Active microbial eukaryotes amidst a marine subsurface RNA paleome

During the first RNA-based survey of subsurface eukaryotes in a globally distributed sample collection, we detected metazoan, plant, and diatom rRNA signatures in sediments up to 2.7 million years old. The recovery of RNA from those taxa is consistent with burial in sub-seafloor environments during sedimentation, and subsequent preservation of those nucleic acids. Extensive controls indicate that the recovered RNA does not derive from seawater or aerosol contaminants, supporting the authenticity of an RNA-based subsurface eukaryotic paleome. This paleome has the potential to inform our understanding of environmental conditions at the time of deposition. Within this same dataset, a high diversity of fungi in ocean sediments was found up to 48 meters below seafloor (mbsf) exhibiting statistically significant correlations with total organic carbon (TOC), sulfide, and dissolved inorganic carbon (DIC). We interpret these correlations, together with the uniqueness of fungal profiles in the subsurface, and microscopic observations of filamentous fungi, yeasts, and spores as indicators of subsurface fungal activity

在全球范围内分布的样本收集中，对海底表层真核生物进行的首次基于 RNA 的调查中，我们检测到了来自无脊椎动物、植物和硅藻的 rRNA 签名，这些签名存在于长达 270 万年的沉积物中。从这些物种中恢复 RNA 与其在沉积过程中埋藏在海底环境中的埋藏相一致，并随后保存了这些核酸。广泛的控制措施表明，所恢复的 RNA 并非来源于海水或气溶胶污染物，从而证实了基于 RNA 的海底真核生物古生物群的可靠性。这一古生物群有潜力增进我们对沉积时期环境条件的理解。在同一数据集中，海底沉积物中发现了高多样性的真菌，其分布深度可达海底以下 48 米，这些真菌与总有机碳 (TOC)、硫化物和溶解无机碳 (DIC) 表现出统计学上的显著相关性。我们将这些相关性，结合海底真菌特征的独特性以及丝状真菌、酵母和孢子的显微观察，解释为海底真菌活动的重要指标。