title: Source characterization of sedimentary organic matter using molecular and stable carbon isotopic composition of n-alkanes and fatty acids in sediment core from Lake Dianchi, China.
abstract: The distribution and compound-specific carbon isotope ratios of n-alkanes and fatty acids in a sediment core (63 cm) collected from Lake Dianchi were examined to investigate organic matter sources in the eutrophic lake. Fatty acids included free and bound fatty acids. The carbon isotope compositions of individual n-alkanes and fatty acids from Lake Dianchi sediments were determined using gas chromatography/isotope ratio mass spectrometry (GC-IRMS). The δ(13)C values of individual n-alkanes (C16-C31) varied between -24.1‰ and -35.6‰, suggesting a dominance of (13)C-depleted n-alkanes that originated from C3 plants and lacustrine algae. Fatty acids from the sediment extracts were analyzed for their abundances and carbon isotopic compositions. Molecular and isotopic evidence indicates that most of the short-chain fatty acids from Lake Dianchi sediment extracts are sourced from intense microbial recycling and resynthesis of organic matter. Long-chain free fatty acids are mainly derived from terrestrial sources. However, long-chain bound fatty acids are sourced from a combination of terrestrial organic matter, bacteria and algae, with the contribution from algal sources higher in the hypereutrophic stage.
authors.affiliation: State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China; Shandong Key Laboratory of Eco-Environmental Science for Yellow River Delta, Binzhou University, Binzhou, Shandong Province 256600, China.
authors.forename: Jidun
authors.initials: J
authors.lastname: Fang
authors.affiliation: State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China. Electronic address: wufengchang@163.com.
authors.forename: Fengchang
authors.initials: F
authors.lastname: Wu
authors.affiliation: State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China.
authors.forename: Yongqiang
authors.initials: Y
authors.lastname: Xiong
authors.affiliation: State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China.
authors.forename: Fasheng
authors.initials: F
authors.lastname: Li
authors.affiliation: State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China.
authors.forename: Xiaoming
authors.initials: X
authors.lastname: Du
authors.affiliation: State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China.
authors.forename: Da
authors.initials: D
authors.lastname: An
authors.affiliation: State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002, China.
authors.forename: Lifang
authors.initials: L
authors.lastname: Wang
mesh_terms: D000473:Alkanes / Q000032:analysis; D002247:Carbon Isotopes / Q000032:analysis; D002681:China; D004784:Environmental Monitoring; D005227:Fatty Acids / Q000032:analysis; D019015:Geologic Sediments / Q000737:chemistry*; D060106:Lakes; D014873:Water Pollutants / Q000032:analysis
chemical_list: D000473:Alkanes; D002247:Carbon Isotopes; D005227:Fatty Acids; D014873:Water Pollutants
keywords: Fatty acids; Lake Dianchi; Sediment; Stable carbon isotopes; n-Alkanes