Arctic Permafrost Microbiomes: A Meta-Analysis
Abstract
Arctic soils will be a net source of greenhouse gas (GHG) emissions (CO2, CH4, and N2O) as temperatures rise according to warming experiments and field observations. Indeed, permafrost is already melting, as evidenced by increasing active layer thickness, and increased rates of permafrost loss in the past decade.
Microbes contribute substantially to permafrost GHG emission. Recent studies suggest that permafrost types and features vary greatly across the Arctic, and topography and local hydrological conditions, specifically, appear to be important determinants of microbiomes and GHG emissions. However, knowledge of their geospatial variation or connectivity across the Arctic is limited. Similarly, microbiomes across permafrost soils appear to have some common features, including dominance by Actinobacteria and a shift from DNA repair and survival strategy genes to carbon mineralization genes as permafrost thaws, but landscape-level differences have yet to be analyzed. To predict future GHG emissions, we must quantify the effects of permafrost soil properties on microbiomes across the Arctic. This meta-analysis of permafrost metagenomes across the Arctic quantifies soil characteristics and microbial community composition and metabolic potential. We obtained metagenomes from Alaska, Sweden, Canada, Russia, and Antarctica (MacKelprang et al 2011 Nat; Hultman et al 2015 Nat; Chauhan et al 2014 Gen Announc; Emerson et al 2018 Nat Microbiol; Rivkina et al 2016 Biogeosci; Goordial et al 2017 Environ Microbiol) to compare environmental drivers including but not limited to water content, topography, continuity, active layer depth, and vegetation. The microbial communities inhabiting these soils have some common members and metabolic capacity, including the prominence of Actinobacteria and stress response genes, but differ in the extent to which Eukaryotic and viral populations were represented and in the abundance and biochemistry of methanogens. These results contribute to an understanding of global variation in the microbial ecology of permafrost. Recognizing geospatial patterns in soil properties and microbiome characteristics across Arctic permafrost landscapes will allow us to better predict how permafrost responds to global climate change.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.B31E2502D
- Keywords:
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- 0428 Carbon cycling;
- BIOGEOSCIENCESDE: 0475 Permafrost;
- cryosphere;
- and high-latitude processes;
- BIOGEOSCIENCESDE: 0702 Permafrost;
- CRYOSPHEREDE: 1615 Biogeochemical cycles;
- processes;
- and modeling;
- GLOBAL CHANGE