Microbial production of long-chain n-alkanes: Implication for interpreting sedimentary leaf wax signals

doi:10.1016/j.orggeochem.2017.10.005

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	Microbial production of long-chain n-alkanes: Implication for interpreting sedimentary leaf wax signals
	Li, Gaoyuan 1,2; Li, Li 3; Tarozo, Rafael 2; Longo, William M.2; Wang, Karen J.2; Dong, Hailiang 1,4; Huang, Yongsong 2,5
	2018
发表期刊	ORGANIC GEOCHEMISTRY
卷号	115 期号:10 页码:24-31
文章类型	Article
摘要	Relative distributions as well as compound-specific carbon and hydrogen isotope ratios of long-chain C-25 to C-33 n-alkanes in sediments provide important paleoclimate and paleoenvironmental information. These compounds in aquatic sediments are generally attributed to leaf waxes produced by higher plants. However, whether microbes, such as fungi and bacteria, can make a significant contribution to sedimentary long-chain n-alkanes is uncertain, with only scattered reports in the early 1960s to 1970s that microbes can produce long-chain n-alkanes. Given the rapidly expanding importance of leaf waxes in paleoclimate and paleoenvironmental studies, the impact of microbial contribution to long-chain n-alkanes in sediments must be fully addressed. In this study, we performed laboratory incubation of peat-land soils under both anaerobic and aerobic conditions in the absence of light with deuterium-enriched water over 1.5 years and analyzed compound-specific hydrogen isotopic ratios of n-alkanes. Under aerobic conditions, we find n-alkanes of different chain length display variable degrees of hydrogen isotopic enrichments, with short-chain (C-18-C-21) n-alkanes showing the greatest enrichment, followed by long-chain "leaf wax" (C-27-C-31) n-alkanes, and minimal or no enrichment for mid-chain (C-22-C-25) n-alkanes. In contrast, only the shorter chain (C-18 and C-19) n-alkanes display appreciable isotopic enrichment under anaerobic conditions. The degrees of isotopic enrichment for individual n-alkanes allow for a quantitative assessment of microbial contributions to n-alkanes. Overall our results show the microbial contribution to long-chain n-alkanes can reach up to 0.1% per year in aerobic conditions. For shorter chain n-alkanes, up to 2.5% per year could be produced by microbes in aerobic and anaerobic conditions respectively. Our results indicate that prolonged exposure to aerobic conditions can lead to substantial accumulation of microbially derived long-chain n-alkanes in sediments while original n-alkanes of leaf wax origin are degraded; hence caution must be exercised when interpreting sedimentary records of long-chain n-alkanes, including chain length distributions and isotopic ratios. (c) 2017 Elsevier Ltd. All rights reserved.
关键词	Long-chain N-alkanes Leaf-wax Microbial Production Deuterium-enrichment Incubation Compound Specific Hydrogen Isotope Ratios
WOS标题词	Science & Technology ; Physical Sciences
DOI	10.1016/j.orggeochem.2017.10.005
关键词[WOS]	HYDROGEN ISOTOPE RATIOS ; LAKE-SEDIMENTS ; MT. KENYA ; LIPIDS ; BIOMARKERS ; CLIMATE ; RECORDS ; CARBON ; ACIDS ; HYDROCARBONS
收录类别	SCI
语种	英语
WOS研究方向	Geochemistry & Geophysics
WOS类目	Geochemistry & Geophysics
WOS记录号	WOS:000418885600003
引用统计	被引频次：36[WOS] [WOS记录] [WOS相关记录]
文献类型	期刊论文
条目标识符	http://ir.ieecas.cn/handle/361006/5175
专题	加速器质谱中心
作者单位	1.China Univ Geosci, State Key Lab Biogeol & Environm Geol, Beijing 100083, Peoples R China 2.Brown Univ, Dept Earth Environm & Planetary Sci, Providence, RI 02912 USA 3.Tongji Univ, State Key Lab Marine Geol, Shanghai 200092, Peoples R China 4.Miami Univ, Dept Geol & Environm Earth Sci, Oxford, OH 45056 USA 5.Chinese Acad Sci, Inst Earth Environm, Xian 710075, Shaanxi, Peoples R China
推荐引用方式 GB/T 7714	Li, Gaoyuan,Li, Li,Tarozo, Rafael,et al. Microbial production of long-chain n-alkanes: Implication for interpreting sedimentary leaf wax signals[J]. ORGANIC GEOCHEMISTRY,2018,115(10):24-31.
APA	Li, Gaoyuan.,Li, Li.,Tarozo, Rafael.,Longo, William M..,Wang, Karen J..,...&Huang, Yongsong.(2018).Microbial production of long-chain n-alkanes: Implication for interpreting sedimentary leaf wax signals.ORGANIC GEOCHEMISTRY,115(10),24-31.
MLA	Li, Gaoyuan,et al."Microbial production of long-chain n-alkanes: Implication for interpreting sedimentary leaf wax signals".ORGANIC GEOCHEMISTRY 115.10(2018):24-31.

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