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Molecular Records of Primary Producers and Sedimentary Environmental Conditions of Late Permian Rocks in Northeast Sichuan,China

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Journal of China University of Geosciences 2008年第5期19卷 471-480页

作者：阮小燕罗根明胡守志陈峰孙思吴文钧郭巧珍刘国权 State Key Laboratory of Geological Processes and Mineral Resources China University of GeosciencesWuhan 430074 China Faculty of Earth Resources China University of GeosciencesWuhan 430074 China Key Laboratory of Biogeology and Environmental Geology of Ministry of Education China University of GeosciencesWuhan 430074 China

A series of biomarkers were identified in the aliphafic and aromatic fractions of the extracts from Late Permian Dalong （大隆） and Wujiaping （吴家坪） formations in Shangsi （上寺） Section, Northeast Sichuan （四川）, South China, on the basis of the analysis of gas chromatography-mass spectrometry （GC-MC）. The dominance of lower-molecular-weight n-alkanes throughout the profile suggests the dominant contribution of algae and bacteria to the organics preserved in the marine section. Wujiaping Formation is characterized by the elevated contribution from algae as well as other photoautotrophs such as photosynthetic bacteria as shown by the molecular ratios of hopanes to steranes or tricyclic terpanes as well as the ratio of pristane （Pr） and phytane （Ph） to C17 and C18 n-alkanes. This is in accord with the data from the microscopic measurement on the calcareous algae. In contrast, Dalong Formation is featured by enhanced contribution from bacteria and probably terrestrial organics indicated by the enhanced C24 tetracyclic terpanes relative to tricyclic terpanes. The two formations also show a distinct discrimination in sedimentary environmental conditions including redox condition and salinity. The anoxic condition was only found in the middle of the Dalong Formation as shown by the ratios of Pr/Ph and dibenzothiophene to phenanthrene, consistent with the reported data of Mo and U. An enhanced salinity indicated by the homohopane index is observed at the shallow Wujiaping Formation. On the basis of the composition of primary productivity and the redox condition, Dalong Formation is proposed, herein, to be potential hydrocarbon source rocks in the study site. It is notable that the topmost end-Permian is characterized by a large perturbauce in both the redox condition and salinity, with oxic conditions being frequently interrupted by short-term anoxia, likely showing a causal relationship with the episodic biotic crisis across the Permian-Triassic boundary.

关键词： molecular fossil lipid biomarker Late Permian mass extinction geobiology hydrocarbon source rock.

Environmental evolution recorded by lipid biomarkers from the Tawan loess-paleosol sequences on the west Chinese Loess Plateau during the late Pleistocene

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Environmental evolution recorded by lipid biomarkers from th...

The Variation of Microbial(Methanotroph)Communities in Marine Sediments Due to Aerobic Oxidation of Hydrocarbons

中国科学院地质与地球物理研究所第11届（2011年度）学术年会

作者： Fangming Zeng·Shuyuan Xiang·Kexin Zhang·Yulin Lu Institute of Geology and Geophysics,Graduate University, Chinese Academy of Sciences,Box 9825,Beijing 100029,China Faculty of Earth Sciences,State Key Lab of Geological Processes and Mineral Resources,China University of Geosciences,Wuhan 430074,China Development and Research Center,China Geological Survey, Beijing 100037,China

This study provides a reconstruction of the environmental evolution since 128 ka recorded by the lipid biomarkers of the C-C n-alkanes,the C-C n-alkan- 2-ones and the C-C n-alkanols isolated from the Tawan loess section,Northwest *** in paleoenvironment are reconstmcted from the values of the carbon preference index(CPI),the average chain length(ACL), the L/H(ratio of lower-molecular-weight to higher-molecular -weight homologues),the n-alkane C/C ratios,and the n-alkan-2-one C/C *** parameters indicate the dominance of grasses over the west Chinese Loess Plateau(CLP) during the late Pleistocene. Lower values of the CPI and the ACL values,respectively, indicate stronger microbial reworking of organic matter and changes in plant species,which are both indicative of a warmer-wetter ***,the fluctuations of environment recorded in the Tawan section exhibit ten phases that show obvious cycles between warm periods and cold *** study reveals that changes in the biomarker proxies agree well with changes in the magnetic susceptibility and grain size,and it indicates a huge potential for paleoenvironmental reconstructions by using the n-alkan-2-one and n-alkanol proxies.

关键词： Loess lipid biomarker Linxia Late Pleistocene Earth environment

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Journal of Ocean University of China 2021年第3期20卷 553-561页

作者： LI Jing LIU Changling WU Nengyou HE Xingliang HAO Xiluo LI Feng CHEN Ye MENG Qingguo Key Laboratory of Gas Hydrate Ministry of Natural ResourcesQingdao Institute of Marine GeologyQingdao 266071China Laboratory for Marine Mineral Resources Qingdao National Laboratory for Marine Science and TechnologyQingdao 266071China College of Marine Life Science Ocean University of ChinaQingdao 266100China

Methanotrophs in marine sediments and overlying water attenuate the emissions of methane into the atmosphere and thus play an important role for the global cycle of this greenhouse ***,gas released from natural hydrocarbon seeps are not pure methane but commonly mixed ***,how methanotrophic bacteria behave in the co-presence of methane and heavier hydrocarbons remains *** this paper,the bacteria were cultured aerobically in fresh sediment samples(collected from Bohai Bay in eastern China)at 28℃under the atmospheres of pure methane and methane+ethane+propane mixed gas,*** prevailing terrigenous n-alkanes and fatty acids in the original sediment samples varied consistently after incubations,confirming the proceeding of aerobic bacterial *** real-time quantitative PCR assay and sequencing of the 16S rRNA and particulate methane monooxygenase(pmoA)genes revealed the changes of microbe communities to a methanotroph-dominating structure after ***,after incubations the family Methylococcaceae(typeⅠmethanotrophs)became dominant with proportions higher than 40%,whereas Methylocystaceae(typeⅡmethanotrophs)nearly disappeared in all incubated ***-over,the species of methanotrophs from the samples treated with pure methane were dominated by Methylobacter luteus,whereas Methylobacter whittenburyi took the predominant proportion in the samples treated with mixed *** phenomenon suggests that some methanotrophs may also utilize ethane and ***,this study may help to gain a better understanding of the ef-fects and contributions of microbial activities in marine hydrocarbon seep ecosystems.

关键词： methanotroph aerobic oxidation of hydrocarbons sediment incubation lipid biomarker microbial community

Variation in Solvent-Extractable lipids and n-Alkane Compound-Specific Carbon Isotopic Compositions with Depth in a Southern China Karst Area Soil

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Journal of Earth Science 2010年第4期21卷 382-391页

作者：崔景伟黄俊华 Philip A Meyers 黄咸雨李婧婧刘文贵 State Key Laboratory of Petroleum Resources and Prospecting China University of Petroleum(Beijing) State Key Laboratory of Geological Processes and Mineral Resources China University of Geosciences(wuhan) Department of Geological Sciences The University of Michigan Key Laboratory of Biogeology and Environmental Geology of Ministry of Education China University of Geosciences(wuhan)

Because literatures about the lipid compositions of modern soils in karst areas are scarce, we have studied the soil horizons overlying the Heshang （和尚） Cave that has provided paleoclimate records from speleothem lipid contents. Our analysis reveals a series of n-alkanes, free fatty acids, n-alkanols and n-alkan-2-ones distribution and relative abundance changing with the depth, and in which the ratios of the lower molecular weight to higher molecular weight n-alkanes, free fatty acids, n-alkanols and n-alkan-2-ones have a peak at a subsurface depth of 5 to 10 cm. An accompanying peakin 17β（H）, 21β（H）-hop-22（29）-ene （diploptene） and a shift to less negative n-alkane carbon isotopic values also identify this layer in the karst soil. This pattern indicates the existence of a subsurface soil layer in which the microorgan- isms that produce these compounds are espe- cially abundant. The carbon isotopic values of individual plant wax n-alkanes are about 3%0 greater at the base of the 30- to 40-cm soil profile than in the surface layer, probably as a result ofselective microbial degradation of n-alkanes from different primary sources. The lipids and carbon iso- topic values of individual plant wax n-alkanes study of the overlying soil show a strong microbial activity in this karst soil and help in interpreting the lipid compositions and specific carbon isotopic value of n-alkanes of the stalagmites of the Heshang Cave for paleoenvironmental reconstructions.

关键词： lipid biomarker modern soil karst area compound-specific carbon isotopic value n -alkan-2-one.

Detritus Release Process of Kelp Laminariajaponica in a Kelp-Bivalve Polyculture Mesocosm:Ecological and Trophic Implication

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Detritus Release Process of Kelp Laminariajaponica in a Kelp...