Die interaktiven Folgen globaler Erwärmung und zunehmender UV-Strahlung für arktische Planktongemeinschaften am Beispiel von Daphnia (Wasserflöhen)
Final Report Abstract
The interactive consequences of global warming and increasing UV-radiation on sub-Arctic plankton communities in comparison to temperate populations were investigated in Daphnia (water flea) with emphasis on the role of lipids. The aim was to distinguish between the effects UVR and temperature have directly on sterol and FA-composition of temperate compared to sub-Arctic Daphnia, and the indirect effects of these same two Stressors on FA composition and sterols in the plankton food web dynamics. In order to The experiments estimate the actual relevance of the results obtained in the standardized laboratory experiments were exposed local Daphnia populations in sub-Arctic Finland to UVR at two temperatures following the same parameters as in the laboratory experiments. Indirect effects of UVR via UV-treated algae supplied to Daphnia pulex at increasing temperatures under sublethal UVR-exposure were studied under controlled conditions. Supplementation of food algae with individual FAs tested whether certain FAs affect UV-tolerance at increasing temperatures indirectly via the food chain. In the lab experiments we found significant morphological differences between D. pulex orignating from temperate and sub-Arctic habitats at increasing temperatures and sublethal UVR-exposure. They were reflected in the sterol levels of the daphnids under the various stresses. The most sensitive parameters were the size of the mid-gut section of the intestine and the sterol quantities/animal. Indirect effects via UV-treated food algae altered the responses to multiple stress in both Daphnia populations but were not related to the sterol levels of the daphnids. Supplementation of the food algae with 4 PUFAs did not improve the UV-tolerance of the temperate daphnids with severe negative effects on the reproductive output. In the field experiments both sub-Arctic Daphnia species showed increased morphological damage at increased temperatures and UVR-exposure. Changes in sterol quantities related to these changes. The fatty acid composition and quantities were not affected by temperature or UVR-exposure, except for ALA and EPA, which appeared to be UVR-sensitive.
Publications
- (2006): Food chain effects of sublethal ultraviolet radiation on sub-Arctic Daphnia pulex-a field and laboratory study. Archive Hydrobiologie 167 (1-4): 501-513
Zellmer I.D., Arts M.T., Sustr. V.
- Ozonloch und globale Erwärmung - Gibt es Auswirkungen auf das Plankton subarktischer Teiche? Ergebnisse aus dem Freiland und dem Labor. DGL Tagung Dresden September 2006
Zellmer, I.D.
- (2007): Consequences of increasing temperature and UVR on sub-Arctic plankton communities. Proceedings of the Gesellschaft für Ökologie vol 37:383
Zellmer I.D.
- The Effects of UV Radiation on Primary Producers and their Consumers; a Comparison between Lab and Field Studies. Arctic Frontiers conference, Tromso, Norway, January (2007)
Arts M.T., Zellmer I.D., Browman H.L, Jokinen I.
- UV-tolerance of Daphnia be altered by food quality? The role of carotenoids and lipids. 30th SIL conferenz in Montreal, Canada (2007)
Zellmer I.D., Arts M.T., von Elert E.
