Hinrichs Kai-Uwe, Hayes John M, Bach Wolfgang, Spivack Arthur J, Hmelo Laura R, Holm Nils G, Johnson Carl G, Sylva Sean P
Deutsche Forschungsgemeinschaft-Research Center Ocean Margins, Department of Geosciences, University of Bremen, P.O. Box 330440, 28334 Bremen, Germany.
Proc Natl Acad Sci U S A. 2006 Oct 3;103(40):14684-9. doi: 10.1073/pnas.0606535103. Epub 2006 Sep 21.
Concentrations and isotopic compositions of ethane and propane in cold, deeply buried sediments from the southeastern Pacific are best explained by microbial production of these gases in situ. Reduction of acetate to ethane provides one feasible mechanism. Propane is enriched in (13)C relative to ethane. The amount is consistent with derivation of the third C from inorganic carbon dissolved in sedimentary pore waters. At typical sedimentary conditions, the reactions yield free energy sufficient for growth. Relationships with competing processes are governed mainly by the abundance of H(2). Production of C(2) and C(3) hydrocarbons in this way provides a sink for acetate and hydrogen but upsets the general belief that hydrocarbons larger than methane derive only from thermal degradation of fossil organic material.
东南太平洋寒冷、深埋沉积物中乙烷和丙烷的浓度及同位素组成，最好的解释是这些气体在原地由微生物产生。乙酸盐还原为乙烷提供了一种可行的机制。丙烷相对于乙烷富含(13)C。其含量与沉积物孔隙水中溶解的无机碳衍生出的第三个碳原子一致。在典型的沉积条件下，这些反应产生的自由能足以支持生长。与竞争过程的关系主要由H(2)的丰度控制。以这种方式产生C(2)和C(3)碳氢化合物为乙酸盐和氢气提供了一个汇，但打破了一种普遍观点，即大于甲烷的碳氢化合物仅来自化石有机物质的热降解。
