The role of Archaea in soil carbon and nitrogen turnover
Despite the fact that Archaea was recognized as a separate kingdom some 30 years ago, virtually nothing is known about their activities in most ecosystems. Recently, a few high profile publications have acknowledged their importance in carbon (C) and nitrogen (N) turnover in marine environments, and their dominant role in ammonium oxidation in terrestrial environments. C and N turnover are some of the most extensively studied processes in forest soils. Knowledge about the factors determining the rate of these processes has implications for our understanding of plant productivity, carbon sequestration, nitrogen leakage, greenhouse gas production, etc. Still, the involvement of Archaea in these processes in terrestrial environments is to a large extent unknown. The apparent lack of attention might partly be explained by methodological constrains. This project aim at relieving these constrains and giving a first insight into the life and activities of archaea in soil environments.
The interaction between and relative importance of Archaea and bacteria for soil C and N turnover will also be determined. This will be achieved by exploiting the unique physiology of the archaeal cell-membrane to measure 13/14C incorporation into specific biomarkers. These techniques in combination with quantification of abundance and expression of relevant functional genes provide an excellent but largely unexplored opportunity to study the virtually unknown activities of this group of microorganisms.