1. Department of Agroecology and Environment, Agroscope, 8046 Zurich, Switzerland
2. Department of Plant and Microbial Biology, University of Zurich, 8008 Zurich, Switzerland
3. Department of Microbiological Sciences, North Dakota State University, Fargo, North Dakota 58108-6050, United States
4. Department of Environmental Chemistry, Eawag, 8600 Dübendorf, Switzerland
5. Department of Chemistry, University of Zurich, 8057 Zurich, Switzerland
6. Department of Methods Development and Analytics, Agroscope, 8046 Zurich, Switzerland