1. Department of Limnology and Oceanography; Center of Functional Ecology University of Vienna, Althanstrasse 14; 1090 Vienna Austria
2. National Institute for Aquatic Resources, Section for Oceans and Arctic; Technical University of Denmark, Kavalergaarden 6; 2920 Charlottenlund Denmark
3. Department of Subsurface Geobiological Analysis and Research; Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Natushima 2-15; Yokosuka Kanagawa 237-0061 Japan
4. Department of Marine Microbiology and Biogeochemistry; Royal Netherlands Institute for Sea Research Utrecht University, PO Box 59; AB Den Burg 1790 The Netherlands