Anaerobic oxidation of methane and associated microbiome in anoxic water of Northwestern Siberian lakes
Anaerobic oxidation of methane and associated microbiome in anoxic water of Northwestern Siberian lakes
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DOI：
10.1016/j.scitotenv.2020.139588
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发表时间：
2020-09-20
影响因子：
9.8
通讯作者：
Barret, Maialen
中科院分区：
文献类型：
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作者：
Cabrol, Lea;Thalasso, Frederic;Barret, Maialen
北极湖泊向大气排放甲烷(CH4)。这一通量的大小可以随着永久冻土的融化而增加，但也可能被微生物的CH4氧化所缓解。甲烷在含氧水中的氧化已经得到了广泛的研究，但甲烷厌氧氧化(AOM)对甲烷缓解的贡献还不完全清楚。我们在俄罗斯伊加尔卡附近一个不连续的永久冻土区调查了四个北西伯利亚层状湖泊。对水体中甲烷浓度的分析表明，在四个湖泊的缺氧层中，向上扩散的甲烷有60%到100%被氧化。PmoA和MCRA基因qPCR和16S rRNA基因metabarcoding的组合表明，同一类群可能是四个湖泊缺氧水体中的主要甲烷氧化细菌(MOB)，它们都属于甲基单胞菌科，包括优势属甲氧杆菌和文氏菌。甲基单胞菌属、地霉属和地杆菌属中甲基单胞菌与OTUS的相关性表明，AOM可能发生在MOB、反硝化菌和铁循环伙伴之间的相互作用中。我们得出结论，甲基单胞菌科内的MOB可能通过在CH4离开缺氧区之前减少产生的大部分CH4，对这些西伯利亚北极湖泊中的CH4循环产生至关重要的影响。这一发现强调了甲基单胞菌科AOM的重要性，并扩大了我们对湖泊中CH4循环的认识，CH4循环是全球CH4循环的重要组成部分。
Arctic lakes emit methane (CH4) to the atmosphere. The magnitude of this flux could increase with permafrost thaw but might also be mitigated by microbial CH4 oxidation. Methane oxidation in oxic water has been extensively studied, while the contribution of anaerobic oxidation of methane (AOM) to CH4 mitigation is not fully understood. We have investigated four Northern Siberian stratified lakes in an area of discontinuous permafrost nearby Igarka, Russia. Analyses of CH4 concentrations in the water column demonstrated that 60 to 100% of upward diffusing CH4 was oxidized in the anoxic layers of the four lakes. A combination of pmoA and mcrA gene qPCR and 16S rRNA gene metabarcoding showed that the same taxa, all within Methylomonadaceae and including the predominant genus Methylobacter as well as Crenothrix, could be the major methane-oxidizing bacteria (MOB) in the anoxic water of the four lakes. Correlation between Methylomonadaceae and OTUs within Methylotenera, Geothrix and Geobacter genera indicated that AOM might occur in an interaction between MOB, denitrifiers and iron-cycling partners. We conclude that MOB within Methylomonadaceae could have a crucial impact on CH4 cycling in these Siberian Arctic lakes by mitigating the majority of produced CH4 before it leaves the anoxic zone. This finding emphasizes the importance of AOM by Methylomonadaceae and extends our knowledge about CH4 cycle in lakes, a crucial component of the global CH4 cycle.