The oceanic waters below a depth of 200 m represent, in terms of volume, the largest habitat of the biosphere, harboring approximately 70% of the prokaryotic biomass in the oceanic water column. These waters are characterized by low temperature, increasing hydrostatic pressure, and decreasing organic matter supply with depth. Recent methodological advances in microbial oceanography have refined our view of the ecology of prokaryotes in the dark ocean. Here, we review the ecology of prokaryotes of the dark ocean, present data on the biomass distribution and heterotrophic and chemolithoautotrophic prokaryotic production in the major oceanic basins, and highlight the phylogenetic and functional diversity of this part of the ocean. We describe the connectivity of surface and deep-water prokaryotes and the molecular adaptations of piezophilic prokaryotes to high hydrostatic pressure. We also highlight knowledge gaps in the ecology of the dark ocean's prokaryotes and their role in the biogeochemical cycles in the largest habitat of the biosphere.

中文翻译：

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深海水柱中的原核生物


就体积而言，200 m以下的海洋水域是生物圈最大的栖息地，蕴藏着海洋水体中约70%的原核生物量。这些水域的特点是温度低、静水压力增加以及有机质供应随深度减少。微生物海洋学的最新方法学进展完善了我们对暗海洋中原核生物生态学的看法。在这里，我们回顾了暗海原核生物的生态学，提供了主要海洋盆地的生物量分布以及异养和化能自养原核生物生产的数据，并强调了这部分海洋的系统发育和功能多样性。我们描述了表面和深水原核生物的连通性以及亲压原核生物对高静水压力的分子适应。我们还强调了暗海原核生物生态学方面的知识差距及其在生物圈最大栖息地的生物地球化学循环中的作用。