1. Department of Earth and Environmental Sciences; Ludwig-Maximilians-Universität München; Munich 80333 Germany
2. Central Facility for Electron Microscopy; University of Ulm; Ulm 89081 Germany
3. Institute of Materials Research; German Aerospace Center (DLR); Cologne 51147 Germany
4. Institute of Virology; University Medical Center Ulm; Ulm 89081 Germany
5. GEOMAR Helmholtz Centre for Ocean Research Kiel; Marine Ecology - Evolutionary Ecology; Kiel 24105 Germany