Institute of Bioengineering, Research Center of Biotechnology of the Russian Academy of Sciences, Moscow, Russia, 119071.
Winogradsky Institute of Microbiology, Research Center of Biotechnology of the Russian Academy of Sciences, Moscow, Russia, 119071.
Antonie Van Leeuwenhoek. 2019 Dec;112(12):1801-1814. doi: 10.1007/s10482-019-01308-1. Epub 2019 Aug 1.
Although arctic and subarctic lakes are important sources of methane, the emission of which will increase due to the melting of permafrost, the processes related to the methane cycle in such environments are far from being comprehensively understood. Here we studied the microbial communities in the near-bottom water layer and sediments of the meromictic subarctic Lake Svetloe using high-throughput sequencing of the 16S rRNA and methyl coenzyme M reductase subunit A genes. Hydrogenotrophic methanogens of the order Methanomicrobiales were abundant, both in the water column and in sediments, while the share of acetoclastic Methanosaetaceae decreased with the depth of sediments. Members of the Methanomassiliicoccales order were absent in the water but abundant in the deep sediments. Archaea known to perform anaerobic oxidation of methane were not found. The bacterial component of the microbial community in the bottom water layer included oxygenic (Cyanobacteria) and anoxygenic (Chlorobi) phototrophs, aerobic Type I methanotrophs, methylotrophs, syntrophs, and various organotrophs. In deeper sediments the diversity of the microbial community decreased, and it became dominated by methanogenic archaea and the members of the Bathyarchaeota, Chloroflexi and Deltaproteobacteria. This study shows that the sediments of a subarctic meromictic lake contain a taxonomically and metabolically diverse community potentially capable of complete mineralization of organic matter.
尽管北极和亚北极湖泊是甲烷的重要来源，由于永久冻土的融化，甲烷的排放将会增加，但这些环境中与甲烷循环相关的过程远未被全面理解。在这里，我们使用 16S rRNA 和甲基辅酶 M 还原酶亚基 A 基因的高通量测序研究了亚北极分层湖 Svetloe 的近底层水和沉积物中的微生物群落。产氢甲烷菌目（Methanomicrobiales）在水柱和沉积物中都很丰富，而乙酸营养型 Methanosaetaceae 的比例随着沉积物深度的增加而减少。在水层中不存在 Methanomassiliicoccales 目成员，但在深层沉积物中却很丰富。没有发现已知能进行甲烷厌氧氧化的古菌。底层水层微生物群落的细菌组成包括需氧（蓝细菌）和微氧（绿弯菌）光合生物、好氧 I 型甲烷氧化菌、甲基营养菌、共生菌和各种有机营养菌。在更深的沉积物中，微生物群落的多样性减少，由产甲烷古菌和 Bathyarchaeota、Chloroflexi 和 Deltaproteobacteria 的成员主导。本研究表明，亚北极分层湖的沉积物中含有一个在分类学和代谢上多样化的群落，可能能够完全矿化有机物。
