Congruent changes in microbial community dynamics and ecosystem methane fluxes following natural drought in two restored fens

Both the frequency and intensity of drought events are expected to increase, with unresolved alterations peatland methane cycling involved microbial communities. While existing studies have assessed effects via experimental approaches under controlled conditions, our knowledge, no examined in-situ natural in restored temperate fens. In this study, we used quantitative polymerase chain reaction (qPCR) high throughput 16S rRNA gene amplicon sequencing DNA complementary (cDNA) determine abundances community structure total putatively active communities following 2018 European summer drought. Together geochemical flux data, compared these results a non-drought reference dataset. During drought, water level rates decreased new recent minimum both This corresponded pronounced shifts porewater geochemistry. Microbial composition year differed markedly, was characterized by greater relative abundance aerobic methanotrophs, and, one two sites, decrease methanogen abundance. contrast years, type I methanotrophs were clearly more dominant than II cDNA confirmed activity during Methylomonaceae having highest average bacterial transcripts. We show that changes dynamics, geochemistry, ecosystem fluxes can be substantial fens, provide first evidence from which suggests methanotroph populations response effects. Type may represent key control over emissions fens subject • Drought substantially. dynamics reflected conditions at sites. Methanogen Proportion low similar year. dominated profile