1. Department of Limnology and Oceanography; University of Vienna; Vienna Austria
2. Institute of Microbiology; University of Greifswald; Greifswald Germany
3. Department of Biological Sciences; University of Alabama; Tuscaloosa Alabama USA
4. Stream Biofilm and Ecosystem Research Laboratory, School of Architecture, Civil and Environmental Engineering; Ecole Polytechnique Fédérale Lausanne; Lausanne Switzerland