1. Austrian Institute of Technology, Department of Bioresources/Microbiology, Seibersdorf, Austria
2. Max Planck Institute for Terrestial Microbiology, Marburg, Germany
3. Department of Biology, Faculty of Science, University of Tromsø, Tromsø, Norway
4. Netherlands Institute of Ecology, Department of Microbial Ecology, Niewersluis, Netherlands
5. University of Eastern Finland, Department of Environmental Science, Kuopio, Finland