Department of Biology, University of Victoria, Petch Building 116, 3800 Finnerty Rd, Victoria, BC, Canada.
Geobiology. 2010 Dec;8(5):417-32. doi: 10.1111/j.1472-4669.2010.00247.x.
Seafloor iron oxide deposits are a common feature of submarine hydrothermal systems. Morphological study of these deposits has led investigators to suggest a microbiological role in their formation, through the oxidation of reduced Fe in hydrothermal fluids. Fe-oxidizing bacteria, including the recently described Zetaproteobacteria, have been isolated from a few of these deposits but generally little is known about the microbial diversity associated with this habitat. In this study, we characterized bacterial diversity in two Fe oxide samples collected on the seafloor of Volcanoes 1 and 19 on the South Tonga Arc. We were particularly interested in confirming the presence of Zetaproteobacteria at these two sites and in documenting the diversity of groups other than Fe oxidizers. Our results (small subunit rRNA gene sequence data) showed a surprisingly high bacterial diversity, with 150 operational taxonomic units belonging to 19 distinct taxonomic groups. Both samples were dominated by Zetaproteobacteria Fe oxidizers. This group was most abundant at Volcano 1, where sediments were richer in Fe and contained more crystalline forms of Fe oxides. Other groups of bacteria found at these two sites include known S- and a few N-metabolizing bacteria, all ubiquitous in marine environments. The low similarity of our clones with the GenBank database suggests that new species and perhaps new families were recovered. The results of this study suggest that Fe-rich hydrothermal sediments, while dominated by Fe oxidizers, can be exploited by a variety of autotrophic and heterotrophic micro-organisms.
海底氧化铁沉积物是海底热液系统的常见特征。对这些沉积物的形态学研究表明，微生物在其形成过程中可能发挥了作用，通过氧化热液中的还原态铁来实现。已经从这些沉积物中的少数几个中分离出了氧化铁的细菌，包括最近描述的 Zetaproteobacteria，但通常人们对与这种生境相关的微生物多样性知之甚少。在这项研究中，我们对取自南汤加弧火山 1 号和 19 号海底的两个氧化铁样本中的细菌多样性进行了描述。我们特别感兴趣的是确认这两个地点是否存在 Zetaproteobacteria，并记录除铁氧化菌以外的其他菌群的多样性。我们的结果（小亚基 rRNA 基因序列数据）显示了惊人的高细菌多样性，有 150 个属于 19 个不同分类群的操作分类单位。两个样本都以 Zetaproteobacteria 铁氧化菌为主导。该组在火山 1 号更为丰富，那里的沉积物富含铁，并且含有更多结晶形式的氧化铁。在这两个地点还发现了其他细菌群，包括已知的 S-和一些 N-代谢细菌，它们在海洋环境中无处不在。我们的克隆与 GenBank 数据库的相似性较低表明，新的物种，也许还有新的科，被重新发现。这项研究的结果表明，富含铁的热液沉积物虽然以铁氧化菌为主导，但可以被各种自养和异养微生物利用。
