Gutiérrez Marcelo H, Galand Pierre E, Moffat Carlos, Pantoja Silvio
Department of Oceanography, Universidad de Concepción, Concepción, Chile.
COPAS Sur-Austral Program, Universidad de Concepción, Concepción, Chile.
Environ Microbiol. 2015 Oct;17(10):3882-97. doi: 10.1111/1462-2920.12872. Epub 2015 May 8.
Jorge Montt glacier, located in the Patagonian Ice Fields, has undergone an unprecedented retreat during the past century. To study the impact of the meltwater discharge on the microbial community of the downstream fjord, we targeted Bacteria, Archaea and Fungi communities during austral autumn and winter. Our results showed a singular microbial community present in cold and low salinity surface waters during autumn, when a thicker meltwater layer was observed. Meltwater bacterial sequences were related to Cyanobacteria, Proteobacteria, Actinobacteria and Bacteriodetes previously identified in freshwater and cold ecosystems, suggesting the occurrence of microorganisms adapted to live in the extreme conditions of meltwater. For Fungi, representative sequences related to terrestrial and airborne fungal taxa indicated transport of allochthonous Fungi by the meltwater discharge. In contrast, bottom fjord waters from autumn and winter showed representative Operational Taxonomic Units (OTUs) related to sequences of marine microorganisms, which is consistent with current models of fjord circulation. We conclude that meltwater can significantly modify the structure of microbial communities and support the development of a major fraction of microorganisms in surface waters of Patagonian fjords.
豪尔赫·蒙特冰川位于巴塔哥尼亚冰原，在过去一个世纪里经历了前所未有的退缩。为了研究融水排放对下游峡湾微生物群落的影响，我们在南半球的秋季和冬季对细菌、古菌和真菌群落进行了研究。我们的结果显示，在秋季，当观察到较厚的融水层时，寒冷且低盐度的表层水中存在独特的微生物群落。融水细菌序列与先前在淡水和寒冷生态系统中鉴定出的蓝细菌、变形菌、放线菌和拟杆菌有关，这表明存在适应在融水极端条件下生存的微生物。对于真菌，与陆地和空气传播真菌类群相关的代表性序列表明，融水排放会输送外来真菌。相比之下，秋冬季节峡湾底部的水显示出与海洋微生物序列相关的代表性操作分类单元（OTU），这与当前的峡湾环流模型一致。我们得出结论，融水可显著改变微生物群落结构，并支持巴塔哥尼亚峡湾表层水中大部分微生物的生长。
