Geochemical and microbiological evidence for a hydrogen-based, hyperthermophilic subsurface lithoautotrophic microbial ecosystem (HyperSLiME) beneath an active deep-sea hydrothermal field
Geochemical and microbiological evidence for a hydrogen-based, hyperthermophilic subsurface lithoautotrophic microbial ecosystem (HyperSLiME) beneath an active deep-sea hydrothermal field
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DOI：
10.1007/s00792-004-0386-3
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发表时间：
2004-04
期刊：
影响因子：
2.9
通讯作者：
K. Takai;T. Gamo;U. Tsunogai;N. Nakayama;H. Hirayama;K. Nealson;K. Horikoshi
中科院分区：
文献类型：
--
作者：
K. Takai;T. Gamo;U. Tsunogai;N. Nakayama;H. Hirayama;K. Nealson;K. Horikoshi
地下微生物群落由地质学和非生物来源的来自地球内部的氢和二氧化碳支持，不仅对地球上原始生命的性质非常感兴趣，而且可能是外星生命的类似物。在这里，我们首次提出了地球化学和微生物学证据，表明在中印度海脊活跃的深海热液区域之下，存在以嗜热甲烷菌为主的高温地下岩石自养微生物生态系统(HyperSLiME)。热液气体成分的地球化学和同位素分析表明，主热液喷口(分别为0.08m m和−13.8pdb)与相邻分叉喷口(分别为0.2m m和−18.5pdb)之间的甲烷浓度和碳同位素组成均不均匀，表明可能存在地下微生物产甲烷作用，至少在排放更多13C亏损甲烷的分流喷口中是如此。流体中极高丰度的岩浆能源，如氢(2.5毫米)，也促进了以氢为基础的岩石自养微生物活动。培养和与培养无关的分子分析表明，甲烷球菌成员在过热水热排放物和烟囱内部以及热球菌成员的其他主要微生物成分中占主导地位。这些结果表明，由产甲烷菌和发酵菌组成的HyperSLiME存在于该构造活动的地下带，有力地支持了氢驱动地下微生物群落的存在。
Subsurface microbial communities supported by geologically and abiologically derived hydrogen and carbon dioxide from the Earth’s interior are of great interest, not only with regard to the nature of primitive life on Earth, but as potential analogs for extraterrestrial life. Here, for the first time, we present geochemical and microbiological evidence pointing to the existence of hyperthermophilic subsurface lithoautotrophic microbial ecosystem (HyperSLiME) dominated by hyperthermophilic methanogens beneath an active deep-sea hydrothermal field in the Central Indian Ridge. Geochemical and isotopic analyses of gaseous components in the hydrothermal fluids revealed heterogeneity of both concentration and carbon isotopic compositions of methane between the main hydrothermal vent (0.08 mM and −13.8‰ PDB, respectively) and the adjacent divergent vent site (0.2 mM and −18.5‰ PDB, respectively), representing potential subsurface microbial methanogenesis, at least in the divergent vent emitting more13C-depleted methane. Extremely high abundance of magmatic energy sources such as hydrogen (2.5 mM) in the fluids also encourages a hydrogen-based, lithoautotrophic microbial activity. Both cultivation and cultivation-independent molecular analyses suggested the predominance ofMethanococcalesmembers in the superheated hydrothermal emissions and chimney interiors along with the other major microbial components ofThermococcalesmembers. These results imply that a HyperSLiME, consisting of methanogens and fermenters, occurs in this tectonically active subsurface zone, strongly supporting the existence of hydrogen-driven subsurface microbial communities.