1. Center for Applied Geoscience, Geomicrobiology, University of Tuebingen, Sigwartstrasse 10, 72076 Tuebingen, Germany
2. Department of Isotope Biogeochemistry, ProVIS − Centre for Chemical Microscopy, Helmholtz Centre for Environmental Research GmbH − UFZ, Permoserstrasse 15, 04318 Leipzig, Germany