- CoDL Fennoscandian Shield
The microbial communities of the Fennoscandian shield have been characterized by both cultur-dependent and independent methods since the 1980s. These approaches have revealed a diversity of microorganisms of wide metabolic variety. Only a small part of the microbial communities appear to be truly autotrophic. Methane is an important carbon source in these deep groundwaters and is very abundant. Methane composes the clear majority of the gasses in these groundwater samples. It has still not been shown, however, that any specific group of microorganisms would utilize this methane in the Finnish deep terrestrial groundwater. Typical methane oxidizing bacterial or archaeal linages have not yet been detected. Nevertheless, an enrichment of sulphides at methane-sulphate transition zones where other carbon sources than methane are scarce, suggest that methane is oxidized in combination with sulphate reduction. The number of methanogens and sulphate reducers is low. Our objective is to study the community composition of archaea and bacteria at different depth of Olkiluoto groundwater. We want to clarify the co-existence of specific microbial groups in relation to hydrogeochemistry and the presence of methane and sulphides.