Seyler Lauren M, Brazelton William J, McLean Craig, Putman Lindsay I, Hyer Alex, Kubo Michael D Y, Hoehler Tori, Cardace Dawn, Schrenk Matthew O
Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts, USA
Blue Marble Space Institute of Science, Seattle, Washington, USA.
mSystems. 2020 Mar 10;5(2):e00607-19. doi: 10.1128/mSystems.00607-19.
Serpentinization is a low-temperature metamorphic process by which ultramafic rock chemically reacts with water. Such reactions provide energy and materials that may be harnessed by chemosynthetic microbial communities at hydrothermal springs and in the subsurface. However, the biogeochemistry mediated by microbial populations that inhabit these environments is understudied and complicated by overlapping biotic and abiotic processes. We applied metagenomics, metatranscriptomics, and untargeted metabolomics techniques to environmental samples taken from the Coast Range Ophiolite Microbial Observatory (CROMO), a subsurface observatory consisting of 12 wells drilled into the ultramafic and serpentinite mélange of the Coast Range Ophiolite in California. Using a combination of DNA and RNA sequence data and mass spectrometry data, we found evidence for several carbon fixation and assimilation strategies, including the Calvin-Benson-Bassham cycle, the reverse tricarboxylic acid cycle, the reductive acetyl coenzyme A (acetyl-CoA) pathway, and methylotrophy, in the microbial communities inhabiting the serpentinite-hosted aquifer. Our data also suggest that the microbial inhabitants of CROMO use products of the serpentinization process, including methane and formate, as carbon sources in a hyperalkaline environment where dissolved inorganic carbon is unavailable. This study describes the potential metabolic pathways by which microbial communities in a serpentinite-influenced aquifer may produce biomass from the products of serpentinization. Serpentinization is a widespread geochemical process, taking place over large regions of the seafloor and at continental margins, where ancient seafloor has accreted onto the continents. Because of the difficulty in delineating abiotic and biotic processes in these environments, major questions remain related to microbial contributions to the carbon cycle and physiological adaptation to serpentinite habitats. This research explores multiple mechanisms of carbon fixation and assimilation in serpentinite-hosted microbial communities.
蛇纹石化作用是一种低温变质过程，在此过程中，超镁铁质岩石与水发生化学反应。这类反应提供了能量和物质，热液泉和地下的化能合成微生物群落可以利用这些能量和物质。然而，栖息于这些环境中的微生物种群所介导的生物地球化学过程尚未得到充分研究，并且由于生物和非生物过程相互重叠而变得复杂。我们将宏基因组学、宏转录组学和非靶向代谢组学技术应用于从海岸山脉蛇绿岩微生物观测站（CROMO）采集的环境样本，该地下观测站由12口井组成，这些井钻入了加利福尼亚海岸山脉蛇绿岩的超镁铁质和蛇纹岩混合体中。通过结合DNA和RNA序列数据以及质谱数据，我们在栖息于蛇纹岩含水层的微生物群落中发现了几种碳固定和同化策略的证据，包括卡尔文-本森-巴斯姆循环、反向三羧酸循环、还原性乙酰辅酶A（acetyl-CoA）途径和甲基营养作用。我们的数据还表明，CROMO的微生物居民在溶解无机碳无法获取的高碱性环境中，将蛇纹石化过程的产物（包括甲烷和甲酸盐）用作碳源。这项研究描述了蛇纹岩影响的含水层中的微生物群落可能通过蛇纹石化产物产生生物量的潜在代谢途径。蛇纹石化作用是一个广泛存在的地球化学过程，发生在海底的大片区域和大陆边缘，那里古老的海底已 accreted 到大陆上。由于难以区分这些环境中的非生物和生物过程，关于微生物对碳循环的贡献以及对蛇纹岩栖息地的生理适应，仍然存在重大问题。这项研究探索了蛇纹岩宿主微生物群落中碳固定和同化的多种机制。 （注：“accreted”这个词在上下文中可能有特定含义，但未给出完整准确的中文释义，这里保留英文供你参考。）
