The rock-hosted oceanic crustal aquifer is one of the largest habitable volumes on Earth, and it harbors a reservoir of microbial life that influences global-scale biogeochemical cycles. Here, we use time series metagenomic and metatranscriptomic data from a low-temperature, ridge flank environment that is representative of the majority of global hydrothermal fluid circulation in the ocean to reconstruct microbial metabolic potential, transcript abundance, and community dynamics. The data suggest that the microbial community in this subseafloor habitat is motile, chiefly heterotrophic or mixotrophic, and capable of using alternative electron acceptors such as nitrate and thiosulfate, in addition to oxygen. Anaerobic processes are most abundant in subseafloor horizons deepest in the aquifer, furthest from connectivity with the deep ocean, and there was little overlap in the active microbial populations between sampling horizons. Together, our results indicate the microbial community in the North Pond aquifer plays an important role in the oxidation of organic carbon within the crust, and is also metabolically flexible, with the ability to switch from autotrophy to heterotrophy, as well as function under low oxygen conditions. This work highlights the heterogeneity of microbial life in the subseafloor aquifer and provides new insights into biogeochemical cycling in ocean crust.

中文翻译：

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来自冷的，有氧的海底地壳液的时间序列转录组学揭示了运动的，混合营养的微生物群落

岩石托管的海洋地壳含水层是地球上最大的可居住量之一，它拥有影响全球规模生物地球化学循环的微生物生命库。在这里，我们使用来自低温，山脊侧面环境的时间序列宏基因组学和超转录组学数据，该数据代表了海洋中全球大部分热液循环，以重建微生物的代谢潜力，转录本丰度和群落动态。数据表明，该海底生境中的微生物群落是运动的，主要是异养或混养的，除氧外，还能够使用其他电子受体，例如硝酸盐和硫代硫酸盐。厌氧过程在含水层最深的海底地平线中最丰富，离与深海的连通性最远，在采样时间间隔之间，活跃的微生物种群几乎没有重叠。总之，我们的结果表明，北塘含水层中的微生物群落在地壳内有机碳的氧化中起着重要作用，并且在代谢方面也具有灵活性，能够从自养变为异养，并在低氧条件下起作用条件。这项工作凸显了海底含水层中微生物生命的异质性，并为洋壳中生物地球化学循环提供了新见解。具有从自养型转为异养型的能力，并在低氧条件下起作用。这项工作凸显了海底含水层中微生物生命的异质性，并为洋壳中生物地球化学循环提供了新见解。具有从自养型转为异养型的能力，并在低氧条件下起作用。这项工作凸显了海底含水层中微生物生命的异质性，并为洋壳中生物地球化学循环提供了新见解。