1. Department of Environmental Systems Science, Institute for Atmospheric and Climate Sciences, Eidgenössiche Technische Hochschule (ETH) Zurich, 8002 Zurich, Switzerland
2. Department of Environmental Systems Science, Institute of Biogeochemistry and Pollutant Dynamics, Eidgenössiche Technische Hochschule (ETH) Zurich, 8002 Zurich, Switzerland
3. Department of Environmental Microbiology, 8600 Dubendorf, Eawag, Switzerland
4. NORCE Norwegian Research Centre, 5838 Bergen, Norway
5. Nansen Environmental and Remote Sensing Center, 5007 Bergen, Norway