1. The Man-Society-Environment Program, Department of Environmental Sciences, University of Basel, Vesalgasse 1, 4051 Basel, Switzerland
2. Department of Microbial Ecology, Biologische Anstalt Helgoland, Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung, Kurpromenade, 27498 Helgoland, Germany
3. Organic Geochemistry Group, MARUM─Center for Marine Environmental Sciences and Faculty of Geosciences, University of Bremen, Leobener Str. 8, 28359 Bremen, Germany