1. Institute of Microbiology, Russian Academy of Sciences, Prosp. 60-let Octyabrya 7, k.2, 117811 Moscow, Russia
2. Swiss Federal Institute for Environmental Science and Technology (EAWAG), Limnological Research Center, CH-6047 Kastaniebaum, Switzerland
3. Swiss Federal Institute for Environmental Science and Technology (EAWAG), Ueberlandstrasse 133, CH-8600 Duebendorf, Switzerland