Ambrosini Roberto, Musitelli Federica, Navarra Federico, Tagliaferri Ilario, Gandolfi Isabella, Bestetti Giuseppina, Mayer Christoph, Minora Umberto, Azzoni Roberto Sergio, Diolaiuti Guglielmina, Smiraglia Claudio, Franzetti Andrea
Dept. of Earth and Environmental Sciences (DISAT), University of Milano-Bicocca, Piazza della Scienza 1, 20126, Milan, Italy.
Bavarian Academy of Sciences and Humanities, Munich, Germany.
Microb Ecol. 2017 May;73(4):827-837. doi: 10.1007/s00248-016-0914-6. Epub 2016 Dec 21.
Cryoconite holes are small ponds that form on the surface of glaciers that contain a dark debris, the cryoconite, at the bottom and host active ecological communities. Differences in the structure of bacterial communities have been documented among Arctic and mountain glaciers, and among glaciers in different areas of the world. In this study, we investigated the structure of bacterial communities of cryoconite holes of Baltoro Glacier, a large (62 km in length and 524 km of surface) glacier of the Karakoram, by high-throughput sequencing of the V5-V6 hypervariable regions of the 16S rRNA gene. We found that Betaproteobacteria dominated bacterial communities, with large abundance of genera Polaromonas, probably thanks to its highly versatile metabolism, and Limnohabitans, which may have been favoured by the presence of supraglacial lakes in the area where cryoconite holes were sampled. Variation in bacterial communities among different sampling areas of the glacier could be explained by divergent selective processes driven by variation in environmental conditions, particularly pH, which was the only environmental variable that significantly affected the structure of bacterial communities. This variability may be due to both temporal and spatial patterns of variation in environmental conditions.
冰尘穴是在冰川表面形成的小池塘，其底部含有深色碎屑（冰尘），并栖息着活跃的生态群落。北极冰川和山区冰川之间以及世界不同地区的冰川之间，细菌群落结构的差异已有记录。在本研究中，我们通过对16S rRNA基因V5-V6高变区进行高通量测序，研究了喀喇昆仑山脉一条大型（长62公里、表面积524平方公里）冰川——巴尔托洛冰川冰尘穴细菌群落的结构。我们发现β-变形菌纲在细菌群落中占主导地位，极地单胞菌属大量存在，这可能得益于其高度多样的代谢，还有栖湖菌属，在采集冰尘穴样本的区域，其存在可能因冰上湖泊而更具优势。冰川不同采样区域细菌群落的差异，可以用环境条件变化（特别是pH值，这是唯一显著影响细菌群落结构的环境变量）驱动的不同选择过程来解释。这种变异性可能是由于环境条件变化的时间和空间模式共同导致的。
