Wall Kate, Cornell Jennifer, Bizzoco Richard W, Kelley Scott T
Department of Biology, San Diego State University, 5500 Campanile Drive, San Diego, California.
Microbiologyopen. 2015 Apr;4(2):267-281. doi: 10.1002/mbo3.236. Epub 2015 Jan 6.
Fumaroles (steam vents) are the most common, yet least understood, microbial habitat in terrestrial geothermal settings. Long believed too extreme for life, recent advances in sample collection and DNA extraction methods have found that fumarole deposits and subsurface waters harbor a considerable diversity of viable microbes. In this study, we applied culture-independent molecular methods to explore fumarole deposit microbial assemblages in 15 different fumaroles in four geographic locations on the Big Island of Hawai'i. Just over half of the vents yielded sufficient high-quality DNA for the construction of 16S ribosomal RNA gene sequence clone libraries. The bacterial clone libraries contained sequences belonging to 11 recognized bacterial divisions and seven other division-level phylogenetic groups. Archaeal sequences were less numerous, but similarly diverse. The taxonomic composition among fumarole deposits was highly heterogeneous. Phylogenetic analysis found cloned fumarole sequences were related to microbes identified from a broad array of globally distributed ecotypes, including hot springs, terrestrial soils, and industrial waste sites. Our results suggest that fumarole deposits function as an "extremophile collector" and may be a hot spot of novel extremophile biodiversity.
喷气孔（蒸汽喷口）是陆地地热环境中最常见但却最不为人所了解的微生物栖息地。长期以来人们认为这里环境极端不适宜生命存在，但最近样本采集和DNA提取方法的进展发现，喷气孔沉积物和地下水中存在着相当多样的存活微生物。在本研究中，我们运用非培养分子方法，对夏威夷大岛四个地理位置的15个不同喷气孔中的喷气孔沉积物微生物群落进行了探索。略超过一半的喷口产生了足够高质量的DNA用于构建16S核糖体RNA基因序列克隆文库。细菌克隆文库包含属于11个已确认细菌门类和其他7个门类水平系统发育组的序列。古菌序列数量较少，但同样具有多样性。喷气孔沉积物中的分类组成高度异质。系统发育分析发现，克隆的喷气孔序列与从广泛分布于全球的多种生态类型中鉴定出的微生物相关，包括温泉、陆地土壤和工业废弃物场地。我们的结果表明，喷气孔沉积物起到了“嗜极生物收集器”的作用，可能是新型嗜极生物多样性的热点区域。
