1. Institute of Groundwater Ecology, Helmholtz Zentrum Munchen Ingolstadter Landstraße 1, 85764 Neuherberg Bavaria Germany
2. Center for Microbial Ecology and Technology (CMET), Ghent University Coupure Links 653, Ghent 9000 Belgium
3. Division of Limnology University of Vienna, Department of Functional and Evolutionary Ecology Althanstrasse 14 Vienna 1090 Austria
4. Chair of Analytical Chemistry and Water Chemistry Technical University of Munich Marchioninistrasse 17, D‐81377 Munich Germany