Microbial utilization of abiogenic carbon and hydrogen in a serpentinite-hosted system
Microbial utilization of abiogenic carbon and hydrogen in a serpentinite-hosted system
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DOI：
10.1016/j.gca.2012.06.006
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发表时间：
2012-09-01
影响因子：
5
通讯作者：
Butterfield, David A.
中科院分区：
文献类型：
--
作者：
Lang, Susan Q.;Frueh-Green, Gretchen L.;Butterfield, David A.
暴露在海底的地幔岩构成了一个高活性的化学和热系统，其中与海水相互作用产生蛇纹岩对岩石圈冷却，全球地球化学循环和微生物活动具有重要影响。蛇纹岩中的热液活动以迷城热液区（北纬30度，大西洋中脊）为例，在该热液区，下层超镁铁岩中的流体-岩石反应导致高浓度的非生物氢、甲烷、C-2（+）烷烃和甲酸盐。这些系统被认为是早期地球环境的可能类似物，这些环境产生了第一个生化途径。因此，表征当地微生物群落及其与非生物化合物的潜在联系具有特别重要的意义。在这里，我们证明，在活跃的碳酸盐烟囱中，微生物硫酸盐还原是重要的，高达50%的微生物生物量是由地幔碳合成的。相反，在硫酸盐还原最少的地区，地幔碳仅占生物量的10%。我们将这种差异归因于优势微生物物种（迷城甲烷菌目）在硫酸盐还原剂能够促进这种同化作用的地方对甲酸盐或甲烷的更大掺入。迷城的自养群落利用蛇纹石化反应产生的稳定化学产物流和利用非生物成因的地幔碳的能力，为早期生物合成途径可能在类似环境中发展的假设提供了证据。(C)2012爱思唯尔有限公司保留所有权利。
Mantle rocks exposed on the seafloor constitute a highly reactive chemical and thermal system, in which interaction with seawater to produce serpentinite has major consequences for lithospheric cooling, global geochemical cycles, and microbial activity. Serpentinite-hosted hydrothermal activity is exemplified by the Lost City Hydrothermal Field (30 degrees N, Mid-Atlantic Ridge) where fluid-rock reactions in the underlying ultramafic rocks result in high concentrations of abiotic hydrogen, methane, C-2(+) alkanes, and formate. Such systems have been proposed as possible analogs to the Early Earth environments that gave rise to the first biochemical pathways. Thus, characterizing the local microbial communities and their potential link with abiogenic compounds is of particular significance. Here we demonstrate that in active carbonate chimneys where microbial sulfate reduction is important, up to 50% of the microbial biomass is synthesized from mantle carbon. Conversely, mantle carbon contributes only similar to 10% of the biomass in areas with minimal sulfate reduction. We attribute this difference to greater incorporation of formate or methane by the dominant microbial species, the Lost City Methanosarcinales, in locations where sulfate reducers are able to facilitate this assimilation. The ability of autotrophic communities at Lost City to capitalize on the steady stream of chemical products resulting from serpentinization reactions and to utilize abiogenic mantle carbon lend credence to the hypothesis that early biosynthetic pathways could have developed in similar environments. (C) 2012 Elsevier Ltd. All rights reserved.