1. Swiss Federal Institute of Technology (ETH) and Swiss Federal Institute for Environmental Science and Technology (EAWAG), CH-8600 Dübendorf, Switzerland, Design and Technology Institute for Geophysical and Ecological Engineering, Siberian Division of the Russian Academy of Sciences, Novosibirsk 630090, Russia, and Limnological Institute of the Siberian Division of the Russian Academy of Sciences, Irkutsk 664033, Russia