1. Department of Geobiology; University of Göttingen; 37077 Göttingen Germany
2. Hanse-Wissenschaftskolleg, Institute for Advanced Study; 27753 Delmenhorst Germany
3. Univ Rennes, CNRS, Géosciences Rennes - UMR 6118; 35000 Rennes France
4. Finnish Museum of Natural History, University of Helsinki; 00014 Helsinki Finland
5. Faculty of Biological and Environmental Sciences; University of Helsinki; 00014 Helsinki Finland