Biogeography of microbial communities in high‐latitude ecosystems: Contrasting drivers for methanogens, methanotrophs and global prokaryotes
Christophe V. W. Seppey, Léa Cabrol, Frédèric Thalasso, Laure Gandois, Céline Lavergne, Karla Martinez‐Cruz, Armando Sepulveda‐Jauregui, Polette Aguilar‐Muñoz, María Soledad Astorga‐España, Rolando Chamy, Bruna Martins Dellagnezze, Claudia Etchebehere, Gilberto J. Fochesatto, Oscar Gerardo-Nieto, Andrés Mansilla, Alison E. Murray, Maxime Sweetlove, Nikita Tananaev, Roman Teisserenc, Alexander Tøsdal Tveit, Anton Van de Putte, Mette M. Svenning, Maialen Barret
Abstract
Methane-cycling is becoming more important in high-latitude ecosystems as global warming makes permafrost organic carbon increasingly available. We explored 387 samples from three high-latitudes regions (Siberia, Alaska and Patagonia) focusing on mineral/organic soils (wetlands, peatlands, forest), lake/pond sediment and water. Physicochemical, climatic and geographic variables were integrated with 16S rDNA amplicon sequences to determine the structure of the overall microbial communities and of specific methanogenic and methanotrophic guilds. Physicochemistry (especially pH) explained the largest proportion of variation in guild composition, confirming species sorting (i.e., environmental filtering) as a key mechanism in microbial assembly. Geographic distance impacted more strongly beta diversity for (i) methanogens and methanotrophs than the overall prokaryotes and, (ii) the sediment habitat, suggesting that dispersal limitation contributed to shape the communities of methane-cycling microorganisms. Bioindicator taxa characterising different ecological niches (i.e., specific combinations of geographic, climatic and physicochemical variables) were identified, highlighting the importance of Methanoregula as generalist methanogens. Methylocystis and Methylocapsa were key methanotrophs in low pH niches while Methylobacter and Methylomonadaceae in neutral environments. This work gives insight into the present and projected distribution of methane-cycling microbes at high latitudes under climate change predictions, which is crucial for constraining their impact on greenhouse gas budgets.