Project leaders: Prof. Dr. Tim Urich (University of Greifswald), Prof. Dr. Dörte Becher (University of Greifswald)

Methanogenic archaea are, together with methanotrophs (see A5) the most important determinants of the potential flux of CH4 from wetlands to the atmosphere. To date, there is no census of methanogen identity, abundance and activity in rewetted fens, and their abiotic and biotic drivers, although the latter are thought to be different from those in natural wetlands. Project A6 aims to provide such a census, by mapping the abundance and identity of methanogenic archaea in the Screening Sites. Furthermore A6 aims to assess their role for the GHG budget in rewetted fens by probing spatio-temporal compositional dynamics and activity relative to measured GHG fluxes, based on microbiomics, and process studies where feasible. We hypothesize that methylotrophic methanogens are more important for the methane balance of rewetted fens than previously assumed. Furthermore, we anticipate that antagonistic interactions with sulfur-cycling bacteria might reduce methanogen abundance and activity. A6 will investigate methanogens at all experimental levels of WETSCAPES2.0. Using cutting-edge proteomics, we will specifically look into the ecophysiology of novel, as yet poorly constrained methanogens, i.e. the methylotrophic Methanomassiliicoccales.