1. Microbial Systems Ecology Group, Department of Environmental Systems Sciences, Institute of Biogeochemistry and Pollutant Dynamics, ETH-Zurich, Zurich 8006, Switzerland
2. Department of Environmental Microbiology, Eawag: Swiss Federal Institute of Aquatic Sciences, Duebendorf 8600, Switzerland
3. Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139
4. Department of Civil, Environmental and Geomatic Engineering, Institute of Environmental Engineering, ETH Zurich, Zurich 8093, Switzerland
5. Department of Marine Sciences, University of Georgia, Athens, GA 30602
6. Environmental Engineering Institute, School of Architecture, Civil and Environmental Engineering, École polytechnique fédérale de Lausanne, CH-1015 Lausanne, Switzerland