1. University of Greifswald,, Institute of Microbiology, Felix-Hausdorff-Str. 8, 17487 Greifswald , Germany
2. Greifswald Mire Center , Soldmannstraße 15, 17487 Greifswald , Germany
3. Aarhus University,, Department of Bioscience , F. Møllers Allé 3, 8000 Aarhus C , Denmark
4. Leibniz-Institute of Freshwater Ecology and Inland Fisheries,, Department of Ecohydrology and Biogeochemistry , Müggelseedamm 301, 12587 Berlin , Germany