Jack McFarland Kristen L. Manies Mary-Cathrine Leewis Steve Blazewicz Miriam C. Jones Rebecca Neumann Jason Keller Rachel Cohen Eugenie S. Euskirchen Colin W. Edgar Merritt R. Turetsky William Cable Mark Waldrop 2021 <div class="article-section__content en main"><p>Permafrost thaw in northern ecosystems may cause large quantities of carbon (C) to move from soil to atmospheric pools. Because soil microbial communities play a critical role in regulating C fluxes from soils, we examined microbial activity and greenhouse gas production soon after permafrost thaw and ground collapse (into collapse-scar bogs), relative to the permafrost plateau or older thaw features. Using multiple field and laboratory-based assays at a field site in interior Alaska, we show that the youngest collapse-scar bog had the highest CH₄<span>&nbsp;</span>production potential from soil incubations, and, based upon temporal changes in porewater concentrations and<span>&nbsp;</span>¹³C-CH₄<span>&nbsp;</span>and<span>&nbsp;</span>¹³C-CO₂, had greater summer in situ rates of respiration, methanogenesis, and surface CH₄<span>&nbsp;</span>oxidation. These patterns could be explained by greater C and N availability in the young bog, while alternative terminal electron accepting processes did not play a significant role. Field diffusive CH₄<span>&nbsp;</span>fluxes from the young bog were 4.1 times greater in the shoulder season and 1.7–7.2 times greater in winter relative to older bogs, but not during summer. Greater relative CH₄<span>&nbsp;</span>flux rates in the shoulder season and winter could be due to reduced CH₄<span>&nbsp;</span>oxidation relative to summer, magnifying the importance of differences in production. Both the permafrost plateau and collapse-scar bogs were sources of C to the atmosphere due in large part to winter C fluxes. In collapse scar bogs, winter is a critical period when differences in thermokarst age translates to differences in surface fluxes.</p></div> application/pdf 10.1029/2020JG005869 en American Geophysical Union Carbon fluxes and microbial activities from boreal peatlands experiencing permafrost thaw article