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Projekt
Influence of the year-to-year variation of water temperature on the coupling between benthic and pelagic food webs
Antragsteller
Dr. Stephan Hülsmann
Fachliche Zuordnung
Hydrogeologie, Hydrologie, Limnologie, Siedlungswasserwirtschaft, Wasserchemie, Integrierte Wasserressourcen-Bewirtschaftung
Förderung
Förderung von 2004 bis 2011
Projektkennung
Deutsche Forschungsgemeinschaft (DFG) - Projektnummer 5429846
Recent climate records reveal a warming during winter and spring in Middle Europe rather than an increase in mean annual temperatures. While the direct influence of temperature on plankton phenology is already well documented, insect larvae living temporarily or even permanently in the upper sediment horizon of lakes were so far not included into these investigations. Coupling of these benthic organisms with the pelagic food web was neglected in this context. From long-term investigations in Bautzen Reservoir (1991-1998) we derive a hypothesis which postulates a strong coupling of pelagic and benthic food webs such that changes in timing and duration of the pupation period of benthic prey species (chironomids and Chaoborus) affect indirectly the population dynamics of a planktonic species (Daphnia). This indirect effect is mediated by two temperature-controlled alternative cascades of direct effects via consumptive interactions by perch. We propose to test this hypothesis by a combination of field observations in Saidenbach Reservoir (which could serve as study site for a "cluster" of other proposals), laboratory and modelling studies. The results would have significant implications for predicting the effects of global warming of the coupling between benthic and pelagic food webs and on the water quality of reservoirs.
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