubic equation of state can show excellent predictive capabilities in modeling asphaltene onset pressure under gas injection. In this work, we develop a characterization methodology based on the contents of Saturates–Aromatics–Resins–Asphaltenes (SARA) that can be used with PR EOS. Several case studies with published data from six crude oils are conducted to assess the predictive capability of the new approach in modeling asphaltene onset pressure under gas injection. Comparisons are made with PC-SAFT EOS to highlight the advantages and disadvantages of each model. Also, the modeling approach is tested against high-pressure and high-temperature data from four wells from the Middle East that have not been previously published in the literature. The results indicate that PR EOS yields results that are at least as good as those obtained from PC-SAFT in predicting the onset of asphaltene precipitation in crude oil under various amounts and types of gas injection.Abutaqiya, M.I.L., Sisco, C.J., Vargas, F.M., 2020. A predictive thermodynamic framework for modeling density and phase behavior of petroleum fluids. Energy & Fuels 34, 4497-4507. a recent work, we proposed correlations relating the perturbed-chain statistical associating fluid theory (PC-SAFT) parameters for nonpolar substances to simple measurements of molecular weight and density at ambient conditions (Abutaqiya et al., I&EC Research2020,59(2), 930–941). These parameter relations were shown to accurately reproduce volumetric and phase equilibrium properties for systems containing defined components. In this work, the newly developed PC-SAFT parameter correlations are used to model the thermodynamic properties of crude oils and petroleum fuels. The proposed modeling framework relies on treating the heavy fraction as a single pseudocomponent whose PC-SAFT parameters are calculated from the measured molecular weight and density at 20 °C and 1 atm. This approach does not require the saturate–aromatic–resin–asphaltene analysis or the hydrogen/carbon ratio of the fluid. In fact, the modeling approach is predictive and does not require any tuning parameters. The proposed framework is applied to 5 petroleum fuels, 3 dead oils, and 32 live oils from the literature. Density predictions for the studied hydrocarbon mixtures show an average absolute percent deviation (AAPD) of 0.8% (1230 data points), and the bubble pressure predictions for live oils and their gas blends show an AAPD of 5.02% (113 data points).Adeyilola, A., Nordeng, S., Onwumelu, C., Nwachukwu, F., Gentzis, T., 2020. Geochemical, petrographic and petrophysical characterization of the Lower Bakken Shale, Divide County, North Dakota. International Journal of Coal Geology 224, 103477. Lower Bakken Shale is a key member of the Bakken Petroleum System, which is a prolific unconventional accumulation in North America. Unconventional accumulations have unpredictable lateral variations in hydrocarbon production due to a variety of factors including porosity, permeability, and other rock properties. Therefore, understanding the geochemical (source rock potential), petrological, and petrophysical properties of these units is essential in evaluating the hydrocarbon potential for the Lower Bakken Shale. This study utilized cores from four wells within three fields in Divide County, North Dakota, with samples collected for Rock- Eval pyrolysis, organic petrology, petrographic thin section studies, XRD, SEM, porosity, pore size, and pore fluid distribution. Helium porosimetry and NMR T2 porosity techniques were used to estimate porosity and also to check the quality of the results and avoid discrepancies. Results showed that maturity in the study area varies from immature to early mature using Tmax and solid bitumen reflectance. Organic petrology showed the dominance of solid bitumen and marine alginites, which confirms the Type II kerogen identified from pyrolysis and marine depositional environment in the study area. Major organic matter types identified from SEM studies involve stringy OM, OM-mineral admixture, particulate OM and pure OM which host the majority of the organic matter pores. Furthermore, pore types identified from SEM include mineral matrix pores, organic matter pores, and microfracture pores. Porosity values based on both helium and NMR varies but the difference was nominal and attributed to the presence of abundant clay minerals. Pore sizes are distributed within micropores, mesopores, and macropores with thermal maturity, TOC, and clay mineral proportion having a major influence on pore distribution. Clay-bound water was identified to be the dominant fluid within the shale samples using the T2 cutoff values and supporting evidence from the abundance of clay matrix porosity.Afra, S., Samouei, H., Golshahi, N., Nasr-El-Din, H., 2020. Alterations of asphaltenes chemical structure due to carbon dioxide injection. Fuel 272, 117708. precipitation during carbon dioxide injection to enhance recovery has been considered as one of the major challenges in the tertiary production phase. The effects of CO2 injection on asphaltenes chemical structure and stability in the matrix has not been fully understood yet. The present study aims to characterize asphaltenes structural alterations in the presence of CO2 at high temperature and pressure and then elaborates the mechanism in which these changes affect asphaltenes stability in the matrix. The chemical structure of four precipitated asphaltenes in the presence and absence of CO2 were characterized and compared. These results were coupled with the results of the stability assessment to determine the effects of structural alteration on asphaltenes stability in crude oil. Infrared (IR) spectroscopy results demonstrated the formation of amide functional group upon CO2 injection to the model oil. The precursor of such an observation is characterized to be the reaction of CO2 with amine functional group of the asphaltenes sample. Such a reaction led to the decrease of asphaltenes stability in the model oil sample. The results of the present study suggest that asphaltenes can be destabilized in the oil matrix through both chemical reactions and physical interactions. The presence of chemical functional groups that can react with CO2 in the reservoir conditions is the primary trigger to initiate asphaltenes destabilization. These findings can be used to further research asphaltenes disturbing mechanisms at the molecular level and scale them up to understand asphaltenes physical behaviors during CO2 injection.Akam, S.A., Coffin, R.B., Abdulla, H.A.N., Lyons, T.W., 2020. Dissolved inorganic carbon pump in methane-charged shallow marine sediments: State of the art and new model perspectives. Frontiers in Marine Science 7, 206. doi: 10.3389/fmars.2020.00206. transport from subsurface reservoirs to shallow marine sediment is characterized by unique biogeochemical interactions significant for ocean chemistry. Sulfate-Methane Transition Zone (SMTZ) is an important diagenetic front in the sediment column that quantitatively consumes the diffusive methane fluxes from deep methanogenic sources toward shallow marine sediments via sulfate-driven anaerobic oxidation of methane (AOM). Recent global compilation from diffusion-controlled marine settings suggests methane from below and sulfate from above fluxing into the SMTZ at an estimated rate of 3.8 and 5.3 Tmol year–1, respectively, and wider estimate for methane flux ranges from 1 to 19 Tmol year–1. AOM converts the methane carbon to dissolved inorganic carbon (DIC) at the SMTZ. Organoclastic sulfate reduction (OSR) and deep-DIC fluxes from methanogenic zones contribute additional DIC to the shallow sediments. Here, we provide a quantification of 8.7 Tmol year–1 DIC entering the methane-charged shallow sediments due to AOM, OSR, and the deep-DIC flux (range 6.4–10.2 Tmol year–1). Of this total DIC pool, an estimated 6.5 Tmol year–1 flows toward the water column (range: 3.2–9.2 Tmol year–1), and 1.7 Tmol year–1 enters the authigenic carbonate phases (range: 0.6–3.6 Tmol year–1). This summary highlights that carbonate authigenesis in settings dominated by diffusive methane fluxes is a significant component of marine carbon burial, comparable to ～15% of carbonate accumulation on continental shelves and in the abyssal ocean, respectively. Further, the DIC outflux through the SMTZ is comparable to ～20% of global riverine DIC flux to oceans. This DIC outflux will contribute alkalinity or CO2 in different proportions to the water column, depending on the rates of authigenic carbonate precipitation and sulfide oxidation and will significantly impact ocean chemistry and potentially atmospheric CO2. Settings with substantial carbonate precipitation and sulfide oxidation at present are contributing CO2 and thus to ocean acidification. Our synthesis emphasizes the importance of SMTZ as not only a methane sink but also an important diagenetic front for global DIC cycling. We further underscore the need to incorporate a DIC pump in methane-charged shallow marine sediments to models for coastal and geologic carbon cycling.Al-Salem, S.M., Uddin, S., Al-Yamani, F., 2020. An assessment of microplastics threat to the marine environment: A short review in context of the Arabian/Persian Gulf. Marine Environmental Research 159, 104961. are recognised as a (persistent) pollutant and are believed to be ubiquitous in the marine environment. The importance of this issue is evident from the large number of technical publications and research efforts within the past decade. However, the Arabian (Persian) Gulf region has few reported datasets in spite of being an area with excessive plastic use and a hefty generation rate of plastic solid waste. This communication aims at stimulating a discussion on this topic focusing on the available regional and international datasets, along with the environmental conditions that are likely to contribute to the disintegration and transport of the plastic debris rendering it as microplastic. This work also highlights some of the constraints in sampling techniques, identification methods, and the reported units of microplastics. Most studies employ neuston nets of variable dimensions that samples different thicknesses of surface water, which also posses a major constraint in standardising field sample collection. Extrapolation of a trawl to units such as particles.km?2 without considering the fact that neuston nets collect three-dimensional samples, is also another aspect discussed in this communication. This study also intends to initiate a discussion on standardising the practices across the region to enable an intercomparison of the reported data. In addition, it calls for a comprehensive assessment using the standardized methodology for putting a mitigation plan for microplastics as a potential threat detected in environmental sinks.Albini, M., Ridolfi, S., Giuliani, C., Pascucci, M., Staccioli, M.P., Riccucci, C., 2020. Multi-spectroscopic approach for the non-invasive characterization of paintings on metal surfaces. Frontiers in Chemistry 8, 289. doi: 10.3389/fchem.2020.00289. aim of this study is to propose a non-invasive multi-spectroscopic approach for the characterization of oil painting artworks that use a copper plates as substrate in place of a canvas. Indeed, in the last decade, many studies have been conducted on artworks made of single materials (e.g., paintings, stones, metals). However, the characterization and conservation of composite artifacts has never be fully investigated even though many masterpieces were created using this particular technique. In this work, several spectroscopic techniques such as Infrared Spectroscopy (FTIR), Energy-Dispersive X-Ray Fluorescence spectroscopy (EDXRF), and high spatial resolution Field Emission Scanning Electron Microscopy coupled with Energy Dispersive X-ray Spectroscopy (EDS), and Optical Microscopy (OM) were performed. The obtained results allowed to fully characterize the micro-chemical and microstructural features of the painted surfaces and of the metal plate. Particularly effective was the use of MA-XRF, resulting in the chemical map of the painted surfaces. Furthermore, traces of the mechanical preparation of the plate were found under the painted layers. Finally, the interface area between the paint film and the metallic support was characterized at a micro scale. This was particularly important in order to identify the degradation products formed by the interaction between the fatty acids of the binder and copper-based substrates.Aléon, J., Aléon-Toppani, A., Platevoet, B., Bardintzeff, J.-M., McKeegan, K.D., Brisset, F., 2020. Alkali magmatism on a carbonaceous chondrite planetesimal. Proceedings of the National Academy of Sciences 117, 8353-8359.: In spite of magnetic and isotopic evidence revealing connections between the most primitive outer Solar System materials and differentiated bodies with a layered structure akin to terrestrial planets, the meteoritic record lacks samples that document the initiation of partial melting and the onset of planetary differentiation. Here, we describe a trachybasalt formed by very limited partial melting of a carbonaceous chondrite and crystallized as a dyke during ascent through the chondritic crust. This sample testifies of partial differentiation of outer Solar System carbonaceous planetesimals and can be considered as the long-sought first melt produced in differentiating small bodies.Abstract: Recent isotopic and paleomagnetic data point to a possible connection between carbonaceous chondrites and differentiated planetary materials, suggesting the existence, perhaps ephemeral, of transitional objects with a layered structure whereby a metal-rich core is enclosed by a silicate mantle, which is itself overlain by a crust containing an outermost layer of primitive solar nebula materials. This idea has not received broad support, mostly because of a lack of samples in the meteoritic record that document incipient melting at the onset of planetary differentiation. Here, we report the discovery and the petrologic–isotopic characterization of UH154-11, a ferroan trachybasalt fragment enclosed in a Renazzo-type carbonaceous chondrite (CR). Its chemical and oxygen isotopic compositions are consistent with very-low-degree partial melting of a Vigarano-type carbonaceous chondrite (CV) from the oxidized subgroup at a depth where fluid-assisted metamorphism enhanced the Na content. Its microdoleritic texture indicates crystallization at an increasing cooling rate, such as would occur during magma ascent through a chondritic crust. This represents direct evidence of magmatic activity in a carbonaceous asteroid on the verge of differentiating and demonstrates that some primitive outer Solar System objects related to icy asteroids and comets underwent a phase of magmatic activity early in the Solar System. With its peculiar petrology, UH154-11 can be considered the long-sought first melt produced during partial differentiation of a carbonaceous chondritic planetary body, bridging a previously persistent gap in differentiation processes from icy cometary bodies to fully melted iron meteorites with isotopic affinities to carbonaceous chondrites.AlQuraishi, A.A., AlLaboun, A., AlGhamdi, F., AlHussinan, S., 2020. Silurian Qusaiba Shale: Petrophysical, mineralogical and geochemical analysis. Journal of Petroleum Science and Engineering 192, 107209. organic rich Lower Silurian Qusaiba Shale is the main effective source rock for most of the Paleozoic hydrocarbon in Eastern and central Arabia. Outcrop samples were obtained from Tayma quadrangle, northwest Saudi Arabia and extensive analyses were performed including petrophysical, geochemical, mineralogical, elemental, paleontological and lithofacies identification. Visual observation of samples tested shows highly cemented, thinly laminated and silty micaceous shale, light to dark grey in color with wide range of grain size. Paleontological analysis indicates no trace of micro or macrofossils presence in the studied samples. Elemental XRF analysis indicates major oxides of silica, calcium and alumina, reflecting the composition of the shale samples detected by XRD analysis. Silica sulfur, potassium, calcium, magnesium, titanium and high iron content reflect the presence of the quartz, pyrite, biotite, anhydride, clay minerals and iron oxides. The chemical index of alteration (CIA) and the chemical index of weathering (CIW) indicate relatively deep marine paleoclimate environment with intermediate to strong weathering conditions. High iron contents and presence of traces of titanium oxides confirm the mafic source of these shales. The lithofacies variation and mineralogy were tested using SEM/EDS and different pore systems namely organic, non-organic, and micro-fractures were recognized. Image processing indicate the presence of large macro size organic pores and Mercury Intrusion Porosmetry supports that indicating one meso and three macro pore size ranges with average porosity and permeability of 7.8% and 1.56 nD respectively. Geochemical analysis shows TOC slightly over 2?mg/g indicating good hydrocarbon generation potential with low S2 and HI values, indicating mature kerogen with gas prone type III. The results obtained confirm the potential of the Qusaiba shale and provide more insight on the characteristics of this formation.Alsaba, M.T., Al Dushaishi, M.F., Abbas, A.K., 2020. A comprehensive review of nanoparticles applications in the oil and gas industry. Journal of Petroleum Exploration and Production Technology 10, 1389-1399. the increased attention toward nanotechnology and their innovative use for different industries including but not limited to food, biomedical, electronics, materials, etc, the application of nanotechnology or nanoparticles in the oil and gas industry is a subject undergoing intense study by major oil companies, which is reflected through the huge amount of funds invested on the research and development, with respect to the nanotechnology. Nanotechnology has been recently investigated extensively for different applications in the oil and gas industry such as drilling fluids and enhanced oil recovery in addition to other applications including cementing and well stimulation. In this paper, comprehensive literature was conducted to review the different applications of nanotechnology in the oil and gas industry. A summary of all nanoparticles used along with a detailed analysis of their performance in improving the targeted parameters is comprehensively presented. The main objective of this review was to provide a comprehensive summary of the different successful applications of nanotechnology and its associated challenges, which could be very helpful for future researches and applications.Alvarez, V.M., Guimar?es, C.R., Jurelevicius, D., de Castilho, L.V.A., de Sousa, J.S., da Mota, F.F., Freire, D.M.G., Seldin, L., 2020. Microbial enhanced oil recovery potential of surfactin-producing Bacillus subtilis AB2.0. Fuel 272, 117730. subtilis AB2.0 showed to produce a surface-active compound that was identified by mass spectrometry analysis as a surfactin. Four different isoforms were identified in the protonated form [M+H]+ with m/z of 1030.6350, 1044.6511, 1058.6661 and 1072.6848. They were constituted of fatty acids varying from C13 to C16; however, about 70% of the isoforms showed m/z of 1058.6661 and the fatty acid C15. Based on the AB2.0 genome sequence, only one gene group related to surfactin biosynthesis was found. Strain AB2.0 produced 99.6 mg/l of surfactin in Tryptic Soy Broth after 48 h. The biosurfactant presented an emulsification activity of 45.7% in this growth condition. It considerably decreased the water surface tension from 72.0 mN/m to 24.7 mN/m and the interfacial tension of n-hexadecane from 30.1 mN/m to 7.5 mN/m, as well as of a medium crude oil from 42.3 mN/m to 6.9 mN/m and of a light crude oil from 36.4 to 3.8 mN/m. Calcite flotation test was conducted to access the wettability reversal of the biosurfactant in high salinity condition similar to that observed in an oil production reservoir, and AB2.0 reversed 100% using concentrations as low as 25 ppm of biosurfactant. Oil contaminated sand columns were used to simulate microbial enhanced oil recovery at different temperatures and high salinity. When surfactin from AB2.0 was added to the sand columns, the TPH concentration in liquid phases recovered was enhanced up to 24× indicating that AB2.0 is an excellent candidate for its application in MEOR in subsurface environments.Alves, G., Yu, Y.-K., 2020. Robust accurate identification and biomass estimates of microorganisms via tandem mass spectrometry. Journal of the American Society for Mass Spectrometry 31, 85-102. and accurate identification of microorganisms and estimation of their biomasses are of extreme importance to public health. Mass spectrometry has become an important technique for these purposes. Previously we published a workflow named Microorganism Classification and Identification (MiCId v.12.26.2017) that was shown to perform no worse than other workflows. This manuscript presents MiCId v.12.13.2018 that, in comparison with the earlier version v.12.26.2017, allows for biomass estimates, provides more accurate microorganism identifications (better controls the number of false positives), and is robust against database size increase. This significant advance is made possible by several new ingredients introduced: first, we apply a modified expectation-maximization method to compute for each taxon considered a prior probability, which can be used for biomass estimate; second, we introduce a new concept called ownership, through which the participation ratio is computed and use it as the number of taxa to be kept within a cluster of closely related taxa; third, based on confidently identified peptides, we calculate for each taxon its degree of independence from the rest of taxa considered to determine whether or not to split this taxon off the cluster. Using 270 data files, each containing a large number of MS/MS spectra, we show that, in comparison with v.12.26.2017, version v.12.13.2018 yields superior retrieval results. We also show that MiCId v.12.13.2018 can estimate species biomass reasonably well. The new MiCId v.12.13.2018, designed to run in Linux environment, is freely available for download at Khodja, F., Sassiat, P., Hanafi, M., Thiebaut, D., Vial, J., 2020. A promising "metastable" liquid crystal stationary phase for gas chromatography. Journal of Chromatography A 1616, 460786. liquid crystal state is an ordered physical state between a solid and a liquid. Previous research, in gas chromatography, proved that it provides a geometric selectivity, which allows the separation of geometric position isomers and cis-trans isomers that are difficult to separate on conventional gas chromatography stationary phases (polydimethyl siloxane derived and polyethylene glycol stationary phases). However, their use was generally very limited by the rather high temperature at which they must be operated, normally above the solid-liquid crystal transition temperature. In the present study we are interested in a new synthesized material, 1,4- bis (4-bromohexyloxy benzoate) phenyl (BHOBP). The first characterizations of BHOBP were carried out by thermogravimetric analysis, hot-stage optical microscopy and differential scanning calorimetry to control the thermal stability of the BHOBP as well as the nematic texture of the mesophase highlighted in a well-defined temperature range (120?°C-200?°C). When heated, the solid compound led to a stable liquid crystal state. Its cooling has revealed "a new metastable physical state, which is the supercooled liquid crystal phase". After these first characterizations, the new material was used as a stationary phase for gas chromatography. The BHOBP was deposited in a capillary column by the dynamic method. The inverse gas chromatography study of the column revealed a solid-stable nematic phase transition temperature, in agreement with the first characterization methods. The stable liquid crystal phase showed good resolutions in the analysis of some geometric isomers of low volatility as PAHs. The presence of the supercooled liquid crystal state in the chromatographic column has also been confirmed. This new metastable state is particularly interesting because it enlarged the scope of this material by improving the resolution of several mixtures. Thus, the separation of highly volatile mixtures of geometric isomers (e.g. cis and trans-decalin) was achieved only through this metastable mesophase confirming its unique selectivity. The metastable liquid crystal, used at 80?°C, has also exhibited an original behavior by its stability after several weeks of use at the same temperature, maintaining constant retention factors and selectivity.Ansari, S., Sabbagh, R., Yusuf, Y., Nobes, D.S., 2020. The role of emulsions in steam-assisted-gravity-drainage (SAGD) oil-production process: A review. SPE Journal 25, 969-989. that investigate and attempt to model the process of steam-assisted gravity drainage (SAGD) for heavy-oil extraction often adopt the single-phase-flow assumption or relative permeability of the moving phases as a continuous phase in their analyses. Looking at the emulsification process and the likelihood of its prevalence in SAGD, however, indicates that it forms an important part of the entire physics of the process. To explore the validity of this assumption, a review of prior publications that are related to the SAGD process and the modeling approaches used, as well as works that studied the emulsification process at reservoir conditions, is presented. Reservoir conditions are assessed to identify whether the effect of the emulsion is strong enough to encourage using a multiphase instead of a single-phase assumption for the modeling of the process. The effect of operating conditions on the stability of emulsions in the formation is discussed. The review also covers the nature and extent of effects from emulsions on the flow mechanics through pore spaces and other flow passages that result from the well completion and downhole tubing, such as sand/flow-control devices. The primary outcome of this review strengthens the idea that a multiphase-flow scenario needs to be considered when studying all flow-related phenomena in enhanced-oil-recovery processes and, hence, in SAGD. The presence of emulsions significantly affects the bulk properties of the porous media, such as relative permeability, and properties that are related to the flow, such as viscosity, density, and ultimately pressure drop. It is asserted that the flow of emulsions strongly contributed to the transport of fines that might cause plugging of either the pore space or the screen on the sand-control device. The qualitative description of these influences and their extents found from the review of this large area of research is expected to guide activities during the conception stages of research questions and other investigations.Anto, R., Deshmukh, S., Sanyal, S., Bhui, U.K., 2020. Nanoparticles as flow improver of petroleum crudes: Study on temperature-dependent steady-state and dynamic rheological behavior of crude oils. Fuel 275, 117873. the present energy scenario, the oil companies are persuading to exploit crude oil resources with high viscosity and an extreme chemical composition which makes production and transportation complex. The rheology of crude oil is related to the chemical components present in them where the molecular structure of polar polycyclic aromatic hydrocarbon (PAH) plays an important role. The emergence of nanotechnology in this aspect may provide a better solution for production optimization from the subsurface reservoir as well as flow assurance in surface transportation. The present study investigates the rheological behavior of two crude oils that are chemically different at the molecular level which is demonstrated by spectroscopic methods viz. UV–visible, Fluorescence and FTIR spectroscopy. Steady-state and dynamic rheological experiments carried out with nanoparticle-free and nanoparticles added crude oil clearly exhibits that at different temperature ranges, the nanoparticles help in improving the flow properties by modifying the viscoelastic-network. The silica nanoparticles produced a higher reduction in viscosity compared to alumina nanoparticles and showed different effects on the behavior of both the samples. Thus, nanoparticles could be an important agent for flow assurance, where the proper molecular-level characterization of crude oils would help in selecting the nanoparticles for better performance.Asadzadeh, S., Souza Filho, C.R., 2020. Characterization of microseepage-induced diagenetic changes in the Upper-Red Formation, Qom region, Iran. Part II: A new insight using reflectance spectroscopic analysis. Marine and Petroleum Geology 117, 104387. classic microseepage model supports the notion that hydrocarbon pools leak to the surface over time and trigger an array of diagenetic physicochemical and mineralogical changes in the overlying sediments. Mapping the induced alteration mineralogy for microseepage targeting has been an appealing yet ambiguous practice, mostly because of our incomplete understanding of the diversity of changes occurring in the environment. To close this gap, an integrated spectroscopic approach is adopted here to investigate the variability, quantity, and physicochemistry of diagenetic minerals induced by active microseepage systems over the Alborz oil reservoir in the Qom region, Iran. The area includes an effectively sealed carbonate reservoir overlain by thick Oligocene sediments of the Upper Red Formation. A large suite of samples collected from microseepage-affected zones was spectrally characterized in the 350–2500 nm wavelength region and then statistically contrasted against unaffected samples gathered from a nearby control area. The analysis reveals a novel array of mineralogic indicators for microseepage systems. It indicates that smectites (montmorillonite, nontronite), Al-rich mixed-layer illite/smectite, Fe-rich chlorite and traces of palygorskite constitute the clay alterations. This array is associated with the enrichment of K2O and loss of Na2O and MgO from the system, as indicated by X-ray fluorescence measurements. In the arid climate of the region, the iron-rich red-beds (Fe2O3 > 6%) are only moderately bleached and, thus, the subsequent chemical weathering of the relict irons has triggered goethite (Al-poor), and likely ferrihydrite and maghemite precipitation. Consequently, besides the typical ferric iron bleaching, the modification in the mineralogy of iron oxides/oxyhydroxides (marked by a shift in the absorption minimum at ~900 nm) is suggested as an additional indicator of microseepage systems. Fe-chlorites constitute the dominant ferrous mineral present in the environment. The affected strata are also associated with prevalent calcite and gypsum cements, and occasionally jarosite occurrences. Based on the silica contents of the host-rock, the microseepage-induced alterations are classified into two categories, namely ‘felsic’ and ‘mafic’, wherein the latter is typified by the assemblages described here. This study provides new insights into microseepage-induced alterations and highlights the significance of reflectance spectroscopic techniques in facies determination and the alteration footprints mapping of onshore microseepage systems.Ashleyu, K., Bendle, J., Crosta, X., Etourneau, J., Campagne, P., Gilchrist, H., Ibraheem, U., Greene, S., Schmidt, S., Eley, Y., Massé, G., 2020. Fatty acid carbon isotopes: a new indicator of marine Antarctic paleoproductivity? Biogeosciences Discussions 2020, 1-26. Antarctic coastal zone is an area of high primary productivity, particularly within coastal polynyas where large phytoplankton blooms and drawdown of CO2 occur. Reconstruction of historical primary productivity changes, and the associated driving factors, could provide baseline insights on the role of these areas as sinks for atmospheric CO2, especially in the context of projected changes in coastal Antarctic sea ice. Here we investigate the potential for using carbon isotopes (δ13C) of fatty acids in marine sediments as a proxy for primary productivity. We use a highly resolved sediment core from off the coast of Adélie Land spanning the last ~?400 years and monitor changes in the concentrations and δ13C of fatty acids along with other proxy data from the same core. We discuss the different possible drivers of their variability and argue that C24 fatty acid δ13C predominantly reflects phytoplankton productivity in open water environments, while C18 fatty acid δ13C reflects productivity in the marginal ice zone. These new proxies have implications for better understanding carbon cycle dynamics in the Antarctica coastal zone in future paleoclimate studies.Attanasi, E.D., Freeman, P.A., 2020. Growth drivers of Bakken oil well productivity. Natural Resources Research 29, 1471-1486. paper identifies the drivers of the phenomenal growth in productivity in hydraulically fractured horizontal oil wells producing from the middle member of the Bakken Formation in North Dakota. The data show a strong underlying spatial component and somewhat weaker temporal component. Drivers of the spatial component are favorable reservoir conditions. The temporal component of well productivity growth is driven by increasing the number of fracture treatments and by increasing the volume of proppant and injection fluids used on a per fracture treatment basis. Random Forest, a nonparametric modeling procedure often applied in the context of machine learning, is used to identify the relative importance of geologic and well completion factors that have driven the growth in Bakken well productivity. The findings of this study suggest that a significant part of the well productivity increases during the period from 2010 to 2015 has been the result of improved well site selection. For the more recent period, that is, from 2015 through 2017, part of the improved well productivity has resulted from substantial increases in the proppant and injection fluids used per stage and per well.Aubineau, J., El Albani, A., Bekker, A., Chi Fru, E., Somogyi, A., Medjoubi, K., Riboulleau, A., Meunier, A., Konhauser, K.O., 2020. Trace element perspective into the ca. 2.1-billion-year-old shallow-marine microbial mats from the Francevillian Group, Gabon. Chemical Geology 543, 119620. sedimentary fabrics of Precambrian mat-related structures (MRS) represent some of the oldest convincing evidence for early life on Earth. The ca. 2.1 billion-year (Ga) old MRS in the FB2 Member of the Francevillian basin in Gabon has received considerable attention not only because they contain remnants of microbial mats that colonized large areas in oxygenated, shallow-marine settings, but they also contain evidence for ancient multicellular organisms that thrived on these microbial mats using them as a food source. Despite these insights, what remains lacking is a full characterization of the geochemical composition of the MRS to test whether the bulk composition of fossilized MRS is distinct from the host sediments (sandstones and shales). Here, we show that the trace element (TE) content of microbial textures belonging to pyritized MRS, poorly pyritized MRS, and “elephant-skin” textures (EST) is highly variable and differs from that of the host sediments. The poorly pyritized MRS contain a unique matrix with embedded Ti- and Zr-rich minerals and syngenetically enriched in TE. The EST, some of which are developed along the same stratigraphic horizon as the poorly pyritized MRS, display a distinct distribution of TE-bearing heavy minerals, suggesting a local difference in physical conditions during sedimentation. Similarly, high chalcophile-element (CE) content in pyritized MRS relative to the host sediments of the FB2 Member further points to local bacterially influenced enrichments with high rates of microbial sulfate reduction during early diagenesis. The geochemical relationship between the MRS and the Francevillian sediments (e.g., FB, FC, and FD formations) indicates that specific biological pathways for CE enrichments (i.e., microbially controlled accumulation) are not apparent. Our findings highlight bulk-rock TE distinction between the 2.1-billion-year-old MRS and their host sediments, but also indicate that environmental conditions, such as hydrodynamic regime and water-column redox chemistry, may simply overwhelm any potential biological signal. Our data suggest that the microbial impact may have only passively influenced TE enrichment in the studied sediments, implying that TE concentrations in MRS are a poor biosignature. Importantly, this work indicates that bulk TE geochemistry does not unveil specific microbiological processes in the rock record, which is consistent with the observed patterns in modern analogues.Auderset, A., Schmitt, M., Martínez-García, A., 2020. Simultaneous extraction and chromatographic separation of n-alkanes and alkenones from glycerol dialkyl glycerol tetraethers via selective Accelerated Solvent Extraction. Organic Geochemistry 143, 103979. method is described for simultaneous extraction and chromatographic separation of saturated hydrocarbons (n-alkanes) and unsaturated long-chain ketones (alkenones) from glycerol dialkyl glycerol tetraethers (GDGTs) using selective accelerated solvent extraction (ASE). We show that the method can be used to successfully separate n-alkanes and alkenones from GDGTs in marine sediment samples and n-alkanes from GDGTs in lake sediments and soil samples. A comparison of our method with analysis of samples purified using classical silica column chromatography demonstrates that the new method does not affect the alkenone unsaturation index (U37K'"U37K'), the TetraEther indeX (TEX86), the Methane Index (MI), the Ring Index (RI), the branched-GDGT-based paleotemperature and soil pH indices, the Branched and Isoprenoid Tetraether (BIT) index, the n-alkane average chain length (ACL) or the carbon preference index (CPI). The new procedure results in higher sample recoveries for n-alkanes and more precise U37K'"U37K' estimates at low concentrations, and contributes to reduced analyst laboratory time.Bagley, M.C., Ekel?f, M., Muddiman, D.C., 2020. Determination of optimal electrospray parameters for lipidomics in infrared-matrix-assisted laser desorption electrospray ionization mass spectrometry imaging. Journal of the American Society for Mass Spectrometry 31, 319-325. matrix-assisted laser desorption ionization (IR-MALDESI) is an ambient mass spectrometry imaging (MSI) technique that relies on electrospray ionization (ESI) for ion generation of desorbed neutrals. Although many mechanisms in IR-MALDESI have been studied in depth, there has not yet been a comprehensive study of how the ESI parameters change the profiles of tissue specific lipids. Acetonitrile (ACN)/water and methanol (MeOH)/water solvent systems and compositions were varied across a series of applied ESI voltages during IR-MALDESI analysis of rat liver tissue. Gradients of 12 min were run from 5 to 95% organic solvent in both positive and negative polarities across 11 voltages between 2.25 and 4.5 kV. These experiments informed longer gradients (25–30 min) across shorter solvent gradient ranges with fewer voltages. Optimal ESI parameters for lipidomics were determined by the number and abundance of detected lipids and the relative proportion of background ions. In positive polarity, the best solvent composition was 60–75% ACN/40–25% H2O with 0.2% formic acid at 3.2 kV applied voltage. The best parameters for negative polarity analysis are 45–55% ACN/55–45% H2O with 1 mM of acetic acid for voltages between 2.25 and 3.2 kV. Using these defined parameters, IR-MALDESI positive polarity lipidomics studies can increase lipid abundances 3-fold, with 15% greater coverage, while an abundance increase of 1.5-fold and 10% more coverage can be achieved relative to commonly used parameters in negative polarity.Bai, H., Khodjaniyazova, S., Garrard, K.P., Muddiman, D.C., 2020. Three-dimensional imaging with infrared matrix-assisted laser desorption electrospray ionization mass spectrometry. Journal of the American Society for Mass Spectrometry 31, 292-297. spectrometry imaging as a field has pushed its frontiers to three dimensions. Most three-dimensional mass spectrometry imaging (3D MSI) approaches require serial sectioning that results in a loss of biological information between analyzed slices and difficulty in reconstruction of 3D images. In this contribution, infrared matrix-assisted laser desorption electrospray ionization (IR-MALDESI) was demonstrated to be applicable for 3D MSI that does not require sectioning because IR laser ablates material on a micrometer scale. A commercially available over-the-counter pharmaceutical was used as a model to demonstrate the feasibility of IR-MALDESI for 3D MSI. Depth resolution (i.e., z-resolution) as a function of laser energy levels and density of ablated material was investigated. The best achievable depth resolution from a pill was 2.3 μm at 0.3 mJ/pulse. 2D and 3D MSI were performed on the tablet to show the distribution of pill-specific molecules. A 3D MSI analysis on a region of interest of 15 × 15 voxels across 50 layers was performed. Our results demonstrate that IR-MALDESI is feasible with 3D MSI on a pill, and future work will be focused on analyses of biological tissues.Bardhan, P., Naqvi, S.W.A., 2020. Nitrogen and carbon cycling over the western continental shelf of India during seasonal anoxia: A stable isotope approach. Journal of Marine Systems 207, 103144. western continental shelf of India (eastern Arabian Sea) houses the world's largest seasonally-occurring coastal low-oxygen zone. The natural abundance of nitrogen and oxygen isotopes in dissolved nitrate were measured along four transects of the shelf (off Mumbai, Goa, Mangalore and Calicut) to gain insights into nitrogen cycling in this system. Carbon and nitrogen isotope abundances in particulate organic matter were also measured to understand sources and cycling of organic matter. Three of the four transects (with the exception of Mumbai transect) experienced fully anoxic (sulphidic) conditions over the inner shelf. Denitrification signals, as indicated by a linear increase of δ15N and δ18O in nitrate in oxygen-deficient waters, were observed off Mumbai, Goa and Mangalore. The occurrence of nitrite oxidation was indicated by a decoupling of stable N and O isotopes of nitrate. The fractionation factor computed was found to be quite low (6.1‰), as compared to open ocean oxygen minimum zones, presumably due to a large contribution (>49%) of benthic denitrification to N-loss. Autochthonous production and phytoplankton composition are proposed to exert major controls on the C isotopic composition of particulate organic matter while nitrate and ammonium seem to control the N-isotope variability. Overall, this study attempts to fill the knowledge gap in terms of N and C stable isotope studies in a system that is otherwise well documented from the biogeochemical point of view.Basafa, M., Hawboldt, K., 2020. Sulfur speciation in soured reservoirs: chemical equilibrium and kinetics. Journal of Petroleum Exploration and Production Technology 10, 1603-1612. souring is a widespread phenomenon in reservoirs undergoing seawater injection. Sulfate in the injected seawater promotes the growth of sulfate-reducing bacteria (SRB) and archaea-generating hydrogen sulfide. However, as the reservoir fluid flows from injection well to topside facilities, reactions involving formation of different sulfur species with intermediate valence states such as elemental sulfur, sulfite, polysulfide ions, and polythionates can occur. A predictive reactive model was developed in this study to investigate the chemical reactivity of sulfur species and their partitioning behavior as a function of temperature, pressure, and pH in a seawater-flooded reservoir. The presence of sulfur species with different oxidation states impacts the amount and partitioning behavior of H2S and, therefore, the extent of reservoir souring. The injected sulfate is reduced to H2S microbially close to the injection well. The generated H2S partitions between phases depending on temperature, pressure, and pH. Without considering chemical reactivity and sulfur speciation, the gas phase under test separator conditions on the surface contains 1080 ppm H2S which is in equilibrium with the oil phase containing 295.7 ppm H2S and water phase with H2S content of 8.8 ppm. These values are higher than those obtained based on reactivity analysis, where sulfur speciation and chemical reactions are included. Under these conditions, the H2S content of the gas, oil, and aqueous phases are 487 ppm, 134 ppm, and 4 ppm, respectively.Batanero, G.L., Green, A.J., Amat, J.A., Vittecoq, M., Suttle, C.A., Reche, I., 2020. Alternation of heterotrophic bacterial and archaeal production along nitrogen and salinity gradients in coastal wetlands. Biogeosciences Discussions 2020, 1-35. wetlands are valuable ecosystems with high biological productivity and diversity, which provide ecosystem services such as a reduction in the inputs of nitrogen into coastal waters, and storage of organic carbon, thus, acting as net carbon sinks. The rise of sea level as a consequence of climatic warming will salinize many coastal wetlands, but there is considerable uncertainty about how salinization will affect microbial communities and biogeochemical processes. We analyzed prokaryotic abundance and heterotrophic bacterial and archaeal production in 112 ponds within nine coastal wetlands from the western Mediterranean coast. We determined the main drivers of prokaryotic abundance and production in these wetlands using generalized linear models (GLMs). The best GLM, including all the coastal wetlands, indicated that the concentration of total dissolved nitrogen (TDN) positively affected the abundance of heterotrophic prokaryotes and heterotrophic archaeal production. In contrast, heterotrophic bacterial production was negatively related to TDN. This negative relationship appeared to be mediated by salinity and virus abundance. Heterotrophic bacterial production declined as salinity, and virus abundance, increased. We observed a switch from heterotrophic bacterial production towards heterotrophic archaeal production as salinity and virus abundance increased. Our results imply that microbial activity will change from bacterial-dominated processes to archaeal-dominated processes along with increases of nitrogen inputs and salinity. However, more studies are required to link the mineralization rates of dissolved nitrogen and organic carbon with specific archaeal taxa, to enable more accurate predictions on future scenarios of wetlands salinization and anthropogenic nitrogen inputs.Beaumont, J., 2020. The whole tooth and nothing but the tooth: Or why temporal resolution of bone collagen may be unreliable. Archaeometry 62, 626-645. carbon (δ13C) and nitrogen (δ15N) isotope ratios of human bone collagen have been used extensively over the last 40?years to investigate the diet of past populations. It has become apparent that bone collagen can give an unreliable temporal dietary signature especially in juveniles. With higher temporal resolution sampling of collagen from tooth dentine, it is possible to identify short‐term changes in diet previously invisible in bone. This paper discusses the inherent problems of using bone collagen for dietary studies and suggests better sample choices, which can make our interpretations more robust, using breastfeeding and weaning as an example.Behera, U.S., Sangwai, J.S., 2020. Synergistic effect of brine system containing mixed monovalent (NaCl, KCl) and divalent (MgCl2, MgSO4) salts on the interfacial tension of pure hydrocarbon-brine system relevant for low salinity water flooding. Energy & Fuels 34, 4201-4212. tension (IFT) plays a vital role in petroleum industry for enhanced oil recovery. In recent years, a new technology called ‘low salinity water flooding’ has brought the attention of researchers because of its ability to alter IFT. However, role of salt types and its impact on the IFT of pure hydrocarbon-water systems are not well understood which could help to develop robust models and process. In the present investigation, we have considered both aliphatic (heptane) and aromatic (toluene) hydrocarbons along with set of nine mixed brine systems containing monovalent (NaCl, KCl) and divalent (MgCl2, MgSO4) salts with wide range of compositions and concentration for IFT studies which are otherwise not reported in the literature. Various combinations of monovalent salts (NaCl:KCl::25:75, NaCl:KCl::50:50, NaCl:KCl::75:25) divalent salts (MgSO4:MgCl2::25:75, MgSO4:MgCl2 ::50:50,MgSO4:MgCl2::75:25), monovalent and divalent salts (NaCl:MgCl2::25:75, NaCl:MgCl2::50:50, NaCl:MgCl2::75:25) along with varying concentrations (0, 500, 750, 1000, 2000, 5000, 10000, 20000ppm) have been used. The experimental result reveals that combination of monovalent (NaCl) and divalent (MgCl2) salt in brine has significant impact on the reduction of IFT of n-heptane-brine system and combination of divalent salts (MgSO4 and MgCl2) show better impact on IFT reduction for toluene-brine system. The mechanism of IFT variation at different salt concentration and composition has also been explained based on Gibbs adsorption isotherm and specific ion effect based on Hofmeister series. The study will be useful to understand the synergetic effect of these salts on the hydrocarbon-brine systems and also will help to develop robust models of IFT suitable for low salinity water flooding and other industrial operations. Beil, S., Kuhnt, W., Holbourn, A., Scholz, F., Oxmann, J., Wallmann, K., Lorenzen, J., Aquit, M., Chellai, E.H., 2020. Cretaceous oceanic anoxic events prolonged by phosphorus cycle feedbacks. Climate of the Past 16, 757-782. anoxic events (OAEs) document major perturbations of the global carbon cycle with repercussions for the Earth's climate and ocean circulation that are relevant to understanding future climate trends. Here, we compare the onset and development of Cretaceous OAE1a and OAE2 in two drill cores with unusually high sedimentation rates from the Vocontian Basin (southern France) and Tarfaya Basin (southern Morocco). OAE1a and OAE2 exhibit remarkable similarities in the evolution of their carbon isotope (δ13C) records, with long-lasting negative excursions preceding the onset of the main positive excursions, supporting the view that both OAEs were triggered by massive emissions of volcanic CO2 into the atmosphere. However, there are substantial differences, notably in the durations of individual phases within the δ13C positive excursions of both OAEs. Based on analysis of cyclic sediment variations, we estimate the duration of individual phases within OAE1a and OAE2. We identify (1) a precursor phase (negative excursion) lasting ～430?kyr for OAE1a and ～130?kyr for OAE2, (2) an onset phase of ～390 and ～70?kyr, (3) a peak phase of ～600 and ～90?kyr, (4) a plateau phase of ～1340 and ～200?kyr, and (5) a recovery phase of ～380 and ～440?kyr. The total duration of the positive δ13C excursion is estimated at 2700?kyr for OAE1a and 790?kyr for OAE2, and that of the main carbon accumulation phase is estimated at 980 and 180?kyr. The long-lasting peak, plateau and recovery phases imply fundamental changes in global nutrient cycles either (1) by submarine basalt–seawater interactions, (2) through excess nutrient inputs to the oceans by increasing continental weathering and river discharge, or (3) through nutrient recycling from the marine sediment reservoir. We investigated the role of phosphorus in the development of carbon accumulation by analysing phosphorus speciation across OAE2 and the mid-Cenomanian Event (MCE) in the Tarfaya Basin. The ratios of organic carbon and total nitrogen to reactive phosphorus (Corg∕Preact and Ntotal∕Preact) prior to OAE2 and the MCE hover close to or below the Redfield ratio characteristic of marine organic matter. Decreases in reactive phosphorus resulting in Corg∕Preact and Ntotal∕Preact above the Redfield ratio during the later phase of OAE2 and the MCE indicate leakage from the sedimentary column into the water column under the influence of intensified and expanded oxygen minimum zones. These results suggest that a positive feedback loop, rooted in the benthic phosphorus cycle, contributed to increased marine productivity and carbon burial over an extended period of time during OAEs.Bekaert, D.V., Broadley, M.W., Marty, B., 2020. The origin and fate of volatile elements on Earth revisited in light of noble gas data obtained from comet 67P/Churyumov-Gerasimenko. Scientific Reports 10, 5796. origin of terrestrial volatiles remains one of the most puzzling questions in planetary sciences. The timing and composition of chondritic and cometary deliveries to Earth has remained enigmatic due to the paucity of reliable measurements of cometary material. This work uses recently measured volatile elemental ratios and noble gas isotope data from comet 67P/Churyumov-Gerasimenko (67P/C-G), in combination with chondritic data from the literature, to reconstruct the composition of Earth’s ancient atmosphere. Comets are found to have contributed ~20% of atmospheric heavy noble gases (i.e., Kr and Xe) but limited amounts of other volatile elements (water, halogens and likely organic materials) to Earth. These cometary noble gases were likely mixed with chondritic - and not solar - sources to form the atmosphere. We show that an ancient atmosphere composed of chondritic and cometary volatiles is more enriched in Xe relative to the modern atmosphere, requiring that 8–12 times the present-day inventory of Xe was lost to space. This potentially resolves the long-standing mystery of Earth’s “missing xenon”, with regards to both Xe elemental depletion and isotopic fractionation in the atmosphere. The inferred Kr/H2O and Xe/H2O of the initial atmosphere suggest that Earth’s surface volatiles might not have been fully delivered by the late accretion of volatile-rich carbonaceous chondrites. Instead, “dry” materials akin to enstatite chondrites potentially constituted a significant source of chondritic volatiles now residing on the Earth’s surface. We outline the working hypotheses, implications and limitations of this model in the last section of this contribution.Bell, E., Lamminm?ki, T., Alneberg, J., Andersson, A.F., Qian, C., Xiong, W., Hettich, R.L., Frutschi, M., Bernier-Latmani, R., 2020. Active sulfur cycling in the terrestrial deep subsurface. The ISME Journal 14, 1260-1272. deep terrestrial subsurface remains an environment where there is limited understanding of the extant microbial metabolisms. At Olkiluoto, Finland, a deep geological repository is under construction for the final storage of spent nuclear fuel. It is therefore critical to evaluate the potential impact microbial metabolism, including sulfide generation, could have upon the safety of the repository. We investigated a deep groundwater where sulfate is present, but groundwater geochemistry suggests limited microbial sulfate-reducing activity. Examination of the microbial community at the genome-level revealed microorganisms with the metabolic capacity for both oxidative and reductive sulfur transformations. Deltaproteobacteria are shown to have the genetic capacity for sulfate reduction and possibly sulfur disproportionation, while Rhizobiaceae, Rhodocyclaceae, Sideroxydans, and Sulfurimonas oxidize reduced sulfur compounds. Further examination of the proteome confirmed an active sulfur cycle, serving for microbial energy generation and growth. Our results reveal that this sulfide-poor groundwater harbors an active microbial community of sulfate-reducing and sulfide-oxidizing bacteria, together mediating a sulfur cycle that remained undetected by geochemical monitoring alone. The ability of sulfide-oxidizing bacteria to limit the accumulation of sulfide was further demonstrated in groundwater incubations and highlights a potential sink for sulfide that could be beneficial for geological repository safety.Bennett, W.W., Canfield, D.E., 2020. Redox-sensitive trace metals as paleoredox proxies: A review and analysis of data from modern sediments. Earth-Science Reviews 204, 103175. trace metals have been used extensively as geochemical proxies to infer the redox-status of marine sediments at the time of their deposition, and by extension, the concentration of oxygen in the overlying water and atmosphere. However, to reliably apply these paleoredox proxies in ancient sediment samples we must calibrate their geochemical behavior in modern sedimentary environments with known redox-status. Here we report a new compilation and analysis of modern trace-metal enrichment data for a range of marine depositional environments, including euxinic basins, continental margin upwelling settings, and normal oxic settings. The enrichments (i.e., concentrations normalized to aluminum content) of vanadium, uranium, molybdenum and rhenium (the VUMoRe database) in the various depositional categories were analyzed using receiver operating characteristic (ROC) curve analysis to systematically identify threshold values that differentiate the various settings. The enrichment of both Mo (> 5 μg g?1/%) and V (> 23 μg g?1/%), but with V not exceeding 46 μg g?1/%, provides strong evidence for a euxinic basin-type depositional environment. Furthermore, the enrichment of V (> 46 μg g?1/%), U (> 5 μg g?1/%) and Mo (> 5 μg g?1/%) is strong evidence for sediments depositing within the anoxic core of perennial OMZ environments, whereas the enrichment of U (> 1 μg g?1/%) coinciding with a low enrichment of V (< 23 μg g?1/%) and Mo (< 5 μg g?1/%) is strong evidence of sediment deposition in the oxic water beneath the core of a perennial OMZ environment. The new method we describe here for determining enrichment thresholds of trace metal-based redox proxies will support the reliable classification of ancient depositional environments and the ongoing development of trace metals as paleoredox proxies.Bepari, K.F., Shenoy, D.M., Chndrasekhara Rao, A.V., Kurian, S., Gauns, M.U., Naik, B.R., Naqvi, S.W.A., 2020. Dynamics of dimethylsulphide and associated compounds in the coastal waters of Goa, west coast of India. Journal of Marine Systems 207, 103228. of total dimethylsulphoniopropionate (DMSPt), Dimethylsulphide (DMS) and total dimethylsulphoxide (DMSOt) were measured at a coastal time series site, west coast of India, from September 2009 to December 2013. While, DMSPt varied between 0.35 and 252?nM (avg. 24?±?32.3?nM), DMS varied from 0.5 to 442?nM (avg. 22.5?±?48.3?nM). The annual phytoplankton regime and succession was observed to play a key role in DMSP and DMS production. DMSPt, DMS and DMSOt showed high temporal variability with maximum concentrations observed during the southwest monsoon (SWM; June to September). While the least DMSP and DMS (<20?nM) concentrations were observed during the northeast monsoon (NEM; December to February) in association with low Chlorophyll a (Chl a), moderate concentrations (40–60?nM) were observed during the spring inter-monsoon (SIM; March to May) in association with diatoms which appear during the senescent phase of the annual Trichodesmium bloom. Moderate concentrations were also observed during the mid-phase of the SWM (July–August) in association with the diatom population. On the other hand, maximum DMSP and DMS observed towards the end of the SWM (September) and fall inter-monsoon (FIM; October) were associated with dinoflagellates, which appear as conditions calm down towards the end of the SWM. There was no correlation between DMSPt and Chl a. High DMS concentrations (up to 442?nM) were observed in the bottom waters during the September of 2009 and 2013 in association with the seasonal anoxia. DMSOt distribution closely resembled that of DMSPt and DMS with an overall variation from 0.56 to 185.9?nM (avg. 27.8?±?30.1?nM). Though wind speeds were highest during July, high DMS flux was observed during September owing to the high surface DMS concentrations. Average surface DMS during the study period was 18.5?nM, whereas average DMS flux was estimated to be 20.9?μmol?S?m?2 D?1. This time series study brings out the importance of hydrography in shaping the phytoplankton population and its influence on the production of DMS.Berends, C.J., de Boer, B., van de Wal, R.S.W., 2020. Reconstructing the evolution of ice sheets, sea level and atmospheric CO2 during the past 3.6 million years. Climate of the Past Discussions 2020, 1-22. the evolution of, and the interactions between, ice sheets and the global climate over geological time is important for being able to constrain earth system sensitivity. However, direct observational evidence of past CO2 concentrations only exists for the past 800?000 years. Records of benthic δ18O date back millions of years, but contain signals from both land ice volume and ocean temperature. In recent years, inverse forward modelling has been developed as a method to disentangle these two signals, resulting in mutually consistent reconstructions of ice volume, temperature and CO2. We use this approach to force a hybrid ice-sheet – climate model with a benthic δ18O stack, reconstructing the evolution of the ice sheets, global mean sea level and atmospheric CO2 during the late Pliocene and the Pleistocene, from 3.6 million years (Myr) ago to the present day. During the warmer-than-present climates of the Late Pliocene, reconstructed CO2 varies widely, from 320–440?ppmv for warm periods such as Marine Isotope Stage (MIS) KM5c, to 235–250?ppmv for the MIS M2 glacial excursion. Sea level is relatively stable during this period, with a high stand of 6–14?m, and a drop of 12–26?m during MIS M2. Both CO2 and sea level are within the wide ranges of values covered by available proxy data for this period. Our results for the Pleistocene agree well with the ice-core CO2 record, as well as with different available sea-level proxy data. During the early Pleistocene, 2.6–1.2?Myr ago, we simulate 40?kyr glacial cycles, with interglacial CO2 decreasing from 280–300?ppmv at the beginning of the Pleistocene, to 250–280?ppmv just before the Mid-Pleistocene Transition (MPT). Peak glacial CO2 decreases from 220–250?ppmv to 205–225?ppmv during this period. After the MPT, when the glacial cycles change from 40?kyr to 80/120?kyr cyclicity, the glacial-interglacial contrast increases, with interglacial CO2 varying between 250–320?ppmv, and peak glacial values decreasing to 170–210?ppmv.Berrier, K.L., Freye, C.E., Billingsley, M.C., Synovec, R.E., 2020. Predictive modeling of aerospace fuel properties using comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry and partial least squares analysis. Energy & Fuels 34, 4084-4094. stringent requirements for aerospace propulsion system performance, reliability, and operability motivate quantitative connections between fuel composition, physical characteristics, and system performance. Chemically accurate assessment of aviation turbine fuels (Jet-A, JP-8, etc.) and kerosene-based rocket propellants (RP-1 and RP-2) is requisite to mature these models. Comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry (GC × GC–TOFMS) is an excellent analytical tool for measuring detailed chemical information contained in complex fuels. Additionally, multivariate data analysis methods, referred to as chemometrics, are ideally suited to relate detailed chemical information contained within the GC × GC–TOFMS data to fuel properties and performance in a predictive manner. Herein, we apply these techniques to a chemically diverse set of 74 distillate and multicomponent aerospace fuels, resulting in an improved understanding of the chemical compositional basis for physical and thermochemical behavior. Informed by GC × GC–TOFMS data, highly reliable partial least squares (PLS) models are developed and employed in the prediction of physical properties (measured separately using conventional test methods). Root-mean-square errors of cross-validation (RMSECV) were relatively low: values of 0.0450 cSt, 41.3 Btu/lbm, 0.130 mass %, and 0.0064 g/mL were obtained for viscosity, heat of combustion, hydrogen content, and density, respectively. The corresponding normalized root-mean-square errors of cross-validation (NRMSECV) were 6.01, 10.3, 8.71, and 7.12%, respectively. Investigation of the linear regression vectors (LRVs) provides valuable insight into the relationship between the chemical composition and physical properties, enabling, in principle, the model-informed selection of fuel chemical composition to achieve desired performance criteria.Bishop, K.G., Garvie-Lok, S., Haagsma, M., MacKinnon, M., Karapanou, S., 2020. Mobile animal management in the Mediterranean: Investigating Hellenistic (323-31 BCE) husbandry practices in Thessaly, Greece using δ13C, δ18O, and 87Sr/86Sr recorded from sheep and goat tooth enamel. Journal of Archaeological Science: Reports 31, 102331. areas where the extent of animal management is debated, stable isotope analysis of animal teeth provides valuable insights into the diet and mobility of herders and their animals. Current research on ancient pastoralism in Thessaly, Greece, is divided over the presence, prevalence, and degree of seasonal livestock movement (transhumance), a discussion often referred to as the agropastoral debate. We present the first application of stable isotope methods to contribute to this discussion, and include a case study from the Hellenistic (323-31 BCE) site of Kastro Kallithea in Thessaly. In particular, we serial sample sheep and goat third molars (M3) recovered from Building 10 and isotopically analyze the resulting enamel segments to record diet (δ13C), seasonality (δ18O), and geolocation (87Sr/86Sr). We integrate the use of stable isotope analysis with archaeological, ethnographic, and literary data to examine various management strategies used in Thessaly. We present evidence of sedentary and seasonally mobile management, including the first recorded cases of transhumant animal management in Thessaly from the Hellenistic period. Each management strategy has corresponding impacts on ancient economy, human ecology, land use, and human-animal relationships. Research of this nature has only just started gaining precedence in Greece, but is a valuable tool for studying the spatiotemporal distribution of shepherding and ultimately recording animal management strategies in the Mediterranean.Blanz, M., Mainland, I., Richards, M., Balasse, M., Ascough, P., Wolfhagen, J., Taggart, M.A., Feldmann, J., 2020. Identifying seaweed consumption by sheep using isotope analysis of their bones and teeth: Modern reference δ13C and δ15N values and their archaeological implications. Journal of Archaeological Science 118, 105140. consumption by wild, feral and domesticated animals in coastal areas world-wide is currently likely widely underestimated. Seaweed consumption on the Orkney Islands by domesticated animals has become an established part of the archaeological literature, but the extent of seaweed consumption elsewhere is still largely unknown in archaeological contexts. The identification of small amounts of seaweed consumption by collagen δ13C and δ15N values remains problematic, as it is unclear to what extent seaweed consumption is reflected in skeletal tissues, and how results may vary between different tissues. In this study, modern sheep consuming known seaweed (predominantly kelp) and terrestrial diets on the Orkney Islands were analysed for δ13Ccollagen, δ15Ncollagen, δ13Cbone apatite and δ13Cenamel to provide a reference for archaeological studies. Seaweed and terrestrial vegetation were also analysed for δ13C and δ15N (n = 122). Seaweed δ15N values did not differ significantly from terrestrial vegetation on North Ronaldsay, indicating that δ15N is not a reliable indicator of seaweed consumption. In contrast, we confirmed that δ13C is a suitable marker for substantial seaweed consumption in all studied tissues in herbivorous diets in the absence of C4 plants. The consumption of both seaweed and terrestrial vegetation led to a large degree of variability in δ13C results (?19.1 to ?11.5‰) within one herd kept under a consistent management system, due to differences in the amount of seaweed consumed by the individual sheep. However, when only small amounts of seaweed are consumed (<25%), this may not be evident in the δ13Ccollagen data. In contrast, when seaweed-consumption occurs primarily in winter, spring-born lambs may be expected to have substantially higher δ13C values than their mothers. This study emphasises the need for modern reference data in archaeology, and may aid the identification of seaweed consumption by herbivores globally.Borisova, O.V., Galstyan, A.G., Olenin, A.Y., Lisichkin, G.V., Zverev, V.V., 2020. Differential diagnostics of bacteria using the surface-enhanced Raman spectra. Microbiology 89, 192-196. Raman scattering of bioorganic compounds close to silver nanoparticles may be used for species identification of microbial colonies. The preparations of silver nanoparticles sol with a single microbial colony (strains Escherichia coli 376/2, Staphylococcus aureus 25923, Pseudomonas aeruginosa ATCC 27583, and Bacillus subtilis 534) exhibited the individual Raman spectra, in which the band occurrence and intensity correlated with the species composition. The most important differences in the spectra of these four strains were associated with the bands at 649?652, 948?950, 1326?1340, and 1468 cm?1. Application of the principal component analysis within the range from 600 to 1600 cm?1 resulted in the sum of the factor load of two major components equal to 83.53% of the total differences between the spectra and demonstrated the possibility of differential diagnostics of four microbial species.Bosch-Orea, C., Sanchís, J., Barceló, D., Farré, M., 2020. Ultra-trace determination of domoic acid in the Ebro Delta estuary by SPE-HILIC-HRMS. Analytical Methods 12, 1966-1974. phytoplankton, such as diatoms, are responsible for a considerable part of carbon fixation and form the basis of the marine food web. However, different factors, such as eutrophication, can affect their population growth and induce the production of toxins. During the last few years, the presence of domoic acid (DA) has increased worldwide in coastal areas. Its toxic properties and capacity to bioaccumulate through the food chain have reinforced the need for developing monitoring strategies to ensure the safety and quality of marine resources. In this work, a highly sensitive analytical method has been developed to be used as an early detection and quantification tool for DA in seawater. The method is based on a sample pre-treatment step by solid-phase extraction (SPE) and an instrumental analysis by hydrophilic interaction liquid chromatography coupled with high-resolution mass spectrometry (HILIC-HRMS). The method has been validated, showing good results in terms of sensitivity and repeatability. Limits of detection and quantification were 0.25 and 0.75 ng L?1 respectively, and acceptable recovery was in the range of 48–69%. Then, the method was applied to study a real scenario in the Ebro Delta where mariculture activities are relevant for the economy of the area. A total of 34 samples were collected in different campaigns during three seasons covering the two main delta bays (Alfacs and Fangar) and four lagoons (La Tancada, Illa de Buda, l'Encanyissada and Canal Vell). 65% of the samples had concentrations of DA at the ng L?1 level, ranging from 0.90 to 69.6 ng L?1. The highest levels were found in samples from Alfacs bay and the summer campaign. In the case of the lagoons, DA was detected only in La Tancada at 8.78 ng L?1 in the winter campaign. This study proves the prevalence of DA in highly eutrophic areas, during all seasons, often at trace level concentrations.Bowman, A.P., Bogie, J.F.J., Hendriks, J.J.A., Haidar, M., Belov, M., Heeren, R.M.A., Ellis, S.R., 2020. Evaluation of lipid coverage and high spatial resolution MALDI-imaging capabilities of oversampling combined with laser post-ionisation. Analytical and Bioanalytical Chemistry 412, 2277-2289. laser desorption/ionisation-mass spectrometry imaging (MALDI-MSI) is a powerful technique for visualising the spatial locations of lipids in biological tissues. However, a major challenge in interpreting the biological significance of local lipid compositions and distributions detected using MALDI-MSI is the difficulty in associating spectra with cellular lipid metabolism within the tissue. By-and-large this is due to the typically limited spatial resolution of MALDI-MSI (30–100 μm) meaning individual spectra represent the average spectrum acquired from multiple adjacent cells, each potentially possessing a unique lipid composition and biological function. The use of oversampling is one promising approach to decrease the sampling area and improve the spatial resolution in MALDI-MSI, but it can suffer from a dramatically decreased sensitivity. In this work we overcome these challenges through the coupling of oversampling MALDI-MSI with laser post-ionisation (MALDI-2). We demonstrate the ability to acquire rich lipid spectra from pixels as small as 6 μm, equivalent to or smaller than the size of typical mammalian cells. Coupled with an approach for automated lipid identification, it is shown that MALDI-2 combined with oversampling at 6 μm pixel size can detect up to three times more lipids and many more lipid classes than even conventional MALDI at 20 μm resolution in the positive-ion mode. Applying this to mouse kidney and human brain tissue containing active multiple sclerosis lesions, where 74 and 147 unique lipids are identified, respectively, the localisation of lipid signals to individual tubuli within the kidney and lipid droplets with lesion-specific macrophages is demonstrated.Bradbury, H.J., Halloran, K.H., Lin, C.Y., Turchyn, A.V., 2020. Calcium isotope fractionation during microbially induced carbonate mineral precipitation. Geochimica et Cosmochimica Acta 277, 37-51. report the calcium isotope fractionation during the microbially-induced precipitation of calcium carbonate minerals in pure cultures of the marine sulfate-reducing bacterium Desulfovibrio bizertensis. These data are used to explore how the calcium isotope fractionation factor during microbially-induced carbonate mineral precipitation differs from the better-constrained calcium isotope fractionation factors during biogenic or abiotic carbonate mineral precipitation. Bacterial growth was then modulated with antibiotics, and the evolution of δ44Ca in solution was monitored under different microbial growth rates. The faster the microbial growth rate, the larger the calcium isotope fractionation during carbonate mineral precipitation, with Δ44Ca(s-f) ranging from ?1.07‰ to ?0.48‰. The reported calcium isotope fractionation can help us understand the link between calcium isotope fractionation and microbial metabolism in carbonate minerals precipitated during sedimentary diagenesis.Brankovits, D., Pohlman, J.W., 2020. Methane oxidation dynamics in a karst subterranean estuary. Geochimica et Cosmochimica Acta 277, 320-333. gradients between fresh, brackish and saline waters shape biogeochemical reactions and organic matter transformation within subterranean estuaries. In the Yucatán Peninsula’s karst subterranean estuary (KSE), methane and dissolved organic matter generated during the anaerobic decomposition of tropical forest vegetation are transported into flooded cave networks where microbial consumption greatly reduces their concentrations in the groundwater. To test the hypothesis that chemoclines associated with salinity gradients of the KSE are sites of methane oxidation, we obtained methane concentration and δ13C profiles of unprecedented vertical resolution from within a fully-submerged cave system located 6.6?km inland from the coastline using the ‘OctoPiPi’ (OPP) water sampler. Along a 12–24?cm thick low-salinity-halocline at ～4.5?m water depth, salinity increased from fresh to brackish (0.2–1.8 psu), methane concentrations decreased, and δ13C values increased, as expected for microbial methane oxidation. The underlying brackish water had elevated oxygen concentrations compared to the always anoxic freshwater, suggesting that aerobic methane oxidation is the dominant process facilitating methane consumption. By contrast, as salinity increased from 1.8 to 36 psu through a 24–36?cm thick high-salinity-halocline between the meteoric lens and the saline groundwater at ～20?m water depth, methane concentrations and δ13C values were constant. Conservative mixing and kinetic isotope models incorporating the methane data confirm a hotspot for microbial methane oxidation at the low-salinity-halocline. At least 98% of methane originating in the anoxic freshwaters was removed before its transport via channelized flow towards the coastline. These findings provide novel insight into the spatial constraints of methane dynamics within a karst subterranean estuary.Braun, M., Kappenberg, A., Sandhage-Hofmann, A., Lehndorff, E., 2020. Leachable soil black carbon after biochar application. Organic Geochemistry 143, 103996. carbon (BC) enters soil via deposition of emissions and nowadays also via application of biochar. Recent studies indicate that a yet not quantified part of BC is lost from soil by leaching, which implies that BC exists in water-transportable form (so-called water-extractable BC; WEBC). We aim at quantifying the amount of WEBC in soil and at elucidating whether it relates to biochar application. The composition of WEBC was further tested to evaluate the degree of BC weathering over time after application, hypothesizing that BC degrades into smaller polyaromatic units. We analysed total BC and WEBC in topsoil (0–10?cm) of a field trial with application of 0, 4.5, and 9?Mg biochar ha?1 using the benzene polycarboxylic acid method. To see if there is a temporal relation between BC input and WEBC formation, we took samples directly after biochar application and three years later. Bulk BC and also WEBC concentrations increased with increasing biochar application rates. In contrast, WEBC portions of bulk BC decreased with increasing amount of applied biochar. On average, we found between 7.56?±?2.50 and 12.56?±?1.34?mg WEBC per kg agricultural soil, making up 0.6–1.84% of bulk BC. Over time, no loss or accumulation of either component was observed. However, we found that the composition of WEBC differed from bulk BC; i.e. WEBC consisted of less condensed aromatic structures than bulk BC indicating that de-condensation processes are involved in the formation of leachable BC.Brenner, A.R., Fu, R.R., Evans, D.A.D., Smirnov, A.V., Trubko, R., Rose, I.R., 2020. Paleomagnetic evidence for modern-like plate motion velocities at 3.2 Ga. Science Advances 6, eaaz8670. mode and rates of tectonic processes and lithospheric growth during the Archean [4.0 to 2.5 billion years (Ga) ago] are subjects of considerable debate. Paleomagnetism may contribute to the discussion by quantifying past plate velocities. We report a paleomagnetic pole for the ~3180 million year (Ma) old Honeyeater Basalt of the East Pilbara Craton, Western Australia, supported by a positive fold test and micromagnetic imaging. Comparison of the 44°±15° Honeyeater Basalt paleolatitude with previously reported paleolatitudes requires that the average latitudinal drift rate of the East Pilbara was ≥2.5 cm/year during the ~170 Ma preceding 3180 Ma ago, a velocity comparable with those of modern plates. This result is the earliest unambiguous evidence yet uncovered for long-range lithospheric motion. Assuming this motion is due primarily to plate motion instead of true polar wander, the result is consistent with uniformitarian or episodic tectonic processes in place by 3.2 Ga ago.Bush, A.M., Wang, S.C., Payne, J.L., Heim, N.A., 2020. A framework for the integrated analysis of the magnitude, selectivity, and biotic effects of extinction and origination. Paleobiology 46, 1-22. taxonomic and ecologic composition of Earth’s biota has shifted dramatically through geologic time, with some clades going extinct while others diversified. Here, we derive a metric that quantifies the change in biotic composition due to extinction or origination and show that it equals the product of extinction/origination magnitude and selectivity (variation in magnitude among groups). We also define metrics that describe the extent to which a recovery (1) reinforced or reversed the effects of extinction on biotic composition and (2) changed composition in ways uncorrelated with the extinction. To demonstrate the approach, we analyzed an updated compilation of stratigraphic ranges of marine animal genera. We show that mass extinctions were not more selective than background intervals at the phylum level; rather, they tended to drive greater taxonomic change due to their higher magnitudes. Mass extinctions did not represent a separate class of events with respect to either strength of selectivity or effect. Similar observations apply to origination during recoveries from mass extinctions, and on average, extinction and origination were similarly selective and drove similar amounts of biotic change. Elevated origination during recoveries drove bursts of compositional change that varied considerably in effect. In some cases, origination partially reversed the effects of extinction, returning the biota toward the pre-extinction composition; in others, it reinforced the effects of the extinction, magnifying biotic change. Recoveries were as important as extinction events in shaping the marine biota, and their selectivity deserves systematic study alongside that of extinction.Bussmann, I., Fedorova, I., Juhls, B., Overduin, P.P., Winkel, M., 2020. Seasonal methane dynamics in three different Siberian water bodies. Biogeosciences Discussions 2020, 1-28. regions and their water bodies are being affected by the most rapid climate warming on Earth. Arctic lakes and small ponds are known to act as an important source of atmospheric methane. However, not much is known about other types of water bodies in permafrost regions, which include major rivers and coastal bays as a transition type between freshwater and marine environments. We monitored dissolved methane concentrations in three different water bodies (Lena River, Tiksi Bay and Lake Golzovoye, Siberia, Russia) over a period of two years. Sampling was carried out under ice cover (April) and in open water (July/August). The methane oxidation (MOX) rate in water and melted ice samples from the late winter of 2017 was also investigated. In the Lena River winter methane concentrations were a quarter of the summer concentrations (8 vs 31 nmol L?1) and mean winter MOX rate was low (0.023 nmol L?1 d?1). In contrast, Tiksi Bay winter methane concentrations were 10-times higher than in summer (103 vs 13 nmol L?1). Winter MOX rates showed a median of 0.305 nmol L?1 d?1. In Lake Golzovoye, median methane concentrations in winter were 40-times higher than in summer (1957 vs 49 nmol L?1). However, MOX was much higher in the lake (2.95 nmol L?1 d?1) than in either the river or bay. The temperature had a strong influence on the MOX, (Q10 = 2.72 ± 0.69) compared to temperate environments. In the ice cores a median methane concentration of 9 nM was observed, with no gradient between the ice surface and the bottom layer at the ice-water-interface. MOX in the (melted) ice cores was mostly below the detection limit. Comparing methane concentrations in the ice with the underlaying water column revealed 100 – 1000-times higher methane concentration in the water column. The winter situation seemed to favor a methane accumulation under ice, especially in the lake with a stagnant water body. While on the other hand, in the Lena River with its flowing water no methane accumulation under ice was observed. Methane oxidation rate was not able to counteract this winter time accumulation.Cadeau, P., Romero-Sarmiento, M.-F., Sissmann, O., Beaumont, V., 2020. On-line recovery system coupled to a Rock-Eval? device: An analytical methodology for characterization of liquid and solid samples. Organic Geochemistry 144, 104014. Rock-Eval? device has been widely used to identify the type and the thermal maturity of sedimentary organic matter, as well as for quantifying the total organic carbon content. Traditionally, it is a screening tool to estimate the petroleum generation potential of source rocks using standardized parameters. More recently, a new Rock-Eval? method (Shale Play?) was proposed for the investigation of the hydrocarbon content of liquid-rich tight rock samples. In this study, we describe a dual vacuum and on-line system that was developed to recover most compounds that are thermally released during a Rock-Eval? Shale Play? analysis. Thermally vaporized products are divided so that half is analyzed by the Rock-Eval? flame ionization detector (FID) while the other portion is cryogenically trapped in the on-line recovery system. The trapped products can then be transferred via a vacuum line system into a sample vial for subsequent molecular and/or isotopic composition analyses. The recovery vacuum line volumes were calibrated using known quantities of gas (CH4 and CO2). Sample transfer without isotopic fractionation was demonstrated for CO2 evolved from Rock-Eval? preparation of pure carbonate standards (siderite, magnesite and azurite). Recovery efficiencies were first measured on C8-C16 n-alkane standards and then on produced oil samples. Results indicate a high quantitative recovery and an accurate mass balance of most compounds released during the Shale Play? Sh0 thermovaporization step (100–200?°C). Thermally vaporized compounds released at higher temperatures Sh1 (200–350?°C) are recovered at lower efficiencies, but are still suitable for subsequent characterization. The coupled Rock-Eval? and recovery system could have applications beyond petroleum geochemistry.Cai, D., Wang, X., Chen, J., Li, X., 2020. Molecular characterization of organosulfates in highly polluted atmosphere using ultra-high-resolution mass spectrometry. Journal of Geophysical Research: Atmospheres 125, e2019JD032253. (OSs) have recently been observed to be a potentially important constituent of secondary organic aerosol (SOA); however, their molecular characterization in highly polluted atmospheres has not been probed in detail. This study thoroughly presents the characterization of OSs in polluted air and demonstrates their seasonal and diurnal variations, formation mechanisms, and contributions to organic aerosol. Atmospheric PM2.5 samples were collected from an urban Shanghai site across the winter and summer of 2017. OSs were characterized by ultra‐high‐performance liquid chromatography (UHPLC) coupled with Orbitrap mass spectrometry (MS). Based on exact mass formulae in conjunction with previous chamber studies, hundreds of sulfur‐containing compounds were tentatively identified as OSs. The number and abundance of OSs increased significantly during pollution episodes. The OSs in the clean aerosol samples were dominant in biogenic products, whereas the OSs in the polluted winter samples had distinctive anthropogenic characteristics. Aromatics and long‐chain alkanes from anthropogenic emissions might be their precursors. By using synthesized standards, the total concentrations of 14 quantified OSs ranged 21.6–161 ng m?3 in summer and 5.85–84.3 ng m?3 in winter, respectively. Among these OSs, glycolic acid sulfate was the most abundant species (1.13–122 ng m?3). Further analysis of their seasonal and diurnal variations suggests possible contributions from multiple formation mechanisms, including acid‐catalyzed and NO3‐initiated oxidation reactions. Our results highlight that increased anthropogenic pollutant emissions (e.g., NOx and SO2) can significantly enhance the SOA burden in biogenically influenced urban areas.Canfield, D.E., Knoll, A.H., Poulton, S.W., Narbonne, G.M., Dunning, G.R., 2020. Carbon isotopes in clastic rocks and the Neoproterozoic carbon cycle. American Journal of Science 320, 97-124. has been proposed that isotopically light inorganic carbon precipitated diagenetically in clastic sediments can explain the large carbon isotopic excursions recorded in Neoproterozoic carbonates. To date, however, the data needed to test this hypothesis have been limited. Here we report the analysis of ca. 540 clastic sedimentary rocks, including shales, siltstones, sandstones and tillites, that span the second half of the Neoproterozoic Era. A diagenetic carbon isotopic overprint does indeed occur in many of the samples; however, when we include our analyses in a carbon isotope mass balance model, they produce only a small effect on mass balance model results. Thus, clastic sedimentary rocks were not a major sink for 13C-depleted carbonate during the Neoproterozoic Era. These results do, however, produce a more accurate carbon mass balance, pointing to a high proportion of total organic carbon burial, compared to total carbon burial, during the late Tonian, Cryogenian, and late Ediacaran Periods. This result suggests a vigorous release of oxygen to the atmosphere. The clastic carbonate record also offers a chemostratigraphic tool. For example, we observe an isotope trend in clastic-hosted carbonates of the Isaac Formation, Windermere Supergroup, that strongly resembles the Shuram-Wonoka isotope anomaly, allowing us to place this previously undated section in a temporal context. We also find isotope trends in the fossiliferous and radiometrically well-dated sedimentary rocks of the Avalon Peninsula, Newfoundland, that may also reflect the Shuram-Wonoka anomaly. If correct, this constrains the timing of the Shuram event, suggesting that it began after 571 Ma and ended before 562 Ma, with the most extreme isotopic values lying well within those bounds. Cano, E.J., Sharp, Z.D., Shearer, C.K., 2020. Distinct oxygen isotope compositions of the Earth and Moon. Nature Geoscience 13, 270-274. virtually identical oxygen isotope compositions of the Earth and Moon revealed by Apollo return samples have been a challenging constraint for lunar formation models. For a giant impact scenario to explain this observation, either the precursors to the Earth and Moon had identical oxygen isotope values or extensive homogenization of the two bodies occurred following the impact event. Here we present high-precision oxygen isotope analyses of a range of lunar lithologies and show that the Earth and Moon in fact have distinctly different oxygen isotope compositions. Oxygen isotope values of lunar samples correlate with lithology, and we propose that the differences can be explained by mixing between isotopically light vapour, generated by the impact, and the outermost portion of the early lunar magma ocean. Our data suggest that samples derived from the deep lunar mantle, which are isotopically heavy compared to Earth, have isotopic compositions that are most representative of the proto-lunar impactor ‘Theia’. Our findings imply that the distinct oxygen isotope compositions of Theia and Earth were not completely homogenized by the Moon-forming impact, thus providing quantitative evidence that Theia could have formed farther from the Sun than did Earth.Cao, C., Zhang, M., Li, L., Wang, Y., Li, Z., Du, L., Holland, G., Zhou, Z., 2020. Tracing the sources and evolution processes of shale gas by coupling stable (C, H) and noble gas isotopic compositions: Cases from Weiyuan and Changning in Sichuan Basin, China. Journal of Natural Gas Science and Engineering 78, 103304. source and thermal evolution history of organic matter for the Longmaxi shale are still debated. This study analyzed the molecular and stable carbon isotopic compositions of hydrocarbons (CH4, C2H6, and C3H8) and CO2 as well as the stable hydrogen isotopic compositions of methane, ethane, and noble gases (He, Ne, Ar, Kr, and Xe). Shale gases in the WY and CN areas show an extremely-low-wetness with CH4 concentrations range from 93.41% to 99.01%. Non-hydrocarbon gases are mainly N2 (0.22%–2.81%) and CO2 (0.03%–1.35%). H2S have not been detected. Different δ13C1 and δ13C2 values in WY and CN shale gases (WY: ?37.3‰ to ?35.0‰ and ?40.3‰ to ?38.3‰, CN: ?29.8‰ to ?26.3‰ and ?35.3‰ to ?32.7‰) and various carbon isotope-composition distribution patterns (δ13C1>δ13C2<δ13C3 and δ13C1>δ13C2>δ13C3) of hydrocarbons indicate a complex evolution process. WY shale gases include more oil-cracking gas than CN shale gases, suggesting WY shale gases more like come from Type I-II organic matter. In shale gas systems, methane content and δ13C1 ratios vary with the degree of thermal evolution, so the origin of shale gas cannot be determined using carbon isotope data alone. The wide range of δ13CCO2 values (?8.9‰ to ?0.8‰) and N2/40Ar ratios (20.8–165.1) suggests multiple origins of the gases. Emeishan mantle plume provides the source of heat for some thermo-genic gas. Noble gas isotopic compositions (3He/4He: 0.001Ra to 0.019Ra) indicate air and crustal origins with no significant contribution from the mantle. 40Ar/36Ar ratios (1194.3–4604.5) are consistent with the age of Longmaxi strata calculated by accumulative effect of Ar isotope. The shale gas humidity, carbon isotope ratios, and the carbon isotope-composition distribution patterns may contain information indicating the shale gas sweet spot.Cao, Y., Zhang, B., Zhu, Z., Song, X., Cai, Q., Chen, B., Dong, G., Ye, X., 2020. Microbial eco-physiological strategies for salinity-mediated crude oil biodegradation. Science of The Total Environment 727, 138723. variability strongly affects the behaviors of oil degrading bacteria for spilled oil biodegradation in the marine environment. However, limited studies explored the strategies of microbes on salinity-mediated crude oil biodegradation. In this study, a halotolerant bio-emulsifier producer, Exiguobacterium sp. N41P, was examined as a model strain for Alaska North Slope (ANS) crude oil (0.5%, v/v) biodegradation. Results indicated that Exiguobacterium sp. N41P could tolerant a wide range of salinity (0–120?g/L NaCl) and achieve the highest degradation efficiency under the salinity of 15?g/L NaCl due to the highest biofilm formation ability. Moreover, increased salinity induced decreased cell surface hydrophobicity and a migration of microbial growth from oil phase to aqueous phase, leading to limited bio-emulsifier productivity and depressed degradation of insoluble long-chain n-alkanes while enhancing the degradation of relative soluble naphthalene. Research findings illustrated the microbial eco-physiological mechanism for spilled oil biodegradation under diverse salinities and advanced the understanding of sophisticated marine crude oil biodegradation process.Capriolo, M., Marzoli, A., Aradi, L.E., Callegaro, S., Dal Corso, J., Newton, R.J., Mills, B.J.W., Wignall, P.B., Bartoli, O., Baker, D.R., Youbi, N., Remusat, L., Spiess, R., Szabó, C., 2020. Deep CO2 in the end-Triassic Central Atlantic Magmatic Province. Nature Communications 11, 1670. Igneous Province eruptions coincide with many major Phanerozoic mass extinctions, suggesting a cause-effect relationship where volcanic degassing triggers global climatic changes. In order to fully understand this relationship, it is necessary to constrain the quantity and type of degassed magmatic volatiles, and to determine the depth of their source and the timing of eruption. Here we present direct evidence of abundant CO2 in basaltic rocks from the end-Triassic Central Atlantic Magmatic Province (CAMP), through investigation of gas exsolution bubbles preserved by melt inclusions. Our results indicate abundance of CO2 and a mantle and/or lower-middle crustal origin for at least part of the degassed carbon. The presence of deep carbon is a key control on the emplacement mode of CAMP magmas, favouring rapid eruption pulses (a few centuries each). Our estimates suggest that the amount of CO2 that each CAMP magmatic pulse injected into the end-Triassic atmosphere is comparable to the amount of anthropogenic emissions projected for the 21st century. Such large volumes of volcanic CO2 likely contributed to end-Triassic global warming and ocean acidification.Carbonne, J.M., 2020. Fe isotope composition of Archean sulfides do not record progressive oxygenation of the ocean. Geology 48, 415-416. the history of this continuously evolving planet, the Great Oxygenation Event (GOE), which occurred at ca. 2.3 Ga (Bekker et al., 2004; Holland, 2006) was a critical environmental change. This event was first recognized by the disappearance of detrital uraninite, pyrite, and siderite, from the siliciclastic record, as well as by shales that do not contain appreciable amounts of redox-sensitive elements and paleosols that are not oxidized before ca. 2.3 Ga (Holland, 2006). These observations are most consistent with a change from an anoxic to a moderately oxygenated atmosphere during the GOE. The discovery of mass independent fractionation (S-MIF) in sulfur isotopes brought new constraints on the emergence of oxygen and on the atmospheric composition (Farquhar et al., 2000). Indeed, Archean sulfate and sulfides from sediments older than 2.45 Ga display S-MIF up to 10 ‰ (see Ono, 2017, for a review), while sulfates and sulfides from younger sedimentary rocks have close to 0‰ S-MIF. The consensual mechanism for producing the S-MIF in sulfur isotopes is photochemical dissociation of volcanic SO2 in an anoxic atmosphere (Farquhar et al., 2000; Thiemens et Lin, 2019) with O2 levels below 10?5 × the present atmospheric level (PAL), though alternative views exist (see Oduro et al., 2011). In the past decades, numerous studies have documented in detail the timing of, extent of, and processes responsible for the GOE (Claire et al., 2006; Halevy, 2013; Zahnle et al. 2013; Lyons et al., 2014; Luo et al., 2016). Studies based on stable isotope compositions of redox elements (like S, Mo, Fe, Th, and Cr) have suggested the existence of oxygenated oases before 2.3 Ga (see Anbar et al., 2007; Partin et al., 2013; Izon et al., 2015; Eickmann et al., 2018; Ostrander et al., 2019; among others).Complementary to the sulfur isotope record, the Fe stable isotope systematics was used to highlight a secular evolution both in iron oxides and sulfides. Pre-GOE pyrites display negative Fe isotope compositions down to –3.5‰, while post-GOE pyrites have more homogeneous δ56Fe values. This Fe isotope evolution has been interpreted as reflecting progressive oxidation of the ocean before the GOE, with partial removal of iron oxides decreasing the δ56Fe values of Fe2+ by distillation (Rouxel et al., 2005), but also reflecting significant microbial dissimilatory Fe3+ reduction (DIR) metabolic activity (Severmann et al., 2008). Experimental studies have proposed that Fe isotope compositions in pyrite are controlled mostly by kinetic isotope effects (KIE; Guilbaud et al., 2011; Rolison et al., 2018; Mansor and Fantle, 2019) and thus that pyrite can record fractionation during limited pyritization. Therefore, the reliability of pyrite as a true proxy of the Fe(II) isotope composition of the parent fluid has been recently challenged (Busigny et al., 2014; Rolison et al., 2018; Frierdich et al., 2019). Consequently, the Fe secular isotope evolution through the Archean-Proterozoic transition needs to be investigated in detail.In this issue of Geology, Heard and Dauphas (2020, p. 358) have gracefully reexamined what controlled Fe isotope composition in the oxic and sulfidic sinks of the ocean throughout the GOE. By compiling published bulk sedimentary Fe isotope records from both iron oxides and sulfides, they have tested two hypotheses: either (1) pyrite Fe isotope compositions reflect partial oxidation of the ocean, or (2) they are due to partial pyritization with a large KIE. The absence of positive correlations between δ56Fe values of iron oxides and pyrites led the authors to rule out the first hypothesis. The presence of a positive correlation between δ56Fe and δ34S in pyrite is within the framework of the second hypothesis. In a low-sulfate ocean, characteristic of the Archean (Crowe et al., 2014), pyritization should have been limited, and thus a large KIE is anticipated. Therefore, based on the ambivalent correlation between δ56Fe and δ34S, and also based on the recognition of Rayleigh distillation distribution in Archean pyrites at bulk and at microscale, Heard and Dauphas thus argue that the Fe isotope compositions in pyrite are controlled by the sulfur availability, rather than reflecting partial oxidation of the ocean. This conclusion is not entirely new and has already been suggested by several authors; however, this is the first study that takes advantage of the entire literature on Fe isotope compositions of Archean and Proterozoic sediments published to date.This elegant study highlights the complexity of Fe isotope records in pyrite through time, that need to be further investigated. In fact, the influence of DIR on pyrite Fe isotope compositions is still not defined precisely and cannot be ruled out from this study. Future studies should also focus on post-GOE iron oxides and sulfides, as only one iron oxide formation has been thus far studied for Fe isotope systematics. Further experimental studies and microscale analyses of sedimentary pyrites will offer quantitative data that will help to decipher what exactly controls Fe isotope compositions during pyrite formation. Even if both Fe and S pyrite isotope records have many subtleties, Heard and Dauphas have made a useful re-interpretation of the Fe secular isotope evolution, and have provided a geochemical framework to better understand the sedimentary pyrite record.Casanova, E., Knowles, T.D.J., Bayliss, A., Dunne, J., Barański, M.Z., Denaire, A., Lefranc, P., di Lernia, S., Roffet-Salque, M., Smyth, J., Barclay, A., Gillard, T., Cla?en, E., Coles, B., Ilett, M., Jeunesse, C., Krueger, M., Marciniak, A., Minnitt, S., Rotunno, R., van de Velde, P., van Wijk, I., Cotton, J., Daykin, A., Evershed, R.P., 2020. Accurate compound-specific 14C dating of archaeological pottery vessels. Nature 580, 506-510. is one of the most commonly recovered artefacts from archaeological sites. Despite more than a century of relative dating based on typology and seriation, accurate dating of pottery using the radiocarbon dating method has proven extremely challenging owing to the limited survival of organic temper and unreliability of visible residues. Here we report a method to directly date archaeological pottery based on accelerator mass spectrometry analysis of 14C in absorbed food residues using palmitic (C16:0) and stearic (C18:0) fatty acids purified by preparative gas chromatography. We present accurate compound-specific radiocarbon determinations of lipids extracted from pottery vessels, which were rigorously evaluated by comparison with dendrochronological dates and inclusion in site and regional chronologies that contained previously determined radiocarbon dates on other materials. Notably, the compound-specific dates from each of the C16:0 and C18:0 fatty acids in pottery vessels provide an internal quality control of the results and are entirely compatible with dates for other commonly dated materials. Accurate radiocarbon dating of pottery vessels can reveal: (1) the period of use of pottery; (2) the antiquity of organic residues, including when specific foodstuffs were exploited; (3) the chronology of sites in the absence of traditionally datable materials; and (4) direct verification of pottery typochronologies. Here we used the method to date the exploitation of dairy and carcass products in Neolithic vessels from Britain, Anatolia, central and western Europe, and Saharan Africa.Castilla, C., Rüger, C.P., Marcotte, S., Lavanant, H., Afonso, C., 2020. Direct inlet probe atmospheric pressure photo and chemical ionization coupled to ultrahigh resolution mass spectrometry for the description of lignocellulosic biomass. Journal of the American Society for Mass Spectrometry 31, 822-831. biomass, in particular wood, is a complex mixture containing cellulose, hemicellulose, lignin, and other trace compounds. Chemical analysis of these biomasses, especially lignin components, is a challenge. Lignin is a highly reticulated polymer that is poorly soluble and usually requires chemical, enzymatic, or thermal degradation for its analysis. Here, we studied the thermal degradation of lignocellulosic biomass using a direct insertion probe (DIP). The DIP was used with two ionization sources: atmospheric pressure chemical ionization (APCI) and atmospheric pressure photoionization (APPI) coupled to ultrahigh-resolution mass spectrometry. Beech lignocellulosic biomass samples were used to develop the DIP-APCI/APPI methodology. Two other wood species (maple and oak) were analyzed after optimization of DIP parameters. The two ionization sources were compared at first and showed different responses toward beech samples, according to the source specificity. APPI was more specific to lignin degradation compounds, whereas APCI covered a larger variety of oxygenated compounds, e.g., fatty acids and polyphenolics compounds, in addition to lignin degradation products. The study of the thermodesorption profile gave information on the different steps of lignocellulosic biomass pyrolysis. The comparison of the three feed sample types (oak, maple, and beech), using principal component analysis (PCA) with DIP-APCI experiments, showed molecular level differences between beech wood pellets and the two other wood species (maple and oak).Chai, Z., Chen, Z., Liu, H., Cao, Z., Cheng, B., Wu, Z., Qu, J., 2020. Light hydrocarbons and diamondoids of light oils in deep reservoirs of Shuntuoguole Low Uplift, Tarim Basin: Implication for the evaluation on thermal maturity, secondary alteration and source characteristics. Marine and Petroleum Geology 117, 104388. Shuntuoguole Low Uplift in Tarim Basin is particular because it provides insights into geochemistry of light oils at ultra-deep Ordovician oil reservoirs (7200–8200 m). The light hydrocarbons and diamondoids of 16 oil samples from Shunbei No. I Fault Zone (F1) and V Fault Zone (F5) were analyzed to investigate their thermal maturity, source characteristics and secondary alteration. The oils show high similarity in the characteristics of light hydrocarbons and diamondoids. The light hydrocarbons are characterized by high contents of alkanes and low contents of cycloalkanes and aromatics, and the diamondoids show a domination of adamantanes and their alkylated isomers compared diamantanes. Thermal maturity indicators derived from diamondoids and C5–C7 light hydrocarbons indicate that the oils are highly mature, and the corresponding equivalent vitrinite reflectance (Rc) determined by light hydrocarbons and methyldiadamantane index are in the ranges of 1.2%–1.5%. Signatures of biodegradation and thermochemical sulfate reduction were not observed in the oils. The geochemical information from the light hydrocarbons and distribution patterns of molar concentration of n-alkanes indicate that the oils from F1 experienced noticeable evaporative fractionation, and the oils from F5 did not. This was supposed to be the primarily reason for the physical difference between oils from the both fault zones. The parameters derived from the light hydrocarbons and diamondoids indicate the oils are from same source rocks, which are associated with marine materials with type II kerogen, such as algae and bacteria, and both of Cambrian–Lower Ordovician (?-O1) and Middle–Upper Ordovician (O2–3) source rocks in the deep Lower Palaeozoic strata contributed to the oils.Chasib, K.F., 2020. An investigation on the feasibility of using mixed reversible ionic liquids for extraction of kerogen from oil shale. Egyptian Journal of Petroleum 29, 53-57. of the separation issue usually accompanying with traditional ionic liquids can solve with Reversible ionic liquids. It can be forth and reversed back between ionic and molecular forms empowering superficial separations by means of considerable changes in situ property. This leads to actually sustainable processes. A comprehension of the systems phase behavior gives frameworks into the ability of separation.To our knowledge, the experimental information available in the literature for mixtures containing the pair Kerogen-Reversible Ionic Liquids (RevIL) is limited. Thus the objective of the current investigation is to produce data for Kerogen with different Reversible Ionic Liquids RevIL solvents to aid the extraction efficiency.The samples of Oil Shale collected from real Iraqi sedimentary rock deposits. Four Reversible Ionic Liquids solvents 3-(triethoxysilyl)-propylammonium 3-(triethoxysilyl)-propyl carbamate (TESAC), (3-(tripropylsilyl)-propylammonium 3-(tripropylsilyl)-propyl carbamate (TPSAC), 3-(trimethoxysilyl)-propylammonium 3-(trimethoxysilyl)-propyl carbamate (TMSAC), 3-(triethylsilyl)-propylammonium 3-(triethylsilyl)-propyl carbamate (TEtSAC)) are derived from carbon dioxide which reacts reversibly with silylated amine molecular liquids to produce ionic liquids.The efficiency of four Reversible Ionic Liquids (TEtSAC, TMSAC, TPSAC, and TESAC) and for mixed Reversible ionic liquid (Binary mixtures) as a selective solvent in the kerogen extraction from oil shale was investigated.The extraction efficiency was found to be more dependent on the basicity strength of hydrogen bond of the RevIL. It was found that higher extraction efficiencies are accompanied with higher hydrogen bond basicity.Four single RevILs and three binary mixtures (RevIL) to extract the Kerogen from oil shale is used. The study shows that the highest Kerogen extraction efficiency of 90.2% and 97.9% respectively, can be achieved by TESAC and (TESAC?+?TMSAC) respectively. One mixed binary solvent (TESAC?+?TMSAC) has the highest distribution coefficient, extraction efficiency and selectivity and greatest variation between its density and boiling point and those of Kerogen is selected. Therefore it can be considered as an excellent extracting solvent for Kerogen from oil shale.Chen, C.-F., Ju, Y.-R., Lim, Y.C., Hsu, N.-H., Lu, K.-T., Hsieh, S.-L., Dong, C.-D., Chen, C.-W., 2020. Microplastics and their affiliated PAHs in the sea surface connected to the southwest coast of Taiwan. Chemosphere 254, 126818. by microplastics (MPs) and the associated organic pollutants has caused potential threats to the ecological environment of global waters. In this study, MPs were sampled by trawling from the surface waters of the estuary, fishing port entrance and harbor entrance areas connected to the southwestern coast of Taiwan. Moreover, the abundance, morphological characteristics, composition, and associated polycyclic aromatic hydrocarbons (PAHs) of MPs were analyzed. The abundance of MPs was 0.36 ± 0.21 items/m3, which was 6.4 ± 10.7% of the abundance of zooplanktons. The average abundance of MPs was the highest in the estuary area, indicating that river transport was the primary way for MPs to enter the ocean. The most dominant MPs were small (0.33–2 mm; 78.8 ± 8.1%), colored (60.0 ± 12.8%), fragments (66.1 ± 10.6%), comprising PE (52.6 ± 7.6%), and PP (38.7 ± 9.4%). The decomposition of various plastic products and disposable plastic packaging may be the most significant source. The total concentration of PAHs in MPs ranged from 104 to 3595 ng/g dw, with an average of 818 ± 874 ng/g dw. The diagnostic ratios and the results of principal component analysis (PCA) and multiple linear regression of the absolute principal component scores (MLR-APCS) indicated that the PAHs were mainly contributed from sources related to petrogenic (71.4%) and vehicles (28.6%). Most likely due to MPs on the sea surface coming into contact with floating oil spills from ships or floating tar particles.Chen, C.-F., Ju, Y.-R., Su, Y.-C., Lim, Y.C., Kao, C.-M., Chen, C.-W., Dong, C.-D., 2020. Distribution, sources, and behavior of PAHs in estuarine water systems exemplified by Salt River, Taiwan. Marine Pollution Bulletin 154, 111029., suspended particulate matter (SPM), and sediment samples were collected from Salt River in Taiwan and analyzed the concentrations of 16 types of polycyclic aromatic hydrocarbons (PAHs). The analysis results were used to examine the distribution, source, partition behavior, and potential ecological risks of PAHs in the estuarine water systems. The mean concentration of total PAHs in water, SPM, and sediment samples was 0.485–10.2 μg/L, 26.7–169 mg/kg dw, and 0.343–29.4 mg/kg dw, respectively. The highest concentration was found at the river mouth and decreased toward the river and sea with the tide. The distribution of the diagnostic ratios of PAHs showed that the combustion of coal and petroleum products are the main sources of PAHs in Salt River. The in site organic carbon normalized partition coefficients for SPM-water (K'oc(SPM-W)) and sediment-water (K'oc(Sed-W)) were 2.8–4.5 and 4.6–6.0 (log units), respectively, increasing with the number of rings in PAHs. The values log K'oc(Sed-W) and log K'oc(SPM-W) showed a significant linear correlation with their octanol-water partition coefficients (p < 0.01), and their slopes were 0.427 and 0.316, respectively. The fugacity fraction was used to evaluate the exchange of PAHs in water-SPM-sediment systems. Results showed that in SPM, 2–4-ring PAHs tend to be released into water, whereas 5–6-ring PAHs in water tend to be adsorbed onto SPM. The exchange of PAHs between water and sediment occurs in the direction of adsorption onto sediment from water. The assessment of the mean risk quotient, total toxicity equivalence, and mean effect range-median quotient of PAHs showed that the PAHs in the water and SPM of Salt River may have moderate to high ecological risk. In sediment, PAHs in the lower reaches and estuary may pose moderate to high ecological risk, whereas PAHs in the middle and upper reaches show low to moderate ecological risk.Chen, J., Dietrich, F., Maazallahi, H., Forstmaier, A., Winkler, D., Hofmann, M.E.G., Denier van der Gon, H., R?ckmann, T., 2020. Methane emissions from the Munich Oktoberfest. Atmospheric Chemistry and Physics 20, 3683-3696. study presents the first investigation of the methane (CH4) emissions of a large festival. Munich Oktoberfest, the world's largest folk festival, is a potential source of CH4 as a large amount of natural gas for cooking and heating is used.In 2018 we measured the CH4 emissions of Oktoberfest using in situ measurements combined with a Gaussian plume dispersion model. Measurements were taken while walking and biking around the perimeter of the Oktoberfest premises (Theresienwiese) at different times of the day, during the week and at the weekend. The measurements showed enhancements of up to 100?ppb compared to background values and measurements after Oktoberfest. The average emission flux of Oktoberfest is determined as (6.7±0.6)??g?(m2?s)?1. Additional analyses, including the daily emission cycle and comparisons between emissions and the number of visitors, suggest that CH4 emissions of Oktoberfest are not due solely to the human biogenic emissions. Instead, fossil fuel CH4 emissions, such as incomplete combustion or loss in the gas appliances, appear to be the major contributors to Oktoberfest emissions.Our results can help to develop CH4 reduction policies and measures to reduce emissions at festivals and other major events in cities. Furthermore, events with a limited duration have not yet been included in the state-of-the-art emission inventories, such as TNO-MACC, EDGAR or IER. Our investigations show that these emissions are not negligible. Therefore, these events should be included in future emission inventories.Chen, X., Qu, X., Xu, S., Wang, W., Li, S., He, H., Liu, Y., 2020. Dissolution pores in shale and their influence on reservoir quality in Damintun Depression, Bohai Bay Basin, East China: Insights from SEM images, N2 adsorption and fluid-rock interaction experiments. Marine and Petroleum Geology 117, 104394. pore characterization is crucial for understanding the mechanism of shale hydrocarbon accumulation and its effective exploitation. X-ray diffraction (XRD), optical microscopy, scanning electron microscopy (SEM), pore extraction, nitrogen (N2) adsorption, and fluid-rock interaction experiments were used to study the shale pore structure of the fourth member of the Paleogene Shahejie Formation in the Damintun Depression, East China. The Damintun shale included three types of pores: organic matter pores, mineral matrix pores, and microfractures. The dissolution pores were mainly developed between and inside the matrix minerals, such as calcite, dolomite, and feldspar. The average shale visible dissolution porosity determined using SEM was 1.12%. N2 adsorption analysis revealed that the less than 20?nm pores were the main reservoir space in the Damintun shale. Fluid-rock interaction experiments indicated that the degrees of dissolution of the calcite and dolomite were similar and stronger than those of the K-feldspar and plagioclase. The shale with a high content of carbonate minerals (calcite and dolomite) exhibited more intense dissolution. The degree of dissolution pores development was positively correlated with total organic carbon (TOC) and carbonate mineral (calcite and dolomite) contents. The average contribution of the dissolution porosity to the total porosity of the shale was 18.20%. However, the contribution of the dissolution pores increased with increasing pore size only when the average pore diameter was larger than 12?nm. This may be due to the fact that small pores (diameter <12?nm) are more easily to be filled by re-precipitated minerals. The total porosity and the contribution of the dissolution pores were positively correlated with the dissolution porosity, revealing that dissolution pores are an important factor affecting the quality of shale reservoirs.Chen, Y., Jha, N.K., Al-Bayati, D., Lebedev, M., Sarmadivaleh, M., Iglauer, S., Saeedi, A., Xie, Q., 2020. Geochemical controls on wettability alteration at pore-scale during low salinity water flooding in sandstone using X-ray micro computed tomography. Fuel 271, 117675. performed a pore-scale multiphase flow experiment on a sandstone core sample. We imaged the core sample at initial oil saturation, residual oil saturations after high salinity and low salinity water flooding. Moreover, we examined fluid occupancy maps and water cluster size distribution at pore-scale before and after low salinity waterflooding. Furthermore, we performed a geochemical study to relate physicochemical process at sub-pore scale to account for in-situ wettability alteration at pore-scale.Micro-CT imaging shows that low salinity waterfloodng yielded 5% of residual oil saturation reduction after high salinity water flooding. Fluid occupancy maps within pore network show water film propagation at pore surface during low salinity water flooding, suggesting the oil film detachment from pore surfaces due to in-situ wettability alteration. Micro-CT imaging analysis also shows that the large size water cluster (greater than 107 ?m3) occupies 87.7% of water volume after high salinity water flooding, whereas the same size water cluster occupies 89.6% pore volume after low salinity water flooding, implying that water clusters coalesce into each other to transport in pore network during low salinity water flooding in line with fluid occupancy maps. Geochemical modelling predicts a pH increase (from 7 to 8.9) during low salinity water flooding largely due to ankerite and albite dissolution. This study sheds light on the significance of geochemical controls over wettability alteration at pore-scale through water film propagation.Cheng, F., Bayat, H., Jena, U., Brewer, C.E., 2020. Impact of feedstock composition on pyrolysis of low-cost, protein- and lignin-rich biomass: A review. Journal of Analytical and Applied Pyrolysis 147, 104780. is a major component of the global renewable energy market due to the low requirement for energy infrastructure modification and the high bio-energy productivity. Bio-ethanol production from sugar-rich biomass, biodiesel production from lipid-rich biomass, and biogas production from volatile-matter-dense feedstock have been commercialized. A substantial fraction of biomass waste, however, is still discarded due to high processing costs and low end-product values. This fraction includes agricultural wastes, dedicated plants, spent grains, de-oiled seed cakes, forestry wastes, food wastes, municipal wastes, and digestated residues. Such wastes generally contain fewer digestible compounds (e.g. fatty acids and sugars), and more proteins and recalcitrant lignin, which require more severe reaction conditions to extract valuable compounds. Pyrolysis is a potential inexpensive extraction option for these compounds with the needed reaction severity, easy operation, and high compatibility with diverse feedstocks. Here, pyrolysis reactions of protein- and lignin-rich biomass wastes are compared in terms of feedstock composition, degradation mechanism, and yield and quality of bio-oils. Overall, agricultural wastes, dedicated plants, seed cakes, digestates, and municipal wastes are recommended for pyrolysis in terms of higher yields and higher quality of bio-oils. Denitrogenation upgrading strategies can further improve the potential of the produced bio-oils.Cheng, K., Elrick, M., Romaniello, S.J., 2020. Early Mississippian ocean anoxia triggered organic carbon burial and late Paleozoic cooling: Evidence from uranium isotopes recorded in marine limestone. Geology 48, 363-367. Early Mississippian (Tournaisian) positive δ13C excursion (mid-Tournaisian carbon isotope excursion [TICE]) was one of the largest in the Phanerozoic, and the organic carbon (OC) burial associated with its development is hypothesized to have enhanced late Paleozoic cooling and glaciation. We tested the hypothesis that expanded ocean anoxia drove widespread OC burial using uranium isotopes (δ238U) of Lower Mississippian marine limestone as a global seawater redox proxy. The δ238U trends record a large Tournaisian negative excursion lasting ～1 m.y. The lack of covariation between δ238U values and facies changes and proxies for local depositional and diagenetic influences suggests that the δ238U trends represent a global seawater redox signal. The negative δ238U excursion is coincident with the first TICE positive excursion, supporting the hypothesis that an expanded ocean anoxic event controlled OC burial. These results provide the first evidence from a global seawater redox proxy that an ocean anoxic event drove Tournaisian OC burial and controlled Early Mississippian cooling and glaciation. Uranium and carbon modeling results indicate that (1) there was an ～6× increase in euxinic seafloor area, (2) OC burial was initially driven by expanded euxinia followed by expanded anoxic/suboxic conditions, and (3) OC burial mass was ～4–17× larger than that sequestered during other major ocean anoxic events.Cheng, X., Hou, D., Zhou, X., Liu, J., Diao, H., Jiang, Y., Yu, Z., 2020. Organic geochemistry and kinetics for natural gas generation from mudstone and coal in the Xihu Sag, East China Sea Shelf Basin, China. Marine and Petroleum Geology 118, 104405. comparative study on organic geochemistry and kinetics was performed on two representative coal measure mudstone and coal samples of the Eocene Pinghu Formation in the Xihu Sag, East China Sea Shelf Basin, China. Gas chromatography–mass spectrometry analysis of the aliphatic fractions of the source rock extracts was performed to characterize the maturity, depositional conditions, and source materials in the samples. The kerogens isolated from the mudstone and coal were pyrolyzed in a closed-system at two heating rates to determine the kinetics for natural gas generation, and the results were extrapolated to geological conditions. Biomarker assemblages show that the mudstone (type III kerogen) and coal (type II/III kerogen) contain predominantly terrigenous source materials with the effect of microbial reworking, and were deposited under oxic conditions within an unstratified water column. The mudstone has slightly more algal material input and less oxic conditions during deposition than the coal. The rocks are at the early-mature stage but the coal is slightly more mature than the mudstone. The activation energies for natural gas generation from the mudstone and coal distribute mainly in the range of 47–62 kcal/mol and 50–69 kcal/mol with a frequency factor of 2.0 × 1011 s?1 and 1.0 × 1013 s?1, respectively. The lower activation energies for the mudstone than the coal suggests an earlier onset of natural generation. Assuming a constant burial heating rate of 3 °C/Ma for the calculated activation energy distributions, the calculated temperature for a given transformation ratio can differ by > 60 °C, indicating varying kinetic stability due to different kerogen composition and structure. This significant and unexpected difference suggests that more attentions should be paid to the kinetic heterogeneity of coal bearing source rocks, and we must be particularly cautious about selecting appropriate kinetic models in petroleum system modeling.Cho, I.J., Choi, K.R., Lee, S.Y., 2020. Microbial production of fatty acids and derivative chemicals. Current Opinion in Biotechnology 65, 129-141. production of fatty acids and derivatives from non-edible biomass has attracted much attention as an alternative to their production from plant oils and animal fats. Fatty acids and some of their derivatives are ubiquitous metabolites synthesized for membrane biosynthesis and other metabolic purposes in microorganisms. These compounds, however, are rarely produced beyond cellular demands, frequently resulting in low titers even after metabolic engineering. Recently, more advanced metabolic engineering strategies including systems metabolic engineering allowed improved production of fatty acids and their derivatives by employing non-oleaginous and oleaginous microorganisms. Here, we review metabolic engineering strategies developed for the production of fatty acids and derivative chemicals by non-oleaginous and oleaginous microorganisms in recent years.Choi, K.R., Jiao, S., Lee, S.Y., 2020. Metabolic engineering strategies toward production of biofuels. Current Opinion in Chemical Biology 59, 1-14. of climate change and air pollution around the world have emphasized the necessity of replacing fossil fuels with clean and sustainable energy. Metabolic engineering has provided strategies to engineer diverse organisms for the production of biofuels from renewable carbon sources. Although some of the processes are commercialized, there has been continued effort to produce advanced biofuels with higher efficiencies. In this article, metabolic engineering strategies recently exploited to enhance biofuel production and facilitate utilization of non-edible low-value carbon sources are reviewed. The strategies include engineering enzymes, exploiting new pathways, and systematically optimizing metabolism and fermentation processes, among others. In addition, metabolic and bioprocess engineering strategies to achieve competitiveness of current biofuel production systems compared with fossil fuels are discussed.Chu, H., Gao, G.-F., Ma, Y., Fan, K., Delgado-Baquerizo, M., 2020. Soil microbial biogeography in a changing world: Recent advances and future perspectives. mSystems 5, e00803-19. microbial communities are fundamental to maintaining key soil processes associated with litter decomposition, nutrient cycling, and plant productivity and are thus integral to human well-being. Recent technological advances have exponentially increased our knowledge concerning the global ecological distributions of microbial communities across space and time and have provided evidence for their contribution to ecosystem functions. However, major knowledge gaps in soil biogeography remain to be addressed over the coming years as technology and research questions continue to evolve. In this minireview, we state recent advances and future directions in the study of soil microbial biogeography and discuss the need for a clearer concept of microbial species, projections of soil microbial distributions toward future global change scenarios, and the importance of embracing culture and isolation approaches to determine microbial functional profiles. This knowledge will be critical to better predict ecosystem functions in a changing world.This minireview went through the journal&#039;s normal peer review process. DayTwo sponsored the minireview and its associated video but had no editorial input on the content.Clark, D.E., Oelkers, E.H., Gunnarsson, I., Sigfússon, B., Sn?bj?rnsdóttir, S.?., Aradóttir, E.S., Gíslason, S.R., 2020. CarbFix2: CO2 and H2S mineralization during 3.5?years of continuous injection into basaltic rocks at more than 250?°C. Geochimica et Cosmochimica Acta 279, 45-66. CarbFix method was upscaled at the Hellishei?i geothermal power plant to inject and mineralize the plant’s CO2 and H2S emissions in June 2014. This approach first captures the gases by their dissolution in water, and the resulting gas-charged water is injected into subsurface basalts. The dissolved CO2 and H2S then react with the basaltic rocks liberating divalent cations, Ca2+, Mg2+, and Fe2+, increasing the fluid pH, and precipitating stable carbonate and sulfide minerals. By the end of 2017, 23,200 metric tons of CO2 and 11,800 metric tons of H2S had been injected to a depth of 750?m into fractured, hydrothermally altered basalts at >250?°C. The in situ fluid composition, as well as saturation indices and predominance diagrams of relevant secondary minerals at the injection and monitoring wells, indicate that sulfide precipitation is not limited by the availability of Fe or by the consumption of Fe by other secondary minerals; Ca release from the reservoir rocks to the fluid phase, however, is potentially the limiting factor for calcite precipitation, although dolomite and thus aqueous Mg may also play a role in the mineralization of the injected carbon.During the first phase of the CarbFix2 injection (June 2014 to July 2016) over 50% of injected carbon and 76% of sulfur mineralized within four to nine months, but these percentages increased four months after the amount of injected gas was doubled during the second phase of CarbFix2 (July 2016 – December 2017) at over 60% of carbon and over 85% of sulfur. The doubling of the gas injection rate decreased the pH of the injection water liberating more cations for gas mineralization. Notably, the injectivity of the injection well has remained stable throughout the study period confirming that the host rock permeability has been essentially unaffected by 3.5?years of mineralization reactions. Lastly, although the mineralization reactions are accelerated by the high temperatures (>250?°C), this is the upper temperature limit for carbon storage via the mineral carbonation of basalts as higher temperatures leads to potential decarbonation reactions.Close, R.A., Benson, R.B.J., Saupe, E.E., Clapham, M.E., Butler, R.J., 2020. The spatial structure of Phanerozoic marine animal diversity. Science 368, 420-424.: The global fossil record of marine animals has fueled long-standing debates about diversity change through time and the drivers of this change. However, the fossil record is not truly global. It varies considerably in geographic scope and in the sampling of environments among intervals of geological time. We account for this variability using a spatially explicit approach to quantify regional-scale diversity through the Phanerozoic. Among-region variation in diversity is comparable to variation through time, and much of this is explained by environmental factors, particularly the extent of reefs. By contrast, influential hypotheses of diversity change through time, including sustained long-term increases, have little explanatory power. Modeling the spatial structure of the fossil record transforms interpretations of Phanerozoic diversity patterns and their macroevolutionary explanations. This necessitates a refocus of deep-time diversification studies.Editor's summary: Across time, but also across space. Fossils, especially those from marine systems, have long been used to estimate changes in patterns of diversity over time. However, fossils are patchy in their occurrence, so such temporal estimates generally have not included variations due to space. Such a singular examination has the potential to simplify, or even misrepresent, patterns. Close et al. used a spatially explicit approach to measure diversity changes in marine fossils across time and space. They found that, like modern systems, diversity varies considerably across space, with reefs increasing diversity levels. Accounting for this spatial-environmental variation will shed new light on the study of diversity over time.Cole, D.B., Mills, D.B., Erwin, D.H., Sperling, E.A., Porter, S.M., Reinhard, C.T., Planavsky, N.J., 2020. On the co-evolution of surface oxygen levels and animals. Geobiology 18, 260-281. topics in geobiology have been as extensively debated as the role of Earth's oxygenation in controlling when and why animals emerged and diversified. All currently described animals require oxygen for at least a portion of their life cycle. Therefore, the transition to an oxygenated planet was a prerequisite for the emergence of animals. Yet, our understanding of Earth's oxygenation and the environmental requirements of animal habitability and ecological success is currently limited; estimates for the timing of the appearance of environments sufficiently oxygenated to support ecologically stable populations of animals span a wide range, from billions of years to only a few million years before animals appear in the fossil record. In this light, the extent to which oxygen played an important role in controlling when animals appeared remains a topic of debate. When animals originated and when they diversified are separate questions, meaning either one or both of these phenomena could have been decoupled from oxygenation. Here, we present views from across this interpretive spectrum?in a point?counterpoint format?regarding crucial aspects of the potential links between animals and surface oxygen levels. We highlight areas where the standard discourse on this topic requires a change of course and note that several traditional arguments in this ?life versus environment? debate are poorly founded. We also identify a clear need for basic research across a range of fields to disentangle the relationships between oxygen availability and emergence and diversification of animal life.Colman, D.R., Lindsay, M.R., Amenabar, M.J., Fernandes-Martins, M.C., Roden, E.R., Boyd, E.S., 2020. Phylogenomic analysis of novel Diaforarchaea is consistent with sulfite but not sulfate reduction in volcanic environments on early Earth. The ISME Journal 14, 1316-1331. origin(s) of dissimilatory sulfate and/or (bi)sulfite reducing organisms (SRO) remains enigmatic despite their importance in global carbon and sulfur cycling since at least 3.4?Ga. Here, we describe novel, deep-branching archaeal SRO populations distantly related to other Diaforarchaea from two moderately acidic thermal springs. Dissimilatory (bi)sulfite reductase homologs, DsrABC, encoded in metagenome assembled genomes (MAGs) from spring sediments comprise one of the earliest evolving Dsr lineages. DsrA homologs were expressed in situ under moderately acidic conditions. MAGs lacked genes encoding proteins that activate sulfate prior to (bi)sulfite reduction. This is consistent with sulfide production in enrichment cultures provided sulfite but not sulfate. We suggest input of volcanic sulfur dioxide to anoxic spring-water yields (bi)sulfite and moderately acidic conditions that favor its stability and bioavailability. The presence of similar volcanic springs at the time SRO are thought to have originated (>3.4?Ga) may have supplied (bi)sulfite that supported ancestral SRO. These observations coincide with the lack of inferred SO42? reduction capacity in nearly all organisms with early-branching DsrAB and which are near universally found in hydrothermal environments.Cook, L.L., Drollette, B.D., Edwards, M.R., Benton, L.D., Boehm, P.D., 2020. A data-driven framework for defining stages of oil weathering. Marine Pollution Bulletin 154, 111091. weathering is often described subjectively after a spill. Adjectives like “moderate” and “severe” help define the extent of oil loss but fail to communicate quantitatively and reproducibly the degree of weathering. The use of subjective weathering terms often leads to misperceptions about persistence and toxicity of oil residues in the environment. The weathering of MC252 oil from the Deepwater Horizon spill started immediately after release during the 1500-m ascent to the sea surface and continued as it was transported on the surface and reached the shoreline. Weathering processes included evaporation, dissolution, photo-degradation, and biodegradation, among others. With extensive sample collection and detailed chemistry and source fingerprinting analyses, the Deepwater Horizon data provide a unique opportunity to evaluate weathering processes semi-quantitatively. An objective method of defining the degree of oil weathering is developed based on the detailed chemical results for over 700 MC252 oil samples from the environment.Courel, B., Robson, H.K., Lucquin, A., Dolbunova, E., Oras, E., Adamczak, K., Andersen, S.H., Astrup, P.M., Charniauski, M., Czekaj-Zastawny, A., Ezepenko, I., Hartz, S., Kabaciński, J., Kotula, A., Kukawka, S., Loze, I., Mazurkevich, A., Piezonka, H., Pili?iauskas, G., S?rensen, S.A., Talbot, H.M., Tkachou, A., Tkachova, M., Wawrusiewicz, A., Meadows, J., Heron, C.P., Craig, O.E., 2020. Organic residue analysis shows sub-regional patterns in the use of pottery by Northern European hunter–gatherers. Royal Society Open Science 7, 192016. introduction of pottery vessels to Europe has long been seen as closely linked with the spread of agriculture and pastoralism from the Near East. The adoption of pottery technology by hunter–gatherers in Northern and Eastern Europe does not fit this paradigm, and its role within these communities is so far unresolved. To investigate the motivations for hunter–gatherer pottery use, here, we present the systematic analysis of the contents of 528 early vessels from the Baltic Sea region, mostly dating to the late 6th–5th millennium cal BC, using molecular and isotopic characterization techniques. The results demonstrate clear sub-regional trends in the use of ceramics by hunter–gatherers; aquatic resources in the Eastern Baltic, non-ruminant animal fats in the Southeastern Baltic, and a more variable use, including ruminant animal products, in the Western Baltic, potentially including dairy. We found surprisingly little evidence for the use of ceramics for non-culinary activities, such as the production of resins. We attribute the emergence of these sub-regional cuisines to the diffusion of new culinary ideas afforded by the adoption of pottery, e.g. cooking and combining foods, but culturally contextualized and influenced by traditional practices.Criado-Navarro, I., Mena-Bravo, A., Calderón-Santiago, M., Priego-Capote, F., 2020. Profiling analysis of phospholipid fatty acids in serum as a complement to the comprehensive fatty acids method. Journal of Chromatography A 1619, 460965. acids (FAs) are mostly found in blood as triglycerides, phospholipids (PLs) and cholesteryl esters. Determination of FAs is typically carried out in serum or plasma by a comprehensive method (known as the classical FAMEs method since FAs are determined as Fatty Acids Methyl Esters), which is based on liquid–liquid extraction, derivatization by transesterification, and determination by gas chromatography (GC) coupled to a suited detection technique. However, this method does not favor the determination of FAs that are chemically conjugated in PLs due to kinetics impediment. For this reason, we have developed a selective method to determine the FAs profile of PLs in serum based on solid-phase extraction (SPE) for isolation of PLs and determination of the FAME derivatives by GC–mass spectrometry (GC–MS). The method was applied to serum samples collected from twenty-five individuals to compare the FAs profile versus that provided by the non-selective protocol based on liquid–liquid extraction of lipid families. Statistical analysis revealed compositional changes in the FAs profile with special emphasis on the content of saturated (SFAs) and monounsaturated FAs (MUFAs). Thus, SFAs passed from 34.0% with the classical method to 49.3% in PLs while MUFAs went from 24.4% to 11.4%. This study proves that the proposed method provides complementary results to the comprehensive method and, therefore, both methods can be combined to evaluate the effect of intervention diets and their connection to metabolic diseases.Criscuolo, A., Zeller, M., Fedorova, M., 2020. Evaluation of lipid in-source fragmentation on different Orbitrap-based mass spectrometers. Journal of the American Society for Mass Spectrometry 31, 463-466. lipidomes represent a complex mixture of lipid molecular species with a variety of biological and signaling functions. Modern mass spectrometry (MS)-based analytical platforms are often used to resolve the complexity of natural lipidomes. The quantitative transfer of lipid molecular species in the gas phase during the electrospray ionization required for MS analysis might be challenged by lipid in-source fragmentation (ISF) hampering their accurate identification and quantification. Here we evaluated the effect of transmission radio frequency (RF) levels and ion transfer temperatures (ITTs) on the analysis of four different lipids (ceramide, cholesteryl ester, phosphatidylethanolamine, and triacylglyceride) ionized in positive ion mode on three different Orbitrap-based platforms. ITT and RF levels were ramped in a systematic way to determine the best settings, allowing the most sensitive detection accompanied by the lowest ISF of a lipid. The extent of the ISF was shown to depend on the configurations of the transmission devices (S-lens vs letterbox/ion funnel) at defined RF and ITT levels for each studied lipid class. We provide here the recommendations for reducing the extent of lipid ISF without a significant loss in sensitivity for Q Exactive HF, Q Exactive HF-X, and Orbitrap Fusion Lumos platforms.Cui, G., Tan, Y., Chen, T., Feng, X.-T., Elsworth, D., Pan, Z., Wang, C., 2020. Multidomain two-phase flow model to study the impacts of hydraulic fracturing on shale gas production. Energy & Fuels 34, 4273-4288. fracturing enhances the recovery of gas from ultralow permeability shales, into which water-based fracturing fluids, proppants, and activators are typically injected. However, the impacts of the existing complex multidomain response of a heterogeneous mineral and organic matrix and fractures on the resulting heterogeneity of reservoir transport properties caused by the hydraulic fracturing remain poorly understood. To address this defect, a multidomain multiphysics model is constructed to represent a two-phase flow within a three-component heterogeneous solid system (mineral and organic matrix and fractures) representing the functional complexity of the medium. This model partitions the shale reservoir into a stimulated reservoir volume (SRV) enclosed within an unstimulated reservoir volume (USRV). Different from the previous work, the shape of the SRV is treated as the spheroid instead of the rectangular shape and the size can be determined from the spatial distribution of microseismic events rather than artificially assumed. A two-phase flow model is established for both regions with the impacts of the effective stress variation on the fracture permeability considered and solved with a finite element formalism. The fidelity of the model is first verified using two field data sets from the Barnett and Marcellus shales with good fits achieved against time histories of production. Numerical studies then investigate the impacts of relevant parameters on shale gas production behavior; specially, the impacts of the effective stress and the existence of proppants are first reported. The variations in relative permeability and intrinsic permeability within the SRV are shown to dominate the early-time response of the gas flow rate. The long-term response is mainly dependent on the mass supply from the matrix system and the encapsulating USRV region. The effectiveness of hydraulic fracturing optimized as the SRV region is maximally extended in the horizontal direction and where the increase in permeability is a convex function against a concave function. The distal transport and placement of the proppant remarkably enhance the gas production rate and resist its decline as a result of the evolving high formation stress developed by pressure drawdown. For the selection of proppant type and placement, the resulting permeability and compressibility are of complementary importance as the first controls the initial gas flow rate, whereas the second determines the permeability trend with time. Proppant permeability decreases near-linearly for a constant compressibility but exponentially where compressibility is updated to represent the true response of the proppant pack. The proposed model applies a new approach for optimizing the hydraulic fracturing process and for analyzing the shale gas production behavior.Cui, J., Huang, L., Wang, W., Xu, P., Zanaroli, G., Tang, H., 2020. Maximization of the petroleum biodegradation using a synthetic bacterial consortium based on minimal value algorithm. International Biodeterioration & Biodegradation 150, 104964. pollution is a global concern because it causes serious environmental and human health problems. Microbial communities play important roles in petroleum biodegradation. In this study, a synthetic bacterial consortium for efficiently degrading ability was constructed on the basis of a minimal value algorithm running on MATLAB. Functional microbial diversity-based screening of three petroleum-degrading strains, Achromobacter sp. P3, Sphingobium sp. P10 and Rhizobium sp. P14, enabled the initial synthesis of the bacterial consortium in combination with a previously used bacterial consortium PDM. When 27.0% of P3, 21.0% of P10, 28.0% of P14 and 24.0% of consortium PDM were inoculated to a petroleum medium, 78.9% of petroleum was degraded under the optimal conditions. The synthetic bacterial consortium has 34.8% higher petroleum degradation than the original bacterial community PDM. Total 40% of the petroleum in the contaminated soil was removed after 20 days of soil bioremediation using the reconstructed consortium. This is an attempt to remediate petroleum-contaminated pollution with synthetic biology via reconstructing a synthetic bacterial community, providing a new idea for the remediation of other pollution problems.D’Avila, F.G., Silva, C.M.F., Steckel, L., Ramos, A.C.S., Lucas, E.F., 2020. Influence of asphaltene aggregation state on the wax crystallization process and the efficiency of EVA as a wax crystal modifier: A study using model systems. Energy & Fuels 34, 4095-4105. precipitation/deposition of waxes poses a major problem for the production and transport of petroleum. Understanding the factors that affect this problem is very important to select preventive actions. The influence of asphaltenes on the behavior of waxes has not been widely explored in the literature and is still controversial. The objective of this work was to assess the influence of the asphaltene aggregation state (by varying the solvent quality) on the behavior of waxes and the performance of a wax deposition inhibitor using model systems. A commercial wax (melting point 53–57 °C), asphaltenes C7I, and poly(ethylene-co-vinyl acetate) were used in this study. The wax appearance temperature (WAT) was determined by microcalorimetry (μDSC), the flow behavior as a function of temperature was investigated by measuring viscosity, and the morphology of the wax crystals was evaluated by optical microscopy. The presence of asphaltenes C7I in the dispersed state did not affect the WAT, but in the aggregated state, they led to a reduction in the WAT at the asphaltene/wax ratio of 0.1%. The asphaltenes C7I acted to reduce the viscosity of the systems at temperatures below the WAT when compared to the behavior of the respective system free of asphaltenes, but the intensity of the viscosity reduction varied with the aggregation state of the asphaltenes: in the aggregation state immediately before the precipitation onset condition, the asphaltenes caused the lowest viscosities. There was a synergistic effect between the asphaltenes C7I and the wax deposition inhibitor to decrease the viscosity of the model system below the WAT.Dai, X., Lv, J., Yan, G., Chen, C., Guo, S., Fu, P., 2020. Bioremediation of intertidal zones polluted by heavy oil spilling using immobilized laccase-bacteria consortium. Bioresource Technology 309, 123305. oil pollution in the intertidal zones has become a worldwide environmental problem. In this study, bioremediation on heavy oil pollutants in the intertidal zones using an immobilized laccase-bacteria consortium system was evaluated with the aid of intertidal experimental pools built in the coastal area. It is found that degradation efficiency of the immobilized laccase-bacteria consortium for heavy oil was 66.5% after 100?days remediation, with the reaction rate constant of 0.018 d?1. Gas Chromatograph-Mass Spectrometer analysis shows that degradation efficiency of saturated hydrocarbons and aromatic hydrocarbons were 79.2% and 78.7%, which were 64.9% and 65.1% higher than control. It is further seen that degradation of long-chain n-alkanes of C26-C35 and polycyclic aromatic hydrocarbons with more than three rings were significant. Metagenomic analysis indicates that the immobilized laccase-bacterial consortium has not only increased the biodiversity of heavy oil degrading bacteria, but also accelerated the degradation of heavy oil.Damiani, C., Gaglio, D., Sacco, E., Alberghina, L., Vanoni, M., 2020. Systems metabolomics: from metabolomic snapshots to design principles. Current Opinion in Biotechnology 63, 190-199. is a rapidly expanding technology that finds increasing application in a variety of fields, form metabolic disorders to cancer, from nutrition and wellness to design and optimization of cell factories. The integration of metabolic snapshots with metabolic fluxes, physiological readouts, metabolic models, and knowledge-informed Artificial Intelligence tools, is required to obtain a system-level understanding of metabolism. The emerging power of multi-omic approaches and the development of integrated experimental and computational tools, able to dissect metabolic features at cellular and subcellular resolution, provide unprecedented opportunities for understanding design principles of metabolic (dis)regulation and for the development of precision therapies in multifactorial diseases, such as cancer and neurodegenerative diseases.Danczak, R.E., Daly, R.A., Borton, M.A., Stegen, J.C., Roux, S., Wrighton, K.C., Wilkins, M.J., 2020. Ecological assembly processes are coordinated between bacterial and viral communities in fractured shale ecosystems. mSystems 5, e00098-20.: The ecological drivers that concurrently act upon both a virus and its host and that drive community assembly are poorly understood despite known interactions between viral populations and their microbial hosts. Hydraulically fractured shale environments provide access to a closed ecosystem in the deep subsurface where constrained microbial and viral community assembly processes can be examined. Here, we used metagenomic analyses of time-resolved-produced fluid samples from two wells in the Appalachian Basin to track viral and host dynamics and to investigate community assembly processes. Hypersaline conditions within these ecosystems should drive microbial community structure to a similar configuration through time in response to common osmotic stress. However, viral predation appears to counterbalance this potentially strong homogeneous selection and pushes the microbial community toward undominated assembly. In comparison, while the viral community was also influenced by substantial undominated processes, it assembled, in part, due to homogeneous selection. When the overall assembly processes acting upon both these communities were directly compared with each other, a significant relationship was revealed, suggesting an association between microbial and viral community development despite differing selective pressures. These results reveal a potentially important balance of ecological dynamics that must be in maintained within this deep subsurface ecosystem in order for the microbial community to persist over extended time periods. More broadly, this relationship begins to provide knowledge underlying metacommunity development across trophic levels.Importance: Interactions between viral communities and their microbial hosts have been the subject of many recent studies in a wide range of ecosystems. The degree of coordination between ecological assembly processes influencing viral and microbial communities, however, has been explored to a much lesser degree. By using a combined null modeling approach, this study investigated the ecological assembly processes influencing both viral and microbial community structure within hydraulically fractured shale environments. Among other results, significant relationships between the structuring processes affecting both the viral and microbial community were observed, indicating that ecological assembly might be coordinated between these communities despite differing selective pressures. Within this deep subsurface ecosystem, these results reveal a potentially important balance of ecological dynamics that must be maintained to enable long-term microbial community persistence. More broadly, this relationship begins to provide insight into the development of communities across trophic levels.Davies, M.A., Schr?der-Adams, C.J., Herrle, J.O., Hülse, P., Schneider, S., 2020. Bottom water redox conditions and benthic foraminiferal morphogroup response in the Late Cretaceous Sverdrup Basin, Arctic Canada: Implications for Oceanic Anoxic Event 3. Cretaceous Research 111, 104449. anoxic events (OAEs) represent significant perturbations in the global carbon cycle and therefore studying these events is critical for understanding drivers of carbon burial and variable oxygen conditions under a Cretaceous greenhouse climate mode. Here we present whole rock geochemical and benthic foraminiferal morphogroup data from two localities in the Sverdrup Basin in the High Arctic of Canada to investigate bottom water redox conditions during the Coniacian to Santonian OAE 3 interval. Major element geochemistry reflects lithological change and is related to shoreline proximity. Evidence for bottom water anoxia in the Late Cretaceous of the Sverdrup Basin is lacking and benthic dysoxia was limited to the Coniacian interval at the basin margin. Dysoxic conditions were characterized by elevated Mo concentrations and small epifaunal trochamminid species adapted to tolerate low oxygen levels. Elevated total organic carbon (TOC) in the Sverdrup Basin was related to relative sea-level changes, with increased erosion and terrestrial organic matter flux during transgression that promoted primary production. During transgressions to highstands, the Sverdrup Basin may have acted as a minor sink of carbon due to increased organic matter flux, potentially contributing to CO2 drawdown in the Late Cretaceous. Our comparison of six records across the Sverdrup and Western Interior basins demonstrates that no distinct OAE 3 interval can be determined based on the timing of benthic dysoxia to anoxia, TOC increases, and carbon isotopic excursions. Instead, organic burial records are driven by local tectonics influencing transgressive/regressive phases that are accentuated in shallows seas.de Bar, M.W., Weiss, G., Yildiz, C., Rampen, S.W., Lattaud, J., Bale, N.J., Mienis, F., Brummer, G.-J.A., Schulz, H., Rush, D., Kim, J.-H., Donner, B., Knies, J., Lückge, A., Stuut, J.-B.W., Sinninghe Damsté, J.S., Schouten, S., 2020. Global temperature calibration of the Long chain Diol Index in marine surface sediments. Organic Geochemistry 142, 103983. Long chain Diol Index (LDI) is a relatively new organic geochemical proxy for sea surface temperature (SST), based on the abundance of the C30 1,15-diol relative to the summed abundance of the C28 1,13-, C30 1,13- and C30 1,15-diols. Here we substantially extend and re-evaluate the initial core top calibration by combining the original dataset with 172 data points derived from previously published studies and 262 newly generated data points. In total, we considered 595 globally distributed surface sediments with an enhanced geographical coverage compared to the original calibration. The relationship with SST is similar to that of the original calibration but with considerably increased scatter. The effects of freshwater input (e.g., river runoff) and long-chain diol contribution from Proboscia diatoms on the LDI were evaluated. Exclusion of core-tops deposited at a salinity?<?32 ppt, as well as core-tops with high Proboscia-derived C28 1,12-diol abundance, resulted in a substantial improvement of the relationship between LDI and annual mean SST. This implies that the LDI cannot be directly applied in regions with a strong freshwater influence or high C28 1,12-diol abundance, limiting the applicability of the LDI. The final LDI calibration (LDI?=?0.0325?×?SST?+?0.1082; R2?=?0.88; n?=?514) is not statistically different from the original calibration of Rampen et al. (2012) (), although with a larger calibration error of 3?°C. This larger calibration error results from several regions where the LDI does not seem to have a strong temperature dependence with annual mean SST, posing a limitation on the application of the LDI.De Haan, D.O., Jansen, K., Rynaski, A.D., Sueme, W.R.P., Torkelson, A.K., Czer, E.T., Kim, A.K., Rafla, M.A., De Haan, A.C., Tolbert, M.A., 2020. Brown carbon production by aqueous-phase interactions of glyoxal and SO2. Environmental Science & Technology 54, 4781-4789. acid and sulfate salts are major components of aerosol particles. Here, we explore the potential for their respective precursor species, glyoxal and SO2, to form atmospheric brown carbon via aqueous-phase reactions in a series of bulk aqueous and flow chamber aerosol experiments. In bulk aqueous solutions, UV- and visible-light-absorbing products are observed at pH 3–4 and 5–6, respectively, with small but detectable yields of hydroxyquinone and polyketone products formed, especially at pH 6. Hydroxymethanesulfonate (HMS), C2, and C3 sulfonates are major products detected by electrospray ionization mass spectrometry (ESI-MS) at pH 5. Past studies have assumed that the reaction of formaldehyde and sulfite was the only atmospheric source of HMS. In flow chamber experiments involving sulfite aerosol and gas-phase glyoxal with only 1 min residence times, significant aerosol growth is observed. Rapid brown carbon formation is seen with aqueous aerosol particles at >80% relative humidity (RH). Brown carbon formation slows at 50–60% RH and when the aerosol particles are acidified with sulfuric acid but stops entirely only under dry conditions. This chemistry may therefore contribute to brown carbon production in cloud-processed pollution plumes as oxidizing volatile organic compounds (VOCs) interact with SO2 and water.Dean, J.F., Meisel, O.H., Martyn Rosco, M., Marchesini, L.B., Garnett, M.H., Lenderink, H., van Logtestijn, R., Borges, A.V., Bouillon, S., Lambert, T., R?ckmann, T., Maximov, T., Petrov, R., Karsanaev, S., Aerts, R., van Huissteden, J., Vonk, J.E., Dolman, A.J., 2020. East Siberian Arctic inland waters emit mostly contemporary carbon. Nature Communications 11, 1627. waters (rivers, lakes and ponds) are important conduits for the emission of terrestrial carbon in Arctic permafrost landscapes. These emissions are driven by turnover of contemporary terrestrial carbon and additional pre-aged (Holocene and late-Pleistocene) carbon released from thawing permafrost soils, but the magnitude of these source contributions to total inland water carbon fluxes remains unknown. Here we present unique simultaneous radiocarbon age measurements of inland water CO2, CH4 and dissolved and particulate organic carbon in northeast Siberia during summer. We show that >80% of total inland water carbon was contemporary in age, but pre-aged carbon contributed >50% at sites strongly affected by permafrost thaw. CO2 and CH4 were younger than dissolved and particulate organic carbon, suggesting emissions were primarily fuelled by contemporary carbon decomposition. Our findings reveal that inland water carbon emissions from permafrost landscapes may be more sensitive to changes in contemporary carbon turnover than the release of pre-aged carbon from thawing permafrost.Delmonte, P., Belaunzaran, X., Ridge, C.D., Aldai, N., Kramer, J.K.G., 2020. Separation and characterization of products from acidic methanolysis of plasmalogenic lipids by two-dimensional gas chromatography with online reduction. Journal of Chromatography A 1619, 460955. complexity of determining the composition of animal tissue lipids is greatly increased by the presence of plasmalogens in which the alkyl chain is linked to glycerol by an enol ether bond instead of being esterified. Acidic methanolysis of animal tissue lipids provides the simultaneous scission of acyl and alkenyl ether moieties, but the complexity of the products of reaction poses a great challenge in their gas chromatographic analysis. Two-dimensional gas chromatography with online reduction (GC-OR × GC) provided the resolution of all components contained in acid methanolyzed animal lipids, taking advantage of the selective hydrogenation of alkenyl ether methanolysis products prior to the second-dimension separation (2D). In this study, we also studied the chemical transformations occurring during the acidic methanolysis of animal lipids and the subsequent gas chromatographic analysis. In particular, we observed that using methanolysis reagents contaminated with water resulted in the undesired formation of fatty aldehydes, and we made recommendations on how to avoid these side reactions using proper methanolysis conditions. Products of acidic methanolysis were studied by GC-OR × GC, GC-MS, NMR spectroscopy, and GC with flame ionization detection (GC-FID). We defined the GC-FID elution order of animal lipid acidic methanolysis products using 100 m × 0.25 mm 100% bis(cyanopropyl)siloxane columns and two different set of elution conditions: isothermal elution at 180°C, and a temperature program optimized for dairy fats. A simple procedure for isolating dimethyl acetals (DMA) prior to GC analysis is also described.Deng, J., Du, Z., Karki, B.B., Ghosh, D.B., Lee, K.K.M., 2020. A magma ocean origin to divergent redox evolutions of rocky planetary bodies and early atmospheres. Nature Communications 11, 2007. oceans were once ubiquitous in the early solar system, setting up the initial conditions for different evolutionary paths of planetary bodies. In particular, the redox conditions of magma oceans may have profound influence on the redox state of subsequently formed mantles and the overlying atmospheres. The relevant redox buffering reactions, however, remain poorly constrained. Using first-principles simulations combined with thermodynamic modeling, we show that magma oceans of Earth, Mars, and the Moon are likely characterized with a vertical gradient in oxygen fugacity with deeper magma oceans invoking more oxidizing surface conditions. This redox zonation may be the major cause for the Earth’s upper mantle being more oxidized than Mars’ and the Moon’s. These contrasting redox profiles also suggest that Earth’s early atmosphere was dominated by CO2 and H2O, in contrast to those enriched in H2O and H2 for Mars, and H2 and CO for the Moon.Deng, X., Pan, S., Zhang, J., Wang, Z., Jiang, Z., 2020. Numerical investigation on abnormally elevated pressure in laboratory-scale porous media caused by depressurized hydrate dissociation. Fuel 271, 117679. dissociation induced by artificial or environmental factors in submarine sediments may lead to drilling risks, submarine landslides, and the collapse of offshore platforms—all of which are associated with suddenly increased pore pressure. This study establishes a coupled model for the two-phase flow of fluids in porous media in which the pore pressure of water and gas are used as dependent variables and heat transfer and hydrate dissociation equations are combined. The simulation results of the model are consistent with Masuda’s experimental dataset. A quantifiable controlling hydrate dissociation specific reaction surface area (SRSA) model and an absolute permeability model are proposed to conduct numerical simulations of laboratory-scale hydrate cores, with the aim to investigate the mechanism of hydrate dissociation-induced geological hazard initiation and a law of their evolution in sediments. The results show that i) suddenly depressurized hydrate dissociation in porous media can be divided into three phases—pressure induction, transition, and temperature-controlled—and that the first two are much shorter than the third. Moreover, the lower initial permeability results in a shorter holding period for the first stage, and the transition phase becomes indistinguishable; conversely, the larger initial permeability makes the three stages more distinguishable; ii) hardly increasing the core permeability during the intermediate stage of hydrate dissociation makes the pore pressure rebound. However, the steep increase in SRSA does not result in a significant pore gas pressure rebound; conversely, a larger SRSA does facilitate pore pressure dissipation. This work provides theoretical and laboratory-scale model analyses for the safe development of natural gas hydrates bearing in marine sediments.Ding, L., Qi, Y., Shan, S., Ge, T., Luo, C., Wang, X., 2020. Radiocarbon in dissolved organic and inorganic carbon of the South China Sea. Journal of Geophysical Research: Oceans 125, e2020JC016073.: We present the carbon isotope (14C and 13C), dissolved inorganic carbon (DIC), and dissolved organic carbon (DOC) concentration measurements in the South China Sea (SCS) to reveal the different sources and cycling time scales of the two major carbon pools in the SCS. The DIC concentrations ranged from 1,776 to 2,328 μmol kg?1, and they were lower at the surface and increased with depth. Conversely, the DOC concentrations ranged from 38 to 95 μM, and they were higher on the surface and decreased rapidly in the upper 500‐m water depth. The DIC Δ14C and DOC Δ14C values varied from ?227‰ to 68‰ and ?557‰ to ?258‰, respectively, and both decreased with depth until 1,500 m and then remained relatively constant. DOC Δ14C values were ?330‰ lower than DIC Δ14C, indicating that DOC has cycled for much longer than DIC in the SCS. The lower Δ14C‐DIC and Δ14C‐DOC values at depths shallower than 700 m were mainly influenced by intensified vertical mixing, which upwelled the deep water with low Δ14C‐DIC and Δ14C‐DOC values for thorough mixture with the upper layer water. Conversely, the small difference in the Δ14C signature in deep water (>1,500 m) between the SCS and the North Pacific confirmed the rapid water exchange through the Luzon Strait and rapid water mixing in the SCS basin, which plays an important role in controlling carbon cycling in the deep SCS.Plain Language Summary: Dissolved inorganic carbon (DIC) is the largest carbon pool in the ocean and is closely linked to dissolved organic carbon (DOC), which is the largest exchangeable organic carbon pool in the ocean. Both DIC and DOC play important roles in the global carbon cycle, but their sources, distribution, and cycling time are different and controlled by different processes in the ocean. Here we report radiocarbon and stable carbon isotope measurements of DIC and DOC collected in the South China Sea (SCS) to reveal the sources and cycling time scales of the two major carbon pools in the SCS. The Δ14C values and 14C ages indicate that DOC has cycled for much longer than DIC in the SCS. The rapid water exchange and mixing between the SCS and the Kuroshio Current in the Northwestern Pacific play important roles in controlling the distributions and cycling of DIC and DOC in the SCS.Ding, Y., Chen, D., Zhou, X., Huang, T., Guo, C., Yeasmin, R., 2020. Paired δ13Ccarb-δ13Corg evolution of the Dengying Formation from northeastern Guizhou and implications for stratigraphic correlation and the Late Ediacaran carbon cycle. Journal of Earth Science 31, 342-353. study provides δ13C profiles from a lower-slope (Well ZK102) to basin (Bahuang Section) environment to better understand the temporal and spatial variability in δ13Ccarb-δ13Corg of the Yangtze Block during the Late Ediacaran. Our new δ13C profiles together with the reported data suggest that the Upper Ediacaran successions from different depositional environments are generally bounded by negative δ13Ccarb and/or δ13Corg excursions in the underlying and overlying strata. Moreover, the Upper Ediacaran δ13Ccarb profiles generally can be subdivided into two positive excursions and an interjacent negative excursion, whereas the paired δ13Corg profiles from different depositional environments have individual variation trends. On the other hand, these data show a large surface-to-deep water δ13C gradient (~5‰ variation in δ13Ccarb, >10‰ variation in δ13Corg) which can be reasonably explained by the heterogeneity of the biological activities in the redox-stratified water column. Furthermore, the decoupled δ13Ccarb-δ13Corg pattern with large δ13Corg perturbations at the lower slope precluded the existence of a large dissolved organic carbon reservoir at the Yangtze Block during the Late Ediacaran. Thus, the high δ13Ccarb values in the Upper Ediacaran succession could be balanced by large amounts of buried organic carbon likely associated with high productivity.Ding, Z., Wang, R., Chen, F., Yang, J., Zhu, Z., Yang, Z., Sun, X., Xian, B., Li, E., Shi, T., Zuo, C., Li, Y., 2020. Origin, hydrocarbon accumulation and oil-gas enrichment of fault-karst carbonate reservoirs: A case study of Ordovician carbonate reservoirs in South Tahe area of Halahatang oilfield, Tarim Basin. Petroleum Exploration and Development 47, 306-317. on comprehensive analysis of tectonic and fault evolution, core, well logging, seismic, drilling, and production data, the reservoir space characteristic, distribution, origin of fault-karst carbonate reservoir in Yueman block of South Tahe area, Halahatang oilfield, Tarim Basin, were studied systematically. And the regular pattern of hydrocarbon accumulation and enrichment was analyzed systematically based on development practice of the reservoirs. The results show that fault-karst carbonate reservoirs are distributed in the form of “body by body” discontinuously, heterogeneously and irregularly, which are controlled by the development of faults. Three formation models of fault-karst carbonate reservoirs, namely, the models controlled by the main deep-large fault, the secondary fault and the secondary internal fault, are built. The hydrocarbon accumulation and enrichment of fault-karst carbonate reservoirs is controlled by the spatiotemporal matching relation between hydrocarbon generation period and fault activity, and the size and segmentation of fault. The study results can effectively guide the well deployment and help the efficient development of fault-karst carbonate reservoirs of South Tahe area, Halahatang oilfield.Domingues, V.S., de Souza Monteiro, A., Júlio, A.D.L., Queiroz, A.L.L., dos Santos, V.L., 2020. Diversity of metal-resistant and tensoactive-producing culturable heterotrophic bacteria isolated from a copper mine in Brazilian Amazonia. Scientific Reports 10, 6171. extracellular polymeric substances (EPSs) present diverse properties of biotechnological interest, such as surface modification, metal adsorption and hydrophobic substances solubilization through surface tension reduction. Thus, there is a growing demand for new producing strains and structurally variable biomolecules with different properties. One approach for scanning this biodiversity consists of exploring environments under selective pressures. The aim of this study was to evaluate the composition of culturable heterotrophic bacterial communities from five different sites from a copper mine in the Amazon biome by an enrichment technique to obtain metal resistant bacteria (lead, arsenic, cadmium, copper and zinc) capable of producing EPSs. The bacterial densities at the sites varied from 2.42 × 103 to 1.34 × 108 NMP mL?1 and the 77 bacterial isolates obtained were classified in four divisions, β-Proteobacteria (16.88%), γ-Proteobacteria (7.29%), Firmicutes (61%) and Actinobacteria (12.98%). Bacillus, Alcaligenes, and Lysinibacillus were the most dominant among the 16 observed genera, but the relative frequency of each varied according to the sample and the metal used in the enrichment culture. 58% of the bacterial strains (45) could produce EPSs. From these, 33 strains showed emulsifying activity (E24), and 9 of them reached values higher than 49%. Only Actinomyces viscosus E3.Pb5 and Bacillus subtilis group E3.As2 reduced the medium surface tension to values lower than 35 mN m?1. It was possible to confirm the high presence of bacteria capable of producing EPSs with tensoactive properties in Amazon copper mines and the evolutionary pressure exerted by the heavy metals during enrichment. These molecules can be tested as an alternative for use in processes that involve the removal of metals, such as the bioremediation of contaminated environments.Domínguez, I., Arrebola, F.J., Martínez Vidal, J.L., Garrido Frenich, A., 2020. Assessment of wastewater pollution by gas chromatography and high resolution Orbitrap mass spectrometry. Journal of Chromatography A 1619, 460964. a novelty, the combination of headspace solid phase microextraction and gas chromatography coupled to an Orbitrap mass analyzer in full scan mode (HS-SPME-GC-Orbitrap-MS) was evaluated for the monitoring of organic pollutants in wastewaters. The developed methodology showed good linearity (R2 > 0.999), sensitivity as well as suitable relative recoveries (89–115%) and precision values (RSD = 1–16%) for 15 polycyclic aromatic hydrocarbons (PAHs) selected as target compounds. Naphthalene, acenapthene and phenanthrene were found in the analyzed samples (influent and effluent wastewaters). Naphthalene was present in 62% of them, ranging from 1.33 to 24.32 ng L?1. Acenapthene was observed in 1 single sample (4.17 ng L?1) while phenanthrene was found in 7 samples (1.51–8.67 ng L?1).In addition, in order to identify other pollutants in the samples, retrospective analyses were addressed through target and non-target screenings. An in-house database containing close to 1,000 pollutants including, among others, polychlorinated biphenyls (PCBs), brominated diphenyl ethers (BDEs) and pesticides, was applied in the post-target analysis. For the non-target screening, after a deconvolution process, high resolution filtering (HRF) and Kovats retention index (KI) were used for tentative analyte identification. Thus, 51 additional pollutants were tentatively identified in the wastewaters, most of them used as flavoring agents and household product ingredients, highlighting the presence of linear alkyl benzenes (LABs).Doughty, C., Oldenburg, C.M., 2020. CO2 plume evolution in a depleted natural gas reservoir: Modeling of conformance uncertainty reduction over time. International Journal of Greenhouse Gas Control 97, 103026. in the long-term fate of CO2 injected for geologic carbon sequestration (GCS) is a significant barrier to the adoption of GCS as a greenhouse-gas emission-mitigation for industry and regulatory agencies alike. We present a modeling study that demonstrates that the uncertainty in forecasts of GCS site performance decreases over time as monitoring data are used to update operational models. We consider a case study of GCS in a depleted natural gas reservoir, with CO2 injection occurring over 20 years, with a 50-year post-injection site care period. We constructed a detailed model to generate the actual model output, which is considered synthetic observation data. A series of simpler operational models based on limited data and assumptions about how an operator would model such a site are then run and compared against actual model output at specific monitoring points after one year, two years, etc. The operational model is updated and improved using the synthetic observation data from the actual model at the same time intervals. Model parameter values and model features needed to be updated over time to improve matches to the actual model. These kinds of model adjustments would be a normal part of reservoir engineering and site management at GCS sites. Uncertainty in two key measures related to site performance decreases with time: extent of the CO2 plume up-dip migration, and radial extent of the pressure pulse. This conclusion should help allay the concerns of industry and regulators about uncertainty in long-term fate of CO2 at GCS sites.Douglas, G.S., Graan, T.P., Hardenstine, J.H., 2020. Forensic identification and quantification of oil sands-based bitumen released into a complex sediment environment. Marine Pollution Bulletin 155, 111141. or about July 25, 2010, approximately 843,000?gal of condensate diluted bitumen (dilbit, a heavy oil) was released into the Kalamazoo River near Marshall, Michigan. As the discharged Line 6B oil migrated downstream the lighter diluent volatilized, formed visible oil droplets/flakes in the water column, became denser than water and/or became aggregated with sediment and migrated to the underlying bottom sediments. Accurate identification and determination of the amount of Line 6B oil present in the sediment was a primary requirement for remediation and allocation of liability. Based on a multi-tiered application of advanced hydrocarbon fingerprinting methodology, key chemical characteristics of the spilled oil were identified that allow for distinguishing heavy oil-related contamination from the complex river sediment background hydrocarbon contamination. It was determined that among the characteristics evaluated, concentration ratios of selected tri-aromatic steranes and triterpanes were most efficient parameters for identification and quantification of the spilled oil in the environment. This quantification approach was successfully applied and validated with field sample results and is consistent with the well-established environmental stability of these petroleum biomarkers and modern hydrocarbon fingerprinting methodology.Du, Y., Chiari, M., Karádi, V., Nicora, A., Onoue, T., Pálfy, J., Roghi, G., Tomimatsu, Y., Rigo, M., 2020. The asynchronous disappearance of conodonts: New constraints from Triassic-Jurassic boundary sections in the Tethys and Panthalassa. Earth-Science Reviews 203, 103176. End-Triassic Extinction event (ETE) has been recognized in numerous sections worldwide and it is usually marked by three negative carbon isotope excursions (NCIEs), named “precursor” (P-NCIE), “initial” (I-NCIE) and “main” (M-NCIE) negative carbon isotope excursions. These three NCIEs are significant characteristics of this time interval, and they are likely related to the emplacement of the Central Atlantic Magmatic Province (CAMP) that is considered the main trigger of the ETE. Stable carbon isotope excursions, commonly related to biotic turnovers and extinctions, play an important role in stratigraphic correlations, particularly around the Triassic-Jurassic boundary (TJB). This time interval records the disappearance of conodonts, elements of a feeding apparatus belonging to marine organisms that populated the Paleozoic-early Mesozoic seas, and which became extinct across the TJB. So far, the interpretation of conodont extinction has remained ambiguous, as the timing of its last occurrence was debated which in turn hindered our understanding of the main cause(s) that could have led to their disappearance. Here we present and compare integrated data of nine TJB sections from different areas, Tethys and Panthalassa, and different depositional environments, i.e. shallow vs deep water or proximal vs distal shelf. Each of these sections record both the last occurrences of latest Triassic conodont taxa and pronounced changes in the carbon isotopic composition of organic matter across the TJB interval. Our analysis of chemo- and integrated biostratigraphic correlation suggests that the final extinction of the taxon Conodonta was asynchronous.Du, Y., Fu, C., Pan, Z., Sang, S., Wang, W., Liu, S., Zhao, Y., Zhang, J., 2020. Geochemistry effects of supercritical CO2 and H2O on the mesopore and macropore structures of high-rank coal from the Qinshui Basin, China. International Journal of Coal Geology 223, 103467. effects of supercritical CO2 (scCO2) on coal pores play a critical role in the geological storage of CO2 and enhanced coalbed methane recovery (CO2-ECBM). To investigate the effects of scCO2 - H2O on the mesopore - macropore structure of high-rank coals, a series of experimental simulations and analyses were performed. Coal samples from the Qinshui Basin, China were exposed to scCO2 and deionized water for 240 h at 45 °C and 10 MPa and at 80 °C and 20 MPa. The influences on the pore structure were analyzed by performing a mercury intrusion capillary pressure (MICP) measurement. Using a field emission scanning electron microscope (FE-SEM) and an advanced mineral identification control system (AMICS), the geochemical effects of scCO2-H2O on the same minerals and the same pore or fracture (nanometer to micrometer scale) before and after the reaction were investigated. Based on the changes of the minerals, pores and fractures, the types, targets, expressions, and scopes of the geochemical effects were explored. The experimental results show that after the injection of scCO2 into the coal samples, the pores and fractures were newly generated or expanded under the interactions of mineral dissolution-precipitation, clay hydration and swelling, coal swelling, and pyrite oxidation with gypsum precipitation. Moreover, the largest improvement of the pore volume was observed in pores larger than 30 μm or smaller than 100 nm, and higher temperatures and pressures were beneficial to the formation of large pores and fractures. The change in the specific surface area (SSA) was mainly caused by the change in pore volume. The corrosion of carbonate minerals showed the most significant contribution to the pore volume of full-scale macropores and mesopores, while most geochemical effects on other minerals had impacts on the mesopores and the macropores smaller than 1 μm. The coal swelling had the most significant effect on the connectivity of the pores in the coal reservoir.Dupré, S., Loubrieu, B., Pierre, C., Scalabrin, C., Guérin, C., Ehrhold, A., Ogor, A., Gautier, E., Ruffine, L., Biville, R., Saout, J., Breton, C., Floodpage, J., Lescanne, M., 2020. The Aquitaine shelf edge (Bay of Biscay): A primary outlet for microbial methane release. Geophysical Research Letters 47, e2019GL084561. few thousand (2,612) seeps are releasing microbial methane bubbles from the seafloor at the Aquitaine Shelf edge (Bay of Biscay) at shallow water depths (140–220 m). This methane contributes to the formation of meter‐scale subcircular carbonate structures, which are (sub)outcropping over 375 km2. Based on in situ flow rate measurements and acoustic data, and assuming steady and continuous fluxes over time, the methane entering the water column is estimated at 144 Mg/yr. Microbial methane circulation has been ongoing for at least a few thousand years. This discovery highlights the importance of microbial methane generation, disconnected from deep thermogenic sources and gas hydrates, at continental shelves. The shelf edge may be viewed as a focus area for methane circulation and release and related diagenesis, all having an impact on the shaping of continental shelves and potentially on the oceanic and atmospheric carbon budget.Eckard, R.S., Bergamaschi, B.A., Pellerin, B., Spencer, R.G., Dyda, R., Hernes, P.J., 2020. Organic matter integration, overprinting, and the relative fraction of optically active organic carbon in a human-impacted watershed. Frontiers in Earth Science 8, 67. doi: 10.3389/feart.2020.00067. continually integrate terrestrial organic matter (OM) into their waters, in a process that transfers 1.9 Pg C yr–1 as the primary linkage between oceanic and terrestrial carbon cycles. Yet rivers are not simple, conservative OM integrators. Patchy local land uses (wetlands, bogs, agriculture) release OM that can disproportionately alter river biogeochemistry and overprint upstream carbon. These releases are quantifiable at the plot scale but remain unpredictable across river reaches and watersheds, critically inhibiting our ability to scale up terrestrial-aquatic linkages to regional/global carbon cycling models. We evaluated OM overprinting distance along a human-influenced watershed to quantify river integration of terrestrial OM and to bridge the quantification gap between habitats and waterway biogeochemistry. We investigated changes in dissolved organic carbon (DOC) concentration and dissolved organic matter (DOM) composition (lignin phenols, fluorescence excitation-emission spectra using parallel factor analysis [PARAFAC], and the relative fraction of optically active DOM [EEMDOC]). DOC concentrations increased continually (p < 0.001) downstream, from median 1.0 mg L–1 at 30 km (headwaters) to 3.3 mg L–1 at the river mouth. This rate of increase corresponded to a DOC overprinting distance—the longitudinal distance over which DOC concentrations double—of 13 km. Mainstem DOC overprinting distance ranged from 8 km (winter, rainy season) to 21 km (summer, dry season with irrigation), highlighting stronger overprinting during increased hydraulic connectivity. Stronger overprinting also correlated to higher EEMDOC (p < 0.001). Overprinting distance effectively quantifies river integration of DOM along the terrestrial-aquatic interface, helping to refine bottom-up carbon cycle estimates, inform upscaling of site-specific fluxes, and to track land use and climate influence on river biogeochemistry.Edgecombe, G.D., Strullu-Derrien, C., Góral, T., Hetherington, A.J., Thompson, C., Koch, M., 2020. Aquatic stem group myriapods close a gap between molecular divergence dates and the terrestrial fossil record. Proceedings of the National Academy of Sciences 117, 8966-8972.: Most arthropod diversity is now found on land, with hexapods (insects), arachnids, and myriapods being major terrestrial radiations. Molecular dating consistently predicts that these groups have earlier evolutionary origins than are recorded by fossils. A reason for this difference between molecular- and fossil-based age estimates is that few candidates for marine or freshwater stem groups of these terrestrial lineages have been identified. A Devonian euthycarcinoid arthropod preserves details of the head shared by myriapods, adding support to the theory that they are each other’s closest relative. The fossil record of euthycarcinoids in the Cambrian, including trackways made on tidal flats, clarifies the marine-to-terrestrial transition in the myriapod lineage and reconciles molecular and fossil-based estimates for the timing of myriapod origins.Abstract: Identifying marine or freshwater fossils that belong to the stem groups of the major terrestrial arthropod radiations is a longstanding challenge. Molecular dating and fossils of their pancrustacean sister group predict that myriapods originated in the Cambrian, much earlier than their oldest known fossils, but uncertainty about stem group Myriapoda confounds efforts to resolve the timing of the group’s terrestrialization. Among a small set of candidates for membership in the stem group of Myriapoda, the Cambrian to Triassic euthycarcinoids have repeatedly been singled out. The only known Devonian euthycarcinoid, Heterocrania rhyniensis from the Rhynie and Windyfield cherts hot spring complex in Scotland, reveals details of head structures that constrain the evolutionary position of euthycarcinoids. The head capsule houses an anterior cuticular tentorium, a feature uniquely shared by myriapods and hexapods. Confocal microscopy recovers myriapod-like characters of the preoral chamber, such as a prominent hypopharynx supported by tentorial bars and superlinguae between the mandibles and hypopharynx, reinforcing an alliance between euthycarcinoids and myriapods recovered in recent phylogenetic analysis. The Cambrian occurrence of the earliest euthycarcinoids supplies the oldest compelling evidence for an aquatic stem group for either Myriapoda or Hexapoda, previously a lacuna in the body fossil record of these otherwise terrestrial lineages until the Silurian and Devonian, respectively. The trace fossil record of euthycarcinoids in the Cambrian and Ordovician reveals amphibious locomotion in tidal environments and fills a gap between molecular estimates for myriapod origins in the Cambrian and a post-Ordovician crown group fossil record.El-Bassi, L., Ziadi, I., Belgacem, S., Bousselmi, L., Akrout, H., 2020. Investigations on biofilm forming bacteria involved in biocorrosion of carbon steel immerged in real wastewaters. International Biodeterioration & Biodegradation 150, 104960. are able to construct biofilm adjacent to carbon steel surface and leading to the biocorrosion and metal deterioration. The impact of wasterwaters’ indigenious bacteria on biocorrosion of carbon steel was evaluated under different pH values (3,7 and 9), two chloride concentrations (0.5 g/L and 1.5 g/L), and for two wastewaters. In tannery wastewaters (TWW) and under pH 3, Pseudomonas aeruginosa sp. (MN788665) and Enterobacter aerogenes sp. (MN788688) were able to establish an irreversible adhesion on the first stage of biofilm formation on the carbon steel surface due to hydrophobic behaviour of the bacteria. However, under the same pH, bacteria from industrial wastewaters (IWW) such us Brevundimonas diminuta sp. (MN788672) and Enterobacter aerogenes sp. (MN788689) promote the reversible adhesion followed by a continuous attachment and consequently a limited biofilm. Subsequently, in TWW and 0.5 g/L of chlorides, indigenious bacteria like Enterobacter aerogenes sp. (MN790737) and Raoultella ornithinolytica sp. promote an irreversible attachment of biofilm enhanced by their hydrophobic property contrarily to the bacteria isolated in the medium at chloride concentration of 1.5 g/L. In IWW, 1.5 g/L of chlorides the biofilm attachment is reversible and therefore its inhibition role is of little influence.El Diasty, W.S., El Beialy, S.Y., Mostafa, A.R., Abo Ghonaim, A.A., Peters, K.E., 2020. Chemometric differentiation of oil families and their potential source rocks in the Gulf of Suez. Natural Resources Research 29, 2063-2102. oil–oil and oil–source rock correlation study was carried out using chemometric methods applied to geochemical data for 123 Upper Cretaceous—Lower Miocene putative source rock and 46 crude oil samples from the Gulf of Suez Rift basin. The Gulf of Suez has many organic-rich intervals. The pre-rift source units, such as the Brown Limestone and Thebes formations, contain very good-to-excellent organic content, whereas the Miocene rocks are rated fair to good. HI and Tmax pyrolysis data indicate variable kerogen type and maturation histories where most of the analyzed samples occur along the Type II and Type II/III kerogen pathways from immature to the main stage of oil window with %Ro <?0.9. Carbon isotope ratios’ biomarker data for the bitumen samples indicate predominantly anoxic source rock depositional conditions with substantial algal/bacterial marine and a minor terrigenous organic matter. The Gulf of Suez oils exhibit a wide range of chemical composition from heavy-to-medium gravity and moderate-to-high sulfur content. These oils originated from carbonate/marl source rocks rich in lipids from phytoplankton/benthic algae and bacteria with less contribution of terrigenous organic debris, deposited under anoxic conditions with different thermal maturity histories equivalent to at least the early oil window. Chemometrics using 16 source-related biomarker and isotope ratios identifies six genetic families in the Gulf of Suez. The oil families share common characteristics where the precursor organic matter was deposited in a restricted marine environment with limited land-derived organic matter. The major factor that greatly modifies oil composition in the Gulf of Suez is thermal maturation. However, migration history and spatial and temporal organofacies’ variations of the presumed source rocks are also important. The overall geochemical similarity of the Gulf of Suez oils confirms the mixed nature of these fluids and suggests that no single source rock horizon is likely to have sourced the oil in this promising province. Based on oil–source correlation data and a decision tree chemometric model, the Brown Limestone, Esna, Thebes, and Nukhul formations are the effective source rocks for oil families III, IV, and V, whereas none of the source rock extracts has been assigned for Family I or VI oils.Evans, S.D., Hughes, I.V., Gehling, J.G., Droser, M.L., 2020. Discovery of the oldest bilaterian from the Ediacaran of South Australia. Proceedings of the National Academy of Sciences 117, 7845-7850.: The transition from simple, microscopic forms to the abundance of complex animal life that exists today is recorded within soft-bodied fossils of the Ediacara Biota (571 to 539 Ma). Perhaps most critically is the first appearance of bilaterians—animals with two openings and a through-gut—during this interval. Current understanding of the fossil record limits definitive evidence for Ediacaran bilaterians to trace fossils and enigmatic body fossils. Here, we describe the fossil Ikaria wariootia, one of the oldest bilaterians identified from South Australia. This organism is consistent with predictions based on modern animal phylogenetics that the last ancestor of all bilaterians was simple and small and represents a rare link between the Ediacaran and the subsequent record of animal life.Abstract: Analysis of modern animals and Ediacaran trace fossils predicts that the oldest bilaterians were simple and small. Such organisms would be difficult to recognize in the fossil record, but should have been part of the Ediacara Biota, the earliest preserved macroscopic, complex animal communities. Here, we describe Ikaria wariootia gen. et sp. nov. from the Ediacara Member, South Australia, a small, simple organism with anterior/posterior differentiation. We find that the size and morphology of Ikaria match predictions for the progenitor of the trace fossil Helminthoidichnites—indicative of mobility and sediment displacement. In the Ediacara Member, Helminthoidichnites occurs stratigraphically below classic Ediacara body fossils. Together, these suggest that Ikaria represents one of the oldest total group bilaterians identified from South Australia, with little deviation from the characters predicted for their last common ancestor. Further, these trace fossils persist into the Phanerozoic, providing a critical link between Ediacaran and Cambrian animals.Fagern?s, Z., García-Collado, M.I., Hendy, J., Hofman, C.A., Speller, C., Velsko, I., Warinner, C., 2020. A unified protocol for simultaneous extraction of DNA and proteins from archaeological dental calculus. Journal of Archaeological Science 118, 105135. materials are a finite resource, and efforts should be made to minimize destructive analyses. This can be achieved by using protocols combining extraction of several types of biomolecules or microparticles, which decreases the material needed for analyses while maximizing the information yield. Archaeological dental calculus is a source of several different types of biomolecules, as well as microfossils, and can tell us about the human host, microbiome, diet, and even occupational activities. Here, we present a unified protocol allowing for simultaneous extraction of DNA and proteins from a single sample of archaeological dental calculus. We evaluate the protocol on dental calculus from six individuals from a range of time periods and estimated preservation states, and compare it against previously published DNA-only and protein-only protocols. We find that most aspects of downstream analyses are unaltered by the unified protocol, although minor shifts in the recovered proteome can be detected, such as a slight loss of hydrophilic proteins. Total protein recovery depends on both the amount of starting material and choice of extraction protocol, whereas total DNA recovery is significantly reduced using the unified protocol (mean 43%). Nevertheless, total DNA recovery from dental calculus is generally very high, and we found no differences in DNA fragment characteristics or taxonomic profile between the protocols. In conclusion, the unified protocol allows for simultaneous extraction of two complementary lines of biomolecular evidence from archaeological dental calculus without compromising downstream results, thereby minimizing the need for destructive analysis of this finite resource.Fan, H., Nielsen, S.G., Owens, J.D., Auro, M., Shu, Y., Hardisty, D.S., Horner, T.J., Bowman, C.N., Young, S.A., Wen, H., 2020. Constraining oceanic oxygenation during the Shuram excursion in South China using thallium isotopes. Geobiology 18, 348-365. sediments record an unusual global carbon cycle perturbation that has been linked to widespread oceanic oxygenation, the Shuram negative C isotope excursion (NCIE). However, proxy‐based estimates of global ocean redox conditions during this event have been limited largely due to proxy specificity (e.g., euxinic sediments for Mo and U isotopes). Modern global seawater documents a homogenous Tl isotope composition (ε205Tl = ?6.0) due to significant manganese oxide burial, which is recorded in modern euxinic sediments. Here, we provide new data documenting that sediments deposited beneath reducing but a non‐sulfidic water column from the Santa Barbara Basin (ε205Tl = ?5.6 ± 0.1) also faithfully capture global seawater Tl isotope values. Thus, the proxy utilization of Tl isotopes can extend beyond strictly euxinic settings. Second, to better constrain the global redox conditions during the Shuram NCIE, we measured Tl isotopes of locally euxinic and ferruginous shales of the upper Doushantuo Formation, South China. The ε205Tl values of these shales exhibit a decreasing trend from ≈?3 to ≈?8, broadly coinciding with the onset of Shuram NCIE. There are ε205Tl values (?5.1 to ?7.8) during the main Shuram NCIE interval that approach values more negative than modern global seawater. These results suggest that manganese oxide burial was near or even greater than modern burial fluxes, which is likely linked to an expansion of oxic conditions. This ocean oxygenation may have been an important trigger for the Shuram NCIE and evolution of Ediacaran‐type biota. Subsequently, Tl isotopes show an increasing trend from the modern ocean value to values near the modern global inputs or even heavier (ε205Tl ≈ ?2.5 ~ 0.4), occurring prior to recovery from the NCIE. These records may suggest that there was a decrease in the extent of oxygenated conditions in the global oceans during the late stage of the Shuram NCIE.Fang, T., Zhang, Y., Yan, Y., Dai, C., Zhang, J., 2020. Molecular insight into the aggregation and dispersion behavior of modified nanoparticles. Journal of Petroleum Science and Engineering 191, 107193. microscopic behavior shown by the aggregation/dispersion of modified nanoparticles was investigated. In the present study, the definition of aggregation range and standard were indicated. Subsequently, the type of graft chains and molecular chain length were taken into consideration as the critical factors in diffusion process. The parameters of diffusion coefficient and radial distribution function were chosen to demonstrate that the fluctuation of aggregation/dispersion and the morphological changes of the graft chains can be used to evaluate the dispersibility of nanoparticles in a more objective way. In addition, when the salinity of NaCl was adjusted, the aggregation and fluctuation of nanoparticles show difference, with the emphasis laid on the significance attached to the brine and electric double layer for nanoparticles to aggregate and disperse. Moreover, our work provided a molecular-level understanding as to the interaction of nanoparticles in solution, and the results shed some light on the application of nanofluid.Faulk, S.P., Lora, J.M., Mitchell, J.L., Milly, P.C.D., 2020. Titan’s climate patterns and surface methane distribution due to the coupling of land hydrology and atmosphere. Nature Astronomy 4, 390-398. surfaces beyond Earth’s are impacted by surface hydrology, and exhibit fluvial and lacustrine features. Titan in particular harbours a rich hydroclimate replete with valley networks, lakes, seas and putative wetlands, all of which are pronounced in the lower-elevation polar regions. However, understanding of Titan’s global climate has heretofore neglected the hydraulic influence of Titan’s large-scale topography. Here we add a surface hydrology model to an existing Titan atmospheric model, and find that infiltration, groundmethane evaporation, and surface and subsurface flow are fundamental to simultaneously reproducing Titan’s observed surface liquid distribution and other aspects of its climate system. We propose that Titan’s climate features infiltration into unsaturated low- and mid-latitude highlands and surface or subsurface flow into high-latitude basins, producing the observed polar moist climes and equatorial deserts. This result implies that a potentially massive unobserved methane reservoir participates in Titan’s methane cycle. It also illustrates the importance of surface hydrology in Titan climate models, and by extension suggests the influence of surface hydrology in idealized models of other planetary climates, including the climates and palaeoclimates of Earth, Mars and exoplanets.Febrian, R., Ona, W.J., Araneda, J.F., Riegel, S.D., Bracher, P.J., 2020. Benchtop NMR spectroscopy of prebiotically-relevant peptide reactions enabled by salt-induced chemical shift dispersion. ACS Earth and Space Chemistry 4, 499-505. Article describes a method that increases the chemical shift dispersion of signals in proton nuclear magnetic resonance (1H NMR) spectra of peptides by the addition of salts to the sample. We demonstrate that the addition of potassium phosphate to aliquots of reactions of glycine peptides permits the measurement of their rate constants for hydrolysis by a 60 MHz benchtop instrument, which would otherwise be infeasible due to overlapping signals in the salt-free mixtures. The method is described in detail and validated by comparison to analysis on a 400 MHz spectrometer. The ability to use benchtop NMR spectroscopy to study reactions of simple peptides enables interested scientists at a broader array of institutions—not just those institutions capable of affording high-field NMR instruments—to participate in original research projects like those aimed at elucidating the chemistry that led to the origin of life on Earth.Feng, B., Shi, H., Xu, F., Hu, F., He, J., Yang, H., Ding, C., Chen, W., Yu, S., 2020. FTIR-assisted MALDI-TOF MS for the identification and typing of bacteria. Analytica Chimica Acta 1111, 75-82. MS is well-recognized for microbial identification and widely used in research and clinical fields due to its specificity, speed of analysis, and low cost of consumables. However, the classification or identification accuracy is poor for E. coli and Shigella. In addition, FTIR is a promising tool for bacterial typing. In this study, 14 strains of E. coli and 9 strains of Shigella were typed by both MALDI-TOF MS and FTIR techniques. Alternatively, a data fusion strategy using these two approaches was attempted to achieve better typing accuracy. Hierarchical clustering analysis (HCA) revealed that the typing accuracies for selected E. coli and Shigella from blood agar were 65.2%, 78.3%, and 100% for MALDI-TOF MS, FTIR, and FTIR combined with MALDI-TOF MS, respectively. Based on these results, a library constructed of the MS-IR fusion data was employed to identify individual bacteria at the strain level, and the library-based typing accuracies for 207 test spectra of sample strains from three different culture media yielded 97.6% accuracy for distinguishing between E. coli and Shigella at genus level. For species level and strain level, it yielded 95.2% and 92.3% typing accuracy, respectively. These results indicate that FTIR is a better technique for typing selected E. coli and Shigella than MALDI-TOF MS, and the accuracy is increased by combining the data from MALDI-TOF MS and FTIR spectroscopy. FTIR could be used to supplement MALDI-TOF MS for the identification and typing of taxonomic microorganisms.Feng, L., An, Y., Xu, J., Li, X., Jiang, B., Liao, Y., 2020. Biochemical evolution of dissolved organic matter during snow metamorphism across the ablation season for a glacier on the central Tibetan Plateau. Scientific Reports 10, 6123. metamorphism of snow (snowmelt process) has a potential influence on chemical and physical process occurring within it. This study carried out a detailed study on the variation of dissolved organic matter (DOM) in different stages of snowmelt in a typical mountain glacier located at Tibetan Plateau through collecting four different surface snow/ice categories, i.e., fresh snow, fine firn, coarse firn, and granular ice during May to October in 2015. The dissolved organic carbon (DOC) was observed by lost 44% from fresh snow to fine firn and enriched 129% from fine firn to granular ice, reflecting the dynamic variability in DOC concentration during snow metamorphism. The absorbance properties of each snow category are positively correlated with DOC concentration. The result of excitation emission matrix fluorescence with parallel factor analysis (EEM-PARAFAC) and Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) highlighted the domination of lipid- and protein-like compounds in glacial-derived DOM. The molecular composition of the DOM also exhibited a new N-containing molecular formula (CHON classes) that was enriched during snow metamorphism. This study suggests that snow metamorphism could induce a loss of DOM as well as enrich and modify the DOM.Feng, Z., Hao, F., Dong, D., Zhou, S., Wu, W., Xie, C., Cai, Y., Li, Z., 2020. Geochemical anomalies in the Lower Silurian shale gas from the Sichuan Basin, China: Insights from a Rayleigh-type fractionation model. Organic Geochemistry 142, 103981. verify recent single-well data from the Sichuan Basin, we analyzed the molecular and isotopic composition of late-mature Longmaxi shale gases from the southwestern portion of the Fuling block. The gases are highly enriched in methane (>96.1%) and have low C2+ hydrocarbon contents (<0.51%). The gases exhibit a reversal in carbon isotopes (δ13C3?<?δ13C2?<?δ13C1), and their δ13C1 values are abnormally enriched (i.e., equal to, or in some cases, more enriched than the associated kerogen). The helium component is typical of crustal genesis from the radiogenic decay of U and Th within the shale, which ranges from 145?ppm to 253?ppm, and its R/Ra ranges from 0.01 to 0.05. The δ15NN2 values range from ?5.2‰ to ?1.1‰, suggesting that the nitrogen was produced from the thermal de-ammoniation of organic matter. At extremely high thermal maturities and geothermal temperatures, shale gases with abnormally enriched δ13C1 values can best be explained using the model of Burruss and Laughrey (2010), which invokes a Rayleigh-type isotopic fractionation of ethane as it undergoes redox reactions to form methane and residual carbon in the late-stage (post-oil cracking) generation of methane. The variations in the distribution of δ13C1 and δ13C2 within the Fuling block imply that fluid-rock interactions related to the CO2 may have occurred, but not to a significant degree, and the cumulative effects of diffusion were also observed. Unraveling the geological processes that create the geochemical anomalies found in these Lower Silurian shale gas samples can provide valuable insight into the late-stage gas generation.Fernandes, S., Mazumdar, A., Peketi, A., Anand, S.S., Rengarajan, R., Jose, A., Manaskanya, A., Carvalho, M.A., Shetty, D., 2020. Sulfidization processes in seasonally hypoxic shelf sediments: A study off the West coast of India. Marine and Petroleum Geology 117, 104353. shelves are the major sites for organic carbon burial and sulfate reduction. Organic carbon degradation and sulfidization along continental shelves are expected to play a significant role in global carbon-sulfur-iron (C–S–Fe) cycles. Here we report sediment pore-water chemistry and iron-sulfur speciation in two short cores SSK-42/9 and 10 collected off Malvan from the seasonally hypoxic shelf region off the west coast of India (WCI) at water depths of 30 and 13 m respectively. Concentration profiles of pore-water SO42?, NH4+, DIC, ΣHS? and depth-integrated sulfate reduction rates (JSO4) suggest a variable influence of sedimentation rates, the composition of organic matter (marine and terrestrial) and anaerobic oxidation of methane (AOM) on the pore-fluid chemistry. Chromium reducible sulfur (CRS) and organic-bound sulfur (OBS) are the detectable solid-phase sulfur species in the studied sediment cores. Sulfur content and isotope ratios of chromium reducible sulfur (CRS) and organic-bound sulfur (OBS) phases produced via HS?/Sx2? pathways (sulfidization and sulfurization) show contrasting profiles in SSK42/9 and 10, apparently influenced by the availability of reactive iron, the relative significance of early and late diagenetic processes, source of OBS (detritus of marine origin and sulfurized organic molecules) and diffusion of ΣHS? produced via AOM across the SMTZ. The marked influence of AOM-driven sulfate reduction and the diffusion of isotopically enriched hydrogen sulfide across the sulfate-methane transition zone (SMTZ) is apparent from the δ34SCRS profiles in SSK-42/10. Sediment TOC/TS ratios recorded in this study are significantly less than that of average modern marine surface sediments (2.8:1) underlying oxygenated water and this is attributed to the enhanced sulfidization and burial of iron-sulfur minerals in the seasonally hypoxic regions. Since the inner shelf of WCI experiences seasonal alternation from normoxia to hypoxia which may have a profound influence on the benthic community structure, nature, and depth of bioturbation/bioirrigation, we propose that the impact of these processes need to be studied at a significantly higher resolution for better understanding C–S–Fe biogeochemical cycle.Fernández, I., 2020. Understanding the reactivity of polycyclic aromatic hydrocarbons and related compounds. Chemical Science 11, 3769-3779. perspective article summarizes recent applications of the combination of the activation strain model of reactivity and the energy decomposition analysis methods to the study of the reactivity of polycyclic aromatic hydrocarbons and related compounds such as cycloparaphenylenes, fullerenes and doped systems. To this end, we have selected representative examples to highlight the usefulness of this relatively novel computational approach to gain quantitative insight into the factors controlling the so far not fully understood reactivity of these species. Issues such as the influence of the size and curvature of the system on the reactivity are covered herein, which is crucial for the rational design of novel compounds with tuneable applications in different fields such as materials science or medicinal chemistry.Fernández, R., Gabaldón, T., 2020. Gene gain and loss across the metazoan tree of life. Nature Ecology & Evolution 4, 524-533. recent research has revealed high genomic complexity in the earliest-splitting animals and their ancestors, the macroevolutionary trends orchestrating gene repertoire evolution throughout the animal phyla remain poorly understood. We used a phylogenomic approach to interrogate genome evolution across all animal phyla. Our analysis uncovered a bimodal distribution of recruitment of orthologous genes, with most genes gained very ‘early’ (that is, at deep nodes) or very ‘late’, representing lineage-specific acquisitions. The emergence of animals was characterized by high values of gene birth and duplications. Deuterostomes, ecdysozoans and Xenacoelomorpha were characterized by no gene gain but rampant differential gene loss. Genes considered as animal hallmarks, such as Notch/Delta, were convergently duplicated in all phyla and at different evolutionary depths. Genes duplicated in all nodes from Metazoa to phylum-specific levels were enriched in functions related to the neural system, suggesting that this system has been continuously and independently reshaped throughout evolution across animals. Our results indicate that animal genomes evolved by unparalleled gene duplication followed by differential gene loss, and provide an atlas of gene repertoire evolution throughout the animal tree of life to navigate how, when and how often each gene in each genome was gained, duplicated or lost.Ferreira, P.S., Madeira, N.C.L., Folli, G.S., Rom?o, W., Filgueiras, P.R., Kuster, R.M., 2020. SAP fractions from light, medium and heavy oils: Correlation between chemical profile and stationary phases. Fuel 274, 117866. chemical composition of oil samples is fundamentally important for planning the recovery, transportation and refining processes of the oil industry. In this work, we examined how stationary phase affects the recovery of non-retained substances and the separation of saturated, aromatic and polar fractions from different density oils by column chromatography. We evaluated four stationary phases: silica gel, alumina, strong anion exchange (SAX) and C-18 silica gel, the latter being the only nonpolar one. The experiment was carried out in quintuplicate and the fractions obtained were analyzed by gas chromatography coupled with mass spectrometry and positive-ion mode electrospray ionization FT-ICR mass spectrometry (ESI(+)-FT-ICR MS). The influence of the stationary phase on the separation of the various classes of substances found in petroleum was observed by chemometrics. For saturated compounds, light and medium oils presented n-paraffins, iso-paraffins, naphthenes, terpanes and steranes, while heavy oil presented intense biodegradation, with a higher concentration of terpanes and steranes. When heavy oil was fractionated with C-18 silica gel, the presence of n-paraffins could also be observed. Alumina generated a saturated fraction, that was less contaminated with aromatics, and it showed a separation capacity similar to that of silica gel and SAX. For aromatics, all stationary phases generated fractions contaminated with saturated compounds, and polar fractions showed a greater presence of basic heteroaromatics compounds containing predominantly one nitrogen. A more reliable SAP separation of crude oil fractions depends on their density.Ferreira, V.H.C., Hantao, L.W., Poppi, R.J., 2020. Consumable-free comprehensive three-dimensional gas chromatography and PARAFAC for determination of allergens in perfumes. Chromatographia 83, 581-592. new consumable-free three-dimensional comprehensive gas chromatography (GC3-FID) was designed with modulators already known to comprehensive two-dimensional gas chromatography (GC?×?GC) users to showcase the opportunity of implementing GC3 systems. A hybrid interface composed of a thermal desorption modulator and a fast forward-flush differential flow modulator was used with modulation periods of 6 s and 300 ms, respectively. The determination of allergens in perfumes associated with chemometric tools, namely, parallel factor analysis (PARAFAC) was accomplished to demonstrate the validity of the proposed system. Evaluated allergens included already regulated ones in Brazil and Europe, such as geraniol and menthol, as well as potential allergens recommended in a 2011 opinion reported by the European Scientific Committee on Consumer Safety. Limits of detection were found to be suitable for current regulations, under 0.001% or 10 ?L L?1 for leave-on products. Considerations on the required acquisition rates, the limitations imposed by current modulator technology, the modulation periods used, and how they affect all three dimensions are thoroughly discussed. A GC3 coupled with mass spectrometry (GC3-MS) approach is also covered, as well as a comparison of the signal resolution/deconvolution with the increase of data dimensionality. Lastly, the union of GC3 and chemometric tools allowed for a solution that may be used for both qualitative and quantitative analyses.Fischer, R.A., Cottrell, E., Hauri, E., Lee, K.K.M., Le Voyer, M., 2020. The carbon content of Earth and its core. Proceedings of the National Academy of Sciences 117, 8743-8749.: Carbon is critical to life on Earth, climate regulation, and many geological processes. Despite its importance, the amount of carbon in the planet has been poorly understood due to uncertainty in the composition of Earth’s core, likely the largest reservoir of carbon. Here, we demonstrate that carbon becomes increasingly compatible in silicate compared to metal at the high pressures and temperatures at which Earth’s core formed. Therefore, carbon can only be present in the core in low abundances, although the core still likely holds the vast majority of the planet’s carbon.Abstract{ Earth’s core is likely the largest reservoir of carbon (C) in the planet, but its C abundance has been poorly constrained because measurements of carbon’s preference for core versus mantle materials at the pressures and temperatures of core formation are lacking. Using metal–silicate partitioning experiments in a laser-heated diamond anvil cell, we show that carbon becomes significantly less siderophile as pressures and temperatures increase to those expected in a deep magma ocean during formation of Earth’s core. Based on a multistage model of core formation, the core likely contains a maximum of 0.09(4) to 0.20(10) wt% C, making carbon a negligible contributor to the core’s composition and density. However, this accounts for ～80 to 90% of Earth’s overall carbon inventory, which totals 370(150) to 740(370) ppm. The bulk Earth’s carbon/sulfur ratio is best explained by the delivery of most of Earth’s volatiles from carbonaceous chondrite-like precursors.Fohlmeister, J., Voarintsoa, N.R.G., Lechleitner, F.A., Boyd, M., Brandtst?tter, S., Jacobson, M.J., L. Oster, J., 2020. Main controls on the stable carbon isotope composition of speleothems. Geochimica et Cosmochimica Acta 279, 67-87. climatic controls on the stable carbon isotopic composition (δ13C) of speleothem carbonate are less often discussed in the scientific literature in contrast to the frequently used stable oxygen isotopes. Various local processes influence speleothem δ13C values and confident and detailed interpretations of this proxy are often complex. A better understanding of speleothem δ13C values is critical to improving the amount of information that can be gained from existing and future records. This contribution aims to disentangle the various processes governing speleothem δ13C values and assess their relative importance. Using a large data set of previously published records we examine the spatial imprint of climate-related processes in speleothem δ13C values deposited post-1900 CE, a period during which global temperature and climate data is readily available. Additionally, we investigate the causes for differences in average δ13C values and growth rate under identical climatic conditions by analysing pairs of contemporaneously deposited speleothems from the same caves. This approach allows to focus on carbonate dissolution and fractionation processes during carbonate precipitation, which we evaluate using existing geochemical models. Our analysis of a large global data set of records reveals evidence for a temperature control, likely driven by vegetation and soil processes, on δ13C values in recently deposited speleothems. Moreover, data-model intercomparison shows that calcite precipitation occurring along water flow paths prior to reaching the top of the speleothem can explain the wide δ13C range observed for concurrently deposited samples from the same cave. We demonstrate that using the combined information of contemporaneously growing speleothems is a powerful tool to decipher controls on δ13C values, which facilitates a more detailed discussion of speleothem δ13C values as a proxy for climate conditions and local soil-karst processes.Folberth, J., Begemann, K., J?hren, O., Schwaninger, M., Othman, A., 2020. MS2 and LC libraries for untargeted metabolomics: Enhancing method development and identification confidence. Journal of Chromatography B 1145, 122105. part of the “omics” technologies in the life sciences, metabolomics is becoming increasingly important. In untargeted metabolomics, unambiguous metabolite identification and the inevitable coverage bias that comes with the selection of analytical conditions present major challenges. Reliable compound annotation is essential for translating metabolomics data into meaningful biological information. Here, we developed a fast and transferable method for generating in-house MS2 libraries to improve metabolite identification. Using the new method we established an in-house MS2 library that includes over 4,000 fragmentation spectra of 506 standard compounds for 6 different normalized collision energies (NCEs). Additionally, we generated a comprehensive liquid chromatography (LC) library by testing 57 different LC-MS conditions for 294 compounds. We used the library information to develop an untargeted metabolomics screen with maximum coverage of the metabolome that was successfully tested in a study of 360 human serum samples. The current work demonstrates a workflow for LC–MS/MS-based metabolomics, with enhanced metabolite identification confidence and the possibility to select suitable analysis conditions according to the specific research interest.France, C.A.M., Kaczkowski, R.A., Kavich, G.M., Epitropou, A., 2020. The effects of cyclododecane and subsequent removal on δ15N, δ13C, and δ18O values in collagen and bioapatite of a modern bone. Journal of Archaeological Science: Reports 31, 102367. consolidants to bone material in museum collections often is necessary to stabilize fragile specimens. However, this process can be difficult to reverse and may chemically alter the material, which may affect future biochemical analyses. Cyclododecane (CDD), a pliable solid that sublimates at room temperature, is a potential reversible alternative for temporary consolidation. This study examined the effects of CDD and Shell Cyclosol 53 (C53 – a solvent commonly used with CDD) on stable nitrogen, carbon, and oxygen isotope values in a modern whale rib. Different application methods (penetrating hot melt vs. surface heat spatula) and removal methods (low heat, ambient sublimation, and solvent) were tested in various combinations. The most effective method for removing CDD was low heat (65?°C); applying C53 also proved a viable option. All stable isotope values were unaffected by CDD application and solvent. No alteration was observed which suggests CDD does not affect the bone tissue structure, nor does it facilitate isotopic exchange or fractionation. This is an improvement over certain permanent consolidants which can alter bioapatite oxygen isotope values in particular. CDD is a viable temporary consolidant when further chemical analyses of bone tissue are desired.Fu, B., Balskus, E.P., 2020. Discovery of C–C bond-forming and bond-breaking radical enzymes: enabling transformations for metabolic engineering. Current Opinion in Biotechnology 65, 94-101. enzymes catalyze some of the most chemically challenging C–C bond-forming and bond-breaking reactions. Advances in DNA sequencing have accelerated the discovery of radical enzymes from microbes, including radical S-adenosylmethionine (rSAM) enzymes, glycyl radical enzymes (GREs), and diiron enzymes. These enzymes catalyze various reactions that yield products of industrial relevance (e.g. aromatics, hydrocarbons, and natural product derivatives), making their incorporation into engineered metabolic pathways enticing. Elucidating the mechanisms of radical enzymes that cleave and construct C–C bonds will enable further enzyme discovery and engineering efforts.Fujisaki, W., Fukami, Y., Matsui, Y., Sato, T., Sawaki, Y., Suzuki, K., 2020. Redox conditions and nitrogen cycling during the Triassic-Jurassic transition: A new perspective from the mid-Panthalassa. Earth-Science Reviews 204, 103173. determined redox-sensitive element concentrations along with δ15NTN values from the Triassic-Jurassic shales interbedded within deep-sea cherts at the Katsuyama section, SW Japan, to clarify the redox and related nitrogen cycle conditions in mid-Panthalassa during the TJB biotic crisis, focusing particularly on the linkages with CAMP volcanism. Slight enrichments of Mn and Mo across the TJB suggest a vertically expanded mid-Panthalassic OMZ above a well?oxygenated deep ocean. Moreover, high-resolution δ15NTN records during the Triassic-Jurassic transition exhibit a negative nitrogen isotope excursion (NNIE) just above the TJB. Relative to the previously reported negative carbon isotope excursion (NCIE) across the TJB, the NNIE can be divided into two intervals: negative interval 1 (NI-1) during the NCIE and NI-2 after the NCIE. The NNIE can be explained as an interval of nitrate-rich conditions, reflecting an oxic Panthalassic Ocean during the Triassic-Jurassic transition. Our geochemical dataset provides new insights into environmental perturbations in mid-Panthalassia during the TJB biotic crisis: (1) a vertically expanded OMZ and decreased primary productivity owing to global warming caused by CAMP volcanism across the TJB resulted in an increased nitrate concentration during the NI-1, and (2) eutrophic, nitrate-rich conditions developed in mid-Panthalassa during the NI-2 due to the enhanced continental weathering and deep-water upwelling. Significantly, our results are the first to demonstrate that the OMZs were expanded not only in the shallow-marine regions, but also in pelagic sites across the TJB, suggesting that the globally expanded OMZs can be regarded as a crucial driver for the TJB biotic crisis.Gao, C., Fernandez, V.I., Lee, K.S., Fenizia, S., Pohnert, G., Seymour, J.R., Raina, J.-B., Stocker, R., 2020. Single-cell bacterial transcription measurements reveal the importance of dimethylsulfoniopropionate (DMSP) hotspots in ocean sulfur cycling. Nature Communications 11, 1942. (DMSP) is a pivotal compound in marine biogeochemical cycles and a key chemical currency in microbial interactions. Marine bacteria transform DMSP via two competing pathways with considerably different biogeochemical implications: demethylation channels sulfur into the microbial food web, whereas cleavage releases sulfur into the atmosphere. Here, we present single-cell measurements of the expression of these two pathways using engineered fluorescent reporter strains of Ruegeria pomeroyi DSS-3, and find that external DMSP concentration dictates the relative expression of the two pathways. DMSP induces an upregulation of both pathways, but only at high concentrations (>1?μM for demethylation; >35?nM for cleavage), characteristic of microscale hotspots such as the vicinity of phytoplankton cells. Co-incubations between DMSP-producing microalgae and bacteria revealed an increase in cleavage pathway expression close to the microalgae’s surface. These results indicate that bacterial utilization of microscale DMSP hotspots is an important determinant of the fate of sulfur in the ocean.Garate, J., Lage, S., Martín-Saiz, L., Perez-Valle, A., Ochoa, B., Boyano, M.D., Fernández, R., Fernández, J.A., 2020. Influence of lipid fragmentation in the data analysis of imaging mass spectrometry experiments. Journal of the American Society for Mass Spectrometry 31, 517-526. mass spectrometry (IMS) is becoming an essential technique in lipidomics. Still, many questions remain open, precluding it from achieving its full potential. Among them, identification of species directly from the tissue is of paramount importance. However, it is not an easy task, due to the abundance and variety of lipid species, their numerous fragmentation pathways, and the formation of a significant number of adducts, both with the matrix and with the cations present in the tissue. Here, we explore the fragmentation pathways of 17 lipid classes, demonstrating that in-source fragmentation hampers identification of some lipid species. Then, we analyze what type of adducts each class is more prone to form. Finally, we use that information together with data from on-tissue MS/MS and MS3 to refine the peak assignment in a real experiment over sections of human nevi, to demonstrate that statistical analysis of the data is significantly more robust if unwanted peaks due to fragmentation, matrix, and other species that only introduce noise in the analysis are excluded.Garcia, A.K., McShea, H., Kolaczkowski, B., Ka?ar, B., 2020. Reconstructing the evolutionary history of nitrogenases: Evidence for ancestral molybdenum-cofactor utilization. Geobiology 18, 394-411. The nitrogenase metalloenzyme family, essential for supplying fixed nitrogen to the biosphere, is one of life's key biogeochemical innovations. The three forms of nitrogenase differ in their metal dependence, each binding either a FeMo-, FeV-, or FeFe-cofactor where the reduction of dinitrogen takes place. The history of nitrogenase metal dependence has been of particular interest due to the possible implication that ancient marine metal availabilities have significantly constrained nitrogenase evolution over geologic time. Here, we reconstructed the evolutionary history of nitrogenases, and combined phylogenetic reconstruction, ancestral sequence inference, and structural homology modeling to evaluate the potential metal dependence of ancient nitrogenases. We find that active-site sequence features can reliably distinguish extant Mo-nitrogenases from V- and Fe-nitrogenases and that inferred ancestral sequences at the deepest nodes of the phylogeny suggest these ancient proteins most resemble modern Mo-nitrogenases. Taxa representing early-branching nitrogenase lineages lack one or more biosynthetic nifE and nifN genes that both contribute to the assembly of the FeMo-cofactor in studied organisms, suggesting that early Mo-nitrogenases may have utilized an alternate and/or simplified pathway for cofactor biosynthesis. Our results underscore the profound impacts that protein-level innovations likely had on shaping global biogeochemical cycles throughout the Precambrian, in contrast to organism-level innovations that characterize the Phanerozoic Eon.Garrigues, J.-C., Cournac, M., Oswald, M., Ritter, N., Blanzat, M., Cassel, S., 2020. Analysis of complex mixtures of polyglycerol fatty esters using liquid chromatography and high-resolution mass spectrometry: retention, structural and relative composition study. Journal of Chromatography A 1616, 460792. esters (PGEs), produced by esterification of fatty acids on polyglycerols, were analysed by High Resolution Mass Spectrometry (HRMS), HPLC-MS and U-HPLC-MS. A structural study of PGEs in 4 samples synthesised by the Gattefossé company was carried out using an elemental analysis of HRMS spectra and modelling of all probable isomers and cyclic structures. The results were used to construct a structural database of all species present in the 4 samples. After an assessment of the selectivity of 5 reversed phase columns: Aeris Widepore XB-C8, 3.6?m, 2.1×150 mm (Phenomenex), Acquity CSH C18 1.7?m 2.1×50mm, Acquity CSH Phenyl-Hexyl 1.7?m 2.1×50 mm, Acquity CSH Fluoro-Phenyl 1.7?m 2.1×50mm (Waters Co.) and Kinetex F5 1.7?m 2.1×100mm (Phenomenex), HPLC-MS and U-HPLC-MS analyses were performed on an Aeris Widepore XB-C8 (Phenomenex) column (HPLC) and Acquity CSH Fluoro-Phenyl (Waters) column (U-HPLC) with aqueous formic acid /acetonitrile in gradient mode. The separation was optimised with 10 minutes (HPLC) and 5 minutes (U-HPLC) of gradient. The detection, performed on a QDA detector (Waters), produced extracted ion chromatograms (XICs) based on all adducts identified in the HRMS analysis. HPLC and U-HPLC analyses showed the different mono- and di-ester species and provided relative quantification of all identified constituents. The combined analyses of the HRMS, HPLC-MS and U-HPLC-MS results were used to compare the different PGE batches and quantify the molecular constituents according to their relative abundance, for these complex mixtures. With HPLC and U-HPLC analyses, using 2 different gradient times and 2 different selectivity columns, and comparing the retention factors and log P of the different species, it was possible to link structural identification and relative quantification of all PGEs identified in the samples.Gennadiev, A.N., Zhidkin, A.P., Koshovskii, T.S., 2020. Factors and trends in the formation of natural–technogenic associations of polycyclic aromatic hydrocarbons in the snow–soil system. Doklady Earth Sciences 490, 36-39. content of polycyclic aromatic hydrocarbons (PAHs) in soil and snow cover near the carbon black plants in Moscow, Omsk, and Samara regions was studied. The differences in the composition, bulk atmospheric deposition, and resources of PAHs in soils in key areas controlled by the production technology and the duration of the plant work were revealed. It was established that all key areas are characterized by lower modern delivery of PAHs in comparison with the activities of plants in the past. The highest amounts and the heaviest composition of PAHs were detected near a nonoperating plant, which previously had used an environmentally unfavorable tube technology. In all areas, the soils are characterized by a higher proportion of phenanthrene associations in relation to the snow; without account for phenanthrene in soils, the same PAHs dominate in the snow. The snow and soil PAH associations are the most similar near the operating plant.Georgiou, L., Dunmore, C.J., Bardo, A., Buck, L.T., Hublin, J.-J., Pahr, D.H., Stratford, D., Synek, A., Kivell, T.L., Skinner, M.M., 2020. Evidence for habitual climbing in a Pleistocene hominin in South Africa. Proceedings of the National Academy of Sciences 117, 8416-8423.: Here we present evidence of hominin locomotor behavior from the trabecular bone of the femur. We show evidence for habitual use of highly flexed hip postures, which could potentially indicate regular climbing in a South African hominin from Sterkfontein, which is either Paranthropus robustus or Homo. Second, we present evidence that Australopithecus africanus likely did not climb at the frequencies seen in extant nonhuman apes, and exhibits a modern, human-like pattern of loading at the hip joint. These results challenge the prevailing view of a single transition to bipedalism within the hominin clade by providing evidence of climbing in a more recent, non-Australopithecus South African hominin, and add to the increasing evidence for locomotor diversity in the hominin clade.Abstract: Bipedalism is a defining trait of the hominin lineage, associated with a transition from a more arboreal to a more terrestrial environment. While there is debate about when modern human-like bipedalism first appeared in hominins, all known South African hominins show morphological adaptations to bipedalism, suggesting that this was their predominant mode of locomotion. Here we present evidence that hominins preserved in the Sterkfontein Caves practiced two different locomotor repertoires. The trabecular structure of a proximal femur (StW 522) attributed to Australopithecus africanus exhibits a modern human-like bipedal locomotor pattern, while that of a geologically younger specimen (StW 311) attributed to either Homo sp. or Paranthropus robustus exhibits a pattern more similar to nonhuman apes, potentially suggesting regular bouts of both climbing and terrestrial bipedalism. Our results demonstrate distinct morphological differences, linked to behavioral differences between Australopithecus and later hominins in South Africa and contribute to the increasing evidence of locomotor diversity within the hominin clade.Gibbons, A., 2020. Lead pollution tracks the rise and fall of medieval kings. Science 368, 19. the Peak District of England, the picturesque village of Castleton nestles at the foot of a limestone outcrop crowned by a medieval castle. Today, hikers flock to the natural beauty of this region, home to the United Kingdom's first national park. But 800 years ago, the wild moors and wooded gorges were “covered in toxic lead pollution,” says archaeologist Chris Loveluck of the University of Nottingham. “The royal hunting forest near the castle was an industrial landscape.”Here, farmers mined and smelted so much lead that it left toxic traces in their bodies—and winds blew lead dust onto a glacier 1500 kilometers away in the Swiss Alps. Loveluck and his colleagues say the glacier preserves a detailed record of medieval lead production, which they have deciphered with a new method that can track deposition over a few weeks or even days.Lead tracks silver production because it is often found in the same ore, and the team found that the far-flung lead pollution was a sensitive barometer of the medieval English economy. As they report in a study published this week in Antiquity, lead spiked when kings took power, minted silver coins, and built cathedrals and castles. Levels plunged when plagues, wars, or other crises slowed mining and the air cleared. “This is extraordinary—lead levels correlate with the transition of kings,” says historian Joanna Story of the University of Leicester, who was not part of the study.Most people associate lead pollution with the Industrial Revolution, when lead became widely used in paints, pipes, and ceramics. But researchers have long known that the Romans also absorbed high levels of lead as they smelted silver and other ores. Recently, scientists have identified startling spikes of lead deposited in medieval times in Arctic ice cores and in lake sediments in Europe. A study last year suggested most of the pollution came from mines in Germany.The new study, however, points to England. In collaboration with Loveluck and historians at Harvard University, glaciologist Paul Mayewski and his team at the University of Maine, Orono, analyzed lead in an ice core drilled in 2013 in the Colle Gnifetti Glacier in the Swiss Alps. The 72-meter-long core preserves more than 2000 years of fallout from pollution, volcanoes, and Saharan dust storms. To decipher this record at the highest possible resolution, the team used a laser to carve 120-micron slivers of ice, each representing just a few days or weeks of snowfall, along the length of the core. They analyzed the samples—some 50,000 from each meter of the core—for about a dozen elements, including lead.The ice core data reveal the scale of regional pollution, showing dramatic lead spikes between 1170 and 1219 C.E.—“the highest levels of lead pollution before modernity,” says historian Alexander More, of Harvard and Long Island University, Brooklyn. Lead levels matched those recorded in 1890, at the height of the Industrial Revolution. (Lead in the core peaked in the 1970s, spurred by leaded gasoline.)To find the source of the medieval spikes, the team modeled how winds carry pollution. They found that during summer, lead-laced winds blew to the glacier from the northwest—from England. Summer, between spring and fall harvests, was also when Peak District farmers mined the most lead. “You have women and children breaking the rocks and smelting the ore in Castleton, and the lead is getting picked up and transported over the western Alps,” says historian Ann Carmichael of Indiana University, Bloomington.The ice core data spurred Loveluck to groundtruth the method with the English Pipe rolls, historic scrolls that record annual taxes paid by miners for cartloads of lead. At a 2018 workshop at Harvard, the geoscientists and historians found they could match lead pollution in the Swiss ice core, taxes paid, and events in English history. For example, when Mayewski showed on a graph that lead pollution plummeted in 1170, Loveluck and Harvard historian Michael McCormick immediately knew why: “1170 was the year that Henry II's assassins killed the archbishop of Canterbury [Thomas Becket] and Henry was excommunicated,” Loveluck says. “Nobody paid any taxes.” Mining stopped.Ten years later, lead pollution peaked. That's when Henry II had finally made up with the pope and “began to bankroll the rebuilding of Cistercian abbeys,” Loveluck says. “He has massive lead orders” for building roofs, gutters, and cisterns, which are reflected in taxes on mines in the Peak District and at Carlisle in Northern England.Lead in the core surged again in 1193, when Richard I (the “Lionheart”) was imprisoned in Germany by the Holy Roman Emperor Henry VI, who demanded a ransom. “There appears to be a very concerted effort to pay the ransom,” McCormick says, which gave a turbo boost to lead and silver mining.But Richard I left his successor and brother, John I, a depleted treasury. John lost Normandy in a war with France and was perceived as weak. Emboldened, his barons revolted in 1215, when John was forced to sign the Magna Carta, giving the church and barons more rights and reducing John's ability to raise taxes, McCormick says. John died in 1216 and during the rocky transition to his son, Henry III, coins were not minted and mining stopped. Lead levels in the core plummeted.For miners and their families, economic good times—when lead production spiked—may have also spurred devastating health effects, says Loveluck, who is part of an ongoing study of Castleton skeletons.Other nations' mines may also have contributed to the surges in the ice core, cautions geochemist Paolo Gabrielli of Ohio State University, Columbus. And snow hydrologist Joe McConnell of the Desert Research Institute, part of the rival group that proposed German mines as the source of high lead levels in Arctic ice cores, questions the precision of the new study. He notes that much of the snow that drops on Swiss glaciers is blown away, leaving an incomplete record in the ice.One way to settle the debate would be to check mining records: McCormick says silver and lead mining peaked in one German region before this period. Researchers could also study whether lead from English and German mines has distinctive isotopic signatures; if so, isotopes in the ice record could settle which region polluted most. Meanwhile, other teams are analyzing ice cores elsewhere in the Alps for lead. “We've got to do this work fast, before all of these glaciers melt,” Carmichael says.Girard, F., Sarrazin, J., Olu, K., 2020. Impacts of an eruption on cold-seep microbial and faunal dynamics at a mud volcano. Frontiers in Marine Science 7, 241. doi: 10.3389/fmars.2020.00241. seeps are widespread in the deep sea and, like other chemosynthesis-based ecosystems, often host high faunal biomass. Temporal changes at seeps have been inferred by comparing communities at different successional stages; nonetheless, temporal studies in seep ecosystems are rare. Using data collected as part of a benthic observatory, we characterized intra-annual microbial and faunal dynamics in a microbial mat habitat on the H?kon Mosby mud volcano (1256 m depth; Barents Sea), and evaluated the effects of a mud eruption on the biota. Video sequences recorded twice daily for 4.5 months with an autonomous imaging module were analyzed to quantify changes in microbial mat cover and megafaunal density and behavior. In addition, time series data for pressure, bottom currents, and seabed temperature were analyzed to characterize environmental changes. Of the five taxa observed on the video footage, the zoarcid Lycodes squamiventer, the pycnogonid Nymphon macronyx, and the skate Amblyraja hyperborea were the most common. Zoarcids made frequent incursions on microbial mats, but were more often documented on the adjacent sediments. The cyclic behavior of common trends identified between microbial mat cover, zoarcid densities, and abiotic variables using dynamic factor analysis suggested that seep ecosystem dynamics at the H?kon Mosby mud volcano may be modulated by tides and the activity of the volcano. Moreover, the eruption that occurred about 2 months after the start of the study had a significant impact on faunal densities, microbial activity, and environmental variables. The eruption was preceded by a steady increase in seabed temperatures, density of small holes (indicative of gas emissions), and microbial mat cover. It was followed by 3- and 5-fold increase in zoarcid and pycnogonid densities, respectively. To our knowledge, this study is the first to analyze intra-annual temporal data in a cold-seep ecosystem and to present data on the effects of a mud eruption on seep microbial and faunal dynamics. Overall, our results provide the first insight into ecosystem dynamics at a high-latitude cold seep and highlight the need to collect high-resolution temporal data to evaluate seep communities’ response to a warming Arctic and their potential role in mitigating methane emissions.Glodowska, M., Stopelli, E., Schneider, M., Lightfoot, A., Rathi, B., Straub, D., Patzner, M., Duyen, V.T., AdvectAs Team Members, Berg, M., Kleindienst, S., Kappler, A., 2020. Role of in situ natural organic matter in mobilizing As during microbial reduction of FeIII-mineral-bearing aquifer sediments from Hanoi (Vietnam). Environmental Science & Technology 54, 4149-4159. organic matter (NOM) can contribute to arsenic (As) mobilization as an electron donor for microbially-mediated reductive dissolution of As-bearing Fe(III) (oxyhydr)oxides. However, to investigate this process, instead of using NOM, most laboratory studies used simple fatty acids or sugars, often at relatively high concentrations. To investigate the role of relevant C sources, we therefore extracted in situ NOM from the upper aquitard (clayey silt) and lower sandy aquifer sediments in Van Phuc (Hanoi area, Vietnam), characterized its composition, and used 100-day microcosm experiments to determine the effect of in situ OM on Fe(III) mineral reduction, As mobilization, and microbial community composition. We found that OM extracted from the clayey silt (OMC) aquitard resembles young, not fully degraded plant-related material, while OM from the sandy sediments (OMS) is more bioavailable and related to microbial biomass. Although all microcosms were amended with the same amount of C (12 mg C/L), the extent of Fe(III) reduction after 100 days was the highest with acetate/lactate (43 ± 3.5% of total Fe present in the sediments) followed by OMS (28 ± 0.3%) and OMC (19 ± 0.8%). Initial Fe(III) reduction rates were also higher with acetate/lactate (0.53 mg Fe(II) in 6 days) than with OMS and OMC (0.18 and 0.08 mg Fe(II) in 6 days, respectively). Although initially more dissolved As was detected in the acetate/lactate setups, after 100 days, higher concentrations of As (8.3 ± 0.3 and 8.8 ± 0.8 μg As/L) were reached in OMC and OMS, respectively, compared to acetate/lactate-amended setups (6.3 ± 0.7 μg As/L). 16S rRNA amplicon sequence analyses revealed that acetate/lactate mainly enriched Geobacter, while in situ OM supported growth and activity of a more diverse microbial community. Our results suggest that although the in situ NOM is less efficient in stimulating microbial Fe(III) reduction than highly bioavailable acetate/lactate, it ultimately has the potential to mobilize the same amount or even more As.Goffredi, S.K., Tilic, E., Mullin, S.W., Dawson, K.S., Keller, A., Lee, R.W., Wu, F., Levin, L.A., Rouse, G.W., Cordes, E.E., Orphan, V.J., 2020. Methanotrophic bacterial symbionts fuel dense populations of deep-sea feather duster worms (Sabellida, Annelida) and extend the spatial influence of methane seepage. Science Advances 6, eaay8562. cold seeps are dynamic sources of methane release and unique habitats supporting ocean biodiversity and productivity. Here, we describe newly discovered animal-bacterial symbioses fueled by methane, between two species of annelid (a serpulid Laminatubus and sabellid Bispira) and distinct aerobic methane-oxidizing bacteria belonging to the Methylococcales, localized to the host respiratory crown. Worm tissue δ13C of ?44 to ?58‰ are consistent with methane-fueled nutrition for both species, and shipboard stable isotope labeling experiments revealed active assimilation of 13C-labeled methane into animal biomass, which occurs via the engulfment of methanotrophic bacteria across the crown epidermal surface. These worms represent a new addition to the few animals known to intimately associate with methane-oxidizing bacteria and may further explain their enigmatic mass occurrence at 150–million year–old fossil seeps. High-resolution seafloor surveys document significant coverage by these symbioses, beyond typical obligate seep fauna. These findings uncover novel consumers of methane in the deep sea and, by expanding the known spatial extent of methane seeps, may have important implications for deep-sea conservation.Goh, S.X.L., Chong, B.H.D., Lee, H.K., 2020. Fully automated water sampling—surfactant-enhanced membrane bag liquid-phase microextraction—ultrahigh performance liquid chromatography–mass spectrometry. Analytical Chemistry 92, 5362-5369. fully automated integrated analytical platform that included continuous water sampling, sample preparation (extraction), and analysis for the determination of nine glucocorticoids was developed. A peristaltic pump was employed to deliver the water sample automatically. The subsequent sample preparation and analytical processes were also fully automated with the use of a commercial autosampler unit coupled to an ultrahigh performance liquid chromatography–tandem mass spectrometric system. The sample preparation step involved membrane bag liquid-phase microextraction in which a synergistic mixture of n-octanol enhanced with surfactant sodium dodecyl sulfate (SDS) (0.10% in n-octanol) was applied as the extractant phase. Addition of SDS helped to improve the extraction, increasing enrichment factors (EFs) by severalfold compared with the use of n-octanol only as extractant solvent. Various parameters to improve extraction efficiency were evaluated. They included percentage of surfactant used, sample pH, agitation rate, extraction duration, salting out effect, extraction temperature, and flow rate for sample introduction. Under the most favorable conditions, enrichment factors of between 32 and 189 were attained with relative standard deviations of <8%. The limits of detection for the glucocorticoids were between 0.03 and 0.17 ng/mL, whereas the limits of quantitation were between 0.09 and 0.52 ng/mL, indicating the good sensitivity of the method. The method was successfully applied to determine glucocorticoids in industrial canal water. This work also provided some insights on the potential of on-site sampling and real-time monitoring of contaminants in environmental waters.Gorbalenya, A.E., Krupovic, M., Mushegian, A., Kropinski, A.M., Siddell, S.G., Varsani, A., Adams, M.J., Davison, A.J., Dutilh, B.E., Harrach, B., Harrison, R.L., Junglen, S., King, A.M.Q., Knowles, N.J., Lefkowitz, E.J., Nibert, M.L., Rubino, L., Sabanadzovic, S., Sanfa?on, H., Simmonds, P., Walker, P.J., Zerbini, F.M., Kuhn, J.H., International Committee on Taxonomy of Viruses Executive Committee, 2020. The new scope of virus taxonomy: partitioning the virosphere into 15 hierarchical ranks. Nature Microbiology 5, 668-674. taxonomy emerged as a discipline in the middle of the twentieth century. Traditionally, classification by virus taxonomists has been focussed on the grouping of relatively closely related viruses. However, during the past few years, the International Committee on Taxonomy of Viruses (ICTV) has recognized that the taxonomy it develops can be usefully extended to include the basal evolutionary relationships among distantly related viruses. Consequently, the ICTV has changed its Code to allow a 15-rank classification hierarchy that closely aligns with the Linnaean taxonomic system and may accommodate the entire spectrum of genetic divergence in the virosphere. The current taxonomies of three human pathogens, Ebola virus, severe acute respiratory syndrome coronavirus and herpes simplex virus 1 are used to illustrate the impact of the expanded rank structure. This new rank hierarchy of virus taxonomy will stimulate further research on virus origins and evolution, and vice versa, and could promote crosstalk with the taxonomies of cellular organisms.Gorchov Negron, A.M., Kort, E.A., Conley, S.A., Smith, M.L., 2020. Airborne assessment of methane emissions from offshore platforms in the U.S. Gulf of Mexico. Environmental Science & Technology 54, 5112-5120. (CH4) emissions from oil and gas activities are large and poorly quantified, with onshore studies showing systematic inventory underestimates. We present aircraft measurements of CH4 emissions from offshore oil and gas platforms collected over the U.S. Gulf of Mexico in January 2018. Flights sampled individual facilities as well as regions of 5–70 facilities. We combine facility-level samples, production data, and inventory estimates to generate an aerial measurement-based inventory of CH4 emissions for the U.S. Gulf of Mexico. We compare our inventory and the Environmental Protection Agency Greenhouse Gas Inventory (GHGI) with regional airborne estimates. The new inventory and regional airborne estimates are consistent with the GHGI in deep water but appear higher for shallow water. For the full U.S. Gulf of Mexico our inventory estimates total emissions of 0.53 Tg CH4/yr [0.40–0.71 Tg CH4/yr, 95% CI] and corresponds to a loss rate of 2.9% [2.2–3.8%] of natural gas production. Our estimate is a factor of 2 higher than the GHGI updated with 2018 platform counts. We attribute this disagreement to incomplete platform counts and emission factors that both underestimate emissions for shallow water platforms and do not account for disproportionately high emissions from large shallow water facilities.Gr?dinaru, M., Laz?r, I., Ducea, M.N., Petrescu, L., 2020. Microaerophilic Fe-oxidizing micro-organisms in Middle Jurassic ferruginous stromatolites and the paleoenvironmental context of their formation (Southern Carpathians, Romania). Geobiology 18, 366-393. stromatolites occur associated with Middle Jurassic condensed deposits in several Tethyan and peri‐Tethyan areas. The studied ferruginous stromatolites occurring in the Middle Jurassic condensed deposits of Southern Carpathians (Romania) preserve morphological, geochemical, and mineralogical data that suggest microbial iron oxidation. Based on their macrofabrics and accretion patterns, we classified stromatolites: (1) Ferruginous microstromatolites associated with hardground surfaces and forming the cortex of the macro‐oncoids and (2) Domical ferruginous stromatolites developed within the Ammonitico Rosso‐type succession disposed above the ferruginous microstromatolites (type 1). Petrographic and scanning electron microscope (SEM) examinations reveal that different types of filamentous micro‐organisms were the significant framework builders of the ferruginous stromatolitic laminae. The studied stromatolites yield a large range of δ56Fe values, from ?0.75‰ to +0.66‰ with predominantly positive values indicating the prevalence of partial ferrous iron oxidation. The lowest negative δ56Fe values (up to ?0.75‰) are present only in domical ferruginous stromatolites samples and point to initial iron mobilization where the Fe(II) was produced by dissimilatory Fe(III) reduction of ferric oxides by Fe(III)‐reducing bacteria. Rare‐earth elements and yttrium (REE + Y) are used to decipher the nature of the seawater during the formation of the ferruginous stromatolites. Cerium anomalies display moderate to small negative values for the ferruginous microstromatolites, indicating weakly oxygenated conditions compatible with slowly reducing environments, in contrast to the domical ferruginous stromatolites that show moderate positive Ce anomalies suggesting that they formed in deeper, anoxic–suboxic waters. The positive Eu anomalies from the studied samples suggest a diffuse hydrothermal input on the seawater during the Middle Jurassic on the sites of ferruginous stromatolite accretion. This study presents the first interpretation of REE + Y in the Middle Jurassic ferruginous stromatolites of Southern Carpathians, Romania.Grün, R., Pike, A., McDermott, F., Eggins, S., Mortimer, G., Aubert, M., Kinsley, L., Joannes-Boyau, R., Rumsey, M., Denys, C., Brink, J., Clark, T., Stringer, C., 2020. Dating the skull from Broken Hill, Zambia, and its position in human evolution. Nature 580, 372-375. cranium from Broken Hill (Kabwe) was recovered from cave deposits in 1921, during metal ore mining in what is now Zambia. It is one of the best-preserved skulls of a fossil hominin, and was initially designated as the type specimen of Homo rhodesiensis, but recently it has often been included in the taxon Homo heidelbergensis. However, the original site has since been completely quarried away, and—although the cranium is often estimated to be around 500 thousand years old—its unsystematic recovery impedes its accurate dating and placement in human evolution. Here we carried out analyses directly on the skull and found a best age estimate of 299 ± 25 thousand years (mean ± 2σ). The result suggests that later Middle Pleistocene Africa contained multiple contemporaneous hominin lineages (that is, Homo sapiens, H. heidelbergensis/H. rhodesiensis and Homo naledi), similar to Eurasia, where Homo neanderthalensis, the Denisovans, Homo floresiensis, Homo luzonensis and perhaps also Homo heidelbergensis and Homo erectus were found contemporaneously. The age estimate also raises further questions about the mode of evolution of H. sapiens in Africa and whether H. heidelbergensis/H. rhodesiensis was a direct ancestor of our species.Gu, Y., Ding, W., Tian, Q., Xu, S., Zhang, W., Zhang, B., Jiao, B., 2020. Developmental characteristics and dominant factors of natural fractures in lower Silurian marine organic-rich shale reservoirs: A case study of the Longmaxi formation in the Fenggang block, southern China. Journal of Petroleum Science and Engineering 192, 107277. fractures are an important storage space and main seepage channel of shale gas reservoirs, controlling the permeability of shale gas reservoirs and the migration, enrichment, preservation conditions and single-well productivity of shale gas. The successful production of shale gas has shown that the development of natural fractures in shale is beneficial, and a high degree of natural fracture development can allow a large-scale fracture network to form in the process of hydraulic fracturing, which can effectively improve the shale reservoir conditions. The development of fractures in shale reservoirs not only effectively improves the permeability of shale reservoirs but also increases the gas content, improving the productivity of shale reservoirs. Therefore, the degree of shale fracture development is the key to the production of shale gas reservoirs. Through the outcrop, shale core, thin section and scanning electron microscopy observations of the Longmaxi shale in the Fenggang block of Guizhou Province and the experimental data analysis of the corresponding samples, the fracture characteristics are statistically analyzed, and the fracture development characteristics and dominant factors are discussed in depth. The study area is located in the complex tectonic area of southern China, which experienced a strong tectonic deformation and a high degree of fracture development. The multiscale characterization of Longmaxi shale fractures indicates the following: the fractures observable in the field are mainly regional structural fractures, fold-related fractures, fault-related fractures and bedding fractures; additionally, the statistical analysis of core fractures shows that the structural fractures, including high-angle shear fractures, tension-shear fractures, and low-angle slip fractures are dominant and that most of them are filled with calcite; the micro-fractures are mainly intragranular fractures and intergranular fractures, and the fracture aperture is 0.01–2?μm. The degree of fracture development is controlled by structural factors, lithology, mineral composition and content, TOC, rock mechanical properties, paleoenvironment and diagenesis, and the structural factors are the most influential. The gentle transition zone of a fold limb is a favorable position for shale gas structure preservation. Fractures significantly impact the formation of seepage channels and storage space and the connection of isolated micro-pores, so the degree of fracture development has a positive relationship with the total and analytical gas contents.Guijarro-Clarke, C., Holland, P.W.H., Paps, J., 2020. Widespread patterns of gene loss in the evolution of the animal kingdom. Nature Ecology & Evolution 4, 519-523. animal kingdom shows an astonishing diversity, the product of over 550 million years of animal evolution. The current wealth of genome sequence data offers an opportunity to better understand the genomic basis of this diversity. Here we analyse a sampling of 102 whole genomes including >2.6 million protein sequences. We infer major genomic patterns associated with the variety of animal forms from the superphylum to phylum level. We show that a remarkable amount of gene loss occurred during the evolution of two major groups of bilaterian animals, Ecdysozoa and Deuterostomia, and further loss in several deuterostome lineages. Deuterostomes and protostomes also show large genome novelties. At the phylum level, flatworms, nematodes and tardigrades show the largest reduction of gene complement, alongside gene novelty. These findings paint a picture of evolution in the animal kingdom in which reductive evolution at the protein-coding level played a major role in shaping genome composition.Guilbaud, R., Poulton, S.W., Thompson, J., Husband, K.F., Zhu, M., Zhou, Y., Shields, G.A., Lenton, T.M., 2020. Phosphorus-limited conditions in the early Neoproterozoic ocean maintained low levels of atmospheric oxygen. Nature Geoscience 13, 296-301. redox chemistry of anoxic continental margin settings evolved from widespread sulfide-containing (euxinic) conditions to a global ferruginous (iron-containing) state in the early Neoproterozoic era (from ~1 to 0.8 billion years ago). Ocean redox chemistry exerts a strong control on the biogeochemical cycling of phosphorus, a limiting nutrient, and hence on primary production, but the response of the phosphorus cycle to this major ocean redox transition has not been investigated. Here, we use a geochemical speciation technique to investigate the phase partitioning of phosphorus in an open marine, early Neoproterozoic succession from the Huainan Basin, North China. We find that effective removal of bioavailable phosphorus in association with iron minerals in a globally ferruginous ocean resulted in oligotrophic (nutrient limited) conditions, and hence a probable global decrease in primary production, organic carbon burial and, subsequently, oxygen production. Nevertheless, phosphorus availability and organic carbon burial were sufficient to maintain an oxidizing atmosphere. These data imply substantial nutrient-driven variability in atmospheric oxygen levels through the Proterozoic, rather than the stable levels commonly invoked.Güle?, F., Meredith, W., Snape, C.E., 2020. Progress in the CO2 capture technologies for fluid catalytic cracking (FCC) units—a review. Frontiers in Energy Research 8, 62. doi: 10.3389/fenrg.2020.00062. industries including cement, iron and steel, oil refining, and petrochemicals are collectively responsible for about 22% of global CO2 emissions. Among these industries, oil refineries account for 4–6%, of which typically 25–35% arise from the regenerators in Fluid Catalytic Cracking (FCC) units. This article reviews the progress in applying CO2 capture technologies to FCC units. Post combustion and oxyfuel combustion have been investigated to mitigate CO2 emissions in FCC and, more recently, Chemical Looping Combustion (CLC) has received attention. Post combustion capture can readily be deployed to the flue gas in FCC units and oxyfuel combustion, which requires air separation has been investigated in a pilot-scale unit by Petrobras (Brazil). However, in comparison, CLC offers considerably lower energy penalties. The applicability of CLC for FCC has also been experimentally investigated at a lab-scale. As a result, the studies demonstrated highly promising CO2 capture capacities for FCC with the application of post combustion (85–90%), oxyfuel combustion (90–100%) and CLC (90–96%). Therefore, the method having lowest energy penalty and CO2 avoided cost is highly important for the next generation of FCC units to optimize CO2 capture. The energy penalty was calculated as 3.1–4.2 GJ/t CO2 with an avoiding cost of 75–110 €/t CO2 for the application of post combustion capture to FCC. However, the application of oxyfuel combustion provided lower energy penalty of 1.8–2.5 GJ/t CO2, and lower CO2 avoided cost of 55–85 €/t CO2. More recently, lab-scale experiments demonstrated that the application of CLC to FCC demonstrate significant progress with an indicative much lower energy penalty of ca. 0.2 GJ/t CO2.Guo, Z., Li, J., Tian, J., Zeng, X., Xu, X., Wang, R., Zhao, F., 2020. Main factors controlling thermogenic gas accumulation in the Qaidam Basin of western China. Energy & Fuels 34, 4017-4030. gas resources in the Qaidam Basin are abundant and of various types. On the basis of the natural gas carbon isotope distribution characteristics, the western Qaidam Basin mainly comprises oil-type gas, whereas the northern margin of the basin primarily contains coal-type gas. These types are of thermal origin. Thermogenic natural gas has the same characteristics in terms of distribution regularities and main controlling factors of reservoir accumulation. In this study, geochemical, geophysical, geological, and basin simulations were comprehensively completed to investigate the thermogenic gas distribution and the main controlling factors of its accumulation in the Qaidam Basin. The distribution of oil and gas accumulation zones based on source rock maturity maps indicates that the oil is distributed in and near low-maturity to mature (0.5% < Ro < 0.8%) source rock areas. Meanwhile, natural gas is distributed in mature (0.8% < Ro < 1.3%) to highly mature (Ro > 1.3%) source rock areas. The areas wherein oil and gas coexist are near and in mature (0.8% < Ro < 1.3%) source rock areas. Thus, the tectonic evolutionary history, paleostructural map, source–reservoir–cap assemblage, and gas accumulation model were analyzed. The results indicated that the main controlling factors for natural gas reservoir formation are as follows: mature source rocks control the horizontal distribution of natural gas, ancient uplifts or slopes control natural gas migration direction, faults and an unconformity control gas migration channels, and high-quality reservoirs regulate the reserve scale. Moreover, locating favorable reservoirs can be the subsequent step in natural gas exploration near and in mature to highly mature source rock areas along paleouplifts and ancient slopes with deep faults. Therefore, this study is significant when conducting natural gas exploration in this area.Gusa, A.V., Tomani, A., Zhang, Z., Vidic, R.D., 2020. Sulfate precipitation in produced water from Marcellus Shale for the control of naturally occurring radioactive material. Water Research 177, 115765. water (PW) generated during unconventional oil and gas extraction is characterized by very high total dissolved solids (TDS) that mainly consist of alkali and alkaline earth metals. Dominant PW management strategy (i.e., injection in Class II disposal wells) is scrutinized by regulatory agencies, and the public and PW treatment that enables high water and salt recovery (i.e., evaporation/crystallization) is being considered as an alternative. Produced water generated in the Marcellus Shale play also contains very high levels of Naturally Occurring Radioactive Material (NORM) in the form of Ra-226 and Ra-228, which is one of the key impediments for the recovery of high-quality salts. This study was designed to evaluate the efficiency of Ra-226 removal using co- and post-precipitation with barium sulfate to enable advanced PW treatment processes. High Sr/Ba molar ratios in PW lead to relatively low Ba2+ and Ra2+ removal, and Ba2+ concentration adjustment is necessary to achieve required treatment standards (i.e., [Ba2+] < 10 mg/L and [Ra2+] < 50 pCi/L). Seeding the reactor with barium sulfate enhanced Ba2+ and Ra2+ removal through induced heterogeneous precipitation of barite. However, it was necessary to simultaneously adjust the Sr/Ba ratio and barite level to achieve treatment requirements while maintaining reasonable detention time in the reactor (i.e., <30 min) and minimizing sludge production. Experimental and modeling results revealed that low Ba2+ and Ra2+ effluent concentrations, with minimized sludge production, can be achieved only when the barium sulfate saturation index was above 4.7, Sr/Ba molar ratio was below 2 and there was at least 25 g/L of barite “seed” in the system. This study provides useful guidelines for centralized wastewater treatment facilities in shale plays and serves to optimize pretreatment of produced water to enable recovery of valuable resources (i.e., clean water and usable salts).Guzmán-Osorio, F.J., Adams, R.H., Domínguez-Rodríguez, V.I., Lobato-García, C.E., Guerrero-Pe?a, A., Barajas-Hernández, J.R., Baltierra-Trejo, E., 2020. Alternative method for determining API degrees of petroleum in contaminated soil by FTIR. Egyptian Journal of Petroleum 29, 39-44. method was developed to determine °API from the relative abundance of polar and aliphatic functional groups as measured by FTIR. Twenty-two samples of petroleum were collected from the southern region of Mexico and analyzed by FTIR using an Attenuated Total Reflectance (ATR) accessory. API gravity was run in parallel using the convention hydrometer method (ASTM D6822-12b). Variables were analyzed for principal components and a minimum of squares regression. API gravity of the petroleum used was between ?8.8 and 41.5. For correlation, an index of the relative abundance of polar functional groups vs. saturates was developed. Data from calibration gave an R2?=?0.9632 and a standard error of 0.0129, with an absolute error of 0.0104. During the validation (with petroleum from contaminated sites), the results gave an R2?=?0.9024, with a standard error estimated at 0.0307 and an absolute mean error of 0.0199. Thus, the determination of API degrees of petroleum extracted from contaminated soil was shown to be viable using FTIR-ATR. The algorithm was developed to fit well for the whole range of crudes, from extra heavy (<10 °API) to super light (>39 °API) crudes. This method is simple, quick, does not require extensive sample preparation, uses very small sample proportions (<1?g) and produces only a minimum of waste as compared to the conventional (hydrometer) method.Guzman, M., Szopa, C., Freissinet, C., Buch, A., Stalport, F., Kaplan, D., Raulin, F., 2020. Testing the capabilities of the Mars Organic Molecule Analyser (MOMA) chromatographic columns for the separation of organic compounds on Mars. Planetary and Space Science 186, 104903. is our planetary neighbor and is now known to host trace levels of organic matter at its surface. However, little is known of the organic molecular composition or the survival potential for organic biosignatures, such as the enantiomeric excess of amino acids or the carbon chain patterns of lipid hydrocarbons, as a function of depth below the martian surface. The Mars Organic Molecule Analyser (MOMA) is an instrument onboard the Rosalind Franklin rover that is scheduled to be launched to Mars in 2022 as part of the ExoMars mission. This experiment includes a gas chromatograph instrument dedicated to the in situ analysis of organic molecules and their enantiomers present in martian samples collected by the rover at the surface down to 2 ?m depth. In order to evaluate the performance of the integrated chromatographic system which was selected for the flight model, experiments were carried out with a laboratory setup that reproduced the flight configuration and mimicked the in situ operating conditions. We show that the column instrument package can separate and detect a wide range of organic and inorganic volatile compounds, from noble gases to hydrocarbon chains with up to 29 carbon atoms (C29). We study the enantiomeric resolution of selected chiral chemical standards and compare our laboratory results to: i. tests performed with the same instrumental setup but using a natural sample spiked with amino acids in order to evaluate the influence of a mineral phase on the analysis, and ii. tests run on a MOMA engineering test unit (ETU) which is representative of the flight model. In each case, tests on the more complex sample and the more flight-like instrument allow a comparison with laboratory results, in order to confirm that laboratory data are reliable for supporting peak identification within flight data. The obtained results demonstrate the ability of the gas chromatographic subsystem to identify a wide range of organic and inorganic volatile compounds, including biomolecular signatures, within the constrained space operating conditions of MOMA. The results form a retention time and mass spectral database for MOMA which will be critical for analysis of the eventual flight data.Hackley, P.C., Cardott, B.J., 2020. Sample mounting for organic petrology: No thermal effects from transient exposure to elevated temperatures. International Journal of Coal Geology 223, 103446. sample mounting, organic petrology laboratories typically use cold-setting epoxy-resin (e.g., 40?°C, used by Oklahoma Geological Survey, OGS) or heat-setting thermoplastic (e.g., 180?°C, used by U.S. Geological Survey, USGS). Previous workers have suggested a systematic huminite/vitrinite reflectance (VRo) increase was associated with the thermoplastic preparation process, relative to epoxy mounting, which was possibly attributed to moisture loss from organic matter due to the transient high temperatures of plastic mounting. In this study, we evaluated thermal effects to low thermal maturity organic matter from transient exposure to elevated temperatures. A subbituminous coal sample was subjected to long-term (4 to 38?weeks) exposure to temperatures of 85 to 120?°C and afterward evaluated by multiple approaches to test thermal advance [elemental analyses, Rock-Eval pyrolysis, Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR), pyrolysis gas chromatography, and petrographic analyses, including huminite/vitrinite reflectance and spectral fluorescence], all of which showed no detectable systematic (statistically insignificant) changes between the original sample and its heat-treated products. We also compared huminite/vitrinite reflectance of six low thermal maturity samples (those most likely to react to transient heating) mounted via both cold-setting epoxy-resin and heat-setting thermoplastic. Results indicate measured VRo of a sample prepared by one mounting process was within the standard deviation of reflectance for the same sample prepared via the other process. Moreover, VRo results were not systematically higher in thermoplastic mounts. Contrary to previous work, these results suggest thermoplastic mounting or other transient exposure to elevated temperatures does not impact thermal maturity estimates from reflectance measurement for low thermal maturity organic samples. Furthermore, the average interlaboratory difference in measured VRo (between OGS and USGS) for the same sample prepared by either epoxy-resin or thermoplastic mounting was 0.038%, about double the average difference between VRo for the same sample prepared via epoxy-resin versus thermoplastic in a single laboratory (0.024%). This result indicates interlaboratory variability impacts VRo measurement reproducibility to the extent that systematic differences could not be observed between thermoplastic and cold-setting sample preparation approaches, even if such differences were present.Hackley, P.C., Jubb, A.M., Burruss, R.C., Beaven, A.E., 2020. Fluorescence spectroscopy of ancient sedimentary organic matter via confocal laser scanning microscopy (CLSM). International Journal of Coal Geology 223, 103445. spectroscopy via confocal laser scanning microscopy (CLSM) was used to analyze ancient sedimentary organic matter, including Tasmanites microfossils in Devonian shale and Gloecapsomorpha prisca (G. prisca) in Ordovician kukersite from North American basins. We examined fluorescence emission as a function of excitation laser wavelength, sample orientation, and with respect to location within individual organic entities and in transects across bedded organic matter. Results from spectral scans of the same field of view in Tasmanites with different laser lines showed progressive red-shift in emission maxima with longer excitation wavelengths. This result indicates steady-state Tasmanites fluorescence emission is an overlapping combination of emission from multiple fluorophore functions. Stokes shift decreased with increasing excitation wavelength, further suggesting the presence of multiple fluorophore functions with different S1?→?S0 transition energies. This observation also indicates that at longer excitation wavelengths, less absorbed light energy is dissipated via collisional transfer than at shorter excitation wavelengths and may suggest fewer polar functions are preferentially absorbing. Confirming earlier results, emission spectra observed from high fluorescence intensity regions (fold apices) in individual Tasmanites are blue-shifted relative to emission from other locations in the same microfossil. We suggest high intensity emission is from photoselective alignment of polarized excitation with the fluorophore absorption and emission transition moment. The blue shift observed in regions of high intensity emission may be due to relative absence or realignment of polar species, e.g., bridging ether or ester functions, although variations in O abundance could not be confirmed with preliminary time-of-flight secondary ion mass spectrometry (TOF-SIMS) analysis. Tasmanites occurring in consolidated sediments are flattened from original spherical morphology and, in optical microscopy, this burial deformation results in generally parallel extinction (strain-influenced) and positive elongation. The deformation also induces fluorescence anisotropy observed as variations in emission wavelength when individual Tasmanites are measured from their long axis parallel to bedding, whereas this effect is absent in bedding-normal view. Transects from G. prisca-rich source layers into adjacent reservoir layers show decrease in fluorescence intensity and spectral red-shift (increase in full-width half-maximum with increasing red portion of the half-width). These results may suggest an increase in fluorescence quenching across the source-to-reservoir transition zone, consistent with an increase in aromaticity following petroleum expulsion and migration. These observations are supported by increasing reflectance values measured across similar micro-scale transects. Our results highlight the applicability of CLSM as a broad and under-utilized approach for the characterization of sedimentary organic matter and are discussed with perspective toward petroleum processes and thermal indices research.Han, W., Chang, X., Ma, W., Tao, S., Yao, J., Hou, L., Yang, W., 2020. Geochemical characteristics and reasons for the carbon isotopic reversal of natural gas in the southern Jingbian gas field, Ordos Basin, China. Geological Magazine 157, 527-538. carbon isotope value of ethane in the southern part of the Jingbian gas field is lower than that in the northern part, indicating a carbon isotopic reversal in the southern Jingbian gas field (δ13Cmethane > δ13Cethane). Through comparing the geochemical characteristics of gases in the southern and northern parts of the gas field, the reasons for the carbon isotopic reversal in the southern Jingbian gas field were determined to be high thermal maturity and mixing action. When thermal maturity reaches a critical value, the carbon isotope value of ethane becomes relatively more depleted with thermal maturity. Although the carbon isotope value of methane increases with thermal maturity, the extent is relatively smaller. Finally, the rare phenomenon of δ13Cmethane > δ13Cethane occurs. High thermal maturity leads to the secondary thermal cracking of gases. Mixing of the cracked gases and primary gases also leads to carbon isotopic reversal. Both of the above mechanisms share a common premise, which is high thermal maturity.Han, X., Tomaszewski, E.J., Sorwat, J., Pan, Y., Kappler, A., Byrne, J.M., 2020. Effect of microbial biomass and humic acids on abiotic and biotic magnetite formation. Environmental Science & Technology 54, 4121-4130. (Fe3O4) is an environmentally ubiquitous mixed-valent iron (Fe) mineral, which can form via biotic or abiotic transformation of Fe(III) (oxyhydr)oxides such as ferrihydrite (Fh). It is currently unclear whether environmentally relevant biogenic Fh from Fe(II)-oxidizing bacteria, containing cell-derived organic matter, can transform to magnetite. We compared abiotic and biotic transformation: (1) abiogenic Fh (aFh); (2) abiogenic Fh coprecipitated with humic acids (aFh-HA); (3) biogenic Fh produced by phototrophic Fe(II)-oxidizer Rhodobacter ferrooxidans SW2 (bFh); and (4) biogenic Fh treated with bleach to remove biogenic organic matter (bFh-bleach). Abiotic or biotic transformation of Fh was promoted by Feaq2+ or Fe(III)-reducing bacteria. Feaq2+-catalyzed abiotic reaction with aFh and bFh-bleach led to complete transformation to magnetite. In contrast, aFh-HA only partially (68%) transformed to magnetite, and bFh (17%) transformed to goethite. We hypothesize that microbial biomass stabilized bFh against reaction with Feaq2+. All four Fh substrates were transformed into magnetite during biotic reduction, suggesting that Fh remains bioavailable even when associated with microbial biomass. Additionally, there were poorly ordered magnetic components detected in the biogenic end products for aFh and aFh-HA. Nevertheless, abiotic transformation was much faster than biotic transformation, implying that initial Feaq2+ concentration, passivation of Fh, and/or sequestration of Fe(II) by bacterial cells and associated biomass play major roles in the rate of magnetite formation from Fh. These results improve our understanding of factors influencing secondary mineralization of Fh in the environment.Han, Y., Yin, F., John, G.F., Clement, T.P., 2020. Understanding the relative performance of SCAN, SIM, PMRM and MRM methods for quantifying polycyclic aromatic hydrocarbons in crude oil samples. Rapid Communications in Mass Spectrometry 34, e8765.: Polycyclic aromatic hydrocarbons (PAHs) present in oil spill samples are analyzed by gas chromatography/mass spectrometry (GC/MS) and gas chromatography/tandem mass spectrometry (GC/MS/MS) using four different methods: (1) full scan (SCAN), (2) selected ion monitoring (SIM), (3) multiple reaction monitoring (MRM), and (4) pseudo multiple reaction monitoring (PMRM). This study quantifies the relative performance of these methods.Methods: Novel experiments were designed to measure the signal‐to‐noise (S/N) ratios of all four methods. This was accomplished by spiking the crude oil with five deuterated PAHs (dPAHs) in two distinct ways: (1) varying the background noise by changing crude oil concentrations before spiking the samples with 1?ng/mL of dPAHs, and (2) varying the signal by spiking dPAHs concentrations of 0.5 and 5?ng/mL into a crude oil sample.Results: The MRM method is the most selective and sensitive of the four methods. It also provides the lowest limit of detection (LOD) and limit of quantitation (LOQ). MRM is the optimal approach for quantifying PAHs in complex petroleum samples containing high levels of background noise. Also, our data show that the PAHs in complex oil spill samples can be quantified by MRM without using any complicated sample preparation steps.Conclusions: Based on our experimental data, the relative performance of the four methods used for quantifying PAHs in crude oil samples can be ranked as MRM?>?PMRM?>?SIM?>?SCAN.Handhal, A.M., Al-Abadi, A.M., Chafeet, H.E., Ismail, M.J., 2020. Prediction of total organic carbon at Rumaila oil field, southern Iraq using conventional well logs and machine learning algorithms. Marine and Petroleum Geology 116, 104347. organic carbon (TOC) is an important parameter for assessing the hydrocarbon potential of source rocks. The standard method for analysis of TOC is the Rock-Eval pyrolysis on cutting and core samples. The coring process is always expensive and time consuming. Therefore, researchers around the world focused on developing techniques to estimate TOC and other organic parameters from readily available well logs data that are almost available in all wells. In this study, we evaluated the use of three machine learning models namely, random forest (RF), rotation forest (rF), k nearest neighbors (KNN) to estimate TOC based on conventional well logs data. The well logs involved gamma ray, acoustic, density, neutron, and deep resistivity. The efficacy of the models was tested against the most widely used backpropagation artificial neutral network (BPANN) and support vector regression (SVR) models. North Rumaila oilfield in southern Iraq was taken as a case study. The models were trained and tested using data from two wells in the field, namely R-167 and R-172. The number of TOC measurements used for training and testing were 40 (R-167) and 18 (R-172), respectively. The efficacy of the used algorithms was evaluated using mean absolute error (MAE), root mean squared error (RMSE), and correlation of determination (R2). The models are also visually compared using Taylor diagram and violin plot to distinguish the best performance model. Results indicated the KNN was the best followed by RF and then rF. The worst performance models were BPANN and SVR models. This study confirmed the ability of machine learning models for building efficient model for estimating TOC from readily available borehole logs data without the need for very expensive coring process.Hardy, B.L., Moncel, M.H., Kerfant, C., Lebon, M., Bellot-Gurlet, L., Mélard, N., 2020. Direct evidence of Neanderthal fibre technology and its cognitive and behavioral implications. Scientific Reports 10, 4889. are often considered as less technologically advanced than modern humans. However, we typically only find faunal remains or stone tools at Paleolithic sites. Perishable materials, comprising the vast majority of material culture items, are typically missing. Individual twisted fibres on stone tools from the Abri du Maras led to the hypothesis of Neanderthal string production in the past, but conclusive evidence was lacking. Here we show direct evidence of fibre technology in the form of a 3-ply cord fragment made from inner bark fibres on a stone tool recovered in situ from the same site. Twisted fibres provide the basis for clothing, rope, bags, nets, mats, boats, etc. which, once discovered, would have become an indispensable part of daily life. Understanding and use of twisted fibres implies the use of complex multi-component technology as well as a mathematical understanding of pairs, sets, and numbers. Added to recent evidence of birch bark tar, art, and shell beads, the idea that Neanderthals were cognitively inferior to modern humans is becoming increasingly untenable.Harps, L.C., Schipperges, S., Bredendiek, F., Wuest, B., Borowiak, A., Parr, M.K., 2020. Two dimensional chromatography mass spectrometry: Quantitation of chiral shifts in metabolism of propranolol in bioanalysis. Journal of Chromatography A 1617, 460828. this study a heart-cutting 2D-LC method was successfully developed and optimized in order to discriminate and quantitate (S)-propranolol, (R)-propranolol, and its hydroxy metabolites, namely the isomeric (S)-4′?hydroxy propranolol, (R)-4′?hydroxy propranolol, (S)-5′?hydroxy propranolol, (R)-5′?hydroxy propranolol, (S)-7′-hydroxy propranolol, and (R)-7′?hydroxy propranolol in one chromatographic run. Thereby, experiments investigating chiral discrimination in ring hydroxylation of propranolol were made feasible.Analysis of human urine samples after administration of a single oral dose of 40 mg of propranolol clearly revealed considerable chiral shifts in propranolol and its 4′-, 5′-, and 7′-hydroxy metabolites. Furthermore, the excretion rates of the individual (S)- and (R)-enantiomers were continuously monitored over 24 h post administration.Studies were performed utilizing a 2D-LC system hyphenated to a triple quadrupole mass spectrometer. The chromatographic system was endued with a reversed phase column (phenyl-hexyl) in first dimension and a teicoplanin based chiral column in second dimension. The method was basically validated and successfully evaluated as robust. Calibration was performed achieving accuracy between 80% and 120%. Maximal excretion rates of (S)-propranolol, (R)-propranolol, (S)-4′?hydroxy propranolol, (R)-4′?hydroxy propranolol, (S)-5′?hydroxy propranolol, (R)-5′?hydroxy propranolol, and (R)-7′?hydroxy propranolol were 237 ng/min, 281 ng/min, 4 ng/min, 4 ng/min, 1 ng/min, 9 ng/min, and 3 ng/min, respectively.Hartman, G., Brittingham, A., Gilboa, A., Hren, M., Maas, K., Pilver, J., Weiss, E., 2020. Post-charring diagenetic alteration of archaeological lentils by bacterial degradation. Journal of Archaeological Science 117, 105119. seeds recovered from archaeological contexts are typically protected from degradation through the process of low temperature charring (<300?°C). Resilient Maillard Reaction Products produced by charring are considered chemically stable, and thus, suitable for stable isotopic studies. A few high-profile reconstructions of past climate and human economies have been based on charred seeds. In this study we take a comprehensive structural, compositional, isotopic, and genetic approach to compare modern Eastern Mediterranean lentils with archaeological charred lentils recovered from Iron Age I layer Tel Dor, and five complementary southern Levantine sites ranging from the Pre-Pottery Neolithic to Persian periods. The modern lentils were charred at temperatures ranging from 100?C - 400?C and analyzed as a reference for the archaeological material. The modern and archaeological charred lentils were found to differ structurally, compositionally, and isotopically, challenging the notion that seed charring prevents further chemical alteration between the time of burial and recovery of the seeds. Genetic analysis of archaeological lentils revealed the presence of bacterial taxa capable of degrading chemical compounds considered stable in ambient burial conditions. We assume that microbial degradation is more likely to affect charred legumes than other seeds due to their high nitrogen content. We also acknowledge that different environments and burial conditions might promote better preservation of charred lentils. We call for the development and employment of archaeological legume screening methods that will help select seeds best suited for isotopic analyses.Hayes, R.F., Puggioni, G., Parker, W.G., Tiley, C.S., Bednarick, A.L., Fastovsky, D.E., 2020. Modeling the dynamics of a Late Triassic vertebrate extinction: The Adamanian/Revueltian faunal turnover, Petrified Forest National Park, Arizona, USA. Geology 48, 318-322. coincidence of a diverse vertebrate assemblage with a high-precision geochronology and lithostratigraphy in Petrified Forest National Park (Arizona, USA) allows Bayesian quantification of the dynamics of a Late Triassic vertebrate extinction and replacement, the Adamanian/Revueltian (A/R) faunal turnover. This approach uniquely identifies probabilities for the tempo of the replacement of the Adamanian assemblage by that of the Revueltian, precisely tracking the turnover. While the method does not designate the moment of extinction, there is a negligible probability that all Adamanian extinctions, as well as all Revueltian originations, are synchronous. A protracted A/R turnover is incompatible with the geologically instantaneous Manicouagan impact (215.4 ± 0.20 Ma; Québec, Canada) as a dominant causal mechanism. This analytical framework constitutes a flexible means of reconstructing biotic turnover in a variety of deep time contexts.He, K., Pan, Y., 2020. Magnetofossil abundance and diversity as paleoenvironmental proxies: A case study from southwest Iberian margin sediments. Geophysical Research Letters 47, e2020GL087165.: It is still contentious how the abundance and diversity of magnetofossils reflect varying paleoenvironmental conditions. Here, we apply rock magnetic methods and transmission electron microscopy to identify magnetofossils in the core MD01‐2444 from the southwestern Iberian margin during the period 49.6–18.5 ka and 193.8–171.7 ka. Results show a correlation between the biogenic magnetite component and contrasting paleoenvironmental conditions. Specifically, remanence ratio (Mrs/Ms), the ratio of anhysteretic susceptibility (χARM) to saturation isothermal remanant magnetization (SIRM), fractions of biogenic soft and biogenic hard components (BS + BH), and delta–delta ratio (δFC/δZFC) have a negative relationship with planktonic δ18O, suggesting that more magnetofossils existed in sediments during warmer periods. Combining transmission electron microscopy images with paleoenvironmental proxies, we found that the proportions of bullet‐shaped magnetofossils increased in a warmer and less oxic environment, while isotropic shapes dominated in cooler and oxic environments.Plain Language Summary: Magnetotactic bacteria are a group of microorganisms that produce intracellular nanometer‐sized magnetite and/or greigite minerals. Those magnetic particles preserved in muds, called magnetofossils, can be served as clues of past climate change. Using rock magnetic method along with electron microscopy analysis, we found that more magnetite magnetofossils existed in muds of warmer period from a marine core of the southwestern Iberian margin during the periods 49.6–18.5 ka and 193.8–171.7 ka. Combining with previously published results of physical and chemical analysis of the same core, we found the proportions of bullet‐shaped bacterial crystals increased in the warmer and relatively anoxic periods, whereas equant ones dominated in the cooler and relatively oxic environment. Our results suggest that the abundance and crystal shape of magnetofossils are sensitive to past climate change.Heard, A.W., Dauphas, N., 2020. Constraints on the coevolution of oxic and sulfidic ocean iron sinks from Archean–Paleoproterozoic iron isotope records. Geology 48, 358-362. drivers of Fe isotope variations of Archean–Paleoproterozoic pyrite have been debated since discovery of δ56Fe values (per mil shifts in 56Fe/54Fe ratios versus iron isotopic reference material [IRMM-014]) as low as ?3.5‰ in pyrites predating the Great Oxygenation Event (GOE) at ca. 2330 Ma. These values were taken as evidence that extensive removal of high-δ56Fe Fe3+ oxides during partial oxidation of upwelled Fe2+-rich waters occurred in the early oceans. However, low pyrite δ56Fe can also reflect kinetic isotopic shifts during pyrite formation. Compiled δ56Fe records of oxic (iron formation) and sulfidic (pyrite) sinks of Fe negatively covary before the GOE, contrary to expectations that Fe2+ oxidation would drive the δ56Fe values of these sinks on parallel trends as oxidation progressed. Positive covariation of pyrite δ56Fe with the dispersion of sedimentary sulfide δ34S fractionation through time suggests that sulfur availability during pyritization at least partially drove trends in negative δ56Fe fractionation before the GOE. The δ56Fe records of pyrite and iron formation suggest that oxic and sulfidic Fe sinks grew in concert before and during the GOE.Heddam, S., Keshtegar, B., Kisi, O., 2020. Predicting total dissolved gas concentration on a daily scale using kriging interpolation, response surface method and artificial neural network: Case study of Columbia River Basin dams, USA. Natural Resources Research 29, 1801-1818. dissolved gas (TDG) is an important factor for aquatic life and can cause gas bubble trauma in fish if the concentration is higher than 110%. Dissolved gas is entrained in the water over the spillways of dams. Generally, total dissolved gas is simulated and predicted using models based on fluid mechanics, hydrodynamics and mass exchange processes. In the present study, two novel data-driven techniques, namely kriging interpolation method (KIM) and response surface method (RSM), were proposed for predicting total dissolved gas, measured on a daily scale at the upstream and downstream of spillways at four different dams’ reservoir sites located in Columbia River, USA. For developing models, we selected several input variables, namely water temperature, barometric pressure, spill from dam and discharge; in addition, total dissolved gas measured as percent of saturation (%) was selected as the predicted variable. Results obtained from the newly proposed models were compared with those obtained with the standard feedforward neural networks (FFNN) model to assess their performances. The proposed models were developed and compared with each other based on several input combinations. Four statistical indexes were utilized to evaluate models’ performances: coefficient of correlation (R), Nash–Sutcliffe efficiency (NSE), root-mean-squared error (RMSE) and mean absolute error (MAE). The results obtained clearly show that: (1) the KIM model is better than the RSM and FFNN models at three dams and FFNN is the best for the fourth; (2) the RSM model is ranked in the third place and provided the lowest accuracy; and (3) the highest R and NSE in addition to the lowest RMSE and MAE are obtained when the models include all the four input variables. The R, NSE, RMSE and MAE of the best KIM model among the four dam’s reservoirs are 0.973, 0.941, 1.462 and 1.122 while the corresponding values of the best FFNN (RSM) model are 0.962 (0.952), 0.926 (0.906), 1.643 (1.848) and 1.297 (1.426), respectively.Heiles, S., Kompauer, M., Müller, M.A., Spengler, B., 2020. Atmospheric-pressure MALDI mass spectrometry imaging at 213 nm laser wavelength. Journal of the American Society for Mass Spectrometry 31, 326-335. results for a new atmospheric-pressure matrix-assisted laser desorption/ionization (MALDI) mass spectrometry imaging source operating at 213 nm laser wavelength are presented. The activation of analytes in the 213 nm MALDI process at atmospheric pressure was evaluated and compared to results for 337 nm MALDI and electrospray ionization using thermometer molecules. Different sample preparation techniques for nicotinic acid, the matrix with the highest ionization efficiency at 213 nm of all tested matrices, were evaluated and optimized to obtain small crystal sizes, homogenous matrix layer sample coverage, and high ion signal gains. Mass spectrometry imaging experiments of phospholipids in mouse tissue sections in positive- and negative-ion mode with different lateral resolutions and the corresponding pre-/post-mass spectrometry imaging workflows are presented. The use of custom-made objective lenses resulted in sample ablation spot diameters of on average 2.9 μm, allowing mass spectrometry imaging experiments to be performed with 3 μm pixel size without oversampling. The ion source was coupled to an orbital trapping mass spectrometer offering high mass resolution (>100.000), high mass accuracy (≤ ±2 ppm), and high sensitivity (single pixel on-tissue tandem MS from 6.6 μm2 ablation area). The newly developed 213 nm atmospheric-pressure MALDI source combines the high mass resolution and high mass accuracy performance characteristics of orbital trapping mass spectrometers with high lateral resolution (pixel size ～3 μm) mass spectrometry imaging.Hemingway, J.D., Olson, H., Turchyn, A.V., Tipper, E.T., Bickle, M.J., Johnston, D.T., 2020. Triple oxygen isotope insight into terrestrial pyrite oxidation. Proceedings of the National Academy of Sciences 117, 7650-7657.: Pyrite is oxidized during weathering to form dissolved sulfate that is carried to the ocean by rivers. This process is thought to incorporate atmospheric O2-derived oxygen; geologically preserved sulfate has thus been proposed to directly trace past O2 isotope compositions. However, this mechanism has not been thoroughly tested in modern weathering environments. We show that dissolved sulfate in Himalayan rivers is predominantly derived from pyrite, yet its oxygen isotope compositions preclude direct O2 incorporation. Rather, alternative oxygen sources (e.g., reactive oxygen species) may be incorporated during oxidation, prompting reconsideration of the pyrite oxidation mechanism and the interpretation of geologically preserved sulfate as a direct O2 tracer.Abstract: The mass-independent minor oxygen isotope compositions (Δ′17O) of atmospheric O2 and pO2/pCO2 are primarily regulated by their relative partial pressures, pO2/pCO2. Pyrite oxidation during chemical weathering on land consumes O2 and generates sulfate that is carried to the ocean by rivers. The Δ′17O values of marine sulfate deposits have thus been proposed to quantitatively track ancient atmospheric conditions. This proxy assumes direct O2 incorporation into terrestrial pyrite oxidation-derived sulfate, but a mechanistic understanding of pyrite oxidation—including oxygen sources—in weathering environments remains elusive. To address this issue, we present sulfate source estimates and Δ′17O measurements from modern rivers transecting the Annapurna Himalaya, Nepal. Sulfate in high-elevation headwaters is quantitatively sourced by pyrite oxidation, but resulting Δ′17O values imply no direct tropospheric O2 incorporation. Rather, our results necessitate incorporation of oxygen atoms from alternative, 17O-enriched sources such as reactive oxygen species. Sulfate Δ′17O decreases significantly when moving into warm, low-elevation tributaries draining the same bedrock lithology. We interpret this to reflect overprinting of the pyrite oxidation-derived Δ′17O anomaly by microbial sulfate reduction and reoxidation, consistent with previously described major sulfur and oxygen isotope relationships. The geologic application of sulfate Δ′17O as a proxy for past pO2/pCO2 should consider both 1) alternative oxygen sources during pyrite oxidation and 2) secondary overprinting by microbial recycling.Herries, A.I.R., Martin, J.M., Leece, A.B., Adams, J.W., Boschian, G., Joannes-Boyau, R., Edwards, T.R., Mallett, T., Massey, J., Murszewski, A., Neubauer, S., Pickering, R., Strait, D.S., Armstrong, B.J., Baker, S., Caruana, M.V., Denham, T., Hellstrom, J., Moggi-Cecchi, J., Mokobane, S., Penzo-Kajewski, P., Rovinsky, D.S., Schwartz, G.T., Stammers, R.C., Wilson, C., Woodhead, J., Menter, C., 2020. Contemporaneity of Australopithecus, Paranthropus, and early Homo erectus in South Africa. Science 368, eaaw7293.: Understanding the extinction of Australopithecus and origins of Paranthropus and Homo in South Africa has been hampered by the perceived complex geological context of hominin fossils, poor chronological resolution, and a lack of well-preserved early Homo specimens. We describe, date, and contextualize the discovery of two hominin crania from Drimolen Main Quarry in South Africa. At ~2.04 million to 1.95 million years old, DNH 152 represents the earliest definitive occurrence of Paranthropus robustus, and DNH 134 represents the earliest occurrence of a cranium with clear affinities to Homo erectus. These crania also show that Homo, Paranthropus, and Australopithecus were contemporaneous at ~2 million years ago. This high taxonomic diversity is also reflected in non-hominin species and provides evidence of endemic evolution and dispersal during a period of climatic variability.Editor' summary: Dating the Drimolen hominins. Fossil hominins from South Africa are enriching the story of early human evolution and dispersal. Herries et al. describe the geological context and dating of the hominin-bearing infilled cave, or palaeocave, at a site called Drimolen in South Africa (see the Perspective by Antón). They focus on the age and context of a recently discovered Homo erectus sensu lato fossil and a Paranthropus robustus fossil, which they dated to ～2.04 million to 1.95 million years ago. This makes Drimolen one of the best-dated sites in South Africa and establishes these fossils as the oldest definitive specimens of their respective species ever discovered. The age confirms that species of Australopithecus, Paranthropus, and early Homo overlapped in the karst of South Africa ～2 million years ago.Structured AbstractIntroduction: Drimolen is one of several ancient caves located in the Hominid Caves of South Africa United Nations Educational, Scientific, and Cultural Organization (UNESCO) World Heritage Area in South Africa. Between ~2.3 million and ~1.8 million years ago, there were major climactic changes and faunal turnovers in the region, including the last occurrence of the genus Australopithecus and the first occurrence of Paranthropus and Homo, as well as the first occurrence of stone and bone tools. However, the exact nature of these changes has been hard to elucidate because of past difficulties in dating caves of this age and their perceived geological complexity. Unlike in eastern Africa, where volcanic material is available for dating, the South African caves have been dated with a variety of evolving methods that have often given conflicting age estimates. This means that South Africa’s early human record and its relationship to east African hominin species have been difficult to determine. This is especially problematic given that each record is distinct in terms of hominin species until perhaps the origin and early evolution of the genus Homo. Although many fragmentary fossil specimens in South Africa have been attributed to early Homo, there is no consensus regarding species attribution.Rationale: Drimolen Main Quarry has yielded one of the richest records of early human fossils in South Africa, including examples of Homo and the most complete female skull (DNH 7) of Paranthropus robustus. Excavations between 2015 and 2018 yielded the first new hominin calvaria (DNH 134 and DNH 152) from the site in 20 years. A combination of uranium-lead dating on flowstones, uranium-series electron spin resonance (US-ESR) dating on teeth, and palaeomagnetism on sediments was undertaken to establish the age of the site and its early human fossils.Results: The DNH 134 cranium shares clear affinities with Homo erectus, whereas the DNH 152 cranium represents P. robustus. Stratigraphic analysis of the Drimolen Main Quarry deposits indicates that unlike many other South African sites, there was only one major phase of relatively short deposition between ~2.04 million years ago and ~1.95 million years ago. This age has been constrained by the identification of the ~1.95-million-year-old magnetic field reversal at the base of the Olduvai SubChron within the sediments and by the direct uranium-lead dating of a flowstone that formed during the reversal. This has been augmented by direct dating on fossils by means of US-ESR that suggests that the DNH 134 and DNH 152 crania were deposited just before this reversal, with the DNH 134 crania deposited at ~2.04 million years ago. The DNH 134 cranium shares affinities with H. erectus and predates all known specimens in that species. The age range of Drimolen Main Quarry overlaps with that of Australopithecus sediba from the nearby site of Malapa and indicates that Homo, Paranthropus, and Australopithecus were contemporaneous in South Africa between 2.04 million and 1.95 million years ago. It is the first time that dating has conclusively demonstrated that these three taxa shared the same landscape during the same time range, making it less likely that a population of A. sediba is ancestral to Homo, as has been previously suggested. Analysis of fauna preserved at Drimolen documents a period of ecological change, with earlier South African species going extinct and new species moving into the region from other parts of Africa, including early representatives of H. erectus.Conclusion: Drimolen is the best dated early hominin site in South Africa. DNH 134 is the oldest and best preserved Early Pleistocene Homo cranium from South Africa. The DNH 134 Homo cranium has affinities with H. erectus and extends the species’ temporal range by ~200,000 to 150,000 years. DNH 134 being older than A. sediba complicates the likelihood of this species being ancestral to Homo in South Africa, as previously suggested. With the oldest occurrence of H. erectus at the southern tip of Africa, this argues against a suggested Asian origin for H. erectus. DNH 152 represents the oldest P. robustus cranium in South Africa. The Drimolen stone and bone tools are also the oldest from the region.The faunal community from Drimolen as a whole indicates substantial changes in South African ecosystems, with many first and last appearance dates of species that are related to the extinction of some indigenous South African species and the migration of others into the region ~2 million years ago, likely including Homo erectus.Herzog, S.D., Gentile, L., Olsson, U., Persson, P., Kritzberg, E.S., 2020. Characterization of iron and organic carbon colloids in boreal rivers and their fate at high salinity. Journal of Geophysical Research: Biogeosciences 125, e2019JG005517. colloids are important carriers of macronutrients, trace metals, and pollutants into marine waters. The aim of the current study was to extend the understanding of iron (Fe) and organic carbon (OC) colloids in boreal rivers and their fate at higher salinities. X‐ray absorbance spectroscopy (XAS) and dynamic light scattering (DLS) were combined to explore Fe speciation and colloidal characteristics such as size and surface charge and how these are affected at increasing salinity. XAS confirmed the presence of two Fe phases in the river waters—Fe‐organic matter (OM) complexes and Fe(oxy)hydroxides. From DLS measurements on filtered and unfiltered samples, three particle size distributions were identified. The smallest particles (10–40 nm) were positively charged and suggested to consist of essentially bare Fe(oxy)hydroxide nanoparticles. The largest particles (300–900 nm) were dominated by Fe(oxy)hydroxides associated with chromophoric molecular matter. An intermediate size distribution (100–200 nm) with a negative surface charge was presumably dominated by OM and containing Fe‐OM complexes. Increasing the salinity resulted in a removal of the smallest distribution. Unexpectedly, both the intermediate and largest size distributions were still detected at high salinity. The collective results suggest that Fe(oxy)hydroxides and Fe‐OM complexes are both found across the wide size range studied and that colloidal size does not necessarily reflect either Fe speciation or stability toward salinity‐induced aggregation. The findings further demonstrate that also particles beyond the typically studied <0.45‐μm size range should be considered to fully understand the riverine transport and fate of macronutrients, trace metals, and pollutants.Heuillet, M., Millard, P., Cissé, M.Y., Linares, L.K., Létisse, F., Manié, S., Le Cam, L., Portais, J.-C., Bellvert, F., 2020. Simultaneous measurement of metabolite concentration and isotope incorporation by mass spectrometry. Analytical Chemistry 92, 5890-5896. of the topology, functioning, and regulation of metabolic systems are based on two main types of information that can be measured by mass spectrometry: the (absolute or relative) concentration of metabolites and their isotope incorporation in 13C-labeling experiments. These data are currently obtained from two independent experiments because the 13C-labeled internal standard (IS) used to determine the concentration of a given metabolite overlaps the 13C-mass fractions from which its 13C-isotopologue distribution (CID) is quantified. Here, we developed a generic method with a dedicated processing workflow to obtain these two sets of information simultaneously in a unique sample collected from a single cultivation, thereby reducing by a factor of 2 both the number of cultivations to perform and the number of samples to collect, prepare, and analyze. The proposed approach is based on an IS labeled with other isotope(s) that can be resolved from the 13C-mass fractions of interest. As proof-of-principle, we analyzed amino acids using a doubly labeled 15N13C-cell extract as IS. Extensive evaluation of the proposed approach shows a similar accuracy and precision compared to state-of-the-art approaches. We demonstrate the value of this approach by investigating the dynamic response of amino acids metabolism in mammalian cells upon activation of the protein kinase R (PKR)-like endoplasmic reticulum kinase (PERK), a key component of the unfolded protein response. Integration of metabolite concentrations and isotopic profiles reveals a reduced de novo biosynthesis of amino acids upon PERK activation. The proposed approach is generic and can be applied to other (micro)organisms, analytical platforms, isotopic tracers, or classes of metabolites.Heydari, A., Peyvandi, K., 2020. Study of biosurfactant effects on methane recovery from gas hydrate by CO2 replacement and depressurization. Fuel 272, 117681. application of gas hydrate as a significant source of energy, which substantially contains methane, has recently attracted the consideration of many researchers. One of the essential methods of methane recovery from hydrate deposits is to inject carbon dioxide and its replacement in the hydrate structure of methane. Due to the low efficiency of this method, it is required to improve and provide other solutions to enhance the rate of replacement. In this study, depressurized and injection of rhamnolipid by carbon dioxide were investigated in porous media. Accordingly, a set of experiments was conducted to capture the effect of rhamnolipid on the kinetics of the hydrate formation growth. Further, rhamnolipid was compared to the well-known chemical surfactant, sodium dodecyl sulfate (SDS). The results of this comparison revealed that rhamnolipid was able to reduce the induction time and the total time of the process by 99% and 84% compared to SDS, respectively. In addition, it increased the amount of gas consumed by 20%, with the hydrate kinetic growth rate enhanced by seven times higher than the SDS. Generally, as this surfactant is bio-comparable and offers excellent results on the kinetics of hydrate formation, it can be promising as an eco-friendly promoter and play a valuable role in the future of methane recovery industry. The results revealed that the injection of rhamnolipid could enhance the rate of replacement process by 72.6% and the amount of carbon dioxide storage by 10% compared to the initial experiment performed without biosurfactant.Hinrichs, J., Shastry, V., Junk, M., Hemberger, Y., Pitsch, H., 2020. An experimental and computational study on multicomponent evaporation of diesel fuel droplets. Fuel 275, 117727. this study, the preferential evaporation behavior of diesel fuel is investigated using a discrete continuous multicomponent (DCMC) evaporation model. By analyzing real diesel fuel composition data from a 2D gas chromatography (GCxGC) measurement, 180 individual species from 11 different hydrocarbon families could be identified. To utilize these detailed composition data in the DCMC model, four continuous distribution functions for normal paraffins, mono-naphthenics, mono-aromatics, and naphthenic-mono-aromatics have been derived, which cover 80% of the total diesel composition. A specific property database for these hydrocarbon groups was established and suitable correlations were derived. The DCMC model was validated with experimental results of evaporating acoustically levitated single diesel droplets. Gas temperatures up to 200?°C were investigated, where the diesel fuel did not evaporate completely due to the presence of very long-chain compounds with low volatilities. The DCMC model using the experimentally-based diesel composition successfully captures this trend. To prove the importance of using the DCMC model with experimentally based fuel composition data at diesel engine conditions, a single droplet was exposed to a gas environment of 700?°C. Here, the diesel droplet showed the longest lifetime, while dodecane, which is commonly used in diesel surrogate mixtures, evaporated significantly faster.Hirave, P., Wiesenberg, G.L.B., Birkholz, A., Alewell, C., 2020. Understanding the effects of early degradation on isotopic tracers: implications for sediment source attribution using compound-specific isotope analysis (CSIA). Biogeosciences 17, 2169-2180. of compound-specific isotope analysis (CSIA) in sediment fingerprinting source apportionment studies is becoming more frequent, as it can potentially provide robust land-use-based source attribution of suspended sediments in freshwater and marine systems. Isotopic tracers such as δ13C values of vegetation-derived organic compounds are considered to be suitable for the CSIA-based fingerprinting method. However, a rigorous evaluation of tracer conservativeness in terms of the stability of isotopic signature during detachment and transport of soil during erosion is essential for the suitability of the method. With the aim to identify potential fractionation and shifts in tracer signature during early degradation of organic matter in surface soils, we measured concentrations and δ13C values of long-chain fatty acids and n-alkanes from fresh plant biomass (as vegetation is a direct source of these compounds to the soils), degraded organic horizon (O horizon), and mineral soil (A horizon) from various forest types with different humus forms (five sites). The bulk δ13C values showed continuous 13C enrichment through the degradation stages from fresh plant material to the O and A horizons, ranging between 3.5?‰ and 5.6?‰. Compound-specific δ13C values showed a general 13C enrichment for both long-chain fatty acids (up to 5?‰) and n-alkanes (up to 3.9?‰) from fresh plant biomass to the O horizon overlying the A horizon. However, only slight or no further changes occurred from the O to the A horizon. We also compared compound-specific δ13C values between two soil particle size classes (<2?mm and <63??m) from four sites and found no significant differences of tracer values between them, with even less fractionation for the long-chain n-alkanes within the soil particle fractions. This points to the conclusion that sampling and analysing bulk soil material might be valid for the isotopic tracer applications. We further conclude that our results support the suitability of studied isotopic tracers as a representative source soil signature in the CSIA-based sediment source attribution, as they demonstrated necessary stability in the plant–soil system during organic matter degradation.Hoffmann, A.A., Borrok, D.M., 2020. The geochemistry of produced waters from the Tuscaloosa Marine Shale, USA. Applied Geochemistry 116, 104568. water is a byproduct of oil and gas production. The chemistry of produced water may provide information about the source of the fluid and its evolution, leading to an improved understanding of the hydrology of petroleum systems. In this study, samples from 19 wells from the Tuscaloosa Marine Shale (TMS) in Mississippi and Louisiana, USA were analyzed for their major and trace element compositions. Data obtained from produced waters from the TMS were compared to existing chemical data from produced waters collected from nearby hydrocarbon reservoir rocks within the Gulf Coast Basin. The results show that produced waters from the TMS are highly saline, with a mean concentration of 15.9?g/L of total dissolved solids. Comparison of the chemistry of produced water from the TMS to early flowback waters demonstrated a rapid shift from the more dilute fracturing fluid to the formation water endmember composition. Most of the trace metals showed a moderate to strong correlation with the overall salinity of the waters. Concentrations of Cu and V showed a moderate correlation with the amount of oil produced from the TMS wells, suggesting that these elements are strongly affiliated with the kerogen and subsequent dissolved (<0.45 μm) organic phases. Analysis of the volume of produced water compared to the volume of water used during hydraulic fracturing indicates that 15%–110% of the water volume used for fracking had been returned to the surface over the 2–5 year production period of the sampled wells. Chloride to bromide ratios suggest that the formation water in the TMS was derived from evaporated seawater. Comparison to historical data for produced waters in other formations in and around the Mississippi Salt Basin showed that waters in all the formations had a consistent origin (bitterns likely derived from the formation of the Louann salt). This implies that over geologic time periods fluids migrated through the TMS despite its low permeability present-day. The TMS also exhibited lower concentrations of dissolved transition metals such as Zn and Pb relative to those described in adjacent formations. This observation may suggest the presence of larger amounts of H2S, limiting the solubility of sulfide phases, in the shale unit relative to adjacent reservoir units.Hong, S.K., Yi, S., Shinn, Y.J., 2020. Middle Albian climate fluctuation recorded in the carbon isotope composition of terrestrial plant matter. Journal of Asian Earth Sciences 196, 104363. study presents the carbon isotopic record for terrestrial plant matter (δ13CTPM) in the Jinju Formation, Gyeongsang Basin, Korea, during the middle Albian. The measured δ13CTPM provides continuous high-resolution temporal variations for reconstructing climate change during the middle Albian, which has previously been poorly understood. We found that the δ13CTPM variation mostly exceeds the isotopic variation of the contemporaneous atmospheric CO2, indicating that the variation was primarily governed by climate change rather than atmospheric source. The δ13CTPM values corrected to modern atmospheric CO2 show cyclic fluctuations (?27.8‰ to ?23.3‰), reflecting a temporal variation of water availability and/or a related taxonomic turnover of plant communities in the hinterland of Jinju Lake. Based on a transfer function for estimating mean annual rainfall (MAR) from the measured δ13CTPM values, the middle Albian climate of the basin was found to vary from sub-humid to humid conditions (MAR: 500–1500 mm). This variability suggests that Albian climate change at middle latitudes occurred more frequently than previously interpreted. The temporal increase in aridity observed in the basin (35–38°N) has not been detected in the isotopic records of the Cretaceous Hokkaido section (42–45°N) in Japan. This difference implies the possibility of a periodic northward shift or expansion of the northern hemisphere subtropical high pressure belt.Huang, H., Babadagli, T., Chen, X., Andy Li, H., 2020. Performance comparison of novel chemical agents in improving oil recovery from tight sands through spontaneous imbibition. Petroleum Science 17, 409-418. sands are abundant in nanopores leading to a high capillary pressure and normally a low fluid injectivity. As such, spontaneous imbibition might be an effective mechanism for improving oil recovery from tight sands after fracturing. The chemical agents added to the injected water can alter the interfacial properties, which could help further enhance the oil recovery by spontaneous imbibition. This study explores the possibility of using novel chemicals to enhance oil recovery from tight sands via spontaneous imbibition. We experimentally examine the effects of more than ten different chemical agents on spontaneous imbibition, including a cationic surfactant (C12TAB), two anionic surfactants (O242 and O342), an ionic liquid (BMMIM BF4), a high pH solution (NaBO2), and a series of house-made deep eutectic solvents (DES3–7, 9, 11, and 14). The interfacial tensions (IFT) between oil phase and some chemical solutions are also determined. Experimental results indicate that both the ionic liquid and cationic surfactant used in this study are detrimental to spontaneous imbibition and decrease the oil recovery from tight sands, even though cationic surfactant significantly decreases the oil–water IFT while ionic liquid does not. The high pH NaBO2 solution does not demonstrate significant effect on oil recovery improvement and IFT reduction. The anionic surfactants (O242 and O342) are effective in enhancing oil recovery from tight sands through oil–water IFT reduction and emulsification effects. The DESs drive the rock surface to be more water-wet, and a specific formulation (DES9) leads to much improvement on oil recovery under counter-current imbibition condition. This preliminary study would provide some knowledge about how to optimize the selection of chemicals for improving oil recovery from tight reservoirs.Huang, H., Li, R., Xiong, F., Hu, H., Sun, W., Jiang, Z., Chen, L., Wu, L., 2020. A method to probe the pore-throat structure of tight reservoirs based on low-field NMR: Insights from a cylindrical pore model. Marine and Petroleum Geology 117, 104344. research proposes a new method of estimating pore-throat size distribution that converted based on nuclear magnetic resonance (NMR) T2 spectra, so as to more accurately explore the pore-throat structures of tight reservoirs. In this work, one of the most potential shale formations, Yanchang shales in the Ordos basin, NW China, was targeted. Take Chang 2 Member as an example, the experimental parameters were comprehensively analyzed, including petrological property analysis, NMR, and constant-rate mercury injection porosimetry (MIP).This research compared the pore-throat size distributions which are converted from NMR T2 spectra using a conventional method, an empirical formula method, and the new method. The research found that the results obtained through the linear relationship of the conventional method showed low accuracy, and the fitting coefficients vary from 0.5339 to 0.8238. Although the empirical method lacks physical significance and mathematical derivation, the fitting coefficients are from 0.8565 to 0.9886, which is referable. The new method brought in the physical significance of formula derivation and took into account the distribution characteristics of experimental data, resulting in higher fitting coefficients of 0.9928–0.9999. Based on the fitting results, the new method is more reasonable and feasible, which can be used for conversion of pore-throat size distribution through NMR T2 spectrum to obtain the NMR pore-throat structure.Huang, J., Babadagli, T., 2020. Efficiency improvement of heavy-oil recovery by steam-assisted gravity drainage injection using new generation chemicals. Energy & Fuels 34, 4433-4447. (steam-assisted gravity drainage) has been proven as an effective technology to enhance heavy oil/bitumen recovery. The main shortcoming of this method is its inefficiency, a result of high water and energy consumption. As a solution to SAGD efficiency improvement, we propose the addition of chemicals resulting in higher recovery and reduced steam consumption. The objective of this paper is to screen new generation chemicals as additives and study the mechanisms and optimum injection strategies. This screening was achieved through Hele-Shaw-type macroscopic visual experiments. We previously screened a wide variety of chemical additives for steam flooding. As a continuation of this work, these chemicals were tested for SAGD conditions using a new visual experimental design where the optimal injection strategies were identified, eventually providing a reference for the selection of chemical additives for field applications. Eleven conventional and new generation chemical additives (heptane, biodiesel, dimethyl ether, LTS-18, Tween 80, Span 80, Novelfroth 190, ionic liquid [BMMMIM BF4], silicon dioxide nanoparticle, DES 9, and DES 11) were selected based on both their strong thermal stability and enhanced oil recovery capability. The recovery improvement mechanisms for the different chemical additives and different injection strategies were identified through flow characteristics, emulsifying ability, viscosity reduction capability, and wettability alteration. Simultaneously, the mechanisms were studied from a macro perspective via analyzing areal sweep efficiency and microscopic oil displacement efficiency together with observing the images acquired during the process. Three different injection strategies were applied for each chemical: (1) chemicals were injected at the beginning, (2) in the middle, and (3) at the end of the steam injection. The chemical additives played different roles in recovery improvement, and different chemical addition strategies yielded different mechanisms. Heptane exhibited extraordinary characteristics with maximum “steam saving” (34.52%) when the middle injection strategy was applied, and maximum ultimate oil recovery (64.75%) was obtained for the end injection strategy due to the ability to reduce the viscosity of heavy oil by dissolving around the chamber edge. Steamflooding with Novelfroth 190 showed an excellent performance for the middle and end injection strategies because of its ability to develop rapid oil drainage “channels”. The addition of surfactant LST-18 presented the ability to improve the EOR by forming emulsions. Additionally, the distributions of the steam chamber in the Hele-Shaw cell were different because of the changed flow characteristics when the same chemical additive was injected at different times, thus showing the ability to reduce viscosity and form emulsions with different strengths.Ibad, S.M., Padmanabhan, E., 2020. Methane sorption capacities and geochemical characterization of Paleozoic shale Formations from Western Peninsula Malaysia: Implication of shale gas potential. International Journal of Coal Geology 224, 103480. sequences of overmatured Paleozoic black shales Formation were deposited in the Western Peninsula (WP) Malaysia, which can be considered as the potential shale gas reservoir. Therefore, to study the shale gas potential of the Paleozoic (Silurian-Permian) shale Formations, 146 samples from seven Formations were collected from WP Malaysia. A combination of methane sorption capacities, geochemical and trace element studies have been performed on the shale samples. The results indicate that the high pressure (up to 15 MPa) methane sorption capacity of the Silurian-Devonian, Devonian, Carboniferous, and Permian shales are between 0.079 and 0.154, 0.056 and 0.113, 0.052 and 0.094 and 0.085 and 0.169 mmol/g rock, respectively, at 30°C. Methane sorption capacities of the WP Malaysia shale were found to be greatly similar to sorption values of hot shales from Posidonia (Germany), Barnett (USA) and Longmaxi (China) shales. The measured total organic carbon (TOC) generally exceeded 2 wt% (average of 4 wt%), except for Carboniferous shales (>1 wt%). The biomarker analysis and Tmax values revealed that the kerogen has evolved into the metagenesis stage. The organic matter is likely comprises hydrogen-rich kerogen deposited under marine conditions in dysoxic to anoxic environment. After a comprehensive analysis, the Silurian-Devonian, Devonian and Permian shales in Western Peninsula Malaysia can be classified as potential gas shales based on their high TOC contents, presence of type III kerogen, high thermal maturity and significant methane sorption capacities.Iddphonce, R., Wang, J., Zhao, L., 2020. Review of CO2 injection techniques for enhanced shale gas recovery: Prospect and challenges. Journal of Natural Gas Science and Engineering 77, 103240. injection is a promising technique that not only enhances shale gas recovery but also achieves geological storage of CO2. This paper reviewed the performance of CO2 injection techniques based on simulations and field test studies. We observed that CO2 injection can be practical and successful in a hydraulically fractured shale. The techniques can lead up to 26% more methane production after primary recovery, and sequester more than 60% of the injected CO2 for continuous CO2 injection, while for huff-n-puff higher amount of CO2 is reproduced. Reservoir pressure gradient, competitive adsorption, flow dynamics, and shale properties were found as essential factors controlling CH4 recovery and CO2 storage. Despite the flow dynamics of gases being important for predicting gas production and storage, most simulations described it based on models suitable for well connected fractures and homogenous shale. Moreover, these models are incapable of analyzing fluid flow in stimulated fractures. Future studies on CO2 injection should address the issue of higher CO2 reproduction during the huff-n-puff, the effects of moisture content, induced effects on shale matrix properties by CO2 injection, the kinetics of CO2–CH4 competitive adsorption, flow dynamics of multicomponent gas, and consider the complex pore system of a heterogeneous shale.Imtiazy, M.N., Paterson, A.M., Higgins, S.N., Yao, H., Couture, S., Hudson, J.J., 2020. Dissolved organic carbon in eastern Canadian lakes: Novel patterns and relationships with regional and global factors. Science of The Total Environment 726, 138400. patterns in dissolved organic carbon (DOC) concentrations in 49 eastern Canadian lakes from four sites were re-examined with a ~ 35-year (~1980–2015) dataset. The study sites were Dorset (number of lakes, n = 8), Experimental Lakes Area (ELA, n = 4), Kejimkujik (n = 26) and Yarmouth (n = 11). Lake DOC patterns were synchronous within each site. However, comparisons of DOC patterns across sites showed that they were synchronous only between the Kejimkujik and Yarmouth locations. Hence, these two sites were pooled into a single Nova Scotia site (NS). Increases in DOC concentration were evident in Dorset, Ontario from 1988 (r2 = 0.78, p < 0.001) and NS from 2000 (r2 = 0.43, p = 0.006). DOC at the ELA in northwestern Ontario had a different pattern compared to the other sites, i.e., DOC had increased earlier (1983–2000), and then, unlike Dorset and NS, neither an increase nor decrease was detected between 2001 and 2015 (p = 0.78). Precipitation and sulfur deposition explained the greatest variance in DOC patterns at the Dorset and NS sites (i.e., precipitation: 21–49% and sulfur deposition: 24–54%). Precipitation was the most important driver of DOC at the ELA. Our results indicate that all the sites have gone through a process of increasing DOC, but at different times. The stabilizing pattern at the ELA since 2001 may suggest that DOC concentrations in ELA lakes have reached, or are approaching a new equilibrium, a phenomenon that was not observed at the other sites. Also, the increase in DOC was not always associated with declining sulfur deposition (e.g., ELA). Therefore, we conclude that there was considerable variation in DOC patterns across this large geographic region of Canada and potential drivers of these patterns were not consistent across these diverse sites.Inoue, K., Tsunoda, S.P., Singh, M., Tomida, S., Hososhima, S., Konno, M., Nakamura, R., Watanabe, H., Bulzu, P.-A., Banciu, H.L., Andrei, A.-?., Uchihashi, T., Ghai, R., Béjà, O., Kandori, H., 2020. Schizorhodopsins: A family of rhodopsins from Asgard archaea that function as light-driven inward H+ pumps. Science Advances 6, eaaz2441. (SzRs), a rhodopsin family first identified in Asgard archaea, the archaeal group closest to eukaryotes, are present at a phylogenetically intermediate position between typical microbial rhodopsins and heliorhodopsins. However, the biological function and molecular properties of SzRs have not been reported. Here, SzRs from Asgardarchaeota and from a yet unknown microorganism are expressed in Escherichia coli and mammalian cells, and ion transport assays and patch clamp analyses are used to demonstrate SzR as a novel type of light-driven inward H+ pump. The mutation of a cytoplasmic glutamate inhibited inward H+ transport, suggesting that it functions as a cytoplasmic H+ acceptor. The function, trimeric structure, and H+ transport mechanism of SzR are similar to that of xenorhodopsin (XeR), a light-driven inward H+ pumping microbial rhodopsins, implying that they evolved convergently. The inward H+ pump function of SzR provides new insight into the photobiological life cycle of the Asgardarchaeota.Jahanbani Veshareh, M., Ayatollahi, S., 2020. Microorganisms’ effect on the wettability of carbonate oil-wet surfaces: implications for MEOR, smart water injection and reservoir souring mitigation strategies. Journal of Petroleum Exploration and Production Technology 10, 1539-1550. upstream oil industry, microorganisms arise some opportunities and challenges. They can increase oil recovery through microbial enhanced oil recovery (MEOR) mechanisms, or they can increase production costs and risks through reservoir souring process due to H2S gas production. MEOR is mostly known by bioproducts such as biosurfactant or processes such as bioclogging or biodegradation. On the other hand, when it comes to treatment of reservoir souring, the only objective is to inhibit reservoir souring. These perceptions are mainly because decision makers are not aware of the effect microorganisms’ cell can individually have on the wettability. In this work, we study the individual effect of different microorganisms’ cells on the wettability of oil-wet calcite and dolomite surfaces. Moreover, we study the effect of two different biosurfactants (surfactin and rhamnolipid) in two different salinities. We show that hydrophobe microorganisms can change the wettability of calcite and dolomite oil-wet surfaces toward water-wet and neutral-wet states, respectively. In the case of biosurfactant, we illustrate that the ability of a biosurfactant to change the wettability depends on salinity and its hydrophilic–hydrophobic balance (HLB). In distilled water, surfactin (high HLB) can change the wettability to a strongly water-wet state, while rhamnolipid only changes the wettability to a neutral-wet state (low HLB). In the seawater, surfactin is not able to change the wettability, while rhamnolipid changes the wettability to a strongly water-wet state. These results help reservoir managers who deal with fractured carbonate reservoirs to design a more effective MEOR plan and/or reservoir souring treatment strategy.Jalili, V., Barkhordari, A., Ghiasvand, A., 2020. Bioanalytical applications of microextraction techniques: A review of reviews. Chromatographia 83, 567-577. preparation is a critical step in the separation of target analytes from complex matrices, which can influence the reliability and accuracy of the resulting analysis. Recent trends in sample preparation techniques are directed toward the automation and online coupling of sample preparation units, miniaturization, high efficiency, low costs, and reducing or eliminating solvent consumption. Microextraction techniques (METs) have all these advantages over conventional extraction methods. Thus, the application of METs in the analysis of different analytes from biological samples has increased significantly in recent years. Over time, many review articles have been written, which focus on the advantages, applications, and advances of these techniques for the analysis of various compounds in biological matrices. This paper presents a review of publications pertaining to the application of different types of METs in the analysis of biological samples along with their different aspects and a discussion of their future.Jang, J., Cao, S.C., Stern, L.A., Waite, W.F., Jung, J., Lee, J.Y., 2020. Potential freshening impacts on fines migration and pore-throat clogging during gas hydrate production: 2-D micromodel study with diatomaceous UBGH2 sediments. Marine and Petroleum Geology 116, 104244. methane gas hydrate stored in natural sediments is considered a potential gas resource. Countries such as China, India, Japan, and Korea are interested in commercializing this resource, and offshore field pilot tests for gas production have been conducted using depressurization methods to destabilize gas hydrate and facilitate the migration of methane to the production well. However, fine-grained sediments (fines), which are present even in coarse-grained, gas hydrate-bearing sediments, can be resuspended in the production fluid, subsequently clogging pore throats in the formation and reducing the overall production efficiency. We conducted laboratory tests to evaluate the suspension and clogging potential of fines collected from the Ulleung Basin, East Sea, Korea during the 2010 Ulleung Basin Gas Hydrate Expedition 2 (UBGH2). Experimental results reveal that diatoms are prevalent in the sediment and largely control the suspension and clogging behavior. Fluid flow experiments in 2D micromodels show clogging occurs even when injecting the minimum sediment concentration (0.1?wt% in the fluid) through micromodels with pore-throat widths at the high end of the anticipated range for UBGH2 gas hydrate-bearing sands (100?μm). Mobile gas/fluid interfaces forming during gas hydrate dissociation accentuate clogging by concentrating and mobilizing fines. Sedimentation tests show pore-water freshening during dissociation is not anticipated to change the potential for diatoms to become entrained in the pore water flow, even for the observed gas hydrate saturations of ~80%. Muscovite and illite are also significant components of the tested sediment, however, and pore-water freshening increases their potential for resuspension and clogging. Overall, the resuspension and clogging potential of these fine sediments should increase as gas hydrate dissociation progresses in the thin, gas hydrate-bearing sands investigated in the Ulleung Basin.Jang, Y., Bang, J., Seon, Y.-S., You, D.-W., Oh, J.-S., Jung, K.-W., 2020. Carbon nanotube sponges as an enrichment material for aromatic volatile organic compounds. Journal of Chromatography A 1617, 460840. methods are required for in situ monitoring of volatile organic compounds (VOCs). Herein, carbon nanotube (CNT) sponges were investigated as a new type of adsorbent for enriching trace aromatic VOCs. A square pillar configuration (3 mm × 3 mm × 45 mm, 5 mg) of a CNT sponge was enclosed in a glass tube (4 mm i.d.). After accumulating the sample vapor, a direct current pulse (26 V, 0.5–3.0 s) through the CNT sponge allowed narrow desorption bandwidths of 0.48?0.84 s (with a photoionization detector) and 1.2 s (with a flame ionization detector) and high desorption efficiency (>96.5%). Gas chromatographic analysis of a nine-component VOC mixture (100 mL adsorption volume) gave enrichment factors of 88 (benzene) to 323 (toluene and m-xylene) with detection limits in the range of 0.9?2.6 ppb (v/v). These results demonstrate that CNT sponges are a promising preconcentrator material for trace detection of VOCs. The adsorption breakthrough experiments exhibited good correlation with the kinetic adsorption and Langmuir isotherm models. The maximum adsorption capacities of the CNT sponge increased in the order benzene (0.13 mg/g) < toluene (2.45 mg/g) < ethylbenzene (13.90 mg/g) < o-xylene (14.31 mg/g), with R2 values of >0.95. The rollup phenomena observed during multicomponent adsorption were explained by the competitive displacement or adsorption affinities of aromatic VOCs. The feasibility of the CNT sponge preconcentrator in a real environment was tested for interfering species (NO2 and NH3), laboratory air, and a human breath sample and demonstrated similar performance as in the controlled nine-component tests.Jansen, J., Thornton, B.F., Cortés, A., Sn??lv, J., Wik, M., MacIntyre, S., Crill, P.M., 2020. Drivers of diffusive CH4 emissions from shallow subarctic lakes on daily to multi-year timescales. Biogeosciences 17, 1911-1932. and reservoirs contribute to regional carbon budgets via significant emissions of climate forcing trace gases. Here, for improved modelling, we use 8 years of floating chamber measurements from three small, shallow subarctic lakes (2010–2017, n=1306) to separate the contribution of physical and biogeochemical processes to the turbulence-driven, diffusion-limited flux of methane (CH4) on daily to multi-year timescales. Correlative data include surface water concentration measurements (2009–2017, n=606), total water column storage (2010–2017, n=237), and in situ meteorological observations. We used the last to compute near-surface turbulence based on similarity scaling and then applied the surface renewal model to compute gas transfer velocities. Chamber fluxes averaged 6.9±0.3?mg CH4?m?2?d?1 and gas transfer velocities (k600) averaged 4.0±0.1?cm?h?1. Chamber-derived gas transfer velocities tracked the power-law wind speed relation of the model. Coefficients for the model and dissipation rates depended on shear production of turbulence, atmospheric stability, and exposure to wind. Fluxes increased with wind speed until daily average values exceeded 6.5?m?s?1, at which point emissions were suppressed due to rapid water column degassing reducing the water–air concentration gradient. Arrhenius-type temperature functions of the CH4 flux (E ′ a =0.90±0.14 ?eV) were robust (R2≥0.93, p<0.01) and also applied to the surface CH4 concentration (E ′ a =0.88±0.09 ?eV). These results imply that emissions were strongly coupled to production and supply to the water column. Spectral analysis indicated that on timescales shorter than a month, emissions were driven by wind shear whereas on longer timescales variations in water temperature governed the flux. Long-term monitoring efforts are essential to identify distinct functional relations that govern flux variability on timescales of weather and climate change.Jarvis, B.M., Lehrter, J.C., Lowe, L.L., Hagy, J.D., Wan, Y., Murrell, M.C., Ko, D.S., Penta, B., Gould Jr, R.W., 2020. Modeling spatiotemporal patterns of ecosystem metabolism and organic carbon dynamics affecting hypoxia on the Louisiana continental shelf. Journal of Geophysical Research: Oceans 125, e2019JC015630.: The hypoxic zone on the Louisiana Continental Shelf (LCS) forms each summer due to nutrient‐enhanced primary production and seasonal stratification associated with freshwater discharges from the Mississippi/Atchafalaya River Basin (MARB). Recent field studies have identified highly productive shallow nearshore waters as an important component of shelf‐wide carbon production contributing to hypoxia formation. This study applied a three‐dimensional hydrodynamic‐biogeochemical model named CGEM (Coastal Generalized Ecosystem Model) to quantify the spatial and temporal patterns of hypoxia, carbon production, respiration, and transport between nearshore and middle shelf regions where hypoxia is most prevalent. We first demonstrate that our simulations reproduced spatial and temporal patterns of carbon production, respiration, and bottom‐water oxygen gradients compared to field observations. We used multiyear simulations to quantify transport of particulate organic carbon (POC) from nearshore areas where riverine organic matter and phytoplankton carbon production are greatest. The spatial displacement of carbon production and respiration in our simulations was created by westward and offshore POC flux via phytoplankton carbon flux in the surface layer and POC flux in the bottom layer, supporting heterotrophic respiration on the middle shelf where hypoxia is frequently observed. These results support existing studies suggesting the importance of offshore carbon flux to hypoxia formation, particularly on the west shelf where hypoxic conditions are most variable.Plain Language Summary: Formation of hypoxia, or low dissolved oxygen, is a seasonal occurrence on the Louisiana Continental Shelf associated with stratification of the water column and excess nutrient loads delivered via the Mississippi and Atchafalaya River systems. Frequently referred to as “dead zones,” bottom‐water hypoxia results in stress or death of aquatic organisms, especially those that cannot move to areas with more oxygen. To study the sources and distribution of organic matter that supports oxygen consumption, we applied a three‐dimensional hydrodynamic‐biogeochemical model named CGEM (Coastal Generalized Ecosystem Model). CGEM simulations between 2003 and 2007 successfully simulated spatial and temporal patterns of hypoxia and important biological processes that control its formation. Our simulations revealed that highly productive nearshore waters serve as a source of organic matter that supports oxygen consumption offshore. We identified seasonal bottom‐layer currents that transport organic matter offshore and interannual variations in river discharge that influence biological production and bottom‐layer oxygen consumption offshore. The ecological processes described in this study increase our understanding of how nearshore processes affect the development and maintenance of offshore hypoxia.Jiang, T., Han, J., Wu, G., Yu, H., Su, Z., Xiong, C., Chen, J., Zhang, H., 2020. Differences and controlling factors of composite hydrocarbon accumulations in the Tazhong uplift, Tarim Basin, NW China. Petroleum Exploration and Development 47, 229-241. on three-dimensional seismic interpretation, structural and sedimentary feature analysis, and examination of fluid properties and production dynamics, the regularity and main controlling factors of hydrocarbon accumulation in the Tazhong uplift, Tarim Basin are investigated. The results show that the oil and gas in the Tazhong uplift has the characteristics of complex accumulation mainly controlled by faults, and more than 80% of the oil and gas reserves are enriched along fault zones. There are large thrust and strike-slip faults in the Tazhong uplift, and the coupling relationship between the formation and evolution of the faults and accumulation determine the difference in complex oil and gas accumulations. The active scale and stage of faults determine the fullness of the traps and the balance of the phase, that is, the blocking of the transport system, the insufficient filling of oil and gas, and the unsteady state of fluid accumulation are dependent on the faults. The multi-period tectonic sedimentary evolution controls the differences of trap conditions in the fault zones, and the multi-phase hydrocarbon migration and accumulation causes the differences of fluid distribution in the fault zones. The theory of differential oil and gas accumulation controlled by fault is the key to the overall evaluation, three-dimensional development and discovery of new reserves in the Tazhong uplift.Jiménez-Arias, J.L., Morris, E., Rubio-de-Inglés, M.J., Peralta, G., García-Robledo, E., Corzo, A., Papaspyrou, S., 2020. Tidal elevation is the key factor modulating burial rates and composition of organic matter in a coastal wetland with multiple habitats. Science of The Total Environment 724, 138205. study examines long-term burial rates of organic carbon (OC), organic nitrogen (ON), and total sulphur (TS) in a tidal-dominated coastal wetland with a high spatial heterogeneity and habitat diversity, and long history of human impacts, Cádiz Bay (SW Spain). Using replicate sediment cores, we quantified fluxes of these elements over a transect, extending from the lower saltmarsh (Spartina maritima, ~0.3?m mean sea level, MSL) to the lower intertidal region (Zostera noltei, ~???0.7?m MSL). Potential organic matter (OM) sources to the sediment were examined using an extensive dataset on carbon and nitrogen stable isotopes, and C:N molar ratios of primary producers in the region. OC burial rates decreased from the sites below MSL (~80 gC·m?2·y?1) to the lower saltmarsh (~50 gC·m?2·y?1), whereas ON burial rates showed an opposite pattern (~3 gN·m?2·y?1 and ~4 gN·m?2·y?1 observed below and above MSL, respectively). TS burial rates (0.5–46 gS·m?2·y?1) did not show any trend along the sea-land gradient. Hence, (tidal) elevation appeared to be an important determinant of sediment biogeochemical properties, and predictor of OM burial rates. The Bayesian mixing model suggested a well-mixed combination of subtidal and terrestrial/high-marsh OM sources to the surface sediments, with no clear indication of an increased contribution from the particular vegetation species inhabiting the sediments. The indication that there is substantial transport, remineralization and cycling of OM between habitats, suggests diversity may play an important role in maintaining this function, reinforcing the idea that a holistic, catchment-scale view is appropriate for understanding and preserving the long-term burial of OM in coastal wetlands.Jiménez-González, M.A., Almendros, G., Waggoner, D.C., ?lvarez, A.M., Hatcher, P.G., 2020. Assessment of the molecular composition of humic acid as an indicator of soil carbon levels by ultra-high-resolution mass spectrometric analysis. Organic Geochemistry 143, 104012. stabilization of soil organic matter (SOM) plays an important role in the carbon cycle. Hence, understanding biogeochemical mechanisms of soil C sequestration is crucial to control its release to the atmosphere. This study aims at investigating the biogeochemical mechanisms of soil C sequestration. An exploratory assessment was carried out on the information about the soil C levels provided by the molecular composition of humic acids (HAs) analyzed by electrospray ionization (ESI) Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS). Significant PLS forecasting model for total soil C was obtained using as descriptors the 131 compounds in common in all the HAs detected by FTICR-MS, and its variable importance for projection (VIP) was plotted in the space defined by their atomic ratios using van Krevelen diagrams. The results indicated that significant relationships exist between the HAs molecular composition and the soil organic C levels. The VIP values for the different groups of compounds illustrates how HA contains information about the amounts of C stored in the soil: the HAs in the soils with high levels of organic C have significantly (P < 0.1) higher proportions of unsaturated lipid and lignin-derived compounds; on the other side, low soil organic C levels are associated to HAs with comparatively high proportions of saturated lipid compounds.Joy, K.H., Tartèse, R., Messenger, S., Zolensky, M.E., Marrocchi, Y., Frank, D.R., Kring, D.A., 2020. The isotopic composition of volatiles in the unique Bench Crater carbonaceous chondrite impactor found in the Apollo 12 regolith. Earth and Planetary Science Letters 540, 116265. striking the Moon have modified its crust and delivered volatile elements to its interior and surface. Direct evidence of impactor origins is recorded by the rare occurrence of sub-cm sized meteorite fragments identified in Apollo samples and lunar meteorites. The Bench Crater meteorite is a millimetre-sized carbonaceous chondrite collected in regolith on the rim of Bench impact crater at the Apollo 12 landing site. Transmission electron microscopy has previously shown that Bench Crater contains abundant hydrated silicates, establishing the survivability of hydrated material impacting the lunar surface. To provide further information on the volatile inventory of the Bench Crater meteorite, we report here the isotope compositions of hydrogen, nitrogen, carbon and oxygen. This is the first direct isotopic analysis of meteoritic material delivered to the lunar surface and provides context for volatile and organic element signatures in lunar regolith samples, and the survivability of volatile material delivered to planetary surfaces during impact bombardment. The Bench Crater meteorite is characterised by δD values ranging between ?36 ± 40 and 200 ± 40‰, and bulk average δ13C of ?13 ± 30‰, and δ15N of ?40 ± 36‰ (all uncertainties at the 2σ confidence level). The oxygen isotope compositions measured in situ in matrix silicates and magnetite in Bench Crater are consistent with those measured in matrix and magnetite in CI and CM chondrite falls. Altogether, these new H, C, N and O isotope data, coupled to mineralogical and geochemical observations, suggest that Bench Crater may have been derived from an asteroidal parent body not represented in the terrestrial meteorite collection. This is a crucial outcome in the current context of sample-return missions to carbonaceous asteroids, and more broadly for investigating the flux of material delivered to the Earth-Moon system through time.Ju, X., Liu, F., Fu, P., White, M.D., Settgast, R.R., Morris, J.P., 2020. Gas production from hot water circulation through hydraulic fractures in methane hydrate-bearing sediments: THC-coupled simulation of production mechanisms. Energy & Fuels 34, 4448-4465. hydrates, widely found in permafrost and deep marine sediments, have great potential as a future energy source. Conventional production schemes perform poorly for challenging hydrate reservoirs with low permeability. We propose an efficient production scheme by combining hydraulic fracturing from horizontal wells and hot water circulation through fractures. A fully coupled thermo-hydro-chemical (THC) model is developed to simulate the key physical processes during gas production from a hydrate reservoir representative of typical geological settings in Shenhu, South China Sea. We found that the gas production process has two distinct stages divided by thermal breakthrough: a relatively short prebreakthrough stage and a postbreakthrough stage yielding stable gas production. Heat advection along and near the hydraulic fracture dominates the prebreakthrough stage, whereas conduction-driven thermal recovery in the volume around fractures dominates the postbreakthrough stage. We identified that the steady-state injection temperature has a strong effect on the performance of the proposed scheme while the fluid mass circulation rate has a moderate impact beyond a threshold. The proposed scheme proves to be efficient and robust over a range of reservoir conditions with respect to initial hydrate saturation and intrinsic permeability, including their spatial heterogeneities, thereby offering a promising solution for challenging reservoir conditions.Ju, Y., Gilfillan, S.M.V., Lee, S.-S., Kaown, D., Hahm, D., Lee, S., Park, I.-W., Ha, S.-W., Park, K., Do, H.-K., Yun, S.-T., Lee, K.-K., 2020. Application of noble gas tracers to identify the retention mechanisms of CO2 migrated from a deep reservoir into shallow groundwater. International Journal of Greenhouse Gas Control 97, 103041. Capture and Storage (CCS) is a valuable climate-mitigation technology, which offers the potential to cost-effectively reduce the emissions associated with the burning of fossil fuels. However, there is a potential risk of a small portion of the stored CO2 unintentionally migrating from a storage site to a shallow groundwater aquifer which is the final retaining zone for any migrated CO2 before it escapes to the atmosphere. Hence, it is imperative to identify the physical retention mechanisms of CO2 within a shallow aquifer. In this study 1.70?×?102 kg of CO2 and noble gas tracers (He, Ar and Kr) were continuously injected into a groundwater aquifer over 28 days with the aim of identifying the mechanisms and amount of CO2 retention. Among the tracers, Kr was found to be the earliest indicator of CO2 migration. The other tracers – He and Ar – arrived later and exhibited diluted signals. The diluted signals were attributed to degassing of the plume mass (1.6 % of CO2) during the early stages of CO2 migration. Diffusion accelerated the dilution of the lighter elements at the plume boundaries. Consequently, the clear relation of the noble gases with the CO2 proved that degassing and mixing primarily control the mass retention of CO2 in shallow groundwater, and the relative importance of these processes varies along the evolving path of migrating CO2.Kajita, H., Nakamura, H., Ohkouchi, N., Harada, N., Sato, M., Tokioka, S., Kawahata, H., 2020. Genomic and geochemical identification of the long-chain alkenone producers in the estuarine Lake Takahoko, Japan: Implications for temperature reconstructions. Organic Geochemistry 142, 103980. the lacustrine haptophyte species that produce long-chain alkenones (LCAs) is essential for using alkenone unsaturation ratios to create lake water temperature reconstructions. We discovered LCAs in the brackish Lake Takahoko in northern Japan. The identity of LCA-producing species was investigated using 18S ribosomal DNA (rDNA) and organic geochemical analysis. Two distinct genetic groups, termed Tak-A and Tak-B, were identified within the Group II haptophyte phylotype. Tak-A was closely related to Hap-A, which was obtained from Lake George, USA; and Tak-B was identified as Isochrysis galbana. Because Hap-A and Isochrysis galbana have similar temperature calibrations, Tak-A and Tak-B were also expected to share similar calibrations. Therefore, the changes of their relative abundances in the lake should not significantly disturb paleotemperature reconstructions. The alkenone temperature recorded in the surface sediment corresponded to the lake temperature in early to late summer. This is likely related to the haptophyte bloom season in Lake Takahoko suggesting that this lake may be a viable location for creating a lacustrine alkenone paleotemperature record.Kamalanathan, M., Doyle, S.M., Xu, C., Achberger, A.M., Wade, T.L., Schwehr, K., Santschi, P.H., Sylvan, J.B., Quigg, A., 2020. Exoenzymes as a signature of microbial response to marine environmental conditions. mSystems 5, e00290-20.: Microbial heterotopic metabolism in the ocean is fueled by a supply of essential nutrients acquired via exoenzymes catalyzing depolymerization of high-molecular-weight compounds. Although the rates of activity for a variety of exoenzymes across various marine environments are well established, the factors regulating the production of these exoenzymes, and to some extent their correlation with microbial community composition, are less known. This study focuses on addressing these challenges using a mesocosm experiment that compared a natural seawater microbial community (control) and exposed (to oil) treatment. Exoenzyme activities for β-glucosidase, leucine aminopeptidase (LAP), and lipase were significantly correlated with dissolved nutrient concentrations. We measured correlations between carbon- and nitrogen-acquiring enzymes (β-glucosidase/lipase versus LAP) and found that the correlation of carbon-acquiring enzymes varies with the chemical nature of the available primary carbon source. Notably, a strong correlation between particulate organic carbon and β-glucosidase activity demonstrates their polysaccharide depolymerization in providing the carbon for microbial growth. Last, we show that exoenzyme activity patterns are not necessarily correlated with prokaryotic community composition, suggesting a redundancy of exoenzyme functions among the marine microbial community and substrate availability. This study provides foundational work for linking exoenzyme function with dissolved organic substrate and downstream processes in marine systems.Importance: Microbes release exoenzymes into the environment to break down complex organic matter and nutrients into simpler forms that can be assimilated and utilized, thereby addressing their cellular carbon, nitrogen, and phosphorus requirements. Despite its importance, the factors associated with the synthesis of exoenzymes are not clearly defined, especially for the marine environment. Here, we found that exoenzymes associated with nitrogen and phosphorus acquisition were strongly correlated with inorganic nutrient levels, while those associated with carbon acquisition depended on the type of organic carbon available. We also show a linear relationship between carbon- and nitrogen-acquiring exoenzymes and a strong correlation between microbial biomass and exoenzymes, highlighting their significance to microbial productivity. Last, we show that changes in microbial community composition are not strongly associated with changes in exoenzyme activity profiles, a finding which reveals a redundancy of exoenzyme activity functions among microbial community. These findings advance our understanding of previously unknown factors associated with exoenzyme production in the marine environment.Kates, L.N., Richards, P.I., Sandau, C.D., 2020. The application of comprehensive two-dimensional gas chromatography to the analysis of wildfire debris for ignitable liquid residue. Forensic Science International 310, 110256. wildfires are complex investigations due to the high abundance of natural background compounds and subsequent pyrolysis by-products formed during combustion. These interfering compounds can be present in large concentrations and overwhelm the marker compounds used to identify ignitable liquid residue (ILR). Complex matrix effects often interfere with the identification of ILR, providing ambiguous results. The use of comprehensive two-dimensional gas chromatography with time of flight mass spectrometry (GC?×?GC-TOFMS) separates natural compounds from interfering with ILR compounds of interest. When compared to standard gas chromatography-mass spectrometry (GC-MS) analysis, GC?×?GC was able to reduce the number of tentative results by 20%. Certain compounds were determined to be unusable for the identification of ILR in wildfire debris samples, in particular the Three Musketeer Group (Ethylbenzene, m,p-Xylene, and o-Xylene), which are ubiquitous in all samples, as well as long chain n-alkylbenzenes, which are formed in the pyrolysis of organic matter. Conversely, the presence of C1- and C2-alkylnaphthalenes were excellent indicators of the presence of gasoline-type ILR. A sizeable number of background samples were collected that helped to provide additional lines of evidence when classifying samples for ILR. Given the complicated matrices encountered in arsonous wildfires, it is evident that GC?×?GC provides better capabilities at identifying ILR than the standard GC-MS analytical technique.Kaufmann, A., Butcher, P., Maden, K., Walker, S., Widmer, M., 2020. Does the ion mobility resolving power as provided by commercially available ion mobility quadrupole time-of-flight mass spectrometry instruments permit the unambiguous identification of small molecules in complex matrices? Analytica Chimica Acta 1107, 113-126. based mass spectrometry based detection has experienced enormous improvements in terms of sensitivity over the last centuries. This development has not been equally matched with improvements in selectivity. Hence, the use of unit mass based MS/MS transitions or high resolution (HRMS) based extracted ion chromatograms is gradually becoming insufficient in the field of high sensitivity multi-residue analysis (e.g. pesticides in food). As a consequence, commercial instruments hyphenating ion mobility (IMS) with low or high resolution mass spectrometry based detection have appeared. The use of such an additional (frequently claimed to be orthogonal) dimension is intended to increase selectivity. In addition, IMS derived collision cross section (CCS) has been proposed to be used as an additional identification point for the unambiguous identification of trace compounds in complex matrices.It is the topic of this paper to investigate the benefit of using such a hyphenated technique for trace analysis of small molecules in complex matrices. The potential of CCS to serve as additional identification point has been critically evaluated. Discussed are the effect of CCS data on false detects and missing detects of analytes present at trace levels. This involves the investigation of the physical resolving power provided by HRMS, IMS and chromatography as well as the correlation among these parameters (orthogonality).It is the conclusion that currently commercially available travelling wave and linear drift tube based IMS devices with a resolving power of up to 50 permit a reduction of false detects, yet this comes at the price of a higher likelihood of missing detects. The reduction of missing detects and the use of CCS as potential confirmatory information would require IMS resolving powers above 100.Khaleel, A.T., Abutaqiya, M.I.L., Sisco, C.J., Vargas, F.M., 2020. Mitigation of asphaltene deposition by re-injection of dead oil. Fluid Phase Equilibria 514, 112552. deposition is a common flow assurance problem in the oil and gas industry. During oil production, changes in pressure, temperature, and composition may induce precipitation as asphaltenes become unstable in the oil. Precipitated asphaltenes can then deposit on the inner walls of the production tubing and restrict or even completely block the flow of oil. In this work, we propose a novel chemical-free technique to mitigate asphaltene deposition, where dead oil collected at the surface is recycled to reduce asphaltene precipitation. The stabilization effect of the dead oil reinjection is investigated from a thermodynamic perspective using PC-SAFT EOS. Four crude oils from the literature are investigated, and it is found that the asphaltene unstable region and precipitated amounts reduce significantly upon reinjection of dead oil. The simulation results suggest that, depending on the amount of reinjection and the oil characteristics, asphaltene precipitation can be eliminated by simply reinjecting dead oil.Khodja, F.A., Sassiat, P., Hanafi, M., Thiebaut, D., Vial, J., 2020. A promising "metastable" liquid crystal stationary phase for gas chromatography. Journal of Chromatography A 1616, 460786. liquid crystal state is an ordered physical state between a solid and a liquid. Previous research, in gas chromatography, proved that it provides a geometric selectivity, which allows the separation of geometric position isomers and cis-trans isomers that are difficult to separate on conventional gas chromatography stationary phases (polydimethyl siloxane derived and polyethylene glycol stationary phases). However, their use was generally very limited by the rather high temperature at which they must be operated, normally above the solid-liquid crystal transition temperature. In the present study we are interested in a new synthesized material, 1,4- bis (4-bromohexyloxy benzoate) phenyl (BHOBP). The first characterizations of BHOBP were carried out by thermogravimetric analysis, hot-stage optical microscopy and differential scanning calorimetry to control the thermal stability of the BHOBP as well as the nematic texture of the mesophase highlighted in a well-defined temperature range (120°C-200°C). When heated, the solid compound led to a stable liquid crystal state. Its cooling has revealed "a new metastable physical state, which is the supercooled liquid crystal phase". After these first characterizations, the new material was used as a stationary phase for gas chromatography. The BHOBP was deposited in a capillary column by the dynamic method. The inverse gas chromatography study of the column revealed a solid-stable nematic phase transition temperature, in agreement with the first characterization methods. The stable liquid crystal phase showed good resolutions in the analysis of some geometric isomers of low volatility as PAHs. The presence of the supercooled liquid crystal state in the chromatographic column has also been confirmed. This new metastable state is particularly interesting because it enlarged the scope of this material by improving the resolution of several mixtures. Thus, the separation of highly volatile mixtures of geometric isomers (e.g. cis and trans-decalin) was achieved only through this metastable mesophase confirming its unique selectivity. The metastable liquid crystal, used at 80°C, has also exhibited an original behavior by its stability after several weeks of use at the same temperature, maintaining constant retention factors and selectivity.Khosravi, R., Rodriguez, C., Mostowfi, F., Sieben, V., 2020. Evaluation of crude oil asphaltene deposition inhibitors by surface plasmon resonance. Fuel 273, 117787. present a direct method for evaluating the effectiveness of inhibitors on asphaltene deposition from crude oil based on a Kretschmann configuration surface plasmon resonance (SPR) sensor. We demonstrate that shifts in the peak SPR wavelength during titration experiments can be used to compare inhibitors, both by changes to the deposition temporal profile and by changes to the refractive index of the final deposit. We continually measure the SPR peak wavelength throughout the entire titration experiment, starting with that of the neat crude oil and gradually ramping through a pre-defined range of n-heptane to crude oil fractions. After the deposition onset point, asphaltenes precipitate and are deposited onto the sensing surface, which results in an SPR peak wavelength increase as the refractive index of the deposit on the sensing surface increases. The asphaltenes continue to deposit on the surface until the deposit completely fills the SPR field penetration depth. We observe a change in the asphaltene deposition profile and also the final average refractive index of the deposit when inhibitors are added to the neat crude oil and the same titration experiment is conducted. We also qualitatively describe the asphaltene deposition mechanism using SPR spectral data. SPR provides a new and powerful sensing approach for screening and comparing the effectiveness of asphaltene deposition inhibitors.Kim, Y.J., Yang, J.-A., Lim, J.K., Park, M.-J., Yang, S.-H., Lee, H.S., Kang, S.G., Lee, J.-H., Kwon, K.K., 2020. Paradesulfovibrio onnuriensis gen. nov., sp. nov., a chemolithoautotrophic sulfate-reducing bacterium isolated from the Onnuri vent field of the Indian Ocean and reclassification of Desulfovibrio senegalensis as Paradesulfovibrio senegalensis comb. nov. Journal of Microbiology 58, 252-259. anaerobic, rod-shaped, mesophilic, chemolithoautotrophic, sulfate-reducing bacterial strain IOR2T was isolated from a newly found deep-sea hydrothermal vent (OVF, Onnuri Vent Field) area in the central Indian Ocean ridge (11°24′88″ S 66°25′42″ E, 2021 m water depth). The 16S rRNA gene sequence analysis revealed that the strain IOR2T was most closely related to Desulfovibrio senegalensis BLaC1T (96.7%). However, it showed low similarity with the members of the family Desulfovibrionaceae, such as Desulfovibrio tunisiensis RB22T (94.0%), D. brasiliensis LVform1T (93.9%), D. halophilus DSM 5663T (93.7%), and Pseudodesulfovibrio aespoeensis Aspo-2T (93.2%). The strain IOR2T could grow at 23–42°C (optimum 37°C), pH 5.0–8.0 (optimum pH 7.0) and with 0.5–6.5% (optimum 3.0%) NaCl. The strain could use lactate, pyruvate, H2, and glycerol as electron donors and sulfate, thiosulfate, and sulfite as electron acceptors. The major fatty acids of the strain IOR2T were iso-C15:0, iso-C17:0, ante-iso-C15:0, and summed feature 9 (C16:0 methyl/iso-C17:1ω9c). Both the strains IOR2T and BLaC1T could grow with CO2 and H2 as the sole sources of carbon and energy, respectively. Genomic evidence for the Wood-Ljungdahl pathway in both the strains reflects chemolithoautotrophic growth. The DNA G + C content of the strain IOR2T and BLaC1T was 58.1–60.5 mol%. Based on the results of the phylogenetic and physiologic studies, Paradesulfovibrio onnuriensis gen. nov., sp. nov. with the type strain IOR2T (= KCTC 15845T = MCCC 1K04559T) was proposed to be a member of the family Desulfovibrionaceae. We have also proposed the reclassification of D. senegalensis as Paradesulfovibrio senegalensis comb. nov.Kimura, M., Akanuma, S., 2020. Reconstruction and characterization of thermally stable and catalytically active proteins comprising an alphabet of?~?13 amino acids. Journal of Molecular Evolution 88, 372-381. extant organisms synthesize proteins using approximately 20 kinds of genetically coded amino acids, the earliest protein synthesis system is likely to have been much simpler, utilizing a reduced set of amino acids. However, which types of building blocks were involved in primordial protein synthesis remains unclear. Herein, we reconstructed three convergent sequences of an ancestral nucleoside diphosphate kinase, each comprising a 10 amino acid “alphabet,” and found that two of these variants folded into soluble and stable tertiary structures. Therefore, an alphabet consisting of 10 amino acids contains sufficient information for creating stable proteins. Furthermore, re-incorporation of a few more amino acid types into the active site of the 10 amino acid variants improved the catalytic activity, although the specific activity was not as high as that of extant proteins. Collectively, our results provide experimental support for the idea that robust protein scaffolds can be built with a subset of the current 20 amino acids that might have existed abundantly in the prebiotic environment, while the other amino acids, especially those with functional sidechains, evolved to contribute to efficient enzyme catalysis.Kirtzel, J., Ueberschaar, N., Deckert-Gaudig, T., Krause, K., Deckert, V., Gadd, G.M., Kothe, E., 2020. Organic acids, siderophores, enzymes and mechanical pressure for black slate bioweathering with the basidiomycete Schizophyllum commune. Environmental Microbiology 22, 1535-1546. many fungi are known to be able to perform bioweathering of rocks and minerals, little information is available concerning the role of basidiomycetes in this process. The wood‐rotting basidiomycete Schizophyllum commune was investigated for its ability to degrade black slate, a rock rich in organic carbon. Mechanical pressure of hyphae and extracellular polymeric substances was investigated for biophysical weathering. A mixed ?1‐3/?1‐6 glucan, likely schizophyllan that is well known from S. commune, could be identified on black slate surfaces. Secretion of siderophores and organic acids as biochemical weathering agents was shown. Both may contribute to biochemical weathering in addition to enzymatic functions. Previously, the exoenzyme laccase was believed to attack organic the matter within the black slate, thereby releasing metals from the rock. Here, overexpression of laccase showed enhanced dissolution of quartz phases by etching and pitting. At the same time, the formation of a new secondary mineral phase, whewellite, could be demonstrated. Hence, a more comprehensive understanding of biophysical as well as biochemical weathering by S. commune could be reached and unexpected mechanisms like quartz dissolution linked to shale degradation.Klages, J.P., Salzmann, U., Bickert, T., Hillenbrand, C.-D., Gohl, K., Kuhn, G., Bohaty, S.M., Titschack, J., Müller, J., Frederichs, T., Bauersachs, T., Ehrmann, W., van de Flierdt, T., Pereira, P.S., Larter, R.D., Lohmann, G., Niezgodzki, I., Uenzelmann-Neben, G., Zundel, M., Spiegel, C., Mark, C., Chew, D., Francis, J.E., Nehrke, G., Schwarz, F., Smith, J.A., Freudenthal, T., Esper, O., P?like, H., Ronge, T.A., Dziadek, R., Afanasyeva, V., Arndt, J.E., Ebermann, B., Gebhardt, C., Hochmuth, K., Küssner, K., Najman, Y., Riefstahl, F., Scheinert, M., the Science Team of Expedition PS104, 2020. Temperate rainforests near the South Pole during peak Cretaceous warmth. Nature 580, 81-86. mid-Cretaceous period was one of the warmest intervals of the past 140 million years, driven by atmospheric carbon dioxide levels of around 1,000 parts per million by volume6. In the near absence of proximal geological records from south of the Antarctic Circle, it is disputed whether polar ice could exist under such environmental conditions. Here we use a sedimentary sequence recovered from the West Antarctic shelf—the southernmost Cretaceous record reported so far—and show that a temperate lowland rainforest environment existed at a palaeolatitude of about 82° S during the Turonian–Santonian age (92 to 83 million years ago). This record contains an intact 3-metre-long network of in situ fossil roots embedded in a mudstone matrix containing diverse pollen and spores. A climate model simulation shows that the reconstructed temperate climate at this high latitude requires a combination of both atmospheric carbon dioxide concentrations of 1,120–1,680 parts per million by volume and a vegetated land surface without major Antarctic glaciation, highlighting the important cooling effect exerted by ice albedo under high levels of atmospheric carbon dioxide.Kloko?ník, J., Kosteleck?, J., Bezděk, A., Kletetschka, G., Staňková, H., 2020. A 200?km suspected impact crater Kotuykanskaya near Popigai, Siberia, in the light of new gravity aspects from EIGEN 6C4, and other data. Scientific Reports 10, 6093. provide arguments in favour of impact origin of a 200?km suspected impact crater Kotuykanskaya near Popigai, Siberia, Russia. We use the gravity aspects (gravity disturbances, the Marussi tensor of the second derivatives of the disturbing geopotential, the gravity invariants and their specific ratio, the strike angles and the virtual deformations), all derived from the combined static gravity field model EIGEN 6C4, with the ground resolution of about 10?km and a precision of about 10 milliGals. We also use the magnetic anomalies from the model EMAG2 and emphasize the evidence of much deeper sources in the suspected area, constraining the impact origin of this structure.Koike, M., Nakada, R., Kajitani, I., Usui, T., Tamenori, Y., Sugahara, H., Kobayashi, A., 2020. In-situ preservation of nitrogen-bearing organics in Noachian Martian carbonates. Nature Communications 11, 1988. the origin of organic material on Mars is a major issue in modern planetary science. Recent robotic exploration of Martian sedimentary rocks and laboratory analyses of Martian meteorites have both reported plausible indigenous organic components. However, little is known about their origin, evolution, and preservation. Here we report that 4-billion-year-old (Ga) carbonates in Martian meteorite, Allan Hills 84001, preserve indigenous nitrogen(N)-bearing organics by developing a new technique for high-spatial resolution in situ N-chemical speciation. The organic materials were synthesized locally and/or delivered meteoritically on Mars during Noachian age. The carbonates, alteration minerals from the Martian near-surface aqueous fluid, trapped and kept the organic materials intact over long geological times. This presence of N-bearing compounds requires abiotic or possibly biotic N-fixation and ammonia storage, suggesting that early Mars had a less oxidizing environment than today.Kordella, S., Ciotoli, G., Dimas, X., Papatheodorou, G., Etiope, G., 2020. Increased methane emission from natural gas seepage at Katakolo Harbour (Western Greece). Applied Geochemistry 116, 104578. gas seepage in petroleum-bearing sedimentary basins is an important natural source of atmospheric methane. In methane budget models geological emissions are generally considered constant over time, not affecting decadal atmospheric methane changes. Here, we report the case of a considerable sub-decadal variation of methane seepage from one of the largest thermogenic gas seep sites in Europe, Katakolo Harbour (Western Peloponnese, Greece). Based on gas flux measurements by accumulation chamber performed in 2010 and 2018, methane emission from cracks and fissures throughout the asphalt and concrete pavement of the harbour increased about four times (from 57 to 225 kg d?1) with emission factor changing from ~4,000 to 15,000 t km?2 y?1. Multiple lines of evidence, including mechanical deformation and fissuring of concrete and asphalt pavement, increased exhalation with constant fissure conditions, and no significant cracking with operating corrosion from 2004 to 2010, suggest that the methane emission increase is mainly due to intensification of subsurface gas flow (seepage) after 2010. Deep gas pressure and fault permeability variations, likely induced by the numerous earthquakes of the region, might have played a role. We estimate that if similar short-term variations of emission factor occur in large seepage areas worldwide, the global geological methane emission can significantly change, contributing to decadal changes of atmospheric methane budget.Kotapati, H.K., Bates, P.D., 2020. Normal phase HPLC method for combined separation of both polar and neutral lipid classes with application to lipid metabolic flux. Journal of Chromatography B 1145, 122099. normal phase HPLC methods were produced to separate lipid classes on a PVA-Sil stationary phase including: 9 polar lipids (method 1); 13 combined polar and neutral lipids (method 2); and a combined method that further separates the neutral lipids into 2–4 subclasses based on the presence of fatty acids containing a polar functional group (e.g. hydroxyl) for a total of 20 lipid classes and subclasses separated in a single run (method 3). Polar lipids separated include: the phosphoglycerolipids PG, PE, PI, PS, PC and LPC; the galactoglycerolipids MGDG and DGDG; and a sulfoglycerolipid SQDG. Neutral lipids include TAG, DAG, and MAG classes and sub-classes containing 0–3, 0–2, and 0–1 hydroxy fatty acids, respectively. The hexane/isopropanol/methanol/aqueous system separates polar lipids without the use of chloroform such that it is suitable for radioactivity analysis by in-line flow scintillation counting. Each method was optimized using the natural lipid standards comprised of diverse molecular species that were detected by ELSD. All molecular species of each lipid class eluted together as single peak detected by ELSD. The methods were demonstrated to be suitable for resolving lipid extracts from animal, microbial, and plant sources as well as application to 14C based metabolic tracing of lipid metabolism in leaves and seeds.Kovalchuk, N., Hadjistassou, C., 2020. Fathoming the mechanics of shale gas production at the microscale. Journal of Natural Gas Science and Engineering 78, 103283. by advanced technologies, such as hydraulic fracturing and horizontal drilling, gas shale reservoirs constitute one of the most promising hydrocarbon resources around the world. A combination of ultra-small complex pore throat geometries and an incomplete knowledge of the pertinent physics are partly behind underperforming wells. Further progress in terms of gas recovery hinges on a thorough understanding of the gas behaviour in the pores and between them (i.e., permeability). In this work, we propose a geometrically accurate model from a shale formation inspired from Scanning Electron Microscopy (SEM) imaging. The computational model implements the equations of flow, Klinkenberg permeability and gas compressibility. To compare the model results with experimental measurements, a non-dimensionalisation approach was developed which considers the real gas behaviour and shale permeability characteristics. Non-dimensional gas velocity and flow-rate findings demonstrated an intricate but more realistic flowrate-pressure relationship compared to conventional reservoirs. Owing to its versatility, the non-dimensionalisation methodology can be adapted and generalised to other complex geologies such as carbonate formations. Meanwhile, a flowrate sensitivity analysis was conducted in the context of the matrix and the fluid properties. The sensitivity analysis revealed that, although permeability is the most prominent parameter governing flowrate, reservoir pressure requires even more attention, since it changes considerably during gas production and it can be managed by a suitable development strategy.Kruve, A., 2020. Strategies for drawing quantitative conclusions from nontargeted liquid chromatography–high-resolution mass spectrometry analysis. Analytical Chemistry 92, 4691-4699. Feature aims at giving an overview of different possibilities for quantitatively comparing the results obtained from LC?HRMS-based nontargeted analysis. More specifically, quantification via structurally similar internal standards, different isotope labeling strategies, radiolabeling, and predicted ionization efficiencies are reviewed.About 10 years ago, most of the liquid chromatography (LC) electrospray (ESI) mass spectrometry (MS) analysis of environmental, metabolomics, and pharmaceutical samples were predominantly carried out as targeted analysis. Targeted analyses allow detection and quantification a few selected analytes with the aid of standard substances. Today, the center of gravity is shifting toward nontargeted methods which utilize high-resolution mass spectrometry (HRMS). Furthermore, the targeted and nontargeted methods are merging into each other. LC–HRMS-based nontargeted methods allow detecting compounds recovered from the sample preparation and ionizing in the electrospray ionization (ESI) source. New possibilities arising from applying the machine learning tools to LC–HRMS data have already transformed the process of identifying the compounds. The computer-aided identification process is not compatible with a traditional calibration graph-based quantification methods. The main obstacle arises from the fact that in ESI, different compounds ionize to a very different extent. Differences up to 100 million times have been reported. This phenomenon results in a vastly different response of different compounds at the same concentration and complicates the quantification for compounds without standard substances. However, decision making is hindered without quantitative information. Therefore, the need to obtain quantitative information from the nontargeted analysis is triggering an emerging field of research.Kuloyo, O., Ruff, S.E., Cahill, A., Connors, L., Zorz, J.K., Hrabe de Angelis, I., Nightingale, M., Mayer, B., Strous, M., 2020. Methane oxidation and methylotroph population dynamics in groundwater mesocosms. Environmental Microbiology 22, 1222-1237. of natural gas from unconventional hydrocarbon reservoirs by hydraulic fracturing raises concerns about methane migration into groundwater. Microbial methane oxidation can be a significant methane sink. Here, we inoculated replicated, sand‐packed, continuous mesocosms with groundwater from a field methane release experiment. The mesocosms experienced thirty‐five weeks of dynamic methane, oxygen and nitrate concentrations. We determined concentrations and stable isotope signatures of methane, carbon dioxide and nitrate and monitored microbial community composition of suspended and attached biomass. Methane oxidation was strictly dependent on oxygen availability and led to enrichment of 13C in residual methane. Nitrate did not enhance methane oxidation under oxygen limitation. Methylotrophs persisted for weeks in the absence of methane, making them a powerful marker for active as well as past methane leaks. Thirty‐nine distinct populations of methylotrophic bacteria were observed. Methylotrophs mainly occurred attached to sediment particles. Abundances of methanotrophs and other methylotrophs were roughly similar across all samples, pointing at transfer of metabolites from the former to the latter. Two populations of Gracilibacteria (Candidate Phyla Radiation) displayed successive blooms, potentially triggered by a period of methane famine. This study will guide interpretation of future field studies and provides increased understanding of methylotroph ecophysiology.Kurian, S., Kessarkar, P.M., Purnachandra Rao, V., Reshma, K., Sarkar, A., Pattan, J.N., Naqvi, S.W.A., 2020. Controls on organic matter distribution in oxygen minimum zone sediments from the continental slope off western India. Journal of Marine Systems 207, 103118. causes of organic-rich sediments in contact with the perennial oxygen minimum zone (OMZ) on the continental slope off western India have been debated extensively, largely in relation to two main controlling factors: high productivity in the water column and enhanced preservation due to oxygen deficiency in bottom waters. In order to better understand the causes for organic-richness in sediments, three sediment cores recovered from the upper OMZ (UOMZ) at 500?m, middle OMZ (MOMZ) at 812?m and lower OMZ (LOMZ) at 1168?m water depths from the continental slope off Ratnagiri (west coast of India) were investigated for their organic matter (OM) and their stable isotopic (δ13C and δ15N), geochemical and rock magnetic parameters. The bottom water dissolved oxygen (DO) concentrations were 0.4?μM, 5.8?μM and 25?μM at UOMZ, MOMZ and LOMZ core locations respectively. Maximum age of the sediments recorded in these cores was 4500?yrs?BP. Sedimentation rates in the upper sections of the UOMZ and MOMZ cores were lower (5 to 7?cm/kyr) than that in the LOMZ core (20?cm/kyr). Organic carbon (Corg) content was highest (upto 7.9%) in the UOMZ core than in other cores (upto 4.9%). Enriched δ13Corg values (?18.6 to ?16.8‰) in the MOMZ core were indicative of reworked organic matter in the lower section. The δ15N values ranged from 4 to 7.4‰, however, with lower values for the reworked sediments at MOMZ site. The parameters representing productivity and redox conditions increased towards core top in all the cores, whereas terrigenous parameters decreased towards core top in the MOMZ and LOMZ cores. Despite the MOMZ core was always in OMZ in the lower section, very low Corg content coinciding with high terrigenous and reworked OM were deposited in the sediments prior to 1700?years BP. Rock magnetic properties indicate that the degree of diagenetic conditions varied in different sections of the cores and also among the cores within OMZ. Authigenic magnetite and authigenic uranium occurred in the lower sections of UOMZ and LOMZ cores and, authigenic magnetite in the upper sections of MOMZ core. These results suggest that productivity played an important role in organic-richness of the sediments and bottom water oxygen concentration has little effect on the preservation of OM. Besides, sedimentation rates, reworked organic matter, and topography at the core site indeed contribute on the distribution of organic matter in the Late Holocene sediments.Kutschera, W., 2020. On the enigma of dating the Minoan eruption of Santorini. Proceedings of the National Academy of Sciences 117, 8677-8679. Greek island of Santorini (named Thera in ancient times) is located in the Aegean Sea and experienced a massive volcanic eruption some 3,600 y ago (～1600 BCE). Recent geological investigations have concluded that the eruption was even more massive than originally thought (1). This eruption is commonly referred to as the “Minoan” eruption because it happened when the Minoan civilization on the neighboring island Crete was a thriving force in the Aegean and was probably affected by the eruption. The date of the eruption has been debated for many years (2), because it provides an absolute time marker for the Bronze Age in the Eastern Mediterranean. However, no consensus has been reached for this date based on archaeological methods on the one hand and on various scientific approaches on the other hand (e.g., 14C dating, tree-ring studies, and ice core and stalagmite analysis). For quite some time, a difference of about 100 y persisted between the two methods, sometimes called the “high chronology” for an earlier date in the 17th century BCE favored by the scientific methods and a “low chronology” in the 16th century BCE favored by the archaeological methods. This discrepancy has been discussed on many occasions (3?–5).The importance of an exact date for the history of the Eastern Mediterranean has been metaphorically pointed out by Peter M. Warren from the Department of Archaeology and Anthropology of the University of Bristol (ref. 6, p. 305): “Let us imagine that historians at some future date were investigating the political relationship between Germany and the United Kingdom when the forceful Margaret Thatcher was the latter’s Prime Minister. Some uncertainty had arisen. Most of the investigators understood Thatcher’s relationship was with the equally forceful Chancellor Helmut Kohl, but a smaller school of opinion … Labidi, J., Barry, P.H., Bekaert, D.V., Broadley, M.W., Marty, B., Giunta, T., Warr, O., Sherwood Lollar, B., Fischer, T.P., Avice, G., Caracausi, A., Ballentine, C.J., Halldórsson, S.A., Stefánsson, A., Kurz, M.D., Kohl, I.E., Young, E.D., 2020. Hydrothermal 15N15N abundances constrain the origins of mantle nitrogen. Nature 580, 367-371. is the main constituent of the Earth’s atmosphere, but its provenance in the Earth’s mantle remains uncertain. The relative contribution of primordial nitrogen inherited during the Earth’s accretion versus that subducted from the Earth’s surface is unclear. Here we show that the mantle may have retained remnants of such primordial nitrogen. We use the rare 15N15N isotopologue of N2 as a new tracer of air contamination in volcanic gas effusions. By constraining air contamination in gases from Iceland, Eifel (Germany) and Yellowstone (USA), we derive estimates of mantle δ15N (the fractional difference in 15N/14N from air), N2/36Ar and N2/3He. Our results show that negative δ15N values observed in gases, previously regarded as indicating a mantle origin for nitrogen, in fact represent dominantly air-derived N2 that experienced 15N/14N fractionation in hydrothermal systems. Using two-component mixing models to correct for this effect, the 15N15N data allow extrapolations that characterize mantle endmember δ15N, N2/36Ar and N2/3He values. We show that the Eifel region has slightly increased δ15N and N2/36Ar values relative to estimates for the convective mantle provided by mid-ocean-ridge basalts, consistent with subducted nitrogen being added to the mantle source. In contrast, we find that whereas the Yellowstone plume has δ15N values substantially greater than that of the convective mantle, resembling surface components, its N2/36Ar and N2/3He ratios are indistinguishable from those of the convective mantle. This observation raises the possibility that the plume hosts a primordial component. We provide a test of the subduction hypothesis with a two-box model, describing the evolution of mantle and surface nitrogen through geological time. We show that the effect of subduction on the deep nitrogen cycle may be less important than has been suggested by previous investigations. We propose instead that high mid-ocean-ridge basalt and plume δ15N values may both be dominantly primordial features.Leaf, M.C., Gay, J.S.A., Newbould, M.J., Hewitt, O.R., Rogers, Steven?L., 2020. Calcareous algae and cyanobacteria. Geology Today 36, 75-80. is an informal term used to describe a broad group of simple organisms from the plant kingdom. The organisms included within this grouping are aquatic photosynthetic biota with an extensive range of life habits and forms. These organisms range from micron-sized unicellular forms to giant seaweeds and kelps, which can grow to several metres long. Both benthic and planktonic modes of life are known and display a wide variety of life cycles.Lee, C.P., Riva, M., Wang, D., Tomaz, S., Li, D., Perrier, S., Slowik, J.G., Bourgain, F., Schmale, J., Prevot, A.S.H., Baltensperger, U., George, C., El Haddad, I., 2020. Online aerosol chemical characterization by extractive electrospray ionization–ultrahigh-resolution mass spectrometry (EESI-Orbitrap). Environmental Science & Technology 54, 3871-3880. mass spectrometry techniques for the online measurement of organic aerosol (OA) composition are subjected to either thermal/ionization-induced artifacts or limited mass resolving power, hindering accurate molecular characterization. Here, we combined the soft ionization capability of extractive electrospray ionization (EESI) and the ultrahigh mass resolution of Orbitrap for real-time, near-molecular characterization of OAs. Detection limits as low as tens of ng m–3 with linearity up to hundreds of μg m–3 at 0.2 Hz time resolution were observed for single- and mixed-component calibrations. The performance of the EESI-Orbitrap system was further evaluated with laboratory-generated secondary OAs (SOAs) and filter extracts of ambient particulate matter. The high mass accuracy and resolution (140?000 at m/z 200) of the EESI-Orbitrap system enable unambiguous identification of the aerosol components’ molecular composition and allow a clear separation between adjacent peaks, which would be significantly overlapping if a medium-resolution (20?000) mass analyzer was used. Furthermore, the tandem mass spectrometry (MS2) capability provides valuable insights into the compound structure. For instance, the MS2 analysis of ambient OA samples and lab-generated biogenic SOAs points to specific SOA precursors in ambient air among a range of possible isomers based on fingerprint fragment ions. Overall, this newly developed and characterized EESI-Orbitrap system will advance our understanding of the formation and evolution of atmospheric aerosols.Lee, J., Chung, E., 2020. Lithium recovery by solvent extraction from simulated shale gas produced water – Impact of organic compounds. Applied Geochemistry 116, 104571. gas produced water has a large number of inorganic compounds, originating from the shale layer and the fracturing fluid. Especially, the Marcellus shale gas produced water contains a relatively high concentration of lithium, one of the important metals in various industries; as a result, there have been several studies on recovering lithium from the produced water. However, the fluid also includes organic compounds, but their probable inhibitory effect on the recovery of profitable metal has not been thoroughly examined. In this study, solvent extraction was implemented to recover lithium from the produced water, containing different types and concentrations of alkanes in two consecutive stages. The first and second stage involved the removal of the divalent ions in the produced water, as well as the extraction of Li+ ions, respectively. During the extraction process, there was an inhibitory influence of organic compounds, with their effects on the Li recovery efficiency predominantly observed in the first stage vs. the second stage. Final lithium recovery efficiency after two extraction stages decreased with increasing alkane chain length and increasing concentrations of n-hexane.Lee, M., Jung, J.-Y., Park, K.-C., Choi, S.-H., 2020. Environmental and economic loss analyses of the oil discharge from shipwreck for salvage planning. Marine Pollution Bulletin 155, 111142. this study, we carry out environmental and economic loss analyses of the oil discharge from the shipwreck Jeh Hun. By performing 500 simulations of hypothetical oil spill cases, we obtain the minimum and worst damage cases. In the minimum damage case, there is just marine pollution without coastal pollution or aquaculture farm pollution. On the other hand, in the worst damage case, there is serious marine pollution, coastal pollution, and aquaculture pollution. The main purpose of the environmental and economic loss analyses is to support salvage planning for the shipwreck, because we have to consider the oil discharge from the shipwreck during oil removal and salvage. The results of this study show that the best salvage time is early morning in winter, when the northwest wind and maximum flood tide are dominant resulting in the spilt oil going forward into the open sea without coastal pollution and aquaculture pollution.Lekang, K., Lanzén, A., Jonassen, I., Thompson, E., Troedsson, C., 2020. Evaluation of a eukaryote phylogenetic microarray for environmental monitoring of marine sediments. Marine Pollution Bulletin 154, 111102. exploitation of resources in sensitive marine ecosystems emphasizes the importance of knowledge regarding ecological impacts. However, current bio-monitoring practices are limited in terms of target-organisms and temporal resolution. Hence, developing new technologies is vital for enhanced ecosystem understanding. In this study, we have applied a prototype version of a phylogenetic microarray to assess the eukaryote community structures of marine sediments from an area with ongoing oil and gas drilling activity. The results were compared with data from both sequencing (metabarcoding) and morphology-based monitoring to evaluate whether microarrays were capable of detecting ecosystem disturbances. A significant correlation between microarray data and chemical pollution indicators, as well as sequencing-based results, was demonstrated, and several potential indicator organisms for pollution-associated parameters were identified, among them a large fraction of microorganisms not covered by traditional morphology-based monitoring. This suggests that microarrays have a potential in future environmental monitoring.Lemaire, O.N., Jespersen, M., Wagner, T., 2020. CO2-fixation strategies in energy extremophiles: What can we learn from acetogens? Frontiers in Microbiology 11, 486. doi: 10.3389/fmicb.2020.00486. of CO2-fixation became a worldwide priority enhanced by the will to convert this greenhouse gas into fuels and valuable chemicals. Because of its high stability, CO2-activation/fixation represents a true challenge for chemists. Autotrophic microbial communities, however, perform these reactions under standard temperature and pressure. Recent discoveries shine light on autotrophic acetogenic bacteria and hydrogenotrophic methanogens, as these anaerobes use a particularly efficient CO2-capture system to fulfill their carbon and energy needs. While other autotrophs assimilate CO2 via carboxylation followed by a reduction, acetogens and methanogens do the opposite. They first generate formate and CO by CO2-reduction, which are subsequently fixed to funnel the carbon toward their central metabolism. Yet their CO2-reduction pathways, with acetate or methane as end-products, constrain them to thrive at the “thermodynamic limits of Life”. Despite this energy restriction acetogens and methanogens are growing at unexpected fast rates. To overcome the thermodynamic barrier of CO2-reduction they apply different ingenious chemical tricks such as the use of flavin-based electron-bifurcation or coupled reactions. This mini-review summarizes the current knowledge gathered on the CO2-fixation strategies among acetogens. While extensive biochemical characterization of the acetogenic formate-generating machineries has been done, there is no structural data available. Based on their shared mechanistic similarities, we apply the structural information obtained from hydrogenotrophic methanogens to highlight common features, as well as the specific differences of their CO2-fixation systems. We discuss the consequences of their CO2-reduction strategies on the evolution of Life, their wide distribution and their impact in biotechnological applications.Leung, P.M., Bay, S.K., Meier, D.V., Chiri, E., Cowan, D.A., Gillor, O., Woebken, D., Greening, C., 2020. Energetic basis of microbial growth and persistence in desert ecosystems. mSystems 5, e00495-19. life is surprisingly abundant and diverse in global desert ecosystems. In these environments, microorganisms endure a multitude of physicochemical stresses, including low water potential, carbon and nitrogen starvation, and extreme temperatures. In this review, we summarize our current understanding of the energetic mechanisms and trophic dynamics that underpin microbial function in desert ecosystems. Accumulating evidence suggests that dormancy is a common strategy that facilitates microbial survival in response to water and carbon limitation. Whereas photoautotrophs are restricted to specific niches in extreme deserts, metabolically versatile heterotrophs persist even in the hyper-arid topsoils of the Atacama Desert and Antarctica. At least three distinct strategies appear to allow such microorganisms to conserve energy in these oligotrophic environments: degradation of organic energy reserves, rhodopsin- and bacteriochlorophyll-dependent light harvesting, and oxidation of the atmospheric trace gases hydrogen and carbon monoxide. In turn, these principles are relevant for understanding the composition, functionality, and resilience of desert ecosystems, as well as predicting responses to the growing problem of desertification.This minireview went through the journal&#039;s normal peer review process. DayTwo sponsored the minireview and its associated video but had no editorial input on the content.Lewis, J.P., Tarnecki, J.H., Garner, S.B., Chagaris, D.D., Patterson, W.F., 2020. Changes in reef fish community structure following the Deepwater Horizon oil spill. Scientific Reports 10, 5621. anthropogenic disturbances can have direct and indirect effects on marine communities, with direct effects often taking the form of widespread injury or mortality and indirect effects manifesting as changes in food web structure. Here, we report a time series that captures both direct and indirect effects of the Deepwater Horizon Oil Spill (DWH) on northern Gulf of Mexico (nGoM) reef fish communities. We observed significant changes in community structure immediately following the DWH, with a 38% decline in species richness and 26% decline in Shannon-Weiner diversity. Initial shifts were driven by widespread declines across a range of trophic guilds, with subsequent recovery unevenly distributed among guilds and taxa. For example, densities of small demersal invertivores, small demersal browsers, generalist carnivores, and piscivores remained persistently low with little indication of recovery seven years after the DWH. Initial declines among these guilds occurred prior to the arrival of the now-widespread, invasive lionfish (Pterois spp.), but their lack of recovery suggests lionfish predation may be affecting recovery. Factors affecting persistently low densities of generalist carnivores and piscivores are not well understood but warrant further study given the myriad ecosystem services provided by nGoM reef fishes.Li, A., 2020. Spitzer’s perspective of polycyclic aromatic hydrocarbons in galaxies. Nature Astronomy 4, 339-351. aromatic hydrocarbon (PAH) molecules are abundant and widespread throughout the Universe, as revealed by their distinctive set of emission bands at 3.3, 6.2, 7.7, 8.6, 11.3 and 12.7 μm, which are characteristic of their vibrational modes. They are ubiquitously seen in a wide variety of astrophysical regions, ranging from planet-forming disks around young stars to the interstellar medium of the Milky Way and other galaxies out to high redshifts at z ? 4. PAHs profoundly influence the thermal budget and chemistry of the interstellar medium by dominating the photoelectric heating of the gas and controlling the ionization balance. Here I review the current state of knowledge of the astrophysics of PAHs, focusing on their observational characteristics obtained from the Spitzer Space Telescope and their diagnostic power for probing the local physical and chemical conditions and processes. Special attention is paid to the spectral properties of PAHs and their variations revealed by the Infrared Spectrograph onboard Spitzer across a much broader range of extragalactic environments (for example, distant galaxies, early-type galaxies, galactic halos, active galactic nuclei and low-metallicity galaxies) than was previously possible with the Infrared Space Observatory or any other telescope facilities. Also highlighted is the relation between the PAH abundance and the galaxy metallicity established for the first time by Spitzer.Li, D., Liu, B., Zheng, H., Xiao, X., Li, Z., Luan, E., Li, W., Yang, Y., Wang, Y., Long, Q., Song, J., Zhang, G., 2020. XY-Meta: A high-efficiency search engine for large-scale metabolome annotation with accurate FDR estimation. Analytical Chemistry 92, 5701-5707. control has been a huge challenge for large-scale metabolome annotation. Although recent research indicated that the target–decoy strategy could be implemented to estimate FDR, it is hard to perform FDR control due to the difficulty of getting a reliable decoy database because of the complex fragmentation mechanism of metabolites and ubiquitous isomers. To tackle this problem, we developed a decoy generation method, which generates forged spectra from the reference target database by preserving the original reference signals to simulate the presence of isomers of metabolites. Benchmarks on GNPS data sets in Passatutto showed that the decoy database generated by our method is closer to the actual FDR than other methods, especially in the low FDR range (0–0.05). Large-scale metabolite annotation on 35 data sets showed that strict FDR reduced the number of annotated metabolites but increased the spectral efficiency, indicating the necessity of quality control. We recommended that the FDR threshold should be set to 0.01 in large-scale metabolite annotation. We implemented decoy generation, database search, and FDR control into a search engine called XY-Meta. It facilitates large-scale metabolome annotation applications.Li, J., Gu, L., Bai, S., Wang, J., Su, L., Wei, B., Zhang, L., Fang, J., 2020. Characterization of particle-associated and free-living bacterial and archaeal communities along the water columns of the South China Sea. Biogeosciences Discussions 2020, 1-35. is a growing recognition of the role of particle-attached (PA) and free-living (FL) microorganisms in marine carbon cycle. However, current understanding of PA and FL microbial communities is largely on those in the upper photic zone, and relatively fewer studies have focused on microbial communities of the deep ocean. Moreover, archaeal populations receive even less attention. In this study, we determined bacterial and archaeal community structures of both the PA and FL assemblages at different depths, from the surface to the bathypelagic zone along two water column profiles in the South China Sea. Our results suggest that environmental parameters including depth, seawater age, salinity, POC, DOC, DO and silicate play a role in structuring these microbial communities. Generally, the PA microbial communities have relatively low abundance and diversity compared with the FL microbial communities at most depths. Further microbial community analysis revealed that PA and FL fractions generally accommodate significantly divergent microbial compositions at each depth. The PA bacterial communities mainly comprise members of Actinobacteria and γ-Proteobacteria, together with some from Bacteroidetes, Planctomycetes and δ-Proteobacteria, while the FL bacterial lineages are mostly distributed within α-, γ-Proteobacteria, Actinobacteria and Bacteroidetes, along with certain members from β-, δ-Proteobacteria, Planctomycetes and Firmicutes. Moreover, there is an obvious shifting in the dominant PA and FL bacterial compositions along the depth profiles from the surface to the bathypelagic deep. By contrast, both PA and FL archaeal communities dominantly consist of Marine Group II (MGII) and Marine Group I (MGI), together with variable minor Marine Group III (MGIII), Methanosarcinales, Marine Benthic Group A (MBG-A) and Woesearchaeota. However, the pronounced distinction of archaeal community compositions between PA and FL fractions are observed at finer taxonomic level. A high proportion overlap of microbial compositions between PA and FL fractions implies that most microorganisms are potentially generalists with PA and FL dual lifestyle for versatile metabolic flexibility. In addition, microbial distribution along the depth profile indicates a potential vertical connectivity between the surface-specific microbial lineages and those in the deep ocean, likely through microbial attachment to sinking particles.Li, J., Gu, X., Gui, Y., 2020. Prokaryotic diversity and composition of sediments from Prydz Bay, the Antarctic Peninsula region, and the Ross Sea, Southern Ocean. Frontiers in Microbiology 11, 783. doi: 10.3389/fmicb.2020.00783. V3–V4 hypervariable regions of the 16S ribosomal RNA gene were analyzed to assess prokaryotic diversity and community compositions within 19 surface sediment samples collected from three different regions (depth: 250–3,548 m) of Prydz Bay, the Antarctic Peninsula region, and the Ross Sea. In our results, we characterized 1,079,709 clean tag sequences representing 43,227 operational taxonomic units (OTUs, 97% similarity). The prokaryotic community distribution exhibited obvious geographical differences, and the sequences formed three distinct clusters according to the samples’ origins. In general, the biodiversity of Prydz Bay was higher than those of the Antarctic Peninsula region and the Ross Sea, and there were similar prokaryotic communities in different geographic locations. The most dominant clades in the prokaryotic communities were Proteobacteria, Bacteroidetes, Thaumarchaeota, Oxyphotobacteria, Deinococcus-Thermus, Firmicutes, Acidobacteria, Fusobacteria, and Planctomycetes, but unique prokaryotic community compositions were found in each of the sampling regions. Our results also demonstrated that the prokaryotic diversity and community distribution were mainly influenced by geographical and physicochemical factors, such as Zn, V, Na, K, water depth, and especially geographical distance (longitude variation of sample location) and Ba ion content. Moreover, geochemical factors such as nutrient contents (TC, P, and Ca) also played important roles in prokaryotic diversity and community distribution. This represents the first report that Ba ion content has an obvious effect on prokaryotic diversity and community distribution in Southern Ocean sediments.Li, M., Zhu, R., Song, X., Wang, Z., Weng, H., Liang, J., 2020. A sensitive method for the quantification of short-chain fatty acids by benzyl chloroformate derivatization combined with GC-MS. Analyst 145, 2692-2700. fatty acids (SCFAs) were identified as critical markers in the diagnosis of chronic and metabolic diseases, but a sensitive and stable method to determine SCFAs in feces is a challenge for analysts due to the high volatility. Herein, a sensitive and accurate method to determine SCFAs adopting precolumn derivatization coupled with gas chromatography-mass spectrometry (GC-MS) has been developed. Benzyl chloroformate (BCF) was chosen as the reaction reagent and emulsified derivatization was applied to homogenize the reaction system. Higher sensitivity, wider application and satisfactory derivatization efficiency were obtained using the developed method. An excellent method validation showed a good linearity ranging from 0.9947 to 0.9998. At the same time, the intra-day and inter-day precision were achieved in the range of 0.56% to 13.07%. The lower limits of detection of all target analytes varied from 0.1 to 5 pg. The recovery ranged from 80.87% to 119.03%, and storage stability under three different conditions was also determined. This method was also successfully applied to the analysis of SCFAs in mice fecal samples to illustrate the significant differences between normal and type 2 diabetes mellitus mice.Li, S., Hu, Y., Liu, W., Chen, Y., Wang, F., Lu, X., Zheng, W., 2020. Untargeted volatile metabolomics using comprehensive two-dimensional gas chromatography-mass spectrometry – A solution for orange juice authentication. Talanta 217, 121038. juice is one of the most consumed fruit juices worldwide and its adulteration has been a long-lasting concern. In this study, an untargeted volatile metabolomics using a comprehensive two-dimensional gas chromatography-quadrupole mass spectrometry (GC?×?GC-qMS) was developed to systematically authenticate orange juice. At least 405 citrus whole fruits were collected, belongs to 58 types of orange samples and 23 types of non-orange citrus. The fruit juices were prepared in the laboratory and analyzed using the comprehensive GC?×?GC-qMS instrument. After optimizing the instrumental settings, this novel method was able to identified ~250 volatiles in each juice sample, covering a variety types of hydrocarbons, esters, alcohols, aldehydes, ketones and others. Combining with unsupervised principal component analysis and supervised partial least squares-discriminant analysis , this novel analytical tool was able to authenticate orange juice from a broad perspectives with a high accuracy in the cross-validation model: 1) differentiating orange juice from non-orange citrus juice (99% accuracy), 2) recognizing orange harvesting years (100% accuracy) and geographical origins (96% accuracy), and 3) distinguishing original pure orange juice from the reconstituted juice (94% accuracy). Key volatile metabolites associated with different categories of samples were also identified after thorough investigation of the loading values of the classification models. These metabolites have high potential to be used as food-markers to design targeted analytical methods for orange juice authentication. This novel comprehensive GC?×?GC-qMS-based method is ideal for governmental laboratories and the food industry to routinely authenticate orange juice.Li, W., Lu, S., Li, J., Zhang, P., Wang, S., Feng, W., Wei, Y., 2020. Carbon isotope fractionation during shale gas transport: Mechanism, characterization and significance. Science China Earth Sciences 63, 674-689. gas in-place (GIP) content and the ratio of adsorbed/free gas are two key parameters for the assessment of shale gas resources and have thus received extensive attention. A variety of methods have been proposed to solve these issues, however none have gained widespread acceptance. Carbon isotope fractionation during the methane transport process provides abundant information, serving as an effective method for differentiating the gas transport processes of adsorbed gas and free gas and ultimately evaluating the two key parameters. In this study, four stages of methane carbon isotope fractionation were documented during a laboratory experiment that simulated gas transport through shale. The four stages reflect different transport processes: the free gas seepage stage (I), transition stage (II), adsorbed gas desorption stage (III) and concentration diffusion stage (IV). Combined with the results of decoupling experiments, the isotope fractionation characteristics donated by the single effect (seepage, adsorption-desorption and diffusion) were clearly revealed. We further propose a technique integrating the Amoco curve fit (ACF) method and carbon isotope fractionation (CIF) to determine the dynamic change in adsorbed and free gas ratios during gas production. We find that the gases produced in stage I are primarily composed of free gas and that carbon isotope ratios of methane (δ13C1) are stable and equal to the ratios of source gas (δ13C01). In stage II, the contribution of free gas decreases, while the proportion of adsorbed gas increases, and the δ13C1 gradually becomes lighter. With the depletion of free gas, the adsorbed gas contribution in stage III reaches 100%, and the δ13C1 becomes heavier. Finally, in stage IV, the desorbed gas remaining in the pore spaces diffuses out under the concentration difference, and the δ13C1 becomes lighter again and finally stabilizes. In addition, a kinetic model for the quantitative description of isotope fractionation during desorption and diffusion was established.Li, W., Wu, J., Huang, X., 2020. Facile fabrication of functional groups-rich sorbent for the efficient enrichment of aromatic N- and S-containing compounds in environmental waters. Analytica Chimica Acta 1113, 36-42. strategy is designed for the pretreatment of low contents of aromatic N- and S-containing compounds (ANSCs) in environmental waters prior to chromatographic analysis. To enrich studied ANSCs effectively, poly (9-vinylanthracene/4-vinylphenylboronic acid-co-ethylene dimethacrylate/divinylbenzene) polymeric monolithic sorbent were facilely fabricated using the one-step free radical polymerization. Various technologies were employed to investigate the structure and morphology of the resultant monolith. Combining with solid-phase microextraction format, the sorbent exhibited satisfying concentrated performance for ANSCs through multiply interactions under the optimized conditions. After desorption with eluent, the retained analytes were analyzed by HPLC. Results showed that the extraction efficiencies ranged from 51.6 to 93.2%. The linear ranges and limits of detection were 0.01–150?μg/L and 0.63–2.64?ng/L, respectively. Furthermore, the precisions were all below 10%. The introduced approach was productively practiced on three real water samples for simultaneous quantification of studied ANSCs, and the fortified recoveries ranged from 81.5 to 118%. All the results well evidenced that prepared sorbent can enrich ANSCs effectively and the introduced method is reliable alternative for routine analysis of ANSCs in environmental waters.Li, W., Zhu, Y., Li, S., Lu, Y., Wang, J., Zhu, K., Chen, J., Zheng, Y., Zheng, Z., 2020. Catalytic fast pyrolysis of cellulose over Ce0.8Zr0.2-xAlxO2 catalysts to produce aromatic hydrocarbons: Analytical Py-GC?×?GC/MS. Fuel Processing Technology 205, 106438. pyrolysis-comprehensive two-dimensional gas chromatography/mass spectrometry (Py-GC × GC/MS) was employed for the on-line analysis of cellulose via catalytic pyrolysis with different catalysts and catalytic temperatures to study the products and aromatic hydrocarbons selectivity. The catalysts were subjected to characterization methods, including XRD, TEM, NH3-TPD, to investigate the effects of the physicochemical properties of the catalyst on the product distribution. Results showed that the Ce0.8Zr0.2-xAlxO2 could significantly promote the formation of aromatic hydrocarbons under 400–550 °C. A lower catalytic temperature (≤350 °C) favored the formation of furan compounds, and a higher catalytic temperature (≥450 °C) supported the formation of aromatic hydrocarbons. The relative peak area of the aromatics prepared by using the Ce0.8Zr0.15Al0.05O2 catalyst was the highest being 85.24% at 550 °C. Moreover, the selectivity of the single-ring aromatics, such as benzene, toluene and xylene, were significantly affected by the presence of the Ce0.8Zr0.2-xAlxO2 catalysts. The higher total acidity of Ce0.8Zr0.15Al0.05O2 favored the formation of benzene and toluene. Additionally, the Ce0.8Zr0.15Al0.05O2 catalyst had a great thermal stability. The catalyst recycling tests showed that the Ce0.8Zr0.15Al0.05O2 catalyst can be reused five times to produce aromatic-rich bio-oil via catalytic fast pyrolysis.Li, X.-Y., Li, X.-S., Wang, Y., Zhang, Y., 2020. Optimization of the production pressure for hydrate dissociation by depressurization. Energy & Fuels 34, 4296-4306. gas hydrate is considered as a promising energy resource in the future. How to choose a suitable production pressure is a key issue when depressurization is taken as the production way of gas hydrate. In this study, we conducted the experiments of methane hydrate dissociation under different production pressures. The influences of production pressure on the hydrate dissociation rate and the method to optimize the production pressure were studied. The experimental results illustrated that two stages were contained in the hydrate dissociation by depressurization: the depressurization stage (DS) and the constant pressure stage (CPS). In the DS, the sensible heat of the sediments was used for hydrate dissociation, and the hydrate dissociation amount increased with the decrease of the production pressure. In the CPS, the required heat for hydrate dissociation was transferred from the surroundings. As the production pressure decreased, the hydrate dissociation rate increased. Although the lower production pressure can improve the hydrate dissociation rate, the energy input of hydrate production in field for depressurization with the lower production pressure could be larger than that with the higher production pressure. In order to improve the production efficiency, an optimizing method of production pressure was first proposed. Based on the experimental data, the optimum production pressure was calculated with this method. The calculation result indicates that the production pressure should be as close to the pressure of hydrate quadruple point (2.56 MPa) as possible. Moreover, it is worth noting that the optimum production pressure in field production could be different from that obtained by experiments because the optimum production pressure is determined by the actual function of the energy input in field. However, the evaluation method is universal.Li, Y., Chen, M., Song, H., Yuan, P., Zhang, B., Liu, D., Zhou, H., Bu, H., 2020. Effect of cations (Na+, K+, and Ca2+) on methane hydrate formation on the external surface of montmorillonite: Insights from molecular dynamics simulation. ACS Earth and Space Chemistry 4, 572-582. this study, molecular dynamics simulations were performed to investigate the effects of montmorillonite with different surface cations (i.e., Na+, K+, and Ca2+) on CH4 hydrate formation. The results showed that CH4 hydrate cages are mainly formed beyond the montmorillonite surface. The inner-sphere adsorption of K+ and the outer-sphere adsorption of Na+ and Ca2+ occurred on the montmorillonite surface, leading to differences in order parameters and hydrogen bond number of H2O molecules. The number of structure I cages increased faster than that of structure II cages in different models and were in agreement with the fact that CH4 molecules can only form sI hydrate crystals. The number of 512 cages increased in the order: Na–Mt < Ca–Mt < K–Mt. The aqueous environment dominated by K+ on the external surface of montmorillonite facilitate heterogeneous nucleation of CH4 hydrate rather than that by Ca2+ or Na+. The abovementioned findings suggest that the coordination structure of cations on the external surface of montmorillonite plays an important role in CH4 hydrate formation through altering the occupation of CH4 hydrate.Liao, Y., Liu, W., Pan, Y., Wang, X., Wang, Y., Peng, P.a., 2020. Superimposed secondary alteration of oil reservoirs. Part I: Influence of biodegradation on the gas generation behavior of crude oils. Organic Geochemistry 142, 103965. to multi-stage tectonic movements, many oil reservoirs in typical superimposed basins of China have undergone more than one secondary alteration. Typically, these oil reservoirs experienced biodegradation at an early stage followed by thermal alteration at a later stage. The extent of each secondary alteration can be variable. Here, the succession of biodegradation and subsequent thermal alteration is called superimposed secondary alteration. This study aims not only to show the superimposed secondary alteration process in the reservoir by laboratory simulations, but also to show how varying extents of biodegradation influence the gas generation behavior of crude oils under thermal stress. Hydrocarbon gas generation potential is significantly reduced at the low to moderate biodegradation stage because of the selective removal of normal and branched alkanes. Hydrocarbon gases generated from the more severely biodegraded oils are drier, attributable to the decreasing yields of C2–C5 gases relative to methane. In the oil-generative window, the methane generated from more severely biodegraded oils is relatively enriched in 13C. Kinetic modeling suggests that moderately and severely biodegraded oils are thermally less stable than the non-biodegraded and slightly biodegraded oils. The bulk hydrocarbon gas yields from the non-biodegraded oil do not exceed those from the moderately biodegraded oils until EasyRo > 1.6%. For EasyRo of 1.6–2.5%, pyro-bitumen yields from heavily to severely biodegraded oils were about 2–4 times that of non-biodegraded oil. That is, the gas yields normalized to the weight of pyro-bitumen from heavily to severely biodegraded oil is only 25–50% of the gas yield of non-biodegraded oil. Therefore, hydrocarbon gas resource potential based on pyro-bitumen content must be very carefully considered in cases of superimposed secondary alteration.Lightfoot, E., ?aval, S., Calaon, D., Appleby, J., Santana, J., Cianciosi, A., Fregel, R., Seetah, K., 2020. Colonialism, slavery and ‘The Great Experiment’: Carbon, nitrogen and oxygen isotope analysis of Le Morne and Bois Marchand cemeteries, Mauritius. Journal of Archaeological Science: Reports 31, 102335., colonialism and emancipation are important aspects of archaeological research in the Atlantic region, but the lifeways of colonial populations remain understudied in the Indian Ocean World. Here, we help to redress this imbalance by undertaking stable isotope analysis (C, N and O) on human remains from Mauritius, a location which played an important role in the movement of people across the Indian Ocean and beyond. The results indicate that a wide range of diets was consumed in Mauritius during the nineteenth century, varying with location and circumstances of birth such that while a range of resources would have been available on the island, the proportions of the different resources consumed was different for different people. Most people consumed some C4 resources, likely maize, although the proportion of the diet that this represented varied widely. There is some evidence for the use of marine resources, with one individual consuming a very high proportion of marine foods. In general, the people buried at the post-emancipation cemetery Le Morne consumed a higher proportion of C4 foodstuffs and a lower proportion of animal protein and/or marine resources than those individuals buried at the formal public cemetery Bois Marchand. The data from La Morne are consistent with a population that lived separately as children and then came to live, and eat, together during adulthood. This study has shown a much more nuanced picture of diet in Mauritius at this time than was previously known. The research complements and enriches the historic narrative, adding dimensions to small islands that would otherwise remain obscure in the absence of rigorous scientific assessment of archaeological finds.Lim, J.K., Kim, Y.J., Yang, J.-A., Namirimu, T., Yang, S.-H., Park, M.-J., Kwon, Y.M., Lee, H.S., Kang, S.G., Lee, J.-H., Kwon, K.K., 2020. Thermococcus indicus sp. nov., a Fe(III)-reducing hyperthermophilic archaeon isolated from the Onnuri Vent Field of the Central Indian Ocean ridge. Journal of Microbiology 58, 260-267. strictly anaerobic, dissimilatory Fe(III)-reducing hyperthermophilic archaeon, designated as strain IOH1T, was isolated from a new deep-sea hydrothermal vent (Onnuri Vent Field) area in the Central Indian Ocean ridge. Strain IOH1T showed > 99% 16S rRNA gene sequence similarity with Thermococcus celericrescens TS2T (99.4%) and T. siculi DSM 12349T (99.2%). Additional three species T. barossii SHCK-94T (99.0%), T. celer Vu13T (98.8%), and T. piezophilus (98.6%) showed > 98.6% of 16S rRNA gene sequence similarity, however, the maximum OrthoANI value is 89.8% for the genome of T. celericrescens TS2T. Strain IOH1T cells are coccoid, 1.2–1.8 μm in diameter, and motile by flagella. Growth was at 70–82°C (optimum 80°C), pH 5.4–8.0 (optimum pH 6.0) with 2–4% (optimum 3%) NaCl. Growth of strain IOH1T was enhanced by starch, pyruvate, D(+)-maltose and maltodextrin as a carbon sources, and elemental sulfur as an electron acceptor; clearly different from those of related species T. celecrescens DSM 17994T and T. siculi DSM 12349T. Strain IOH1T, T. celercrescence DSM 17994T, and T. siculi DSM 12349T reduced soluble Fe(III)-citrate present in the medium, whereas the amount of total cellular proteins increased with the concomitant accumulation of Fe(II). We determined a circular chromosome of 2,234 kb with an extra-chromosomal archaeal plasmid, pTI1, of 7.7 kb and predicted 2,425 genes. The DNA G + C content was 54.9 mol%. Based on physiological properties, phylogenetic, and genome analysis, we proposed that strain IOH1T (= KCTC 15844T = JCM 39077T) is assigned to a new species in the genus Thermococcus and named Thermococcus indicus sp. nov.Lin, M., Grandinetti, G., Hartnell, L.M., Bliss, D., Subramaniam, S., Rikihisa, Y., 2020. Host membrane lipids are trafficked to membranes of intravacuolar bacterium Ehrlichia chaffeensis. Proceedings of the National Academy of Sciences 117, 8032-8043.: Biological membranes are essential for life. Although bacteria and eukaryotic cells have evolved to produce membranes of different compositions, several bacterial pathogens can hijack and utilize host-synthesized membrane lipids. Here, we show that an obligatory intracellular pathogen, Ehrlichia chaffeensis, deficient in biosynthesis of cholesterol and some glycerophospholipids, actively acquires host-derived membrane components within membrane-bound inclusions (vacuoles). The trafficking of host membrane components to Ehrlichia and membrane-bound inclusions appears to occur via endocytosis and autophagy induced by a bacteria-secreted protein. Numerous intraluminal vesicles were found in Ehrlichia inclusions that may function as a membrane reserve for rapid proliferation of Ehrlichia. Our findings provide insights into host membrane assimilation by an intracellular pathogen, which can be exploited for antibacterial therapy.Abstract: Ehrlichia chaffeensis, a cholesterol-rich and cholesterol-dependent obligate intracellular bacterium, partially lacks genes for glycerophospholipid biosynthesis. We found here that E. chaffeensis is dependent on host glycerolipid biosynthesis, as an inhibitor of host long-chain acyl CoA synthetases, key enzymes for glycerolipid biosynthesis, significantly reduced bacterial proliferation. E. chaffeensis cannot synthesize phosphatidylcholine or cholesterol but encodes enzymes for phosphatidylethanolamine (PE) biosynthesis; however, exogenous NBD-phosphatidylcholine, Bodipy-PE, and TopFluor-cholesterol were rapidly trafficked to ehrlichiae in infected cells. DiI (3,3′-dioctadecylindocarbocyanine)-prelabeled host-cell membranes were unidirectionally trafficked to Ehrlichia inclusion and bacterial membranes, but DiI-prelabeled Ehrlichia membranes were not trafficked to host-cell membranes. The trafficking of host-cell membranes to Ehrlichia inclusions was dependent on both host endocytic and autophagic pathways, and bacterial protein synthesis, as the respective inhibitors blocked both infection and trafficking of DiI-labeled host membranes to Ehrlichia. In addition, DiI-labeled host-cell membranes were trafficked to autophagosomes induced by the E. chaffeensis type IV secretion system effector Etf-1, which traffic to and fuse with Ehrlichia inclusions. Cryosections of infected cells revealed numerous membranous vesicles inside inclusions, as well as multivesicular bodies docked on the inclusion surface, both of which were immunogold-labeled by a GFP-tagged 2×FYVE protein that binds to phosphatidylinositol 3-phosphate. Focused ion-beam scanning electron microscopy of infected cells validated numerous membranous structures inside bacteria-containing inclusions. Our results support the notion that Ehrlichia inclusions are amphisomes formed through fusion of early endosomes, multivesicular bodies, and early autophagosomes induced by Etf-1, and they provide host-cell glycerophospholipids and cholesterol that are necessary for bacterial proliferation.Lin, Y., Campbell, A.N., Bhattacharyya, A., DiDonato, N., Thompson, A.M., Tfaily, M.M., Nico, P.S., Silver, W.L., Pett-Ridge, J., 2020. Differential effects of redox conditions on the decomposition of litter and soil organic matter. Biogeosciences Discussions 2020, 1-25. redox conditions exert substantial influence on biogeochemical processes in terrestrial ecosystems. Humid tropical forest soils are often characterized by fluctuating redox dynamics, yet how these dynamics affect patterns in soil versus litter decomposition and associated CO2 fluxes is not well understood. We used a 13C-labeled litter addition to explicitly follow the decomposition of litter-derived vs. native soil-derived organic matter in response to four different soil redox regimes – static oxic or anoxic, and two oscillating treatments – in soil from the Luquillo Experimental Forest, Puerto Rico. We coupled this incubation experiment with high-resolution mass spectrometry to characterize the preferential decomposition of specific classes of organic molecules. CO2 production from litter and soil organic matter (SOM) showed distinctly different responses to redox manipulation. The cumulative production of SOM-derived CO2 was positively correlated with the length of soil exposure to an oxic headspace (r?=?0.89, n?=?20), whereas cumulative 13C-litter-derived CO2 production was not linked to oxygen availability. The CO2 production rate from litter was highest under static anoxic conditions in the first half of the incubation period, and later dropped to the lowest among all redox treatments. In the consistently anoxic soils, we observed the depletion of more oxidized water-extractable organic matter (especially amino sugars, carbohydrates, and proteins) over time, suggesting that under anaerobic conditions, microbes preferentially used more oxidized litter-derived compounds during the early stages of decomposition. Results from kinetic modeling showed that more frequent anoxic exposure limited the decomposition of a slow-cycling C pool, but not a fast-cycling pool. Overall, our results demonstrate that substrate source – freshly added litter vs. native organic matter – plays an important role in the redox sensitivity of organic matter decomposition. In soil environments that regularly experience redox fluctuations, anaerobic heterotrophs can be surprisingly effective in degrading fresh plant litter.Lin, Z.-Y., Chen, H.-W., Lin, H.-J., 2020. Trophic model of a deep-sea ecosystem with methane seeps in the South China Sea. Deep Sea Research Part I: Oceanographic Research Papers 159, 103251. megafauna in deep-sea ecosystems with and without methane seeps in the South China Sea were quantified during 2013–2016. In total, more than 190 taxa were identified. Stable isotopic analyses (δ13C, δ15N) on the tissues of these megafauna were used to provide complementary data to reveal their trophic relationships. Ecopath models were constructed to show the flow of matter within deep-sea ecosystems. There were four integer trophic levels in both deep-sea models. Most of the omnivory indices of the megafauna in the models were small, indicating the specialized diet niches of the megafauna. The mixed trophic impact results showed that both models were top-down controlled. Seep-associated king crabs were the keystone group in the seep model. These crabs not only transferred energy from lower trophic levels to top predators but also linked energy from seeps to neighboring deep-sea ecosystems. However, the low number of trophic connections between the seep animals and neighboring deep-sea communities indicates the uniqueness of the seep ecosystems in the deep sea. All the biomass, matter flow and trophic transfer efficiency values were higher in the seep model than in the model without seeps. The higher overhead/capacity ratio in the seep model than in the model without seeps suggests that the former model was more resilient to perturbations than the latter model. Although the net primary production and matter flow in the seep model were lower than those in the shallow-sea models, the models had comparable values of biomass excluding detritus. The relatively high system omnivory indices and low matter cycling of both deep-sea models indicate that these models were more mature than the shallow-sea models. Collectively, our deep-sea models combined with other models suggest that deep-sea ecosystems are characterized by slow dynamics and high environmental stability. This study reports the first Ecopath model for methane seep ecosystems, which may serve as a basis for potential anthropogenic impact assessment and ecosystem-based management.Liu, A.G., Dunn, F.S., 2020. Filamentous connections between Ediacaran fronds. Current Biology 30, 1322-1328. of the Ediacaran macrobiota (~571~539 mya) record phylogenetically diverse marine palaeocommunities, including early animals, which pre-date the"Cambrian Explosion". Benthic forms with a frondose gross morphology, assigned to the morphogroups Rangeomorpha and Frondomorpha (see also Arboreomorpha) are among the most temporally wide-ranging and environmentally tolerant members of the Ediacaran macrobiota [6] and dominated deep-marine ecosystems ~571~560 mya. Investigations into the morphology, palaeoecology, reproductive strategies, feeding methods, and morphogenesis of frondose taxa together constrain their phylogenetic position to the metazoan (for Rangeomorpha) or eumetazoan (e.g., Arborea) total groups, but tighter constraint is currently lacking. Here, we describe fossils of abundant filamentous organic structures preserved among frond-dominated fossil assemblages in Newfoundland (Canada). The filaments constitute a prominent component of the ecosystems, and exhibit clear physical associations with at least seven frondose taxa. Individual specimens of one uniterminal rangeomorph taxon appear to be directly connected by filaments across distances of centimeters to meters. Such physical linkages are interpreted to reflect evidence for stolonic connections: a conclusion with potential implications for the phylogenetic placement and palaeoecology of frondose organisms. Consideration of extant stoloniferous organisms suggests that Ediacaran frondose taxa were likely clonal and resurrects the possibility that they may have been colonial.Liu, B., Yang, X., Sheng, M., Yang, Z., Qiu, J., Wang, C., He, J., 2020. Sphingobacterium olei sp. nov., isolated from oil-contaminated soil. International Journal of Systematic and Evolutionary Microbiology 70, 1931-1939. Gram-stain-negative, rod-shaped, non-motile and non-spore-forming bacterium, designated HAL-9T, was isolated from oil-contaminated soil in Daqing oilfield, Heilongjiang Province, PR China. Strain HAL-9T was able to degrade quizalofop-p-ethyl and diclofop-methyl. Growth was observed at 10–35?°C (optimum, 30?°C), pH 6.0–10.0 (optimum, pH 7.0) and salinity of 0 %–5.0?% (w/v; optimum 1.0 %). The results of phylogenetic analysis based on the 16S rRNA gene indicated that strain HAL-9T belongs to the genus Sphingobacterium and showed the highest sequence similarity (98.3 %) to Sphingobacterium alkalisoli Y3L14T, followed by Sphingobacterium mizutaii DSM 11724T (95.1 %) and Sphingobacterium lactis DSM 22361T (95.1 %). Menaquinone-7 (MK-7) was the only isoprenoid quinone. The predominant cellular fatty acids were summed feature 3 (C16?:?1 ω7c and/or C16?:?1 ω6c), iso-C15:?0 and iso-C17?:?0 3-OH. The major polar lipids were phosphatidylethanolamine, three phosphoglycolipids and three unidentified lipids. The draft genome of strain HAL-9T was 5.41?Mb. The G+C?content of strain HAL-9T was 40.6?mol%. Furthermore, the average nucleotide identity and in silico DNA–DNA hybridization values between strain HAL-9T and S. alkalisoli Y3L14T were 86.2?% and 32.8 %, respectively, which were below the standard thresholds for species differentiation. On the basis of phenotypic, genotypic and phylogenetic evidence, strain HAL-9T represents a novel species in the genus Sphingobacterium , for which the name Sphingobacterium olei sp. nov. is proposed. The type strain is HAL-9T (=ACCC 61581T=CCTCC AB 2019176T=KCTC 72287T).Liu, L.-L., Hsieh, C.-Y., Kuo, M.-Y., Chen, C., Shau, Y.-H., Lui, H.-K., Yuan, C.-S., Chen, C.-T.A., 2020. Evidence for fossil fuel PM1 accumulation in marine biota. Environmental Science & Technology 54, 4068-4078. fine particulates such as those with a diameter of approximately 1 μm (particulate matter, PM1) are released from fossil fuel combustion into the air, they warm the atmosphere and contribute to millions of premature deaths in humans each year. Considerable quantities of PM1 eventually enter the oceans as suspended particulates, yet subsequent removal mechanisms are poorly understood. In fact, the presence of PM1 in marine biota has never been reported. Since sea anemones are opportunistic suspension feeders, they are anticipated to incorporate and accumulate PM1 in their bodies. By histological examination, PM1 was detected in 21 of the 22 sea anemones collected from Taiwan and Southeast China, with a depth of intertidal zone to 1000 m. PM1, if present, was always detected in endodermal layers and had the same dominant color (i.e., black, brown, or green) in different species from the same site. The bioaccumulation factor of PM1 in sea anemones was approximately 5–7 orders of magnitude. Based on radioisotope 14C results, the contribution of fossil fuel source PM1 was 8–24%. Regardless of PM1’s color, S and Fe were commonly detected by scanning electron microscopy and energy-dispersive spectrometry (SEM-EDS), suggesting anthropogenic sources. Furthermore, a maternal transfer of materials was suggested based on the existence of PM1 in sea anemone eggs and in brooding and released juveniles. The significance of PM1 accumulation by biota in aquatic ecosystems and the potential risk to living organisms via food webs warrant further investigation.Liu, L., Chen, H., Yu, Z., Zhu, D., He, Y., Liu, J., Zhu, Q., Liu, X., Liu, L., 2020. Peatland development and carbon dynamics since the Last Glacial Maximum in the Hengduan Mountains Region. CATENA 190, 104525. serve as a large carbon (C) reservoir in the biosphere. Knowledge of their initiation, expansion and peat-accumulation can help predicting peat carbon fate under climate change scenarios. This study presented a data synthesis of peatland basal ages, area changes and C accumulation rate variations in the Hengduan Mountains Region (HDMR) since the Last Glacial Maximum. The HDMR peatlands showed initiation peaks at 14.5–13 ka BP, 12–10 ka BP and 7.5–5 ka BP; these three peaks are similar, respectively, to the peaks for Southern, Northern and Tropical peatlands. The peat C accumulation rates in the HDMR ranged from 3.6 to 118.3 g C m?2 yr?1, with a mean value of 34.9 g C m?2 yr?1. Mean peat C accumulation in the HDMR peatlands during the Last Glacial Maximum was 34.7 g C m?2 yr?1 in the North and 41.5 g C m?2 yr?1 in the South. We estimate the C pool to be 1.95 Pg over the entire HDMR peatlands, with 1.73 Pg in the North and 0.22 Pg in the South. Our results suggest that the widespread peatland initiation and rapid peat accumulation in the HDMR reflect the regional environmental conditions.Liu, M., Li, W., Ruan, S., Fei, Y., 2020. N-doped hierarchical mesoporous carbon from mesophase pitch and polypyrrole for supercapacitors. Energy & Fuels 34, 5044-5051. hierarchical mesoporous carbons have been fabricated by using mesophase pitch (MP) as a carbon precursor and polypyrrole as a nitrogen resource through the MCM-48 template. Carbonization temperature plays a key role in the morphology, mesoporous structure, and electrochemical properties of N-doped porous carbons (NPCs). At an appropriate carbonization temperature (700 °C), as-prepared NPC-700 exhibits rich nitrogen content (4.48 wt %), medium specific surface area (495.9 m2 g–1), and high specific capacitance of 232.2 F g–1 at a current density of 2 A g–1 in a three-electrode system. Due to the generation of pseudocapacitance, the specific capacitance of NPC-700 is 53.6 F g–1 higher than that of PC-700 without polypyrrole. In addition, NPC-700 shows high specific capacitance of 110.6 F g–1 at a current density of 0.2 A g–1, a good capacitance retention of 77.8% at the current density of 5 A g–1, and the large energy density of 15.30 Wh kg–1 at a power density of 399.9 W kg–1 in a two-electrode system. This work provides a novel example of how N-doped porous carbons derived from mesophase pitch and polypyrrole can be used as a promising electrode material for potential energy storage applications.Liu, Q., Peng, W., Li, J., Wu, X., 2020. Source and distribution of mercury in natural gas of major petroliferous basins in China. Science China Earth Sciences 63, 643-648. on the analysis of the natural gas samples of 146 wells from four major petroliferous basins of China, the source and distribution of mercury in natural gas in major petroliferous basins of China were identified. Studies have shown that the mercury concentration of natural gas in petroliferous basins of China varies widely, ranging from 0.01 to 4050 ?g/m3. The gas well with the highest mercury concentration is in the Xushen gas field in the Songliao Basin. The mercury concentration in the craton basin is relatively low, and the secondary gas reservoir in the Tarim Basin has the lowest mercury concentration. In the rift basin, due to the presence of deep faults which cut the basement and mixing effects of deep fluids, the mercury concentration in natural gas may be abnormally high, e.g. the Xushen gas field in the Songliao Basin. In relatively stable basins where deep and large faults do not develop, mercury is primarily of organic origin. In rift basins where deep fluids are mixed with gas reservoirs, mercury in natural gas may mainly come from the deep fluids and is characterized by abnormally high mercury concentration and R/Ra values.Liu, Y.-F., Chen, J., Zaramela, L.S., Wang, L.-Y., Mbadinga, S.M., Hou, Z.-W., Wu, X.-L., Gu, J.-D., Zengler, K., Mu, B.-Z., 2020. Genomic and transcriptomic evidence supports methane metabolism in Archaeoglobi. mSystems 5, e00651-19.: Euryarchaeal lineages have been believed to have a methanogenic last common ancestor. However, members of euryarchaeal Archaeoglobi have long been considered nonmethanogenic and their evolutionary history remains elusive. Here, three high-quality metagenomic-assembled genomes (MAGs) retrieved from high-temperature oil reservoir and hot springs, together with three newly assembled Archaeoglobi MAGs from previously reported hot spring metagenomes, are demonstrated to represent a novel genus of Archaeoglobaceae, “Candidatus Methanomixophus.” All “Ca. Methanomixophus” MAGs encode an M methyltransferase (MTR) complex and a traditional type of methyl-coenzyme M reductase (MCR) complex, which is different from the divergent MCR complexes found in “Ca. Polytropus marinifundus.” In addition, “Ca. Methanomixophus dualitatem” MAGs preserve the genomic capacity for dissimilatory sulfate reduction. Comparative phylogenetic analysis supports a laterally transferred origin for an MCR complex and vertical heritage of the MTR complex in this lineage. Metatranscriptomic analysis revealed concomitant in situ activity of hydrogen-dependent methylotrophic methanogenesis and heterotrophic fermentation within populations of “Ca. Methanomixophus hydrogenotrophicum” in a high-temperature oil reservoir.Importance: Current understanding of the diversity, biology, and ecology of Archaea is very limited, especially considering how few of the known phyla have been cultured or genomically explored. The reconstruction of “Ca. Methanomixophus” MAGs not only expands the known range of metabolic versatility of the members of Archaeoglobi but also suggests that the phylogenetic distribution of MCR and MTR complexes is even wider than previously anticipated.Liu, Y., Huang, C., Zhou, Y., Lu, Y., Ma, Q., 2020. The controlling factors of lacustrine shale lithofacies in the Upper Yangtze Platform (South China) using artificial neural networks. Marine and Petroleum Geology 118, 104350. influence of paleoenvironments on the lithofacies of lacustrine mudstone is important for both paleoenvironment reconstruction and hydrocarbon exploration. Compared with the machine learning approaches, the methods to find coupling relationships are too qualitative to be convincing. This study used the artificial neural network (ANN) approach to better understand the primary factors that control lacustrine shale lithofacies development and how paleoenvironments influence depositional processes. The neural network was trained with the back propagation training algorithm based on identified shale lithofacies (desired output) and geochemical indicators (input). The lithofacies deposited under different paleoenvironments were identified from an 80-m long core based on observations of the sediment texture and structure and biota and analyses of the mineralogy and trace elements. To confirm the primary factors of lithofacies development in J1d of the Upper Yangtze Platform, five groups of elements were selected as geochemical indicators (Sr/Ba, Zr/Rb, Sr/V, V/V + Ni, and Ba/Ca) to monitor the changes in paleosalinity, paleohydrodynamic condition, paleoclimate, paleoredox, and paleoproductivity, respectively. The element groups were selected and parameterized as inputs to constrain the lithofacies (output) boundaries using artificial neural networks (ANNs). The results of the ANN models indicate that the lacustrine lithofacies development of J1d was controlled by paleosalinity, paleohydrodynamic condition, paleoclimate, and paleoredox but not by paleoproductivity. The results of this study indicate that the primary factors of shale lithofacies development can be effectively assessed via geochemical, sedimentological, and ANN analyses.Liu, Y., Huang, H., Liu, Q., Xu, X., Cheng, H., Cheng, W., 2020. A reversed compositional pseudo-gradient in biodegraded oil column from Liaohe Basin, NE China. Marine and Petroleum Geology 117, 104378. heavy oils or tar sands are formed by microbial biodegradation and show a compositional gradient toward the base of oil column. However, a reversed pseudo-gradient has been observed from the fourth member of the Shahejie Formation in Shuguang oilfield, Liaohe Basin, NE China, on the basis of bulk and molecular compositions in a series core extracts from well K037. The bulk compositions show systematic depletion of saturated hydrocarbons and enrichment of polars (resins?+?asphaltenes) toward the top of the oil column. Molecular compositions illustrate that these extracts have similar source input, depositional environment and thermal maturity, and their compositional differences are mainly caused by varying degrees of biodegradation. Biodegradation removes all n-alkanes, most isoprenoid alkanes, partial alkylnaphthalenes and alkylphenanthrenes at the top of oil column, whereas only n-alkanes are affected at the bottom. Reservoir temperature has no crucial impact on biodegradation levels as the whole oil column in the temperature range of 41–44?°C is ideal for microbial activities. The studied reservoir is not a continuous oil column, which is separated by a few barriers and baffles. The occurrence of locally high-water saturation layers caused multiple small gradients in the mid and lower part of oil column with a normal biodegradation gradient in the lowermost compartmentalized interval. The overall reversed compositional pseudo-gradient is controlled by a generally upward coarsening sedimentary sequence and the existence of top water situated at a lithology change boundary from coarse sandstones and conglomerates to fine grained sandstones. This study provides a new perspective to assess the reservoir fluid heterogeneity and sheds the light on sweet spots identification for heavy oil exploration and development.Liu, Y., Yan, L., Lv, P., Ren, L., Kong, J., Wang, J., Li, F., Bai, Y., 2020. Effect of n-hexane extraction on the formation of light aromatics from coal pyrolysis and catalytic upgrading. Journal of the Energy Institute 93, 1242-1249. order to investigate the effect of aliphatics in coal on the formation of light aromatics (benzene, toluene, ethylbenzene, xylene and naphthalene, called BTEXN) from coal pyrolysis and catalytic upgrading using on-line Py-GC/MS, n-hexane was used to extract Shengli lignite (SL) and Pingshuo bituminous coal (PS). The extracts of the two coals (SLE and PSE) were analyzed by GC×GC-MS. Results show that aliphatics account for 85% of SLE and 68% of PSE. It brings about that the total yields of BTEXN from SL residue and PS residue pyrolysis are decreased by 29% and 18% compared with raw coals. This is because the aliphatics could provide small-molecule free radicals to stabilize the light aromatic cracking fragments and promote the formation of BTEXN during pyrolysis. The amounts of the alkyl benzene series, phenols, and polycyclic aromatic hydrocarbons from pyrolysis gaseous tar are significantly increased after extraction and they will undergo catalytic cracking to form BTEXN over USY zeolite, resulting in that the total yield of BTEXN from residue is almost same as that from raw coal during catalytic upgrading.Liu, Z., Cao, L., Zhou, T., Dong, Z., 2020. Multiscale investigation of moisture-induced structural evolution in asphalt–aggregate interfaces and analysis of the relevant chemical relationship using atomic force microscopy and molecular dynamics. Energy & Fuels 34, 4006-4016. changes and intermolecular interactions in asphalt dominate the molecular reorganization and cause the evolution of micro- and mesostructures. Given the lack of knowledge regarding the molecular chemistry–microstructure relationship of the asphalt–aggregate interface, the moisture-induced adhesive failure occurring at this interface has not been fully understood. This study investigates the multiscale structures of the asphalt–aggregate interfaces exposed to water and establishes the relationship between the structures and molecular interactions. The meso- and micromorphologies of two types of treated interfacial asphalts were observed via optical microscopy and atomic force microscopy. The results show an undulated surface and boundary retreat in asphalts because of the overall interfacial tension. Dispersed microbumps measuring tens of nanometers in height progressively grow until they merge into large bumps with increasing water exposure depending on the types of asphalt and aggregates. Fourier transform infrared (FTIR) spectrometry results show enriched polar components at the surface of the treated interfacial asphalt and water diffusion driven by complex intermolecular forces. The molecular behavior simulated by molecular dynamics calculations reveals that aliphatic molecules amalgamate into nonpolar clusters, while polar molecules migrate out and act as a surfactant to stabilize the asphalt–water system driven by the interfacial tension gradient. Internal coalescence of nonpolar components results in protrusion of the asphalt’s surface, and the migration of polar components to the surface accounts for the increased absorption peaks of the polar groups. This phenomenon could explain the FTIR spectra and formation of microbumps. The state of absorbed water and nanostructures of the interfacial asphalt are dominated by intermolecular interactions among asphalt, water, and aggregates. This study provides deep insights into the structural evolution of asphalt from the chemical and molecular perspectives.Lofthus, S., Bakke, I., Tremblay, J., Greer, C.W., Brakstad, O.G., 2020. Biodegradation of weathered crude oil in seawater with frazil ice. Marine Pollution Bulletin 154, 111090. ice extent in the Arctic is declining, oil and gas activities will increase, with higher risk of oil spills to the marine environment. To determine biotransformation of dispersed weathered oil in newly formed ice, oil dispersions (2–3?ppm) were incubated in a mixture of natural seawater and frazil ice for 125?days at ?2?°C. Dispersed oil in seawater without frazil ice were included in the experimental setup. Presence or absence of frazil ice was a strong driver for microbial community structures and affected the rate of oil degradation. n-alkanes were degraded faster in the presence of frazil ice, the opposite was the case for naphthalenes and 2–3 ring PAHs. No degradation of 4–6 ring PAHs was observed in any of the treatments. The total petroleum oil was not degraded to any significant degree, suggesting that oil will freeze into the ice matrix and persist throughout the icy season.Logares, R., Deutschmann, I.M., Junger, P.C., Giner, C.R., Krabber?d, A.K., Schmidt, T.S.B., Rubinat-Ripoll, L., Mestre, M., Salazar, G., Ruiz-González, C., Sebastián, M., de Vargas, C., Acinas, S.G., Duarte, C.M., Gasol, J.M., Massana, R., 2020. Disentangling the mechanisms shaping the surface ocean microbiota. Microbiome 8, 55.: The ocean microbiota modulates global biogeochemical cycles and changes in its configuration may have large-scale consequences. Yet, the underlying ecological mechanisms structuring it are unclear. Here, we investigate how fundamental ecological mechanisms (selection, dispersal and ecological drift) shape the smallest members of the tropical and subtropical surface-ocean microbiota: prokaryotes and minute eukaryotes (picoeukaryotes). Furthermore, we investigate the agents exerting abiotic selection on this assemblage as well as the spatial patterns emerging from the action of ecological mechanisms. To explore this, we analysed the composition of surface-ocean prokaryotic and picoeukaryotic communities using DNA-sequence data (16S- and 18S-rRNA genes) collected during the circumglobal expeditions Malaspina-2010 and TARA-Oceans.Results: We found that the two main components of the tropical and subtropical surface-ocean microbiota, prokaryotes and picoeukaryotes, appear to be structured by different ecological mechanisms. Picoeukaryotic communities were predominantly structured by dispersal-limitation, while prokaryotic counterparts appeared to be shaped by the combined action of dispersal-limitation, selection and drift. Temperature-driven selection appeared as a major factor, out of a few selected factors, influencing species co-occurrence networks in prokaryotes but not in picoeukaryotes, indicating that association patterns may contribute to understand ocean microbiota structure and response to selection. Other measured abiotic variables seemed to have limited selective effects on community structure in the tropical and subtropical ocean. Picoeukaryotes displayed a higher spatial differentiation between communities and a higher distance decay when compared to prokaryotes, consistent with a scenario of higher dispersal limitation in the former after considering environmental heterogeneity. Lastly, random dynamics or drift seemed to have a more important role in structuring prokaryotic communities than picoeukaryotic counterparts.Conclusions: The differential action of ecological mechanisms seems to cause contrasting biogeography, in the tropical and subtropical ocean, among the smallest surface plankton, prokaryotes and picoeukaryotes. This suggests that the idiosyncrasy of the main constituents of the ocean microbiota should be considered in order to understand its current and future configuration, which is especially relevant in a context of global change, where the reaction of surface ocean plankton to temperature increase is still unclear.Longbottom, T.L., Hockaday, W.C., Daigle, H., Harvey, O.R., 2020. Organic chemical structure relationships to maturity and stability in shales. International Journal of Coal Geology 223, 103448. systematic understanding of organic matter chemical structure-thermal stability relationships is central to resource outcomes in sedimentary basins. This study integrates molecular spectroscopy (solid-state 13C NMR) and step-wise isothermal analysis (isoTGA) in elucidating key structure-maturity-stability relationships in shales containing type I and II kerogens (Green River and Eagle Ford Formations, respectively) that were subjected to simulated maturation via hydrous pyrolysis. Hydrous pyrolysis temperatures ranged from 250 to 400 °C – the window for immature to oil generation in the catagenic process (corresponding to Easy %Ro 0.36 to 1.07). Specifically, mole fraction aromatic C (fa) revealed strong correlations with pyrolysis temperature across both kerogen types, increasing 14.8 to 44.9 mol% and 19.7 to 75.2 mol% in the Green River and Eagle Ford samples, respectively. Aromatic bridgehead C (faB), a measure of aromatic ring condensation, showed limited predictive variation with maturity. The increase in aromatization/condensation was accompanied by increased pyrolytic cracking of alkyl C (fal), which decreased from 66.2 to 42.9 mol% in the Green River and 56.1 to 12.2 mol% in the Eagle Ford kerogen. Our 13C NMR analyses of the kerogens revealed empirical relationships that can be used for predicting pyrolysis temperature and maturity (Easy %Ro) based on the major organic structural properties of kerogen. Step-wise, isothermal thermogravimetric analyses allowed for the estimation of kinetic parameters associated with catagenesis: activation energy (Ea) and frequency factor (A). Thermal decomposition of kerogen was revealed to be a two-stage process, and increasing maturity generally resulted in an increase of thermal stability/activation energy. First-stage activation energies (Ea1) ranged 64.0 to 44.7 kJ mol?1, while second-stage activation energies (Ea2) ranged 151.4 to 198.9 kJ mol?1 with increasing maturity in the Green River samples. Similarly, Ea1 and Ea2 of the Eagle Ford ranged 13.1 to 46.0 kJ mol?1 and 208.0 to 286.2 kJ mol?1, respectively. The quantitative determination of covariation in organic structure and thermal stability of kerogen with increasing maturity can be useful in further parameterizing Basin and Petroleum System Models (BPSMs). Furthermore, these results can support the development of computational models of petroleum generation and further facilitate the experimentally-driven understanding of the interplay between organic structure and thermal stability in petroleum systems.López-García, P., Moreira, D., 2020. The Syntrophy hypothesis for the origin of eukaryotes revisited. Nature Microbiology 5, 655-667. discovery of Asgard archaea, phylogenetically closer to eukaryotes than other archaea, together with improved knowledge of microbial ecology, impose new constraints on emerging models for the origin of the eukaryotic cell (eukaryogenesis). Long-held views are metamorphosing in favour of symbiogenetic models based on metabolic interactions between archaea and bacteria. These include the classical Searcy’s and Hydrogen hypothesis, and the more recent Reverse Flow and Entangle–Engulf–Endogenize models. Two decades ago, we put forward the Syntrophy hypothesis for the origin of eukaryotes based on a tripartite metabolic symbiosis involving a methanogenic archaeon (future nucleus), a fermentative myxobacterial-like deltaproteobacterium (future eukaryotic cytoplasm) and a metabolically versatile methanotrophic alphaproteobacterium (future mitochondrion). A refined version later proposed the evolution of the endomembrane and nuclear membrane system by invagination of the deltaproteobacterial membrane. Here, we adapt the Syntrophy hypothesis to contemporary knowledge, shifting from the original hydrogen and methane-transfer-based symbiosis (HM Syntrophy) to a tripartite hydrogen and sulfur-transfer-based model (HS Syntrophy). We propose a sensible ecological scenario for eukaryogenesis in which eukaryotes originated in early Proterozoic microbial mats from the endosymbiosis of a hydrogen-producing Asgard archaeon within a complex sulfate-reducing deltaproteobacterium. Mitochondria evolved from versatile, facultatively aerobic, sulfide-oxidizing and, potentially, anoxygenic photosynthesizing alphaproteobacterial endosymbionts that recycled sulfur in the consortium. The HS Syntrophy hypothesis accounts for (endo)membrane, nucleus and metabolic evolution in a realistic ecological context. We compare and contrast the HS Syntrophy hypothesis to other models of eukaryogenesis, notably in terms of the mode and tempo of eukaryotic trait evolution, and discuss several model predictions and how these can be tested.Lu, J., Zang, J., Meyers, P., Huang, X., Qiu, P., Yu, X., Yang, H., Xie, S., 2020. Surface soil n-alkane molecular and δD distributions along a precipitation transect in northeastern China. Organic Geochemistry 144, 104015. isotope compositions of leaf wax long-chain n-alkanes (δDalk) buried in soils have the potential to provide records of continental paleoclimatic and paleohydrological changes. However, different factors and processes influence the δDalk signature, making interpretation of the soil isotope record complicated. The relative humidity/aridity and vegetation types (C3 vs C4 plants) are two major factors responsible for the soil δDalk variations. In most cases, the interaction between relative humidity/aridity and temperature cannot be separated. Here, we analyzed the δDalk compositions in surface soils along the Northeast China Transect (NECT), where the mean annual precipitation (MAP) varies from ca. 120 to 815?mm, yet the mean annual temperature changes little, providing a setting to test the role of relative humidity/aridity in soil δDalk variations, independent of temperature changes. At the same time, the western part of the NECT, which is mainly a grassland environment, provides a test of the effects of C3 and C4 grasses on soil δDalk changes. In the semi-humid eastern NECT region, the δDalk values and their apparent fractionation relative to precipitation exhibit a strong negative correlation with the aridity index and a close relationship with soil water content. This finding supports the idea that the soil δDalk values are mainly influenced by relative aridity and that the impact of evapotranspiration, including soil evaporation and transpiration-induced 2H enrichment of woody plant leaf water, plays a vital role in shaping soil δDalk. In the semi-arid and arid western NECT region, the δDalk values and their apparent fractionations show no relationship with any environmental factors. However, in the westernmost area, soil δDalk values tend to show a negative relationship with the increasing proportion of C4 plants. This pattern probably indicates that in the arid area the soil δDalk values vary more closely with plant types than with the environmental variables. This study provides new insights into deciphering the relationship between soil δDalk values and relative humidity/aridity, and it affirms the applicability of δDalk in paleo-hydrologic reconstructions.Lucas, M., Pihlap, E., Steffens, M., Vetterlein, D., K?gel-Knabner, I., 2020. Combination of imaging infrared spectroscopy and X-ray computed microtomography for the investigation of bio- and physicochemical processes in structured soils. Frontiers in Environmental Science 8, 42. doi: 10.3389/fenvs.2020.00042. is a heterogeneous mixture of various organic and inorganic parent materials. Major soil functions are driven by their quality, quantity and spatial arrangement, resulting in soil structure. Physical protection of organic matter (OM) in this soil structure is considered as a vital mechanism for stabilizing organic carbon turnover, an important soil function in times of climate change. Herein, we present a technique for the correlative analysis of 2D imaging visible light near-infrared spectroscopy and 3D X-ray computed microtomography (μCT) to investigate the interplay of biogeochemical properties and soil structure in undisturbed soil samples. Samples from the same substrate but different soil management and depth (no-tilled topsoil, tilled topsoil and subsoil) were compared in order to evaluate this method in a diversely structured soil. Imaging spectroscopy is generally used to qualitatively and quantitatively identify OM with high spatial resolution, whereas 3D X-ray μCT provides high-resolution information on pore characteristics. The unique combination of these techniques revealed that, in undisturbed samples, OM can be found mainly at greater distances from macropores and close to biopores. However, alterations were observed because of disturbances by tillage. The correlative application of imaging infrared spectroscopic and X-ray μCT analysis provided new insights into the biochemical processes affected by soil structural changes.Luo, L., Guo, X., Zhang, Z., Chai, M., Rahman, M.M., Zhang, X., Cai, J., 2020. Insight into pyrolysis kinetics of lignocellulosic biomass: Isoconversional kinetic analysis by the modified Friedman method. Energy & Fuels 34, 4874-4881. methods are commonly used to process the thermogravimetric analysis (TGA) data and to simultaneously obtain the effective activation energies for lignocellulosic biomass pyrolysis. However, the widely used isoconversional methods may lead to some systematic problems, for example, numerical instability for the Friedman method and significant errors in the kinetic parameters for the Flynn–Wall–Ozawa and Kissinger–Akahira–Sunose methods. To avoid the above problems, a modified Friedman isoconversional method has been developed in this work to accurately determine effective activation energies for solid-state reactions, such as biomass pyrolysis reactions. Through processing theoretically simulated data of strongly varying activation energy, the modified method applying for narrow intervals of conversion degree was proven to be capable of calculating the conversion dependence of activation energy accurately and reducing the effect of data noise. The modified Friedman isoconversional method was employed to process the non-isothermal TGA data of wheat straw pyrolysis at heating rates of 2.5, 5, 10, and 20 K min–1 and the kinetic data of beech sawdust pyrolysis at 5, 10, and 20 K min–1 from the literature. The results showed that the effective activation energies for the pyrolysis of wheat straw and beech sawdust varied significantly with the degree of conversion (in the conversion range from 0.05 to 0.85, the effective activation energies for wheat straw pyrolysis varied from 154 to 379 kJ mol–1, while 155–316 kJ mol–1 was reported for beech sawdust pyrolysis).Luo, X., Zhang, L., Zhang, L., Lei, Y., Cheng, M., Shi, H., Cao, B., 2020. Heterogeneity of clastic carrier bed and hydrocarbon migration and accumulation Acta Petrolei Sinica 41, 253-272. heterogeneity of clastic sediments is common. However, in researches of the exploration-scale hydrocarbon migration and accumulation, the heterogeneity of the internal components, structure, and physical properties of the carrier bed have been neglected. As a result, the heterogeneity characteristics of the carrier bed and its effect on geofluid flow and hydrocarbon migration have not received the attention they deserve. The heterogeneity of clastic carrier bed is controlled by sedimentary structure. Obvious differential diagenesis occurs in clastic rocks during shallow burial. Permeable rocks are separated by low-permeability interbeds, showing certain spatial structure characteristics. In carrier beds with structural heterogeneity, the distribution of hydrocarbon migration pathway is very uneven and different from the hydrocarbon migration pathway in the traditional model of carrier bed with uniform macroscopic properties. The oil and gas in the carrier bed with structural heterogeneity generally migrates upwards. However, in the intervals where vertical migration should occur as originally thought, the oil and gas migrating is blocked by interbeds, and the migration pathway becomes very complicated. Lateral migration can occur in the upper, middle and lower section of carrier bed. Traps in the up dip direction are still the ultimate direction and favorable target of oil and gas migration. Oil and gas can accumulate anywhere during migration. The individual hydrocarbon accumulation is small in scale, but large in quantity and widely distributed, so the total amount of oil and gas may be much greater than that of reservoirs in high traps. In carrier beds with structural heterogeneity, the hydrocarbon migration pathway and accumulation mode are different from traditional understanding, which bring many insights to the understanding of hydrocarbon migration and accumulation process. The understanding of carrier beds with structural heterogeneity can provide more targets for petroleum exploration, and both subsags and slopes may become favorable exploration areas.Lv, J.-H., Wei, X.-Y., Zhang, Y.-Y., Zong, Z.-M., 2020. Occurrence and distribution of biomarkers in Baiyinhua lignite. Fuel 271, 117525. thermal dissolution (STD) of Baiyinhua lignite (BL) in cyclohexane, methanol, and ethanol was performed at 300 °C to characterize the biomarkers (BMs) in BL. To confirm the origin of the BMs, BL pyrolysis was investigated using a Curie-point pyrolyzer. According to the analysis with a gas chromatograph/mass spectrometer, the BMs detected can be classified into n-alkanes, isoprenoid alkanes, n-alkenes, long-chain alkylbenzenes (ABs), polyarenes, n-alkanones, alkyl-substituted cyclopentanones, and alkyl-substituted cyclopent-2-enones. Except n-alkenes, other BMs are enriched into soluble portions from the STD. The absence of n-alkenes in BL indicates that BL was formed in a mild climate during geological times. The occurrence and distribution of BMs reflect the various pathways of BMs during coalification. The distribution of n-alkanes confirms that BL is a typical non-marine coal. Long-chain n-alkenes could inherently exist in BL, while mid-chain ones were mainly produced from the cleavage of side chains on aromatic rings. In most cases, the distribution of ABs is similar to that of n-alkanes in cyclohexane-soluble portion, suggesting a product-precursor relationship between ABs and n-alkanes. The much higher relative proportion of retene than cadalene illustrates that as for high terrestrial plants, pinaceae significantly contributed to the formation of BL. Organic molecules in living organisms undergo a series of physical, chemical and biochemical changes to produce different BMs. Related mechanisms for the formation of BMs during coalification were discussed.Lv, J., Han, R., Luo, L., Zhang, X., Zhang, S., 2020. A novel strategy to evaluate the aromaticity degree of natural organic matter based on oxidization-induced chemiluminescence. Environmental Science & Technology 54, 4171-4179. to its complex composition and structure, many of the properties of natural organic matter (NOM) are poorly understood. In this study, the oxidization-induced chemiluminescence (OCL) of NOM was investigated, and a flow-injection OCL method was developed using alkaline persulfate-H2O2 as the oxidizing agent. The method is suitable for the direct analysis of NOM in both homogeneous and heterogeneous samples without isolation or concentration. A strong linear relationship (p < 0.001) was found between the normalized organic carbon OCL (OCLOC) and the percentage of aromatic carbon in standard NOM and soil samples, suggesting that OCLOC can be used as an empirical indicator to assess the aromaticity degree of NOM in both homogeneous and heterogeneous samples. By using this method, the percentages of aromatic carbon in a forest soil profile with low organic carbon content were estimated, and a decrease in the degree of aromaticity in deeper soil was observed. Considering the high sensitivity (lower than 0.1 mg C L–1) and throughput (13 s per detection) and low sample consumption (less than 1 mg) of the method, the proposed OCLOC indicator shows great promise for the high-throughput evaluation of the aromaticity degree of NOM for a wide variety of environmental and geochemical samples.Lv, W., Wang, L., Xuan, Q., Zhao, X., Liu, X., Shi, X., Xu, G., 2020. Pseudotargeted method based on parallel column two-dimensional liquid chromatography-mass spectrometry for broad coverage of metabolome and lipidome. Analytical Chemistry 92, 6043-6050. and lipid profilings usually need two liquid chromatography-mass spectrometry (LC-MS) methods because of a great polarity difference. A pseudotargeted metabolomics method as a novel emerging approach can integrate the advantages of nontargeted and targeted methods. Here, we aim to establish a comprehensive method for metabolome and lipidome by using a parallel column-based two-dimensional LC (PC-2DLC)-MS and pseudotargeted approach. To simultaneously extract as many polar metabolites and nonpolar lipids as possible, we systematically optimized the sample pretreatment process, and isopropanol/methanol (3:1, v/v) and isopropanol/water (7:3, v/v) were selected as the extraction and reconstitution solvents, respectively. The detected triglycerides significantly increased after the sample pretreatment optimization. Then PC-2DLC coupled with Triple TOF MS was applied to analyze a mixed sample from serum, urine, and liver tissue matrixes. The multiple reaction monitoring (MRM) transitions of the metabolome and lipidome were defined according to the “MRM-Ion Pair Finder” software and lipidomics MRM-transition database, respectively. After verification by QTRAP MS in the scheduled MRM mode, 1609 potential metabolites and lipids corresponding to 1294 MRM transitions, and 847 potential metabolites and lipids corresponding to 687 MRM transitions were detected in positive and negative ion modes, respectively. They range at about 30 orders of magnitude in octanol/water partition coefficient. The pseudotargeted 2DLC-MS method was validated to have good analytical characteristics. As a proof of applicability, sera from type 2 diabetic patients were investigated by the established method. The results indicated that the pseudotargeted 2DLC-MS method is reliable and repeatable and can be used in a metabolomics study.Ma, C., Lin, C., Dong, C., Luan, G., Zhang, Y., Sun, X., Liu, X., 2020. Quantitative relationship between argillaceous caprock thickness and maximum sealed hydrocarbon column height. Natural Resources Research 29, 2033-2049. quality of a caprock is closely related to its thickness. Statistical data show that there is an obvious positive correlation between caprock thickness and hydrocarbon column height. This report established that the starting pressure gradient is the key factor in the relationship between caprock thickness and hydrocarbon column height by discussing the concepts and principles of breakthrough pressure, capillary pressure, and starting pressure. Analysis of the physical–chemical properties of the surfaces of mineral particles revealed that the structure of the diffused electric double layer stably develops in the pore throat at the micro- to nanoscale. This is a microcosm of the starting pressure generated in the argillaceous caprock. Based on force analysis, this report establishes that in the process by which fluid breaks through the argillaceous caprock, hydrocarbons slowly displace the formation water in the pore throats and mainly overcome the capillary pressure and adsorption resistance. The quantitative relationship between the caprock thickness and the maximum hydrocarbon column height is determined by considering the starting pressure gradient, and a method is proposed to calculate the maximum hydrocarbon column height of the caprock based on the formation overpressure. This method is successfully applied, and verification via gas testing is performed for offshore oil and gas fields by considering the X gas reservoir. The proposed method has good application prospects in the evaluation of argillaceous caprocks and reservoir risk prediction.Maerz, J., Six, K.D., Stemmler, I., Ahmerkamp, S., Ilyina, T., 2020. Microstructure and composition of marine aggregates as co-determinants for vertical particulate organic carbon transfer in the global ocean. Biogeosciences 17, 1765-1803. aggregates are the vector for biogenically bound carbon and nutrients from the euphotic zone to the interior of the oceans. To improve the representation of this biological carbon pump in the global biogeochemical HAMburg Ocean Carbon Cycle (HAMOCC) model, we implemented a novel Microstructure, Multiscale, Mechanistic, Marine Aggregates in the Global Ocean (M4AGO) sinking scheme. M4AGO explicitly represents the size, microstructure, heterogeneous composition, density and porosity of aggregates and ties ballasting mineral and particulate organic carbon (POC) fluxes together. Additionally, we incorporated temperature-dependent remineralization of POC. We compare M4AGO with the standard HAMOCC version, where POC fluxes follow a Martin curve approach with (i) linearly increasing sinking velocity with depth and (ii) temperature-independent remineralization. Minerals descend separately with a constant speed. In contrast to the standard HAMOCC, M4AGO reproduces the latitudinal pattern of POC transfer efficiency, as recently constrained by Weber et al. (2016). High latitudes show transfer efficiencies of ?≈?0.25±0.04, and the subtropical gyres show lower values of about 0.10±0.03. In addition to temperature as a driving factor for remineralization, diatom frustule size co-determines POC fluxes in silicifier-dominated ocean regions, while calcium carbonate enhances the aggregate excess density and thus sinking velocity in subtropical gyres. Prescribing rising carbon dioxide (CO2) concentrations in stand-alone runs (without climate feedback), M4AGO alters the regional ocean atmosphere CO2 fluxes compared to the standard model. M4AGO exhibits higher CO2 uptake in the Southern Ocean compared to the standard run, while in subtropical gyres, less CO2 is taken up. Overall, the global oceanic CO2 uptake remains the same. With the explicit representation of measurable aggregate properties, M4AGO can serve as a test bed for evaluating the impact of aggregate-associated processes on global biogeochemical cycles and, in particular, on the biological carbon pump.Mak, T.D., Goudarzi, M., Laiakis, E.C., Stein, S.E., 2020. Disparate metabolomics data reassembler: A novel algorithm for agglomerating incongruent LC-MS metabolomics datasets. Analytical Chemistry 92, 5231-5239. the past decade, the field of LC-MS-based metabolomics has transformed from an obscure specialty into a major “-omics” platform for studying metabolic processes and biomolecular characterization. However, as a whole the field is still very fractured, as the nature of the instrumentation and the information produced by the platform essentially creates incompatible “islands” of datasets. This lack of data coherency results in the inability to accumulate a critical mass of metabolomics data that has enabled other -omics platforms to make impactful discoveries and meaningful advances. As such, we have developed a novel algorithm, called Disparate Metabolomics Data Reassembler (DIMEDR), which attempts to bridge the inconsistencies between incongruent LC-MS metabolomics datasets of the same biological sample type. A single “primary” dataset is postprocessed via traditional means of peak identification, alignment, and grouping. DIMEDR utilizes this primary dataset as a progenitor template by which data from subsequent disparate datasets are reassembled and integrated into a unified framework that maximizes spectral feature similarity across all samples. This is accomplished by a novel procedure for universal retention time correction and comparison via identification of ubiquitous features in the initial primary dataset, which are subsequently utilized as endogenous internal standards during integration. For demonstration purposes, two human and two mouse urine metabolomics datasets from four unrelated studies acquired over 4 years were unified via DIMEDR, which enabled meaningful analysis across otherwise incomparable and unrelated datasets.Makhneva, Z.K., Ashikhmin, A.A., Bolshakov, M.A., Moskalenko, A.A., 2020. Carotenoids are probably involved in singlet oxygen generation in the membranes of purple photosynthetic bacteria under light irradiation. Microbiology 89, 164-173. possibility of singlet oxygen generation in five species of photosynthetic bacteria under irradiation with light was studied using the Singlet Oxygen Sensor Green (SOSG) dye that, when singlet oxygen is bound, is transformed into a fluorescent endoperoxide form. Irradiation was carried out using light of different spectral composition: red (absorption of bacteriochlorophyll, BChl) and white (absorption of BChl and carotenoids). No singlet oxygen generation was detected under red light irradiation, which indicated that BChl was not involved in this process. Under white light, as the irradiation time increased, an increase in SOSG fluorescence was recorded in the membranes of four bacterial species: Allochromatium vinosum MSU, Rhodobacter sphaeroides G1C, Rba. blasticus K-1 and Rhodopseudomonas faecalis. In Rba. sphaeroides, no increase in SOSG fluorescence was observed. It is assumed that in the white light this process occurs due to the pigments that absorb in the blue-green region of the spectrum, i.e. carotenoids with 8?11 conjugated double bonds (neurosporene, spheroidene, lycopene, and rhodopin). Similar to Trolox, SOSG may slow down the bleaching process of BChl850 in the membranes of Alc. vinosum strain MSU and may therefore effectively perform the role of a singlet oxygen trap.M?nd, K., Lalonde, S.V., Robbins, L.J., Thoby, M., Paiste, K., Kreitsmann, T., Paiste, P., Reinhard, C.T., Romashkin, A.E., Planavsky, N.J., Kirsim?e, K., Lepland, A., Konhauser, K.O., 2020. Palaeoproterozoic oxygenated oceans following the Lomagundi–Jatuli Event. Nature Geoscience 13, 302-306. approximately 2,220–2,060 million years old Lomagundi–Jatuli Event was the longest positive carbon isotope excursion in Earth history and is traditionally interpreted to reflect an increased organic carbon burial and a transient rise in atmospheric O2. However, it is widely held that O2 levels collapsed for more than a billion years after this. Here we show that black shales postdating the Lomagundi–Jatuli Event from the approximately 2,000 million years old Zaonega Formation contain the highest redox-sensitive trace metal concentrations reported in sediments deposited before the Neoproterozoic (maximum concentrations of Mo?=?1,009?μg?g?1, U?=?238?μg?g?1 and Re?=?516?ng?g?1). This unit also contains the most positive Precambrian shale U isotope values measured to date (maximum 238U/235U ratio of 0.79‰), which provides novel evidence that there was a transition to modern-like biogeochemical cycling during the Palaeoproterozoic. Although these records do not preclude a return to anoxia during the Palaeoproterozoic, they uniquely suggest that the oceans remained well-oxygenated millions of years after the termination of the Lomagundi–Jatuli Event.Manucharova, N.A., Ksenofontova, N.A., Karimov, T.D., Vlasova, A.P., Zenova, G.M., Stepanov, A.L., 2020. Changes in the phylogenetic structure of the metabolically active prokaryotic soil complex induced by oil pollution. Microbiology 89, 219-230. genetic techniques (FISH and metabarcoding) were used to investigate comparative biodiversity in the prokaryotic complex of soil microcosms of gray forest, chestnut, and chernozem soils before and after oil pollution. At the level of high-rank taxonomic units, the structure of prokaryotic communities from different soil types was similar. In oil-polluted microcosms microbial diversity decreased, and the metbolically active dominants of the Bacteria and Archaea domains changed compared to the control samples. A specific bacterial complex was found to emerge in experimental samples of all soil types, with predominance of the Gammaproteobacteria and Actinobacteria, as well as of archaea, among which Thaumarchaeota and Crenarchaeota prevailed. Members of the soil prokaryotic complex active and inactive in respect to oil pollution were determined. Our results indicate similar succession responses of microbial communities from different soil type to oil pollution.Mao, L., Chang, X., Xu, Y., Shi, B., Gao, D., 2019. Geochemical characterization and possible hydrocarbon contribution of the Carboniferous interval natively developed in the Chepaizi Uplift of Junggar Basin, northwestern China. Energy Exploration & Exploitation 38, 654-681. studies on Chepaizi Uplift mainly focused on its reservoirs, and the potential source rocks natively occurred was ignored. During the exploration process, dark mudstones and tuffaceous mudstones were found in the Carboniferous interval. These possible source rocks have caused great concern about whether they have hydrocarbon generation potential and can contribute to the reservoirs of the Chepaizi Uplift. In this paper, the potential source rocks are not only evaluated by the organic richness, type, maturity, and depositional environment, but also divided into different kinetics groups. The Carboniferous mudstones dominated by Type III kerogen were evolved into the stage of mature. Biomarkers indicate that the source rocks were deposited in a marine environment under weakly reducing conditions and received mixed aquatic and terrigenous organic matter, with the latter being predominant. The effective source rocks are characterized by the total organic carbon values?>0.5?wt.% and the buried depth?>1500?m. The tuffaceous mudstone shows a greater potential for its lower active energy and longer hydrocarbon generation time. Considering the hydrocarbon generation potential, base limits of the total organic carbon and positive correlation of oil–source rock together, the native Carboniferous mudstones and tuffaceous mudstones might contribute to the Chepaizi Uplift reservoirs of the northwestern region of the Junggar Basin, especially the deeper effective source rocks should be paid enough attention to.Marcillo, A., Wei?, B.M., Widdig, A., Birkemeyer, C., 2020. Challenges of fast sampling of volatiles for thermal desorption gas chromatography - mass spectrometry. Journal of Chromatography A 1617, 460822. active sampling of volatile organic compounds (VOCs) under field conditions still is a great challenge especially when the exposure time to the source of emissions is a restricting factor. Hence, to identify ideal conditions for such applications, we systematically compared fast active sampling of VOCs collected on two common adsorbents under two regimes: first, very low gas volumes (from 300?mL) sampled at nominal flow rate and, second, sampling at the maximal applicable flow rate (0.5?L/min) before loss of sorbent material was experienced. For XAD-2 and Tenax TA, efficient sorbents for on-site VOC-sampling followed by thermal desorption GC–MS, significant differences in the signal response of volatile compounds were related not only to the varied experimental factors alone, but also to their interactions and to compound volatility. In the first regime, volatiles (～0.004–3.13?mM) from Tenax TA gave the highest signal response only above 800?mL sampled gas volume while at low concentrations (～0.004–0.12?mM), satisfactory recovery from XAD-2 required longer analyte-sorbent interaction. For the second regime, the relative recovery was severely impaired down to 73?±?23%, n?=?56 for Tenax TA and 72?±?17%, n?=?56 for XAD-2 at intermediate concentration, and 79?±?11%, n?=?84 for Tenax TA at high concentration compared to the relative recovery at standard flow rate. Neither Tenax TA nor XAD-2 provided a 100% total recovery (calculated using breakthrough values) for any of the evaluated compounds. Finally, two-way and three-way interactions identified in a multi-variable model, explained not only the dependence of the signal response on different experimental variables, but also their complex interplay affecting the recovery of the VOCs. In conclusion, we show for the first time that XAD-2, a material only recently introduced for the adsorption of volatiles from the gas phase, competes well with the standard material Tenax TA under conditions of fast sampling. Due to the similar absolute recovery with Tenax TA even at low concentration and with regard to the better detection limits, we consider XAD-2 the better choice for fast sampling of VOCs, particularly with low sample volumes at regular flow. For fast sampling with high flow rate, however, both sorbents might be selected only if the corresponding recovery loss can be accepted for the study.Marin-Carbonne, J., Busigny, V., Miot, J., Rollion-Bard, C., Muller, E., Drabon, N., Jacob, D., Pont, S., Robyr, M., Bontognali, T.R.R., Fran?ois, C., Reynaud, S., Van Zuilen, M., Philippot, P., 2020. In situ Fe and S isotope analyses in pyrite from the 3.2?Ga Mendon Formation (Barberton Greenstone Belt, South Africa): Evidence for early microbial iron reduction. Geobiology 18, 306-325. the basis of phylogenetic studies and laboratory cultures, it has been proposed that the ability of microbes to metabolize iron has emerged prior to the Archaea/Bacteria split. However, no unambiguous geochemical data supporting this claim have been put forward in rocks older than 2.7–2.5 giga years (Gyr). In the present work, we report in situ Fe and S isotope composition of pyrite from 3.28‐ to 3.26‐Gyr‐old cherts from the upper Mendon Formation, South Africa. We identified three populations of microscopic pyrites showing a wide range of Fe isotope compositions, which cluster around two δ56Fe values of ?1.8‰ and +1‰. These three pyrite groups can also be distinguished based on the pyrite crystallinity and the S isotope mass‐independent signatures. One pyrite group displays poorly crystallized pyrite minerals with positive Δ33S values > +3‰, while the other groups display more variable and closer to 0‰ Δ33S values with recrystallized pyrite rims. It is worth to note that all the pyrite groups display positive Δ33S values in the pyrite core and similar trace element compositions. We therefore suggest that two of the pyrite groups have experienced late fluid circulations that have led to partial recrystallization and dilution of S isotope mass‐independent signature but not modification of the Fe isotope record. Considering the mineralogy and geochemistry of the pyrites and associated organic material, we conclude that this iron isotope systematic derives from microbial respiration of iron oxides during early diagenesis. Our data extend the geological record of dissimilatory iron reduction (DIR) back more than 560 million years (Myr) and confirm that micro‐organisms closely related to the last common ancestor had the ability to reduce Fe(III).Martins, C.M.S., Cerqueira, J.R., Ribeiro, H.J.P.S., Garcia, K.S., da Silva, N.N., Queiroz, A.F.d.S., 2020. Evaluation of thermal effects of intrusive rocks on the kerogen present in the black shales of Irati Formation (Permian), Paraná Basin, Brazil. Journal of South American Earth Sciences 100, 102559. samples from outcrops of the Irati Formation (Permian), Paraná Basin, Brazil were analyzed based on organic geochemistry, palynofacies, and stable carbon isotopes with the aim of evaluating thermal effects of igneous intrusions on the kerogen. The potential for hydrocarbon generation, the depositional paleoenvironment, and the input of the organic matter were also studied. Most samples have high total organic carbon content, excellent hydrocarbon source potential, and type I kerogen, except some samples which showed changes in their compositional characteristic due alteration in the depositional paleoenvironment and due to the high maturation caused by the heat of diabase intrusions. The composition and distribution of saturate and aromatic biomarkers and stable carbon isotopes provided evidence that the composition of organic matter in the shales is marine, except at the upper part of the outcrops where the shales have contribution of terrestrial organic matter. Saturate biomarkers results indicated thermal immaturity for hydrocarbon generation, except the samples that were influenced by the heat of intrusive rocks.Mathews, R.P., Pillai, S.S.K., Manoj, M.C., Agrawal, S., 2020. Palaeoenvironmental reconstruction and evidence of marine influence in Permian coal-bearing sequence from Lalmatia Coal mine (Rajmahal Basin), Jharkhand, India: A multi-proxy approach. International Journal of Coal Geology 224, 103485. coal-bearing sequences belong to the Barakar Formation (Permian) of Lower Gondwana. The well-developed coal-bearing sequences (approx. 52 m) exposed along the mine section have been studied to understand the depositional environment. Along with this, a cuticle study was performed to understand the palaeoclimate with the help of the stomatal index. The distribution of n–alkanes (n–C15 to n–C31) suggests major higher plant and algal dominant source input, although variations are seen in the relative input. Steranes identified include C29 regular sterane and 4-Methylsteranes. The Pr/Ph ratio varied from 0.43 to 4.26. Warm temperate to subtropical palaeoclimate with fresh to brackish water bodies, and reducing oxygen-poor environment were inferred from the Rb/Sr, Sr/Cu, Th/U, Sr/Ba, V/(V+Ni). Mean δ13C value measured is ?23.0‰ ± 0.60‰ for coal and ?22.6‰ for shale. These values are well correlated with typical δ13C values of the Permian coal and shale. The stomatal index of Glossopteris leaves (280 million years) was taken into account, and it showed a value of 10.7 that assumes a higher level of atmospheric CO2 during the Barakar Formation (Artinskian age). The result also shows that Permian taxon Glossopteris can be used for CO2–proxy during Permian age. The geochemical evidence suggests that towards the middle part (middle coal seam) of the studied section, the depositional milieu was under a marine-influenced marginal condition. The geochemical studies and carbon isotopic ratios unequivocally suggest that fluctuating climatic conditions existed during the deposition of the Lalmatia coal-bearing sequence.Matjuschkin, V., Woodland, A.B., Frost, D.J., Yaxley, G.M., 2020. Reduced methane-bearing fluids as a source for diamond. Scientific Reports 10, 6961. formation in the Earth has been extensively discussed in recent years on the basis of geochemical analysis of natural materials, high-pressure experimental studies, or theoretical aspects. Here, we demonstrate experimentally for the first time, the spontaneous crystallization of diamond from CH4-rich fluids at pressure, temperature and redox conditions approximating those of the deeper parts of the cratonic lithospheric mantle (5–7?GPa) without using diamond seed crystals or carbides. In these experiments the fluid phase is nearly pure methane, even though the oxygen fugacity was significantly above metal saturation. We propose several previously unidentified mechanisms that may promote diamond formation under such conditions and which may also have implications for the origin of sublithospheric diamonds. These include the hydroxylation of silicate minerals like olivine and pyroxene, H2 incorporation into these phases and the “etching” of graphite by H2 and CH4 and reprecipitation as diamond. This study also serves as a demonstration of our new high-pressure experimental technique for obtaining reduced fluids, which is not only relevant for diamond synthesis, but also for investigating the metasomatic origins of diamond in the upper mantle, which has further implications for the deep carbon cycle.McCalley, C.K., 2020. Methane-eating microbes. Nature Climate Change 10, 275-276. Arctic methane emissions depend partly on interactions between soil carbon released during permafrost thaw and microbial physiology. Now, a model shows potential increased methane produced from thawing permafrost carbon could be offset by increased consumption by upland methanotrophs./articles/s41558-020-0736-x.pdfRising global temperatures are drawing increasing attention to the Arctic, where climate warming is most intense and permanently frozen ice sheets and soil are disappearing. Carbon that has been trapped in frozen soils for millennia is now becoming available to microorganisms, and there is mounting concern over how much will be released back to the atmosphere as the greenhouse gases carbon dioxide and methane. Increased activity of methane-producing microorganisms in thawing permafrost could potentially yield large emissions of this potent greenhouse gas to the atmosphere1. However, consumption of methane by bacteria living in upland mineral soils has recently been identified as a process that may substantially reduce overall high-latitude emissions2. Writing in Nature Climate Change, Youmi Oh, Qianlai Zhuang and colleagues3 incorporate this new understanding of microbial activity into a new model that estimates much lower Arctic methane release. The model predicts that increases in methane oxidation with rising temperature could cause a decrease in Arctic methane emissions under climate change.A fundamental challenge for improving predictions of future climate has long been our understanding of the variability in the sinks and sources of methane. Arctic ecosystems in particular are a large, yet poorly understood source of methane that are undergoing rapid change4,5. The methane flux to the atmosphere represents the combination of production, oxidation and transport, all of which respond differently to climate change, making it essential to accurately include these mechanisms in ecosystem models. When compared with modelling approaches that build upon direct observations of the atmosphere, models that simulate the processes involved in methane emission overestimate fluxes from natural ecosystems by as much as 5–10 Tg CH4 yr–1 (refs. 6,7). This discrepancy points to the existence of key unknowns in the depiction of methane cycling.Representation of microbial activity is increasingly being recognized as one of the solutions to closing the gap between model simulations and observational data. This includes rates and efficiencies of microbial processes, distributions of key functional microbial groups and more individualized responses to environmental conditions. Further, when making projections of feedbacks between permafrost loss and greenhouse gas emissions, the focus has been exclusively on processes and microorganisms in organic-rich Arctic soils. Yet these environments high in organic content are only 13% of total Arctic land area, with the remaining 87% being mineral-rich soils. Mineral soils at high latitudes have recently been shown to support populations of high-affinity methanotrophs — bacteria that consume atmospheric methane and therefore act as an Arctic methane sink8. These bacteria are also more temperature-sensitive than microbes that produce methane9, suggesting that they will have a stronger response to climate change and could potentially mitigate some of the projected increases in methane emissions arising from permafrost thaw.Oh et al. tested whether a detailed approach to simulating microbial community dynamics and permafrost thaw in models can better match Arctic methane observations. Specifically, they considered methane oxidation in mineral soils, differences in physiology between methane-producing and oxidizing microbial communities, and changes in soil carbon availability as permafrost thaws. They compared a series of biogeochemical models, starting with the widely used Terrestrial Ecosystem Model (TEM), which includes methane production fuelled by carbon recently fixed by plants and methane consumption by microbes who require high concentrations of methane in order to be active. To this model, they added a more nuanced understanding of methane dynamics, including the high-affinity methanotrophs and methane production fuelled by soil carbon liberated from permafrost thaw. Furthermore, differences in physiology across microbial groups were added by separately simulating the growth efficiency and maintenance efficiency of methanogens and high-affinity methanotrophs.This new model brings pan-Arctic estimates of methane emissions more in line with current observational data, as well as with estimates based on inversion modelling approaches, which scale fluxes to match atmospheric measurements. This model change represents a 20% decrease in Arctic methane emissions compared with the original estimates from process-based modelling, due largely to higher simulated methane uptake in upland soils. Simulations under projected warming scenarios also show that although increased soil carbon availability and increased metabolic activity of methanogens will increase methane emissions from Arctic soils, an even stronger temperature response of methane-oxidizing communities could mitigate this, resulting in little to no increase in net methane emissions under a high warming scenario.Arctic ecosystem responses to climate change include more than just permafrost thaw (Fig. 1), and the next generation of biogeochemical models will also need to incorporate the impacts of vegetation and hydrology changes on the dynamics of the methane cycle10,11. Future model development will also need to consider the role of aquatic ecosystems, whose potentially high emissions and sensitivity to the climate could play a key role in changing methane budgets12. Oh et al., however, provide a step towards strengthening our representation of methane cycling in Arctic ecosystems and draw attention to the role that methane-oxidizing communities may play in future emissions. Their model development highlights the gains that can be made by using field and laboratory investigations of microbial communities to improve estimates of large-scale greenhouse gas emissions budgets.References1. Schuur, E. A. G. et al. Nature 520, 171–179 (2015).2. J?rgensen, C. J., Maria, K., Johansen, L., Westergaard-Nielsen, A. & Elberling, B. Nat. Geosci. 8, 20–23 (2014).3. Oh, Y. et al. Nat. Clim. Change (2020).4. Petrescu, A. M. R. et al. Global Biogeochem. Cycles 24, GB4009 (2010).5. McGuire, A. D. et al. Ecol. Monogr. 79, 523–555 (2009).6. Saunois, M. et al. Earth Syst. Sci. Data 8, 697–751 (2016).7. Bruhwiler, L. et al. Atmos. Chem. Phys. 14, 8269–8293 (2014).8. Lau, M. C. Y. et al. ISME J. 9, 1880–1891 (2015).9. D’Imperio, L., Nielsen, C. S., Westergaard-Nielson, A., Michelsen, A. & Elberling, B. Glob. Change Biol. 23, 966–976 (2017).10. Nauta, A. L. et al. Nat. Clim. Change 5, 67–70 (2015).11. Liljedahl, A. K. et al. Nat. Geosci. 9, 312–318 (2016).12. Wik, M., Varner, R. K., Anthony, K. W., MacIntyre, S. & Bastviken, D. Nat. Geosci. 9, 99–105 (2016).McClain, C.R., Webb, T.J., Nunnally, C.C., Dixon, S.R., Finnegan, S., Nelson, J.A., 2020. Metabolic niches and biodiversity: A test case in the deep sea benthos. Frontiers in Marine Science 7, 216. doi: 10.3389/fmars.2020.00216. great anthropogenic alterations occurring to carbon availability in the oceans necessitate an understanding of the energy requirements of species and how changes in energy availability may impact biodiversity. The deep-sea floor is characterized naturally by extremely low availability of chemical energy and is particularly vulnerable to changes in carbon flux from surface waters. Because the energetic requirements of organisms impact nearly every aspect of their ecology and evolution, we hypothesize that species are adapted to specific levels of carbon availability and occupy a particular metabolic niche. We test this hypothesis in deep-sea, benthic invertebrates specifically examining how energetic demand, axes of the metabolic niche, and geographic range size vary over gradients of chemical energy availability. We find that benthic invertebrates with higher energetic expenditures, and ecologies associated with high energy demand, are located in areas with higher chemical energy availability. In addition, we find that range size and location of deep-sea, benthic species is determined by geographic patterns in chemical energy availability. Our findings indicate that species may be adapted to specific energy regimes, and the metabolic niche can potentially link scales from individuals to ecosystems as well as adaptation to patterns in biogeography and biodiversity.McDevitt, B., Cavazza, M., Beam, R., Cavazza, E., Burgos, W.D., Li, L., Warner, N.R., 2020. Maximum removal efficiency of barium, strontium, radium, and sulfate with optimum AMD-Marcellus flowback mixing ratios for beneficial use in the northern Appalachian Basin. Environmental Science & Technology 54, 4829-4839. of acid mine drainage (AMD) and hydraulic fracturing flowback fluids (HFFF) could represent an efficient management practice to simultaneously manage two complex energy wastewater streams while reducing freshwater resource consumption. AMD discharges offer generally high sulfate concentrations, especially from the bituminous coal region of Pennsylvania; unconventional Marcellus shale gas wells generally yield HFFF enriched in alkaline earth metals such as Sr and Ba, known to cause scaling issues in oil and gas (O&G) production. Mixing the two waters can precipitate HFFF-Ba and -Sr with AMD-SO4, therefore removing them from solution. Four AMD discharges and HFFF from two unconventional Marcellus shale gas wells were characterized and mixed in batch reactors for 14 days. Ba could be completely removed from solution within 1 day of mixing in the form BaxSr1–xSO4 and no further significant precipitation occurred after 2 days. Total removal efficiencies of Ba + Sr + SO4 and the proportion of Ba and Sr in BaxSr1–xSO4 depended upon the Ba/Sr ratio in the initial HFFF. A geochemical model was calibrated from batch reactor data and used to identify optimum AMD–HFFF mixing ratios that maximize total removal efficiencies (Ba + Sr + SO4) for reuse in O&G development. Increasing Ba/Sr ratios can enhance total removal efficiency but decrease the efficiency of Ra removal. Thus, treatment objectives and intended beneficial reuse need to be identified prior to optimizing the treatment of HFFF with AMD.McGonigle, J.M., Lang, S.Q., Brazelton, W.J., 2020. Genomic evidence for formate metabolism by Chloroflexi as the key to unlocking deep carbon in Lost City microbial ecosystems. Applied and Environmental Microbiology 86, e02583-19.: The Lost City hydrothermal field on the Mid-Atlantic Ridge supports dense microbial life on the lofty calcium carbonate chimney structures. The vent field is fueled by chemical reactions between the ultramafic rock under the chimneys and ambient seawater. These serpentinization reactions provide reducing power (as hydrogen gas) and organic compounds that can serve as microbial food; the most abundant of these are methane and formate. Previous studies have characterized the interior of the chimneys as a single-species biofilm inhabited by the Lost City Methanosarcinales, but they also indicated that this methanogen is unable to metabolize formate. The new metagenomic results presented here indicate that carbon cycling in these Lost City chimney biofilms could depend on the metabolism of formate by Chloroflexi populations. Additionally, we present evidence for metabolically diverse, formate-utilizing Sulfurovum populations and new genomic and phylogenetic insights into the unique Lost City Methanosarcinales.Importance: Primitive forms of life may have originated around hydrothermal vents at the bottom of the ancient ocean. The Lost City hydrothermal vent field, fueled by just rock and water, provides an analog for not only primitive ecosystems but also potential extraterrestrial rock-powered ecosystems. The microscopic life covering the towering chimney structures at the Lost City has been previously documented, yet little is known about the carbon cycling in this ecosystem. These results provide a better understanding of how carbon from the deep subsurface can fuel rich microbial ecosystems on the seafloor.McLean, C., Kujawinski, E.B., 2020. AutoTuner: High fidelity and robust parameter selection for metabolomics data processing. Analytical Chemistry 92, 5724-5732. metabolomics experiments provide a snapshot of cellular metabolism but remain challenging to interpret due to the computational complexity involved in data processing and analysis. Prior to any interpretation, raw data must be processed to remove noise and to align mass-spectral peaks across samples. This step requires selection of dataset-specific parameters, as erroneous parameters can result in noise inflation. While several algorithms exist to automate parameter selection, each depends on gradient descent optimization functions. In contrast, our new parameter optimization algorithm, AutoTuner, obtains parameter estimates from raw data in a single step as opposed to many iterations. Here, we tested the accuracy and the run-time of AutoTuner in comparison to isotopologue parameter optimization (IPO), the most commonly used parameter selection tool, and compared the resulting parameters’ influence on the properties of feature tables after processing. We performed a Monte Carlo experiment to test the robustness of AutoTuner parameter selection and found that AutoTuner generated similar parameter estimates from random subsets of samples. We conclude that AutoTuner is a desirable alternative to existing tools, because it is scalable, highly robust, and very fast (～100–1000× speed improvement from other algorithms going from days to minutes). AutoTuner is freely available as an R package through BioConductor.Merdith, A.S., del Real, P.G., Daniel, I., Andreani, M., Wright, N.M., Coltice, N., 2020. Pulsated global hydrogen and methane flux at mid-ocean ridges driven by Pangea breakup. Geochemistry, Geophysics, Geosystems 21, e2019GC008869.: Molecular hydrogen production occurs through the serpentinization of mantle peridotite exhumed at mid‐ocean ridges. Hydrogen is considered essential to sustain microbial life in the subsurface; however, estimates of hydrogen flux through geological time are unknown. Here we present a model of the primary, abiotic production of molecular hydrogen from the serpentinization of oceanic lithosphere using full‐plate tectonic reconstructions for the last 200 Ma. We find significant variability in hydrogen fluxes (1–70 ? 1016 mol/Ma or 0.2–14.1 ? 105 Mt/a), which are a function of the sensitivity of evolving ocean basins to spreading rates and can be correlated with the opening of key ocean basins during the breakup of Pangea. We suggest that the primary driver of this hydrogen flux is the continental reconfiguration during Pangea breakup, as this produces ocean basins more conducive to exhuming and exposing mantle peridotite at slow and ultraslow spreading ridges. Consequently, present‐day flux estimates are ~7 ? 1017 mol/Ma (1.4 ? 106 Mt/a), driven primarily by the slow and ultraslow spreading ridges in the Atlantic, Indian, and Arctic oceans. As methane has also been sampled alongside hydrogen at hydrothermal vents, we estimate the methane flux using methane‐to‐hydrogen ratios from present‐day hydrothermal vent fluids. These ratios suggest that methane flux ranges between 10 and 100% of the total hydrogen flux, although as the release of methane from these systems is still poorly understood, we suggest a lower estimate, equivalent to around 7–12 ? 1016 mol/Ma (1.1–1.9 ? 107 Mt/Ma) of methane.Plain Language Summary: Hydrogen gas is produced when mantle rocks are exposed and react with ocean water at slow spreading mid‐ocean ridges. Only these ridges tend to expose vast expanses of mantle rocks because the temperature is too cool to generate sufficient melt to produce basaltic oceanic crust. Hydrogen produced in this way is consumed by microbial life; however, there is no record of hydrogen through geological time. To overcome this we built a model approximating the volume of serpentinized mantle rocks produced at slow spreading ridges and used geochemical data to constrain the amount of hydrogen that can be produced, as the Fe (II)/[Fe (II) + Fe (III)] of serpentinite is a proxy of hydrogen production from serpentinization. In order to estimate the flux through time, we use global plate models which trace mid‐ocean ridges and the spreading rate. We find that the volume of hydrogen produced is greatest when slow ridges are most abundant and that hydrogen production is concentrated from ridges in the Atlantic, Arctic, and Indian oceans. This is because when a supercontinent breaks up, it produces internal ocean basins that evolve slowly, relative to an ocean basin encompassing the supercontinent (i.e., the Pacific Ocean).Milkov, A.V., Faiz, M., Etiope, G., 2020. Geochemistry of shale gases from around the world: Composition, origins, isotope reversals and rollovers, and implications for the exploration of shale plays. Organic Geochemistry 143, 103997. studied a large dataset of ～2600 shale gas samples from 76 geological formations in 38 sedimentary basins located in eleven countries. Shale gases contain mostly hydrocarbons dominated by methane. Shale gases can have primary microbial, secondary microbial and thermogenic origin. However, gases produced from most commercially successful shale plays (e.g., the Marcellus, Haynesville, Eagle Ford and Barnett in the USA, the Vaca Muerta in Argentina and the Wufeng-Longmaxi in China) are thermogenic. It appears that formations with greater gas endowment such as the Marcellus and the Haynesville contain late-mature thermogenic gas. Shale plays with early-mature thermogenic and secondary microbial gas such as the Antrim (USA) and the New Albany (USA) formations have relatively low endowments of recoverable gas. Shale plays with primary microbial gas are not significant from commercial exploration perspective. Isotope reversals (δ13C of methane?>?δ13C of ethane) are observed in shale plays with mature organic matter (vitrinite reflectance?>?2%) that experienced significant uplift (>2 km). It appears that isotope fractionation during desorption from depressurized late-mature shales leads to isotope reversal in the residual gas produced from shale formations (e.g., the Wufeng-Longmaxi). Significant contribution of adsorbed gas (enriched in 13C-rich C2+ hydrocarbons relative to the co-occurring free gas) in the production from some plays (e.g., the Fayetteville, USA) may result in isotope rollovers.Moniruzzaman, M., Martinez-Gutierrez, C.A., Weinheimer, A.R., Aylward, F.O., 2020. Dynamic genome evolution and complex virocell metabolism of globally-distributed giant viruses. Nature Communications 11, 1710. discovery of eukaryotic giant viruses has transformed our understanding of the limits of viral complexity, but the extent of their encoded metabolic diversity remains unclear. Here we generate 501 metagenome-assembled genomes of Nucleo-Cytoplasmic Large DNA Viruses (NCLDV) from environments around the globe, and analyze their encoded functional capacity. We report a remarkable diversity of metabolic genes in widespread giant viruses, including many involved in nutrient uptake, light harvesting, and nitrogen metabolism. Surprisingly, numerous NCLDV encode the components of glycolysis and the TCA cycle, suggesting that they can re-program fundamental aspects of their host’s central carbon metabolism. Our phylogenetic analysis of NCLDV metabolic genes and their cellular homologs reveals distinct clustering of viral sequences into divergent clades, indicating that?these genes are virus-specific and were acquired in the distant past. Overall our findings reveal that giant viruses encode complex metabolic capabilities with evolutionary histories largely independent of cellular life, strongly implicating them as important drivers of global biogeochemical cycles.Moore, K.A., Altus, S., Tay, J.W., Meehl, J.B., Johnson, E.B., Bortz, D.M., Cameron, J.C., 2020. Mechanical regulation of photosynthesis in cyanobacteria. Nature Microbiology 5, 757-767. organisms regulate their responses to many diverse stimuli in an effort to balance light harvesting with utilizable light energy for carbon fixation and growth (source–sink regulation). This balance is critical to prevent the formation of reactive oxygen species that can lead to cell death. However, investigating the molecular mechanisms that underlie the regulation of photosynthesis in cyanobacteria using ensemble-based measurements remains a challenge due to population heterogeneity. Here, to address this problem, we used long-term quantitative time-lapse fluorescence microscopy, transmission electron microscopy, mathematical modelling and genetic manipulation to visualize and analyse the growth and subcellular dynamics of individual wild-type and mutant cyanobacterial cells over multiple generations. We reveal that mechanical confinement of actively growing Synechococcus sp. PCC 7002 cells leads to the physical disassociation of phycobilisomes and energetic decoupling from the photosynthetic reaction centres. We suggest that the mechanical regulation of photosynthesis is a critical failsafe that prevents cell expansion when light and nutrients are plentiful, but when space is limiting. These results imply that cyanobacteria must convert a fraction of the available light energy into mechanical energy to overcome frictional forces in the environment, providing insight into the regulation of photosynthesis and how microorganisms navigate their physical environment.Mowafy, A.M., 2020. Biological leaching of rare earth elements. World Journal of Microbiology and Biotechnology 36, 61. distinctive physico-chemical features of rare earth elements (REEs) have led to an increase in demand by the global market due to their multiple uses in industrial, medical and agricultural implementations. However, the scarcity of REEs and the harsh eco-unfriendly leaching processes from primary sources beside obliviousness?to?their recycling from?secondary?sources, together with the geopolitical situation, have created the need to develop a more sustainable mining strategy. Therefore, there is a growing interest in bio-hydrometallurgy, which may contribute?to?the?scavenging?of these strategic elements from low-grade resources in an environmentally friendly and economically feasible way as with copper and gold. Several prokaryotes and eukaryotes show the ability to leach REEs, however, the success in employing these microorganisms or their products in this process relays on several biotic and abiotic factors. This review focuses on the differences made by microorganisms in REEs leaching and fundamentally explains microbes-REEs interaction.Müller, J., Joos, F., 2020. Peatland area and carbon over the past 21000 years – a global process based model investigation. Biogeosciences Discussions 2020, 1-33. are an essential part of the terrestrial carbon cycle and the climate system. Understanding their history is key to understand future and past land-atmosphere carbon fluxes. We performed transient simulations over the past 22?000 years with a dynamic global peat and vegetation model forced by Earth System Model climate output, thereby complementing data-based reconstructions for peatlands. Our novel results demonstrate a highly dynamic evolution with concomitant gains and losses of active peatland areas. Modelled gross area changes exceed net changes several fold, while net peat area increases by 60?% over the deglaciation. Peatlands expand to higher northern latitudes in response to warmer and wetter conditions and retreating ice sheets and are partly lost in mid-latitude regions. In the tropics peatlands are partly lost due to flooding of continental shelves and regained by non-linear interactions between temperature, precipitation and CO2. Large north-south shifts of tropical peatlands are driven by shifts in the position of the Inter Tropical Convergence Zone associated with the abrupt climate events of the glacial termination. Time slice simulations for the Last Glacial Maximum (LGM) demonstrate large uncertainties in modelled peatland extent (global range: 1.5 to 3.4?Mkm2) stemming from uncertainties in climate forcing. Net uptake of atmospheric CO2 through peatlands, modelled at 350?GtC since the LGM, includes decay from former peatlands. Carbon uptake would be misestimated, in particular during periods of rapid climate change and subsequent peatland area shifts, when considering only changes in the area of currently active peatlands. Our study highlights the dynamic nature of peatland distribution and calls for an improved understanding of former peatlands to better constrain peat carbon sources and sinks.Mu?oz-Marín, M.C., Gómez-Baena, G., López-Lozano, A., Moreno-Cabezuelo, J.A., Díez, J., García-Fernández, J.M., 2020. Mixotrophy in marine picocyanobacteria: use of organic compounds by Prochlorococcus and Synechococcus. The ISME Journal 14, 1065-1073. picocyanobacteria of the Prochlorococcus and Synechococcus genera have been longtime considered as autotrophic organisms. However, compelling evidence published over the last 15 years shows that these organisms can use different organic compounds containing key elements to survive in oligotrophic oceans, such as N (amino acids, amino sugars), S (dimethylsulfoniopropionate, DMSP), or P (ATP). Furthermore, marine picocyanobacteria can also take up glucose and use it as a source of carbon and energy, despite the fact that this compound is devoid of limiting elements and can also be synthesized by using standard metabolic pathways. This review will outline the main findings suggesting mixotrophy in the marine picocyanobacteria Prochlorococcus and Synechococcus, and its ecological relevance for these important primary producers.Murphy, R.C., 2020. Lipid mass spectrometry: A path traveled for 50 years. Journal of Mass Spectrometry 55, e4492. In the middle of the 1960s, I began graduate school and at the same time started on the path of using mass spectrometry to gain insight into various aspects of lipid biochemistry. This was not a straight path but one that went from organic geochemistry, to lunar sample analysis, to a pursuit of the structure of an elusive and very active, lipid mediator slow reacting substance of anaphylaxis (SRS-A). The discovery of the structure of SRS-A opened important questions about phospholipid biochemistry and the arachidonate cycle in cells. I have written this reflection to highlight the various advances in mass spectrometry that occurred during this time that had a great impact on our ability to study lipid biochemistry. I specifically applied these new advances to studies of leukotriene biosynthesis in vivo, leukotriene metabolism, and arachidonate-containing phospholipids that are essential in providing arachidonic acid for the 5-lipoxygenase pathway. Along the way, imaging mass spectrometry was shown to be a powerful tool to probe lipids as they exist in tissue slices. We found this as just one of the ways to use the emerging technology of lipidomics to study human pathophysiology. Our studies of neutral lipids and oxidized phospholipids were especially challenging due to the total number of molecular species that could be found in cells. Many challenges remain in using mass spectrometry for lipid studies, and a few are presented.Nagornov, K.O., Zennegg, M., Kozhinov, A.N., Tsybin, Y.O., Bleiner, D., 2020. Trace-level persistent organic pollutant analysis with gas-chromatography Orbitrap mass spectrometry—enhanced performance by complementary acquisition and processing of time-domain data. Journal of the American Society for Mass Spectrometry 31, 257-266. range of commercial techniques for high-resolution gas-chromatography–mass spectrometry (GC–MS) has been recently extended with the introduction of GC Orbitrap Fourier transform mass spectrometry (FTMS). We report on progress with quantitation performance in the analysis of persistent organic pollutants (POP), by averaging of time-domain signals (transients), from a number of GC–FTMS experiment replicates. Compared to a standard GC–FTMS measurement (a single GC–FTMS experiment replicate, mass spectra representation in reduced profile mode), for the 10 GC–FTMS technical replicates of ultratrace POP analysis, sensitivity improvement of up to 1 order of magnitude is demonstrated. The accumulation method was implemented with an external high-performance data acquisition system and dedicated data processing software to acquire the time-domain data for each GC–FTMS replicate and to average the acquired GC–FTMS data sets. Concomitantly, the increased flexibility in ion signal detection allowed the attainment of ultrahigh-mass resolution (UHR), approaching R = 700?000 at m/z = 200.Naito, Y.I., Meleg, I.N., Robu, M., Vlaicu, M., Drucker, D.G., Wi?ing, C., Hofreiter, M., Barlow, A., Bocherens, H., 2020. Heavy reliance on plants for Romanian cave bears evidenced by amino acid nitrogen isotope analysis. Scientific Reports 10, 6612. reliance on plants is rare in Carnivora and mostly limited to relatively small species in subtropical settings. The feeding behaviors of extinct cave bears living during Pleistocene cold periods at middle latitudes have been intensely studied using various approaches including isotopic analyses of fossil collagen. In contrast to cave bears from all other regions in Europe, some individuals from Romania show exceptionally high δ15N values that might be indicative of meat consumption. Herbivory on plants with high δ15N values cannot be ruled out based on this method, however. Here we apply an approach using the δ15N values of individual amino acids from collagen that offsets the baseline δ15N variation among environments. The analysis yielded strong signals of reliance on plants for Romanian cave bears based on the δ15N values of glutamate and phenylalanine. These results could suggest that the high variability in bulk collagen δ15N values observed among cave bears in Romania reflects niche partitioning but in a general trophic context of herbivory.Nangle, S.N., Wolfson, M.Y., Hartsough, L., Ma, N.J., Mason, C.E., Merighi, M., Nathan, V., Silver, P.A., Simon, M., Swett, J., Thompson, D.B., Ziesack, M., 2020. The case for biotech on Mars. Nature Biotechnology 38, 401-407. stepwise application of biotechnology will be instrumental to addressing four key challenges of Martian settlement.Nanglu, K., Caron, J.-B., Gaines, R.R., 2020. The Burgess Shale paleocommunity with new insights from Marble Canyon, British Columbia. Paleobiology 46, 58-81. middle (Wuliuan Stage) Cambrian Burgess Shale is famous for its exceptional preservation of diverse and abundant soft-bodied animals through the “thick” Stephen Formation. However, with the exception of the Walcott Quarry (Fossil Ridge) and the stratigraphically older Tulip Beds (Mount Stephen), which are both in Yoho National Park (British Columbia), quantitative assessments of the Burgess Shale have remained limited. Here we first provide a detailed quantitative overview of the diversity and structure of the Marble Canyon Burgess Shale locality based on 16,438 specimens. Located 40 km southeast of the Walcott Quarry in Kootenay National Park (British Columbia), Marble Canyon represents the youngest site of the “thick” Stephen Formation. We then combine paleoecological data sets from Marble Canyon, Walcott Quarry, Tulip Beds, and Raymond Quarry, which lies approximately 20 m directly above the Walcott Quarry, to yield a combined species abundance data set of 77,179 specimens encompassing 234 species-level taxa. Marble Canyon shows significant temporal changes in both taxonomic and ecological groups, suggesting periods of stasis followed by rapid turnover patterns at local and short temporal scales. At wider geographic and temporal scales, the different Burgess Shale sites occupy distinct areas in multivariate space. Overall, this suggests that the Burgess Shale paleocommunity is far patchier than previously thought and varies at both local and regional scales through the “thick” Stephen Formation. This underscores that our understanding of Cambrian diversity and ecological networks, particularly in early animal ecosystems, remains limited and highly dependent on new discoveries.Nardecchia, A., Fabre, C., Cauzid, J., Pelascini, F., Motto-Ros, V., Duponchel, L., 2020. Detection of minor compounds in complex mineral samples from millions of spectra: A new data analysis strategy in LIBS imaging. Analytica Chimica Acta 1114, 66-73., Laser-Induced Breakdown Spectroscopy (LIBS) imaging is in full change. Indeed, always more stable instrumentations are developed, which significantly increases the signal quality and naturally the analytical potential of the technique for the characterization of complex and heterogeneous samples at the micro-scale level. Obviously, other intrinsic features such as a limit of detection in the order of ppm, a high field of view and high acquisition rate make it one of the most complete chemical imaging techniques to date. It is thus possible in these conditions to acquire several million spectra from one single sample in just hours. Managing big data in LIBS imaging is the challenge ahead. In this paper, we put forward a new spectral analysis strategy, called embedded k-means clustering, for simultaneous detection of major and minor compounds and the generation of associated localization maps. A complex rock section with different phases and traces will be explored to demonstrate the value of this approach.Nathan, J.A., 2020. Squalene and cholesterol in the balance at the ER membrane. Proceedings of the National Academy of Sciences 117, 8228-8230. the cholesterol biosynthetic pathway has become a mainstay for the treatment of ischemic heart disease (1). However, the importance of cholesterol metabolism is not just confined to atherosclerosis, as cholesterol is an essential component of membranes, a precursor for other metabolic pathways, and can fuel tumor growth (2). Understanding how the cholesterol synthetic pathway is regulated is therefore of broad biological interest. Cellular cholesterol abundance is tightly regulated through a combination of uptake through low-density lipoprotein receptors and synthesis, with cholesterol sensing occurring at the endoplasmic reticulum (ER) membrane (3, 4). Cholesterol is detected by ER-resident proteins with sterol-sensing domains, which both govern the stability of cholesterol synthetic enzymes and control the release of the SREBP2 transcription factor, regulating the transcription of genes required for cholesterol synthesis and uptake (4). This process is classically exemplified by the sterol-sensitive degradation of HMG-CoA reductase (HMGCR), a rate-limiting step in cholesterol synthesis, and the target of statins (1) (Fig. 1). In PNAS, Yoshioka et al. (5) present findings relating to squalene monooxygenase (SM, also known as squalene epoxidase, SQLE), a further rate-limiting step in the cholesterol synthetic pathway, identifying a previously unappreciated role for squalene in regulating SM stability...Nechaev, V.P., Bechtel, A., Dai, S., Chekryzhov, I.Y., Pavlyutkin, B.I., Vysotskiy, S.V., Ignatiev, A.V., Velivetskaya, T.A., Guo, W., Tarasenko, I.A., Nechaeva, E.V., French, D., Hower, J.C., 2020. Bio-geochemical evolution and critical element mineralization in the Cretaceous-Cenozoic coals from the southern Far East Russia and northeastern China. Applied Geochemistry 117, 104602. total of 23 coal and two carbonaceous shale samples of the Early Cretaceous-Miocene, collected from different basins in the Primorye and Sakhalin regions of Russia, and the Hunchun basin of northeastern China, were used in this study for determination of major oxides (by AES and XRF), trace elements (by ICP-MS), sulfur, carbon, carbon isotopes, and major components of extractable organic matter (wet-chemical and gas-chromatographic analyses). Interpretation of the obtained data was intended to elucidate geodynamic and other geological processes controlling bio-geochemical compositions and critical element mineralization of the studied coals. The data suggest that inorganic matter in the studied coals was derived mainly from the Paleozoic granites and the Cenozoic felsic and intermediate tuffs. The Early Eocene and, in particular, Oligocene epochs represent the two major mineralization events in the regions, resulting in enrichment of Ge, W, Be, Mo, Sb, Sr, Ba, REY (rare earth elements and Y), Th, and U in the coals. The two events were related respectively to the Indo-Eurasian collision followed by plate reorganization in the Pacific and the opening of the Sea of Japan. The geodynamic changes were probably associated with mantle-derived volcanic activity and intensive degassing, which enhanced the capability of surficial and ground waters to leach and redistribute trace metals. Organic matter played a significant role in the system of mineralization, starting from weathering of source rocks and ending at the coal diagenetic stage. Organic acids significantly accelerated leaching and transportation of the metals, while they, together with sulfate-reducing bacteria, kerogen, alcohols?+?ketones, and n-alkanols in particular, played an important role in metal precipitation, mainly through reactions of cation exchange and adsorption.New, J.S., Mathies, R.A., Price, M.C., Cole, M.J., Golozar, M., Spathis, V., Burchell, M.J., Butterworth, A.L., 2020. Characterizing organic particle impacts on inert metal surfaces: Foundations for capturing organic molecules during hypervelocity transits of Enceladus plumes. Meteoritics & Planetary Science 55, 465-479. presence and accessibility of a sub‐ice‐surface saline ocean at Enceladus, together with geothermal activity and a rocky core, make it a compelling location to conduct further, in‐depth, astrobiological investigations to probe for organic molecules indicative of extraterrestrial life. Cryovolcanic plumes in the south polar region of Enceladus enable the use of remote in situ sampling and analysis techniques. However, efficient plume sampling and the transportation of captured organic materials to an organic analyzer present unique challenges for an Enceladus mission. A systematic study, accelerating organic ice‐particle simulants into soft inert metal targets at velocities ranging 0.5–3.0 km s?1, was carried out using a light gas gun to explore the efficacy of a plume capture instrument. Capture efficiency varied for different metal targets as a function of impact velocity and particle size. Importantly, organic chemical compounds remained chemically intact in particles captured at speeds up to ~2 km s?1. Calibration plots relating the velocity, crater, and particle diameter were established to facilitate future ice‐particle impact experiments where the size of individual ice particles is unknown.Newport, S.M., Hennissen, J.A.I., Armstrong, J.P., Taylor, K.G., Newport, L.P., Hough, E., 2020. Can one-run-fixed-Arrhenius kerogen analysis provide comparable organofacies results to detailed palynological analysis? A case study from a prospective Mississippian source rock reservoir (Bowland Shale, UK). Natural Resources Research 29, 2011-2031. analysis, a fundamental component within source rock appraisal based on the study of kerogen within a source rock, is typically produced from microscopy (palynological) and geochemical (kerogen kinetic) data, both of which are costly to acquire. One-Run-Fixed-Arrhenius (ORFA) kerogen kinetic analysis based on Rock–Eval pyrolysis offers a substantially cheaper kinetic dataset. Here, ORFA and palynological analyses are compared in organofacies characterization of a prospective Mississippian source rock reservoir (Bowland Shale, UK). Two-end-member organofacies were determined based on the abundance of the 56 kcal/mol activation energy peak derived from ORFA data: absence (<?5%) indicating ‘organofacies A’ containing the highest proportion of algal material (Type I kerogen); and presence (>?15%) indicating ‘organofacies B’ containing the highest proportion of sporomorphs (Type II kerogen). A mud-dominated slope setting for the rock reservoir was also used to test the accuracy of organofacies analysis in determining depositional environment. Organofacies A found within lithofacies deposited from dilute waning density flows and hemipelagic suspension settling occurred between shelf edge, slope and basin. Organofacies B found within lithofacies deposited from dilute waning density flows, and low-strength cohesive debrites occurred only within the lower slope. This study demonstrates that ORFA kerogen kinetic analysis provides comparable net results to palynological analysis, enabling cheaper and faster organic characterization during initial source rock appraisal. However, caution must be exercised in drawing interpretations as to biological source(s), organic matter mixing and preservation state(s) without additional investigation using data from detailed palynological analysis.Ni, Z., Chen, Y., Zheng, H., Li, N., Li, H., 2020. Stability of copper acetate at high P-T and the role of organic acids and CO2 in metallic mineralization. Scientific Reports 10, 5387. metal deposits were formed by carbonic fluids (rich in CO2) as indicated by fluid inclusions in minerals, but the precise role of CO2 in metal mineralization remains unclear. The main components in fluid inclusions, i.e. H2O and CO2, correspond to the decomposed products of organic acids, which lead us to consider that in the mineralization process the organic acids transport and then discharge metals when they are stable and unstable, respectively. Here we show that the thermal stability of copper acetate solution at 15–350?°C (0.1–830?MPa) provides insight as to the role of organic acids in metal transport. Results show that the copper acetate solution is stable at high P-T conditions under low geothermal gradient of <19?°C/km, with an isochore of P?=?1.89?T?+?128.58, verifying the possibility of copper transportation as acetate solution. Increasing geothermal gradient leads to thermal dissociation of copper acetate in the way of 4Cu(CH3 COO)2 + 2H2O = 4Cu + 2CO2 + 7CH3COOH. The experimental results and inferences in this contribution agree well with the frequently observed fluid inclusions and wall-rock alterations of carbonate, sericite and quartz in hydrothermal deposits, and provide a new dimension in the understanding of the role of CO2 during mineralization.Nielsen, I.?., Vidas Olsen, A., Dicroce-Giacobini, J., Papaleo, E., Andersen, K.K., J??ttel?, M., Maeda, K., Bilgin, M., 2020. Comprehensive evaluation of a quantitative shotgun lipidomics platform for mammalian sample analysis on a high-resolution mass spectrometer. Journal of the American Society for Mass Spectrometry 31, 894-907. lipidomics is a powerful tool that enables simultaneous and fast quantification of diverse lipid classes through mass spectrometry based analyses of directly infused crude lipid extracts. We present here a shotgun lipidomics platform established to quantify 38 lipid classes belonging to four lipid categories present in mammalian samples and show the fine-tuning and comprehensive evaluation of its experimental parameters and performance. We first determined for all the targeted lipid classes the collision energy levels optimal for the recording of their lipid class- and species-specific fragment ions and fine-tuned the energy levels applied in the platform. We then performed a series of titrations to define the boundaries of linear signal response for the targeted lipid classes, and demonstrated that the dynamic quantification range spanned more than 3 orders of magnitude and reached sub picomole levels for 35 lipid classes. The platform identified 273, 261, and 287 lipid species in brain, plasma, and cultured fibroblast samples, respectively, at the respective optimal working sample amounts. The platform properly quantified the majority of these identified lipid species, while lipid species measured to be below the limit of quantification were efficiently removed from the data sets by the use of statistical analyses of data reproducibility or a cutoff threshold. Finally, we demonstrated that a series of parameters of cell culture conditions influence lipidomics outcomes, including confluency, medium supplements, and use of transfection reagents. The present study provides a guideline for setting up and using a simple and efficient platform for quantitatively exploring the mammalian lipidome.Noé, F., Tkatchenko, A., Müller, K.-R., Clementi, C., 2020. Machine learning for molecular simulation. Annual Review of Physical Chemistry 71, 361-390. learning (ML) is transforming all areas of science. The complex and time-consuming calculations in molecular simulations are particularly suitable for an ML revolution and have already been profoundly affected by the application of existing ML methods. Here we review recent ML methods for molecular simulation, with particular focus on (deep) neural networks for the prediction of quantum-mechanical energies and forces, on coarse-grained molecular dynamics, on the extraction of free energy surfaces and kinetics, and on generative network approaches to sample molecular equilibrium structures and compute thermodynamics. To explain these methods and illustrate open methodological problems, we review some important principles of molecular physics and describe how they can be incorporated into ML structures. Finally, we identify and describe a list of open challenges for the interface between ML and molecular simulation.Nozhevnikova, A.N., Russkova, Y.I., Litti, Y.V., Parshina, S.N., Zhuravleva, E.A., Nikitina, A.A., 2020. Syntrophy and interspecies electron transfer in methanogenic microbial communities. Microbiology 89, 129-147. digestion of municipal and other organic waste is a microbial process for conversion of complex organic substances to biogas (a renewable energy source) comprising a mixture of methane and CO2, and a stabilized sludge, which may be used as an organic fertilizer. Diverse groups of the methanogenic microbial community degrade complex organic compounds into simple fermentation products such as hydrogen, formate, acetate, short-chained volatile fatty acids, ethanol, etc. These low-molecular mass products act as the substrates and carriers involved in biogas production by syntrophic bacteria and methanogenic archaea at the methanogenesis stage, the last stage of the anaerobic process. The present review discusses syntrophic interactions between the microorganisms involved in anaerobic degradation of organic substances, as well as two types of interspecies electron transfer (IET): indirect IET (IIET, Indirect Interspecies Electron Transfer) and direct IET (DIET, Direct Interspecies Electron Transfer). DIET-based syntrophic interactions between microorganisms may be stimulated by adding conductive materials into anaerobic digesters, which may have the potential for practical applications.Nye, H., Condron, A., 2020. Assessing the statistical uniqueness of the Younger Dryas: A robust multivariate analysis. Climate of the Past Discussions 2020, 1-21. the last glacial period (c. 120–11 kyr BP), dramatic temperature swings, known as Dansgaard-Oeschger (D-O) events, are clearly manifest in high resolution oxygen isotope records from the Greenland ice sheet. Although variability in the Atlantic Meridional Overturning Circulation (AMOC) is often invoked, a unified explanation for what caused these "sawtooth shaped" climate patterns has yet to be accepted. Of particular interest is the most recent D-O shaped climate pattern that occurred from ～?14,600 to 11,500 years ago – the B?lling/Aller?d (BA) warm interstadial and the subsequent Younger Dryas (YD) cold stadial. Unlike earlier D-O stadials, the YD is frequently considered a unique event, potentially resulting from a rerouting and/or flood of glacial meltwater into the North Atlantic, a meteorite impact, or a volcanic eruption. Yet, these mechanisms are seldom considered as the cause of the earlier stadials. Using a robust multivariate outlier detection scheme – a novel approach for traditional paleoclimate research – we show that the pattern of climate change during the BA/YD is not statistically different from the other D-O events in the Greenland record, and that it should not be considered unique when investigating the drivers of abrupt climate change. Our results thus raise important questions about the ability of glacial meltwater input and other "one off" events to trigger abrupt, centennial-to-millennial length, changes in climate.Nyiri, Z., V?r?s-Palya, D., Novák, M., Eke, Z., 2020. Coupling of large volume injection with flow modulated two-dimensional gas chromatography. Talanta 216, 120984. coupling of large volume injection (LVI) with comprehensive two-dimensional gas chromatography (GC?×?GC) can be a powerful technique in the analysis of trace-level complex samples. The coupling of LVI and GC?×?GC using a cost efficiently operable pneumatic modulator based on capillary flow technology has been examined. The aim was to optimize the LVI parameters in the case of samples with compounds covering a wide boiling range. For the optimization of LVI 25 microliters of a solution containing 27 target compounds modelling the composition and the boiling range of diesel oils was used. The injection parameters were evaluated for peak shapes, reproducibility and peak volumes relative to peak volumes obtained using cold splitless injection. For all GC?×?GC experiments a non-polar first column (Rxi-5ms) and a polar second column (HP-INNOWax) were applied. Through extensive method optimization solvent vent proved to be unsuitable an technique for the injection of compounds covering a wide boiling range: at lower vent times peaks split, while higher vent times caused severe losses of highly volatile compounds. Therefore, a split-splitless LVI method was optimized. Injection speed, split vent time, splitless vent time and vent flow during split vent have been optimized. The developed method is suitable for the coupling of LVI with flow modulated GC?×?GC. Using the optimized split-splitless LVI parameters no peak distortion of the target compounds was observed. The relative peak volumes were between 60–120% for all compounds (80–120% for 13 compounds).O'Keefe, J.M.K., Pound, M.J., Riding, J.B., Vane, C.H., 2020. Cellular preservation and maceral development in lignite and wood from the Brassington Formation (Miocene), Derbyshire, UK. International Journal of Coal Geology 222, 103452. wood is well known from the uppermost part of the Brassington Formation of Miocene age from two localities in Derbyshire, central England, UK, but its preservation has not been previously studied. Likewise, lignite is also present but has not been studied hitherto. This study examines preservation of selected wood samples using a combination of organic petrography and organic geochemistry. The best conserved exposure of the Kenslow Member of the Brassington Formation, representing the majority of the lower Kenslow Member, occurs at Bees Nest Pit. Disseminated woods occur throughout the Kenslow Member, with the greatest concentrations, and largest specimens, occurring around a meter below a thin lignite at Bees Nest Pit. The lignite is composed primarily of wood and charcoal, as well as organic-rich clay and leaves. Wood in the lignite and in the disseminated wood samples appear unaltered or charred in hand sample. Larger pieces typically have numerous cracks and pockets in the surface, highly suggestive of desiccation and white-rot prior to burial, but appear to be solid mummified wood overall. Drying in acetone and epoxy impregnation permitted the wood and lignite to be examined using reflected light microscopy, while air-dried wood samples were coated with gold?palladium and examined using SEM and prepared for organic geochemistry. All wood samples examined herein appear to be softwoods. Members of the “charred” group have high-reflecting exteriors and low-reflecting interiors in reflected white light illumination. Members of the “unaltered” group of tissues are consistently low-reflecting unaltered to slightly gelified textinite and ulminite A which display different reflectivity in transverse and radial sections. Random reflectance places the unaltered wood in the upper range of peat or lowest range of lignite B. Low-reflecting cells are primarily fiber cells and are strongly fluorescent. In most cases the three-ply fiber cell wall has begun to delaminate, a key feature of white-rot decomposition of the wood. Rays appear largely unaltered, and bordered pits show no evidence of fungal hyphae. Annual rings and vessels, by contrast, have undergone significant humification and have the appearance of ulminite and textinite, respectively. Near the wood margins, extensive pockets of rot show strong gelification, with the result that the cellular framework is gelified and brightly reflecting with isolated fibers present which still fluoresce. Huminite reflectance suggests that during very early stage lignification, reflectance varies depending upon cellular orientation, with cells in transverse section being more highly reflective than those in radial section. Organic geochemistry indicates all the fossil woods are chemically altered relative to modern counterparts. The elemental ratios suggest these sit between modern wood and brown coal. The changes are probably due to loss of polysaccharide as compared to lignin structures. The spread in O/C and H/C is probably due to variable microbial alteration (e.g. white, soft or brown rot fungal decay), as also indicated by the organic petrography. This type of wood preservation is consistent with early coalification in aerial settings, and consistent with fungi recovered during palynological studies which are indicative of softwoods decaying in wet forest settings.Ocubalidet, S., Carvajal-Ortiz, H., Gentzis, T., 2020. Post-well stimulation allocation of commingled production using geochemical fingerprinting techniques in unconventional reservoirs: A review of methods, and a case study of the Montney Formation, Western Canadian Sedimentary Basin. International Journal of Coal Geology 224, 103476. methods used in allocating commingled production in conventional reservoirs are similar to those that are effective in performing the same task on unconventional reservoirs. However, the protocols to follow can vary a great deal. The presence of distinct endmembers in the former allows the use of the method of production allocation using peak height ratios and mixing curves and using linear regression of peak heights. Due to the possible contribution from multiple intervals in the same formation or even from different formations as in the case of fracture stimulated unconventional reservoirs, the combined application of methods that compare the quantities and carbon stable isotopes of selected compounds (such as saturate and aromatic hydrocarbons) and other parameters (such as API gravity) was employed. This was done based on a series of samples presumed to represent the endmembers via their HRGC and GCMS oil fingerprint, followed by the determination of the contribution from each sample by using an algebraic solution of simultaneous linear equations. A review of the two methods is provided.The aforementioned method for unconventional resources is demonstrated in a case study of production allocation that was performed on three produced oils sampled at different times from three separate wells, “A” “C”, and “D”, located in the Western Canadian Sedimentary Basin. A total of 25 core extract samples representing two producing zones (end members) of the Montney Formation (i.e., the Middle and the Lower Montney) from well “A” and “B” were used. Results of GC and GCMS analyses of the samples were evaluated; rigorous filters, cluster analysis (dendrograms), and Principal Component Analysis (PCA) were applied to identify any clustering or variation between the samples representing possible contributor layers and the commingled oil. Then, using proprietary software and statistical techniques, the fingerprint of selected compounds was qualitatively compared and their quantity in each of the rock extracts and the produced oils was determined in order to allocate the contribution from the two end members that each extract belongs to.Results from the method for unconventional resources were compared to other data (such as GC trace patterns) for consistency. The case study demonstrates that a combined approach that accounts for the entire fingerprint (i.e., GC and molecular markers (including biomarker and non-biomarker parameters)), produces the best results and minimizes uncertainty.?dalen, M., Nycander, J., Ridgwell, A., Oliver, K.I.C., Peterson, C.D., Nilsson, J., 2020. Variable C∕P composition of organic production and its effect on ocean carbon storage in glacial-like model simulations. Biogeosciences 17, 2219-2244. the four most recent glacial maxima, atmospheric CO2 has been lowered by about 90–100?ppm with respect to interglacial concentrations. It is likely that most of the atmospheric CO2 deficit was stored in the ocean. Changes in the biological pump, which are related to the efficiency of the biological carbon uptake in the surface ocean and/or of the export of organic carbon to the deep ocean, have been proposed as a key mechanism for the increased glacial oceanic CO2 storage. The biological pump is strongly constrained by the amount of available surface nutrients. In models, it is generally assumed that the ratio between elemental nutrients, such as phosphorus, and carbon (C∕P ratio) in organic material is fixed according to the classical Redfield ratio. The constant Redfield ratio appears to approximately hold when averaged over basin scales, but observations document highly variable C∕P ratios on regional scales and between species. If the C∕P ratio increases when phosphate availability is scarce, as observations suggest, this has the potential to further increase glacial oceanic CO2 storage in response to changes in surface nutrient distributions. In the present study, we perform a sensitivity study to test how a phosphate-concentration-dependent C∕P ratio influences the oceanic CO2 storage in an Earth system model of intermediate complexity (cGENIE). We carry out simulations of glacial-like changes in albedo, radiative forcing, wind-forced circulation, remineralization depth of organic matter, and mineral dust deposition. Specifically, we compare model versions with the classical constant Redfield ratio and an observationally motivated variable C∕P ratio, in which the carbon uptake increases with decreasing phosphate concentration. While a flexible C∕P ratio does not impact the model's ability to simulate benthic δ13C patterns seen in observational data, our results indicate that, in production of organic matter, flexible C∕P can further increase the oceanic storage of CO2 in glacial model simulations. Past and future changes in the C∕P ratio thus have implications for correctly projecting changes in oceanic carbon storage in glacial-to-interglacial transitions as well as in the present context of increasing atmospheric CO2 concentrations.Oh, Y., Zhuang, Q., Liu, L., Welp, L.R., Lau, M.C.Y., Onstott, T.C., Medvigy, D., Bruhwiler, L., Dlugokencky, E.J., Hugelius, G., D’Imperio, L., Elberling, B., 2020. Reduced net methane emissions due to microbial methane oxidation in a warmer Arctic. Nature Climate Change 10, 317-321. emissions from organic-rich soils in the Arctic have been extensively studied due to their potential to increase the atmospheric methane burden as permafrost thaws. However, this methane source might have been overestimated without considering high-affinity methanotrophs (HAMs; methane-oxidizing bacteria) recently identified in Arctic mineral soils. Herein we find that integrating the dynamics of HAMs and methanogens into a biogeochemistry model that includes permafrost soil organic carbon dynamics leads to the upland methane sink doubling (~5.5?Tg?CH4?yr?1) north of 50?°N in simulations from 2000–2016. The increase is equivalent to at least half of the difference in net methane emissions estimated between process-based models and observation-based inversions, and the revised estimates better match site-level and regional observations. The new model projects doubled wetland methane emissions between 2017–2100 due to more accessible permafrost carbon. However, most of the increase in wetland emissions is offset by a concordant increase in the upland sink, leading to only an 18% increase in net methane emission (from 29 to 35?Tg?CH4?yr?1). The projected net methane emissions may decrease further due to different physiological responses between HAMs and methanogens in response to increasing temperature.Pan, H., Li, A., Cui, Z., Ding, D., Qu, K., Zheng, Y., Lu, L., Jiang, T., Jiang, T., 2020. A comparative study of phytoplankton community structure and biomass determined by HPLC-CHEMTAX and microscopic methods during summer and autumn in the central Bohai Sea, China. Marine Pollution Bulletin 155, 111172. the largest inland sea of China, the Bohai Sea has confronted significant environmental changes in recent decades, and a shift of phytoplankton community from diatoms to dinoflagellates was observed by microscopic method in previous studies. However, the counting of some small-sized non-diatoms (e.g., flagellates and cyanobacteria) have long been neglected due to the limitation of this method. In this study, we measured the phytoplankton community structure and abundance in the central Bohai Sea in summer and autumn of 2015 by employing both microscopic method and high-performance liquid chromatography (HPLC) pigments – CHEMTAX analysis. The results of microscopic counting showed that the phytoplankton community was characterized by diatoms, dinoflagellates, and chrysophytes, which contained a total of 107 species. Dinoflagellates and diatoms co-dominated in summer while the latter became the dominant group in autumn. Compared with microscopic counting, CHEMTAX analysis allowed identification of a larger number of phytoplankton groups (including 8 phyla). The results of CHEMTAX analysis showed that besides diatoms and dinoflagellates, the small-sized non-diatoms (i.e., flagellates and cyanobacteria) also played an important role. Diatoms and cyanobacteria dominated the total Chl a (contributing 32.5% and 17.1%, respectively), followed by cryptophytes, dinoflagellates, and prasinophytes in the summer. A short-term summer to autumn variability of phytoplankton abundance and community was observed. Temperature and nutrient availability affected the succession of the phytoplankton community from diatoms and non-diatoms co-dominance in the summer to absolute diatoms dominance in the autumn. A direct comparison of algal cell abundance and CHEMTAX biomass showed that a significant positive correlation was observed only for dinoflagellates (P?<?0.01) in the autumn. Our work provides some basic information on the dynamics of small-sized flagellates and cyanobacteria in this area, and also suggests that a combination of both the methods is needed in future investigations to better understand the current status as well as the future changes of phytoplankton community.Pan, J., Zhou, Z., Béjà, O., Cai, M., Yang, Y., Liu, Y., Gu, J.-D., Li, M., 2020. Genomic and transcriptomic evidence of light-sensing, porphyrin biosynthesis, Calvin-Benson-Bassham cycle, and urea production in Bathyarchaeota. Microbiome 8, 43.: Bathyarchaeota, a newly proposed archaeal phylum, is considered as an important driver of the global carbon cycle. However, due to the great diversity of them, there is limited genomic information that accurately encompasses the metabolic potential of the entire archaeal phylum.Results: In the current study, nine metagenome-assembled genomes of Bathyarchaeota from four subgroups were constructed from mangrove sediments, and metatranscriptomes were obtained for evaluating their in situ transcriptional activities. Comparative analyses with reference genomes and the transcripts of functional genes posit an expanded role for Bathyarchaeota in phototrophy, autotrophy, and nitrogen and sulfur cycles, respectively. Notably, the presence of genes for rhodopsins, cobalamin biosynthesis, and the oxygen-dependent metabolic pathways in some Bathyarchaeota subgroup 6 genomes suggest a light-sensing and microoxic lifestyle within this subgroup.Conclusions: The results of this study expand our knowledge of metabolic abilities and diverse lifestyles of Bathyarchaeota, highlighting the crucial role of Bathyarchaeota in geochemical cycle.Pan, L., Oldenburg, C.M., 2020. Mechanistic modeling of CO2 well leakage in a generic abandoned well through a bridge plug cement-casing gap. International Journal of Greenhouse Gas Control 97, 103025. known and unmapped plugged and abandoned wells are potential leakage pathways for CO2 from geologic carbon sequestration (GCS) sites. Although many abandoned wells have cement bridge plugs installed to prevent leakage, the seal between the cement and the inner casing wall is subject to failure. In this study, we carried out detailed T2Well simulations of cases of sudden non-Darcy flow of CO2 and brine leakage up the gap between a cement plug and the inner steel casing wall that becomes a fully connected flow path during the post-injection period. The goal of our study was two-fold: (1) to understand the dynamics, rates, and the characteristic temporal signals associated with the onset of leakage through various gap-aperture sizes, and (2) to suggest potential monitoring strategies based on the findings. Simulation results show that the leakage of CO2 and brine upward is transient with interesting phase interference behavior. Time-dependent oscillatory flows with varying pressure, temperature, and flow rates of CO2 and brine show strong dependence on gap aperture. Phase-change and decompression lead to very low temperatures at the top of the well for gap apertures larger than 4?mm suggesting that remote thermal monitoring at the ground surface may be an effective way of monitoring even if well locations are not known a priori. Pressure in the well is also indicative of CO2 leakage. The temporal patterns of changing temperature and pressure may be useful diagnostic signals for leakage detection. Finally, these transient leakage signals may provide information on the cause of leakage and/or characteristics of the flow path that could inform effective remediation design and execution approaches.Pang, Y., Guo, X., Shi, B., Zhang, X., Cai, L., Han, Z., Chang, X., Xiao, G., 2020. Hydrocarbon generation evaluation, burial history, and thermal maturity of the Lower Triassic–Silurian organic-rich sedimentary rocks in the Central Uplift of the South Yellow Sea Basin, East Asia. Energy & Fuels 34, 4565-4578. study focuses on the organic-rich rocks in the Central Uplift of the South Yellow Sea Basin using the CSDP-2 borehole, which was drilled through the integrated Lower Triassic–Silurian sediments and yielded approximately 2736 m of cores. Geochemical analyses of core samples, including Rock-Eval pyrolysis, elemental analysis, maceral analysis, and gas chromatography–mass spectrometry, revealed multiple sets of effective source rocks developed from the Lower Triassic Qinglong Formation to the Lower Silurian Gaojiabian Formation. The organic matter is dominated by types II–III kerogen, most of which are mature to post-mature. Comprehensive geochemical analysis shows that Permian and Lower Carboniferous mudstones are the most important source rocks and have strong hydrocarbon generation capacity. Most of the source rocks are dominated by planktonic/bacterial sources and deposited mainly in a low-salinity marine environment, and influenced by the input of terrigenous detrital materials. Basin modeling results show that most of the Paleozoic–Mesozoic source rocks in the Central Uplift generally entered the oil-generation window during the Triassic to Late Jurassic. The timing of hydrocarbon generation and expulsion was simultaneous or earlier than the collisional orogenic movement between the Sino-Korean Platform and the Lower Yangtze Craton, which may have some destructive impact on the oil and gas preservation. Therefore, it is preservation condition rather than source rocks that may be one of the most important elements for hydrocarbon accumulation in the Central Uplift of the SYSB.Parai, R., 2020. Nitrogen variations in the mantle might have survived since Earth’s formation. Nature 580, 324-325. method for identifying atmospheric contamination of volcanic-gas samples reveals variations in the isotopic composition of nitrogen in the mantle, and provides a clearer view of the origins of this element in Earth’s interior. Earth’s nitrogen-rich atmosphere contributes to the pleasant surface environment in which we live and breathe — but makes it very difficult to determine the nitrogen isotope composition of anything else. Pervasive atmospheric contamination of samples derived from Earth’s mantle poses a formidable challenge to anyone investigating the origins and transport of volatile species, such as nitrogen and the noble gases, in the deep Earth. In a paper in Nature, Labidi et al.1 report that they have used a ‘clumped isotope’ method to identify uncontaminated mantle nitrogen in volcanic-gas effusions and gases trapped in volcanic-rock samples. The relative abundances of isotopes in uncontaminated nitrogen vary among samples from different locations. The authors argue that these differences originate from Earth’s formation and have survived approximately 4.5 billion years of mixing associated with mantle convection.There are two stable nitrogen isotopes, 14N and 15N, and their relative abundances are expressed as δ15N values — the parts per thousand deviation of the 15N/14N ratio from a standard value. The nitrogen isotopic compositions of mantle-derived samples can provide insight into a wide range of topics, from the mix of planetary building blocks that brought volatile species to Earth during its formation2, to the transport of atmospheric nitrogen into the mantle through the sinking of tectonic plates over time3.Apart from the proportions of 14N and 15N in a sample, the way that isotopes are distributed between molecules also provides information. An isotopologue is a molecule that has a specific combination of isotopes of its constituent elements. For example, diatomic nitrogen molecules (N2, which constitute about 78% of the atmosphere by volume) can incorporate either 14N or 15N, yielding three possible isotopologues: 14N14N, 14N15N and 15N15N. Because the vast majority of nitrogen is 14N, the most common isotopologue is 14N14N. Substitution of a single 15N for 14N is rare; a doubly substituted isotopologue (15N15N) is rarer still. A random distribution of 14N and 15N between N2 molecules produces a specific mixture of the three isotopologues. Any measured deviation from the expected proportion of 15N15N is described as a clumped-isotope anomaly.Earth’s atmospheric N2 exhibits a well-resolved clumped-isotope anomaly4, and Labidi et al. used this signature to identify atmospheric contamination of volcanic gases. The authors established that mantle N2 has no clumped-isotope anomaly by analysing nitrogen released from unusually gas-rich samples of mid-ocean ridge basalt, confirming the expectation that magmatic gases have a random distribution of isotopes among N2 isotopologues. With this information in hand, the authors examined nitrogen isotope compositions in hydrothermal gases sampled from Yellowstone National Park in the United States, Iceland and other volcanic localities. They identified the nitrogen isotope compositions of the mantle sampled at locations at which trends showing varying degrees of atmospheric contamination were evident.In previous studies3,5 of nitrogen in mantle-derived gases, systematic variations among measured nitrogen and noble-gas compositions were sought to identify atmospheric contamination, but contradictory signatures were sometimes observed — some metrics indicated that there was contamination, whereas others suggested there was none. Labidi and colleagues show that data that might have been interpreted as mantle compositions on the basis of relationships between nitrogen and noble gases are, in fact, affected by atmospheric N2 contamination.Their study also indicates that δ15N variations are produced in atmospheric N2 as it circulates through hydrothermal systems. However, the processes that generate such changes in the bulk proportions of 14N and 15N do not redistribute isotopes among isotopologues, so that the atmospheric clumped-isotope anomaly is preserved — which means that any contamination remains identifiable. There is no place for atmospheric N2 to hide if one is looking through a clumped-isotope lens.An important feature of the authors’ analytical approach is that it is not necessary to measure pure, uncontaminated magmatic gas to estimate the mantle composition. Even if multiple atmospheric contaminants are present, evidence of mixing trends in the data can be used to identify the mantle δ15N value of magmatic gas, which has no clumped-isotope anomaly. Labidi et al. report a mantle δ15N value for the potentially deep-seated6,7 Yellowstone mantle plume that is distinct from those determined for mid-ocean ridge basalts. With uncertainties regarding atmospheric contamination eliminated, nitrogen isotope variations in the mantle can be interpreted in the context of Earth’s formation, differentiation into distinct layers, and the long-term coevolution of the deep Earth and surface owing to plate tectonics (Fig. 1).To test whether nitrogen exchange between the surface and mantle over time explains their results, Labidi and co-workers developed a mathematical model of nitrogen evolution in the mantle. Intriguingly, the results suggest that there has been a net loss of nitrogen from the convective mantle over most of Earth’s history, and little incorporation of surface nitrogen into the mantle. This contrasts with previously reported evidence of substantial incorporation of atmospheric xenon into the mantle8,9. Given the limited role of surface nitrogen in the mantle, the authors argue that the observed nitrogen isotope variations are a remnant from Earth’s formation and early differentiation, when volatile species were delivered to the growing Earth as it separated into the core, mantle, crust and atmosphere.Evidence that early-formed mantle heterogeneities survive in the modern mantle has come from studies of signatures formed by rapidly decaying radioactive isotopes that decayed within the first 100 million years of Earth’s history8,10. It will be challenging to confirm that the nitrogen isotope variations identified by Labidi et al. arose early in Earth’s evolution, given that neither of the element’s two isotopes is produced by radioactive decay and that surface signatures might have a confounding role, however limited. Determination of δ15N values at other plume localities, including regions thought to be influenced by the recycling of surface materials11, would provide an interesting test of the authors’ primordial hypothesis. The application of clumped-isotope analysis reported by Labidi et al. provides an exciting method for such future studies — we now have an improved tool with which to view the origins and evolution of volatile species in the mantle.References1. Labidi, J. et al. Nature 580, 367–371 (2020).2. Füri, E. & Marty, B. Nature Geosci. 8, 515–522 (2015).3. Dauphas, N. & Marty, B. Science 286, 2488–2490 (1999).4. Yeung, L. Y. et al. Sci. Adv. 3, eaao6741 (2017).5. Fischer, T. P. et al. Science 297, 1154–1157 (2002).6. Burdick, S. et al. Seismol. Res. Lett. 80, 638–645 (2009).7. Nelson, P. L. & Grand, S. P. Nature Geosci. 11, 280–284 (2018).8. Mukhopadhyay, S. Nature 486, 101–124 (2012).9. Holland, G. & Ballentine, C. J. Nature 441, 186–191 (2006).10. Rizo, H. et al. Science 352, 809–812 (2016).11. Hofmann, A. W. Nature 385, 219–229 (1997).Park, S., Cho, Y.-J., Jung, D.-y., Jo, K.-n., Lee, E.-J., Lee, J.-S., 2020. Microbial diversity in moonmilk of Baeg-nyong Cave, Korean CZO. Frontiers in Microbiology 11, 613. doi: 10.3389/fmicb.2020.00613. Baeg-nyong cave is a limestone cave which has been nominated as the first critical zone observatory (CZO) in South Korea. Moonmilk is a well-known speleothem composed of various carbonate minerals. To characterize moonmilk from the Baeg-nyong cave, we performed mineralogical analyses and applied high-throughput 16S rRNA gene sequencing to analyze the microbial communities, including bacteria and fungi, of dry and wet moonmilk samples. The results showed that the dry and wet moonmilk samples had different and atypical crystal structures, although they were predominantly composed of CaCO3. Furthermore, metagenomic data revealed that the dry and wet moonmilk samples collected from an oligotrophic environment had completely different bacterial communities when compared to the outside soil, and there was a difference in bacterial communities even between dry and wet moonmilk specimens. Fungal communities, however, did not differ significantly between dry and wet moonmilk samples. This study is the first metagenomic analysis of two different types of moonmilk with different physical properties and the first report on the microbial diversity of moonmilk from a cave in the first CZO in South Korea.Pearson, C., Salzer, M., Wacker, L., Brewer, P., Sookdeo, A., Kuniholm, P., 2020. Securing timelines in the ancient Mediterranean using multiproxy annual tree-ring data. Proceedings of the National Academy of Sciences 117, 8410-8415.: This study demonstrates how different lines of evidence from tree rings in widely spread growth locations can combine to fix an approximately dated tree-ring record from the East Mediterranean Bronze–Iron Age to an exact calendar-dated range. This tree-ring record is of high importance for regional chronology and spans the time period in which the major volcanic eruption of Thera (Santorini) occurred. Exact dating of this eruption is important because it provides a prominent marker horizon through which ancient timelines of the East Mediterranean, Egypt, and the Levant can be synchronized. Chemical analysis of the dated tree-ring sequence identifies a chemical change in their growth environment around 1560 BC, which while requiring further substantiation, may be evidence of the Thera eruption.Abstract: Calendar-dated tree-ring sequences offer an unparalleled resource for high-resolution paleoenvironmental reconstruction. Where such records exist for a few limited geographic regions over the last 8,000 to 12,000 years, they have proved invaluable for creating precise and accurate timelines for past human and environmental interactions. To expand such records across new geographic territory or extend data for certain regions further backward in time, new applications must be developed to secure “floating” (not yet absolutely dated) tree-ring sequences, which cannot be assigned single-calendar year dates by standard dendrochronological techniques. This study develops two approaches to this problem for a critical floating tree-ring chronology from the East Mediterranean Bronze–Iron Age. The chronology is more closely fixed in time using annually resolved patterns of 14C, modulated by cosmic radiation, between 1700 and 1480 BC. This placement is then tested using an anticorrelation between calendar-dated tree-ring growth responses to climatically effective volcanism in North American bristlecone pine and the Mediterranean trees. Examination of the newly dated Mediterranean tree-ring sequence between 1630 and 1500 BC using X-ray fluorescence revealed an unusual calcium anomaly around 1560 BC. While requiring further replication and analysis, this anomaly merits exploration as a potential marker for the eruption of Thera.Pennetta, A., Fico, D., Eramo, G., Muntoni, I.M., De Benedetto, G.E., 2020. Extending the inter-Adriatic trade of bitumen beyond the fifth millennium BCE. Organic Geochemistry 142, 104013. dei Cervi (Apulia, Southern Italy) is the most important European figurative art site for its Neolithic red and brown paintings found in the various galleries of the cave. It was frequented with particular intensity between an advanced phase of the Early Neolithic (first half of the sixth millennium BCE) and continued up to the end of the Bronze Age (last centuries of the second millennium BCE). Among the more than thirty thousand finds, some ceramic shards had black residues on them. These residues were sampled so that molecular and isotopic investigations could be carried out. GC–MS-MS and EA–IRMS after fractionation of the samples allowed us to identify bitumen on some archaeological potsherd remains and to identify its geographic source by comparison with geological samples from Majella and Selenic?, two deposits located respectively in Italy and Albania and known to have been exploited since Neolithic times. All the bitumens from Porto Badisco correlate with each other and with the Selenic? geological samples. Isotopic fingerprints strongly support the biomolecular evidence and confirm the Albanian origin of the archaeological bitumen. The data presented herein provide the first evidence of export and trade of raw bitumen across the Adriatic Sea from Selenic? to Apulia during the Neolithic age thus bringing back to the fifth millennium BCE the transport of bitumen across the Adriatic Sea in the central Mediterranean area.Pérez-Cova, M., Tauler, R., Jaumot, J., 2020. Chemometrics in comprehensive two-dimensional liquid chromatography: A study of the data structure and its multilinear behavior. Chemometrics and Intelligent Laboratory Systems 201, 104009. multidimensional chromatographic techniques, such as GC×GC coupled to FID or MS and LC×LC coupled to UV or MS, have gained popularity in recent years. From the analytical perspective, these techniques allow obtaining higher peak capacities and resolution power, as well as adding selectivity from the second orthogonal dimension. From the chemometric point of view, these multidimensional techniques generate highly complex datasets, which present several challenges for their analysis. On the one hand, the selection of the appropriate chemometric data analysis tool requires the understanding of the underlying data structure and its multilinear behavior. On the other hand, peak resolution in complex samples is still a challenge, because of their possible overlapping in one or two chromatographic dimensions despite the increased resolution power.In this work, a comprehensive two-dimensional liquid chromatography method hyphenated simultaneously to PDA and MS detectors was employed for the analysis of a mixture of 31 pharmaceutical compounds. Chemometric evaluation of the obtained two-dimensional chromatograms focuses on two different goals. First, the assessment of the multilinear behavior of the high-dimensional data for each of the two detection modes (LC×LC-UV and LC×LC-MS) and, also, for the multiset data obtained by fusion of the data coming from both detectors. In addition, the chemometric resolution of peaks of overlapping compounds was evaluated using the multivariate curve resolution alternating least squares (MCR-ALS) method. Finally, the advantages of data fusion from UV and MS detectors were discussed, such as the increased ability for compound identification.Perez, F., Devegowda, D., 2020. A molecular dynamics study of soaking during enhanced oil recovery in shale organic pores. SPE Journal 25, 832-841. this work we use molecular dynamics simulations to investigate the interactions during soaking time between an organic solvent (pure ethane) initially in a microfracture and a mixture of hydrocarbons representative of a volatile oil, and other reservoir fluids such as carbon dioxide and water, originally saturating an organic pore network with a predominant pore size of 2.5 nm. We present evidence of the in-situ fractionation in liquid-rich shales and its implications in enhanced oil recovery (EOR) projects. We also discuss the behavior of the larger and heavier molecules in the fluid mixture while the solvent interacts with them. Notably, prior to solvent invasion of the pores and further mixing with the reservoir fluids, the heavier hydrocarbons in the mixture are initially adsorbed onto the pore surface and pore throats surface, partially clogging them. We show that the porous structure of kerogen and the presence of adsorbed molecules of asphaltenes and resins in the pore throats act as a molecular sieve and may be one of the reasons for the fractionation of the reservoir fluids. The differing ability of the solvent to desorb and mix with different hydrocarbon species is another reason for the fractionation occurring during soaking. Our simulations show that the production of reservoir fluids occurs due to a countercurrent diffusive flow from the organic pore network to the microfracture driven by the concentration gradient between the two regions.Perry, W.J., Patterson, N.H., Prentice, B.M., Neumann, E.K., Caprioli, R.M., Spraggins, J.M., 2020. Uncovering matrix effects on lipid analyses in MALDI imaging mass spectrometry experiments. Journal of Mass Spectrometry 55, e4491. specific matrix used in matrix‐assisted laser desorption/ionization imaging mass spectrometry (MALDI IMS) can have an effect on the molecules ionized from a tissue sample. The sensitivity for distinct classes of biomolecules can vary when employing different MALDI matrices. Here, we compare the intensities of various lipid subclasses measured by Fourier transform ion cyclotron resonance (FT‐ICR) IMS of murine liver tissue when using 9‐aminoacridine (9AA), 5‐chloro‐2‐mercaptobenzothiazole (CMBT), 1,5‐diaminonaphthalene (DAN), 2,5‐Dihydroxyacetophenone (DHA), and 2,5‐dihydroxybenzoic acid (DHB). Principal component analysis and receiver operating characteristic curve analysis revealed significant matrix effects on the relative signal intensities observed for different lipid subclasses and adducts. Comparison of spectral profiles and quantitative assessment of the number and intensity of species from each lipid subclass showed that each matrix produces unique lipid signals. In positive ion mode, matrix application methods played a role in the MALDI analysis for different cationic species. Comparisons of different methods for the application of DHA showed a significant increase in the intensity of sodiated and potassiated analytes when using an aerosol sprayer. In negative ion mode, lipid profiles generated using DAN were significantly different than all other matrices tested. This difference was found to be driven by modification of phosphatidylcholines during ionization that enables them to be detected in negative ion mode. These modified phosphatidylcholines are isomeric with common phosphatidylethanolamines confounding MALDI IMS analysis when using DAN. These results show an experimental basis of MALDI analyses when analyzing lipids from tissue and allow for more informed selection of MALDI matrices when performing lipid IMS experiments.Phillips, J.C., 2020. Self-organized networks: Darwinian evolution of dynein rings, stalks, and stalk heads. Proceedings of the National Academy of Sciences 117, 7799-7802.: Proteins are the prime example of self-organized networks, as they have benefited from extensive natural (Darwinian) selection. Here, we quantify the dynamical shapes of dynein as they have evolved through interactions with water films. The interactions are long-range and are easily identified, and their improvement by evolution varies with the functions of parts of this molecular motor. It appears that evolution has brought human dynein close to a dynamical critical point, indicative of intelligent design.Abstract: Cytoskeletons are self-organized networks based on polymerized proteins: actin, tubulin, and driven by motor proteins, such as myosin, kinesin, and dynein. Their positive Darwinian evolution enables them to approach optimized functionality (self-organized criticality). Dynein has three distinct titled subunits, but how these units connect to function as a molecular motor is mysterious. Dynein binds to tubulin through two coiled coil stalks and a stalk head. The energy used to alter the head binding and propel cargo along tubulin is supplied by ATP at a ring 1,500 amino acids away. Here, we show how many details of this extremely distant interaction are explained by water waves quantified by thermodynamic scaling. Water waves have shaped all proteins throughout positive Darwinian evolution, and many aspects of long-range water–protein interactions are universal (described by self-organized criticality). Dynein water waves resembling tsunami produce nearly optimal energy transport over 1,500 amino acids along dynein’s one-dimensional peptide backbone. More specifically, this paper identifies many similarities in the function and evolution of dynein compared to other cytoskeleton proteins such as actin, myosin, and tubulin.Pickens, C.J., Haidar Ahmad, I.A., Makarov, A.A., Bennett, R., Mann, B.F., Regalado, E.L., 2020. Comprehensive online multicolumn two-dimensional liquid chromatography-diode array detection-mass spectrometry workflow as a framework for chromatographic screening and analysis of new drug substances. Analytical and Bioanalytical Chemistry 412, 2655-2663. analysis of complex mixtures of closely related species is quickly becoming a bottleneck in the development of new drug substances, reflecting the ever-increasing complexity of both fundamental biology and the therapeutics used to treat disease. Two-dimensional liquid chromatography (2D-LC) is emerging as a powerful tool to achieve substantial improvements in peak capacity and selectivity. However, 2D-LC suffers from several limitations, including the lack of automated multicolumn setups capable of combining multiple columns in both dimensions. Herein, we report an investigation into the development and implementation of a customized online comprehensive multicolumn 2D-LC-DAD-MS setup for screening and method development purposes, as well as analysis of multicomponent biopharmaceutical mixtures. In this study, excellent chromatographic performance in terms of selectivity, peak shape, and reproducibility were achieved by combining reversed-phase (RP), strong cation exchange (SCX), strong anion exchange (SAX), and size exclusion chromatography (SEC) using sub-2-μm columns in the first dimension in conjunction with several 3.0?mm?×?50?mm RP columns packed with sub-3-μm fully porous particles in the second dimension. Multiple combinations of separation modes coupled to UV and MS detection are applied to the LC?×?LC analysis of a protein standard mixture, intended to be representative of protein drug substances. The results reported in this study demonstrate that our automated online multicolumn 2D-LC-DAD-MS workflow can be a powerful tool for comprehensive chromatographic column screening that enables the semi-automated development of 2D-LC methods, offering the ability to streamline full visualization of sample composition for an unknown complex mixture while maximizing chromatographic orthogonality.Piette, B.M.A.G., Heddle, J.G., 2020. A peptide–nucleic acid replicator origin for life. Trends in Ecology & Evolution 35, 397-406. requires self-replication. But, what was the very first self-replicator directly ancestral to all life? The currently favoured RNA World theory assigns this role to RNA alone but suffers from a number of seemingly intractable problems. Instead, we suggest that the self-replicator consisted of both peptides and nucleic acid strands. Such a nucleopeptide replicator is more feasible both in the light of the replication machinery currently found in cells and the complexity of the evolutionary path required to reach them. Recent theoretical and mathematical work supports this idea and provide a blueprint for future investigations.Pisarzowska, A., Rakociński, M., Marynowski, L., Szczerba, M., Thoby, M., Paszkowski, M., Perri, M.C., Spalletta, C., Sch?nlaub, H.-P., Kowalik, N., Gereke, M., 2020. Large environmental disturbances caused by magmatic activity during the Late Devonian Hangenberg Crisis. Global and Planetary Change 190, 103155. wide range of various proxies (e.g., mineralogy, organic carbon, inorganic geochemistry, C and Mo isotopes, and framboidal pyrite) were applied for interpretation of changing oceanic redox conditions, bioproductivity, and the regional history of magmatic activity. This resulted in internally consistent interpretation of the late Famennian Hangenberg Crisis in subtropical deepest water sites of the epeiric Rhenohercynian and Saxo–Thuringian basins, as well as more open sites of the Paleo-Tethys Ocean.High mercury concentrations were detected in all of the studied sections, with the highest values strata in the Carnic Alps (up to 20 ppm) and Thuringia (up to 1.5 ppm). The beginning of the Hg anomaly and the presence of pyroclastic material, indicate that local magmatic activity was initiated before the deposition of the Hangenberg Black Shale (HBS). The onset of the HBS deposition coincided with the expansion of phosphate-enriched, anoxic to euxinic waters during short-lived CO2-greenhouse spike of a warm–humid climate. Intensive magmatic activity was a trigger for climatic changes, an excessive eutrophication, and an accelerated burial of organic carbon during the Hangenberg transgressive pulse. The injection of catastrophic amounts of CO2, toxic elements and acids from volcanic activity could have led to acidification, mutation of spores, and episodes of mass mortality of marine plankton.Plet, C., Grice, K., Scarlett, A.G., Ruebsam, W., Holman, A.I., Schwark, L., 2020. Aromatic hydrocarbons provide new insight into carbonate concretion formation and the impact of eogenesis on organic matter. Organic Geochemistry 143, 103961. of aromatic biomarkers extracted from carbonate concretions can contribute to characterize the enhanced microbial activity that mediates carbonate concretion formation. This microbial footprint can be further inferred from the stable isotopic values of carbonate (δ13C) and pyrite (δ34S). Here, we used a combination of GC-MS and GC×GC-ToF-MS to compare the aromatic fractions of two Toarcian carbonate concretions from the H. falciferum ammonite zone of the Posidonia Shale (SW-Germany) and their host sediment. The results revealed that n-alkylated and phytanyl arenes were enhanced in the concretions relative to the host sediment. These findings support a very early diagenetic (eogenetic) microbial source for alkylated and phytanyl arenes derived from the microbial ecosystem mediating concretion formation. In contrast, aromatic compounds formed by thermal maturation (e.g. polycyclic aromatic hydrocarbons, aromatic steroids, organic sulphur compounds) remained invariant in host rock and concretion samples. When combined with bulk sediment and concretion properties, the distribution of aromatic compounds indicates that eogenetic microbial activity upon concretion growth does not diminish organic matter quality.Pondell, C.R., Canuel, E.A., 2020. Sterol, fatty acid, and lignin biomarkers identify the response of organic matter accumulation in Englebright Lake, California (USA) to climate and human impacts. Organic Geochemistry 142, 103992. change is one of the biggest challenges facing humankind. Higher temperatures and changes in precipitation will lead to a greater frequency of drought, wildfire, and intense storms that will threaten systems already vulnerable to climate and anthropogenic change. These threats will transform carbon delivery across the terrestrial–aquatic interface. This study investigated how anthropogenic activities and climate influence organic carbon delivery using Englebright Lake, a reservoir in California, as a model system. Organic carbon accumulation in three depositional settings (bottomset, foreset, topset) was analyzed using fatty acid, sterol and lignin biomarkers and compared to records of watershed events to determine responses to dam construction, mining impacts and flood events. Concentrations of long chain saturated fatty acids, plant sterols, epi-brassicasterol/brassicasterol and lignin biomarkers increased by an order of magnitude in foreset deposits in response to flood events (p?<?0.007 for each biomarker). Hydraulic mining for gold was recorded as near-zero concentrations of terrigenous biomarkers in topset deposits, whereas decreases in diacids coincident with increases in aquatic sterols in bottomset deposits reflected the response to dam construction (p?<?0.007 for each biomarker). Organic carbon accumulation was controlled by event magnitude and duration, and climate-driven event signals were up to an order of magnitude larger than anthropogenic-driven event signals. These data demonstrate the importance of understanding the depositional environment because the ability to characterize three different depositional settings in Englebright Lake enabled us to identify the smaller anthropogenic signals that would have been obscured by the much larger response to climate events.Prasad, P.S.R., Kiran, B.S., 2020. Stability and exchange of guest molecules in gas hydrates under the influence of CH4, CO2, N2 and CO2+N2 gases at low-pressures. Journal of Natural Gas Science and Engineering 78, 103311. recovery from the natural gas hydrate (NGH) deposits is a current topic of interest. Apart from the conventional thermal stimulation, depressurisation and chemical injection methods, the guest molecular replacement method in hydrates offers dual advantage such as retention of their structural stability, and as a sink for carbon dioxide (CO2). However, the molecular exchangeability shows significant variance and the mechanism is also incomprehensible. This study is aimed at probing the stability of gas (CH4 & CO2) hydrates in the presence of CO2/CH4, N2 and their mixtures at low-pressure (~1.0 MPa) conditions. The selected experimental conditions help gain insight into the guest-guest exchange. Evaluation of gas pressure during the dissociation process indicates the presence of mixed hydrates. The micro-Raman investigations elucidate the occurrence of mixed hydrate seed crystals, encasing both CH4/CO2 molecules of initial hydrates, and also the molecules from the injected gas. The characteristic signatures of CH4 & CO2 molecules in hydrate systems broadly agree with the literature data, while that of N2 pointedly closer to the gas phase signature, indicating its role as a help-gas to promote replacement/rearrangement of guests in hydrate lattice.Preiner, M., Igarashi, K., Muchowska, K.B., Yu, M., Varma, S.J., Kleinermanns, K., Nobu, M.K., Kamagata, Y., Tüysüz, H., Moran, J., Martin, W.F., 2020. A hydrogen-dependent geochemical analogue of primordial carbon and energy metabolism. Nature Ecology & Evolution 4, 534–542. gas, H2, is generated by alkaline hydrothermal vents through an ancient geochemical process called serpentinization, in which water reacts with iron-containing minerals deep within the Earth’s crust. H2 is the electron donor for the most ancient and the only energy-releasing route of biological CO2 fixation, the acetyl-CoA pathway. At the origin of metabolism, CO2 fixation by hydrothermal H2 within serpentinizing systems could have preceded and patterned biotic pathways. Here we show that three hydrothermal minerals—greigite (Fe3S4), magnetite (Fe3O4) and awaruite (Ni3Fe)—catalyse the fixation of CO2 with H2 at 100?°C under alkaline aqueous conditions. The product spectrum includes formate (up to 200?mM), acetate (up to 100??M), pyruvate (up to 10??M), methanol (up to 100??M) and methane. The results shed light on both the geochemical origin of microbial metabolism and the nature of abiotic formate and methane synthesis in modern hydrothermal vents.Prouty, N.G., Campbell, P.L., Close, H.G., Biddle, J.F., Beckmann, S., 2020. Molecular indicators of methane metabolisms at cold seeps along the United States Atlantic Margin. Chemical Geology 543, 119603. oxidation of methane (AOM) and the environmental conditions supporting AOM on continental margins is an essential component to global methane budgets. Diagnostic lipid biomarkers and their compound specific isotope analysis preserved in authigenic carbonates at cold seeps can serve as “fingerprints” to archaeal?bacterial consortia involved in AOM. However, despite the discovery of several hundreds of seeps along the United States Atlantic Margin (USAM), there are relatively few biomarker investigations of cold seep carbonates along this passive margin. A lipid biomarker, carbon isotope, and DNA marker gene study was therefore undertaken to determine the microbial origins of authigenic carbonates from two USAM seeps, Norfolk and the Baltimore Canyon seep fields. Results from this study capture a distinct archaeal lipid signature from putative methanotrophic archaea, including archaeol (I), sn-2-hydroxyarchaeol, 2,6,10,15,19-pentamethylicosane (PMI), and crocetane. The 13C-depleted AOM-related archaeal lipid samples (i.e., archaeol: ?91.6‰, sn-2-hydroxyarchaeol: ?129.2‰, PMI ?92.8‰, and crocetane: ?70.9‰) confirm the dominance of methane assimilation and isotope fractionation during AOM. These results are consistent with the detection of archaeal anaerobic methanotrophs (ANMEs) based on 16S rRNA gene sequencing. The Norfolk authigenic carbonate contained ANME-1a, -1b, 2a-2b, and 2c whereas only the ANME-2 clade was detected at Baltimore and present as the subclusters 2a-2b and -2b. The ANME-2d clade may also be present, particularly at the Baltimore seep site, given the high abundance of Candidatus Methanoperedens nitroreducens detected in the mcrA gene sequencing. The presence of terminally branched fatty acids, antesio- and iso-C15:0 components, as well as C16:1ω7 with δ13C values as low as ?107.6‰, are indicative of sulfate-reducing bacteria (SRB) at the Norfolk seep site and supports syntrophy of SRB with methane-oxidizing archaea. In contrast, nitrate-driven AOM in syntrophy M. nitroreducens at the Baltimore seep site is consistent with elevated fatty acid δ13C values and lack of Deltaproteobacteria at the Baltimore seep site. Taken together, the range in lipid composition, distribution, and carbon isotopic composition observed at the Norfolk and Baltimore seep sites suggests AOM is performed by multiple archaea instead of a single species and may be paired with either or both nitrate- and sulfate-reduction. Given the heterogeneous nature of cold seep ecosystems, this study fills a critical spatial gap in our knowledge of AOM activity at two seep sites along a passive margin.Pulster, E.L., Gracia, A., Armenteros, M., Toro-Farmer, G., Snyder, S.M., Carr, B.E., Schwaab, M.R., Nicholson, T.J., Mrowicki, J., Murawski, S.A., 2020. A first comprehensive baseline of hydrocarbon pollution in Gulf of Mexico fishes. Scientific Reports 10, 6437. over seven decades of production and hundreds of oil spills per year, there were no comprehensive baselines for petroleum contamination in the Gulf of Mexico (GoM) prior to this study. Subsequent to the 2010 Deepwater Horizon (DWH) spill, we implemented Gulf-wide fish surveys extending over seven years (2011–2018). A total of 2,503 fishes, comprised of 91 species, were sampled from 359 locations and evaluated for biliary polycyclic aromatic hydrocarbon (PAH) concentrations. The northern GoM had significantly higher total biliary PAH concentrations than the West Florida Shelf, and coastal regions off Mexico and Cuba. The highest concentrations of biliary PAH metabolites occurred in Yellowfin Tuna (Thunnus albacares), Golden Tilefish (Lopholatilus chamaeleonticeps), and Red Drum (Sciaenops ocellatus). Conversely, biliary PAH concentrations were relatively low for most other species including economically important snappers and groupers. While oil contamination in most demersal species in the north central GoM declined in the first few years following DWH, more recent increases in exposure to PAHs in some species suggest a complex interaction between multiple input sources and possible re-suspension or bioturbation of oil-contaminated sediments. This study provides the most comprehensive baselines of PAH exposure in fishes ever conducted for a large marine ecosystem.Qanbari-Taheri, N., Karimy, A.H., Holakooei, P., Kobarfard, F., 2020. Organic residue analysis of Iron Age ceramics from the archaeological site of Kani-zirin, western Iran. Archaeometry 62, 612-625. residue analysis of potshards excavated from the Iron Age archaeological site of Kani-zirin, western Iran, was achieved with acidified methanol extraction and gas chromatography-mass spectrometry (GC-MS). The GC-MS data showed plant and animal commodities incorporated in the shards. Also, the investigations confirmed the presence of plant resin together with a tartrate ion within a group of the shards, suggesting a probable use of grape-related products. Evidence of resins from the Pinaceae family, as an exotic species in Iran, was evinced in several of the shards.Qin, X.-q., Yao, B., Jin, L., Zheng, X.-z., Ma, J., Benedetti, M.F., Li, Y., Ren, Z.-l., 2020. Characterizing soil dissolved organic matter in typical soils from China using fluorescence EEM–PARAFAC and UV–visible absorption. Aquatic Geochemistry 26, 71-88. organic matter (DOM) strongly participates in a variety of critical environmental and ecological processes and has a large impact on environmental quality. In this study, ultraviolet–visible absorbance spectroscopy and excitation–emission matrices of fluorescence spectroscopy in combination with parallel factor analysis (EEMs–PARAFAC) were applied to characterize a total of 92 DOM samples extracted from four typical soil types under three different land-use regimes across China. DOC concentrations ranged from 6.52?±?1.09 to 25.62?±?4.83 mg L?1 and were generally higher in red soil from Guangdong and Guangxi, especially in paddy soil. Three fluorescence components were identified in soil DOM by EEMs–PARAFAC, including high molecular weight UVA humic-like substances (C1), low molecular weight autochthonous humic-like substances (C2), and protein-like substances (C3). DOM from black soil in Heilongjiang, purple soil from Sichuan, and red soil from Zhejiang had more humic-like substances, whereas DOM from yellow soil in Guizhou and red soil from Guangdong and Guangxi had lower degree of aromaticity and higher proportion of microbial-derived protein-like components (C3). Moreover, DOM from paddy soil tended to be more of protein-like components (C3) than that from other land uses and DOM from dryland soil generally had more autochthonous humic-like substances (C2). Our results demonstrated that soil DOM characteristics both varied significantly by soil type and land use, and EEMs–PARAFAC could be a useful approach to characterize the components and sources of heterogeneous DOM in soils.Qin, Z., Zhao, Z., Jiao, W., Han, Z., Xia, L., Fang, Y., Wang, S., Ji, L., Jiang, Y., 2020. Coupled photocatalytic-bacterial degradation of pyrene: Removal enhancement and bacterial community responses. Environmental Research 183, 109135. aromatic hydrocarbons (PAHs) are a class of pollutants that ubiquitously present in environment and hard to be degraded by microorganisms. Herein, we reported a novel photocatalytic-bacterial coupled removal system to treat PAH-polluted water. Using pyrene as the model pollutant, we demonstrated that the removal percentage of different groups was in order: 63.89% ± 1.03% (Vis-Biological) > 61.27% ± 1.08% (UV-Biological) > 59.58% ± 1.15% (UV) > 57.41% ± 1.13% (Vis) > 6.65% ± 0.72% (Biological) > 1.70% ± 0.34% (Control), showing the coupled system significantly improved the removal percentage of pyrene. Additionally, we observed that the coupled system driven by visible light showed higher removal percentage than UV light, exhibiting a good potential for future application. Sequencing analysis of 16S rRNA genes showed that alpha diversity (richness, evenness and diversity) got promoted and data of the relative abundance showed that Pseudomonadaceae was substituted as the dominant bacteria for Planococcaceae, with some other functional bacteria quickly acclimatizing in the bacterial community. Difference analysis indicated that over half of top fifteen genera were generally different significantly (p < 0.001) among two different samples, and UV light altered structure and composition of bacterial community more than visible light. Functional features’ change suggested that the bacterial community not only protected itself but also participated in degrading pyrene. Overall, our study offered a new method for PAH degradation and contributed to further understanding of coupled catalytic-bacterial degradation processes.Qiu, L., Yan, D.-P., Xu, H., Shi, H., Dong, W., Sun, S., 2020. Late Cretaceous mud volcanism in the southwestern Songliao basin records slab rollback of the subducted paleo-Pacific Plate underneath NE China. Journal of Asian Earth Sciences: X 3, 100028. present a new seismic reflection dataset and use it to characterize fossil mud volcanoes in the southwestern Songliao graben basin in northeastern China. The results reveal a link between mud volcanism and slab rollback along the eastern Asian margin. This study focuses on the upper 3?km of the Lujiapu sub-basin, which lies in the southwestern Songliao basin. The base of the sequence consists of Lower Cretaceous siliciclastic deposits that are penetrated by mud volcano fluidization pipes. These deposits are overlain by Upper Cretaceous strata that have been deformed by the mud volcanoes. The sequence is capped by undeformed Neogene–Quaternary sediments. These observations constrain the timing of mud volcanism to the Santonian–Campanian (~87–72?Ma). During Late Cretaceous diapirism, normal faulting at the tops of the mud volcanoes formed horsts and grabens. Surface anticlines and inversion structures near the mud volcano source layer indicate that basin inversion occurred during deposition of the Sifangtai and Mingshui formations (Campanian). Similar structures are also identified in the central Songliao basin. Thus, we propose that slab flattening to deepening during paleo-Pacific Plate subduction led to basin inversion. This process triggered the migration of high-pressure fluids and brecciated plastic rocks along pre-existing normal faults, which in turn produced the mud volcano system.Qu, Y., van Zuilen, M.A., Lepland, A., 2020. Hydrothermal circulation and oil migration at the root of the heterogeneous micro-structure of carbonaceous material in the 2.0?Ga Zaonega Formation, Onega Basin, Russia. Precambrian Research 343, 105705. rocks of the 2.0 Ga Zaonega Formation, Karelia, Russia, have been studied extensively to gain understanding of the global carbon cycle and reconstruction of paleo-environments, directly after the Great Oxidation Event (GOE). This formation has a complex history of alteration, involving pervasive hydrothermal circulation, hydrocarbon generation/migration, and mineral authigenesis. Several previous studies have focused on the description of these secondary effects, and the identification of primary geochemical signals in the carbonaceous phases. Migration and infiltration of organic-rich fluids appear to have had only limited effect on the primary carbon isotope record (δ13Corg). However, the structural variability of carbonaceous material (CM) appears to have been strongly affected, with a range of reported structures including carbon onion-shaped nanostructures and mineral-templated graphite films. Here we present a systematic Raman spectroscopy-based study of the structural variability of CM in a drill core representing the middle and upper strata of the Zaonega Formation. The Raman spectra of CM show a systematic difference in structural order between the bulk carbonaceous matrix (Matrix-CM) and the CM occurring near mineral contacts (Contact-CM), indicating that mineral templating was an important process affecting structural order in the formation. The templating effect was observed on the surface of a wide range of minerals. The difference in structural order between Matrix-CM and Contact-CM can be traced throughout the ca. 400 m stratigraphy. The structural order varied with the degree of alteration and hydrothermal circulation, from highly ordered structures directly above a large gabbro intrusion at the bottom of the stratigraphy to less ordered structures higher up in the sequence. This trend directly correlates with the δ18O trend of secondary calcite, and can be attributed to the decreasing influence and temperature regime of hydrothermal circulation upward in the stratigraphy. The results presented here suggest that organic-rich hydrothermal fluids can locally strongly enhance graphitization of carbonaceous materials, and cause sample-scale heterogeneities in the structural order of organic materials. This has implications for the interpretation of carbonaceous materials in other ancient rocks experiencing circulation of organic-rich hydrothermal fluids.Quehenberger, J., Pittenauer, E., Allmaier, G., Spadiut, O., 2020. The influence of the specific growth rate on the lipid composition of Sulfolobus acidocaldarius. Extremophiles 24, 413-420. lipids are constituted of two isoprenoid chains connected via ether bonds to glycerol in the sn-2, 3 position. Due to these unique properties archaeal lipids are significantly more stable against high temperature, low pH, oxidation and enzymatic degradation than conventional lipids. Additionally, in members of the phylum Crenarchaeota condensation of two (monopolar) archaeal diether lipids to a single (bipolar) tetraether lipid as well as formation of cyclopentane rings in the isoprenoid core strongly reduce permeability of the crenarchaeal membranes. In this work we show that the Crenarchaeum Sulfolobus acidocaldarius changes its lipid composition as reaction to a shift in growth rate caused by nutrient limitation. We thereby identified a novel influencing factor for the lipid composition of S. acidocaldarius and were able to determine the effect of this factor on the lipid composition by using MALDI-MS for the semi-quantification of an archaeal lipidome: a shift in the specific growth rate during a controlled continuous cultivation of S. acidocaldarius from 0.011 to 0.035 h?1 led to a change in the ratio of diether to tetraether lipids from 1:3 to 1:5 and a decrease of the average number of cyclopentane rings from 5.1 to 4.6.Queiroz, L.L., Bendia, A.G., Duarte, R.T.D., das Gra?as, D.A., da Costa da Silva, A.L., Nakayama, C.R., Sumida, P.Y., Lima, A.O.S., Nagano, Y., Fujikura, K., Kitazato, H., Pellizari, V.H., 2020. Bacterial diversity in deep-sea sediments under influence of asphalt seep at the S?o Paulo Plateau. Antonie van Leeuwenhoek 113, 707-717. we investigated the diversity of bacterial communities from deep-sea surface sediments under influence of asphalt seeps at the Sao Paulo Plateau using next-generation sequencing method. Sampling was performed at North S?o Paulo Plateau using the human occupied vehicle Shinkai 6500 and her support vessel Yokosuka. The microbial diversity was studied at two surficial sediment layers (0–1 and 1–4?cm) of five samples collected in cores in water depths ranging from 2456 to 2728?m. Bacterial communities were studied through sequencing of 16S rRNA gene on the Ion Torrent platform and clustered in operational taxonomic units. We observed high diversity of bacterial sediment communities as previously described by other studies. When we considered community composition, the most abundant classes were Alphaproteobacteria (27.7%), Acidimicrobiia (20%), Gammaproteobacteria (11.3%) and Deltaproteobacteria (6.6%). Most abundant OTUs at family level were from two uncultured bacteria from Actinomarinales (5.95%) and Kiloniellaceae (3.17%). The unexpected high abundance of Alphaproteobacteria and Acidimicrobiia in our deep-sea microbial communities may be related to the presence of asphalt seep at North S?o Paulo Plateau, since these bacterial classes contain bacteria that possess the capability of metabolizing hydrocarbon compounds.Quesnel, Y., Zylberman, W., Rochette, P., Uehara, M., Gattacceca, J., Osinski, G.R., Dussouillez, P., Lepaulard, C., Champollion, C., 2020. Geophysical signature of the Tunnunik impact structure, Northwest Territories, Canada. Meteoritics & Planetary Science 55, 480-495.: In 2011, the discovery of shatter cones confirmed the 28 km diameter Tunnunik complex impact structure, Northwest Territories, Canada. This study presents the first results of ground‐based electromagnetic, gravimetric, and magnetic surveys over this impact structure. Its central area is characterized by a ~10 km wide negative gravity anomaly of about 3 mGal amplitude, roughly corresponding to the area of shatter cones, and associated with a positive magnetic field anomaly of ~120 nT amplitude and 3 km wavelength. The latter correlates well with the location of the deepest uplifted strata, an impact‐tilted Proterozoic dolomite layer of the Shaler Supergroup exposed near the center of the structure and intruded by dolerite dykes. Locally, electromagnetic field data unveil a conductive superficial formation which corresponds to an 80–100 m thick sand layer covering the impact structure. Based on the measurements of magnetic properties of rock samples, we model the source of the magnetic anomaly as the magnetic sediments of the Shaler Supergroup combined with a core of uplifted crystalline basement with enhanced magnetization. More classically, the low gravity signature is attributed to a reduction in density measured on the brecciated target rocks and to the isolated sand formations. However, the present‐day fractured zone does not extend deeper than ~1 km in our model, indicating a possible 1.5 km of erosion since the time of impact, about 430 Ma ago.Plain Language Summary: This study reveals the geophysical signature of the buried structure of an eroded impact crater, Tunnunik, located in Northwest Territories, Canada. A positive magnetic anomaly was detected at the center, showing the uplift of some deep geological formations and the possible presence of strongly magnetized basement. A negative gravimetric anomaly is also observed, mostly corresponding to the fracturing/brecciation of the impacted rocks inside the crater. Using numerical models constrained by laboratory measurements on rock samples, the physical properties and geometry of the buried geological formations are estimated. An important implication of this study is the link between the geophysical remains of an impact crater and the postimpact erosion.Raanan, H., Poudel, S., Pike, D.H., Nanda, V., Falkowski, P.G., 2020. Small protein folds at the root of an ancient metabolic network. Proceedings of the National Academy of Sciences 117, 7193-7199. dissipates energy far from thermodynamic equilibrium via electron transport systems that are coupled to external sources of oxidants and reductants. Biological electron transport, in turn, is catalyzed by a suite of enzymes that comprise the superfamily of oxidoreductases. The origin of oxidoreductases is enigmatic. Comparing protein topology and the sequence of modern oxidoreductases, we deduce a putative common ancestor that may have existed at the earliest stages of metabolism. Through duplication, recruitment of other proteins, and diversification, this ancestral protein may have evolved to facilitate electron transfer and redox catalysis at a very early stage in the origin of metabolism.Abstract: Life on Earth is driven by electron transfer reactions catalyzed by a suite of enzymes that comprise the superfamily of oxidoreductases (Enzyme Classification EC1). Most modern oxidoreductases are complex in their structure and chemistry and must have evolved from a small set of ancient folds. Ancient oxidoreductases from the Archean Eon between ca. 3.5 and 2.5 billion years ago have been long extinct, making it challenging to retrace evolution by sequence-based phylogeny or ancestral sequence reconstruction. However, three-dimensional topologies of proteins change more slowly than sequences. Using comparative structure and sequence profile-profile alignments, we quantify the similarity between proximal cofactor-binding folds and show that they are derived from a common ancestor. We discovered that two recurring folds were central to the origin of metabolism: ferredoxin and Rossmann-like folds. In turn, these two folds likely shared a common ancestor that, through duplication, recruitment, and diversification, evolved to facilitate electron transfer and catalysis at a very early stage in the origin of metabolism.Rach, O., Hadeen, X., Sachse, D., 2020. An automated solid phase extraction procedure for lipid biomarker purification and stable isotope analysis. Organic Geochemistry 142, 103995. recovery and high purity of lipid biomarkers are essential for compound-specific stable isotope analysis in a variety of fields ranging from hydrocarbon research, paleoclimatology, food and drug analysis and medicine. Solid-phase extraction (SPE) is the most common method for purifying organic compounds from complex mixtures. SPE constitutes the most labor-intensive part of laboratory work often limiting the number of samples that can be analyzed. Reliable, easy-to-use, automated methods could increase sample throughput as well as reproducibility. Here we introduce such a method using a Gilson ASPEC GX-271 system and test the separation quality, reproducibility, and efficiency in comparison to a classical manual SPE lipid purification procedure. Using multiple extractions of the same natural soil sample we show that the automated SPE is comparable in overall quality and slightly superior in reproducibility to a manual SPE. We demonstrate that stable hydrogen isotope measurements of n-alkanes purified using an automated SPE extraction showed significantly lower standard errors. Furthermore, the unattended operation of the system eases the purification of large sample sets. Generally, the automated SPE using the Gilson ASPEC GX-271 for lipid biomarker separation provides qualitatively and quantitatively accurate and reproducible results with more efficient purification of compounds than the manual method.Racimo, F., Woodbridge, J., Fyfe, R.M., Sikora, M., Sj?gren, K.-G., Kristiansen, K., Vander Linden, M., 2020. The spatiotemporal spread of human migrations during the European Holocene. Proceedings of the National Academy of Sciences 117, 8989-9000.ps://10.1073/pnas.1920051117Significance: We present a study to model the spread of ancestry in ancient genomes through time and space and a geostatistical framework for comparing human migrations and land-cover changes, while accounting for changes in climate. We show that the two major migrations during the European Holocene had different spatiotemporal structures and expansion rates. In addition, we find that the Yamnaya expansion had a stronger association with vegetational landscape changes than the earlier Neolithic farmer expansion. Our approach paves the way for future work linking paleogenomics with other archaeometric datasets in the study of the past.Abstract: The European continent was subject to two major migrations of peoples during the Holocene: the northwestward movement of Anatolian farmer populations during the Neolithic and the westward movement of Yamnaya steppe peoples during the Bronze Age. These movements changed the genetic composition of the continent’s inhabitants. The Holocene was also characterized by major changes in vegetation composition, which altered the environment occupied by the original hunter-gatherer populations. We aim to test to what extent vegetation change through time is associated with changes in population composition as a consequence of these migrations, or with changes in climate. Using ancient DNA in combination with geostatistical techniques, we produce detailed maps of ancient population movements, which allow us to visualize how these migrations unfolded through time and space. We find that the spread of Neolithic farmer ancestry had a two-pronged wavefront, in agreement with similar findings on the cultural spread of farming from radiocarbon-dated archaeological sites. This movement, however, did not have a strong association with changes in the vegetational landscape. In contrast, the Yamnaya migration speed was at least twice as fast and coincided with a reduction in the amount of broad-leaf forest and an increase in the amount of pasture and natural grasslands in the continent. We demonstrate the utility of integrating ancient genomes with archaeometric datasets in a spatiotemporal statistical framework, which we foresee will enable future studies of ancient populations’ movements, and their putative effects on local fauna and flora.Racki, G., 2020. A volcanic scenario for the Frasnian–Famennian major biotic crisis and other Late Devonian global changes: More answers than questions? Global and Planetary Change 189, 103174. the prime causation of the Late Devonian Frasnian–Famennian (F–F) mass extinction remains conjectural, such destructive factors as the spread of anoxia and rapid upheavals in the runaway greenhouse climate are generally accepted in the Earth-bound multicausal scenario. In terms of prime triggers of these global changes, volcanism paroxysm coupled with the Eovariscan tectonism has been suspected for many years. However, the recent discovery of multiple anomalous mercury enrichments at the worldwide scale provides a reliable factual basis for proposing a volcanic–tectonic scenario for the stepwise F–F ecological catastrophe, specifically the Kellwasser (KW) Crisis. A focus is usually on the cataclysmic emplacement of the Viluy large igneous province (LIP) in eastern Siberia. However, the long-lasted effusive outpouring was likely episodically paired with amplified arc magmatism and hydrothermal activity, and the rapid climate oscillations and glacioustatic responses could in fact have been promoted by diverse feedbacks driven by volcanism and tectonics. The anti-greenhouse effect of expanding intertidal–estuarine and riparian woodlands during transient CO2-greenhouse spikes was another key feedback on Late Devonian land. An updated volcanic press-pulse model is proposed with reference to the recent timing of LIPs and arc magmatism and the revised date of 371.9 Ma for the F–F boundary. The global changes were initiated by the pre-KW effusive activity of LIPs, which caused extreme stress in the global carbonate ecosystem. Nevertheless, at least two decisive pulses of sill-type intrusions and/or kimberlite/carbonatite eruptions, in addition to flood basalt extrusions on the East European Platform, are thought to have eventually led to the end-Frasnian ecological catastrophe. These stimuli have been enhanced by effective orbital modulation. An attractive option is to apply the scenario to other Late Devonian global events, as evidences in particular by the Hg spikes that coincide with the end-Famennian Hangenberg Crisis.Rakociński, M., Marynowski, L., Pisarzowska, A., Be?dowski, J., Siedlewicz, G., Zatoń, M., Perri, M.C., Spalletta, C., Sch?nlaub, H.P., 2020. Volcanic related methylmercury poisoning as the possible driver of the end-Devonian mass extinction. Scientific Reports 10, 7344. end-Devonian global Hangenberg event (359?Ma) is among the most devastating mass extinction events in Earth’s history, albeit not one of the “Big Five”. This extinction is linked to worldwide anoxia caused by global climatic changes. These changes could have been driven by astronomical forcing and volcanic cataclysm, but ultimate causes of the extinction still remain unclear. Here we report anomalously high mercury (Hg) concentration in marine deposits encompassing the Hangenberg event from Italy and Austria (Carnic Alps). The Hangenberg event recorded in the sections investigated can be here interpreted as caused by extensive volcanic activity of large igneous provinces (LIPs), arc volcanism and/or hydrothermal activity. Our results (very large Hg anomalies) imply volcanism as a most possible cause of the Hangenberg event, similar to other first order mass extinctions during the Phanerozoic. For the first time we show that apart from anoxia, proximate kill mechanism of aquatic life during the event could have been methylmercury formed by biomethylation of a volcanically derived, huge concentration of inorganic Hg supplied to the ocean. Methylmercury as a much more toxic Hg form, potentially could have had a devastating impact on end-Devonian biodiversity, causing the extinction of many pelagic species.Ramírez, V., Munive, J.-A., Cortes, L., Mu?oz-Rojas, J., Portillo, R., Baez, A., 2020. Long-chain hydrocarbons (C21, C24, and C31) released by Bacillus sp. MH778713 break dormancy of mesquite seeds subjected to chromium stress. Frontiers in Microbiology 11, 741. doi: 10.3389/fmicb.2020.00741. organic compounds (VOCs) produced by rhizobacteria have been proven to stimulate plant growth during germination and seedling stages. However, the modulating effect of bacterial volatiles on the germination of seeds subjected to heavy metal stress is scarcely studied. In this work, the ability of volatiles released by Bacillus sp. MH778713 to induce seed dormancy breakage in Prosopis laevigata and Arabidopsis thaliana seeds were examined. The minimal inhibitory concentration of chromium (Cr) VI that prevents seed germination of P. laevigata and A. thaliana on water-Cr-agar plates was 2500 and 100 mg L–1, respectively. Remarkably, partitioned Petri-dish co-cultivation of Bacillus sp. MH778713 and plant seeds under Cr-stress showed the beneficial effect of volatiles emitted by Bacillus sp. MH778713, helping plant seeds to overcome Cr-stress. Among the metabolites emitted by Bacillus sp. MH778713, octadecane, heneicosane, 2,4-di-tert-butylphenol, hexadecane, eicosane, octacosane, and tetratriacontane were the most abundant. To confirm that these long-chain compounds produced by Bacillus sp. MH778713 could be responsible for the seed dormancy breakage, high pure organic compounds (2,4-di-tert-butylphenol, heneicosane, hentriacontane, and tetracosane) were used directly in germination assays of P. laevigata and A. thaliana seeds instead of volatiles emitted by Bacillus sp. MH778713. All organic compounds allowed Prosopis and Arabidopsis seeds to overcome Cr-toxicity and germinate. The results of this study provide new insight into the role of long-chain bacterial compounds produced by Bacillus sp. MH778713 as triggers of seed abiotic stress tolerance, surmounting chromium stress and stimulating seedling development.Rathore, S., Bindoff, N.L., Phillips, H.E., Feng, M., 2020. Recent hemispheric asymmetry in global ocean warming induced by climate change and internal variability. Nature Communications 11, 2008. research shows that 90% of the net global ocean heat gain during 2005–2015 was confined to the southern hemisphere with little corresponding heat gain in the northern hemisphere ocean. We propose that this heating pattern of the ocean is driven by anthropogenic climate change and an asymmetric climate variation between the two hemispheres. This asymmetric variation is found in the pre-industrial control simulations from 11 climate models. While both layers (0–700?m and 700–2000?m) experience steady anthropogenic warming, the 0–700?m layer experiences large internal variability, which primarily drives the observed hemispheric asymmetry of global ocean heat gain in 0–2000?m layer. We infer that the rate of global ocean warming is consistent with the climate simulations for this period. However, the observed hemispheric asymmetry in heat gain can be explained by the Earth’s internal climate variability without invoking alternate hypotheses, such as asymmetric aerosol loading.Ray, D.C., Jarochowska, E., R?stel, P., Worton, G., Munnecke, A., Wheeley, J.R., Boomer, I., 2020. High-resolution correlation of the Homerian carbon isotope excursion (Silurian) across the interior of the Midland Platform (Avalonia), UK. Geological Magazine 157, 603-620 δ13Ccarb and microfacies data from Hereford–Worcestershire and the West Midlands allow for a detailed examination of variations in the Homerian carbon isotope excursion (Silurian) and depositional environment within the Much Wenlock Limestone Formation of the Midland Platform (Avalonia), UK. These comparisons have been aided by a detailed sequence-stratigraphic and bentonite correlation framework. Microfacies analysis has identified regional differences in relative sea-level change and indicates an overall shallowing of the carbonate platform interior from Hereford–Worcestershire to the West Midlands. Based upon the maximum δ13Ccarb values for the lower and upper peaks of the Homerian carbon isotope excursion (CIE), the shallower depositional setting of the West Midlands is associated with values that are 0.7 ‰ and 0.8 ‰ higher than in Hereford–Worcestershire. At the scale of parasequences the effect of depositional environment upon δ13Ccarb values can also be observed, with a conspicuous offset in the position of the trough in δ13Ccarb values between the peaks of the Homerian CIE. This offset can be accounted for by differences in relative sea-level change and carbonate production rates. While such differences complicate the use of CIEs as a means of high-resolution correlation, and caution against correlations based purely upon the isotopic signature, it is clear that a careful analysis of the depositional environment can account for such differences and thereby improve the use of carbon isotopic curves as a means of correlation.Raza, A., Gholami, R., Rabiei, M., Rasouli, V., Rezaee, R., 2020. Injection rate estimation to numerically assess CO2 sequestration in depleted gas reservoirs. Energy Sources, Part A: Recovery, Utilization, and Environmental Effects 42, 1608-1617. gas reservoirs are known as geological media for the sequestration of carbon dioxide (CO2). A large amount of studies attempting to estimate the injection rate of CO2 by analytical and numerical modeling but selection of a suitable injection rate based on the effect of the remaining gas has not been fully understood for in depleted gas fields. This study attempts to present a scheme to estimate the injection rate for CO2 sequestration in depleted gas reservoirs which can help to avoid the lengthy simulation time often required. An analytical method was suggested to estimate the favorable steady-state injection rate for three-phase system (CO2-gas-brine). For the sequestration, CO2 was injected at the estimated and overestimated injection rate to evaluate their impacts on the storage injectivity and capacity. The results obtained indicated that the injection rate estimation approach proposed can be a great asset to evaluate the injectivity and the sequestration potential of the depleted gas reservoirs.Ren, Z., Guo, M., Cheng, Y., Sun, W., Li, G., Dong, M., Li, Y., Xi, Z., Pei, X., Niu, H., Tan, G., Zhou, Z., Huang, Z., 2020. Design of a compact time-of-flight mass spectrometer for space application. Journal of the American Society for Mass Spectrometry 31, 434-440. miniature reflectron time-of-flight mass spectrometer (TOF MS) with orthogonal extraction coupled with electron impact (EI) ionization source can be used to perform in situ gas composition analysis in a planetary environment. However, performances such as the mass resolution, sensitivity, limit of detection, mass range, and mass accuracy are often decreased because of miniaturization. Herein, a compact instrument for space applications has been developed, and its performance has been evaluated. The mass of the TOF MS is 13.4 kg, with dimensions of 300 mm × 200 mm × 200 mm, and the power consumption is 25 W. In this paper, the design of the ion source, mass analyzer, and detector is discussed in detail. The upper limit of the mass range is greater than 500 amu, and the best resolving power obtained so far on the miniature TOF MS is around 405 at full width half maximum (FWHM); other performance indexes of the instrument are also determined, where the worst case for mass stability is 0.49%, together with a mass accuracy of 0.12% and a sensitivity of 0.6 mV/ppm.Retallack, G.J., Conde, G.D., 2020. Deep time perspective on rising atmospheric CO2. Global and Planetary Change 189, 103177. accuracy of CO2 hindcasting using fossil Ginkgo stomatal index is ripe for revision for three reasons: exponential rise in atmospheric CO2 over the past decade, discovery of a Kew herbarium specimen of Ginkgo picked in 1754, and increased sophistication of a pedogenic CO2 paleobarometer as an independent parallel record. Past mass extinctions coincide with revised CO2 spikes of 1500 ppm or more. Increases such as the middle Miocene level of 640 ± 71 ppm expected before the year 2100 resulted in biome shifts, with expansion of tropical forests northward, and of grasslands into deserts. Deep time records from paleosols and from stomatal index reveal that CO2 levels less than 180 ppm and more than 1500 ppm are toxic to the biosphere.Riebe, M.E.I., Foustoukos, D.I., Alexander, C.M.O.D., Steele, A., Cody, G.D., Mysen, B.O., Nittler, L.R., 2020. The effects of atmospheric entry heating on organic matter in interplanetary dust particles and micrometeorites. Earth and Planetary Science Letters 540, 116266. dust particles (IDPs) and micrometeorites (MMs) were likely major sources of extraterrestrial organics at the surface of the early Earth. However, these particles experience heating to >500 °C for up to several seconds during atmospheric entry. In this study, we aim to understand the effects of atmospheric entry heating on the dominant organic component in IDPs and MMs by conducting flash heating experiments (4 s to 400 °C, 600 °C, 800 °C, and 1000 °C) on insoluble organic matter (IOM) extracted from the meteorite Cold Bokkeveld (CM2). For each of the experimental charges, the bulk isotopic compositions of H, N, and C were analyzed by IRMS, the H isotopic heterogeneities (occurrence of deuterium hotspots) of the samples were measured by NanoSIMS, and the functional group chemistry and ordering of the IOM was evaluated by using FTIR and Raman spectroscopy, respectively. Organic matter in particles heated to ≥600 °C during atmospheric entry experienced significant alteration. Loss of isotopically heavy, labile H and N groups results in decreases in bulk δD, δ15N, H/C and, upon heating ≥800 °C, in N/C. The H isotopic heterogeneity was not greatly affected by flash heating to ≤600 °C, although the hotspots tended to be less isotopically anomalous in the 600 °C sample than in the 400 °C sample. However, the hotspots all but disappeared in the 800 °C sample. Loss of C=O groups occurred at 800 °C. Based on the Raman G-band characteristics, the heating resulted in increased ordering of the polyaromatic component of the IOM.The data presented in this study show that all aspects of the composition of organic matter in IDPs and MMs are affected by atmospheric entry heating. Modelling and temperature estimates from stepwise release of He has shown that most IDPs and MMs are heated to >500 °C (Love and Brownlee, 1991; Nier and Schlutter, 1993; Joswiak et al., 2007), hence, atmospheric entry heating is expected to have altered the organic matter in most such particles.Rigo, M., Onoue, T., Tanner, L.H., Lucas, S.G., Godfrey, L., Katz, M.E., Zaffani, M., Grice, K., Cesar, J., Yamashita, D., Maron, M., Tackett, L.S., Campbell, H., Tateo, F., Concheri, G., Agnini, C., Chiari, M., Bertinelli, A., 2020. The Late Triassic extinction at the Norian/Rhaetian boundary: Biotic evidence and geochemical signature. Earth-Science Reviews 204, 103180. latest Triassic was an interval of prolonged biotic extinction culminating in the end-Triassic Extinction (ETE). The ETE is now associated with a perturbation of the global carbon cycle just before the end of the Triassic that has been attributed to the extensive volcanism of the Circum-Atlantic Magmatic Province (CAMP). However, we attribute the onset of declining latest Triassic diversity to an older perturbation of the carbon cycle (δ13Corg) of global extent at or very close to the Norian/Rhaetian boundary (NRB). The NRB appears to be the culmination of stepwise biotic turnovers that characterize the latest Triassic and includes global extinctions of significant marine and terrestrial fossil groups. These biotic events across the NRB have been largely under-appreciated, yet together with a coeval disturbance of the carbon cycle were pivotal in the history of the Late Triassic. Here, we present new and published δ13Corg data from widespread sections (Italy, Greece, ODP, Australia, New Zealand, USA, Canada). These sections document a previously unknown perturbation in the carbon cycle of global extent that spanned the NRB. The disturbance extended across the Panthalassa Ocean to both sides of the Pangaean supercontinent and is recorded in both the Northern and Southern Hemispheres. The onset of stepwise Late Triassic extinctions coincides with carbon perturbation (δ13Corg) at the NRB, indicating that a combination of climatic and environmental changes impacted the biota at a global scale. The NRB event may have been triggered either by gas emissions from the eruption of a large igneous province pre-dating the NRB, by a bolide impact of significant size or by some alternative source of greenhouse gas emissions. As yet, it has not been possible to clearly determine which of these trigger scenarios was responsible; the evidence is insufficient to decisively identify the causal mechanism and merits further study.Rocke, E., Cheung, S., Gebe, Z., Dames, N.R., Liu, H., Moloney, C.L., 2020. Marine microbial community composition during the upwelling season in the southern Benguela. Frontiers in Marine Science 7, 255. doi: 10.3389/fmars.2020.00255. microbial communities of the southern Benguela upwelling region were sampled quarterly through 1 year, with sampling for prokaryotes taking place in May, September, November and February, spanning the 2015–2016 upwelling season. Picoeukaryote samples were taken in November and February only. Community dynamics were assessed at stations both inside and outside a typical upwelling site. 16S and 18S rRNA amplicon results, respectively, revealed differences in both bacterioplankton and picoeukaryote communities in both space and time (season). There was a significant difference between sites in picoeukaryote community structure and diversity during the upwelling season in February, but not in November. Prokaryote community structure showed significant changes by water type as well as by sampling time or site. The parasitic dinoflagellate, Syndiniales, dominated February samples, and diatoms (Mediophyceae) mostly occurred in November samples, with nitrate driving community structure. Prokaryote results revealed presence of Nitrosopumillus, an ammonium oxidizer, offshore in February. Nitrospina sp., a nitrite oxidizer, was also present in September in hypoxic and deep water samples. This study reveals significant changes in community variability, leading to shifts within interspecies interactions in this region in response to upwelling events. This has far reaching implications with regard to biogeochemical cycling and ecosystem functioning at the microbial level.Rouillard, J., García-Ruiz, J.M., Kah, L., Gérard, E., Barrier, L., Nabhan, S., Gong, J., van Zuilen, M.A., 2020. Identifying microbial life in rocks: Insights from population morphometry. Geobiology 18, 282-305. identification of cellular life in the rock record is problematic, since microbial life forms, and particularly bacteria, lack sufficient morphologic complexity to be effectively distinguished from certain abiogenic features in rocks. Examples include organic pore-fillings, hydrocarbon-containing fluid inclusions, organic coatings on exfoliated crystals and biomimetic mineral aggregates (biomorphs). This has led to the interpretation and re-interpretation of individual microstructures in the rock record. The morphologic description of entire populations of microstructures, however, may provide support for distinguishing between preserved micro-organisms and abiogenic objects. Here, we present a statistical approach based on quantitative morphological description of populations of microstructures. Images of modern microbial populations were compared to images of two relevant types of abiogenic microstructures: interstitial spaces and silica?carbonate biomorphs. For the populations of these three systems, the size, circularity, and solidity of individual particles were calculated. Subsequently, the mean/SD, skewness, and kurtosis of the statistical distributions of these parameters were established. This allowed the qualitative and quantitative comparison of distributions in these three systems. In addition, the fractal dimension and lacunarity of the populations were determined. In total, 11 parameters, independent of absolute size or shape, were used to characterize each population of microstructures. Using discriminant analysis with parameter subsets, it was found that size and shape distributions are typically sufficient to discriminate populations of biologic and abiogenic microstructures. Analysis of ancient, yet unambiguously biologic, samples (1.0?Ga Angmaat Formation, Baffin Island, Canada) suggests that taphonomic effects can alter morphometric characteristics and complicate image analysis; therefore, a wider range of microfossil assemblages should be studied in the future before automated analyses can be developed. In general, however, it is clear from our results that there is great potential for morphometric descriptions of populations in the context of life recognition in rocks, either on Earth or on extraterrestrial bodies.Roy, C., Rameez, M.J., Haldar, P.K., Peketi, A., Mondal, N., Bakshi, U., Mapder, T., Pyne, P., Fernandes, S., Bhattacharya, S., Roy, R., Mandal, S., O’Neill, W.K., Mazumdar, A., Mukhopadhyay, S.K., Mukherjee, A., Chakraborty, R., Hallsworth, J.E., Ghosh, W., 2020. Microbiome and ecology of a hot spring-microbialite system on the Trans-Himalayan Plateau. Scientific Reports 10, 5917. is known about life in the boron-rich hot springs of Trans-Himalayas. Here, we explore the geomicrobiology of a 4438-m-high spring which emanates ~70?°C-water from a boratic microbialite called Shivlinga. Due to low atmospheric pressure, the vent-water is close to boiling point so can entropically destabilize biomacromolecular systems. Starting from the vent, Shivlinga’s geomicrobiology was revealed along the thermal gradients of an outflow-channel and a progressively-drying mineral matrix that has no running water; ecosystem constraints were then considered in relation to those of entropically comparable environments. The spring-water chemistry and sinter mineralogy were dominated by borates, sodium, thiosulfate, sulfate, sulfite, sulfide, bicarbonate, and other macromolecule-stabilizing (kosmotropic) substances. Microbial diversity was high along both of the hydrothermal gradients. Bacteria, Eukarya and Archaea constituted >98%, ~1% and <1% of Shivlinga’s microbiome, respectively. Temperature constrained the biodiversity at ~50?°C and ~60?°C, but not below 46?°C. Along each thermal gradient, in the vent-to-apron trajectory, communities were dominated by Aquificae/Deinococcus-Thermus, then Chlorobi/Chloroflexi/Cyanobacteria, and finally Bacteroidetes/Proteobacteria/Firmicutes. Interestingly, sites of >45?°C were inhabited by phylogenetic relatives of taxa for which laboratory growth is not known at >45?°C. Shivlinga’s geomicrobiology highlights the possibility that the system’s kosmotrope-dominated chemistry mitigates against the biomacromolecule-disordering effects of its thermal water.Ru, J., Huo, Y., Yang, Y., 2020. Microbial degradation and valorization of plastic wastes. Frontiers in Microbiology 11, 442. doi: 10.3389/fmicb.2020.00442. growing accumulation of plastic wastes has become a severe environmental and social issue. It is urgent to develop innovative approaches for the disposal of plastic wastes. In recent years, reports on biodegradation of synthetic plastics by microorganisms or enzymes have sprung up, and these offer a possibility to develop biological treatment technology for plastic wastes. In this review, we have comprehensively summarized the microorganisms and enzymes that are able to degrade a variety of generally used synthetic plastics, such as polyethylene (PE), polystyrene (PS), polypropylene (PP), polyvinyl chloride (PVC), polyurethane (PUR), and polyethylene terephthalate (PET). In addition, we have highlighted the microbial metabolic pathways for plastic depolymerization products and the current attempts toward utilization of such products as feedstocks for microbial production of chemicals with high value. Taken together, these findings will contribute to building a conception of bio-upcycling plastic wastes by connecting the biodegradation of plastic wastes to the biosynthesis of valuable chemicals in microorganisms. Last, but not least, we have discussed the challenges toward microbial degradation and valorization of plastic wastes.Russkikh, I.V., Strel’nikova, E.B., Serebrennikova, O.V., Voistinova, E.S., Kharanzhevskaya, Y.A., 2020. Identification of hydrocarbons in the waters of raised bogs in the southern taiga of Western Siberia. Geochemistry International 58, 447-455. composition and content of hydrocarbons (HCs) in the waters three raised bogs of the south taiga subzone of Western Siberia: the Bolshoe bog, Central bog, and Bakchar bog (which is part of the Great Vasyugan mire) were determined by IR spectrometry, fluorimetry, and chromatography–mass spectrometry. The waters of the bogs are demonstrated to contain hydrocarbons coming from peat deposits (and produced by plants) and pyrogenic hydrocarbons. The Bolshoe bog, which occurs near areas with oil-producing facilities, is the only one whose water contains oil hydrocarbons. The most representative HCs group is n-alkanes whose carbon preference index (CPI) is 4.9–9.2. Among alicyclic HCs, the highest concentrations were detected for triterpenes, with the dominance of taraxerene and neohop-13(18)-ene in the Bolshoe and Bakchar bogs and diploptene in the Central bog. Contamination with oil hydrocarbons, which are transferred by air from oil- and gas-producing facilities, was identified based on the presence of methyl-substituted polycyclic aromatic hydrocarbons (PAHs), steranes, hopanes, and cheilanthanes and by reduced CPI in the water of the Bolshoe bog. The effect of fires in 2016 is inferred from the ratios of unsubstituted PAHs.Sabrekov, A.F., Semenov, M.V., Terent’eva, I.E., Litti, Y.V., Il’yasov, D.V., Glagolev, M.V., 2020. The link between soil methane oxidation rate and abundance of methanotrophs estimated by quantitative PCR. Microbiology 89, 182-191. pmoA gene number is considered as a soil microbiological parameter indicating abundance and potential activity of methanotrophic bacteria. The efficiency of this parameter for prediction and modeling of the real soil methane consumption rates remains an open issue. In the current study rate of methane oxidation by soil at its ambient concentration and the number of the pmoA genes determined by quantitative polymerase chain reaction were compared. Soil samples were collected in May, July, and September 2018 in the middle taiga subzone forest ecosystems near Khanty-Mansiysk, Russia. Soil methane oxidation rate varied from 0.01 to 8 ng СН4/g dry weight per hour. The pmoA gene numbers per g of dry weight varied from 107 to 109. The correlation between these two parameters became smaller as the scale changed from the soil profile level to ecosystem and interseasonal levels. Methane oxidation rate increased significantly above the threshold methanotroph abundance of 2 × 108pmoA genes/g. Within the intervals below and above this threshold value, no significant changes in methane oxidation rate occurred while methanotroph abundance increased. Thus, quantification of methanotroph abundance alone is insufficient for assessment of methanotrophic activity in upland soils, and the effect of other factors should be considered.Samanta, B., Singh, M.B., Malani, A., 2020. Energetics and structural behavior of asphaltene molecules near mica surface: Molecular simulation study. Energy & Fuels 34, 4071-4083. deposition of high asphaltene-containing crude oil on mineral surfaces and pipelines is a technical as well as an economic problem in the oil industry. In enhanced oil recovery techniques, additives and emulsifiers are used to detach oil from the mineral surface. It requires detailed knowledge of the type of interaction taking place at the molecular level between the rock surface and the crude oil to target the most dominant interacting part for site-specific design of emulsifiers. In this work, we have studied energetics of saturate and asphaltene molecules of crude oil with mica mineral surfaces in the presence of dodecane solvent using molecular dynamics simulations. Five different types of asphaltene molecules (three island type and two archipelago type) containing one heteroatom (oxygen, nitrogen, and sulfur) were considered in this study. We have calculated the potential of mean force using an umbrella sampling technique. The adsorption free energy of saturate molecules is significantly lower compared to asphaltene molecules because of the presence of the heteroatom. Asphaltene molecules with a polar heteroatom (oxygen and nitrogen) interact with mica surface strongly as compared to asphaltene molecules with a nonpolar heteroatom (sulfur). The structural behavior of asphaltene molecules at the mica–oil interface is governed by the balance of enthalpic interactions between aromatic core atoms and the steric hindrance of aliphatic chain atoms with the mica surface. Asphaltene molecules with smaller aliphatic chains are arranged parallel to the mica surface. In contrast, those molecules which have more and bigger aliphatic chains were found to have their aromatic core tilted to the mica surface. This detailed information would be useful for designing better additives to displace heavy and residual oil from the rock surface.Sanchís, J., Jaén-Gil, A., Gago-Ferrero, P., Munthali, E., Farré, M.J., 2020. Characterization of organic matter by HRMS in surface waters: Effects of chlorination on molecular fingerprints and correlation with DBP formation potential. Water Research 176, 115743. order to understand and minimize the formation of halogenated disinfection by-products (DBPs), it is important to investigate how dissolved organic matter (DOM) contributes to their generation. In the present study, we analysed the DOM profile of water samples from the Barcelona catchment area by high resolution mass spectrometry (HRMS) and we studied the changes after chlorination. Chlorination produced significant changes in the DOM, decreased the average m/z and Kendrick mass defect (KMD) of their spectra and decreased the number and abundance of lignin-like features. The Van Krevelen (VK) fingerprint exhibited several noticeable changes, including the appearance of highly oxidized peaks in the tannin-like region (average O/C, 0.78?±?0.08), the appearance of features with low H/C and the disappearance of more than half of the lipids-like features. Up to 657 halogenated peaks were generated during sample chlorination, most of which in the condensed hydrocarbons-like and the lignin-like region of the VK diagram.Around 200 features were found to be strongly correlated (ρ?≥?0.795) to the formation potential of trihalomethanes (THMs) and 5 were correlated with the formation potential of haloacetonitrile (HANs). They all were plotted in the lignin fraction of the VK diagram, but both groups of features exhibited different nitrogen content: those features related to HANs FP had at least one nitrogen atoms in their structures, whilst those related to THMs did not.Sandfeld, T., Marzocchi, U., Petro, C., Schramm, A., Risgaard-Petersen, N., 2020. Electrogenic sulfide oxidation mediated by cable bacteria stimulates sulfate reduction in freshwater sediments. The ISME Journal 14, 1233-1246. bacteria are filamentous members of the Desulfobulbaceae family that oxidize sulfide with oxygen or nitrate by transferring electrons over centimeter distances in sediments. Recent studies show that freshwater sediments can support populations of cable bacteria at densities comparable to those found in marine environments. This is surprising since sulfide availability is presumably low in freshwater sediments due to sulfate limitation of sulfate reduction. Here we show that cable bacteria stimulate sulfate reduction in freshwater sediment through promotion of sulfate availability. Comparing experimental freshwater sediments with and without active cable bacteria, we observed a three- to tenfold increase in sulfate concentrations and a 4.5-fold increase in sulfate reduction rates when cable bacteria were present, while abundance and community composition of sulfate-reducing microorganisms (SRM) were unaffected. Correlation and ANCOVA analysis supported the hypothesis that the stimulation of sulfate reduction activity was due to relieve of the kinetic limitations of the SRM community through the elevated sulfate concentrations in sediments with cable bacteria activity. The elevated sulfate concentration was caused by cable bacteria-driven sulfide oxidation, by sulfate production from an indigenous sulfide pool, likely through cable bacteria-mediated dissolution and oxidation of iron sulfides, and by enhanced retention of sulfate, triggered by an electric field generated by the cable bacteria. Cable bacteria in freshwater sediments may thus be an integral component of a cryptic sulfur cycle and provide a mechanism for recycling of the scarce resource sulfate, stimulating sulfate reduction. It is possible that this stimulation has implication for methanogenesis and greenhouse gas emissions.Santos, J.C.d., Lopes, D.R.G., Da Silva, J.D., De Oliveira, M.D., Dias, R.S., Lima, H.S., De Sousa, M.P., De Paula, S.O., Silva, C.C.d., 2020. Diversity of sulfate-reducing prokaryotes in petroleum production water and oil samples. International Biodeterioration & Biodegradation 151, 104966. from oil reservoirs are associated with negative impacts on the oilfield, such as oil biodeterioration and biocorrosion of steel structures used for exploration, transportation and storage. The objectives of this study were to analyze the taxonomic and functional diversity in the production water and oil of two oil reservoirs, with emphasis on H2S producing bacteria. Total DNA from the microbial community was extracted, and the taxonomic and functional diversity was evaluated. The phyla Proteobacteria, Firmicutes and Euryarchaeota were the most abundant among the samples and contain the main sulfate-reducing species, such as Desulfovibrio alaskensis and Archeoglobus fulgidus. The production water and the oil were found to have taxonomic and functionally different microbial communities in the three communities, however correlation networks showed basically the same types of interconnected metabolism between the sulfidogenic microorganisms. This indicates the importance of understanding the microbial diversity and metabolic capacity of communities in these environments and trying to control harmful processes that may result in huge economic damage to the oil industry.Schaefer, B., Grice, K., Coolen, M.J.L., Summons, R.E., Cui, X., Bauersachs, T., Schwark, L., B?ttcher, M.E., Bralower, T.J., Lyons, S.L., Freeman, K.H., Cockell, C.S., Gulick, S.P.S., Morgan, J.V., Whalen, M.T., Lowery, C.M., Vajda, V., 2020. Microbial life in the nascent Chicxulub crater. Geology 48, 328-332. Chicxulub crater was formed by an asteroid impact at ca. 66 Ma. The impact is considered to have contributed to the end-Cretaceous mass extinction and reduced productivity in the world’s oceans due to a transient cessation of photosynthesis. Here, biomarker profiles extracted from crater core material reveal exceptional insights into the post-impact upheaval and rapid recovery of microbial life. In the immediate hours to days after the impact, ocean resurge flooded the crater and a subsequent tsunami delivered debris from the surrounding carbonate ramp. Deposited material, including biomarkers diagnostic for land plants, cyanobacteria, and photosynthetic sulfur bacteria, appears to have been mobilized by wave energy from coastal microbial mats. As that energy subsided, days to months later, blooms of unicellular cyanobacteria were fueled by terrigenous nutrients. Approximately 200 k.y. later, the nutrient supply waned and the basin returned to oligotrophic conditions, as evident from N2-fixing cyanobacteria biomarkers. At 1 m.y. after impact, the abundance of photosynthetic sulfur bacteria supported the development of water-column photic zone euxinia within the crater.Schmitz, R.A., Pol, A., Mohammadi, S.S., Hogendoorn, C., van Gelder, A.H., Jetten, M.S.M., Daumann, L.J., Op den Camp, H.J.M., 2020. The thermoacidophilic methanotroph Methylacidiphilum fumariolicum SolV oxidizes subatmospheric H2 with a high-affinity, membrane-associated [NiFe] hydrogenase. The ISME Journal 14, 1223-1232. trace amounts (0.53?ppmv) of atmospheric hydrogen gas (H2) can be utilized by microorganisms to persist during dormancy. This process is catalyzed by certain Actinobacteria, Acidobacteria, and Chloroflexi, and is estimated to convert 75?×?1012?g H2 annually, which is half of the total atmospheric H2. This rapid atmospheric H2 turnover is hypothesized to be catalyzed by high-affinity [NiFe] hydrogenases. However, apparent high-affinity H2 oxidation has only been shown in whole cells, rather than for the purified enzyme. Here, we show that the membrane-associated hydrogenase from the thermoacidophilic methanotroph Methylacidiphilum fumariolicum SolV possesses a high apparent affinity (Km(app)?=?140?nM) for H2 and that methanotrophs can oxidize subatmospheric H2. Our findings add to the evidence that the group 1h [NiFe] hydrogenase is accountable for atmospheric H2 oxidation and that it therefore could be a strong controlling factor in the global H2 cycle. We show that the isolated enzyme possesses a lower affinity (Km?=?300?nM) for H2 than the membrane-associated enzyme. Hence, the membrane association seems essential for a high affinity for H2. The enzyme is extremely thermostable and remains folded up to 95?°C. Strain SolV is the only known organism in which the group 1h [NiFe] hydrogenase is responsible for rapid growth on H2 as sole energy source as well as oxidation of subatmospheric H2. The ability to conserve energy from H2 could increase fitness of verrucomicrobial methanotrophs in geothermal ecosystems with varying CH4 fluxes. We propose that H2 oxidation can enhance growth of methanotrophs in aerated methane-driven ecosystems. Group 1h [NiFe] hydrogenases could therefore contribute to mitigation of global warming, since CH4 is an important and extremely potent greenhouse gas.Schoeny, H., Rampler, E., Hermann, G., Grienke, U., Rollinger, J.M., Koellensperger, G., 2020. Preparative supercritical fluid chromatography for lipid class fractionation—a novel strategy in high-resolution mass spectrometry based lipidomics. Analytical and Bioanalytical Chemistry 412, 2365-2374. this work, a lipidomics workflow based on offline semi-preparative lipid class-specific fractionation by supercritical fluid chromatography (SFC) followed by high-resolution mass spectrometry was introduced. The powerful SFC approach offered separation of a wide polarity range for lipids, enabled enrichment (up to 3 orders of magnitude) of lipids, selective fractionation of 14 lipid classes/subclasses, and increased dynamic range enabling in-depth characterization. A significantly increased coverage of low abundant lipids improving lipid identification by numbers and degree (species and molecular level) was obtained in Pichia pastoris when comparing high-resolution mass spectrometry based lipidomics with and without prior fractionation. Proof-of-principle experiments using a standard reference material (SRM 1950, NIST) for human plasma showed that the proposed strategy enabled quantitative lipidomics. Indeed, for 70 lipids, the consensus values available for this sample could be met. Thus, the novel workflow is ideally suited for lipid class-specific purification/isolation from milligram amounts of sample while not compromising on omics type of analysis (identification and quantification). Finally, compared with established fractionation/pre-concentration approaches, semi-preparative SFC is superior in terms of versatility, as it involved only volatile modifiers and salt additives facilitating any follow-up use such as qualitative or quantitate analysis or further purification down to the single lipid species level.Scholz, V.V., Meckenstock, R.U., Nielsen, L.P., Risgaard-Petersen, N., 2020. Cable bacteria reduce methane emissions from rice-vegetated soils. Nature Communications 11, 1878. is the second most important greenhouse gas after carbon dioxide and approximately 11% of the global anthropogenic methane emissions originate from rice fields. Sulfate amendment is a mitigation strategy to reduce methane emissions from rice fields because sulfate reducers and methanogens compete for the same substrates. Cable bacteria are filamentous bacteria known to increase sulfate levels via electrogenic sulfide oxidation. Here we show that one-time inoculation of rice-vegetated soil pots with cable bacteria increases the sulfate inventory 5-fold, which leads to the reduction of methane emissions by 93%, compared to control pots lacking cable bacteria. Promoting cable bacteria in rice fields by enrichment or sensible management may thus become a strategy to reduce anthropogenic methane emissions.Schroll, M., Keppler, F., Greule, M., Eckhardt, C., Zorn, H., Lenhart, K., 2020. The stable carbon isotope signature of methane produced by saprotrophic fungi. Biogeosciences Discussions 2020, 1-21. (CH4) is the most abundant organic compound in the atmosphere with emissions from many biotic and abiotic sources. Recent studies have shown that CH4 production occurs under aerobic conditions in eukaryotes such as plants, animals, algae and saprotrophic fungi. Saprotrophic fungi play an important role in nutrient recycling in terrestrial ecosystems by their ability to decompose plant litter. Even though the CH4 production by saprotrophic fungi has been reported, so far, no data for stable carbon isotope values of the emitted CH4 (δ13C-CH4 values) is available. In this study we measured the δ13C values of CH4 and carbon dioxide (δ13C-CO2 values) emitted by the two saprotrophic fungi Pleurotus sapidus and Laetiporus sulphureus cultivated on three different substrates pine wood, grass and corn, reflecting both C3 and C4 plants with distinguished bulk δ13C values. Applying keeling plots, we found that the δ13C source values of CH4 emitted from fungi cover a wide range from ?40 mUr to ?69 mUr depending on the growth substrate and fungal species. Whilst little apparent carbon isotopic fractionation (in the range of ?0.3 mUr to 4.6 mUr) was calculated for δ13C values of CO2 released from P. sapidus and L. sulphureus relative to the bulk δ13C values of the growth substrates, much larger carbon isotopic fractionations (ranging from ?22 mUr to ?42 mUr) were observed for the formation of CH4. Whilst the two fungal species showed similar δ13CH4 source values when grown on pine wood, δ13CH4 source values differed substantially between the two fungal species when grown on grass or corn. We found that δ13CH4 source values emitted by saprotrophic fungi are highly dependent on the fungal species and the metabolized substrate. They cover a broad range of δ13CH4 values and overlap with values reported for methanogenic archaea, thermogenic degradation of organic matter and other eukaryotes.Schuhmacher, M., Grasskamp, A.T., Barahtjan, P., Wagner, N., Lombardot, B., Schuhmacher, J.S., Sala, P., Lohmann, A., Henry, I., Shevchenko, A., Coskun, ?., Walter, A.M., Nadler, A., 2020. Live-cell lipid biochemistry reveals a role of diacylglycerol side-chain composition for cellular lipid dynamics and protein affinities. Proceedings of the National Academy of Sciences 117, 7729.: Every cell produces thousands of lipid species, but studying the function of individual lipids in living cells is almost impossible with existing methodologies. Addressing this experimental bottleneck, we developed a strategy to quantify dissociation constants for lipid–protein interactions and transmembrane flip-flop rates of native lipids in live-cell experiments. Using a combination of plasma membrane-specific photochemical probes and mathematical modeling, we demonstrate that, for diacylglycerols as a model lipid class, the inherent lipid structural diversity caused by variations in acyl chain composition determines lipid protein affinities and transbilayer kinetics. In fact, subtle chemical differences change these values by orders of magnitude. Our approach represents a generally applicable method for elucidating the biological function of single lipid species on subcellular scales.Abstract: Every cell produces thousands of distinct lipid species, but insight into how lipid chemical diversity contributes to biological signaling is lacking, particularly because of a scarcity of methods for quantitatively studying lipid function in living cells. Using the example of diacylglycerols, prominent second messengers, we here investigate whether lipid chemical diversity can provide a basis for cellular signal specification. We generated photo-caged lipid probes, which allow acute manipulation of distinct diacylglycerol species in the plasma membrane. Combining uncaging experiments with mathematical modeling, we were able to determine binding constants for diacylglycerol–protein interactions, and kinetic parameters for diacylglycerol transbilayer movement and turnover in quantitative live-cell experiments. Strikingly, we find that affinities and kinetics vary by orders of magnitude due to diacylglycerol side-chain composition. These differences are sufficient to explain differential recruitment of diacylglycerol binding proteins and, thus, differing downstream phosphorylation patterns. Our approach represents a generally applicable method for elucidating the biological function of single lipid species on subcellular scales in quantitative live-cell experiments.Schwartz-Narbonne, R., Schaeffer, P., Hopmans, E.C., Schenesse, M., Charlton, E.A., Jones, D.M., Sinninghe Damsté, J.S., Farhan Ul Haque, M., Jetten, M.S.M., Lengger, S.K., Murrell, J.C., Normand, P., Nuijten, G.H.L., Talbot, H.M., Rush, D., 2020. A unique bacteriohopanetetrol stereoisomer of marine anammox. Organic Geochemistry 143, 103994. ammonium oxidation (anammox) is a major process of bioavailable nitrogen removal from marine systems. Previously, a bacteriohopanetetrol (BHT) isomer, with unknown stereochemistry, eluting later than BHT when examined by high performance liquid chromatography (HPLC), was detected in ‘Ca. Scalindua profunda’ and proposed as a biomarker for anammox in marine paleo-environments. However, the utility of this BHT isomer as an anammox biomarker is hindered by the fact that four other, non-anammox, bacteria are also known to produce a late-eluting BHT stereoisomer. The stereochemistry in Acetobacter pasteurianus, Komagataeibacter xylinus and Frankia sp. was known to be 17β, 21β(H), 22R, 32R, 33R, 34R (BHT-34R). The stereochemistry of the late-eluting BHT in Methylocella palustris was unknown. To determine if marine anammox bacteria produce a unique BHT isomer, we studied the BHT distributions and stereochemistry of known BHT isomer producers and of previously unscreened marine (‘Ca. Scalindua brodeae’) and freshwater (‘Ca. Brocadia spp.’) anammox bacteria, using HPLC and gas chromatographiy (GC) analysis of acetylated BHTs and ultra high performance liquid chromatography (UHPLC)-high resolution mass spectrometry (HRMS) analysis of non-acetylated BHTs. The 34R stereochemistry was confirmed for the BHT isomers in Ca. Brocadia sp. and Methylocella palustris. However, ‘Ca. Scalindua spp.’ synthesises a stereochemically distinct BHT isomer, with still unconfirmed stereochemistry (BHT-x). Only GC analysis of acetylated BHT and UHPLC analysis of non-acetylated BHT distinguished between late-eluting BHT isomers. Acetylated BHT-x and BHT-34R co-elute when examined by HPLC. As BHT-x is currently only known to be produced by ‘Ca. Scalindua spp.’, it may be a biomarker for marine anammox.Semrau, J.D., DiSpirito, A.A., Obulisamy, P.K., Kang-Yun, C.S., 2020. Methanobactin from methanotrophs: genetics, structure, function and potential applications. FEMS Microbiology Letters 367, fnaa045. methane-oxidizing bacteria of the Alphaproteobacteria have been found to express a novel ribosomally synthesized post-translationally modified polypeptide (RiPP) termed methanobactin (MB). The primary function of MB in these microbes appears to be for copper uptake, but MB has been shown to have multiple capabilities, including oxidase, superoxide dismutase and hydrogen peroxide reductase activities, the ability to detoxify mercury species, as well as acting as an antimicrobial agent. Herein, we describe the diversity of known MBs as well as the genetics underlying MB biosynthesis. We further propose based on bioinformatics analyses that some methanotrophs may produce novel forms of MB that have yet to be characterized. We also discuss recent findings documenting that MBs play an important role in controlling copper availability to the broader microbial community, and as a result can strongly affect the activity of microbes that require copper for important enzymatic transformations, e.g. conversion of nitrous oxide to dinitrogen. Finally, we describe procedures for the detection/purification of MB, as well as potential medical and industrial applications of this intriguing RiPP.Serra-Mora, P., Herráez-Hernández, R., Campíns-Falcó, P., 2020. Bimodal copper oxide nanoparticles doped phase for the extraction of highly polar compounds by in-tube solid-phase microextraction coupled on-line to nano-liquid chromatography. Journal of Chromatography A 1617, 460819. obtained from tetraethyl orthosilicate (TEOS) and triethoxymethylsilane (MTEOS) have been functionalized with different metal and metal oxide nanoparticles (NPs), and used as coatings of extractive capillaries for the extraction of polar compounds by in-tube solid-phase microextraction (IT-SPME) coupled on-line to nano-liquid chromatography (nano-LC). The extraction capabilities of the new phases have been studied using several triazinic herbicides with log of octanol/water partition coefficients (Kow) ranging from -0.7 to 3.21 under reversed phase chromatographic conditions. Best extraction efficiencies for the most polar compounds (log Kow ≤ 2.3) were typically obtained with the CuO NPs doped phase. The TEOS-MTEOS polymer can be modified with two types of NPs in order to obtain extractive phases capable of interacting with compounds of a wide range of polarities; alternatively, two capillaries each with a different type of NPs can be combined in series with the same goal. Under the later approach the limits of detection (LODs) found for the tested herbicides were 0.02–1.5 ?g/L, and the precision expressed as relative standard deviation (RSD) varied from 2 to 10% (n = 3). The recoveries found in sea water samples ranged from 80 to 107%. In addition, the developed CuO NPs doped phase can be used in hydrophilic interaction chromatography (HILIC), which is the separation mode recommended for highly polar compounds. This has been illustrated using the amino acids tyrosine (log Kow = -2.26) and tryptophan (log Kow = -1.06) as model compounds, being their respective LOD 0.1 and 0.3 ?g/mL. Examples of application of the developed bimodal extractive phase to different environmental and waste waters are given in order to show its utility and versatility.?esták, J., Planeta, J., Kahle, V., 2020. Compact optical detector utilizing light emitting diodes, 50?nL L-shaped silica capillary cell and CCD spectrometer for simultaneous multi-wavelength monitoring of absorbance and fluorescence in microcolumn liquid chromatography. Analytica Chimica Acta 1112, 80-91. detection setup utilizing light emitting diodes (LEDs), 50?nL L-shaped silica capillary detection cell (L-cell), and low-cost CCD spectrometer is described in this work. Experimental configuration can be equipped with two different LEDs for absorbance measurement and other two LEDs for fluorescence excitation. This setup is capable of simultaneous multi-wavelength monitoring of absorbance and fluorescence when light produced by the individual LEDs and light emitted by the fluorescent analytes is resolved in the spectrum outputted by the CCD spectrometer. Effective optical path of the 0.25?μm I. D. L-cell is 1?mm. Absorbance baseline noise is 1 mAU due to use of low-cost and relatively noisy CCD spectrometer and LED drivers. Nevertheless, the setup can detect adenosine 5′-monophosphate down to micromolar concentration. Performance of fluorescence monitoring allows detection of 5·10?10?M fluorescein when 23?mW 470?nm LED is used for excitation. The dynamic range of absorbance and fluorescence measurement is 867:1 and 1622:1, respectively. Separation of test mixture (alkylbenzenes and polyaromatic hydrocarbons) demonstrate the effective use of the detector for simultaneous absorbance and fluorescence detection with 0.2?×?150?mm packed capillary column. The benefits of the setup are relative simplicity, compact design and the fact that it can be operated without any optical filters, slits, and extremely precise positioning of the optical elements.Shan, J., Ju, J., Zhang, W., Han, H., Zhou, T., Wang, Y., Yang, S., Cao, Y., 2020. Hydrocarbon accumulation patterns of salt crust covered biogenic gas reservoirs in the Sanhu Depression, Qaidam Basin. Natural Gas Industry B 7, 120-126. biogenic gas reservoirs are extensively developed in the Sanhu Depression of the Qaidam Basin, where the largest domestic biogenic gas production base has been built up. In recent years, however, the exploration of biogenic gas there encounters a variety of difficulties, such as the identification of true and false seismic abnormality, the determination of micro-relief structure and the identification and description of lithologic traps, which are the bottlenecks restricting its exploration breakthrough. In this paper, hydrocarbon accumulation patterns of biogenic gas were studied. Then, based on fine structure interpretation results, combined with laboratory experiments, the sealing capacity, distribution range, formation time and genesis of salt crust were discussed, and the salt crust covered hydrocarbon accumulation pattern of biogenic gas was put forward. Finally, combined with the conditions of source rocks and reservoirs, the exploration prospect of salt crust covered biogenic gas reservoirs was predicted. And the following research results were obtained. First, the Quaternary in the Sanhu Depression is composed of sandstone–mudstone interbeds of shore-shallow lake facies, with superior conditions of source rocks and reservoirs. Many source–reservoir–caprock assemblages are vertically formed. The biogenic gas has the characteristics of dynamic hydrocarbon accumulation, i.e., continuous migration, accumulation, diffusion and re-accumulation. Second, under the effect of Himalayan movement, the climate changes frequently and the salinity of the ancient lake is zoned in the Sanhu Depression. A freshwater area is formed at the inlet of the river in the south and a brine area is formed in the north. Under the influence of evaporation, the phreatic water in the north is salinized continuously, and a set of extensively distributed salt crust with steady thickness and a strong sealing capacity is formed at the eastern part of Lingjian fault. Third, the biogenic gas generated by dark mudstone of lacustrine facies in the depression center migrates laterally and vertically to Lingjian fault zone and gets accumulated under the sealing of salt crust. In conclusion, high-quality source rocks and reservoirs and the salt crust with a strong sealing capacity in the Sanhu Depression constitute a good spatial–temporal configuration relationship of source rocks, reservoirs and cap rocks, so salt crust covered biogenic gas reservoirs can be formed to provide abundant natural gas resources with a broad exploration prospect.Sharma, A., Singh, M.R., 2020. Multi-analytical investigation of the composition and binders used in the earthen support layer of fifth–fourteenth century CE painted fragments from Bezeklik, China. Studies in Conservation 65, 221-237., microstructure, and binding media of the decorative earthen plaster fragments from the Buddhist cave temple of Bezeklik (fifth?fourteenth century CE), China, were analyzed by X-ray fluorescence, X-ray diffraction, scanning electron microscopy with energy-dispersive X-ray analysis, Fourier-transform infrared spectroscopy, sieve analysis, and other methods. In addition, gas chromatography-mass spectrometry was used for identification of the organic adhesive found mixed in the earthen plaster. Studies indicated the presence of proteinaceous material, mainly beeswax, with animal glue, pine resin, and plant sterol mixed in the earthen plaster as the biopolymer. The organic additives improved the basic qualities of the mud by acting as stabilizers, hardeners, and water proofers. The loamy sand soil sourced for Bezeklik plasters shows low cohesion and disaggregation of grains occurred for want of clay-sized particles in the plaster. Due to frequent handling and transportation, the fragments are now showing distress in the form of loss of earthen support and paint layers. Based on the analytical findings, traditional binders such as sepiolite clay, slaked lime, and fish glue were introduced and fragments consolidated for display.Shen, Z., Zhou, L., Li, H., Lu, Z., Cai, J., 2020. Experimental and numerical study on the anisotropic and nonlinear gas flow behavior of a single coal fracture under loading. Energy & Fuels 34, 4230-4242. flow behavior of the coal fracture is one of the important factors that control the production of coal bed methane after hydraulic fracturing operation in a coal seam. In this paper, a gas flow test was conducted in the single coal fracture perpendicular to the bedding planes. The nonlinear flow behavior was studied by applying differing pressure gradients in the gas flow test. A numerical flow simulation was carried out to study the anisotropic flow behavior. The numerical simulation was based on matching of the experimental results and the digital fracture geometry reconstructed from surface laser scanning and a self-developed surface mate algorithm. Based on the experimental and numerical results, a coal fracture permeability model was proposed considering both nonlinear and anisotropic effects. The proposed model was used in a fictive field operation to reveal their effects on the well performance. According to this study, we found that (1) the permeability of the coal fracture has strong anisotropy which is mainly affected by the irregular contact shape; (2) the nonlinear flow effect was obtained after the Reynolds number exceeded 10; (3) both anisotropic and nonlinear effects are dependent on the loading stress; and (4) the anisotropic and nonlinear effects have a strong influence on the fluid flow under field-scale conditions that cannot be neglected when performing production prediction after the hydraulic fracturing operation.Shi, C., Cao, J., Luo, B., Hu, W., Tan, X., Tian, X., 2020. Major elements trace hydrocarbon sources in over-mature petroleum systems: Insights from the Sinian Sichuan Basin, China. Precambrian Research 343, 105726. hydrocarbon sources in over-mature petroleum systems is important and challenging. Here we present a pilot study using inorganic geochemistry to trace hydrocarbon sources in the giant natural gas accumulations within the Sinian (Neoproterozoic) Dengying Formation in the Sichuan Basin, SW China. We investigated the major elements (Ti, Al, Fe, Mn, Mg, Ca, Na, K, and P) as tracers of hydrocarbon sources for the first time. Our results show that the over-mature solid bitumen in the reservoirs contains parts per million amounts of major elements in addition to carbon (i.e., organic matter). Na and K in the bitumen occur mainly in the V–Ni porphyrin form. Al, Fe, and Mn are present in the Fe porphyrin form. The behavior of P is relatively complex, and it may reside mainly in a non-porphyrin organic form. The other elements (Ti, Mg, and Ca) may be present as emulsified “invisible” nano-minerals. The Mn/Fe ratio and ternary 10Mn–Fe–P diagram can be used for hydrocarbon–source rock correlations. Based on the proxies, it is suggested that the lower Cambrian Qiongzhusi Formation was the main source of hydrocarbons in the Dengying Formation. Our data suggest that inorganic geochemistry is an effective method for the study of over-mature hydrocarbons and complements traditional organic geochemical approaches.Shi, R., Liu, J., Wang, X., Elsworth, D., Liu, Z., Wei, M., Liu, X., Wang, Z., 2020. Experimental observations of heterogeneous strains inside a dual porosity sample under the influence of gas-sorption: A case study of fractured coal. International Journal of Coal Geology 223, 103450. “permeability equilibration time” is typically assumed in interpreting permeability measurements – indicating that equilibration has been reached and both sorption-induced changes in deformation and their impact on permeability evolution have ceased. However, for extremely low matrix permeability (tight) dual porosity rocks, this “permeability equilibration time” may easily exceed the time interval between two consecutive permeability measurements – invalidating the interpretation of a steady permeability if the non-steady state conditions are not correctly accommodated. This is especially important where pressure diffusion from fracture to matrix results in a non-monotonic and non-asymptotic approach to a steady permeability, but instead contains multiple stages, plateaus and permeability reversals. We validated this hypothesis through experiments and analysis. Experiments measured the non-monotonic and scale-dependent deformations of fracture and matrix and linked these directly to the dynamic evolution of reservoir permeability. These laboratory strain measurements were integrated with numerical analyses to explore how mass and stresses transferred between matrix and fracture and were coupled under conditions of constant confining pressure. Strain gauges were distributed to directly measure stress transfer between matrix and fracture and interrogated deformation at different scales and at different proximities to control fractures. The prismatic sample of coal was tested under freely expanding boundary conditions. Optical microscopy and X-ray CT imaging were used to define the fracture distribution throughout the sample with mercury intrusion (capillary) porosimetry (MICP) constraining the pore size distribution and enabling independent estimation of matrix permeability. A numerical model was built and verified by matching measured strains and then applying this to model the evolution coal permeability from initial to ultimate equilibrium. Both the experimental and numerical results show that the final equilibrium state (pressure, stress and mass contents) for the matrix system extends to months rather than hours and suggests that some current permeability data may therefore reflect a non-equilibrium permeability state. Results also show that during this non-equilibrium condition, the swelling of the matrix near the fracture will cause not only compaction and narrowing of the fracture, but also shrinkage of the matrix that is distant from the fracture under constant confining pressure condition. Both experimental and numerical results demonstrate that the evolution of non-equilibrium strain/permeability is determined by the matrix-fracture interactions, including sorption-induced swelling/shrinking, through transient stresses in matrix and fractures. And that these non-equilibrium stress transfers determine the dynamic permeability evolution during gas extraction (e.g., CH4) or injection (e.g., CO2) at reservoir scale for tight dual porosity rocks (e.g., coal and shale).Shimada, K., Nohchi, M., Yang, X., Sugiyama, T., Miura, K., Takami, A., Sato, K., Chen, X., Kato, S., Kajii, Y., Meng, F., Hatakeyama, S., 2020. Degradation of PAHs during long range transport based on simultaneous measurements at Tuoji Island, China, and at Fukue Island and Cape Hedo, Japan. Environmental Pollution 260, 113906. investigated the degradation of polycyclic aromatic hydrocarbons (PAHs) during long-range transport. Aerosols were collected simultaneously at remote sites on Tuoji Island, China; Fukue Island, Japan; and the Cape Hedo Atmosphere and Aerosol Measurement Station (CHAAMS), Okinawa, Japan in April, October, and December from 2012 to 2013. These remote sites were convenient for investigating the degradation of PAHs during long-range transport. PAHs were analyzed via gas chromatography/mass spectrometry. We identified air masses that passed over all sites and combined our measurements with a chemical transport model. We estimated the relative contributions of the PAHs at the three sites by normalizing the PAH concentrations to elemental carbon. Benzo[a]pyrene persisted in 5–16% of samples. The results of this study are consistent with laboratory studies in which secondary organic aerosol (SOA) coatings protected PAHs from degradation by ozone. We detected an inhibition of the degradation PAHs by SOA coatings by collecting PAHs simultaneously at the three sites. To elucidate the major sources of the SOAs, we carried out a positive matrix factorization analysis to identify the major sources of SOA coating, which controls the lifetime of PAHs. In spring and winter, the contribution of vehicle emissions was higher (46%) at Tuoji Island than at CHAAMS (13%). In contrast, the contribution of coal combustion was higher at CHAAMS (59%) than at Tuoji Island (28%). This result implies that during long-range transport, PAHs derived from coal combustion are more slowly degraded than PAHs derived from vehicle emissions. We found that the viscosity of SOA coatings derived from vehicle emissions in China was low, and the corresponding PAHs were rapidly degraded. In contrast, the viscosity of SOA coatings derived from coal combustion was high, and degradation of the corresponding PAHs was relatively slow. These results imply that PAHs derived from coal combustion have long lifetime.Shojaei, S.A., Osfouri, S., Azin, R., Mousavi Dehghani, S.A., 2020. Kinetic modeling of asphaltene nano-aggregates formation using dynamic light scattering technique. Journal of Petroleum Science and Engineering 192, 107293. is known as a class of polar poly-nuclear aromatic compounds of crude oil which is extracted by its solubility difference in normal heptane and toluene. Precipitation of this hydrocarbon compound by changing in fluid thermodynamic conditions decelerates flow when passing through up-stream and down-stream processes. In order to understand the thermodynamics of the deposition phenomenon, one needs to pay attention to the kinetics of the aggregation of these nano-particles. In this study, the kinetics phenomenon of aggregation of asphaltene clots in toluene is investigated using dynamic light scattering (DLS) technique. The dynamic light scattering results for super dilute solutions showed that at high and low sonication time, the asphaltene is monomeric and polymeric forms, respectively. Moreover, the experiments revealed that the relationship between the amount of sonication energy given to the solutions and the particle size is logarithmic. The DLS spectra obtained from the lower-sonication solutions were decomposed to the four normal distributions using the deconvolution technique, indicating four different clusters in the solution. The ratio of the area of each normal distribution to the area of the spectrum indicates the fraction of the presence of each cluster in the solution. For the lower and the higher concentrations of the asphaltene solution, the percentage of nano-aggregates is between 8%-41% and 4%–51%, respectively. By assuming the asphaltene molecule to be on a coin-shaped plate and forming a π bond with a minimal coinage overlap, the coin model of asphaltene aggregation kinetics has been developed. The concentration of each nano-aggregates in equilibrium solution is calculated according to the fraction of its presence in the medium and the coin model. Then, these equilibrium concentrations are used to calculate the equilibrium reaction constants. The correlation coefficient between the reaction constants and the diffusion coefficients of the clots in the solutions for all reactions was found to be equal to 0.42. This same value indicates that this coefficient is independent of the concentration of asphaltene in the solution and is dependent on the nature of the solution.Si, W., Hou, D., Wu, P., Zhao, Z., Ma, X., Zhou, H., Cao, L., 2020. Geochemical characteristics of Lower Cretaceous lacustrine organic matter in the southern sag of the Wuliyasitai depression, Erlian Basin, China. Marine and Petroleum Geology 118, 104404. Wuliyasitai southern sag is an oil-rich area in the Erlian Basin. The geochemical characteristics of the organic matter were comprehensively analyzed by a combined investigation of Rock-Eval pyrolysis, molecular geochemistry, vitrinite reflectance, and thin section observation. The studied samples have vitrinite reflectance (Ro) values of 0.33–1.22% and pyrolysis parameter Tmax values of 424–456 °C, suggesting that organic matter is mainly present in the low mature to mature stage. The values of the abundance indicators including total organic carbon (TOC), chloroform bitumen “A,” potential hydrocarbon generation amount (PG), hydrogen index (HI), and total hydrocarbon (HC) suggest a good to very good hydrocarbon generation potential. The pyrolysis parameter Tmax and HI obtained imply that the samples are dominated by the type Ⅱ1-Ⅱ2 organic matter. The composition characteristics of n-alkanes, steranes, and terpanes confirm that the organic matter has mixed input sources. The Aershan Formation (K1ba) in the southeastern part of the sag show higher contributions of algae and bacteria due to fertilization by volcanic ash. The hydrocarbon generation threshold was determined from the hydrocarbon index (HCI), production index (PI), chloroform bitumen “A"/TOC, and HC/TOC. By analyzing the relationships between TOC and pyrolysis parameter HCI, chloroform bitumen “A”/TOC, the lower limits of the TOC values for effective source rocks were established to be 2.5 wt % in the K1bt1 and 1.5 wt % in the K1ba. The pristane/phytane (Pr/Ph), gammacerane/C31 22R hopane, C35/C34 homohopane and trace element ratios suggest that the source rocks are primarily deposited in a freshwater sub-oxidizing environment. The TOC and HI are negatively correlated with Pr/Ph, indicating that redox conditions play an important role in source rock preservation. Most molecular maturity parameters are not recommended owing to their poor correlations with Ro.Sigmund, G., Gharasoo, M., Hüffer, T., Hofmann, T., 2020. Deep learning neural network approach for predicting the sorption of ionizable and polar organic pollutants to a wide range of carbonaceous materials. Environmental Science & Technology 54, 4583-4591. contaminants of emerging concern are polar and/or ionizable organic compounds, whose removal from engineered and environmental systems is difficult. Carbonaceous sorbents include activated carbon, biochar, fullerenes, and carbon nanotubes, with applications such as drinking water filtration, wastewater treatment, and contaminant remediation. Tools for predicting sorption of many emerging contaminants to these sorbents are lacking because existing models were developed for neutral compounds. A method to select the appropriate sorbent for a given contaminant based on the ability to predict sorption is required by researchers and practitioners alike. Here, we present a widely applicable deep learning neural network approach that excellently predicted the conventionally used Freundlich isotherm fitting parameters log KF and n (R2 > 0.98 for log KF, and R2 > 0.91 for n). The neural network models are based on parameters generally available for carbonaceous sorbents and/or parameters freely available from online databases. A freely accessible graphical user interface is provided.Simoncelli, A.P.P., Goméz, W., Charin, R.M., Fleming, F.P., Ndiaye, P.M., Tavares, F.W., 2020. Phase behavior of systems with high CO2 content: Experiments and thermodynamic modeling. Fluid Phase Equilibria 515, 112574. reservoirs are located in ultra-deep Brazilian waters. The petroleum production from these reservoirs is characterized by a high gas-oil ratio (GOR) and high content of CO2 in the associated gas. The challenges for production in such the pre-salt reservoir conditions include understanding the unusual phase behavior observed in the laboratory from field samples. In this paper, we discuss the phase equilibrium data and thermodynamic modeling of the systems containing CO2/n-C16H34, CH4/CO2/n-C16H34 and CH4/CO2/n-C16H34/C14H10. Transitions observed during this study were liquid-liquid (LL), vapor-liquid (VL), and vapor-liquid-liquid (VLL). The phase behavior investigated includes equilibrium conditions observed at temperatures from 293.1 K to 353.1 K and at pressures up to 58 MPa. The Peng-Robinson equation of state with classical van der Waals mixing rule was used to correlate the obtained experimental data. Results show a complex phase behavior for the binary system CO2/n-C16H34 at 298 K, featuring two liquid-liquid regions and barotropic inversion near the VLL transition. The addition of methane to the previous system (1/1 mol ratio relative to CO2) induces a phase behavior alteration in which the liquid-liquid transition disappears. The addition of a polyaromatic component (phenanthrene), whose influence over the mean molecular weight of the mixture under test is little, increased the saturation pressure. This study contributes to show that the use of a model representing the live-oil is a good strategy to understand how chemical and physical-chemical characteristics can induce complex phase behaviors, such as those observed in reservoirs with high carbon dioxide content.Singerling, S.A., Brearley, A.J., 2020. Altered primary iron sulfides in CM2 and CR2 carbonaceous chondrites: Insights into parent body processes. Meteoritics & Planetary Science 55, 496-523. presence of primary iron sulfides that appear to be aqueously altered in CM and CR carbonaceous chondrites provides the potential to study the effects and, by extension, the conditions of aqueous alteration. In this work, we have used SEM, TEM, and EPMA techniques to characterize primary sulfides that show evidence of secondary alteration. The alteration styles consist of primary pyrrhotite altering to secondary pentlandite (CMs only), magnetite (CMs and CRs), and phyllosilicates (CMs only) in grains that initially formed by crystallization from immiscible sulfide melts in chondrules (pyrrhotite‐pentlandite intergrowth [PPI] grains). Textural, microstructural, and compositional data from altered sulfides in a suite of CM and CR chondrites have been used to constrain the conditions of alteration of these grains and determine their alteration mechanisms. This work shows that the PPI grains exhibit two styles of alteration—one to form porous pyrrhotite‐pentlandite (3P) grains by dissolution of precursor PPI grain pyrrhotite and subsequent secondary pentlandite precipitation (CMs only), and the other to form the altered PPI grains by pseudomorphic replacement of primary pyrrhotite by magnetite (CMs and CRs) or phyllosilicates (CMs only). The range of alteration textures and products is the result of differences in conditions of alteration due to the role of microchemical environments and/or brecciation. Our observations show that primary sulfides are sensitive indicators of aqueous alteration processes in CM and CR chondrites.Singh, H., Myshakin, E.M., Seol, Y., 2020. A novel relative permeability model for gas and water flow in hydrate-bearing sediments with laboratory and field-scale application. Scientific Reports 10, 5697. a producing gas hydrate reservoir the effective porosity available for fluid flow constantly changes with dissociation of gas hydrate. Therefore, accurate prediction of relative permeability using legacy models (e.g. Brooks-Corey (B-C), van Genuchten, etc.) that were developed for conventional oil and gas reservoirs would require empirical parameters to be calibrated at various Sh over its range of variation, but such calibrations are precluded because of lack of experimental relative permeability data. This study proposes a new relative permeability model for gas hydrate-bearing media that is a function of maximum capillary pressure, capillary entry pressure, pore size distribution index, residual saturations, hydrate saturation, and four other constants. The three novel features of the proposed model are: (i) requires fitting its six empirical parameters only once using experimental data from any single Sh, and the same set of empirical parameters predict relative permeability at all Sh, (ii) includes the effect of capillarity, and (iii) includes the effect of pore-size distribution. From practical standpoint, the model can be used to simulate multiphase flow in gas hydrate-bearing sediments where the proposed relative permeability can account for the evolving hydrate saturation. The proposed model is implemented in a numerical simulator and the wall time required to perform simulations using the proposed model is shown to be similar to the time it takes to run same simulations with the B-C model. The proposed model is a step forward towards achieving the goal of physically accurate modeling of multiphase flow for gas hydrate-bearing sediments that accounts for the effect of gas hydrate saturation change on relative permeability.Skiba, S., Strukov, D., Sagidullin, A., Adamova, T., Stoporev, A., Svarovskaya, L., Strelets, L., Altunina, L., Manakov, A., 2020. Impact of biodegradation of oil on the kinetics of gas hydrate formation and decomposition. Journal of Petroleum Science and Engineering 192, 107211. the biological methods based on utilization of bacteria for different purposes in oilfields are becoming more and more popular because these methods potentially may become a cheaper alternative to chemical treatments. Gas hydrates formation in pipelines is the one of the main flow assurance problems. In previous works it has been shown that some biodegraded oils can have components that may act as natural Anti-Agglomerants. These natural Anti-Agglomerants can prevent hydrate particles from agglomeration which allow the particles to flow downstream along with oil in form of slurry. But there is lack of understanding of how products of oil biodegradation affect the kinetic aspects of hydrate nucleation, formation and decomposition. This information might be useful for development of new approached of treatment of the hydrate related issues in oil pipelines.Impact of the changes in component composition of crude oil caused by biodegradation process on the kinetics of gas hydrates nucleation, formation and decomposition has been studied with different methods. It was demonstrated that the changes of chemical composition of crude oil caused by biodegradation can have a strong impact on the hydrate nucleation rates at static conditions. Almost twofold decrease of hydrate nucleation rate was observed in the experiments with the water-in-oil emulsion for the biodegraded oils compared to one obtained with emulsion in the original crude oil. At the same time, no significant effect of biodegradation on the hydrate film growth rates at static conditions was observed. Similar tangential and normal hydrate film growth rates were obtained in experiments with both crude oil and with biodegraded oil. Initial growth rates of hydrate in stirring emulsions were an order of magnitude higher for water emulsions in the biodegraded oil compared to ones for the original crude oil. The studies of the decomposition rates of hydrates at sub-zero temperatures and at dynamic conditions showed that the products of vital activity of bacteria promoted self-preservation of hydrates dispersed in the biodegraded oil.Smets, T., Waelkens, E., De Moor, B., 2020. Prioritization of m/z-values in mass spectrometry imaging profiles obtained using uniform manifold approximation and projection for dimensionality reduction. Analytical Chemistry 92, 5240-5248. spectrometry imaging (MSI) is a promising technique to assess the spatial distribution of molecules in a tissue sample. Nonlinear dimensionality reduction methods such as Uniform Manifold Approximation and Projection (UMAP) can be very valuable for the visualization of the massive data sets produced by MSI. These visualizations can offer us good initial insights regarding the heterogeneity and variety of molecular patterns present in the data, but they do not discern which molecules might be driving these observations. To prioritize the m/z-values associated with these biochemical profiles, we apply a bidirectional dimensionality reduction approach taking into account both the spectral and spatial information. The results show that both sources of information are instrumental to get a more comprehensive view on the relevant m/z-values and can support the reliability of the results obtained using UMAP. We illustrate our approach on heterogeneous pancreas tissues obtained from healthy mice.?oltys, K., Plan?, M., Biocca, P., Vianello, V., Bu?ková, M., Pu?kárová, A., Sclocchi, M.C., Colaizzi, P., Bicchieri, M., Pangallo, D., Pinzari, F., 2020. Lead soaps formation and biodiversity in a XVIII Century wax seal coloured with minium. Environmental Microbiology 22, 1517-1534. multidisciplinary approach was carried out in order to study the biodeterioration and the associated microbiome of a XVIII Century wax seal coloured with minium. A small wax seal fragment was observed by scanning electron microscopy combined with energy dispersive spectroscopy in non‐destructive mode. The same object was analysed by Raman and Fourier‐transform infrared spectroscopy. The identification of the microbiota growing on the seal was performed with both a culture‐dependent strategy, combined with hydrolytic assays, and high‐throughput sequencing using the MinION platform. The whole bacterial 16S rRNA gene and the fungal markers ITS and 28S rRNA were targeted. It was observed that the carnauba wax coloured with lead tetroxide (minium) was covered by a biofilm consisting of a network of filaments and other structures of microbial origin. The culture‐dependent and culture‐independent investigations showed the presence of a complex microbiota composed mainly by fungal members, which demonstrated interesting properties related to lipids and lead processing. The formation of lead soaps and secondary biogenic minerals was also described.Song, M., Liu, H., Wang, Y., Liu, Y., 2020. Enrichment rules and exploration practices of Paleogene shale oil in Jiyang Depression, Bohai Bay Basin, China. Petroleum Exploration and Development 47, 242-253. on formation testing data of more than 40 wells with industrial oil flow, systematic observation of 1 010.26 m long cores taken from 4 wells and test data of over 10 000 core samples combining with drilling and pilot fracturing data of multiple wells, the geological characteristics of the upper submember of the Sha 4 Member to the lower submember of the Sha 3 Member of Paleogene (Es4s-Es3x) in the Jiyang Depression were investigated to find out factors controlling the enrichment of shale oil and the accumulation model of shale oil, and a comprehensive evaluation method for shale oil sweet spots was established. It is found through the study that the target shale layer is characterized by strong heterogeneity, weak diagenesis, low thermal evolution and high content of clay and carbonate minerals. Shale lithofacies, microcrack, thin interlayer and abnormal pressure are the main factors affecting enrichment and stable production of shale oil, the organic rich laminar shale has the best storage and oil-bearing capacity, microcrack network system improve the storage capacity and permeability of the shale, the thin interlayer is the main flow channel for stable shale oil production, and the abnormal high pressure layer is rich in free state shale oil and high in oil content. The shale oil layers in the target section were divided into three types: matrix, interlayer and fracture ones. According to the occurrence state and exploration practice of shale oil at home and abroad, it is concluded that the interlayer shale oil is the most profitable type at present. The selection parameters for the different types of shale oil were determined, and accordingly the favorable areas were pointed out by comprehensive evaluation of multiple factors. Vertical wells in the interlayer shale oil reservoir, such as Fan 159, Fan 143 and GX 26, were stimulated by volume fracturing and high conductivity channel fracturing jointly. After fracturing, they had a daily oil production of over 6 t, up to 44 t, and stable productivity. Shale oil is expected to become an important replacement energy resource in the Jiyang Depression.Song, T., Zheng, N., Liu, Y., Kuang, H., Peng, N., Li, C., Tang, J., Yan, Q., Gao, L., Zhu, Z., Xia, X., Wang, Y., 2020. Discovery of cosmic spherules from the Mesoproterozoic strata and its significance—in case of the Ming Tombs Area, Beijing. Acta Geologica Sinica - English Edition 94, 38-56. study covers cosmic spherules derived from the Mesoproterozoic Dahongyu Formation in the Ming Tombs area, Beijing. The cosmic spherules include iron oxide cosmic spherules, carbonaceous chondrites, and atomic iron “steely bead”‐shaped cosmic spherules. The mineral assemblage of silicon carbide, forsterite, zircon, and glass spherules and fragments were picked from melt‐silicified carbonate of the Mesoproterozoic Dahongyu Formation (ca. 1625 Ma). Cosmic spherule assemblages are solely discovered from sedimentary rocks in China. Platinum group elements (PGE) were determined for the first time in cosmic spherules and associated minerals. PGE comparative observation between meteorite and cosmic spherules is presented in this study. It is recognized that an extraterrestrial meteorite impact event might have occurred in the Dahongyu Stage. The main evidence is a large number of iron cosmic spherules in silicified oncolitic limestone, and associated cosmic silicon carbide, glass spherules, and fragments, as well as the presence of forsterite. The impact‐volcanic crater is characteristic of a big black shale block dropped into the bended silicified limestone.Soulgani, B.S., Reisi, F., Norouzi, F., 2020. Investigation into mechanisms and kinetics of asphaltene aggregation in toluene/n-hexane mixtures. Petroleum Science 17, 457-466. the rate of asphaltene particle growth is one of the main problems in modeling of asphaltene precipitation and deposition. In this paper, the kinetics of asphaltene aggregation under different precipitant concentrations have been studied. The image processing method was performed on the digital photographs that were taken by a microscope as a function of time to determine the asphaltene aggregation growth mechanisms. The results of image processing by MATLAB software revealed that the growth of asphaltene aggregates is strongly a function of time. Different regions could be recognized during asphaltene particle growth including reaction- and diffusion-limited aggregation followed by reaching the maximum asphaltene aggregate size and start of asphaltene settling and the final equilibrium. Modeling has been carried out to predict the growth of asphaltene particle size based on the fractal theory. General equations have been developed for kinetics of asphaltene aggregation for reaction-limited aggregation and diffusion-limited aggregation. The maximum size of asphaltene aggregates and settling time were modeled by using force balance, acting on asphaltene particles. Results of modeling show a good agreement between laboratory measurements and model calculations.Spiteri, C., Belser, M., Crispino, A., 2020. Preliminary results on content analysis of Early Bronze Age vessels from the site of Castelluccio, Noto, Sicily. Journal of Archaeological Science: Reports 31, 102355. study of vessel content can reveal important information about the dietary and culinary preferences of ancient communities. In this preliminary study, we analysed the absorbed lipid content of ten vessels from the settlement of Castelluccio in Sicily, dating to the Early Bronze Age (EBA). The vessels tested included a small selection of ceramic forms typically found in Bronze Age sites in Sicily, namely fine drinking wares and coarse ware vessels thought to have been used in food preparation and/or storage. All of the vessels tested were recovered from Hut 8. ORA results of this pilot project revealed challenging lipid preservation conditions known to occur in the Mediterranean region. Lipid analysis showed a possible animal contribution, although a plant input could not be excluded. Wine was not identified in the vessels tested.Sta?, M., Auersvald, M., Kejla, L., Vrti?ka, D., Kroufek, J., Kubi?ka, D., 2020. Quantitative analysis of pyrolysis bio-oils: A review. TrAC Trends in Analytical Chemistry 126, 115857. bio-oils are liquid products of lignocellulosic biomass pyrolysis. They have a highly promising potential to be widely used, after an appropriate upgrade, as advanced biofuels, or as a source of valuable oxygen-containing chemicals. The chemical composition of bio-oils is very complicated as they contain thousands of different, mostly oxygen-containing, compounds with a wide distribution of physical and chemical properties, and concentrations. Detailed knowledge of the bio-oil composition is crucial in order to optimize the pyrolysis processes and/or the subsequent bio-oil upgrading processes. The main challenge in bio-oil analytics is the identification and quantification of the individual compounds as well as the quantification of the total content of the compounds with the characteristic functional groups. In this review, we will discuss a state-of-the-art quantitative analysis of bio-oils and formulate strategies for obtaining in-depth information on the composition of the bio-oils and/or the products of their upgrading. Thermic, non-catalytic fast pyrolysis bio-oils and their hydrotreated analogues are of interest of this review. The emphasis will be placed on the quantification of the compounds with the key oxygen-containing functional groups present in the bio-oils including aldehydes, ketones, carboxylic acids, phenols, carbohydrates, etc. Also, methods for the quantification of the individual compounds will be presented. Hence, this overview and critical assessment of the quantitative methods can help the researchers to better understand the results obtained by these methods and formulate strategies and goals for further research. In addition, the knowledge presented in this review will serve as a reference to any scientist working with complex mixtures of oxygenates.Stilwell, J.D., Langendam, A., Mays, C., Sutherland, L.J.M., Arillo, A., Bickel, D.J., De Silva, W.T., Pentland, A.H., Roghi, G., Price, G.D., Cantrill, D.J., Quinney, A., Pe?alver, E., 2020. Amber from the Triassic to Paleogene of Australia and New Zealand as exceptional preservation of poorly known terrestrial ecosystems. Scientific Reports 10, 5703. Northern Hemisphere dominates our knowledge of Mesozoic and Cenozoic fossilized tree resin (amber) with few findings from the high southern paleolatitudes of Southern Pangea and Southern Gondwana. Here we report new Pangean and Gondwana amber occurrences dating from ~230 to 40 Ma from Australia (Late Triassic and Paleogene of Tasmania; Late Cretaceous Gippsland Basin in Victoria; Paleocene and late middle Eocene of Victoria) and New Zealand (Late Cretaceous Chatham Islands). The Paleogene, richly fossiliferous deposits contain significant and diverse inclusions of arthropods, plants and fungi. These austral discoveries open six new windows to different but crucial intervals of the Mesozoic and early Cenozoic, providing the earliest occurrence(s) of some taxa in the modern fauna and flora giving new insights into the ecology and evolution of polar and subpolar terrestrial ecosystems.Stockey, R.G., Cole, D.B., Planavsky, N.J., Loydell, D.K., Fr?da, J., Sperling, E.A., 2020. Persistent global marine euxinia in the early Silurian. Nature Communications 11, 1804. second pulse of the Late Ordovician mass extinction occurred around the Hirnantian-Rhuddanian boundary (~444?Ma) and has been correlated with expanded marine anoxia lasting into the earliest Silurian. Characterization of the Hirnantian ocean anoxic event has focused on the onset of anoxia, with global reconstructions based on carbonate δ238U modeling. However, there have been limited attempts to quantify uncertainty in metal isotope mass balance approaches. Here, we probabilistically evaluate coupled metal isotopes and sedimentary archives to increase constraint. We present iron speciation, metal concentration, δ98Mo and δ238U measurements of Rhuddanian black shales from the Murzuq Basin, Libya. We evaluate these data (and published carbonate δ238U data) with a coupled stochastic mass balance model. Combined statistical analysis of metal isotopes and sedimentary sinks provides uncertainty-bounded constraints on the intensity of Hirnantian-Rhuddanian euxinia. This work extends the duration of anoxia to >3 Myrs – notably longer than well-studied Mesozoic ocean anoxic events.Su, X., Chiles, E., Maimouni, S., Wondisford, F.E., Zong, W.-X., Song, C., 2020. In-source CID ramping and covariant ion analysis of hydrophilic interaction chromatography metabolomics. Analytical Chemistry 92, 4829-4837. large proportion of the complexity and redundancy of LC-MS metabolomics data comes from adduct formation. To reduce such redundancy, many tools have been developed to recognize and annotate adduct ions. These tools rely on predefined adduct lists that are generated empirically from reversed-phase LC-MS studies. In addition, hydrophilic interaction chromatography (HILIC) is gaining popularity in metabolomics studies due to its enhanced performance over other methods for polar compounds. HILIC methods typically use high concentrations of buffer salts to improve chromatographic performance. Therefore, it is necessary to analyze adduct formation in HILIC metabolomics. To this end, we developed covariant ion analysis (COVINA) to investigate metabolite adduct formation. Using this tool, we completely annotated 201 adduct and fragment ions from 10 metabolites. Many of the metabolite adduct ions were found to contain cluster ions corresponding to mobile phase additives. We further utilized COVINA to find the major ionized forms of metabolites. Our results show that for some metabolites, the adduct ion signals can be >200-fold higher than the signals from the deprotonated form, offering better sensitivity for targeted metabolomics analysis. Finally, we developed an in-source CID ramping (InCIDR) method to analyze the intensity changes of the adduct and fragment ions from metabolites. Our analysis demonstrates a promising method to distinguish the protonated and deprotonated ions of metabolites from the adduct and fragment ions.Sulaimon, A.A., De Castro, J.K.M., Vatsa, S., 2020. New correlations and deposition envelopes for predicting asphaltene stability in crude oils. Journal of Petroleum Science and Engineering 190, 106782. precipitation and deposition of asphaltene are among the most pressing issues in the petroleum industry. This flow assurance issue may cause formation damage in porous media, the plugging and coking of wellbore and production pipelines and difficulties in the refining process. Such events lead to additional operating costs for the company. Therefore, knowing the conditions at which asphaltene may precipitate and can be stable may enable its management. Existing models of asphaltene stability are dependent on saturate, aromatic, resin and asphaltene (SARA) analysis which can be very expensive and time-consuming. Therefore, using regression analysis as well as MATLAB curve fitting and optimization procedures, a new set of correlations and asphaltene stability envelops (ASEs) based on the newly developed Density-Based Asphaltene/Resin ratio (DBAR), Density-Based Saturate/Aromatic ratio (DBSAr) and the Density-Based Colloidal Instability Index (DBCII) all as functions of oil density have been developed to consistently predict asphaltene stability. The new criteria were developed for the correlations by considering the boundary between stable and unstable regions in their respective plots. The new envelopes showed 83% reliability by accurately predicting asphaltene stability in 24 (eight stable and 16 unstable samples) out of 29 (13 stable and 16 unstable) crude oil samples. The correlation coefficient (R2), average absolute relative error (AARE) and the root-mean-square error (RMSE) for the new DBAR correlation are 0.9456, 0.8357 and 0.1219 respectively. The DBSAr correlation resulted in R2 of 0.9437, AARE of 0.1860 and RMSE of 0.2450. For the DBCII, the statistical indicator results were 0.9639 for the R2, 0.1376 for the RMSE and 0.1038 for the AARE.Sun, C.-H., Zhu, M.-X., Ma, W.-W., Sun, Z.-L., Zhang, X.-R., Ding, K.-Y., Liu, S.-H., 2020. Examining bulk and iron-associated organic carbon through depth in margin sea sediments (China) under contrasting depositional settings: Chemical and NEXAFS spectral characterization. Journal of Marine Systems 207, 103344. sediments are the largest sink for organic carbon (OC) on Earth, and iron (Fe) oxides play an important role in stabilization of sedimentary OC. However, the roles of Fe oxides in OC stabilization during prolonged burial, for example, up to tens of thousands of years or more are still poorly constrained. In this study, we used traditional chemical extraction and near-edge X-ray absorption fine structure (NEXAFS) spectroscopic technique to characterize bulk OC and Fe-associated OC (Fe-OC) through depth in gravity cores collected from three sites near the Yangtze River Estuary (YRE), in the South Yellow Sea (SYS), and in the middle Okinawa Trough, which have contrasting depositional environments. Results show that depositional environments have exerted quite different influences on sources and burial of sedimentary OC, and thus on OC degradation during prolonged burial at the three sites. Reactive Fe (FeR) contents at the three sites are greatly influenced by sediment sources, the history of its transport, and its reworking intensity, with FeR contents near the highly dynamic YRE much higher than at the central SYS and the middle Okinawa Trough. The fractions of Fe-OC in total OC (fFe-OC) displayed no clear or consistent trends with depth or by site, probably due to the dual roles of Fe redox cycling in OC protection versus its oxidation. As indicated by the fFe-OC, reactive Fe plays a limited role in OC preservation in margin sea sediments of East China. A combination of NEXAFS spectra and isotopic compositions of bulk OC and Fe-OC indicates that main OC functionalities have not experienced differential alterations and/or no specific OC moieties have been selectively stabilized/released during prolonged burial in the three contrasting depositional environments.Sun, M., Zhao, J., Pan, Z., Hu, Q., Yu, B., Tan, Y., Sun, L., Bai, L., Wu, C., Blach, T.P., Zhang, Y., Zhang, C., Cheng, G., 2020. Pore characterization of shales: A review of small angle scattering technique. Journal of Natural Gas Science and Engineering 78, 103294. better evaluate the reservoir quality and optimize shale gas extraction, it is necessary to quantitatively characterize pore structure in shale reservoirs using complementary methods. Conventional tools that have been used extensively for pore characterization include gas physisorption, mercury injection capillary pressure (MICP), nuclear magnetic resonance (NMR). Small- and ultra-small-angle scattering (SAS and USAS) techniques use neutrons or X-ray beam to penetrate shales and obtain information on its pore structure by measuring the intensity of scattered radiation within a range of scattering angles. SAS and USAS measures total pores in a size range from 0.5?nm to 20?μm. The petrophysical parameters such as porosity, pore size distribution (PSD), fractal dimension, and pore connectivity of shale reservoirs can be obtained by analyzing the SAS/USAS data using recently established mythology. The difference in the results of porosity and PSD between the scattering technique and fluid intrusion or physisorption techniques can provide unique information on closed pores. As reported in the literature, contrast-matching small-angle neutron scattering (CM-SANS) experiments can effectively characterize the accessibility of pores to various fluids to assess the pore connectivity of shale reservoirs. Future perspectives of utilizing SAS/USAS techniques are also put forward in the review.Sun, X., Fan, D., Liu, M., Liao, H., Tian, Y., 2020. The fate of organic carbon burial in the river-dominated East China Sea: Evidence from sediment geochemical records of the last 70?years. Organic Geochemistry 143, 103999. accumulation of organic carbon (OC) in the sediments of river-dominated continental margins plays a critical role in the global carbon budget and is subject to human modification. However, the relationships between human activities in drainage basins and carbon burial in modern sediments are still poorly understood. Here, a well preserved sediment core from a mud zone in the East China Sea (ECS) was analyzed for isotopes (δ13Corg and δ15N), radioisotopes (210Pb and 137Cs), bulk organic carbon and nitrogen, sediment grain size, major elements, trace metals and chemical properties (pH and Eh), in order to reveal the fate of the OC buried in the studied shelf over the last 70?years. The results showed that the input of terrestrial organic matter (TOM) from the Yangtze River into the ECS declined by 15% between 1980 and 2005, in concomitance with decreasing terrestrial-derived Ca and Zr. These changes were mainly due to alterations in the sediment load and cultivated land, induced by river damming and soil conservation practices. The amount of marine organic matter (MOM) was strongly and positively correlated with chlorophyll a concentrations and the loads of dissolved inorganic nitrogen and phosphate. The discharge of riverine nutrients from artificial fertilizers seems to be one of the key factors influencing marine productivity. OC burial fluxes varied between 33.8 and 54.7?g C m?2 yr?1 and were primarily related to changes in the mass accumulation rates (MARs) and OC%. Notably, due to the construction of the Three Gorges Dam (TGD) in 2003, the input of eroded material from the downstream and subaqueous delta of the Yangtze River increased, profoundly altering the local hydrodynamics and sedimentary redox levels. These changes may, in turn, accelerate the degradation of sedimentary OC, preventing carbon deposition and preservation.Sun, X., Miao, L., Wu, L., 2020. Applicability and theoretical calculation of enzymatic calcium carbonate precipitation for sand improvement. Geomicrobiology Journal 37, 389-399. with microbially induced calcium carbonate precipitation, enzymatically induced carbonate precipitation is not restricted by microorganisms. Urea concentrations, calcium concentrations, temperature, pH, and reaction days were considered to identify the optimum conditions for sand solidifying tests. For comparison with laboratory tests, a revised equation for the rate of urea hydrolysis and a theoretical model were developed to calculate production rates of calcium carbonate and porosity along sand columns. The results showed that under the same temperature, initial pH, and solute concentration, the pH of leachate, and the strength of sand columns cured with calcium acetate were higher than those cured with calcium chloride. With large particle sizes (1.0–2.0?mm), pH values of leachate were significantly smaller, while the strengths of sand columns with full grading were higher. The revised formula for urea hydrolysis is suitable for the EICP reaction. The theoretically calculated distribution of calcium carbonate is consistent with experimentally obtained results. The one-dimensional mathematical model indicated that the eventual porosity of all sand columns increased slightly along the sand columns and the decreasing range of sand columns cured with calcium acetate was the largest. This study lays a foundation for the application of EICP technology in the future.Sun, Y., Liu, Y., Pan, J., Wang, F., Li, M., 2020. Perspectives on cultivation strategies of Archaea. Microbial Ecology 79, 770-784. have been recognized as a major domain of life since the 1970s and occupy a key position in the tree of life. Recent advances in culture-independent approaches have greatly accelerated the research son Archaea. However, many hypotheses concerning the diversity, physiology, and evolution of archaea are waiting to be?confirmed by culture-base experiments. Consequently, archaeal isolates are in great demand. On the other hand, traditional approaches of archaeal cultivation are rarely successful and require urgent improvement. Here, we review the current practices and applicable microbial cultivation techniques, to inform on potential strategies that could improve archaeal cultivation in the future. We first summarize the current knowledge on archaeal diversity, with an emphasis on cultivated and uncultivated lineages pertinent to future research. Possible causes for the low success rate of the current cultivation practices are then discussed to propose future improvements. Finally, innovative insights for archaeal cultivation are described, including (1) medium refinement for selective cultivation based on the genetic and transcriptional information; (2) consideration of the up-to-date archaeal culturing skills; and (3) application of multiple cultivation techniques, such as co-culture, direct interspecies electron transfer (DIET), single-cell isolation, high-throughput culturing (HTC), and simulation of the natural habitat. Improved cultivation efforts should allow successful isolation of as yet uncultured archaea, contributing to the much-needed physiological investigation of archaea.Sun, Y., Romantschuk, M., Bang-Andreasen, T., Rantalainen, A.-L., Sinkkonen, A., 2020. Nitrogen fertilizers stimulate desorption and biodegradation of gasoline aromatics in the soil from high Arctic permafrost active layer: A laboratory study. International Biodeterioration & Biodegradation 150, 104957. of gasoline contaminated soil from high Arctic permafrost active layer near the Zackenberg research station in Northeast Greenland was studied in 28 days in the laboratory at 10?°C, a relevant local summer temperature. Fates of gasoline aromatics were followed in two groups: monoaromatics and naphthalene homologs. The treatments were control, natural attenuation, and biostimulation with fertilizers inorganic NPK, urea, and methylene urea, respectively. No natural attenuation was observed. Among the fertilizers, only urea significantly decreased the total concentration under the initial level (by 47%) in 28 days. NPK and urea but not methylene urea enhanced the desorption and extractability of soil gasoline aromatics and bioremediation from day 7–28; more bioremediation was enhanced by urea. In the same period, NPK and urea did not differ in the biostimulation of monoaromatics while the bioremediation of naphthalene homologs was enhanced remarkably more by urea. Soil pH effect of fertilizers was also studied and showed dependence on temperature. Conclusively, urea showed superiority to NPK and methylene urea in biostimulation of gasoline aromatics in this study.Sun, Z., Ni, Y., Wang, Y., Wei, Z., Wu, B., Li, J., Fan, W., Wang, G., Li, Y., 2019. Experimental investigation of the effects of different types of fracturing fluids on the pore structure characteristics of shale reservoir rocks. Energy Exploration & Exploitation 38, 682-702. chemical and physical capabilities of shale can be altered by the interactions between fracturing fluid and shale formation, affecting the long-term reservoir productivity. To obtain information regarding how fracturing fluids with different components impact the pore structure, porosity and mineral compositions of shale reservoir rocks over time, two different types of commercial fracturing fluids (slick water and crosslinked gel) were used to react with the shales from Longmaxi Formation of Lower Silurian in the Sichuan Basin of South China. Experiments were conducted with various time intervals (1, 4 and 10?days) in a reactor at 50?MPa and 100°C, and then analytical methods including X-ray diffraction, low pressure nitrogen adsorption, field emission scanning electron microscopy and porosity measurement were used to examine the changes of mineralogical compositions, pore structure and porosity. The results demonstrated that the mineral compositions of shale samples were significantly changed after treatment with two different fracturing fluids for 4?days. The analysis of field emission scanning electron microscopy revealed that the carbonate minerals were dissolved and developed many dissolution pores after slick water treatment, while the crosslinked gel mainly caused the precipitation of carbonate minerals. After exposure to different fracturing fluids, the total pore volume and specific surface area decreased over time. Moreover, the fractal dimensions (D1 and D2) of shale showed an apparent decrease trend after treatment with two different fracturing fluids, indicating that the pore surface and structure become smooth and regular. The porosity of shale significantly decreased by 15.9% and 17.8%, respectively, after 10?days of slick water and crosslinked gel treatment. These results indicated that the injection of the two different types of fracturing fluids may negatively impact the shale gas production through reducing the nanopore structure and porosity of shale reservoir rocks.Sundberg, F.A., Karlstrom, K.E., Geyer, G., Foster, J.R., Hagadorn, J.W., Mohr, M.T., Schmitz, M.D., Dehler, C.M., Crossey, L.J., 2020. Asynchronous trilobite extinctions at the early to middle Cambrian transition. Geology 48, 441-445. appeared and diversified rapidly in the Cambrian, but it is debated as to whether their radiations and extinctions were globally synchronous or geographically restricted and diachronous. The end of the early Cambrian is a classic example—it has traditionally been defined by the extinction of olenellid and redlichiid trilobites and the appearance of paradoxidid trilobites. Here we integrate the global biostratigraphy of these three trilobite groups with high-precision tuff and tandem detrital zircon U-Pb age constraints to falsify prior models for global synchronicity of these events. For the first time, we demonstrate that olenellid trilobites in Laurentia went extinct at least 3 Ma after the first appearance of paradoxidids in Avalonia and West Gondwana (ca. 509 Ma). They also disappeared before the extinction of redlichiids and prior to the base of the Miaolingian at ca. 506 Ma in South China. This indicates that these three trilobite groups (paradoxidids, olenellids, and redlichiids) and their associated biotas overlapped in time for nearly 40% of Cambrian Epoch 2, Age 4. Implications of this chronological overlap are: (1) trilobite transitions were progressive and geographically mediated rather than globally synchronous; and (2) paleontological databases underestimate the diversity of the early Cambrian. This ～3 Ma diachroneity, at a critical time in the early evolution of animals, also impacts chemostratigraphic and paleoclimatic data sets that are tied to trilobite biostratigraphy and that collectively underpin our understanding of the Cambrian Earth system.Suzuki, Y., Yamashita, S., Kouduka, M., Ao, Y., Mukai, H., Mitsunobu, S., Kagi, H., D’Hondt, S., Inagaki, F., Morono, Y., Hoshino, T., Tomioka, N., Ito, M., 2020. Deep microbial proliferation at the basalt interface in 33.5–104 million-year-old oceanic crust. Communications Biology 3, 136. upper oceanic crust is mainly composed of basaltic lava that constitutes one of the largest habitable zones on Earth. However, the nature of deep microbial life in oceanic crust remains poorly understood, especially where old cold basaltic rock interacts with seawater beneath sediment. Here we show that microbial cells are densely concentrated in Fe-rich smectite on fracture surfaces and veins in 33.5- and 104-million-year-old (Ma) subseafloor basaltic rock. The Fe-rich smectite is locally enriched in organic carbon. Nanoscale solid characterizations reveal the organic carbon to be microbial cells within the Fe-rich smectite, with cell densities locally exceeding 1010 cells/cm3. Dominance of heterotrophic bacteria indicated by analyses of DNA sequences and lipids supports the importance of organic matter as carbon and energy sources in subseafloor basalt. Given the prominence of basaltic lava on Earth and Mars, microbial life could be habitable where subsurface basaltic rocks interact with liquid water.Tan, S., Helling, M.R., Basile, F., Li-Oakey, K.D., 2020. Systematic study of ionic liquids based coal extraction: Selectivity in extract molecular weights and targeted functional groups. Energy & Fuels 34, 4554-4564. liquids (ILs) are environmentally friendly solvents that have been used to extract valuable compounds from coal and biomass. In this work, eight methylimidazolium-based ionic liquids were selected based on their different capabilities of interactions with solutes. ζ-Potential characterization was used as a descriptor to reveal the type of interactions (e.g., hydrogen bonding, π–π interaction, and dispersion force) between the chosen ILs and coal particles. Consequently, the different interactions with certain strengths between the selected cations/anions and coal particles provide unprecedented selectivity of ILs in coal extraction. For aromatic-rich bituminous coal, the ILs associated with Cl– preferably extracted polycyclic aromatic hydrocarbons (PAHs). In contrast, for the same cations, BF4– and SbF6– anions did not show significant PAH extraction for bituminous coal. On the other hand, for oxygen-rich subbituminous coal, the fatty acids (FAs) with more than 20 carbon atoms were found to be rich in the extracts from the ILs associated with Cl–, whereas the same C4mim+ cation with BF4–, PF6–, and SbF6– anions extracted unique tricyclic diterpanes. As such, this study provides systematic experimental results demonstrating that ILs may be custom designed to extract targeted compounds from coal or other complex feedstock such as lignocellulosic biomass.Tang, Q., Pang, K., Yuan, X., Xiao, S., 2020. A one-billion-year-old multicellular chlorophyte. Nature Ecology & Evolution 4, 543–549. (representing a clade within the Viridiplantae and a sister group of the Streptophyta) probably dominated marine export bioproductivity and played a key role in facilitating ecosystem complexity before the Mesozoic diversification of phototrophic eukaryotes such as diatoms, coccolithophorans and dinoflagellates. Molecular clock and biomarker data indicate that chlorophytes diverged in the Mesoproterozoic or early Neoproterozoic, followed by their subsequent phylogenetic diversification, multicellular evolution and ecological expansion in the late Neoproterozoic and Palaeozoic. This model, however, has not been rigorously tested with palaeontological data because of the scarcity of Proterozoic chlorophyte fossils. Here we report abundant millimetre-sized, multicellular and morphologically differentiated macrofossils from rocks approximately 1,000?million years ago. These fossils are described as Proterocladus antiquus new species and are interpreted as benthic siphonocladalean chlorophytes, suggesting that chlorophytes acquired macroscopic size, multicellularity and cellular differentiation nearly a billion years ago, much earlier than previously thought.Tazikeh, S., Sayyad Amin, J., Zendehboudi, S., Dejam, M., Chatzis, I., 2020. Bi-fractal and bi-Gaussian theories to evaluate impact of polythiophene-coated Fe3O4 nanoparticles on asphaltene precipitation and surface topography. Fuel 272, 117535. of nanoparticles can effectively inhibit asphaltene precipitation. The present study aims to explore the role of polythiophene-coated Fe3O4 nanoparticles in both asphaltene precipitation and surface topography alteration. Topography information of the surface is obtained through employing atomic force microscopy (AFM) imaging technique. Fractal theory, Gaussian theory, and statistical parameters (e.g., skewness and kurtosis parameters) are used to analyze the surface topography in the presence and absence of nanoparticles. The mono-fractal theory does not adequately describe the irregularity of the surface. Thus, the bi-fractal approach is utilized for investigating the topography alteration of the glass substrate as a result of asphaltene precipitation in the presence and absence of nanoparticles in both light and heavy oil samples. In this theory, the asperity of the surface is divided into two categories: micro- and macro-asperity; the fractal dimensions are calculated for each surface separately. Also, this work employs the bi-Gaussian theory for the first time to study characteristics of a surface that consists of summits. The results of the bi-Gaussian theory are in acceptable agreement with those obtained using the bi-fractal theory. It is found that nanoparticles greatly affect the surface topography. The results also confirm that asphaltene can be adsorbed more on nanoparticles in heavy synthetic oil, compared to light synthetic oil. The fractal theory is more accurate than the bi-Gaussian and statistical approaches as the fractal theory considers all scales/dimensions while other methods take into account only the height of asperity. According to the modeling results, the nanoparticles have potential to considerably lower asphaltene precipitation. This study can provide useful guidelines/tips for inhibiting the wettability alteration of the surface upon asphaltene precipitation over production and transportation processes while using nanoparticles.Tega, D.U., Nascimento, H., Jara, J.L., Santos, J.M., Eberlin, M.N., 2020. A rapid and versatile method to determine methanol in biofuels and gasoline by ambient mass spectrometry using a V-EASI source. Energy & Fuels 34, 4595-4602. is an organic compound commonly used as a solvent in the synthesis of fuel for internal combustion engines. However, the adulteration of fuels (biofuels and gasoline) with methanol is commonly practiced throughout world, and regulations to control the content of methanol in these fuels have been imposed. Although methanol in fuels can be analyzed by numerous analytical techniques, the traditional methods have some disadvantages, such as interferences, incomplete reactions, and lengthy analysis. Thus, the present work proposes a rapid and versatile methanol determination method using a simple derivatization of the sample with nicotinoyl chloride and subsequent fast analysis by ambient mass spectrometry using venturi easy ambient sonic-spray ionization (V-EASI-MS), without preseparation, taking into account all parameters of linearity, limits of detection, quantification, accuracy, and precision based on ISO 5725. We were able to develop a powerful method to quantify methanol in fuels which can be used as an alternative method to detect adulteration by government agencies.Thaler, C., Katz, A., Bonifacie, M., Ménez, B., Ader, M., 2020. Oxygen isotope composition of waters recorded in carbonates in strong clumped and oxygen isotopic disequilibrium. Biogeosciences 17, 1731-1744. reconstructions, which are mainly retrieved from oxygen isotope (δ18O) and clumped isotope (Δ47) compositions of carbonate minerals, are compromised when carbonate precipitation occurs in isotopic disequilibrium. To date, knowledge of these common isotopic disequilibria, known as vital effects in biogenic carbonates, remains limited, and the potential information recorded by δ18O and Δ47 offsets from isotopic equilibrium values is largely overlooked. Additionally, in carbonates formed in isotopic equilibrium, the use of the carbonate δ18O signature as a paleothermometer relies on our knowledge of the paleowaters' δ18O value, which is often assumed. Here, we report the largest Δ47 offsets observed to date (as much as ?0.270?‰), measured on microbial carbonates that are strongly linked to carbonate δ18O offsets (?25?‰) from equilibrium. These offsets are likely both related to the microorganism metabolic activity and yield identical erroneous temperature reconstructions. Unexpectedly, we show that the δ18O value of the water in which carbonates precipitated, as well as the water–carbonate δ18O fractionation dependence on temperature at equilibrium, can be retrieved from these paired δ18O and Δ47 disequilibrium values measured in carbonates. The possibility to retrieve the δ18O value of paleowaters, sediments' interstitial waters or organisms' body water at the carbonate precipitation loci, even from carbonates formed in isotopic disequilibrium, opens long-awaited research avenues for both paleoenvironmental reconstructions and biomineralization studies.Thiagarajan, N., Crémière, A., Bl?ttler, C., Lepland, A., Kirsim?e, K., Higgins, J., Brunstad, H., Eiler, J., 2020. Stable and clumped isotope characterization of authigenic carbonates in methane cold seep environments. Geochimica et Cosmochimica Acta 279, 204-219. seep environments are characterized by methane-rich fluid migration and discharge at the seafloor. These environments are also intimately linked to microbial communities, which oxidize methane anaerobically, increase alkalinity and promote authigenic carbonate precipitation. We have analyzed a suite of methane-derived authigenic carbonate (MDAC) crusts from the North and Barents Sea using stable and clumped isotopes (δ13C, δ18O, δ44Ca, and Δ47) to characterize the sources of fluids as well as the environment of carbonate authigenesis. We additionally assess the potential of MDACs as a Δ47-based paleotemperature archive.The MDACs occur as three main textural-mineralogic types: micritic Mg-calcite cements, micritic aragonite cements and cavity filling aragonite cements. We find that micritic Mg-calcite cements have low δ13CVPDB values (?30 to ?47‰), high δ44CaSW values (?0.4 to ?0.8‰), and Δ47-temperatures (0–6?°C) consistent with shallow sub-seafloor precipitation in isotopic equilibrium. Micritic aragonite cements and cavity filling aragonite cements both have a wider range in δ13CVPDB values (?18 to ?58‰), lower δ44CaSW values (?0.8 to ?1.6‰) and a larger range in Δ47-based apparent temperatures (–2 – 25?°C) with samples displaying equilibrium and disequilibrium clumped isotope values.The range in apparent temperatures as well as δ44CaSW values seen in the aragonite MDACs suggest two kinetic processes: a kinetic isotope effect (KIE) due to the incomplete equilibration of carbon and oxygen isotopes among DIC species from the different sources of DIC (i.e., seawater, methane-sourced DIC and DIC residual to CO2 degassing or diffusion) and a KIE due to a fast, irreversible precipitation affecting the cations, particularly Ca, bound to carbonate mineral. Our results improve the understanding of kinetic effects on clumped isotope temperatures in MDACs and demonstrate how the multi-isotopic approach combined with textural-mineralogic criteria can be used to identify MDACs for accurate paleotemperature reconstructions.Tian, J., Xu, C., Li, X., Wang, W., Lin, W., 2019. Depositional environment and pore structure of mixed lithofacies shale of the Longmaxi Formation in the DM Block, the Southern Sichuan Basin, China. Energy Exploration & Exploitation 38, 629-653. the differences of pore characters between different mixed lithofacies shales is helpful for improving shale gas development efficiencies. In this study, the targeted Longmaxi shale (L1) of the Southern Sichuan Basin was selected as the research object. Two kinds of mixed lithofacies shale were identified by analyzing total organic carbon and X-ray diffraction results. The forming depositional environment of mixed lithofacies shale was researched by elements analyses. Pores in different mixed lithofacies shale were observed using field emission scanning electronic microscope. Low-field nuclear magnetic resonance and low-temperature nitrogen adsorption were conducted to analyze pore characters of different mixed lithofacies shale. The results showed that L1 were mainly composed of organic rich clay–siliceous mixed shales (OR-M-1) and organic extreme rich calcareous–siliceous mixed shales (OER-M-3). OR-M-1 and OER-M-3 were formed in high paleo-producing dysoxic–oxic seawater and anoxic waterbody, respectively. Micro-pore and meso-pore volumes of OER-M-3 were greater than those of OR-M-1 while macro-pore volume of OER-M-3 was lower than that of OR-M-1. Meso-pore surficial and structural complexities of OER-M-3 were greater than those of OR-M-1. OER-M-3 were greater in oil-wetting micro-pore structural complexities while lower in water-wetting micro-pore structural complexities, compared with OR-M-1. The inherent relationships between lithofacies type and sedimentary environment, total organic carbon, as well as pore characters, respectively, were quite close.Tian, T., Yang, P., Ren, Z., Fu, D., Zhou, S., Yang, F., Li, J., 2020. Hydrocarbon migration and accumulation in the Lower Cambrian to Neoproterozoic reservoirs in the Micangshan tectonic zone, China: New evidence of fluid inclusions. Energy Reports 6, 721-733. Lower Paleozoic reservoir in the Micangshan tectonic zone is a new shale gas exploration area with excellent potential. However, the hydrocarbon migration and accumulation histories of this reservoir have not been thoroughly elucidated and urgently require further research. Fluid inclusions offer a unique and useful method to test for hydrocarbon migration, accumulation, composition and timing. This study integrated the hydrocarbon charge history using fluid inclusions in the Lower Cambrian to Neoproterozoic reservoir from the Micangshan tectonic zone. This work involves the delineation and analysis of fluid inclusions using the petrography, spectroscopy and microthermometry of fluid inclusions. Based on the fluid inclusion analyses combined with reservoir thermal history, timing estimates and charge models of the hydrocarbons were obtained. The formation of natural gas was multifactorial in the Lower Cambrian to Neoproterozoic petroleum system, and the gas in the Niutitang (?1n) and Dengying (Z2d) reservoirs was mainly from oil cracking and dry gas, and gas in the Xiannvdong (?1x) and Canglangpu (?1c) reservoirs was abiogenic and formed in hydrothermal fluids by regional tectonothermal events. Three well-defined stages of hydrocarbon charge were identified in the petroleum system in the Micangshan tectonic zone. The stage of oil charge first began before the Early Permian (～277 Ma); the stage of gas charge from oil cracking occurred in the Late Triassic to Early Jurassic (212 Ma-198 Ma); and the stage of gas charge from dry gas occurred in the Middle Jurassic (173 Ma-166 Ma). The gas of mixed origin from the Niutitang reservoir was stored in the nanoscale pores as a self-reservoir, rather than as an effective gas source for the overlying reservoirs.Titaley, I.A., Eriksson, U., Larsson, M., 2020. Rapid extraction method of polycyclic aromatic compounds in soil using basic silica selective pressurized liquid extraction. Journal of Chromatography A 1618, 460896. chemical mixtures found in soils at contaminated sites typically includes polycyclic aromatic compounds (PACs), thus posing potential environmental and human health risks. Pressurized liquid extraction (PLE) followed by silica clean-up is one of the most often used extraction methods for PACs in soil. While silica clean-up provide satisfactory recovery of oxygenated polycyclic aromatic hydrocarbons (OPAHs), this technique provides limited recovery of azaarenes. In this work, we used PLE and in-cell clean up with basic silica to increase the recovery of OPAHs and azaarenes. The optimized selective pressurized liquid extraction (SPLE) method used 4?g basic silica, dichloromethane, 100% flush volume, 100 and 120?°C extraction temperatures, with two static cycles for each temperature, no rinse in between the two extractions, and 20 and 120?s purge for the first and second extraction temperature, respectively. The method was validated for a wide range of PAC groups, including OPAHs, azaarenes, alkylated PAHs, and sulfur heterocycles (SPACs), in total 87 PACs, using certified reference material and in comparison to the results from previous inter-laboratory data. Our SPLE method yielded results that are in agreement with certified values and inter-laboratory data from prior analysis. The SPLE method also yielded lower variation than the results from the inter-laboratory data for analysis of OPAH and azaarenes, suggesting better precision than previous methods. More importantly, the SPLE method increases sample analysis throughput as extra clean-up step is not necessary anymore. The SPLE method was then successfully applied to rapidly screen PACs in three soil samples.Torres, M.A., Kemeny, P.C., Lamb, M.P., Cole, T.L., Fischer, W.W., 2020. Long-term storage and age-biased export of fluvial organic carbon: Field evidence from West Iceland. Geochemistry, Geophysics, Geosystems 21, e2019GC008632. organic carbon (OC) plays an important role in the carbon cycle, but questions remain regarding the controls and timescale(s) over which atmospheric CO2 remains sequestered as particulate OC (POC). Motivated by observations that terrestrial POC is physically stored within soils and other shallow sedimentary deposits, we examined the role that sediment storage plays in the terrestrial OC cycle. Specifically, we tested the hypothesis that sediment storage impacts the age of terrestrial POC. We focused on the Efri Haukadalsá River catchment in Iceland as it lacks ancient sedimentary bedrock that would otherwise bias radiocarbon‐based determinations of POC storage duration by supplying pre‐aged “petrogenic” POC.Our radiocarbon measurements of riverine suspended sediments and deposits implicated millennial‐scale storage times. Comparison between the sample types (suspended and deposits) suggested an age offset between transported (suspended sediments) and stored (deposits) POC at the time of sampling, which is predicted by theory for the sediment age distribution in floodplains. We also observed that POC in suspended sediments is younger than the predicted mean storage duration generated from independent geomorphological data, which suggested an additional role for OC cycling. Consistent with this, we observed interparticle heterogeneity in the composition of POC by imaging our samples at the microscale using X‐ray absorption spectroscopy. Specifically, we found that particles within individual samples differed in their sulfur oxidation state, which is indicative of multiple origins and/or diagenetic histories. Altogether, our results support recent coupled sediment storage and OC cycling models and indicate that the physical drivers of sediment storage are important factors controlling the cadence of carbon cycling.Tortorella, S., Tiberi, P., Bowman, A.P., Claes, B.S.R., ??upáková, K., Heeren, R.M.A., Ellis, S.R., Cruciani, G., 2020. LipostarMSI: Comprehensive, vendor-neutral software for visualization, data analysis, and automated molecular identification in mass spectrometry imaging. Journal of the American Society for Mass Spectrometry 31, 155-163. Spectrometry Imaging (MSI) is an established and powerful MS technique that enables molecular mapping of tissues and cells finding widespread applications in academic, medical, and pharmaceutical industries. As both the applications and MSI technology have undergone rapid growth and improvement, the challenges associated both with analyzing large datasets and identifying the many detected molecular species have become apparent. The lack of readily available and comprehensive software covering all necessary data analysis steps has further compounded this challenge. To address this issue we developed LipostarMSI, comprehensive and vendor-neutral software for targeted and untargeted MSI data analysis. Through user-friendly implementation of image visualization and co-registration, univariate and multivariate image and spectral analysis, and for the first time, advanced lipid, metabolite, and drug metabolite (MetID) automated identification, LipostarMSI effectively streamlines biochemical interpretation of the data. Here, we introduce LipostarMSI and case studies demonstrating the versatility and many capabilities of the software.Tourte, M., Schaeffer, P., Grossi, V., Oger, P.M., 2020. Functionalized membrane domains: An ancestral feature of Archaea? Frontiers in Microbiology 11, 526. doi: 10.3389/fmicb.2020.00526. and Eukarya organize their plasma membrane spatially into domains of distinct functions. Due to the uniqueness of their lipids, membrane functionalization in Archaea remains a debated area. A novel membrane ultrastructure predicts that monolayer and bilayer domains would be laterally segregated in the hyperthermophilic archaeon Thermococcus barophilus. With very different physico-chemical parameters of the mono- and bilayer, each domain type would thus allow the docking of different membrane proteins and express different biological functions in the membrane. To estimate the ubiquity of this putative membrane ultrastructure in and out of the order Thermococcales, we re-analyzed the core lipid composition of all the Thermococcales type species and collected all the literature data available for isolated archaea. We show that all species of Thermococcales synthesize a mixture of diether bilayer forming and tetraether monolayer forming lipids, in various ratio from 10 to 80% diether in Pyrococcus horikoshii and Thermococcus gorgonarius, respectively. Since the domain formation prediction rests only on the coexistence of di- and tetraether lipids, we show that all Thermococcales have the ability for domain formation, i.e., differential functionalization of their membrane. Extrapolating this view to the whole Archaea domain, we show that almost all archaea also have the ability to synthesize di- and tetraether lipids, which supports the view that functionalized membrane domains may be shared between all Archaea. Hence domain formation and membrane compartmentalization may have predated the separation of the three domains of life and be essential for the cell cycle.Tripathi, N., Sahu, L.K., Singh, A., Yadav, R., Karati, K.K., 2020. High levels of isoprene in the marine boundary layer of the Arabian Sea during spring inter-monsoon: Role of phytoplankton blooms. ACS Earth and Space Chemistry 4, 583-590. Arabian Sea possesses an intense oxygen minimum zone because of high primary productivity. These important biogeochemical aspects of the Arabian Sea have led us to investigate air–sea exchanges over the region. The measurements of the isoprene mixing ratio in marine air and biological parameters in seawater were conducted during the inter-monsoon period of April–May 2017. The year 2017 was the second warmest year since 1880 for the global ocean with positive sea surface temperature (SST) anomalies over the Arabian Sea during the campaign. The overall variation of isoprene follows the distribution of chlorophyll-a (Chl-a) with lower (0.38 ± 0.14 ppbv) and higher (0.75 ± 0.17 ppbv) values over central and northern regions, respectively. The diurnal pattern of isoprene covaries with solar flux, equivalent potential temperature, and wind speed as the daytime mixing ratio was ～55% higher than its night-time value. Major enhancements (>0.6 ppbv) were associated with the blooms of Trichodesmium and Thalassiosira in oligotrophic conditions. High abundance of diatoms and cyanobacteria, intense solar flux, and high SST favored the production of isoprene from microbial sources. The estimated emission fluxes of isoprene were in the range of 1.5 × 107 to 1.2 × 108 molecules cm–2 s–1. Levels of isoprene in marine air and its emission fluxes were higher than the values reported for most of the other highly productive oceans. This study highlights implications of the “Arabian Sea Paradox” on regional atmospheric chemistry.Troina, G.C., Dehairs, F., Botta, S., Tullio, J.C.D., Elskens, M., Secchi, E.R., 2020. Zooplankton-based δ13C and δ15N isoscapes from the outer continental shelf and slope in the subtropical western South Atlantic. Deep Sea Research Part I: Oceanographic Research Papers 159, 103235. the patterns of stable carbon (δ13C) and nitrogen (δ15N) isotopes at the base of the food webs (baseline) is essential in ecological studies for assessing the feeding habits and migration patterns of marine predators. We analysed δ13C and δ15N in zooplankton samples collected in spring and autumn (2012–2015), along the south (SCM) and southeast (NCSM) Brazilian oceanic waters. An increase in δ13C from the shelf break towards the offshore was associated with the influence of continental water input and upwellings along the shelf break, which introduce 13C-depleted inorganic carbon to the surface, where it will be incorporated into the biological system through phytoplankton growth. An opposite trend was observed in δ15N, with higher values along the shelf break related to the intrusion of upwelled deep-water nutrients, contrasting with the oligotrophic offshore waters where N2 fixation takes place, resulting in primary and secondary production that is relatively more depleted in 15N. A latitudinal (north-south) decrease in δ13C along the offshore area coincided with known isotopic patterns in inorganic carbon, which were more 13C-depleted towards higher latitudes. On the other hand, an increase in δ15N was observed towards the south, reflecting the contrast between the N2 fixation in the more oligotrophic waters in the NCSM and the higher nutrient availability in the SCM. Additionally, δ13C was significantly higher in autumn and δ15N was higher in spring. Although inter-annual differences in δ15N were non-significant, δ13C was significantly lower in 2012 than in the later years. This study provides novel information regarding the patterns of baseline δ13C and δ15N in the southwestern Atlantic Ocean, which will be useful for future investigation of the ecology of higher trophic-level organisms occurring in this area.Tu, J., Sheng, J.J., 2020. Effect of pressure on imbibition in shale oil reservoirs with wettability considered. Energy & Fuels 34, 4260-4272. studies indicate that there is a great potential for enhanced oil recovery in shale oil reservoirs by altering the matrix wetness to induce spontaneous imbibition. The most common method is to add surfactant additives in fracturing fluid during multistage hydraulic fracturing operation. This imbibition process has complex pressure systems involved such as reservoir pore pressure, wellbore hydrostatic pressure, and surface pumping pressure. Without the wells being soaked intentionally, this pressurized state may be sustained for more than a month before flowback. Therefore, it is important to study the effect of pressure on the imbibition-induced oil recovery enhancement and its mechanism. In this study, we conducted forced imbibition tests on core plugs of unconventional sandstone, carbonate, and shale with different wettabilities. The applied pressures were 1000, 2000, 3000, 4000, and 5000 psi, and the results were compared to those of spontaneous imbibition under atmospheric pressure. Experimental results were used further in the numerical simulation study. The results manifested that a more water-wet state is still essential to improve the oil recovery regardless of the soaking pressure. When the rock is oil-wet, higher soaking pressure does not further worsen imbibition because of the minimal negative capillary pressure when oil saturation is high. However, when the rock is water-wet, the soaking pressures can be adverse to the imbibition in shale formations because of a longer pressure transient time which is against the capillary force. Dimensionless pressure (pD) is defined in this study to quantitatively determine the extent of imbibition inhibition during the forced imbibition. This observation indicated that in tight reservoirs, a higher soaking pressure will obtain less oil recovery from imbibition than that of lower soaking pressure cases at a given time.Uahengo, C.-I., Shi, X., Jiang, G., Vatuva, A., 2020. Transient shallow-ocean oxidation associated with the late Ediacaran Nama skeletal fauna: Evidence from iodine contents of the Lower Nama Group, southern Namibia. Precambrian Research 343, 105732. terminal Ediacaran interval from ~ 550 Ma to 541 Ma witnessed the first appearance of skeletal metazoans and complex ecosystems in Earth history. This biotic innovation event is thought to be related to increase of oxygen in Earth’s surface environments, but many studies suggested that pervasive oceanic anoxia continued through the late Ediacaran and early Cambrian. To further evaluate the redox conditions of the terminal Ediacaran interval and their potential relationship with biotic changes, we analyzed the iodine contents in the Lower Nama Group (~550–547 Ma) from the Driedoornvlagte and Zebra River sections, southern Namibia. The I/[Ca + Mg] values fluctuate from 0.08 to 6.20 μmol/mol, with an average of 0.94 μmol/mol in the Driedoornvlagte section and 0.70 μmol/mol in the Zebra River section. High I/[Ca + Mg] values (>2.6 ?mol/mol) occur immediately above the boundary between the lower and upper Omkyk Members, with a peak up to 6.20 μmol/mol indicative of well-oxygenated surface waters comparable with those of the modern marine environments. Abundant skeletal fossils including Cloudina, Namacalathus, Namapoikia and trace fossils are observed only in the intervals after the high I/[Ca + Mg] peak. The results are consistent with the interpretation that the Nama skeletal communities grew in oxic (O2 > 20–70 μM) and dysoxic (O2 ≥ 10 μM) waters above the chemocline. The I/[Ca + Mg] ratios show significant tempo-spatial variations, which is also consistent with previous studies that suggested redox-stratified terminal Ediacaran sedimentary basins and highly heterogeneous oceanic redox conditions.Ullmann, C.V., Boyle, R., Duarte, L.V., Hesselbo, S.P., Kasemann, S.A., Klein, T., Lenton, T.M., Piazza, V., Aberhan, M., 2020. Warm afterglow from the Toarcian Oceanic Anoxic Event drives the success of deep-adapted brachiopods. Scientific Reports 10, 6549. aspects of the supposed hyperthermal Toarcian Oceanic Anoxic Event (T-OAE, Early Jurassic, c. 182?Ma) are well understood but a lack of robust palaeotemperature data severely limits reconstruction of the processes that drove the T-OAE and associated environmental and biotic changes. New oxygen isotope data from calcite shells of the benthic fauna suggest that bottom water temperatures in the western Tethys were elevated by c. 3.5?°C through the entire T-OAE. Modelling supports the idea that widespread marine anoxia was induced by a greenhouse-driven weathering pulse, and is compatible with the OAE duration being extended by limitation of the global silicate weathering flux. In the western Tethys Ocean, the later part of the T-OAE is characterized by abundant occurrences of the brachiopod Soaresirhynchia, which exhibits characteristics of slow-growing, deep sea brachiopods. The unlikely success of Soaresirhynchia in a hyperthermal event is attributed here to low metabolic rate, which put it at an advantage over other species from shallow epicontinental environments with higher metabolic demand.Umar, B.A., Gholami, R., Nayak, P., Shah, A.A., Adamu, H., 2020. Regional and field assessments of potentials for geological storage of CO2: A case study of the Niger Delta Basin, Nigeria. Journal of Natural Gas Science and Engineering 77, 103195. Niger Delta, as an actively producing oil and gas region has potential to develop into a new CO2 geological storage hub. Criteria for screening basins for Carbon Capture and Storage (CCS) was used in combination with 3D seismic data and well information to assess the basin's potential in this contribution. It is shown here that the presence of excellent reservoir-seal pair, very large basin size, suitable reservoir depth, matured oil and gas fields, moderate faulting intensity, availability of giant hydrocarbon fields and being a passive margin generally makes the Niger Delta basin excellent environment for CCS. High resolution 3D seismic dataset and well information from case study areas enabled identification of potential reservoir, traps and seals. Geomechanical analyses have shown that slip tendency is generally low while fracture stability is high, which indicates that the study area is stable in the current stress regime.Valenzuela, E.I., Padilla-Loma, C., Gómez-Hernández, N., López-Lozano, N.E., Casas-Flores, S., Cervantes, F.J., 2020. Humic substances mediate anaerobic methane oxidation linked to nitrous oxide reduction in wetland sediments. Frontiers in Microbiology 11, 587. doi: 10.3389/fmicb.2020.00587. substances are redox-active organic molecules, which play pivotal roles in several biogeochemical cycles due to their electron-transferring capacity involving multiple abiotic and microbial transformations. Based on the redox properties of humic substances, and the metabolic capabilities of microorganisms to reduce and oxidize them, we hypothesized that they could mediate the anaerobic oxidation of methane (AOM) coupled to the reduction of nitrous oxide (N2O) in wetland sediments. This study provides several lines of evidence indicating the coupling between AOM and the reduction of N2O through an extracellular electron transfer mechanism mediated by the redox active functional groups in humic substances (e.g., quinones). We found that the microbiota of a sediment collected from the Sisal wetland (Yucatán Peninsula, southeastern Mexico) was able to reduce N2O (4.6 ± 0.5 μmol N2O g sed.–1 day–1) when reduced humic substances were provided as electron donor in a close stoichiometric relationship. Furthermore, a microbial enrichment derived from the wetland sediment achieved simultaneous 13CH4 oxidation (1.3 ± 0.1 μmol 13CO2 g sed.–1 day–1) and N2O reduction (25.2 ± 0.5 μmol N2O g sed.–1 day–1), which was significantly dependent on the presence of humic substances as an extracellular electron shuttle. Taxonomic characterization based on 16S rRNA gene sequencing revealed Acinetobacter (a ?-proteobacterium), the Rice Cluster I from the Methanocellaceae and an uncultured archaeon from the Methanomicrobiaceae family as the microbes potentially involved in AOM linked to N2O reduction mediated by humic substances. The findings reported here suggest that humic substances might play an important role to prevent the emission of greenhouse gases (CH4 and N2O) from wetland sediments. Further efforts to evaluate the feasibility of this novel mechanism under the natural conditions prevailing in ecosystems must be considered in future studies.van de L?cht, J., Hoffmann, J.E., Rosing, M.T., Sprung, P., Münker, C., 2020. Preservation of Eoarchean mantle processes in ～3.8?Ga peridotite enclaves in the Itsaq Gneiss Complex, southern West Greenland. Geochimica et Cosmochimica Acta 280, 1-25. mantle and mantle-derived rocks can provide primary information on geodynamic processes operating on the early Earth. This study combines new petrological observations, comprehensive major and trace element data as well as Lu-Hf and Sm-Nd isotope compositions of >3.81?Ga ultramafic rocks from the Itsaq Gneiss Complex (IGC) in southern West Greenland. The sample set includes mantle peridotites and associated amphibolites from the Narssaq ultramafic body (F?ringehavn terrane) and from the region south of the Isua supracrustal belt (Isukasia terrane).Lutetium-Hf whole rock age regression lines mainly yield Eoarchean ages of ca. 3.9–3.8?Ga, in good agreement with minimum ages inferred from field relationships (>3.8?Ga). Major and trace element signatures, the Lu-Hf isotope inventory as well as most major elements, MREE, HREE, and HFSE were only slightly disturbed during metamorphic overprint. Nearly flat primitive mantle-normalized REE patterns obtained for the mantle peridotites resemble those of refertilized modern abyssal peridotites and may reflect re-enrichment of initially depleted peridotite by melt-like subduction components, as also indicated by Th-HFSE-REE characteristics. Based on a simple evolution-model for the investigated mantle rocks, we suggest that the compositions are best explained by partial hydrous melt depletion in the spinel stability field, followed by refertilization by low quantities of adakite-like melt. Altogether, the geochemical data can be put in the framework of a geodynamic model, where Eoarchean mantle underwent significant melt extraction and subsequent re-fertilization by subduction-like components. Based on this finding, we propose that the Eoarchean mantle peridotites from SW Greenland represent remnants of a mantle wedge, confirming that subduction-like processes were in operation since at least the Eoarchean.van der Boon, A., Kuiper, K.F., van der Ploeg, R., Cramwinckel, M.J., Honarmand, M., Sluijs, A., Krijgsman, W., 2020. Exploring a link between the Middle Eocene Climatic Optimum and Neotethys continental arc flare-up. Climate of the Past Discussions 2020, 1-15. Middle Eocene Climatic Optimum (MECO), a ~500?kyr episode of global warming that initiated at ~40.5?Ma, is postulated to be driven by a net increase in volcanic carbon input, but a direct source has not been identified. Here we show, based on new and previously published radiometric ages of volcanic rocks, that the interval spanning the MECO corresponds to a massive increase in continental arc volcanism in Iran and Azerbaijan. Ages of Eocene extrusive volcanic rocks in all volcanic provinces in Iran cluster around 40?Ma, very close to the peak warming phase of the MECO. Based on the spatial extent and volume of the volcanic rocks as well as the carbonaceous lithology in which they are emplaced, we estimate the total amount of CO2 that could have been released at this time corresponds to between 1500 and 11?300?Pg carbon. This is compatible with the estimated carbon release during the MECO. Although the uncertainty in both individual ages, and the spread in the compilation of ages, is larger than the duration of the MECO, a flare-up in Neotethys subduction zone volcanism represents a plausible excess carbon source responsible for MECO warming.Vega-Ortiz, C., Beti, D.R., Setoyama, E., McLennan, J.D., Ring, T.A., Levey, R., Martínez-Romero, N., 2020. Source rock evaluation in the central-western flank of the Tampico Misantla Basin, Mexico. Journal of South American Earth Sciences 100, 102552. rock evaluation is performed in a prospective block on the western-central flank of the Tampico Misantla Basin (TMB), Mexico, analyzing the Agua Nueva, Pimienta and Taman formations. The rock samples are drilling cores and cuttings obtained from legacy wells in an area delimited geographically on the west by the Sierra Madre Oriental. The area is located within the unconventional land region designated by Mexico's Ministry of Energy (SENER). Pyrolysis analyses on 167 samples were performed using the HAWK? instrument. The results of these source rock assessments indicate that most of the samples are classified in the oil to gas condensate window, with low Total Organic Content (TOC) -dominated by non-generative organic carbon- and low Hydrogen Index (HI). A few wells showing higher S1/TOC ratio are recommended for further investigation. There is a general trend of increasing thermal maturity from southern to central-western Tampico Misantla Basin. The geochemical results were integrated with previously published data, thus enhancing our interpretations and providing additional insight on the thermal maturity and the phase of hydrocarbons of the Jurassic–Cretaceous source rock intervals in the region.Vega, F.E., Ziska, L.H., Simpkins, A., Infante, F., Davis, A.P., Rivera, J.A., Barnaby, J.Y., Wolf, J., 2020. Early growth phase and caffeine content response to recent and projected increases in atmospheric carbon dioxide in coffee (Coffea arabica and C. canephora). Scientific Reports 10, 5875. [CO2] effects on growth and secondary chemistry are well characterized for annual plant species, little is known about perennials. Among perennials, production of Coffea arabica and C. canephora (robusta) have enormous economic importance worldwide. Three Arabica cultivars (Bourbon, Catimor, Typica) and robusta coffee were grown from germination to ca. 12 months at four CO2 concentrations: 300, 400, 500 or 600 ppm. There were significant increases in all leaf area and biomass markers in response to [CO2] with significant [CO2] by taxa differences beginning at 122–124 days after sowing (DAS). At 366–368 DAS, CO2 by cultivar variation in growth and biomass response among Arabica cultivars was not significant; however, significant trends in leaf area, branch number and total above-ground biomass were observed between Arabica and robusta. For caffeine concentration, there were significant differences in [CO2] response between Arabica and robusta. A reduction in caffeine in coffee leaves and seeds might result in decreased ability against deterrence, and consequently, an increase in pest pressure. We suggest that the interspecific differences observed (robusta vs. Arabica) may be due to differences in ploidy level (2n?=?22 vs. 2n?=?4x = 44). Differential quantitative and qualitative responses during early growth and development of Arabica and robusta may have already occurred with recent [CO2] increases, and such differences may be exacerbated, with production and quality consequences, as [CO2] continues to increase.Verbeeck, N., Caprioli, R.M., Van de Plas, R., 2020. Unsupervised machine learning for exploratory data analysis in imaging mass spectrometry. Mass Spectrometry Reviews 39, 245-291. mass spectrometry (IMS) is a rapidly advancing molecular imaging modality that can map the spatial distribution of molecules with high chemical specificity. IMS does not require prior tagging of molecular targets and is able to measure a large number of ions concurrently in a single experiment. While this makes it particularly suited for exploratory analysis, the large amount and high‐dimensional nature of data generated by IMS techniques make automated computational analysis indispensable. Research into computational methods for IMS data has touched upon different aspects, including spectral preprocessing, data formats, dimensionality reduction, spatial registration, sample classification, differential analysis between IMS experiments, and data‐driven fusion methods to extract patterns corroborated by both IMS and other imaging modalities. In this work, we review unsupervised machine learning methods for exploratory analysis of IMS data, with particular focus on (a) factorization, (b) clustering, and (c) manifold learning. To provide a view across the various IMS modalities, we have attempted to include examples from a range of approaches including matrix assisted laser desorption/ionization, desorption electrospray ionization, and secondary ion mass spectrometry‐based IMS. This review aims to be an entry point for both (i) analytical chemists and mass spectrometry experts who want to explore computational techniques; and (ii) computer scientists and data mining specialists who want to enter the IMS field. Vranjes-Wessely, S., Misch, D., Issa, I., Kiener, D., Fink, R., Seemann, T., Liu, B., Rantitsch, G., Sachsenhofer, R.F., 2020. Nanoscale pore structure of Carboniferous coals from the Ukrainian Donets Basin: A combined HRTEM and gas sorption study. International Journal of Coal Geology 224, 103484. compositional, depositional and maturity related influencing factors affect the complex pore structure of coal. To study the pore structural evolution at nanoscale, a well characterized sample set of vitrinite-rich Carboniferous coals from the Ukrainian Donets Basin, covering a maturity interval from 0.69 to 1.47%Rr, was selected. Conventional bright field transmission electron microscopy (BF TEM) and high-resolution TEM (HRTEM) imaging was used to directly determine pore size distributions, pore morphology, geometry factors and other structural features, while gas invasion techniques such as low-pressure gas adsorption (CO2 and N2) were used for the investigation of micro- and mesopore structural parameters. High-pressure CH4 sorption experiments revealed changes in the methane storage capacity within the investigated maturity range, while associated structural changes of vitrinite were monitored by Raman spectroscopy. The results indicate pore occlusion in vitrinite mainly at peak oil window maturity, the sensibility of micro- and mesopore structure to thermal maturity and the importance of organic sulphur as a catalyst for kinetics of structural modification. Observed structural changes at 1.10%Rr were related to the onset of wet-gas generation.A structural control on micromechanical properties of vitrinite is indicated by the correlation between reduced elastic moduli from a previous study and average nanopore diameters obtained by HRTEM. The applied comprehensive approach improved the understanding of depositional and maturity-related processes that may affect pore evolution and resulting gas storage capacity of coals.Vuillemin, A., Friese, A., Wirth, R., Schuessler, J.A., Schleicher, A.M., Kemnitz, H., Lücke, A., Bauer, K.W., Nomosatryo, S., von Blanckenburg, F., Simister, R., Ordo?ez, L.G., Ariztegui, D., Henny, C., Russell, J.M., Bijaksana, S., Vogel, H., Crowe, S.A., Kallmeyer, J., the Towuti Drilling Project Science team, 2020. Vivianite formation in ferruginous sediments from Lake Towuti, Indonesia. Biogeosciences 17, 1955-1973. lacustrine systems, such as Lake Towuti, Indonesia, are characterized by a specific type of phosphorus cycling in which hydrous ferric iron (oxyhydr)oxides trap and precipitate phosphorus to the sediment, which reduces its bioavailability in the water column and thereby restricts primary production. The oceans were also ferruginous during the Archean, thus understanding the dynamics of phosphorus in modern-day ferruginous analogues may shed light on the marine biogeochemical cycling that dominated much of Earth's history. Here we report the presence of large crystals (>5?mm) and nodules (>5?cm) of vivianite – a ferrous iron phosphate – in sediment cores from Lake Towuti and address the processes of vivianite formation, phosphorus retention by iron and the related mineral transformations during early diagenesis in ferruginous sediments.Core scan imaging, together with analyses of bulk sediment and pore water geochemistry, document a 30?m long interval consisting of sideritic and non-sideritic clayey beds and diatomaceous oozes containing vivianites. High-resolution imaging of vivianite revealed continuous growth of crystals from tabular to rosette habits that eventually form large (up to 7?cm) vivianite nodules in the sediment. Mineral inclusions like millerite and siderite reflect diagenetic mineral formation antecedent to the one of vivianite that is related to microbial reduction of iron and sulfate. Together with the pore water profiles, these data suggest that the precipitation of millerite, siderite and vivianite in soft ferruginous sediments stems from the progressive consumption of dissolved terminal electron acceptors and the typical evolution of pore water geochemistry during diagenesis. Based on solute concentrations and modeled mineral saturation indices, we inferred vivianite formation to initiate around 20?m depth in the sediment. Negative δ56Fe values of vivianite indicated incorporation of kinetically fractionated light Fe2+ into the crystals, likely derived from active reduction and dissolution of ferric oxides and transient ferrous phases during early diagenesis. The size and growth history of the nodules indicate that, after formation, continued growth of vivianite crystals constitutes a sink for P during burial, resulting in long-term P sequestration in ferruginous sediment.Wampler, J., Thiemens, M., Cheng, S., Zhu, Y., Schuller, I.K., 2020. Superconductivity found in meteorites. Proceedings of the National Academy of Sciences 117, 7645-7649.: In this paper, we report the presence of superconducting material in two meteorites. We further characterize these phases as alloys of lead, tin, and indium. These findings could impact our understanding of several astronomical environments. Superconducting particles in cold environments could affect planetary formation, shape and origin of magnetic fields, dynamo effects, motion of charged particles, and other processes.Abstract: Meteorites can contain a wide range of material phases due to the extreme environments found in space and are ideal candidates to search for natural superconductivity. However, meteorites are chemically inhomogeneous, and superconducting phases in them could potentially be minute, rendering detection of these phases difficult. To alleviate this difficulty, we have studied meteorite samples with the ultrasensitive magnetic field modulated microwave spectroscopy (MFMMS) technique [J. G. Ramírez, A. C. Basaran, J. de la Venta, J. Pereiro, I. K. Schuller, Rep. Prog. Phys. 77, 093902 (2014)]. Here, we report the identification of superconducting phases in two meteorites, Mundrabilla, a group IAB iron meteorite [R. Wilson, A. Cooney, Nature 213, 274–275 (1967)] and GRA 95205, a ureilite [J. N. Grossman, Meteorit. Planet. Sci. 33, A221–A239 (1998)]. MFMMS measurements detected superconducting transitions in samples from each, above 5 K. By subdividing and remeasuring individual samples, grains containing the largest superconducting fraction were isolated. The superconducting grains were then characterized with a series of complementary techniques, including vibrating-sample magnetometry (VSM), energy-dispersive X-ray spectroscopy (EDX), and numerical methods. These measurements and analysis identified the likely phases as alloys of lead, indium, and tin.Wang, A., Cao, D., Wei, Y., Nie, J., Qin, R., 2020. Comparison of nanopore evolution in vitrinite and inertinite in coalbed methane reservoirs during coalification. Journal of Natural Gas Science and Engineering 78, 103289. different responses of vitrinite and inertinite to thermal metamorphism strongly affect the evolution of nanopores in different macerals of coal reservoirs. In order to reveal these differences during coalification, vitrinite and inertinite samples were handpicked from 10 block coal samples. A series of laboratory experiments were performed to explore the macromolecular structure and nanopores of the samples. The results indicate that the nanopore structure of the vitrinite showed obvious regularities with the reflectance of vitrinite (in oil, Ro), but that of the inertinite did not. The macromolecular structure of the inertinite did not correlate with Ro, whereas the vitrinite showed obvious correlations with Ro. Therefore, the nanopore structure of the inertinite cannot be affected by changes in Ro. The nanopore structures of both the vitrinite and inertinite were affected by the changes of macromolecular structures. The detachment of the aliphatic side chains and the promotion of the aromatic degree and the aromatic ring polycondensation degree decreased the micropore surface area (micro-SA) because the longer aliphatic side chains and lower degree of aromatic ring polycondensation make the surface of the coal particle more heterogeneous. The increases in the aromatic degree and aromatic ring polycondensation degree increased the mesopore volume (Vmes), total pore volume excluding micropores (VT), mesopore surface area (meso-SA), and Brunauer–Emmett–Teller (BET) specific surface area (BET-SA) because more isolated pores were connected with each other; thus, more interspace emerged among the aromatic ring layers with an increase in Ro. However, this does not mean that these regularities of inertinite are related to the coal rank, because macromolecular structures of the inertinite had been fixed prior to the coal formation and is not sensitive to coalification. These results are expected to enhance the understanding of the differences in vitrinite and inertinite nanopore structure evolution that occurs during coalification.Wang, C., Kong, S., Liu, Y., Gao, Y., 2020. Measurement and modeling of the adsorption/desorption behavior of light hydrocarbons on shale. Energy & Fuels 34, 4579-4586. the adsorption/desorption behavior, as the primary phenomenon in shale reservoirs, is crucial for shale resource production, which is necessary in approximating the gas-in-place estimation. CH4 and C2H6 in shale gas are two common dominating gas components. We first measure the adsorption/desorption isotherms of CH4 and C2H6 at temperatures of 313.15–333.15 K. The maximum operating pressures for CH4 and C2H6 are 50 and 30 bar, respectively. Relationships of the physical properties of core samples with adsorption capacities of CH4 and C2H6 are analyzed. In addition, the accuracy of four popular adsorption models, i.e., Langmuir, Brunauer–Emmett–Teller (BET), Dubinin–Astakhov (D–A), and Dubinin–Radushkevich (D–R), is quantitatively evaluated by matching with the measured data. Test results show that C2H6 shows more obvious adsorption/desorption hysteresis compared to CH4. In addition, the measured adsorption capacity of C2H6 is much stronger than that of CH4. This indicates that C2H6 exhibits more affinity on the organic-rich shale. It is observed that the total organic carbon (TOC) content correlates linearly with the gas adsorption capacities. In comparison to the TOC content, the BET surface area shows less effect on adsorption capacity. In addition, we found that the D–A model shows the most accuracy among the four popular adsorption models in describing CH4 and C2H6 adsorption. However, Langmuir adsorption is not suitable in reproducing the adsorption of heavier hydrocarbons, i.e., C2H6.Wang, C., Liu, Y., Gao, Y., 2020. Comparison of the absolute adsorption of CH4, n-C4H10, and CO2 on shale. Energy & Fuels 34, 4466-4473. knowledge of the absolute adsorption of light hydrocarbons and CO2 is significant for shale reservoir assessment and CO2 stimulation optimization. In this work, excess adsorption isotherms are first obtained for CH4, n-C4H10, and CO2 on typical shale. The simplified local density (SLD) theory is then used to obtain the adsorption-phase density for CH4, n-C4H10, and CO2 in organic pores, which is then employed for absolute adsorption calculation. The absolute adsorption of CH4, n-C4H10, and CO2 is compared to prove the potential of CO2 for shale hydrocarbon recovery as well as CO2 sequestration in shale reservoirs. The results show that CH4, n-C4H10, and CO2 can form adsorption layers and result in a much higher adsorbed phase density than that at the pore center. Based on the SLD theory, C4H10 shows the highest adsorbed density on the shale surface than CO2 and CH4 at all pressure ranges. In addition, absolute adsorption is higher than the excess values in line with the previous molecular simulation methods. Absolute adsorption is calculated in the order of n-C4H10 > CO2 > CH4, indicating the suitability of CO2 for CH4 recovery but also that it may not be feasible for recovering heavier hydrocarbons, i.e., n-C4H10. This study provides insights into the mechanism of shale resources recovery using CO2 method, which is theoretically crucial for shale resource assessment and production optimization.Wang, C., Peng, P., Li, Z.-X., Pisarevsky, S., Denyszyn, S., Liu, Y., Gamal El Dien, H., Su, X., 2020. The 1.24–1.21?Ga Licheng large igneous province in the North China craton: Implications for paleogeographic reconstruction. Journal of Geophysical Research: Solid Earth 125, e2019JB019005. geochronological, geochemical, and paleomagnetic studies of mafic dyke swarms, often associated with mantle plumes, can provide unique constraints on paleogeographic reconstructions. Mafic dykes with baddeleyite U–Pb ages of 1,233 ± 27 Ma (SIMS), 1,206.7 ± 1.7 Ma (TIMS), 1,214.0 ± 4.9 Ma (TIMS), and 1,236.3 ± 5.4 Ma (TIMS) have been identified in the eastern North China Craton. Geochemical data indicate subalkaline to alkaline basalt compositions with OIB‐like trace element signatures and an intraplate tectonic setting. In addition to these geochemical signatures, the radiating geometry of these dykes also suggests a 1.24–1.21 Ga large igneous province caused by a mantle plume event. A new ~1.24 Ga paleomagnetic pole at 2.0°N, 165.1°E, A95 = 11.0°, N = 9 and an ~1.21 Ga VGP at ?23.0°N, 92.5°E, dp/dm = 4.7°/7.8° have been obtained from these dykes, with the 1.24 Ga pole supported by positive baked contact test. Our paleomagnetic analyses suggest that the North China Craton and the proto‐Australian continent could have been separated by 1.24–1.21 Ga from an established Nuna connection at ca. 1.32 Ga. By comparison with Laurentia paleopoles, we present the paleogeography of dispersing North China, proto‐Australian, and Laurentia cratons in the late Mesoproterozoic during the breakup of the supercontinent Nuna.Wang, J., Belhaj, H., Bera, A., 2020. Investigations on geological aspects of capillary transition zones of carbonate reservoirs by applied imaging techniques. International Journal of Oil, Gas and Coal Technology 24, 85-101. study focuses on the petrographic analysis of thin sections of the rock composites such as grain and cement, pore types and geometry, diagenetic events like dissolution and compaction, their modifications on the pore systems, factors that decide wettability and rock-fluid interaction, which has an impact on relative permeability. An imaging technique such as computerised tomography (CT) scan has been used to find out more information on the geometry, texture, and distribution of the pore systems of the transition zone samples which control petrophysical properties of 17 rock samples. Thin section and petrophysical study were conducted to examine the diagenesis of the samples. It has been found that five major diagenetic processes have affected this transition zone including micritisation, dissolution, cementation, dolomitisation, and compaction. Medical CT scan confirmed the presence of three types of heterogeneities varying from low to medium to high in the rock samples of the transition zones.Wang, J., Wang, Z., Wang, Y., Liu, Z., Li, Y., 2020. CO2 replacing CH4 behaviors under sub- and supercritical conditions. Energy & Fuels 34, 4353-4365. CO2 into deep coal seams is key to successful CO2 sequestration and enhancing coalbed methane production; however, various underground conditions influence the process. In this study, experiments were conducted to determine optimum conditions for replacing CH4 with CO2 injection at different temperatures (20, 30, and 40 °C), pressures (2, 3, and 4 MPa), and supercritical conditions (35, 45, and 55 °C). The results show that the proportion of adsorbed CH4 decreased with decreasing desorption pressure but increased with increasing temperature. Low temperatures were relatively more conducive to replacing CO2 with CH4. With an increase in the original CH4 adsorption equilibrium pressure, there was an increase in CH4 adsorbed proportion but a decrease in CO2 adsorbed concentration. Desorption rates showed that the replacement effect was superior under low original reservoir pressures. Under supercritical conditions, the maximum Gibbs adsorption volume for CO2 was obtained, and the absolute adsorption volume conformed to classical Langmuir curves. During the replacement process, the percentage of adsorbed CO2 increased with increasing temperature, while the concentration of CH4 decreased. The CH4 desorption rate was higher, and the displacement effect was superior when temperature and pressure were close to the critical condition within the supercritical range.Wang, K., Damarla, H.R., Berman, I.C., Staack, D., 2020. High dose rate electron beam irradiation of heavy alkanes in a multi-phase flow system. Fuel 274, 117695. high energy electron beam (10?MeV, LINAC) was used to irradiate mineral oils in a continuous flow system to study radiation effect on large alkane hydrocarbons at constant temperatures (80 and 150?°C). Oil flows down an open channel with methane or helium bubbling from the bottom. The gas mixes with the oil but also may be reactive. Oil was irradiated with about 300–500?kGy by passing 20–30 times down the channel at 18–24?kGy per pass. Analysis by GC-FID showed 7–12% conversion in treated samples and about 60–70% product selectivity to light hydrocarbons right after the irradiation experiment. Stability of products was tested after two years and showed reduced conversion to light products. Selectivity to light products was nearly 100% and dropped to 72% after two years in sample treated with methane. Initially 63%, after aging product selectivity to lights became 46% in sample irradiated at higher temperature and reduced from 62% to 18% in sample irradiated at lower temperature. Overall conversion yields in the flow system are 4–7 molecules/100?eV higher than typical literature values for batch processing of alkanes and cycloalkanes. Irradiation with methane had higher yields and higher selectivity to lighter products compared to helium. Product selectivity to light products is 72% after two years and total yield to lights is 4.4 molecules/100?eV. Methane gas led to higher yield with no viscosity change. Product instability may cause significant economics loss in irradiation upgrading of heavy oils and needs to be addressed.Wang, M., Chen, Y., Bain, W.M., Song, G., Liu, K., Zhou, Z., Steele-MacInnis, M., 2020. Direct evidence for fluid overpressure during hydrocarbon generation and expulsion from organic-rich shales. Geology 48, 374-378. overpressures are widely expected during hydrocarbon generation and expulsion from source rocks, yet direct evidence for this phenomenon is lacking in the case of organic-rich shales. Here we show that formation of bed-parallel fibrous calcite veins in mature laminated organic-rich shales in the Eocene Dongying depression, Bohai Bay Basin, east China, occurred in direct response to fluid overpressure due to hydrocarbon generation. The evidence for overpressure is recorded by coexisting primary aqueous and petroleum inclusions in the calcite fibers. Our results show that all analyzed fluid-inclusion assemblages record variable degrees of overpressure during vein dilation, ranging from only modestly in excess of hydrostatic, to approaching and perhaps exceeding lithostatic. Thus, our results indicate that fluid pressures during dilation of horizontal veins are not necessarily equal to the opposing force of overburden throughout the history of opening. This suggests that at least some of the vein dilation is accommodated by concomitant narrowing of the adjacent wall-rock laminae, likely by scavenging (dissolution and reprecipitation) of CaCO3 from the adjacent wall rock.Wang, Q., Chen, Y., Tamburini, D., 2020. Was lacquer the key ingredient for luxurious jinyin pingtuo products in the Tang Dynasty of China (AD 618–907)? Archaeometry 62, 646-659. pingtuo is one of the most sumptuous decorative methods applied on ‘lacquered' objects described in Tang dynasty literatures. Two Tang dynasty objects, a silver bowl and a bronze mirror, in the British Museum collection said to be made by this technique, were scientifically examined to confirm the application of the technique. Although the metal décors levelled with the rest of the surfaces on these objects suggested the application of the pingtuo method, lacquer, a major ingredient of this technique, was not identified by Py (HMDS)‐GC–MS in any of the four samples analysed. The results question the use of lacquer in the pingtuo technique as usually described. The detection of shellac and oil in the bronze mirror aligns with other studies on similar objects, whereas proteinaceous materials as main ingredient of the decorative layers of the silver bowl, appear less usual. Further comparative study by scientific analysis of similar objects in other museum collections or from excavations is required to help better understand the use of lacquer in ancient China.Wang, R., Liu, Z., 2020. Stable isotope evidence for recent global warming hiatus. Journal of Earth Science 31, 419-424. mean surface air temperature (SAT) has remained relative stagnant since the late 1990s, a phenomenon known as global warming hiatus. Despite widespread concern and discussion, there is still an open question about whether this hiatus exists, partly due to the biases in observations. The stable isotopic composition of precipitation in mid- and high-latitude continents closely tracks change of the air temperature, providing an alternative to evaluate global warming hiatus. Here we use the long-term precipitation δ18O records available to investigate changes in SAT over the period 1970–2016. The results reveal slight decline in δ18O anomaly from 1998 to 2012, with a slope of ?0.000 4‰ decade?1 which is significantly different from that of pre-1998 interval This downward δ18O anomaly trend suggests a slight cooling for about ?0.001 oC decade?1, corroborating the recent hiatus in global warming. Our work provides new evidence for recent global warming hiatus and highlights the potential of utilizing precipitation isotope for tracking climate changes.Wang, T., Liang, C., Xu, H., An, Y., Xiao, S., Zheng, M., Liu, L., Nie, L., 2020. Incorporation of nonstandard amino acids into proteins: principles and applications. World Journal of Microbiology and Biotechnology 36, 60. cellular ribosome shows a naturally evolved strong preference for the synthesis of proteins with standard amino acids. An in-depth understanding of the translation process enables scientists to go beyond this natural limitation and engineer translating systems capable of synthesizing proteins with artificially designed and synthesized non-standard amino acids (nsAA) featuring more bulky sidechains. The sidechains can be functional groups, with chosen biophysical or chemical activities, that enable the direct application of these proteins. Alternatively, the sidechains can be designed to contain highly reactive groups: enabling the ready formation of conjugates via a covalent bond between the sidechain and other chemicals or biomolecules. This co-translational incorporation of nsAAs into proteins allows for a vast number of possible applications. In this paper, we first systematically summarized the advances in the engineering of the translation system. Subsequently, we reviewed the extensive applications of these nsAA-containing proteins (after chemical modification) by discussing representative reports on how they can be utilized for different purposes. Finally, we discussed the direction of further studies which could be undertaken to improve the current technology utilized in incorporating nsAAs in order to use them to their full potential and improve accessibility across disciplines.Wang, W., Wang, X., Li, Y., Liu, S., Yao, S., Song, G., 2020. Study on the characteristics of natural gas hydrate crystal structures during decomposition process. Fuel 271, 117537. decomposition is inevitable in the process of hydrate formation, and has an important research significance. In order to study the crystal decomposition process, the formation and flow of hydrate particles in natural gas?+?pure water system were experimentally studied in a high-pressure visual autoclave. During the experiments, the high-speed digital camera was used to capture the micro-morphology and decomposition process of gas hydrate particles, and the high definition camera was used to capture the agglomeration state of nature gas hydrate at the visual window to connect macro-and micro-phenomena organically. By analyzing the data obtained from experiments, we find that the micro-morphology of hydrate particles can be roughly divided into two categories: planar flake particles and polyhedral solid particles. The planar flake particles are further refined into non-trunk snowflake particles and dendritic particles with trunk growth. When snowflake particles begin to decompose, they tend to decrease in area and have rounded edges. The decomposition time of dendritic particles is longer, and there is always trunk in the system. During the decomposition process, the number of particles gradually decreases to zero, but there will be a slightly increase. Meanwhile, it is found that the higher heating temperature and initial pressure will aggravate the fluctuation of particle number. Finally, according to the microscopic changes of hydrate particles in the decomposition process obtained by high-speed digital camera and other equipment, and based on the independent physical models of two types of hydrate particles, the physical model of hydrate particles decomposition is established.Wang, W., Yue, D., Eriksson, K.A., Qu, X., Li, W., Lv, M., Zhang, J., Zhang, X., 2020. Quantification and prediction of pore structures in tight oil reservoirs based on multifractal dimensions from integrated pressure- and rate-controlled porosimetry for the Upper Triassic Yanchang Formation, Ordos Basin, China. Energy & Fuels 34, 4366-4383. complex pore structures is important for evaluating tight oil reservoir performance and predicting favorable pore structure. However, quantitative characterization of pore structure in tight sandstones by combining different methods is still poorly understood. Using the Upper Triassic Yanchang Formation in Ordos Basin, China as a case study, we first introduce a new method to quantitatively characterize full-range pore-throat size distribution (PSD) through multifractal dimension analysis of integrated pressure-controlled porosimetry (PCP) and rate-controlled porosimetry (RCP). Second, we propose a technique using helium porosity and nitrogen permeability to obtain multifractal dimensions in an attempt to predict favorable pore structure in tight oil reservoirs. In the new method of obtaining full-range PSD, PCP and RCP data were merged at various positions instead of the same position for each sample. Multifractal dimension curves derived from full-range pores are divided into four segments as D1, D2, D3, and D4, corresponding to the fractal characteristics of large pores, large pore throats, small pores, and small pore throats, respectively. Among them, the fractal dimension D2 of large pore throats and D4 of small pore throats from the combination of PCP and RCP significantly control petrophysical properties (porosity and permeability). The multifractal dimensions obtained using porosity and permeability data input through a back-propagation (BP) neural network method show that the relatively large D2 and the relatively small D4 correspond to favorable pore structure and good reservoir quality. The results of this research significantly improve our understanding of complex pore characteristics and prediction of favorable pore structure in tight reservoirs, thus enhancing hydrocarbon exploration and production.Wang, Y., Cao, J., Tao, K., Li, E., Ma, C., Shi, C., 2020. Reevaluating the source and accumulation of tight oil in the middle Permian Lucaogou Formation of the Junggar Basin, China. Marine and Petroleum Geology 117, 104384. middle Permian Lucaogou Formation in the Jimusar Sag, Junggar Basin, NW China, is a world-class example of tight oil accumulations in lacustrine sedimentary sequences. Previous studies have indicated that the main oil accumulation mechanism in this system is near-source accumulation within upper and lower “sweet spots” (i.e., reservoirs). Here we reveal the complexity of oil source and accumulation in this tight oil system is greater than previously thought. A set of mudstones are developed between the upper and lower sweet spots of the Lucaogou Formation and are thus termed the middle section mudstones. They have previously been little studied as few intervened reservoir rocks are developed within the sequences. Here we report their oil generation and contribution for the first time. The mudstones are 97–182?m thick and have total organic carbon contents of 0.67–12.31?wt%. The kerogen is mainly type II, with small amounts of types I and III, and is in the mature stage. These data suggest that the middle section mudstones have good hydrocarbon generation potential. Oil–source correlations reveal a complex history of tight oil migration and accumulation. The oils generated in the upper part of the middle section mudstones migrated northward to the basin margins and southeastward to the basin center. In contrast, oil generated in the lower part of the middle section mudstones migrated westward to the west–central and central regions. The oil migration resulted in complex tight oil accumulation, which reflects the reservoir heterogeneity. Our data suggest that such reservoir heterogeneity appears to be typical of tight oil accumulations in continental lacustrine basins. In the study area, future evaluation, exploration, and exploitation of tight oil should also focus on the middle section mudstones and associated sweet spots in addition to the commonly-acknowledged upper and lower sweet spots.Wang, Y., Li, L., Sun, Y., He, L., Sheng, X., 2020. Impact of the fliF gene on biotite weathering of Rhizobium pusense S41. Geomicrobiology Journal 37, 308-314. have been reported to weather silicate mineral, however, molecular mechanisms underlying mineral weathering of Rhizobium strain is unclear. In this study, biotite weathering behaviors were compared among the mineral-weathering Rhizobium pusense S41, its mutants created by deleting the fliF gene involved in flagellar protein synthesis, and its complemented strain. Flagellum was observed in strain S41 but not in its mutant S41ΔfliF. Mobilized Fe and Al concentrations decreased in the presence of S41ΔfliF during mineral weathering process compared to strain S41. No significant differences in the gluconic acid concentration and pH values were found between strains S41 and S41ΔfliF during the mineral weathering process except for day 2. A similar bacterial growth in the culture medium was observed between strains S41 and S41ΔfliF, however, significantly lower cell numbers on the mineral surface were observed for S41ΔfliF compared to strain S41. Furthermore, biofilm production was depressed for S41ΔfliF compared to strain S41. The results showed the important role of a flagellum of strain S41 in biotite weathering and that the fliF gene of strain S41 exhibited important impacts on mineral weathering activity and biofilm production.Wang, Y., Xue, J., Wang, D., Xue, Q., 2020. Lattice Boltzmann method for simulation of shale gas flow in kerogen nano-pores considering temperature dependent adsorption. International Journal of Oil, Gas and Coal Technology 23, 409-426. Due to the combined action of gas adsorption, surface diffusion and slippage, classical simulation approaches based on Darcy's law may not be appropriate for simulating shale gas flow in shale. In this work, a novel lattice Boltzmann (LB) model is proposed to study shale gas flow in a kerogen pore by introducing temperature dependent thickness of adsorption layer. The surface diffusion, which is caused by gradient of adsorption density, is considered as the slippage velocity on the surface of adsorption layer. The proposed LB model was adopted to simulate shale gas flow in a nano-pore. The results show that adsorption can significantly decrease the permeability of nano-pores. Surface diffusion improves the gas movement in nano-pores at lower pressure. With the decrease of pore size, the adsorbed layer had more impacts on gas permeability. Increasing temperature improves gas flow ability in nano-pores when pore size is less than 10nm.Wang, Y.S., Liu, L., Fu, Q., Sun, J., An, Z.Y., Ding, R., Li, Y., Zhao, X.D., 2020. Effect of Bacillus subtilis on corrosion behavior of 10MnNiCrCu steel in marine environment. Scientific Reports 10, 5744. widely exists in wet natural environment such as soil, water and air, and is often studied as one of representative microorganisms for microbiologically influenced corrosion(MIC) research. In this paper, the growth curve of Bacillus subtilis isolated from marine environment was determined by turbidimetry and its effect on corrosion behavior of 10MnNiCrCu steel was studied by open circuit potential, AC impedance, polarization curve and scanning electron microscopy(SEM). The results showed that with the change of the growth curve of Bacillus subtilis(BS), the open circuit potential(Eocp) shifted positively and then negatively, and the charge transfer resistance shown by AC impedance was much lower than that of the sterile system, increasing first and then decreasing. The polarization curves showed that the corrosion current density in BS medium was obviously higher than that in sterile system. The corrosion morphology observation showed that although a biofilm by BS developed on the steel surface, the localized corrosion of 10MnNiCrCu steel was aggravated due to the acidness of the metabolite itself and the biofilm with access for electrolyte ions.Wang, Z., Tan, J., Boyle, R., Hilton, J., Ma, Z., Wang, W., Lyu, Q., Kang, X., Luo, W., 2020q. Evaluating episodic hydrothermal activity in South China during the early Cambrian: Implications for biotic evolution. Marine and Petroleum Geology 117, 104355. early Cambrian (541–514?Ma) was a crucial interval for the evolution of life on Earth, popularly known as the “Cambrian Explosion”. Here, we report the timing of changes in hydrothermal and depositional inputs, as well as paleo-redox state, which may have influenced biogeochemical changes. According to high-resolution petrology, fossil distributions, isotopic records, and inorganic geochemistry, the lower Cambrian of the South China can be subdivided into four intervals: the lowermost Cambrian Zhujiaqing Formation (Cam-I); the Cambrian Stage 2 Shiyantou Formation (Cam-II); the lower part of the Cambrian Stage 3 Yu'anshan Formation (Cam-III); and the mid–upper Cambrian Stage 3 and the middle–upper part of the Yu'anshan Formation, continuing into the Canglangpu Formation (Cam-IV). Hydrothermal events are detected during the early Cam-I, Cam-II, and Cam-III intervals. During the early Cam-I and Cam-II intervals, these events coincided with extensive bottom water euxinia, which in turn may have restricted the spread or proliferation of Ediacaran fauna and small shelly fauna. Through the whole Cam-III interval, further hydrothermal events occurred concurrently with euxinic and ferruginous conditions, probably within a single spatially stratified water column, again plausibly restricting the spread of aerobic organisms. In conjunction with the cessation of hydrothermal events and the gradual lowering of sea level during the late Cam-III, oxic water environments gradually spread into relatively deep-water regions, concurrent with the emergence of the Chengjiang and Qingjiang faunas. These data suggest that periodic hydrothermal events may have had a significant impact on the spread, radiation and extinction of macroscopic fauna during the early Cambrian in South China.Wang, Z., Wang, X., Shi, X., Tang, D., Stüeken, E.E., Song, H., 2020. Coupled nitrate and phosphate availability facilitated the expansion of eukaryotic life at circa 1.56?Ga. Journal of Geophysical Research: Biogeosciences 125, e2019JG005487. geochemical and paleontological studies have revealed a significant ocean oxygenation episode and an evolutionary leap of eukaryotes at the onset of the Mesoproterozoic. However, the potential role of nitrogen availability and its interaction with other nutrients in these environmental and biological events have not been investigated. Here we present an integrated study of nitrogen isotopes (δ15N), organic carbon isotopes (δ13Corg), and major and trace element concentrations from Member III of the Gaoyuzhuang Formation in the central North China Craton where the earliest macroscopic multicellular eukaryotic fossils were reported. The enrichments of redox‐sensitive elements (Mo, U, and V), coupled with Mo‐U covariations, δ13Corg, and I/(Ca + Mg), indicate that the Gaoyuzhuang Member III in the study area was deposited in largely suboxic‐anoxic environments with ephemeral occurrences of euxinia. These data reinforce previous inferences of a strongly redox stratified ocean during the early Mesoproterozoic, but a pulsed oxygenation event may have resulted in deepening of the chemocline. The high δ15N values from the study section are interpreted as a result of aerobic N cycling and the presence of a fairly stable nitrate pool in the surface oxic layer, possibly due to the combined effects of oxygenation and low primary productivity. Increased availability of nitrate could have contributed to the expansion of eukaryotic life at this time. However, our data also suggest that nitrate alone was not the only trigger. Instead, this evolutionary leap was likely facilitated by multiple environmental factors, including a rise in O2 levels and increasing supplies of phosphorus and other bio‐essential trace elements.Wary, M., Kornilova, O., Russell, M., Rosell-Melé, A., 2020. Biomarker fingerprint of debris flow deposits as a paleoproxy for IRD sources in the last glacial North Atlantic. Paleoceanography and Paleoclimatology 35, e2020PA003850. Investigating the spatiotemporal dynamics of iceberg discharges during the last glacial period constitutes a major challenge for paleoclimate research. In recent decades, many ice-rafted debris (IRD) provenance studies, mostly based on the comparison of the inorganic signature of IRD-rich layers and surrounding continental bedrock, have differentiated main subareas of individual ice sheets as iceberg sources and gauged their dynamic interplay. Diagnosis of specific source ice streams has nonetheless remained limited. Here we propose a new IRD provenance methodology to refine the identification of iceberg sources. It relies on the organic geochemical characterization of glacigenic debris flow (GDF) deposits to obtain the biomarker fingerprint of IRD sources. To test its potential, we analyze the composition of n-alkanes and chlorophyll-derived pigments in sediments deposited within six major North Atlantic GDF depocenters fed by ice streams draining the surrounding ice sheets. The biomarker fingerprint of GDF deposits appears to (1) be consistent with a common origin of IRD and GDF deposits through erosion of outcrops and transport by ice streams, (2) differ significantly from that of ambient hemipelagic sediments, (3) be specific and unique to each GDF depocenter, making it possible to distinguish the corresponding specific ice streams, (4) be imprinted in IRD-bearing marine sediments, and (5) have remained homogeneous enough through the last glacial to be used as a proxy for IRD sources. The biomarker fingerprint of GDF deposits thus shows strong potential to track the specific source ice streams that delivered IRD to the last glacial North Atlantic.Welker, F., Ramos-Madrigal, J., Gutenbrunner, P., Mackie, M., Tiwary, S., Rakownikow Jersie-Christensen, R., Chiva, C., Dickinson, M.R., Kuhlwilm, M., de Manuel, M., Gelabert, P., Martinón-Torres, M., Margvelashvili, A., Arsuaga, J.L., Carbonell, E., Marques-Bonet, T., Penkman, K., Sabidó, E., Cox, J., Olsen, J.V., Lordkipanidze, D., Racimo, F., Lalueza-Fox, C., Bermúdez de Castro, J.M., Willerslev, E., Cappellini, E., 2020. The dental proteome of Homo antecessor. Nature 580, 235–238. phylogenetic relationships between hominins of the Early Pleistocene epoch in Eurasia, such as Homo antecessor, and hominins that appear later in the fossil record during the Middle Pleistocene epoch, such as Homo sapiens, are highly debated. For the oldest remains, the molecular study of these relationships is hindered by the degradation of ancient DNA. However, recent research has demonstrated that the analysis of ancient proteins can address this challenge. Here we present the dental enamel proteomes of H. antecessor from Atapuerca (Spain) and Homo erectus from Dmanisi (Georgia), two key fossil assemblages that have a central role in models of Pleistocene hominin morphology, dispersal and divergence. We provide evidence that H. antecessor is a close sister lineage to subsequent Middle and Late Pleistocene hominins, including modern humans, Neanderthals and Denisovans. This placement implies that the modern-like face of H. antecessor—that is, similar to that of modern humans—may have a considerably deep ancestry in the genus Homo, and that the cranial morphology of Neanderthals represents a derived form. By recovering AMELY-specific peptide sequences, we also conclude that the H. antecessor molar fragment from Atapuerca that we analysed belonged to a male individual. Finally, these H. antecessor and H. erectus fossils preserve evidence of enamel proteome phosphorylation and proteolytic digestion that occurred in vivo during tooth formation. Our results provide important insights into the evolutionary relationships between H. antecessor and other hominin groups, and pave the way for future studies using enamel proteomes to investigate hominin biology across the existence of the genus Homo.Whitby, H., Planquette, H., Cassar, N., Bucciarelli, E., Osburn, C.L., Janssen, D.J., Cullen, J.T., González, A.G., V?lker, C., Sarthou, G., 2020. A call for refining the role of humic-like substances in the oceanic iron cycle. Scientific Reports 10, 6144. production by phytoplankton represents a major pathway whereby atmospheric CO2 is sequestered in the ocean, but this requires iron, which is in scarce supply. As over 99% of iron is complexed to organic ligands, which increase iron solubility and microbial availability, understanding the processes governing ligand dynamics is of fundamental importance. Ligands within humic-like substances have long been considered important for iron complexation, but their role has never been explained in an oceanographically consistent manner. Here we show iron co-varying with electroactive humic substances at multiple open ocean sites, with the ratio of iron to humics increasing with depth. Our results agree with humic ligands composing a large fraction of the iron-binding ligand pool throughout the water column. We demonstrate how maximum dissolved iron concentrations could be limited by the concentration and binding capacity of humic ligands, and provide a summary of the key processes that could influence these parameters. If this relationship is globally representative, humics could impose a concentration threshold that buffers the deep ocean iron inventory. This study highlights the dearth of humic data, and the immediate need to measure electroactive humics, dissolved iron and iron-binding ligands simultaneously from surface to depth, across different ocean basins.Wiest, L.A., Lukens, W.E., Driese, S.G., Peppe, D.J., Forman, S.L., 2020. Landscape evolution across the Cretaceous/Paleogene boundary in southwestern North Dakota, U.S.A. Cretaceous Research 112, 104470. Hell Creek Formation and overlying Fort Union Formation record a geologically rapid base-level rise that was approximately contemporaneous with the K/Pg extinction and deposition of Chicxulub-impact indicators. An outstanding question that remains is whether this base-level rise is attributable to: 1) a multi-thousand-year transgression adjacent to a relatively low-relief coastal plain, causing a rise in the water table; or 2) catastrophic flooding due to upland denudation, rapid channel accretion, and hydrologic reorganization resulting from wildfires/deforestation consequential of the impact. Herein we aim to address which of these hypotheses is most consistent with a paleolandscape reconstruction at Mud Buttes, a locality where the boundary clay (BC) is coincident with the Hell Creek-Fort Union contact. One hundred twenty-seven trenches were examined laterally across ～2?km transect of K/Pg boundary. The uppermost Hell Creek is comprised of three pedotypes: Pale-Silt Inceptisol (PSI), Olive-Clay Vertisol (OCV), and Chocolate-Clay Vertisol (CCV), which range from moderately well-drained, to variable to poorly drained, to very poorly drained, respectively. All of the BC occurs superjacent to the CCV, despite this pedotype accounting for only ～50% of the pre-event landscape. The edaphic features preserved in the CCV pedotype are not attributable to Paleogene overprinting, which indicates that hydromorphic conditions began prior to the impact. Furthermore, 46% of BC is overlain by lignite, despite lignite occurrence on 17% of the earliest Paleogene landscape. This reveals that the poorest-drained landscape positions of the latest Cretaceous persisted across the boundary. These relationships are most consistent with a non-catastrophic base-level rise.Wignall, P.B., Chu, D., Hilton, J.M., Corso, J.D., Wu, Y., Wang, Y., Atkinson, J., Tong, J., 2020. Death in the shallows: The record of Permo-Triassic mass extinction in paralic settings, southwest China. Global and Planetary Change 189, 103176. Permo-Triassic marine mass extinction has been blamed on a range of culprits including anoxia, acidification, high temperature and increased sedimentation and nutrient influx, the last two being a direct consequence of terrestrial biomass die-off and climatic changes. In marine settings, the role of these kill mechanisms is likely to be depth-dependent with siltation and high temperatures potentially the most consequential in shallowest waters. These ideas have been investigated in a study of the Permo-Triassic boundary beds in western Guizhou and eastern Yunnan (WGEY) which record the transition from littoral coal swamps to an inner shelf/platform fringed by a coastal mudbelt. Anoxic conditions were not developed in such shallow waters but weak dysoxia is seen in the extinction interval, recorded by the presence of pyrite framboids and glauconite, and may have been a factor in the crisis even in coastal waters. High temperatures may also be an extinction factor as evidenced by the brief bloom of microgastropods in the immediate aftermath. The Late Permian peat-forming swamps were subject to considerable in situ erosion that reworked authigenic minerals (chamosite and kaolinite). This material, together with considerable amounts of charcoal, was concentrated in distinctive green sandstone beds. However, the notion that the marine extinction was caused by increased sediment supply, a death-by-siltation mechanism following the collapse of terrestrial biomass, is not supported by the field evidence because a surge in clastic influx onto the shelf is not observed during the extinction interval when a range of carbonates, including microbialites, developed. The sediment was likely trapped in alluvial plains during base-level rise and/or a short period of more arid conditions occurred, reducing the clastic supply in the coastal–shallow marine environments. Ocean acidification is another potent kill mechanism but the occurrence of the extinction within a transgressive, carbonate-dominated interval in the shallow-water locations of WGEY does not support this cause.Williams, J., Zheng, Q., Sederman, A.J., Mantle, M.D., Baart, T., Guédon, C., Gladden, L.F., 2020. In situ determination of carbon number distributions of mixtures of linear hydrocarbons confined within porous media using pulsed field gradient NMR. Analytical Chemistry 92, 5125-5133. field gradient (PFG) NMR measurements, combined with a novel optimization method, are used to determine the composition of hydrocarbon mixtures of linear alkanes (C7–C16) in both the bulk liquid state and when imbibed within a porous medium of mean pore diameter 28.6 nm. The method predicts the average carbon number of a given mixture to an accuracy of ±1 carbon number and the mole fraction of a mixture component to within an average root-mean-square error of ±0.036 with just three calibration mixtures. Given that the method can be applied at any conditions of temperature and pressure at which the PFG NMR measurements are made, the method has the potential for application in characterizing hydrocarbon liquid mixtures inside porous media and at the operating conditions relevant to, for example, hydrocarbon recovery and heterogeneous catalysis.Wolk, S.K., Mayfield, W.S., Gelinas, A.D., Astling, D., Guillot, J., Brody, E.N., Janjic, N., Gold, L., 2020. Modified nucleotides may have enhanced early RNA catalysis. Proceedings of the National Academy of Sciences 117, 8236-8242. modern version of the RNA World Hypothesis begins with activated ribonucleotides condensing (nonenzymatically) to make RNA molecules, some of which possess (perhaps slight) catalytic activity. We propose that noncanonical ribonucleotides, which would have been inevitable under prebiotic conditions, might decrease the RNA length required to have useful catalytic function by allowing short RNAs to possess a more versatile collection of folded motifs. We argue that modified versions of the standard bases, some with features that resemble cofactors, could have facilitated that first moment in which early RNA molecules with catalytic capability began their evolutionary path toward self-replication.Wolrab, D., Chocholou?ková, M., Jirásko, R., Peterka, O., Hol?apek, M., 2020. Validation of lipidomic analysis of human plasma and serum by supercritical fluid chromatography–mass spectrometry and hydrophilic interaction liquid chromatography–mass spectrometry. Analytical and Bioanalytical Chemistry 412, 2375-2388. supercritical fluid chromatography–mass spectrometry (UHPSFC/MS) has a great potential for the high-throughput lipidomic quantitation of biological samples; therefore, the full optimization and method validation of UHPSFC/MS is compared here with ultrahigh-performance liquid chromatography–mass spectrometry (UHPLC/MS) in hydrophilic interaction liquid chromatography (HILIC) mode as the second powerful technique for the lipid class separation. First, the performance of six common extraction protocols is investigated, where the Folch procedure yields the best results with regard to recovery rate, matrix effect, and precision. Then, the full optimization and analytical validation for eight lipid classes using UHPSFC/MS and HILIC-UHPLC/MS methods are performed for the same sample set and applied for the lipidomic characterization of pooled samples of human plasma, human serum, and NIST SRM 1950 human plasma. The choice of appropriate internal standards (IS) for individual lipid classes has a key importance for reliable quantitative workflows illustrated by the selectivity while validation and the calculation of the quantitation error using multiple internal standards per lipid class. Validation results confirm the applicability of both methods, but UHPSFC/MS provides some distinct advantages, such as the successful separation of both non-polar and polar lipid classes unlike to HILIC-UHPLC/MS, shorter total run times (8 vs. 10.5?min), and slightly higher robustness. Various types of correlations between methods (UHPSFC/MS and HILIC-UHPLC/MS), biological material (plasma and serum), IS (laboratory and commercially mixtures), and literature data on the standard reference material show the intra- and inter-laboratory comparison in the quantitation of lipid species from eight lipid classes, the concentration differences in serum and plasma as well as the applicability of non-commercially available internal standard mixtures for lipid quantitation.Wu, X., Ning, Z., Qi, R., Wang, Q., Huang, L., 2020. Pore characterization and inner adsorption mechanism investigation for methane in organic and inorganic matters of shale. Energy & Fuels 34, 4106-4115. pore characterization and the adsorption property for gas shale have been studied widely due to the vigorous exploration of shale gas reservoirs. However, for a particular shale sample, few research studies have focused on the pore characterizations and inner adsorption mechanisms for different types of pores in organic and inorganic matters. In this research, a low-pressure N2/CO2 adsorption method with a novel analysis and a simplified local density (SLD) method with a particular regression were utilized to investigate the pore characteristics and inner adsorption mechanisms for methane in organic micropores and inorganic micropores and nonmicropores. Effective pore characterizations were acquired for these three types of pores. Furthermore, based on the obtained adsorption proportion of each type of pore to the total adsorption of all the pores, the adsorptions in inorganic micropores and nonmicropores were both essential and nonnegligible. Organic micropores are more competitive than inorganic micropores for adsorption owing to their stronger fluid–wall interaction. Due to the variation in density distribution in the pores, excess adsorption possesses positive and negative relationships with micropore size at high and low pressures, respectively, and slightly negative relationship with nonmicropore size. Besides, strong solid–solid molecule interactions and small pores could bring about a high sensitivity of adsorption to the specific surface area (SSA).Wu, Z., He, S., Han, Y., Zhai, G., He, X., Zhou, Z., 2020. Effect of organic matter type and maturity on organic matter pore formation of transitional facies shales: A case study on Upper Permian Longtan and Dalong shales in Middle Yangtze Region, China. Journal of Earth Science 31, 368-384. matter (OM) nanopores developed in transitional facies shales, i.e., the Upper Permian Longtan and Dalong Formations in the Yangtze Platform, China, were investigated to determine the corre- sponding influence of thermal maturity and OM types within the geological conditions. A suite of 16 core samples were taken from Type-III Longtan shales and Type-II Dalong shales from two wells covering a ma- turity (Ro, vitrinite reflectance) ranging from 1.22% to 1.43% and 2.62% to 2.97%, respectively. Integrated analysis of the shale samples was carried out, including field-emission scanning electron microscopy (FESEM), low-pressure N2 and CO2 adsorption, high-pressure CH4 adsorption, and mercury intrusion capillary pressure (MICP) analysis. The fluid inclusions of liquid and gas hydrocarbons trapped in calcite vein samples in Dalong shales of two wells were studied using laser Raman and fluorescence spectroscopy. FE-SEM images indicated that OM pores in different formations varied substantially in terms of shape, size, and distribution density. OM pores in Type-II Dalong shales of Well XY1 were mainly micropore, sparsely distributed in the gas-prone kerogen with a spot-like and irregular shape, while bitumen rarely developed observable pores. In contrast, the morphology of OM pores in Type-III Longtan shales were significantly different, which was due to differences in the OM type. The primary OM pores in some terrestrial woody debris in Longtan shales had a relatively larger pore diameter, ranging from hundreds of nanometers to a few micrometers and were al- most all rounded in shape, which might be one of the factors contributing to larger pore volume and gas adsorption capacity than Dalong shales of Well XY1. Comparing Dalong shales of Well XY1 with relatively lower thermal maturity, there were abundant spongy-like pores, densely developed in the pyrobitumen in Type-II Dalong shales of Well EY1, with an irregular shape and diameter ranging from several to hundreds of nanometers. Many blue fluorescent oil inclusions and a small number of CH4 inclusions mixed with C2H6 could be observed within calcite veins in Dalong shales of Well XY1, whereas only CH4 inclusions could be identified within calcite veins in Dalong shales of Well EJ1. Therefore, thermal maturity not only controlled the type of hydrocarbons generated, but also makes a significant contribution to the formation of OM pores, resulting in larger pore volumes and adsorption capacity of Type-II shale samples in the dry gas window.Xi, Z., Tang, S., Zhang, S., Ye, Y., 2020. Factors controlling organic matter accumulation in the Wufeng–Longmaxi formations in northwestern Hunan Province: Insights from major/trace elements and shale composition. Energy & Fuels 34, 4139-4152. matter (OM) is the material basis of shale gas accumulation, so understanding the mechanisms of OM accumulation plays a critical role in shale gas exploration. The marine shale from the Ordovician Wufeng–Silurian Longmaxi formations is thought to be a good shale gas source in China’s northwestern Hunan Province in the Upper Yangtze platform. A total of 37 samples were collected from a well SY5, and OM accumulation mechanisms were analyzed based on geochemical proxies associated with shale composition. Total organic carbon (TOC) decreased upward from Wufeng to the lower and upper members of the Longmaxi. Average TOC contents were 2.64, 1.24, and 0.29%, respectively. Wufeng shale developed from migrated OM and biogenic quartz, whereas depositional OM and terrigenous quartz were widespread in the lower Longmaxi, and barely any OM was observed in the upper Longmaxi. The Fe–S–C systems and Mo–U covariation suggested that the oxygen level increased from Wufeng to the upper Longmaxi. The organic-rich Wufeng was deposited under anoxic conditions, and redox conditions during the lower Longmaxi deposition fluctuated greatly (suboxic to euxinic) and were mainly suboxic. The upper Longmaxi was deposited under oxic conditions. High excess silica concentrations and the C/P ratio of Wufeng shale implied high paleoproductivity, which may have contributed to phosphorus recycling under a strong reducing environment. P/Ti ratios showed that the lower Longmaxi was deposited under moderate paleoproductivity and the upper Longmaxi was deposited under low paleoproductivity. The Al and Ti concentrations increased and Zr/Al decreased from Wufeng to the upper Longmaxi, reflecting increased terrigenous flux. The high terrigenous flux occurred as the diluent decreased OM concentrations during the Longmaxi deposition. The strong reducing conditions, high paleoproductivity, and low terrigenous flux, which were favorable to OM production and preservation during Wufeng deposition, further determined the content and types of OM and quartz. The high OM and quartz contents were associated with favorable types (migrated OM and biogenic quartz), creating Wufeng shale high-quality reservoirs, which were conducive to shale gas accumulation. Ba and P did not act as paleoproductivity proxies under strong reducing conditions due to their redistribution, and the V-related ratios were unreliable due to high thermal maturity of marine shale. The element Si was not a proxy of terrigenous flux when the silica was biogenic in origin, but the excess silica concentration was a reliable proxy for paleoproductivity.Xia, M., Bao, P., Peng, T., Liu, A., Shen, L., Yu, R., Liu, Y., Li, J., Wu, X., Huang, C., Chen, M., Qiu, G., Zeng, W., 2020. Exploration of potential jarosite biomineralization mechanism based on extracellular polymer substances of Purpureocillium lilacinum Y3. International Biodeterioration & Biodegradation 150, 104941. the present study, the mechanism of jarosite biosynthesis mediated by extracellular polymer substances (EPSs) of Purpureocillium lilacinum strain Y3 at gene level was investigated. Yellow-ocher jarosite minerals covered mycelia pellets entirely within 72h, corresponding to a reduction of Fe3+ of 70.9% in the biomineralization process induced by P. lilacinum Y3. The maximum biomass accumulation reached to 12.9 g/L in pure culture, 2.8 g/L with only 0.02M Fe3+ addition, and 6.4 g/L with both 0.02M Fe3+ and 0.1M K+ addition, respectively, indicating that jarosite biosynthesis largely alleviated the inhibition of Fe3+ to the fungal strain. Thereafter, the analysis of EPSs compositions suggested that protein content was affected more evidently than polysaccharides in the biomineralization system. Furthermore, real time quantitative PCR assays revealed that signal transduction genes and abundance of membrane transporters were activated quickly in responding to the stimulation of Fe3+ and fungus-mineral interactions. Then, the expression of adhesive proteins and extracellular proteins was highly up-regulated to facilitate the formation of jarosite minerals on the cell surface. Finally, X-ray photoelectron spectroscopy analysis supported that amine, carboxyl, phosphate groups present on the mycelia provided Fe3+ and K+ binding sites for biosynthesis of jarosite.Xia, Q., Zhang, L., Dong, H., Li, Z., Zhang, Y., Hu, J., Chen, H., Chen, Y., 2020. Bio-weathering of a uranium-bearing rhyolitic rock from Xiangshan uranium deposit, Southeast China. Geochimica et Cosmochimica Acta 279, 88-106. mining and processing has left a serious problem in terms of waste disposal. Microbially mediated U release from crystalline rocks has made the problem even more challenging, but the specific mechanisms for such U release have remained elusive. In this work, bio-weathering experiments of a U-bearing rhyolitic rock were conducted to investigate the rates and mechanisms of microbially-induced U mobilization. Four bacterial isolates from Xiangshan uranium deposit, one of the largest volcanic rock-hosted U deposits worldwide, were able to grow in an oligotrophic medium (OM) in the presence of a U-bearing rhyolitic rock. These bacteria liberated U from the rock through a combination of acidolysis, metabolite-promoted complexation, and oxidative dissolution, among which U mobilization via complexation with citrate was one of the most significant mechanisms. Metabolite secretion was strain-specific, which accounted for the differences in U mobilization efficiency among different bacterial isolates. In particular, Microbacterium sp. 6-1 selectively colonized the surface of U-bearing minerals and mobilized a substantially higher amount of U than other isolates, suggesting a potentially active, mineral-specific attachment and bio-weathering mechanism. Our results demonstrated a high potential and capacity of native microorganisms to mobilize U from U-bearing rock, posing a great challenge for long-term U waste disposal, but also providing an opportunity for U recovery from mine tailings.Xia, Z., Zheng, Y., Stelling, J.M., Loisel, J., Huang, Y., Yu, Z., 2020. Environmental controls on the carbon and water (H and O) isotopes in peatland Sphagnum mosses. Geochimica et Cosmochimica Acta 277, 265-284. conducted a modern process study on Sphagnum magellanicum from southern Patagonian peat bogs to improve our understanding of environmental controls on the carbon and water (hydrogen and oxygen) isotope compositions of peat mosses. We found that moisture availability gradients in peat bogs, measured by Sphagnum water content, could explain the intra-site variability in both Sphagnum cellulose δ13C and δ18O. Also, there was a site-specific significant negative correlation between cellulose δ13C and δ18O across microtopographical gradient. This new finding suggests that Sphagnum moisture availability influences cellulose δ13C via water film effect on discrimination against 13CO2 and, similarly, can imprint on cellulose δ18O via evaporative enrichment of 18O in metabolic leaf water. Sphagnum leaf wax n-alkane δ13C also responded to the water film effect as cellulose did, but n-alkane δ2H appears less sensitive than cellulose δ18O to the moisture availability gradient likely because hydrogen isotopes have a more complex biochemical fractionation pathway and a smaller kinetic fractionation during leaf water evaporation. Furthermore, we used long strands of Sphagnum to explore if isotopic signals in moss strand increments were sensitive to recent growing season conditions. We demonstrated that rapidly growing Sphagnum strand increments could document the isotopic composition of precipitation and moisture conditions at sub-annual scale. Altogether, these findings highlight the sensitivity of stable isotopes in Sphagnum to environmental conditions. On the basis of these results, we propose that paired measurements of carbon and water isotopes in Sphagnum cellulose or leaf wax biomarker provide an improved approach in peat-based paleoclimate reconstructions.Xiao, S., Cui, H., Kang, J., McFadden, K.A., Kaufman, A.J., Kitajima, K., Fournelle, J.H., Schwid, M., Nolan, M., Baele, J.-M., Valley, J.W., 2020. Using SIMS to decode noisy stratigraphic δ13C variations in Ediacaran carbonates. Precambrian Research 343, 105686. carbon isotope (δ13Ccarb) chemostratigraphy is a valuable tool in Precambrian stratigraphic correlation. The effectiveness of this tool rests on the assumption that δ13Ccarb data record global seawater signals. However, in some cases δ13Ccarb data exhibit rapid and noisy stratigraphic variations that may have been influenced by authigenic or diagenetic carbonate minerals. To assess the contribution of non-primary minerals towards bulk carbonate carbon isotope values, we acquired SIMS (secondary ion mass spectrometry) δ13Ccarb data, electron microscopic data, and CL (cathodoluminescence) microscopic data from two Ediacaran successions—the lower Member II of the Doushantuo Formation in South China and the Mooifontein Member of the Zaris Formation in southern Namibia. The Doushantuo samples came from a stratigraphic interval with noisy meter-scale δ13Ccarb variations of up to 10‰, whereas the Mooifontein Member is characterized by consistent δ13Ccarb values with limited meter-scale variations of less than ~4‰. Our data show that the meter-scale stratigraphic variations in δ13Ccarb are also mirrored in the SIMS data at μm-mm scales in both Doushantuo and Mooifontein samples. In the Doushantuo samples, SIMS δ13Ccarb values of authigenic calcite vary by up to 10‰ over μm-mm scales and can be either higher or lower than those of the co-existing dolomite matrix, which also appears to be affected by authigenic carbonate on the basis of petrographic observation. Bulk-sample δ13Ccarb values measured on powders microdrilled from the same SIMS specimens are within the range of SIMS δ13Ccarb values. Thus, we infer that bulk-sample δ13Ccarb values of Doushantuo samples represent mixtures of different carbonate components. The Doushantuo and Mooifontein SIMS δ13Ccarb data validate the traditional method of using chemostratigraphic consistency to evaluate authigenic/diagenetic alteration, but given that secondary phases may be 13C-enriched relative to matrix carbonate, caution is warranted when taking maximum values to approximate primary chemostratigraphic trends.Xiao, W., Wang, Y., Liu, Y., Zhang, X., Shi, L., Xu, Y., 2020. Predominance of hexamethylated 6-methyl branched glycerol dialkyl glycerol tetraethers in the Mariana Trench: source and environmental implication. Biogeosciences 17, 2135-2148. glycerol dialkyl glycerol tetraethers (brGDGTs) are useful molecular indicators for organic carbon (OC) sources and the paleoenvironment. Their application in marine environments, however, is complicated because of a mixed terrestrial and marine source. Here, we examined brGDGTs in sediments from the Mariana Trench, the deepest ocean without significant terrestrial influence. Our result shows a strong predominance of hexamethylated 6-methyl brGDGT (IIIa′) (73.40±2.39?% of total brGDGTs) and an absence of 5-methyl brGDGTs, different from previously reported soils and marine sediments that comprised both 5-methyl and 6-methyl brGDGTs. This unique feature, combined with high δ13COC (?%), low OC∕TN ratio (6.72±0.84), low branched and isoprenoid tetraether (BIT) index (0.03±0.01), and high acyclic hexa-?∕?pentamethylated brGDGT ratio (7.13±0.98), support that brGDGTs in the Mariana Trench sediments are autochthonous rather than terrestrial products. The compiling of literature data shows that the enhanced fractional abundance of hexamethylated 6-methyl brGDGTs is a common phenomenon in continental margins when the marine influence was intensified. The cross plot of acyclic hexa-?∕?pentamethylated brGDGT ratio and fractional abundance of brGDGT IIIa′ provide a novel approach to distinguish terrestrial and marine-derived brGDGTs.Xie, J., Liu, Y., Jia, T., Pan, L., Fang, Y., Shi, C., Nie, G., Zhang, X., Zou, J.-J., 2020. Regioselective synthesis of methyl-substituted adamantanes for promoting oxidation stability of high-density fuels. Energy & Fuels 34, 4516-4524. fuels have drawn tremendous attention for aerospace vehicles due to their high density and high oxidation stability. Here, we reported a regioselective route to synthesize methyl-substituted adamantanes including 1,3,5-trimethyl-adamantane and 1,3,5,7-tetramethyl-adamantane with single configuration via alkylation of 1,3-dimethyl-adamantane, with yields of ～60 and ～80%, respectively. The reaction kinetics of alkylation has been investigated, and the reaction rate constants and apparent activation energies were calculated based on the experimental kinetic data. The oxidation stability of methyl-substituted adamantane family were first evaluated via pressure differential scanning calorimetry and rapid small-scale oxidation test, and the results indicate that the oxidation stability is correlated to the carbon type available on the molecule in the order of 1,3,5,7-tetramethyl-adamantane > 1,3,5-trimethyl-adamantane > 1,3-dimethyl-adamantane > 1-methyl-adamantane. Notably, 1,3,5,7-tetramethyl-adamantane with four quaternary carbons and no tertiary carbon presents supreme oxidation stability than JP-10 and decalin. Finally, we used 1,3,5,7-tetramethyl-adamantane as an additive and achieved in improving the oxidation stability of JP-10. This work presents methyl-substituted adamantanes as good high-density and high-oxidation-stability fuel components and suggests that methyl groups substituted on tertiary carbon of adamantane has a beneficial effect on improving oxidation stability.Xie, Q., Sun, D., Xia, M., Jia, L., Lu, H., Shi, H., Hou, B., Li, D., 2020. Phase transfer catalyst-assisted reversed-phase dispersive liquid–liquid microextraction for the rapid determination of organic acids in Fischer-Tropsch oil products. Fuel 275, 117882. method prior to using high-performance liquid chromatography (HPLC), named phase transfer catalyst-assisted reversed-phase dispersive liquid–liquid microextraction (PTC-RP-DLLME), was developed for the rapid determination of organic acids in Fischer-Tropsch synthesis (FTS) oil products. This method used sodium hydroxide solution and tetrabutylammonium bromide (TBAB) as an extractant and a disperser respectively, in which the TBAB promoted the dispersion of aqueous NaOH solutions in the organic product, and acted as a hydrogen bond receptor to enhance the extraction of organic acids via hydrogen bond interactions. Under the optimized conditions, the calibration curves in the range of 0.1–30 μg mL?1 showed correlation coefficients (r) of 0.998–0.999. Detection limits (S/N = 3) were ranged from 1.0 to 3.5 ng mL?1. The relative standard deviations of intra-day and inter-day repeatability were in the range of 2.9–5.8 % and 4.1–6.7%, respectively. The recoveries ranged from 85.4% to 105.9%. This developed method was employed for the analysis of organic acids in 6 types of oil products. This work provides an efficient and rapid pretreatment method for acid concentration prior to HPLC, and therefore saves time and cost for the quantitative analysis of FTS oil products. Moreover, precise analysis by application of this method is fairly beneficial to the FT catalyst improvement and industrial equipment material selection, and is rather significant for the proper design of the downstream processing/purification system.Xie, Y., Khishvand, M., Piri, M., 2020. Impact of connate brine chemistry on in situ wettability and oil recovery: Pore-scale experimental investigation. Energy & Fuels 34, 4031-4045. this study, we present the results of micro- and macroscale core-flooding experiments performed on reservoir and outcrop sandstone core samples to investigate the impact of connate brine salinity on wettability and oil recovery. Numerous core samples were fully saturated with connate brines of varying salinities and then subjected to a dynamic wettability restoration (aging) process. The miniature core samples were imaged at high resolutions, and the images were used to measure in situ contact angles and evaluate the wettability alteration. Subsequently, some of the core samples were flooded with identical injection brine to examine the interrelationship between connate brine salinity and oil recovery potentials. The experimental observations demonstrate an ascending trend of initial oil–water contact angles with increases in brine salinity. We believe that brine film thickness, controlled by the DLVO interactions and initial cation-water bridging, is responsible for this wettability sensitivity. The equilibrium wettability state is found to shift toward reduced water-wetness when the connate brine salinity increases, which could be associated with improved oil?mineral bonding at higher salinities. Furthermore, using an ultralow salinity connate brine in the aging process results in a heterogeneous equilibrium wettability state including 46% of weakly water- and neutral-wet pores. It is believed that the ultralow salinity brine preserves stable brine films on some of the pore walls, prevents direct oil?mineral contact, and consequently reduces the degree of wettability alteration during the aging process. The subsequent waterflooding experiments on the aged samples indicated favorable oil recovery from media with heterogeneous equilibrium wettability compared to the weakly oil-wet samples. This was due to the existence of water- and neutral-wet pores that reduced the entry pressures of water-displacing-oil events and enhanced the accessibility of water to the oil-wet pore elements, which in turn improved the oil displacement efficiency.Xin, L., Liu, C., Liu, Y., Huo, E., Li, Q., Wang, X., Cheng, Q., 2020. Thermal decomposition mechanism of some hydrocarbons by ReaxFF-based molecular dynamics and density functional theory study. Fuel 275, 117885. order to investigate the decomposition mechanism of hydrocarbons, pyrolysis processes of 11 typical hydrocarbons (isobutane, isopentane, isohexane, n-butane, n-pentane, n-hexane, cyclobutane, cyclopentane, cyclohexane, benzene and toluene) are performed by using ReaxFF MD and DFT method. The results show that the initial pyrolysis reactions of these hydrocarbons can be divided into two types: homolytic cleavage of C–H bond and C–C bond. The bond dissociation energies of C–H bonds are higher than that of C–C bonds in these hydrocarbons except for toluene. The thermal decomposition rates of branched-chain hydrocarbons are faster than that of straight-chain hydrocarbons. The thermal decomposition rates of chain hydrocarbons gradually increase with the increases of C atom number. The main product molecules of hydrocarbon pyrolysis are H2, CH4, C2H2 and C2H4. The apparent activation energies of 4 hydrocarbons (n-pentane, isohexane, neopentane and cyclopentane) pyrolysis are calculated by the kinetic analysis. In further reactions, CH3, C2H5 and H radicals are collided with hydrocarbons to undergo H-abstraction reactions. The energy barriers of H-abstraction reactions are calculated by DFT.Xu, A., Wang, D., Ding, Y., Zheng, Y., Wang, B., Wei, Q., Wang, S., Yang, L., Ma, L.Z., 2020. Integrated comparative genomic analysis and phenotypic profiling of Pseudomonas aeruginosa isolates from crude oil. Frontiers in Microbiology 11, 519. doi: 10.3389/fmicb.2020.00519. aeruginosa is an environmental microorganism that can thrive in diverse ecological niches including plants, animals, water, soil, and crude oil. It also one of the microorganism widely used in tertiary recovery of crude oil and bioremediation. However, the genomic information regarding the mechanisms of survival and adapation of this bacterium in crude oil is still limited. In this study, three Pseudomonads strains (named as IMP66, IMP67, and IMP68) isolated from crude oil were taken for whole-genome sequencing by using a hybridized PacBio and Illumina approach. The phylogeny analysis showed that the three strains were all P. aeruginosa species and clustered in clade 1, the group with PAO1 as a representitive. Subsequent comparative genomic analysis revealed a high degree of individual genomic plasticity, with a probable alkane degradation genomic island, one type I-F CRISPR-Cas system and several prophages integrated into their genomes. Nine genes encoding alkane hydroxylases (AHs) homologs were found in each strain, which might enable these strains to degrade alkane in crude oil. P. aeruginosa can produce rhamnolipids (RLs) biosurfactant to emulsify oil, which enables their survival in crude oil enviroments. Our previous report showed that IMP67 and IMP68 were high RLs producers, while IMP66 produced little RLs. Genomic analysis suggested that their RLs yield was not likely due to differences at genetic level. We then further analyzed the quorum sensing (QS) signal molecules that regulate RLs synthesis. IMP67 and IMP68 produced more N-acyl-homoserine lactones (AHLs) signal molecules than that of PAO1 and IMP66, which could explain their high RLs yield. This study provides evidence for adaptation of P. aeruginosa in crude oil and proposes the potential application of IMP67 and IMP68 in microbial-enhanced oil recovery and bioremediation.Xu, H., Pan, C., Zeng, L., Huang, W., Zhou, C., Yu, S., Liu, J., Zou, Y., Peng, P.a., 2020. Isothermal confined pyrolysis on source rock and kerogens in the presence and absence of water: Implication in isotopic rollover in shale gases. Scientific Reports 10, 5721. rollover refers to that δ13C value of a gas component decreases with maturity. Its occurrence is closely related to high productivity of shale gas. Isothermal confined pyrolysis experiments (gold capsules) were performed to simulate this phenomenon on whole rock Lucaogou and kerogens Saergan, Wuerhe and Fengcheng in the absence (anhydrous) and presence of added water (hydrous) at 50?MPa, 372?°C and heating duration 0–672?h, corresponding to 0.96–1.85 EASY%Ro. For kerogen Saergan isolated from source rock with hydrogen index (HI) 159?mg/g TOC and 1.10–1.30% Ro equivalent, none of δ13C1, δ13C2 and δ13C3 showed any rollover in both anhydrous and hydrous experiments. For Lucaogou whole rock with HI 856?mg/g TOC and 0.50–0.60%Ro, both δ13C2 and δ13C3 showed rollover in anhydrous experiments while all δ13C1, δ13C2 and δ13C3 showed rollover with greater magnitude in hydrous experiments starting at 1.49–1.64 EASY%Ro. For kerogens Wuerhe and Fengcheng isolated from source rocks with HI of 550 and 741?mg/g TOC, and 1.18 and 0.96%Ro respectively, both δ13C2 and δ13C3 demonstrated rollover in anhydrous experiments while only δ13C2 showed rollover with minor magnitude in hydrous experiments starting at 1.47–1.53 EASY%Ro. The different effects of water on isotopic rollover among samples Lucaogou, Wuerhe and Fengcheng can be ascribed to rate related isotopic fractionation. Higher generation rate leads to minor isotopic fractionation and rollover magnitude. It was suggested that isotopic rollover likely occurs in a source rock having higher amount of initial retained oil prior to bulk oil cracking and currently within the major stage of oil-cracking to gas (1.50–2.00%Ro).Xu, H., Yu, H., Fan, J., Zhu, Y., Wang, F., Wu, H., 2020. Two-phase transport characteristic of shale gas and water through hydrophilic and hydrophobic nanopores. Energy & Fuels 34, 4407-4420. attempts to characterize shale gas transport in nanopores are not fully successful due to the fact that the presence of water within shale reservoirs is generally overlooked. In addition, shale is known as a wettability-varying (hydrophilic and hydrophobic) rock depending on various components and maturity grades. Herein, toward this end, we performed a comprehensive study about two-phase transport characteristic of shale gas and water through hydrophilic and hydrophobic nanopores by integrating the molecular dynamics (MD) simulations and analytical models. Using MD simulations, we showed that water molecules prefer to accumulate at the walls (water film) in hydrophilic nanopores while form the water cluster at the center region of hydrophobic nanopores, which significantly alters the shale gas transport behavior. For hydrophilic nanopores, the existence of water film weakens the gas–walls collisions (slip effect), resulting in a viscosity dominant transport mechanism. In contrary, shale gas transport in hydrophobic nanopores is mainly contributed by slip effect where the gas–gas collisions (viscosity) is abated by the water cluster. On this basis, we proposed an analytical model to quantitatively depict the shale gas transport behavior in moist nanopores, which is well verified by MD simulations results. Particularly, according to our flow model, the gas transport capacity decreases to only 15% when mixing with 50% water molecules for both hydrophilic and hydrophobic nanopores, which would be greatly overestimated by traditional models neglecting the presence of water molecules. The deep insights gained in this work will further the exploitation and development of shale reservoirs.Xu, J., Martien, J., Gilbertson, C., Ma, J., Amador-Noguez, D., Park, J.O., 2020. Metabolic flux analysis and fluxomics-driven determination of reaction free energy using multiple isotopes. Current Opinion in Biotechnology 64, 151-160. concentrations, fluxes, and free energies constitute the basis for understanding and controlling metabolism. Mass spectrometry and stable isotopes are integral tools in quantifying these metabolic features. For absolute metabolite concentration and flux measurement, 13C internal standards and tracers have been the gold standard. In contrast, no established methods exist for comprehensive thermodynamic quantitation under physiological environments. Recently, using high-resolution mass spectrometry and multi-isotope tracing, flux quantitation has been increasingly adopted in broader metabolism. The improved flux quantitation led to determination of Gibbs free energy of reaction (ΔG) in central carbon metabolism using a relationship between reaction reversibility and thermodynamic driving force. Here we highlight recent advances in multi-isotope tracing for metabolic flux and free energy analysis.Xu, S., Li, H., Wu, H., Xiao, L., Dong, P., Feng, S., Fan, J., 2020. A facile cooling-assisted solid-phase microextraction device for solvent-free sampling of polycyclic aromatic hydrocarbons from soil based on matrix solid-phase dispersion technique. Analytica Chimica Acta 1115, 7-15. analysis of organic pollutants from a complex matrix has attracted significant attention. In this work, we designed and fabricated a facile cooling-assisted solid-phase microextraction device (CA-SPME) that could be used for the solvent-free extraction of volatile and semivolatile compounds from a complex matrix using a commercial SPME probe. Determination of polycyclic aromatic hydrocarbons (PAHs) from soil samples was carried out to evaluate the performance of the designed CA-SPME device. The effects of heating temperature, cooling temperature, extraction time, and moisture content in soil on extraction efficiency were investigated. To enhance the extraction efficiency of the targeted analytes, the matrix solid-phase dispersion technique (MSPD) by grinding soil with silica gels was applied. The results showed that grinding with silica gels promoted the release of PAHs from the soil matrix to the headspace by disrupting the matrix structure, which then facilitated the extraction efficiency. Under optimized conditions, for all of the targeted PAHs, the method exhibited good linearity (40–4000 ng g?1) with regression coefficients (R2) ranging from 0.9586 to 0.9964. The limits of detection and limits of quantification ranged from 4.2 to 8.5 ng g?1 and 14.0–28.5 ng g?1, respectively. Relative standard deviations corresponding to the analysis of spiked soil samples (n = 5) were 8.1–13.4%. The solvent-free analysis of the certified soil sample using the proposed method demonstrated satisfactory results.Xu, W., Zheng, G., Martinelli, G., Ma, X., Fortin, D., Fan, Q., Chen, Z., 2020. Mineralogical and geochemical characteristics of hydrocarbon-bleached rocks in Baiyanggou mud volcanoes, Xinjiang, NW China. Applied Geochemistry 116, 104572. total of 11 rock samples were systematically collected along the main flow of geofluids running on the slope of the Baiyanggou mud volcanic system and analyzed for their mineralogical and chemical compositions as well as for iron species using XRD, XRF and M?ssbauer spectroscopy, respectively. The analytical results clearly indicated spatial variations for most geochemical parameters caused by redox fluctuation processes around the Baiyanggou mud volcanic system. Close to the mud volcanic craters, the bleached greyish rocks mainly contained ferrous iron in chlorite and muscovite (para-Fe2+) with some portion of ferric hydroxide and ferric iron in clay minerals (para-Fe3+), suggesting a strong reducing environment. Further away from the craters, the relative contents of reducing iron species (Fe2+) in the rocks gradually decreased. The reddish rocks did not appear to be greatly influenced by erupting geofluid and contained relatively high contents of para-Fe3+ and ferric iron in hematite (hem-Fe3+). A redox front occurred at a certain distance from the active mud volcanic craters, in which sharp changes of iron-bearing minerals could be tracked. The reducing and weakly alkaline medium contributed to the precipitation of secondary carbonate minerals such as calcite and siderite. Geofluids composed of brackish waters, gases and oils tended to migrate through sandy veins in a clay sequence, faults and fracture networks with relatively high porosity and permeability. Iron speciation of the solid rocks in the seepage areas could therefore be considered a potential indicator for the migration of reducing geofluids including hydrocarbons located underground.Xue, J., Domingo-Almenara, X., Guijas, C., Palermo, A., Rinschen, M.M., Isbell, J., Benton, H.P., Siuzdak, G., 2020. Enhanced in-source fragmentation annotation enables novel data independent acquisition and autonomous METLIN molecular identification. Analytical Chemistry 92, 6051-6059. ionization (ESI) in-source fragmentation (ISF) has traditionally been minimized to promote precursor molecular ion formation, and therefore its value in molecular identification is underappreciated. In-source annotation algorithms have been shown to increase confidence in putative identifications by using ubiquitous in-source fragments. However, these in-source annotation algorithms are limited by ESI sources that are generally designed to minimize ISF. In this study, enhanced in-source fragmentation annotation (eISA) was created by tuning the ISF conditions to generate in-source fragmentation patterns comparable with higher energy fragments generated at higher collision energies as deposited in the METLIN MS/MS library, without compromising the intensity of precursor ions (median loss ≤10% in both positive and negative ionization modes). The analysis of 50 molecules was used to validate the approach in comparison to MS/MS spectra produced via data dependent acquisition (DDA) and data independent acquisition (DIA) mode with quadrupole time-of-flight mass spectrometry (QTOF-MS). Enhanced ISF as compared to QTOF DDA enabled higher peak intensities for the precursor ions (median: 18 times in negative mode and 210 times in positive mode), with the eISA fragmentation patterns consistent with METLIN for over 90% of the molecules with respect to fragment relative intensity and m/z. eISA also provides higher peak intensity as opposed to QTOF DIA for over 60% of the precursor ions in negative mode (median increase: 20%) and for 88% of the precursor ions in positive mode (median increase: 80%). Molecular identification with eISA was also successfully validated from the analysis of a metabolic extract from macrophages. An interesting side benefit of enhanced ISF is that it significantly improved molecular identification confidence with low resolution single quadrupole mass-spectrometry-based untargeted LC/MS experiments. Overall, enhanced ISF allowed for eISA to be used as a more sensitive alternative to other QTOF DIA and DDA approaches, and further, it enabled the acquisition of ESI TOF and ESI single quadrupole mass spectrometry instrumentation spectra with improved molecular identification confidence.Yan, H., Dettman, D.L., Chen, J., Shen, N., 2020. δ13C in Corbicula fluminea shells: Implication for? dissolved inorganic carbon reconstruction. Geochemical Journal 54, 71-79. Stable isotope ratio measurements of dissolved inorganic carbon (δ13CDIC) provide a useful indication of carbon sources, sinks and fluxes in river ecosystems. Because of the incorporation of dissolved inorganic carbonate during shell growth, shells of aquatic mollusks have the potential to record DIC information and to be a proxy for δ13CDIC in this environment. In our study, specimens of the bivalve mollusk Corbicula fluminea (the Asian freshwater clam) were reared under laboratory conditions and δ13Cshell and δ13CDIC values were measured. It was found that the δ13Cshell values of C. fluminea reared in three tanks which were provided with isotopically distinct foods differed significantly and that all values were more negative than would be obtained under equilibrium fractionation conditions; this is probably because of metabolic effects. In order to estimate the percentage of metabolically-derived carbon in the shell carbonate (CM), δ13Cfood was used as a proxy for the δ13C of metabolic carbon. CM values in the three different tanks were 35%, 49% and 44%, respectively. These proportions are larger than those reported in previous studies. We suggest that the most probable cause is the auto-correlation between δ13Cfood and δ13CDIC. Despite the significant incorporation of metabolic carbon into shell carbonate, our experimental results showed that δ13Cshell was highly correlated with δ13CDIC, following this relationship: δ13CDIC = 0.86 δ13Cshell + 1.57 (R2 = 0.99). A shell collected in 2007 from a river monitored for δ13CDIC shows good agreement between back-calculated and measured δ13CDIC values for the summer of 2006. We suggest that the δ13Cshell of Corbicula fluminea is a promising qualitative proxy of large-scale variations in δ13CDIC in the river environment.Yan, H., Liu, C., An, Z., Yang, W., Yang, Y., Huang, P., Qiu, S., Zhou, P., Zhao, N., Fei, H., Ma, X., Shi, G., Dodson, J., Hao, J., Yu, K., Wei, G., Yang, Y., Jin, Z., Zhou, W., 2020. Extreme weather events recorded by daily to hourly resolution biogeochemical proxies of marine giant clam shells. Proceedings of the National Academy of Sciences 117, 7038-7043.: Reconstructing past extreme weather events, such as tropical cyclones and cold surges, using natural paleoclimate archives can lengthen the instrumental data and help us have a broader understanding of the range of weather variability not evident in instrumental record. However, the time resolution of current paleoarchives, from millennial to monthly at best, is usually too low to explore past weather events. Here we found that the Tridacna shells from South China Sea, western Pacific, have continuous daily growth bands, and several daily to hourly resolution biogeochemical proxy records were developed. Our results demonstrate that these records can record nearby tropical cyclones and cold surges, indicating that Tridacna shells have the potential to be an unprecedented ultra-high-resolution archive for paleoweather reconstructions.Abstract: Paleoclimate research has built a framework for Earth’s climate changes over the past 65 million years or even longer. However, our knowledge of weather-timescale extreme events (WEEs, also named paleoweather), which usually occur over several days or hours, under different climate regimes is almost blank because current paleoclimatic records rarely provide information with temporal resolution shorter than monthly scale. Here we show that giant clam shells (Tridacna spp.) from the tropical western Pacific have clear daily growth bands, and several 2-y-long (from January 29, 2012 to December 9, 2013) daily to hourly resolution biological and geochemical records, including daily growth rate, hourly elements/Ca ratios, and fluorescence intensity, were obtained. We found that the pulsed changes of these ultra-high-resolution proxy records clearly matched with the typical instrumental WEEs, for example, tropical cyclones during the summer?autumn and cold surges during the winter. When a tropical cyclone passes through or approaches the sampling site, the growth rate of Tridacna shell decreases abruptly due to the bad weather. Meanwhile, enhanced vertical mixing brings nutrient-enriched subsurface water to the surface, resulting in a high Fe/Ca ratio and strong fluorescence intensity (induced by phytoplankton bloom) in the shell. Our results demonstrate that Tridacna shell has the potential to be used as an ultra-high-resolution archive for paleoweather reconstructions. The fossil shells living in different geological times can be built as a Geological Weather Station network to lengthen the modern instrumental data and investigate the WEEs under various climate conditions.Yan, L., Aslannejad, H., Hassanizadeh, S.M., Raoof, A., 2020. Impact of water salinity differential on a crude oil droplet constrained in a capillary: Pore-scale mechanisms. Fuel 274, 117798. water flooding can be effectively used for enhanced oil recovery. Given the complex physical and chemical processes involved, several controlling mechanisms have been proposed to describe oil re-mobilization in the presence of water solution with low salinity. Osmosis and water-in-oil emulsification are among these mechanisms. However, our current knowledge about these processes is limited and their associated time scales are not well understood.In this study, we have used 11 capillary tubes with an inner diameter of 800 ?m to inject a sequence of low-salinity water, crude oil, and high-salinity water phases and to observe the evolution of the system. The monitoring was done for a period of 40 days. We used two setups, a CMOS camera and a confocal laser scanning microscopy, to capture dynamics of the oil droplet re-mobilization as well as the 2D/3D water–oil interfaces. Additionally, microscopic pore pressures were directly measured at both low and high-salinity water phases containing the oil droplet using two fiber-optic sensors.We observed that in the water-wet capillaries the oil droplet moved a distance of about 524 ?m. The contact angles at both low and high-salinity water interfaces with crude oil gradually decreased by 34.32° and 18.23°, respectively, during the first 15 days. We found that the pressure difference between high/low-salinity water phases reached a plateau with a maximum value of 1.65 kPa during a period of 24 days. Further, based on these changes and their time scales, we propose a hypothesis about emulsification and water diffusion through the oil phase.Yang, L., Nie, H., Zhao, F., Song, S., Meng, Y., Bai, Y., Liu, H., 2020. A novel online two-dimensional supercritical fluid chromatography/reversed phase liquid chromatography–mass spectrometry method for lipid profiling. Analytical and Bioanalytical Chemistry 412, 2225-2235. novel online two-dimensional supercritical fluid chromatography/reversed-phase liquid chromatography–triple-quadrupole mass spectrometry (2D SFC/RPLC–QQQ MS) method based on a vacuum solvent evaporation interface was developed for lipid profiling in human plasma, in which lipid classes were separated by the first-dimension SFC and different lipid molecular species were further separated by the second-dimension RPLC. All separation condition parameters were carefully optimized, and their influence on the chromatographic behavior of lipids is discussed. Finally, the recoveries of 11 lipid standards were all more than 88% for the interface. Besides, the limit of detection for these lipid standards was on the order of nanograms per milliliter, and the relative standard deviations of the peak area and retention time ranged from 1.54% to 19.85% and from 0.00% to 0.10%, respectively. The final 2D SFC/RPLC–QQQ MS method allowed the identification of 370 endogenous lipid species from ten lipid classes, including diacylglycerol, triacylglycerol, ceramide, glucosylceramide, galactosylceramide, lactosylceramide, sphingomyelin, acylcarnitine, phosphatidylcholine, and lysophosphatidylethanolamine, in human plasma within 38 min, which was used for screening potential lipid biomarkers in breast cancer. The 2D SFC/RPLC–QQQ MS method is a potentially useful tool for in-depth studies focused on complex lipid metabolism and biomarker discovery.Yang, L., Yang, Y., Wang, S., Guan, X., Guan, X., Wang, G., 2020. Multi-heteroatom-doped carbon materials for solid-state hybrid supercapacitors with a superhigh cycling performance. Energy & Fuels 34, 5032-5043. the purpose of assembling high-performance solid-state hybrid supercapacitors (HSCs) with superior cycling stability and energy density, biomass-derived multi-heteroatom-doped carbon materials were prepared in this work and utilized as negative electrodes for the supercapacitors. The applied biomass in this study included orange peel and egg white; besides, we also prepared Ag-doped egg white as a precursor through a denaturation reaction to synthesize a Ag-nanoparticle-decorated carbon material; the consequently obtained carbon materials were referred to as OC, EC, and Ag–EC, respectively. The as-synthesized heteroatom-doped carbon materials displayed excellent electrochemical performance. The specific capacitance retentions were 101.7, 105.4, and 107.4% for OC, EC, and Ag–EC, respectively, after 50?000 cycles. In addition, a core–shell structured C/N–CoO@CoO/NiO nanomaterial was also synthesized and used as the positive electrode, which exhibited a high cycling stability of 111.6% after cycling for 50?000 times. The three corresponding solid-state hybrid supercapacitors (HSCs) possessed excellent energy densities of 33.1, 30.1, and 35.6 Wh kg–1 at about 850.0 W kg–1, respectively. After cycling for 50?000 times, their specific capacitance retentions were 145.9, 139.2, and 140.0%, respectively.Yang, X., Yan, D., Li, T., Zhang, L., Zhang, B., He, J., Fan, H., Shangguan, Y., 2020. Oceanic environment changes caused the Late Ordovician extinction: evidence from geochemical and Nd isotopic composition in the Yangtze area, South China. Geological Magazine 157, 651-665. Ordovician–Silurian (O–S) transition was a critical interval in geological history. Multiple geochemical methods are used to explore the changes in oceanic environment. The Nd isotopic compositions in the Yangtze Sea are controlled by two sources: the continental erosion and the Panthalassa Ocean. High εNd(t) values during the Katian, late Hirnantian and Rhuddanian intervals are associated with the high sea level, which resulted in less terrestrial input based on the low Ti/Al and Zr/Al ratios. In contrast, low εNd(t) values during the early Hirnantian interval are related to the sea-level fall; in this case, the exposure of submarine highs and the growth of Yangtze Oldlands could lead to more continental materials being transported into the Yangtze Sea based on high Ti/Al and Zr/Al ratios. In addition, the negative εNd(t) excursion can also be attributed to the weak circulation between the Yangtze Sea and Panthalassa Ocean when sea level was low. Furthermore, the sea-level eustacy plays a significant role in the changes in redox water conditions. The redox indices, mainly UEF, Ce/Ce* and Corg/PT, across the O–S transition show a predominance of anoxic ocean over the Yangtze Sea during the Katian, late Hirnantian and Rhuddanian intervals, and an oxygenated episode was briefly introduced during the early Hirnantian period because of the fall in sea level. The Late Ordovician biotic crisis was marked by two-phase extinction events, and the change in sea level and redox chemistry may be the important kill mechanisms.Yang, Z., Mirnaghi, F., Shah, K., Lambert, P., Hollebone, B., Yang, C., Brown, C.E., Thomas, G., Grant, R., 2020. Source identification and evolution of oils recovered from the MV Manolis L shipwreck. Fuel 271, 117684. 1985, the MV Manolis L ran aground and sank on Blow Hard Rock near the Change Islands in Notre Dame Bay, Newfoundland and Labrador. From 2013 to 2016, the Canadian Coast Guard (CCG) conducted several operations to trap and recover oil leaking from the sunken tanker. Seventeen samples were collected between 2013 and 2016 from the sunken vessel to identify the oil source and evaluate the evolution of the physicochemical properties of the oil trapped in the sunken vessel. Most of the oils collected in 2016 and all the oils collected from 2013 to 2015 were heavy fuel oils that had not undergone significant weathering (Group 1). Two oils collected in 2016 were identified as diesel oil in terms of their hydrocarbon composition (Group 2). Other two oils collected in 2016 (Group 3) had similar hydrocarbon properties as Group 1 heavy fuel oils; however, they had greater quantities of biomarkers and GC-detectable total petroleum hydrocarbons (TPH) in the >n-C34 fraction and a lower quantity of resolved components, such as n-alkanes and PAHs. Detailed chemical fingerprinting pointed to these samples as being heavy fractions of Group 1 oils that had settled into a residual layer or had weathered through evaporation loss. Neither the heavy fuel oil nor diesel oil experienced significant loss through photo-oxidation and biodegradation, even 31 years post-sinking. Physical deposition, evaporation, and/or dissolution, especially deposition, were the main factors altering the physicochemical properties of the heavy fuel oil trapped in the sunken vessel.Ye, H., Liu, B., Wang, Q., How, Z.T., Zhan, Y., Chelme-Ayala, P., Guo, S., El-Din, M.G., Chen, C., 2020. Comprehensive chemical analysis and characterization of heavy oil electric desalting wastewaters in petroleum refineries. Science of The Total Environment 724, 138117. quantities of highly polluted point-source wastewaters (EDWs) are generated from electric desalting process of heavy oils (HOs), resulting in severe impacts on the efficiency of wastewater treatment plants in petroleum refineries. In the present study, a comprehensive chemical analysis and characterization of EDWs of two typical Chinese heavy oils, Liaohe heavy oil (LHO) and Karamy heavy oil (KHO), were investigated using Daqing light oil (DLO) as a control. The HO-EDWs (LHO-EDW and KHO-EDW) show high pollutants contents with complicated compositions, more polar dissolved organic pollutants (DOPs), strong emulsion stability and high acute biotoxicity towards Vibrio fischeri, compared to DLO-EDW. LHO-EDW and KHO-EDW have nearly equal pollutants contents but different compositions and distributions, where more types of DOPs exist in KHO-EDW. Large amounts of biologically recalcitrant aromatic compounds, as well as heteroatomic compounds such as CHO, CHOS and CHON species, extensively distribute in HO-EDWs. The organic nitrogen compounds (e.g., anilines and N2–3Ox, N1OxS1) in KHO-EDW most probably contribute to and thus leading to elevated levels of acute biotoxicity. Additionally, highly dispersed colloidal, micron-sized particles and polar compounds promote the emulsification and stabilization of HO-EDWs. These results can guide the development of pretreatment technologies for HO-EDWs, thus improving the treatment and management of heavy oil refineries' wastewater streams.Yesufu-Rufai, S., Rücker, M., Berg, S., Lowe, S.F., Marcelis, F., Georgiadis, A., Luckham, P., 2020. Assessing the wetting state of minerals in complex sandstone rock in-situ by Atomic Force Microscopy (AFM). Fuel 273, 117807. salinity waterflooding is a low-cost method of enhancing oil recovery although, no consistent concept has been established explaining why some oil-fields show an increase in oil production when the salinity of the injected brine is reduced, while others do not. Various studies were conducted investigating the underlying mechanisms of the ‘low salinity effect’ using different crude oil, brine and rock compositions. Core floods of sandstone rock and analyses of molecular interactions using model systems indicate that clay content may play a dominant role. However, the spatial configuration of the sheet-like clay particles, which may vary from rock to rock, complicate comparisons of these model scenarios with reality.In the present study, we report the development of a pre-screening method using Atomic Force Microscopy (AFM) to assess rock-fluid interactions, which has previously only been used either on artificial model systems or minerals from crushed rock, by exploring the capability to operate in-situ in complex rock without crushing. The orientation of clay particles within a pore of an outcrop sandstone, Bandera Brown, was investigated with AFM and these particles were further assessed for changes in adhesion in brines of differing salinity. The results show a decrease in adhesions between CH3-functionalised AFM tips and the rock surface in low salinity brine, predominantly at the clay edges. This demonstrates that the edges of the clay particles, which may pin the oil phase after wettability alteration and therewith prevent oil from getting produced, lose this capacity when exposed to low salinity brine.Yin, J., Hao, F., Wang, Z., Chen, X., Zou, H., 2020. Lacustrine conditions control on the distribution of organic-rich source rocks: An instance analysis of the lower 1st member of the Shahejie Formation in the Raoyang Sag, Bohai Bay Basin. Journal of Natural Gas Science and Engineering 78, 103320. lower 1st Member (Es1L) of the Oligocene Shahejie Formation in the Raoyang Sag, the particularly noteworthy source rock interval in the Jizhong Subbasin, were analyzed with sedimentological and geochemical techniques to describe the distribution of organic-rich source rocks and reveal the lacustrine environment and lake types during source rocks deposition. Results of the Raoyang Sag demonstrate that the organic-rich source rocks are mainly distributed in the north-central region with a maximum thickness of up to 120 m in the Maxi Subsag and gradually decreases to the southern tectonic regions such as Liuxi Subsag. These horizontal and vertical heterogeneities are attributed to depositional environments and lake types during the sedimentary period of the Es1L. Lakes in the Raoyang Sag are generally characterized by saline water during the Es1L deposition. The samples representing the south part of the Raoyang Sag display high pristane/phytane (Pr/Ph), C19/C23 TT, and C24 Tet/C26 TT ratios as well as low gammacerane index, 4-methyl sterane index, and sterane/hopane ratio. These findings suggest that hydrological open lake type has unstable water-column stratification, less reducing bottom water, and significant terrigenous supply. However, the samples representing the north-central part of the Raoyang Sag display high gammacerane index, 4-methyl sterane index, and sterane/hopane ratio as well as low Pr/Ph, C19/C23TT, and C24 Tet/C26 TT ratios. A strong correlation exists between δ13C and δ18O, indicating hydrological closed lake-type with excellent water stratification, anoxic bottom water, and enhanced algae productivity. This lake-type is of great significance for continuing research on organic matter enrichment in the Bohai Bay Basin.Yin, Y., Qu, Z.G., Zhang, T., Zhang, J.F., Wang, Q.Q., 2020. Three-dimensional pore-scale study of methane gas mass diffusion in shale with spatially heterogeneous and anisotropic features. Fuel 273, 117750. methane gas mass diffusion in shale is crucial for estimating gas production. However, shale is a typical ultra-tight porous medium that is characterized by its spatially heterogeneous and anisotropic features. The heterogeneous feature is derived from coexisting components including organic matter (OM), inorganic matter (IM), interparticle pores, microfractures, and bound water; the anisotropic feature is induced by the IM particles appearing in the form of flake-like structure. In this work, a three-dimensional (3D) pore-scale lattice Boltzmann model, which considers above heterogeneous and anisotropic features, is presented to study the methane gas diffusion in the shale. The elementary building block model and quartet structure generation set method are integrated to reconstruct 3D shale structures. Reconstructed shale structures are then characterized in terms of porosity, pore size distribution, and pore connectivity. The results show that the shale diffusivity increases with temperature, porosity, and OM volume fraction, while logarithmically decreasing with the increased pressure. Considering the anisotropic feature, the effective diffusivity parallel to the bedding plane is approximately 1.2–4.2 times higher than that perpendicular to the bedding plane. The microfracture orientation and aperture, compared to the microfracture shape and distribution pattern, play a more important role in determining the effective diffusivity. In contrast, the presence of bound water hampers gas diffusion. In addition, a general formula is proposed to conveniently estimate the diffusivity of isotropic shale, where the influences of temperature, pressure, porosity, OM volume fraction, and water saturation are fully considered.Yoon, H.Y., Jeong, H.J., Cha, J.-Y., Choi, M., Jang, K.-S., Kim, W.-Y., Kim, M.G., Jeon, J.-R., 2020. Structural variation of humic-like substances and its impact on plant stimulation: Implication for structure-function relationship of soil organic matters. Science of The Total Environment 725, 138409., five aromatic monomers, one bearing a long alkyl chain [3-pentadecylphenol (3-PP)], the second bearing a polycyclic aromatic hydrocarbon [dihydroxynaphthalene (DHN)], the third bearing an organic amine [l-3,4-dihydroxyphenylalanine (l-DOPA)], the fourth bearing a carboxylic acid [vanillic acid (VA)], and the fifth bearing a phenol [catechol (CA)] were oxidatively coupled to produce four humic-like substances (3-PP, DHN, l-DOPA, and CA/VA) to mimic the diverse organic architectures of natural humus. Analysis using several methods, including SEM, EPR, elemental analysis, FT-IR-ATR, 13C NMR and anti-oxidant capability, revealed that each of the monomeric structures was well incorporated into the corresponding humic-like substances. Seed germination acceleration and NaCl-involved abiotic stress resistance of Arabidopsis thaliana were then tested to determine whether the different structures resulted in different levels of plant growth stimulation. The l-DOPA, CA/VA and DHN-based materials showed enhanced stimulatory activities compared with no treatment, whereas the effects of the 3-PP-based materials were meager. Interestingly, high-resolution (15?T) ESI FT-ICR mass spectrometry-based van Krevelen diagrams clearly showed that the presence of molecules with H/C and O/C ratios ranging from 0.5 to 1.0 and 0.2 to 0.4, respectively, could be connected with such biological actions. Here, the l-DOPA sample showed the highest content of such molecules, followed by the CA/VA, DHN and 3-PP samples. Next, the ability of l-DOPA and CA/VA products to induce resistance in A. thaliana to a pathogen-related biotic stress was tested to confirm whether the proposed molecular features are associated with multi-stimulatory actions on plants. The expression level of pathogenesis-related protein 1 and inspection of plant morphology clearly revealed that both the l-DOPA and CA/VA products stimulate plants to respond to biotic stresses. Size-exclusion chromatography together with NMR and IR data of both the materials strongly suggests that lignin-like supramolecular assemblages play an important role in versatile biological activities of humus.Yu, E.-J., Lee, K.-S., 2020. Improved method for simultaneous determination of the carbon isotopic composition and concentration of atmospheric CO2 using CF-IRMS. International Journal of Mass Spectrometry 452, 116327. of the concentration and isotopic composition of atmospheric CO2 is essential for the identification of sources and sinks of anthropogenic CO2 and the monitoring of various emission reduction techniques, such as geological CO2 storage. A customized and convenient method was proposed to determine the carbon isotopic composition and concentration of CO2 of air samples simultaneously using a continuous flow-isotope ratio mass spectrometer (CF-IRMS) interfaced with a GasBench II (Thermo Fisher Scientific, Bremen, Germany). Convenient sampling and isotopic analysis were achieved using 12-mL Exetainer vials with open tops, screw caps, and rubber septa for both air sampling and isotopic analysis. The proposed method differs from previously reported methods in several aspects, including the convenience of sampling and analysis, and high accuracy and precision despite small sample consumption. Combined with the Keeling plot technique, this method allows accurate determination of the isotope composition of atmospheric CO2. The proposed technique can be applied in various studies involving the isotopic composition and concentration of CO2, such as diagnosing cancer, tracing of anthropogenic CO2 and monitoring of leakage from subsurface CO2 storage.Yu, Q., Xu, S., Shi, W., Tian, Y., Wang, X., 2020. Mass spectrometry coupled with vacuum thermal desorption for enhanced volatile organic sample analysis. Analytical Methods 12, 1852-1857. spectrometry (MS) has been widely used in the detection of volatile organic compounds (VOCs). Sensitivity can be improved by coupling with appropriate pretreatment technology, such as selective adsorption and desorption of analytes using specific sorbent materials. This paper introduces a modified desorption strategy, which integrates cryotrapping adsorption, vacuum desorption, and thermal desorption. Characterization of the proposed pretreatment method has been carried out on a miniature quadrupole mass spectrometer equipped with an electron impact ionization source. During experiments, VOC samples were first collected by using a Tenax sorbent tube cooled in a drikold cryotrap and then released by heating under vacuum conditions. By using a proper MS inlet, the sorption tube can be rapidly emptied before the desorption of analytes, which greatly improves the sampling efficiency of direct introduction MS analysis and reduces the spectral interference of air background molecules. Effective enrichment of VOCs was achieved in the experiments such that the MS detection sensitivity for toluene was increased by 284 times with a sampling time of 2 min. Furthermore, a rough chromatographic separation effect was observed in the vacuum thermal desorption process, and the proposed sampling strategy also showed good quantitative ability in the direct MS analysis of VOCs.Yuan, D., Wang, W., Liu, C., Xu, L., Fei, H., Wang, X., Shen, M., Wang, S., Wang, M., Zhu, G., 2020. Source, contribution and microbial N-cycle of N-compounds in China fresh snow. Environmental Research 183, 109146. importance and contribution of nitrogen compounds and the related microbial nitrogen cycling processes in fresh snow are not well understood under the current research background. We collected fresh snow samples from 21 cities that 80% are from China during 2016 and 2017. Principal component analysis showed that SO42? were in the first principal component, and N-compounds were the second. Furthermore, the main pollutant ions SO42? and NO3? were from anthropogenic sources, and SO42? contributed (61%) more to the pollution load than NO3? (29%), which were confirmed through a series of precipitation mechanism analysis. We selected five N-cycle processes (consist of oxidation and reduction processes) for molecular biology experiments, including Ammonia-oxidation process, Nitrite-oxidation process, Denitrification process, Anaerobic-ammoxidation process (Anammox) and Dissimilatory nitrate reduction to ammonium process (DNRA). Except ammonia-oxidizing archaeal (AOA) and bacterial (AOB) amoA genes (above 107 copies g?1), molecular assays of key functional genes in various nitrogen conversion processes showed a belowed detection limit number, and AOB abundance was always higher than AOA. The determination of the microbial transformation rate using the 15N-isotope tracer technique showed that the potential rate of five N-conversion processes was very low, which is basically consistent with the results from molecular biology studies. Taken together, our results illustrated that microbial nitrogen cycle processes are not the primary biological processes causing the pollution in China fresh snow.Yuan, Q., Mehmani, Y., Burnham, A.K., Lapene, A., Wendebourg, J., Tchelepi, H.A., 2020. Scaling analysis of coupled compaction, kerogen conversion, and petroleum expulsion during geological maturation. Journal of Petroleum Science and Engineering 192, 107285. is an important property of source rocks with implications on petroleum storage and expulsion. The evolution of porosity over geologic time-scales is controlled by coupled processes such as compaction, geothermal heating, kerogen kinetics, and fluid flow. Basin-scale models used to predict the evolution of porosity contain a large number of interdependent parameters. This poses a significant challenge on numerically solving the complex system of equations in field-scale simulators as well as quantifying the uncertainty induced by each parameter. Our objective is to identify the dominant mechanisms that control porosity evolution using scaling analysis. We develop a single-cell model that, despite simplifications, captures all important processes driving the physics, e.g., thermal, mechanical, chemical, sorption, and multi-phase flow. We then identify a minimum set of dimensionless numbers, each associated with a term in the governing equations, that have first-order impact on porosity evolution during primary and secondary cracking of kerogen. The insights here can be used to reduce the dimensionality of basin-scale models and to quantify uncertainty.Zadjelovic, V., Chhun, A., Quareshy, M., Silvano, E., Hernandez-Fernaud, J.R., Aguilo-Ferretjans, M.M., Bosch, R., Dorador, C., Gibson, M.I., Christie-Oleza, J.A., 2020. Beyond oil degradation: enzymatic potential of Alcanivorax to degrade natural and synthetic polyesters. Environmental Microbiology 22, 1356-1369. marine environments are highly oligotrophic ecosystems populated by well‐established specialized microbial communities. Nevertheless, during oil spills, low‐abundant hydrocarbonoclastic bacteria bloom and rapidly prevail over the marine microbiota. The genus Alcanivorax is one of the most abundant and well‐studied organisms for oil degradation. While highly successful under polluted conditions due to its specialized oil‐degrading metabolism, it is unknown how they persist in these environments during pristine conditions. Here, we show that part of the Alcanivorax genus, as well as oils, has an enormous potential for biodegrading aliphatic polyesters thanks to a unique and abundantly secreted alpha/beta hydrolase. The heterologous overexpression of this esterase proved a remarkable ability to hydrolyse both natural and synthetic polyesters. Our findings contribute to (i) better understand the ecology of Alcanivorax in its natural environment, where natural polyesters such as polyhydroxyalkanoates (PHA) are produced by a large fraction of the community and, hence, an accessible source of carbon and energy used by the organism in order to persist, (ii) highlight the potential of Alcanivorax to clear marine environments from polyester materials of anthropogenic origin as well as oils, and (iii) the discovery of a new versatile esterase with a high biotechnological potential.Zeng, J., Liu, J., Li, W., Leong, Y.-K., Elsworth, D., Guo, J., 2020. Evolution of shale permeability under the influence of gas diffusion from the fracture wall into the matrix. Energy & Fuels 34, 4393-4406. is the most important property that controls the transfer of gas mass across a hierarchy of scales within a shale gas reservoir. When gas diffuses from the fracture wall into the matrix, the gas adsorbs onto shale grains. This adsorption may result in matrix swelling. In previous studies, it is commonly assumed that this swelling is uniform within the matrix. Under this assumption, the impact of the gas diffusion process would be neglectable. In this study, we hypothesize that this uniform swelling assumption is responsible for the inconsistencies between poroelastic solutions and experimental or field observations as reported in the literature. We introduce a volumetric ratio of the gas-invaded volume to the whole matrix volume to quantify the impact of matrix swelling volume expansion on the evolution of shale permeability. The gradual matrix pressure increase in the vicinity of fracture walls leads to local swelling. As the gas invaded zone expands within the matrix, the local effect weakens. When the matrix is completely invaded by the injected gas, a new homogeneous state is achieved, and the local effect ends. We find that the evolution of shale permeability from initial to final homogeneous states is a result of the propagation of the gas invaded area. We apply this approach to generate a series of shale permeability maps. These maps explain experimental observations under a spectrum of conditions from constant confining pressure, to constant average pore pressure, to constant effective stress, and to constant total volume conditions.Zeng, Q., Huang, L., Ma, J., Zhu, Z., He, C., Shi, Q., Liu, W., Wang, X., Xia, Q., Dong, H., 2020. Bio-reduction of ferrihydrite-montmorillonite-organic matter complexes: Effect of montmorillonite and fate of organic matter. Geochimica et Cosmochimica Acta 276, 327-344. matter (OM) is often associated with Fe (hydr)oxides such as ferrihydrite (Fh) in soils and sediments, forming binary Fh-OM complexes. Microbial reduction of Fh results in destabilization of the complexes and mineral/OM transformation. However, little is known about the role of clay minerals in such processes, despite their common co-existence with Fh and OM in natural environments. Here Fh-OM complexes were synthesized in the presence of montmorillonite (SWy-2), forming ternary Fh-(SWy-2)-OM complexes. A metal-reducing bacterium Geobacter sulfurreducens was used to reduce Fh in the complexes under circumneutral pH and anoxic conditions with or without H2 as extra electron donor. Various spectroscopy and mass spectrometry methods were used to monitor the progress of Fh bio-reduction and mineral/OM transformation. Results showed that G. sulfurreducens utilized mineral-bound OM as electron donor and/or carbon source to couple with Fh reduction. Relative to Fh-OM complex, addition of SWy-2 to Fh-OM complex enhanced the bio-reduction extent of Fh by increasing the proportion of bioavailable OM that was weakly bound to SWy-2. However, its effect on the bio-reduction rate was variable. SWy-2 initially decreased the rate, because it spatially separated OM (electron donor) from Fh (electron acceptor). During later incubation, SWy-2 increased the reduction rate by sorbing biogenic Fe2+ that would otherwise passivate the Fh and cell surfaces. Bio-reduction transformed mineral-bound OM to microbial products (e.g. necromass, extracellular polymeric substances), but organic compounds with aromatic structures, carboxyl groups and large molecular weight were more resistant to desorption and oxidation. The persistence of these compounds against bio-reduction induced transformation is likely due to their stronger binding with minerals and/or lower nominal oxidation states of carbon relative to other compounds. Our results provide new insights into the role of clay minerals in regulating biogeochemical cycling of solid-phase Fe and transformation of mineral-associated OM in anoxic soil environments.Zerkle, A.L., Yin, R., Chen, C., Li, X., Izon, G.J., Grasby, S.E., 2020. Anomalous fractionation of mercury isotopes in the Late Archean atmosphere. Nature Communications 11, 1709.’s surface underwent a dramatic transition ~2.3 billion years ago when atmospheric oxygen first accumulated during the Great Oxidation Event, but the detailed composition of the reducing early atmosphere is not well known. Here we develop mercury (Hg) stable isotopes as a proxy for paleoatmospheric chemistry and use Hg isotope data from 2.5 billion-year-old sedimentary rocks to examine changes in the Late Archean atmosphere immediately prior to the Great Oxidation Event. These sediments preserve evidence of strong photochemical transformations of mercury in the absence of molecular oxygen. In addition, these geochemical records combined with previously published multi-proxy data support a vital role for methane in Earth’s early atmosphere.Zhang, H., Diao, R., Chan, H.H., Mostofi, M., Evans, B., 2020. Molecular simulation of the adsorption-induced deformation during CO2 sequestration in shale and coal carbon slit pores. Fuel 272, 117693. swelling induced by CO2 adsorption is a major concern for CO2 sequestration in coal and shale. Deeper insight into the mechanism of adsorption-induced swelling is essential for the CO2 geological storage. In this work, we have used grand canonical Monte Carlo simulation to study the adsorption-induced deformation strain based on the deformable organic carbon slit pore models. In particular, we studied the microstructure and distribution of the adsorbed molecules to obtain the adsorption location effect on swelling. The results showed the deformations of both swelling and shrinkage are sensitive to the pore size. The pores below 0.55 nm have no deformation. The 0.55–0.6 nm pores show the maximum swelling, corresponding to the largest adsorption density. The shrinkage occurs in the 0.65–0.80 nm range depending on pressure and temperature. When the pressure increases, the swelling is enhanced while the shrinkage is mitigated, while the pore size for the maximum swelling or shrinkage remains the same. When the temperature increases, both swelling and shrinkage decrease due to decreased adsorption density. The results showed the CO2 molecules adsorbed in different locations exert heterogeneous solvation pressures across the pore. Generally, the molecules close to pore walls are parallel, tending to swell the pore, which plays a dominant role in the deformation. However, when the pore size increases, some molecules exert a negative solvation pressure, with inclined and vertical orientations, tending to contract the pore although swelling is the total deformation.Zhang, L., Liu, X., Zhao, Y., Zhou, Y., Shan, B., 2020. Effect of pore throat structure on micro-scale seepage characteristics of tight gas reservoirs. Natural Gas Industry B 7, 160-167. present, the effects of pore throat structure on micro-scale seepage characteristics of tight gas reservoirs are less researched, and traditional numerical simulation methods are faced with a great number of challenges in the study of micro-scale flow. In this paper, the flow pattern of tight gas was studied based on the actual temperature and pressure of tight gas reservoir and the characteristic size of reservoir pore throat, and the rationality of tight gas flow was simulated by means of lattice Boltzmann method. Then, considering the influences of micro-scale effect, slippage effect and other factors, a tight gas flow model was established on the basis of LBGK-D2Q9 model, and its calculation results were compared with the analytical solutions and the numerical solutions listed in the literature. Finally, the influential laws of pore throat structure on the micro-scale seepage characteristics of tight gas were discussed. And the following research results were obtained. First, when the pressure is in the range of 3–70 MPa and the temperature is in the range of 293.15–373.15 K, the Knudsen number (Kn) is less than 0.1 and the gas flow is in the pattern of slippage flow and weak continuous flow. And in this case, it is reasonable to adopt the LBGK-D2Q9 model to simulate tight gas flow. Second, the effect of the characteristic size of the flow channel on the Kn is much greater than that of the pressure change. When the pore–throat ratio is constant, the Kn increases slowly along the throat. And its increasing trend gets more obvious with the increase of pore–throat ratio. Third, the presence of the throat makes the non-linear distribution characteristics of the pressure in the pore throat significant, and the pressure drop mainly lies in the throat. And the higher the pore–throat ratio is, the larger the pressure drop range in the throat is. Fourth, the non-linear distribution of pressure decreases the gas flow speed significantly, thus reducing the mass flow rate in the flow channel. In conclusion, the simulation result of the model established in this paper is highly coincident with the analytical solutions and the numerical solutions calculated by DSMC and IP methods in the literature, which verifies that this proposed model is reliable. The research results reveal the importance of “connecting fracture and expanding throat” in the practical development engineering of tight gas reservoirs.Zhang, M., Sun, G., Ren, L., Yuan, H., Dong, G., Zhang, L., Liu, F., Cao, P., Ko, A.M.-S., Yang, M.A., Hu, S., Wang, G.-D., Fu, Q., 2020. Ancient DNA evidence from China reveals the expansion of Pacific dogs. Molecular Biology and Evolution 37, 1462-1469. ancestral homeland of Australian dingoes and Pacific dogs is proposed to be in South China. However, the location and timing of their dispersal and relationship to dog domestication is unclear. Here, we sequenced 7,000- to 2,000-year-old complete mitochondrial DNA (mtDNA) genomes of 27 ancient canids (one gray wolf and 26 domestic dogs) from the Yellow River and Yangtze River basins (YYRB). These are the first complete ancient mtDNA of Chinese dogs from the cradle of early Chinese civilization. We found that most ancient dogs (18/26) belong to the haplogroup A1b lineage that is found in high frequency in present-day Australian dingoes and precolonial Pacific Island dogs but low frequency in present-day China. Particularly, a 7,000-year-old dog from the Tianluoshan site in Zhejiang province possesses a haplotype basal to the entire haplogroup A1b lineage. We propose that A1b lineage dogs were once widely distributed in the YYRB area. Following their dispersal to South China, and then into Southeast Asia, New Guinea and remote Oceania, they were largely replaced by dogs belonging to other lineages in the last 2,000?years in present-day China, especially North China.Zhang, P., Lu, S., Li, J., Chang, X., Li, J., Li, W., Chen, G., Wang, S., Feng, W., 2019. Broad ion beam-scanning electron microscopy pore microstructure and multifractal characterization of shale oil reservoir: A case sample from Dongying Sag, Bohai Bay Basin, China. Energy Exploration & Exploitation 38, 613-628. structure and its heterogeneity are critical factors controlling the storage capacity and transportation properties of hydrocarbons. Broad ion-beam-milling scanning-electron microscopy allows for the study of a larger planar at high resolution than other methods and can provide insight into shale microstructures. In this study, we investigate the microscopic pore structure of a shale oil reservoir sample from Paleogene Shahejie Formation in Dongying Sag, Bohai Bay Basin, based on the broad ion-beam cross-section, and discuss the heterogeneity of the major pores using multifractal theory. The representative elementary area of the sample was first inferred to be ～100?×?100??m2 (25 single images) for the broad ion-beam cross-section with an area of 1.054?×?0.915?mm2. Five pore types (interparticle, intraparticle clay, dissolution, inter-crystalline, and organic) were subsequently identified and analyzed in the selected typical representative elementary area. The results showed that interparticle, intraparticle clay, and dissolution pores were the major pore types and made a significant contribution to the total visible surface porosity (98.34%), whereas inter-crystalline and organic pores were not of great importance. Interparticle pores exhibited the most complex pore morphologies, the largest average pore diameter, and the simplest pore structure. Moreover, interparticle pores that were sub-parallel to the bedding plane showed the best connectivity. Intraparticle clay pores, on the other hand, had the smallest average pore diameter, the most complex pore structure, and their distribution in a two-dimensional plane was the most homogeneous. Dissolution pores were characterized by the least complex pore morphologies but more heterogeneous pore distribution. Both intraparticle clay and dissolution pores were abundant but possessed poor connectivity. We conclude that for shale oil storage and transportation in the Dongying Sag, interparticle pores play an important role in shale oil seepage, whereas intraparticle clay and dissolution pores provide the main space for the occurrence of shale oil.Zhang, S., Qiao, W., Wu, Y., Fan, Z., Zhang, L., 2020. Experimental study on seepage characteristics of microfracture with different aperture. Scientific Reports 10, 5452. the flow mechanism of fluid in rock mass is important in solving the water inrush problems during tunnel excavation. However, it is difficult to obtain an undisturbed rock mass from the actual site conditions and study the flow mechanism of fluid through a fracture network composed of multiple single fractures. Therefore, a solution to simulate rock seepage using rock-like samples with single microfracture was presented in this paper. Water flow through microfracture was tested and the deformation of microfracture was recorded by quasi-distributed fiber Bragg grating (FBG) technology. Experimental data showed that Forchheimer’s law and Izbash’s law could well describe the nonlinear relationship between flow velocity and hydraulic gradient. The coefficient b in Forchheimer’s equation decreased with the increase of microfracture aperture. A critical value of E?=?0.8 was proposed to classify the nonlinear flow regime: weak turbulence (E?<?0.8) and fully developed turbulence (E?>?0.8).Zhang, W., Huang, Z., Li, X., Chen, J., Guo, X., Pan, Y., Liu, B., 2020. Estimation of organic and inorganic porosity in shale by NMR method, insights from marine shales with different maturities. Journal of Natural Gas Science and Engineering 78, 103290. porosity system of shale reservoir contains organic pore and inorganic pore, of which the gas adsorption characteristics and wettability properties differ dramatically. In order to conduct estimation of organic pore and inorganic pore in shale reservoir, six marine shale samples were selected to quantify the proportion (vol%) of different pores by using the new method, in which the NMR T2 spectra of samples saturated with deionized water and kerosene were respectively acquired, representing pore size distribution of hydrophilic pore and lipophilic pore correspondingly. The NMR T2 signals of different saturating fluids were introduced to calculate the proportion (vol%) of organic pore and inorganic pore. Further, the observation of argon milled image of shale samples which can give statistical analysis is also conducted accordingly. The results from the two methods are almost in agreement, indicating feasibility of the new method. By using the method in shales with varying maturities, the proportions of organic and inorganic pores of shales in different evolution stages were figured out. Generally, the TOC is positively correlated with organic porosity that almost an organic porosity of 1.51–1.76% (vol.) is provided for per unit TOC (1.0%, wt.) in low-mature shale. And the porosity increase caused by per unit TOC (1.0%, wt.) during organic matter maturation is 2.53–3.41%, while the proportion of inorganic porosity continuously decreases with thermal maturity. From the study, it is significant that the organic porosity and inorganic porosity of shale with given TOC and thermal maturity can be roughly estimated.Zhang, W., Liang, J., Wan, Z., Su, P., Huang, W., Wang, L., Lin, L., 2020. Dynamic accumulation of gas hydrates associated with the channel-levee system in the Shenhu area, northern South China Sea. Marine and Petroleum Geology 117, 104354. on the formation and distribution of submarine channel systems and associated gas-bearing fluids is of great significance for gas hydrate exploration. Disseminated gas hydrates with high saturation up to 65% were recovered from a submarine ridge, equivalent to the levee of the channel–levee system in the Shenhu area, northern South China Sea. Sedimentary deposits in the submarine ridge were dominated by fine-grained silt and clay-rich silt; gas hydrates with relatively high saturation preferentially accumulated in coarser sediments with less clay content. Although abundant foraminifera fossils may have increased reservoir pore space, their presence was not a necessary condition for high-saturation hydrates. Higher levels of pyrite appeared in the reservoirs corresponding to high-saturation hydrates, which suggests that the reducing environment caused by sufficient methane provided adequate gas to form higher-saturation hydrates. Because of the migration of the channel–levee system, different channels formed their respective depositional systems composed of channel-filling, buried channel-filling, erosion grooves, and slumped turbidities. Relatively coarse-grained deposits were identified in the channel fillings and levees, and the accumulation of hydrates was affected by the lithological features of the sediments and their spatial coupling with the gas hydrate stability zone (GHSZ). GHSZ modeling based on in situ measurements indicated that erosion and sedimentation, as well as variations of the geothermal gradient, resulted in the upward/downward migration of bottom simulating reflectors (BSRs). On the erosion flank of the channel, the strata thinned, and rapid erosion was likely to destroy the shallower BSR, causing gas hydrate decomposition and methane release, and may have caused turbidite slumping and seepage, whereas the strata thickened on the deposition flank of the channel. The BSR in the channel–levee system would gradually move toward the new GHSZ, eventually forming a new BSR; parts of the BSR that formed under the original P–T conditions have remained, and double BSRs occurred in the seismic profile. The thermal fluid that moved upward through a gas chimney may also have caused the migration of the GHSZ, resulting in the emergence of double BSRs. During the lateral migration of the channel and the vertical migration of the gas-bearing fluid, there was a dynamic adjustment relationship between the GHSZ and the erosion–deposition process of the channel, resulting in the dynamic accumulation of hydrates in the Shenhu area. A model to demonstrate the relationship between channel migration and variation of the BSR was established, which is of great significance for understanding the formation and accumulation mechanisms of gas hydrates.Zhang, Y.-Y., Zhang, Q., Zhang, Y.-M., Wang, W.-W., Zhang, L., Yu, Y.-J., Bai, C.-C., Guo, J.-Z., Fu, H.-Y., She, Y., 2020. A comprehensive automatic data analysis strategy for gas chromatography-mass spectrometry based untargeted metabolomics. Journal of Chromatography A 1616, 460787. data analysis for gas chromatography-mass spectrometry (GC-MS) is a challenging task in untargeted metabolomics. In this work, we provide a novel comprehensive data analysis strategy for GC-MS-based untargeted metabolomics (autoGCMSDataAnal) by developing a new automatic strategy for performing TIC peak detection and resolution and proposing a novel time-shift correction and component registration algorithm. autoGCMSDataAnal uses original acquired GC-MS datafiles as input to automatically perform TIC peak detection, component resolution, time-shift correction and component registration, statistical analysis, and compound identification. We utilize standards and complex plant samples to comprehensively investigate the performance of autoGCMSDataAnal. The results suggest that the developed strategy is comparable with several state-of-the-art methods that are widely used in GC-MS-based untargeted metabolomics. Based on the proposed strategy, we develop a user-friendly MATLAB GUI for users who are unfamiliar with programming languages to facilitate their routine analysis, which can be freely downloaded at: , Y., Gautam, R., Pandey, S., Omara, M., Maasakkers, J.D., Sadavarte, P., Lyon, D., Nesser, H., Sulprizio, M.P., Varon, D.J., Zhang, R., Houweling, S., Zavala-Araiza, D., Alvarez, R.A., Lorente, A., Hamburg, S.P., Aben, I., Jacob, D.J., 2020. Quantifying methane emissions from the largest oil-producing basin in the United States from space. Science Advances 6, eaaz5120. new satellite observations and atmospheric inverse modeling, we report methane emissions from the Permian Basin, which is among the world’s most prolific oil-producing regions and accounts for >30% of total U.S. oil production. Based on satellite measurements from May 2018 to March 2019, Permian methane emissions from oil and natural gas production are estimated to be 2.7 ± 0.5 Tg a?1, representing the largest methane flux ever reported from a U.S. oil/gas-producing region and are more than two times higher than bottom-up inventory-based estimates. This magnitude of emissions is 3.7% of the gross gas extracted in the Permian, i.e., ~60% higher than the national average leakage rate. The high methane leakage rate is likely contributed by extensive venting and flaring, resulting from insufficient infrastructure to process and transport natural gas. This work demonstrates a high-resolution satellite data–based atmospheric inversion framework, providing a robust top-down analytical tool for quantifying and evaluating subregional methane emissions.Zhang, Y., Huang, X., Wang, R., Naafs, B.D.A., 2020. The distribution of long-chain n-alkan-2-ones in peat can be used to infer past changes in pH. Chemical Geology 544, 119622. (C21-C33) n-alkan-2-ones are biomarkers ubiquitous in peat deposits. However, their paleoenvironmental significance lacks constraints. Here we evaluate the influence pH exerts on the occurrence of long-chain n-alkan-2-ones in Chinese peats. A comparison of the distribution in a collection (n = 65) of modern peat samples with different pH (pH values 4.4–8.6) from China demonstrates that their distribution is significantly different in acid compared to alkaline peat. This difference can be explained by the pH control on the conversion of n-alkan-2-one precursor compounds (n-alkanes and fatty acids). Transfer functions between pH and n-alkan-2-one ratios were established using linear and logarithmic regression models. We then applied these proxies to reconstruct variations of paleo-pH in the Dajiuhu peat sequence to identify the history of peatland acidification over the last 13 kyr. We find significant changes in paleo-pH during the deglaciation/early Holocene and relate these to times of dry climate in the region. The drought-induced peat acidification is supported by observations from modern drying events in the peatland. We propose that long-chain n-alkan-2-ones in peats have potential to trace paleo-pH changes across the deglaciation and Holocene, although further research from different peatlands and time periods is still needed.Zhang, Y., Wei, L., Cui, Z., Zhang, T., Lei, Y., Gu, A., Chen, Y., Zhang, L.Y., Du, Z.X., 2020. Characterizations of palace lantern tassels preserved in The Palace Museum, Beijing, by UPLC-ESI-Q-TOF. Archaeometry 62, 660-676. lanterns were important and highly visible decorations in the imperial palace in Beijing, China, during the Qing dynasty (1636–1912). Most lanterns had colourful tassels made of fibres. The study performed a comprehensive investigation of the materials and dyes used for palace lantern tassels preserved in The Palace Museum, Beijing. Eight samples with different colours, including yellow, green and red, from five palace lanterns were analysed. By using ultra‐performance liquid chromatography combined with time‐of‐flight mass spectrometry, the compositions of the dyes were identified quickly, and thus the dyes' origins were explored. A X‐ray fluorescence spectrometer assisted in the detection of whether a mordant was used during the dyeing process. As a result, the tassels were all made of silk, discovered through the use of microscopic observation and micro‐Fourier transform infrared spectrometry analysis. Different dyeing techniques were found in these tassels: yellow tassels were dyed by cork tree or turmeric by a direct dyeing method; greens were dyed by pagoda bud with an iron mordant, or by the combination of cork tree and indigo using multi‐dyeing method; and red tassels were coloured with different acid red industrial dyes. These results provide valuable data for the conservation of ancient textile tassels and contribute to the investigation of other hanging tags.Zhang, Y., Xiao, X., Liu, D., Wang, E., Liu, K., Ding, Y., Yao, P., Zhao, M., 2020. Spatial and seasonal variations of organic carbon distributions in typical intertidal sediments of China. Organic Geochemistry 142, 103993. zones are the main sites for land-ocean interaction and play an important role in transporting and accumulating organic carbon (OC). Understanding sources and preservation of sedimentary OC are vital to better evaluate the processes controlling the OC distribution in intertidal zones. In this study, we present bulk parameters of total organic carbon (TOC), δ13Corg, grain size and biomarker contents in surface sediments of 14 typical intertidal zones along China’s coastline during both the wet season (WS) and the dry season (DS). Statistical analysis of our data set showed that TOC and biomarker contents were generally high in small estuaries, intermediate but more variable in large estuaries and low in non-estuaries; and these distribution patterns broadly correlated with sedimentary clay contents. TOC and biomarker contents were generally higher in the WS than the DS reflecting both OC inputs and preservation. A binary mixing model based on δ13Corg and biomarker proxies revealed that large estuaries were characterized by higher terrestrial OC fractions (62–80%) except for the Yellow River Estuary (24%), while lower terrestrial OC fractions occurred in non-estuaries (13–15%). Variable OC contributions were found in small estuaries, with most sites characterized by low terrestrial OC contributions (3–35%), but high terrestrial OC contributions were found at the Qiantang River Estuary site (59%) and the Jiulong River Estuary site (67%). Carbon stocks in Chinese intertidal sediments are comparable with those in marine sediments from shelf areas and the Exclusive Economic Zone (EEZ). This study suggests that intertidal sediments are potentially an important carbon sink.Zhang, Z., Liu, H., Wang, J., 2020. Energetics of interfacial interactions of hydrocarbon fluids with kerogen and calcite using molecular modeling. Energy & Fuels 34, 4251-4259. of the fluid–rock interactions is essential to characterize the behavior of petroleum fluids in reservoir formations. Such knowledge is difficult to obtain due to the heterogeneous nature of hydrocarbon systems. This study investigated the interactions of light oil molecules with kerogen and calcite using molecular dynamics simulations. Specifically, octane and octanthiol were used as model molecules for non-polar and polar oil compounds; a kerogen fragment molecule was employed as the building block for kerogen, the major constituent of reservoir rock organics; calcite was used as a model system for hydrophilic materials in reservoir rocks. Umbrella sampling method combined with the weighted histogram analysis method was deployed to calculate the free energy profiles of oil molecule interactions with kerogen and calcite surfaces. The effects of surface composition, oil molecular polarity, surface water, and size of the oil molecular cluster on the interfacial interactions were evaluated based on the free energy profiles. The results show that the minimal energy required to recover oil molecules significantly decreases at both kerogen and calcite surfaces if water is presented. The kerogen surface exhibits stronger binding energies with oil molecules than that of the calcite. These findings suggest that (1) polar oil compounds require more effort to be recovered from the reservoir rocks than non-polar molecules, (2) isolated oil molecules or oil clusters of a smaller size are harder to be displaced from the surfaces than a larger size of molecular clusters, and (3) the presence of water reduces the effort to recover oil at both surfaces. The results provide an energetic perspective of the interfacial interactions for the oil recovery in reservoir formations. This study demonstrates the capability of MD simulations in evaluating the energetics of the oil–rock interactions under different interface conditions, which can provide valuable implications for developing novel technologies of oil recovery.Zhao, C., Shi, M., Feng, Q., Ye, Y., Zareen Khan, M., Feng, F., 2020. New study of microbial mats from the Mesoproterozoic Jixian Group, North China: Evidence for photosynthesis and oxygen release. Precambrian Research 344, 105734. mats were well established and widespread during the Proterozoic eon, playing a pivotal role in atmospheric oxygen content. In this study, microbial mats were systematically investigated from the 1600 Ma to 1400 Ma Jixian Group, North China. Three types of microbial mats were recognized, including Microbial Mat dominated by Filaments (MMF), Microbial Mat dominated by Coccoids (MMC), Microbial Mat dominated by Filaments and Coccoids (MMFC). These microbial mats were mainly built by Siphonophycus kestron, Siphonophycus solidum, Myxococcoides sp. and Coniunctiophycus majorinum. Due to in situ preservation, five sedimentary structures related to photosynthesis and oxygen release were discovered in these microbial mats. The alternating light-dark laminae and bottleneck structure may be caused by immediate mineralization and phototropism of filaments in a hypersaline environment. Bubble structure, fenestrae structure and hourglass structure probably were related to oxygen release, and their emergence fill the gap between oxygenic photosynthesis of microbial mat and atmospheric oxygen content in Proterozoic eon.Zhao, R., Dahle, H., Ramírez, G.A., J?rgensen, S.L., 2020. Indigenous ammonia-oxidizing archaea in oxic subseafloor oceanic crust. mSystems 5, e00758-19.: Oceanic ridge flank systems represent one of the largest and least-explored microbial habitats on Earth. Fundamental ecological questions regarding community activity, recruitment, and succession in this environment remain unanswered. Here, we investigated ammonia-oxidizing archaea (AOA) in the sediment-buried basalts on the oxic and young ridge flank at North Pond, a sediment-filled pond on the western flank of the Mid-Atlantic Ridge, and compared them with those in the overlying sediments and bottom seawater. Nitrification in the North Pond basement is thermodynamically favorable and is supported by a reaction-transport model simulating the dynamics of nitrate in the crustal fluids. Nitrification rate is estimated to account for 6% to 7% of oxygen consumption, which is similar to the ratios found in marine oxic sediments, suggesting that aerobic mineralization of organic matter is the major ammonium source for crustal nitrifiers. Using the archaeal 16S rRNA and amoA genes as phylogenetic markers, we show that AOA, composed solely of Nitrosopumilaceae, are the major archaeal dwellers at North Pond. Phylogenetic analysis reveals that the crustal AOA communities are distinct from those in the bottom seawater and the upper oxic sediments but are similar to those in the basal part of the overlying sediment column, suggesting either similar environmental selection or the dispersal of microbes across the sediment-basement interface. Additionally, quantitative abundance data suggest enrichment of the dominant Nitrosopumilaceae clade (Eta clade) in the basement compared to the seawater. This study explored AOA and their activity in the upper oceanic crust, and our results have ecological implications for the biogeochemical cycling of nitrogen in the crustal subsurface.Importance: Ridge flanks represent the major avenue of chemical and heat exchange between the Earth’s oceans and the lithosphere and are thought to harbor an enormous and understudied biosphere. However, little is known about the diversity and functionality of the crustal biosphere. Here, we report an indigenous community of archaea specialized in ammonia oxidation (i.e., AOA) in the oxic oceanic crust at North Pond. These AOA are the dominant archaea and are likely responsible for most of the cycling taking place in the first step of nitrification, a feasible nitrogen cycling step in the oxic basement. The crustal AOA community structure significantly differs from that in deep ocean water but is similar to that of the community in the overlying sediments in close proximity. This report links the occurrence of AOA to their metabolic activity in the oxic subseafloor crust and suggests that ecological selection and in situ proliferation may shape the microbial community structure in the rocky subsurface.Zhao, R., Summers, Z.M., Christman, G.D., Yoshimura, K.M., Biddle, J.F., 2020. Metagenomic views of microbial dynamics influenced by hydrocarbon seepage in sediments of the?Gulf of Mexico. Scientific Reports 10, 5772. cells in the seabed are thought to persist by slow population turnover rates and extremely low energy requirements. External stimulations such as seafloor hydrocarbon seeps have been demonstrated to significantly boost microbial growth; however, the microbial community response has not been fully understood. Here we report a comparative metagenomic study of microbial response to natural hydrocarbon seeps in the Gulf of Mexico. Subsurface sediments (10–15?cm below seafloor) were collected from five natural seep sites and two reference sites. The resulting metagenome sequencing datasets were analyzed with both gene-based and genome-based approaches. 16S rRNA gene-based analyses suggest that the seep samples are distinct from the references by both 16S rRNA fractional content and phylogeny, with the former dominated by ANME-1 archaea (~50% of total) and Desulfobacterales, and the latter dominated by the Deltaproteobacteria, Planctomycetes, and Chloroflexi phyla. Sulfate-reducing bacteria (SRB) are present in both types of samples, with higher relative abundances in seep samples than the references. Genes for nitrogen fixation were predominantly found in the seep sites, whereas the reference sites showed a dominant signal for anaerobic ammonium oxidation (anammox). We recovered 49 metagenome-assembled genomes and assessed the microbial functional potentials in both types of samples. By this genome-based analysis, the seep samples were dominated by ANME-1 archaea and SRB, with the capacity for methane oxidation coupled to sulfate reduction, which is consistent with the 16S rRNA-gene based characterization. Although ANME-1 archaea and SRB are present in low relative abundances, genome bins from the reference sites are dominated by uncultured members of NC10 and anammox Scalindua, suggesting a prevalence of nitrogen transformations for energy in non-seep pelagic sediments. This study suggests that hydrocarbon seeps can greatly change the microbial community structure by stimulating nitrogen fixation, inherently shifting the nitrogen metabolism compared to those of the reference sediments.Zhao, Z., Baltar, F., Herndl, G.J., 2020. Linking extracellular enzymes to phylogeny indicates a predominantly particle-associated lifestyle of deep-sea prokaryotes. Science Advances 6, eaaz4354. prokaryotes express extracellular hydrolytic enzymes to cleave large organic molecules before taking up the hydrolyzed products. According to foraging theory, extracellular enzymes should be cell associated in dilute systems such as deep sea habitats, but secreted into the surrounding medium in diffusion-limited systems. However, extracellular enzymes in the deep sea are found mainly dissolved in ambient water rather than cell associated. In order to resolve this paradox, we conducted a global survey of peptidases and carbohydrate-active enzymes (CAZymes), two key enzyme groups initiating organic matter assimilation, in an integrated metagenomics, metatranscriptomics, and metaproteomics approach. The abundance, percentage, and diversity of genes encoding secretory processes, i.e., dissolved enzymes, consistently increased from epipelagic to bathypelagic waters, indicating that organic matter cleavage, and hence prokaryotic metabolism, is mediated mainly by particle-associated prokaryotes releasing their extracellular enzymes into diffusion-limited particles in the bathypelagic realm.Zhou, H., Zhang, S., Xie, J., Wei, H., Hu, Z., Wang, H., 2020. Pyrene biodegradation and its potential pathway involving Roseobacter clade bacteria. International Biodeterioration & Biodegradation 150, 104961. mineralization plays a significant role in the removal of polycyclic aromatic hydrocarbons (PAHs) from polluted environments. Bacteria affiliated to the Roseobacter clade are ubiquitous and abundant in various environments, including PAH-polluted areas. However, very little is known about the PAH degradation mechanism utilized by the Roseobacter clade. In this study, eight bacterial strains belonging to the Roseobacter clade were isolated from sediments collected from the estuary of the Pearl River. Degradation of pyrene and two other typical PAHs (phenanthrene and benzo[a]pyrene) was studied in the eight isolated strains of Roseobacter clade bacteria (RCB) and three other type strains. The results revealed that all strains had low PAH-degrading efficiency when PAHs were used as the sole source of carbon. However, upon supplementation with an alternative carbon source, the degradation was greatly stimulated. This implies that RCB degrade PAHs via a co-metabolism pathway. A putative pyrene degradation pathway in RCB was re-constructed based on genomic analysis. pahE, a functional marker gene for PAH degradation, was detected in the genomes of RCB. PAH ring-hydroxylating dioxygenase alpha subunit domain family and beta subunit domain family and PAH degradation-related Rieske [2Fe–2S] domain were also identified in the test strains. These findings provide fundamental evidence that RCB are capable of degrading PAHs through a versatile metabolic pathway.Zhou, Y., Wu, X., Xiang, R., Xing, L., 2020. Decadal to interdecadal variability in TEX86 temperature on the inner shelf of the East China Sea over the last 3.7 kyr. Organic Geochemistry 142, 104000. understand the long-term environmental evolution of the East China Sea (ECS) and adjacent areas, the variation in TEX86H-derived sea surface temperature (SST) at site T08 collected from the mud area on the inner continental shelf of the ECS over the last 3725?years was reconstructed. The core-top TEX86H SST is 23.2?°C, close to the annual mean SST (22.9?°C) at site T08. The branched and isoprenoid tetraether (BIT) index, which is a proxy for soil organic matter, ranges from 0.029 to 0.059, indicating that the influence of terrestrial input on the TEX86H SST proxy is negligible. The ratio between glycerol dialkyl glycerol tetraethers (GDGTs) GDGT-0 and GDGT-5 (R0/5), which is used to indicate the contribution of methanogenic archaea to the GDGT pool, varies between 0.04 and 0.62, suggesting a minor influence of methanogens on the TEX86H proxy. During the past 3725?years, variation in TEX86H SST can be divided into three periods with an overall increasing trend. During Period I (3725–2500?yr BP), TEX86H SST ranged from 19.0 to 20.6?°C with a mean of 20.1?°C. The values were generally relatively low but with marked fluctuation, attributed to increased input of cold coastal water caused by a strengthened East Asian winter monsoon (EAWM) and a weakened Kuroshio Current (KC). During Period II (2500–750?yr BP), after a low-temperature period at 2400–2200?yr BP, TEX86H SST increased gradually from 19.2 to 23.5?°C. During this period, an intensified East Asian summer monsoon (EASM) and a strengthened KC and Taiwan Warm Current (TWWC) transported warm water from low-latitude areas to ECS coastal areas. During Period III (750?yr BP to present), TEX86H SST increased gradually and reached a maximum (24.2?°C) at ～565?yr BP. Subsequently, TEX86H SST decreased and reached a low value (21.9?°C) at ～279?yr BP. During the period (<750?yr BP), higher TEX86H SST values were caused mainly by intensified KC, whereas lower values corresponded to the Little Ice Age. Spectral analysis reveals that variation in TEX86H SST exhibits periodicities of 175, 80, and 68?years, consistent with the periodicities of solar activity.Zhu, C., Cui, X., He, Y., Kong, L., Sun, Y., 2020. Extended 3β-methylhopanes up to C45 in source rocks from the Upper Cretaceous Qingshankou Formation, Songliao Basin, northeast China. Organic Geochemistry 142, 103998.β-Methylhopanes, methylated at the C-3 position of the A-ring, have been detected ubiquitously in sedimentary rocks with carbon numbers of C28 and C30–C36. These compounds have been attributed to aerobic methanotrophs due to their strongly 13C-depleted compositions. Here we report 3β-methylhopanes with carbon numbers up to C45 in source rocks from the first member of the Upper Cretaceous Qingshankou Formation, Songliao Basin, northeast China. The extended homologues up to C45 might be derived from long-chain alkyl bacteriohopanetetrols by consecutive enzymatic additions of a C5 sugar. Extremely 13C-depleted compositions, combined with a high 3β-methylhopane index, suggest an intense CH4 cycle induced by blooms of aerobic methanotrophs in the Songliao paleo-lake.Zhu, L., Zhang, C., Zhang, Z., Zhou, X., 2020. High-precision calculation of gas saturation in organic shale pores using an intelligent fusion algorithm and a multi-mineral model. Advances in Geo-Energy Research 4, 135-151. gas reservoirs have been the subject of intensifying research in recent years. In particular, gas saturation has received considerable attention as a key parameter reflecting the gas-bearing properties of reservoirs. However, no mature model exists for calculating the saturation of shale gas reservoirs due to the difficulty in calculating the gas saturation. This paper proposes a new gas saturation prediction method that combines model-driven and data-driven approaches. A multi-mineral petrophysical model is applied to derive the apparent saturation model. Using the calculated apparent saturation, matrix parameters and porosity curve as inputs, an intelligent fusion algorithm composed of five regression algorithms is employed to predict the gas saturation. The gas saturation prediction results in the Yongchuan block, Sichuan Basin, reveal that the model proposed in this paper boasts good reliability and a greatly improved prediction accuracy. The proposed model can greatly assist in calculating the gas saturation of shale gas reservoirs.Zhuravlev, A.Y., Wood, R., 2020. Dynamic and synchronous changes in metazoan body size during the Cambrian Explosion. Scientific Reports 10, 6784. aspects of the drivers for, and evolutionary dynamics of, the Cambrian Explosion are poorly understood. Here we quantify high-resolution changes in species body size in major metazoan groups on the Siberian Platform during the early Cambrian (ca. 540–510 Million years ago (Ma)). Archaeocyath sponges, hyolith lophophorates, and helcionelloid mollusc species show dynamic and synchronous trends over million-year timescales, with peaks in body size during the latest Tommotian/early Atbadanian and late Atdabanian/early Botoman, and notably small body sizes in the middle Atdabanian and after the Sinsk anoxic extinction event, starting ca. 513?Ma. These intervals of body size changes are also mirrored in individual species and correlate positively with increased rates of origination and broadly with total species diversity. Calcitic brachiopods (rhynchonelliformeans), however, show a general increase in body size following the increase in species diversity through this interval: phosphatic brachiopods (linguliformeans) show a body size decrease that negatively correlates with diversity. Both brachiopod groups show a rapid recovery at the Sinsk Event. The synchronous changes in these metrics in archaeocyath, hyoliths and helcionelloids suggest the operation of external drivers through the early Cambrian, such as episodic changes in oxygenation or productivity. But the trends shown by brachiopods suggests a differing physiological response. Together, these dynamics created both the distinct evolutionary record of metazoan groups during the Cambrian Explosion and determined the nature of its termination.Ziemiański, P.P., Derkowski, A., Szczurowski, J., Kozie?, M., 2020. The structural versus textural control on the methane sorption capacity of clay minerals. International Journal of Coal Geology 224, 103483. the natural, high-pressure environments of sediments and sedimentary rocks, clay minerals, along with organic matter, contribute to a large portion of the available surface area and microporosity in which methane (CH4) can be adsorbed. However, most of the questions concerning the location of adsorption sites, e.g. interlayer accessibility for CH4, remain unknown. Here, we have separately investigated the textural and structural control on CH4 high-pressure adsorption on pure clay minerals by combining high- and low-pressure gas adsorption techniques, transmission electron microscopy, and thermogravimetric and X-ray diffraction analyses on various cationic forms of montmorillonite, beidellite, and two illites, with different contents of adsorbed water. The results show that CH4 adsorption capacity is controlled by N2-accesible micropore volume. CH4 adsorption sites are located mainly outside of the interlayer galleries unless they are open wide enough (e.g. pillared by organic cations or incompletely dried divalent cations). However, the structure-independent factors like the crystallite planar dimensions and the way that they assemble are the main control on CH4 adsorption capacity. This might be the reason for the inconsistencies in CH4 adsorption reported for clay minerals in the literature. CO2 adsorption measurements, assumed to provide a good proxy for the estimation of CH4 adsorption capacity in natural mudrocks, may overestimate the CH4 adsorption potential in geomaterials containing a significant amount of exchangeable divalent cations due to higher penetrability of CO2 than CH4 in the interlayers of expandable clay minerals.Zito, P., Podgorski, D.C., Bartges, T., Guillemette, F., Roebuck, J.A., Spencer, R.G.M., Rodgers, R.P., Tarr, M.A., 2020. Sunlight-induced molecular progression of oil into oxidized oil soluble species, interfacial material, and dissolved organic matter. Energy & Fuels 34, 4721-4726. oil is highly susceptible to sunlight-induced transformations, both as films on the surface of water and material dissolved or dispersed in the water column. We utilized ultrahigh-resolution mass spectrometry and optical spectroscopy to understand shifts in oil photoproduct distributions as a function of photo-oxygenation. Oxygenation of oil produces compounds that have increased polarity, resulting in greater partitioning to the oil–water interface and eventually greater partitioning into the aqueous phase. Such partitioning was shown to be dependent on the carbon number and oxygen content of the photoproducts, providing an empirical basis for predicting the partitioning of oil photodegradation products between the oil phase, the interfacial region, and into the aqueous phase to form petroleum-derived dissolved organic matter. While such photochemical transformations have been predicted for many years, there has not been direct evidence previously for the photodissolution process. Furthermore, the relationship of carbon number and oxygen content with progression from the oil phase to the interfacial phase to the aqueous phase has not been demonstrated. This paper details this progression and observable properties that can be used to understand oil behavior after a spill during sunlight exposure, thus providing greater predictability of oil fate, transport, impact, and effective remediation strategies.Züllig, T., Tr?tzmüller, M., K?feler, H.C., 2020. Lipidomics from sample preparation to data analysis: a primer. Analytical and Bioanalytical Chemistry 412, 2191-2209. are amongst the most important organic compounds in living organisms, where they serve as building blocks for cellular membranes as well as energy storage and signaling molecules. Lipidomics is the science of the large-scale determination of individual lipid species, and the underlying analytical technology that is used to identify and quantify the lipidome is generally mass spectrometry (MS). This review article provides an overview of the crucial steps in MS-based lipidomics workflows, including sample preparation, either liquid–liquid or solid-phase extraction, derivatization, chromatography, ion-mobility spectrometry, MS, and data processing by various software packages. The associated concepts are discussed from a technical perspective as well as in terms of their application. Furthermore, this article sheds light on recent advances in the technology used in this field and its current limitations. Particular emphasis is placed on data quality assurance and adequate data reporting; some of the most common pitfalls in lipidomics are discussed, along with how to circumvent them.Zumberge, J.A., Rocher, D., Love, G.D., 2020. Free and kerogen-bound biomarkers from late Tonian sedimentary rocks record abundant eukaryotes in mid-Neoproterozoic marine communities. Geobiology 18, 326-347. biomarker assemblages preserved within the bitumen and kerogen phases of sedimentary rocks from the ca. 780–729 Ma Chuar and Visings? Groups facilitate paleoenvironmental reconstructions and reveal fundamental aspects of emerging mid‐Neoproterozoic marine communities. The Chuar and Visings? Groups were deposited offshore of two distinct paleocontinents (Laurentia and Baltica, respectively) during the Tonian Period, and the rock samples used had not undergone excessive metamorphism. The major polycyclic alkane biomarkers detected in the rock bitumens and kerogen hydropyrolysates consist of tricyclic terpanes, hopanes, methylhopanes, and steranes. Major features of the biomarker assemblages include detectable and significant contribution from eukaryotes, encompassing the first robust occurrences of kerogen‐bound regular steranes from Tonian rocks, including 21‐norcholestane, 27‐norcholestane, cholestane, ergostane, and cryostane, along with a novel unidentified C30 sterane series from our least thermally mature Chuar Group samples. Appreciable values for the sterane/hopane (S/H) ratio are found for both the free and kerogen‐bound biomarker pools for both the Chuar Group rocks (S/H between 0.09 and 1.26) and the Visings? Group samples (S/H between 0.03 and 0.37). The more organic‐rich rock samples generally yield higher S/H ratios than for organic‐lean substrates, which suggests a marine nutrient control on eukaryotic abundance relative to bacteria. A C27 sterane (cholestane) predominance among total C26–C30 steranes is a common feature found for all samples investigated, with lower amounts of C28 steranes (ergostane and crysotane) also present. No traces of known ancient C30 sterane compounds; including 24‐isopropylcholestanes, 24‐n‐propylcholestanes, or 26‐methylstigmastanes, are detectable in any of these pre‐Sturtian rocks. These biomarker characteristics support the view that the Tonian Period was a key interval in the history of life on our planet since it marked the transition from a bacterially dominated marine biosphere to an ocean system which became progressively enriched with eukaryotes. The eukaryotic source organisms likely encompassed photosynthetic primary producers, marking a rise in red algae, and consumers in a revamped trophic structure predating the Sturtian glaciation. ................
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