Bacterial Communities Associated with Subsurface Geochemical Processes in Continental Serpentinite Springs
Bacterial Communities Associated with Subsurface Geochemical Processes in Continental Serpentinite Springs
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DOI：
10.1128/aem.00330-13
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发表时间：
2013-07-01
影响因子：
4.4
通讯作者：
Schrenk, Matthew O.
中科院分区：
文献类型：
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作者：
Brazelton, William J.;Morrill, Penny L.;Schrenk, Matthew O.
与蛇纹岩化的地球化学过程相关的反应可以产生大量的氢和低分子有机碳化合物，这些化合物可以提供能量和营养，以独立于光合作用支持的表面生物圈维持地下微生物群落。以前的微生物生态学研究已经在深海热液喷口验证了这一假说，例如迷失的城市热液区域。这项研究应用了类似的方法，包括16S rRNA基因的分子指纹和标签序列，来自蛇纹岩作用的超基性大陆泉。这些分子调查与流体的地球化学测量相联系，采用跨学科的方法，旨在区分潜在的地下生物体和来自表面栖息地的生物。在富含氢的地下流体与含氧地表水混合的过渡带中，β蛋白细菌属嗜氢菌被确定为可能的居住者。黑线藻属与指示地下流体的地球化学因素密切相关，并被确定为最有可能居住在蛇纹岩作用驱动的地下生物圈中。这两个分类群都在世界各地的多个富氢地下生境中被发现，这项研究的结果有助于形成一种新的生物地理模式，即BetaProtebacteria出现在近地表混合区，而Firmicut出现在更深的缺氧地下生境中。
Reactions associated with the geochemical process of serpentinization can generate copious quantities of hydrogen and low-molecular-weight organic carbon compounds, which may provide energy and nutrients to sustain subsurface microbial communities independently of the photosynthetically supported surface biosphere. Previous microbial ecology studies have tested this hypothesis in deep sea hydrothermal vents, such as the Lost City hydrothermal field. This study applied similar methods, including molecular fingerprinting and tag sequencing of the 16S rRNA gene, to ultrabasic continental springs emanating from serpentinizing ultramafic rocks. These molecular surveys were linked with geochemical measurements of the fluids in an interdisciplinary approach designed to distinguish potential subsurface organisms from those derived from surface habitats. The betaproteobacterial genus Hydrogenophaga was identified as a likely inhabitant of transition zones where hydrogen-enriched subsurface fluids mix with oxygenated surface water. The Firmicutes genus Erysipelothrix was most strongly correlated with geochemical factors indicative of subsurface fluids and was identified as the most likely inhabitant of a serpentinization-powered subsurface biosphere. Both of these taxa have been identified in multiple hydrogen-enriched subsurface habitats worldwide, and the results of this study contribute to an emerging biogeographic pattern in which Betaproteobacteria occur in near-surface mixing zones and Firmicutes are present in deeper, anoxic subsurface habitats.