1. Shirshov Institute of Oceanology, Russian Academy of Science, Nakhimovsky Prosp. 36, Moscow 117218, Russia
2. Ecological Complexity and Modeling Laboratory, Department of Botany and Plant Sciences, University of California, Riverside, CA 92521-0124, USA
3. Institute of Environmental Systems Research, Department of Mathematics, Osnabrück University, Osnabrück D-49069, Germany