Temperature increase affects acetate-derived methane production in Alaskan lake sediments and wetland soils

Abstract Under climate change framework, methanogens activity is expected to be strongly affected, eventually resulting in positive feedback on global climate, with higher greenhouse gas (GHG) emissions in the Arctic. This work aimed to evaluate the effect of increasing temperature on methane production rate and archaeal community of lake sediments and wetland soils from Denali to Toolik regions in Alaska (USA). For that, anaerobic acetate-amended microcosms were incubated at 5, 10, 15 and 20 °C. The acetate-derived methanogenic rate was determined and the methanogenic communities were analyzed by qPCR and 16S rRNA sequencing. Warmer temperatures yielded 4-6 times higher methane production rates and organic matter content (OM) showed significant positive correlation to methane production. Different patterns were observed in the archaeal communities after incubation at higher temperatures, with an increase in Methanosarcina abundance for most of the samples and Methanosaeta in one of the lakes tested, showing the adaptation of key acetoclastic groups among different temperatures. Our results demonstrate the impact of increasing temperature on methane production, bringing insights on key drivers involved in the process of acetoclastic methanogenic potential occurring in these ecosystems in Alaska.