Community dynamics of methanogenic archaea in a rapidly changing peatland ecosystem in the zone of discontinuous permafrost in North-Norway

Northern palsa peatlands and permafrost landscapes are already subjected to distinct geomorphological and biogeochemical changes due to the atmospheric warming as it is predicted to occur faster and stronger especially in the northern latitudes. It is als o known that these environments harbor a huge amount of carbon. This enormous storage is thought to have a considerable influence on the release of methane (CH4). Methane is produced by methanogenic archaea as the terminal step in the decomposition of org anic matter. CH4 is also known as a very potent greenhouse gas. Recent methane measurements in summer 2010 in the Bøttemyra palsa peatland in Finnmark (Northern Norway) indicated already a high methanogenic activity. Palsa systems are therefore ideal in s itu models for investigating the effects of permafrost degradation. So far, there is no information about the microbial communities in these systems. Culture-independent techniques became the method of choice to study methanogenic communities from environ mental samples. Only a few studies have used qPCR for the quantification of methanogenic archaea using the mcrA gene. As the mcrA gene is a conserved functional gene, it is also ideal to link phylogeny with activity. So far, no transcriptomic study based on the mcrA messenger RNA has been conducted for both qualitative as well as quantitative investigations to determine the active part of the methanogenic community in subarctic terrestrial environments. The objective of the proposed work is to combine est ablished soil geochemical and state-of-the-art molecular methods as well as statistical tools to describe the spatial highly heterogenic palsa ecosystem regarding the methanogenic communities. Therefore, different stages of soil succession and degradation in a subarctic peatland will be investigated to determine the community structure and abundance of active methanogenic archaea using next generation 454 pyrosequencing and qPCR.