Lipus Daniel, Jia Zeyu, Sondermann Megan, Bussert Robert, Bartholomäus Alexander, Yang Sizhong, Wagner Dirk, Kallmeyer Jens
GFZ German Research Centre for Geosciences, Section Geomicrobiology, Potsdam, Germany.
Department of Biological and Chemical Sciences, College of Life Sciences, Thomas Jefferson University, Philadelphia, Pennsylvania, USA.
Environ Microbiome. 2024 Dec 25;19(1):113. doi: 10.1186/s40793-024-00651-9.
The Eger Rift subsurface is characterized by frequent seismic activity and consistently high CO concentrations, making it a unique deep biosphere ecosystem and a suitable site to study the interactions between volcanism, tectonics, and microbiological activity. Pulses of geogenic H during earthquakes may provide substrates for methanogenic and chemolithoautotrophic processes, but very little is currently known about the role of subsurface microorganisms and their cellular processes in this type of environment. To assess the impact of geologic activity on microbial life, we analyzed the geological, geochemical, and microbiological composition of rock and sediment samples from a 238 m deep drill core, running across six lithostratigraphic zones. We evaluated the diversity and distribution of bacterial and archaeal communities. Our investigation revealed a distinct low-biomass community, with a surprisingly diverse archaeal population, providing strong support that methanogenic archaea reside in the Eger subsurface. Geochemical analysis demonstrated that ion concentrations (mostly sodium and sulfate) were highest in sediments from 50 to 100 m depth and in weathered rock below 200 m, indicating an elevated potential for ion solution in these areas. Microbial communities were dominated by common soil and water bacteria. Together with the occurrence of freshwater cyanobacteria at specific depths, these observations emphasize the heterogenous character of the sediments and are indicators for vertical groundwater movement across the Eger Rift subsurface. Our investigations also found evidence for anaerobic, autotrophic, and acidophilic communities in Eger Rift sediments, as sulfur-cycling taxa like Thiohalophilus and Desulfosporosinus were specifically enriched at depths below 100 m. The detection of methanogenic, halophilic, and ammonia-oxidizing archaeal populations demonstrate that the unique features of the Eger Rift subsurface environment provide the foundation for diverse types of microbial life, including the microbial utilization of geologically derived CO and, when available, H, as a primary energy source.
埃格尔裂谷地下的特点是地震活动频繁且一氧化碳浓度持续偏高，这使其成为一个独特的深层生物圈生态系统，也是研究火山活动、构造运动和微生物活动之间相互作用的合适地点。地震期间地质成因的氢气脉冲可能为产甲烷和化学无机自养过程提供底物，但目前对于这种环境下地下微生物及其细胞过程的作用了解甚少。为了评估地质活动对微生物生命的影响，我们分析了取自一个238米深钻孔岩芯的岩石和沉积物样本的地质、地球化学和微生物组成，该钻孔穿过六个岩石地层带。我们评估了细菌和古菌群落的多样性和分布。我们的调查揭示了一个独特的低生物量群落，其古菌种群惊人地多样，有力地支持了产甲烷古菌存在于埃格尔地下的观点。地球化学分析表明，离子浓度（主要是钠和硫酸盐）在50至100米深度的沉积物以及200米以下的风化岩石中最高，表明这些区域的离子溶解潜力较高。微生物群落以常见的土壤和水生细菌为主。这些观察结果与特定深度出现淡水蓝细菌一起，强调了沉积物的异质性，是埃格尔裂谷地下垂直地下水流动的指标。我们的调查还发现了埃格尔裂谷沉积物中存在厌氧、自养和嗜酸群落的证据, 因为硫循环类群如嗜卤硫杆菌和脱硫孢状菌在100米以下深度特别富集。产甲烷、嗜盐和氨氧化古菌种群的检测表明，埃格尔裂谷地下环境的独特特征为多种类型的微生物生命提供了基础，包括微生物利用地质来源的一氧化碳以及在有氢气时将其作为主要能源。
