title: Changes in Concentration and Distribution of Biomarkers in Biodegraded Oils from Dongying Depression, China.
abstract: The alkane fraction of 11 biodegraded oils and five non-biodegraded oils from the Dongying Depression, Bohai Bay Basin, eastern China, were analyzed by gas chromatography-mass spectrometry to investigate the biomarker alteration caused by biodegradation. Results indicated that the concentration of 25-norhopanes was correlated with increased biodegradation. The oil samples showed an increase in the C31 and C32 hopane 22S/(22S + 22R), C29 sterane C2920S/(20S + 20R), and C29ββ/(ββ + αα) thermal maturity parameters in the heavily biodegraded oils. Oleanane was preferentially biodegraded compared with C3017α-hopane, which was preferentially biodegraded compared with C2917α, 21β-norhopane, C30 moretane, and C29 25-norhopane. The selective depletion of C27-C29 steranes followed the order ααα 20R > ααα 20S + αββ 20R > αββ 20S and C27 > C29 > C28, and the diasteranes and C20-C21 steranes were much more resistant to biodegradation than regular C27-C29 steranes. The steranes were generally preferentially biodegraded compared with the hopanes in this study.
authors.affiliation: School of Geoscience, China University of Petroleum, Changjiang west road, 66#, Huangdao district, Qingdao, Shandong, 266580, China. hongczh@163.com.|State Key Laboratory of Petroleum Resources and Prospecting, Faculty of Natural Resources and Information Technology, China University of Petroleum, Beijing, 102249, PR China. hongczh@163.com.
authors.forename: Zhonghong
authors.initials: Z
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Petroleum Resources and Prospecting, Faculty of Natural Resources and Information Technology, China University of Petroleum, Beijing, 102249, PR China.
authors.forename: T-G
authors.initials: TG
authors.lastname: Wang
authors.affiliation: Key Laboratory of Tectonics and Petroleum Resources of Ministry of Education, China University of Geosciences, Wuhan, 430074, China.
authors.forename: Detian
authors.initials: D
authors.lastname: Yan
mesh_terms: D000473:Alkanes / Q000032:analysis / Q000737:chemistry / Q000378:metabolism; D001673:Biodegradation, Environmental; D002681:China; D010578:Petroleum / Q000032:analysis* / Q000382:microbiology*; D013696:Temperature
chemical_list: D000473:Alkanes; D010578:Petroleum
keywords: Biodegradation; Biomarker; Hopane; Sterane; Thermal maturity