The subsurface process of serpentinization creates an extreme environment for microbial life. This environment includes reducing, ultra-basic groundwater that is limited in electron acceptors. Despite these challenging conditions, there is a great deal of potential energy available to support microbial metabolisms both in the anaerobic subsurface and in aerobic surface environments where serpentinization associated groundwater discharges. In this study, the available energy was quantified through the calculation of chemical affinities, A_r, for three sites of active serpentinization in North America: the Tablelands (NL, CAN), The Cedars (CA, USA), and Aqua de Ney (CA, USA). The results showed that A_r values for each reaction were similar for all sites studied; however, the available energy varied a great deal from reaction to reaction. For example, the reaction of carbon monoxide oxidation provided the most energy to the system followed closely by hydrogen oxidation and methanotrophy. Potential microbial metabolisms were tested, simulating surface and subsurface conditions, in a laboratory-based setting using microcosms with materials from each site. During these microcosm experiments, carbon monoxide oxidation was not observed, and there was little evidence of methane oxidation. Unexpectedly, microbial methanogenesis was observed in methane oxidation microcosms using material collected from The Cedars. The microbial production of methane occurred despite the addition of electron acceptors demonstrating the broad tolerance of methanogens at The Cedars for less reducing conditions.

中文翻译：

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评估蛇纹石化的三个陆地地点的地球化学生物能学和微生物代谢：高原（荷兰，加拿大）、雪松（美国加利福尼亚州）和阿奎德内伊（美国加利福尼亚州）

蛇纹石化的地下过程为微生物生命创造了一个极端的环境。这种环境包括减少电子受体有限的超碱性地下水。尽管存在这些具有挑战性的条件，但仍有大量潜在能量可用于支持厌氧地下和有氧地表环境中的微生物代谢，在这些环境中，蛇纹石化与地下水排放相关。在这项研究中，通过计算北美三个活性蛇纹石化位点的化学亲和力A _r来量化可用能量：Tablelands（NL，CAN），Cedars（CA，USA）和 Aqua de Ney（美国加利福尼亚州）。结果表明，一个_[R对于所有研究的位点，每个反应的值都相似；然而，可用能量因反应而异。例如，一氧化碳氧化反应为系统提供了最多的能量，其次是氢氧化和甲烷氧化。在基于实验室的环境中，使用来自每个地点的材料的微观世界，测试了潜在的微生物代谢，模拟地表和地下条件。在这些微观实验中，没有观察到一氧化碳氧化，也几乎没有甲烷氧化的证据。出乎意料的是，使用从雪松收集的材料在甲烷氧化微观世界中观察到微生物产甲烷。