MSc. Sandro Ginesi Limnological Station University of Zürich Seestrasse 187 CH-8802 Kilchberg sandroroberto.ginesi@uzh.ch phone: +41 (0)44 63 49224 fax: +41 (0)44 63 41225 Research Interests
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Research Interests

Planktothrix rubescens, a filamentous cyanobacterium, is the dominant planktonic organism in Lake Zurich. Because of its ability to produce the toxin microcystin (MC), it is harmful for many organisms, including us humans. In Lake Zurich a seasonal trend was observed, in which mutations inactivating microcystin synthesis leading to non-toxic filaments become more abundant during deep water turnover in spring. Over the last century, annual deep water turnover has also led to a selection for strong gas vesicle (GV) genotypes in P. rubescens, which they need to retain their buoyancy. While having stronger gas vesicles is better for surviving deep water turnover in spring, producing weaker gas vesicles is expected to be less costly and of advantage in summer and autumn in regard to growth rates.

Due to lake warming, only partial mixing of the lake has become more frequent over the past few years which could drastically alter the GV and MC genotype composition.

My work will focus on explaining the trends already mentioned with the importance of environmental factors and/or a possible connection between the selection for P. rubescens gas vesicle and non-toxic genotypes, allowing to evaluate potential future changes.