气候变化领域集成服务门户(CCPortal): Formation of ethane and propane via abiotic reductive conversion of acetic acid in hydrothermal sediments

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DOI	10.1073/pnas.2005219118
	Formation of ethane and propane via abiotic reductive conversion of acetic acid in hydrothermal sediments
	Song M.; Schubotz F.; Kellermann M.Y.; Hansen C.T.; Bach W.; Teske A.P.; Hinrichs K.-U.
发表日期	2021
ISSN	0027-8424
卷号	118 期号:47
英文摘要	A mechanistic understanding of formation pathways of lowmolecular- weight hydrocarbons is relevant for disciplines such as atmospheric chemistry, geology, and astrobiology. The patterns of stable carbon isotopic compositions (δ13C) of hydrocarbons are commonly used to distinguish biological, thermogenic, and abiotic sources. Here, we report unusual isotope patterns of nonmethane hydrocarbons in hydrothermally heated sediments of the Guaymas Basin; these nonmethane hydrocarbons are notably 13Cenriched relative to sedimentary organic matter and display an isotope pattern that is reversed relative to thermogenic hydrocarbons (i.e., δ13C ethane > δ13C propane > δ13C n-butane > δ13C n-pentane). We hypothesized that this pattern results from abiotic reductive conversion of volatile fatty acids, which were isotopically enriched due to prior equilibration of their carboxyl carbon with dissolved inorganic carbon. This hypothesis was tested by hydrous pyrolysis experiments with isotopically labeled substrates at 350°C and 400 bar that demonstrated 1) the exchange of carboxyl carbon of C2 to C5 volatile fatty acids with 13C-bicarbonate and 2) the incorporation of 13C from 13C-2-acetic acid into ethane and propane. Collectively, our results reveal an abiotic formation pathway for nonmethane hydrocarbons, which may be sufficiently active in organic-rich, geothermally heated sediments and petroleum systems to affect isotopic compositions of nonmethane hydrocarbons. © 2021 National Academy of Sciences. All rights reserved.
英文关键词	Abiotic ethanogenesis; Abiotic propanogenesis; Hydrothermal sediments; Nonmethane hydrocarbons; Volatile fatty acid
语种	英语
scopus关键词	acetic acid; carbon; carbon 13; dissolved inorganic carbon; ethane; organic matter; propane; unclassified drug; volatile fatty acid; abiotic oxidation; Article; concentration (parameter); controlled study; decarboxylation; geochemistry; geothermal energy; hydrothermal sediment; isotope analysis; oxidation; pyrolysis; sediment; synthesis
来源期刊	Proceedings of the National Academy of Sciences of the United States of America
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/250981
作者单位	MARUM - Center for Marine Environmental Sciences, University of Bremen, Bremen, D-28359, Germany; Department of Geosciences, University of Bremen, Bremen, D-28359, Germany; Department of Earth Marine and Environmental Sciences, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3300, United States
推荐引用方式 GB/T 7714	Song M.,Schubotz F.,Kellermann M.Y.,et al. Formation of ethane and propane via abiotic reductive conversion of acetic acid in hydrothermal sediments[J],2021,118(47).
APA	Song M..,Schubotz F..,Kellermann M.Y..,Hansen C.T..,Bach W..,...&Hinrichs K.-U..(2021).Formation of ethane and propane via abiotic reductive conversion of acetic acid in hydrothermal sediments.Proceedings of the National Academy of Sciences of the United States of America,118(47).
MLA	Song M.,et al."Formation of ethane and propane via abiotic reductive conversion of acetic acid in hydrothermal sediments".Proceedings of the National Academy of Sciences of the United States of America 118.47(2021).