Earth and Biosphere Institute, School of Earth and Environment, University of Leeds, UK.
Extremophiles. 2011 Jul;15(4):473-85. doi: 10.1007/s00792-011-0378-z. Epub 2011 May 24.
The microbial ecology associated with siliceous sinters was studied in five geochemically diverse Icelandic geothermal systems. Bacterial 16S rRNA clone libraries were constructed from water-saturated precipitates from each site resulting in a total of 342 bacterial clone sequences and 43 species level phylotypes. In near-neutral, saline (2.6-4.7% salinity) geothermal waters where sinter growth varied between 10 and ~300 kg year(-1) m(-2), 16S rRNA gene analyses revealed very low (no OTUs could be detected) to medium (9 OTUs) microbial activity. The most dominant phylotypes found in these waters belong to marine genera of the Proteobacteria. In contrast, in alkaline (pH = 9-10), meteoric geothermal waters with temperature = 66-96°C and <1-20 kg year(-1)m(-2) sinter growth, extensive biofilms (a total of 34 OTUs) were observed within the waters and these were dominated by members of the class Aquificae (mostly related to Thermocrinis), Deinococci (Thermus species) as well as Proteobacteria. The observed phylogenetic diversity (i.e., number and composition of detected OTUs) is argued to be related to the physico-chemical regime prevalent in the studied geothermal waters; alkaliphilic thermophilic microbial communities with phylotypes related to heterotrophic and autotrophic microorganisms developed in alkaline high temperature waters, whereas halophilic mesophilic communities dominated coastal geothermal waters.
本研究调查了冰岛五个地球化学性质不同的地热系统中与硅质泉华有关的微生物生态学。从每个地点的水饱和沉淀物中构建了细菌 16S rRNA 克隆文库，共获得了 342 个细菌克隆序列和 43 个种水平的类群。在中性、高盐（2.6-4.7%盐度）的地热水中，泉华生长速率在 10 到 300 公斤/年·平方米之间，16S rRNA 基因分析显示微生物活性非常低（未检测到 OTUs）到中等（9 个 OTUs）。在这些水中发现的最主要的类群属于海洋变形菌门的属。相比之下，在碱性（pH = 9-10）、大气降水型地热水中，温度为 66-96°C，泉华生长速率为 <1-20 公斤/年·平方米，在水中观察到广泛的生物膜（总共有 34 个 OTUs），这些生物膜主要由 Aquificae 类（主要与 Thermocrinis 有关）、Deinococci（Thermus 种）以及变形菌门成员组成。观察到的系统发育多样性（即，检测到的 OTUs 的数量和组成）与研究中地热水中普遍存在的物理化学条件有关；在碱性高温水中，形成了与异养和自养微生物有关的嗜碱性嗜热微生物群落，而嗜盐中温微生物群落则主导了沿海地热水。
