1. Institute of Ecology, University of Innsbruck, Technikerstr. 25, 6020 Innsbruck, Austria.
2. Department of Cell Biology, University of Salzburg, Hellbrunnerstr. 34, 5020 Salzburg, Austria.
3. Research Institute for Limnology, Mondsee, University of Innsbruck, Mondseestr. 9, 5310 Mondsee, Austria.
4. Department of Botany, Faculty of Biology, Sofia University, “St. Kliment Ohridski”, Bldg. Dr. Zankov 8, 1164 Sofia, Bulgaria.
5. School of Oceanography, University of Washington, Box 355351, Seattle, Washington 98195.