Species interactions and distinct microbial communities in high Arctic permafrost affected cryosols are associated with the CH₄ and CO₂ gas fluxes

• Published in: Environmental Microbiology
• Main Authors: Altshuler, Ianina, Hamel, Jérémie, Turney, Shaun, Magnuson, Elisse, Lévesque, Roger, Greer, Charles W., Whyte, Lyle G.
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2019
• Subjects: Arctic; Ice; permafrost; wedge*
• Online Access: https://doi.org/10.1111/1462-2920.14715; https://nrc-publications.canada.ca/eng/view/object/?id=50841b1d-f036-4acf-86de-03662ba631d7; https://nrc-publications.canada.ca/fra/voir/objet/?id=50841b1d-f036-4acf-86de-03662ba631d7

Microbial metabolism of the thawing organic carbon stores in permafrost results in a positive feedback loop of greenhouse gas emissions. CO₂ and CH₄ fluxes and the associated microbial communities in Arctic cryosols are important in predicting future warming potential of the Arctic. We demonstrate that topography had an impact on CH₄ and CO₂ flux at a high Arctic ice-wedge polygon terrain site, with higher CO₂ emissions and lower CH₄ uptake at troughs compared to polygon interior soils. The pmoA sequencing suggested that USCα cluster of uncultured methanotrophs is likely responsible for observed methane sink. Community profiling revealed distinct assemblages across the terrain at different depths. Deeper soils contained higher abundances of Verrucomicrobia and Gemmatimonadetes, whereas the polygon interior had higher Acidobacteria and lower Betaproteobacteria and Deltaproteobacteria abundances. Genome sequencing of isolates from the terrain revealed presence of carbon cycling genes including ones involved in serine and ribulose monophosphate pathways. A novel hybrid network analysis identified key members that had positive and negative impacts on other species. Operational Taxonomic Units (OTUs) with numerous positive interactions corresponded to Proteobacteria, Candidatus Rokubacteria and Actinobacteria phyla, while Verrucomicrobia and Acidobacteria members had negative impacts on other species. Results indicate that topography and microbial interactions impact community composition. Peer reviewed: Yes NRC publication: Yes