1. Department of Isotope Biogeochemistry, UFZ - Helmholtz Centre for Environmental Research, Permoserstraße 15, 04318 Leipzig, Germany, Isodetect - Company for Isotope Monitoring, Ingolstädter Landstraße 1, 85764 Neuherberg/Oberschleißheim, Germany, Department of Environmental Microbiology, UFZ - Helmholtz Centre for Environmental Research, Permoserstraße 15, 04318 Leipzig, Germany, Laboratory of Microbiology, Wageningen University, de Dreijen 10, 6703 HB Wageningen, The Netherlands, and Interdisciplinary...