Temperature Dependent Microbial Community Dynamics Modulates Methane Cycle in Permafrost-affected Soils

Abstract

Temperature Dependent Microbial Community Dynamics Modulates Methane Cycle in Permafrost-affected Soils.

Thawing permafrost promotes microbial degradation of carbon sink leading to the biogenic production of greenhouse gases such as carbon dioxide and methane. This study aims to understand how methane cycle is modulated by microbial community changes driven by different temperatures and incubation times under anaerobic condition in permafrost-affect soils. Alaska Council soil cores were incubated at 5℃, 15℃ and 25℃ with 13C-labelled substrates for 11 months under anaerobic condition. Soil DNA was extracted and then 16S rRNA gene targeting bacteria and archaea was sequenced. There are distinct patterns in bacterial and archaeal community composition between active layer and permafrost. In permafrost three methanogenic genera responded distinctively to different temperature and incubation time settings. There is a clear shift in major methanogen lineage from low to higher temperatures. ‘Ca Methanoflorens’ was replaced by Methanosarcina at 15℃ and 25℃, suggesting the modulation in methane production at different temperatures occurs by turnover among major methanogen lineages differing in their temperature specificity. These results help to understand the effect of different temperatures and incubation times on metabolic interactions between anaerobic microbes in a moist acidic Arctic tundra. [This research was supported by a National Research Foundation of Korea Grant from the Korean Government (NRF-2016M1A5A1901769).]