The lithified oceanic crust, lower crust gabbros in particular, has remained largely unexplored by microbiologists. Recently, evidence for heterogeneously distributed viable and transcriptionally active autotrophic and heterotrophic microbial populations within low‐biomass communities was found down to 750 m below the seafloor at the Atlantis Bank Gabbro Massif, Indian Ocean. Here, we report on the diversity, activity and adaptations of fungal communities in the deep oceanic crust from ~10 to 780 mbsf by combining metabarcoding analyses with mid/high‐throughput culturing approaches. Metabarcoding along with culturing indicate a low diversity of viable fungi, mostly affiliated to ubiquitous (terrestrial and aquatic environments) taxa. Ecophysiological analyses coupled with metatranscriptomics point to viable and transcriptionally active fungal populations engaged in cell division, translation, protein modifications and other vital cellular processes. Transcript data suggest possible adaptations for surviving in the nutrient‐poor, lithified deep biosphere that include the recycling of organic matter. These active communities appear strongly influenced by the presence of cracks and veins in the rocks where fluids and resulting rock alteration create micro‐niches.

中文翻译：

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元组学强调了深海地壳中真菌的多样性，活性和适应性。

微生物学家尚未对石化的洋壳，尤其是下地壳辉长岩进行了广泛的研究。最近，在印度洋亚特兰蒂斯银行加布布隆断块海床以下750 m处发现了低生物量群落中异种分布的有生存能力和转录活性的自养和异养微生物种群的证据。在这里，我们通过结合元条形码分析与中/高通量培养方法，报道了深海地壳中真菌群落的多样性，活动和适应性，其范围约为10到780 mbsf。元条形码和培养表明，活真菌的多样性低，主要与普遍存在的（陆地和水生环境）类群有关。结合元转录组学的生态生理学分析表明，从事细胞分裂，翻译，蛋白质修饰和其他重要细胞过程的活菌和具有转录活性的真菌种群。笔录数据表明，在营养贫瘠的石化深层生物圈中可能存在适应生存的可能，其中包括有机物的循环利用。这些活跃的群落似乎受到岩石中裂缝和静脉的存在的强烈影响，在岩石中，流体和由此产生的岩石蚀变会形成微壁ni。