De Lange, H.J., E. Van Donk
Abstract:
The impact of UV-B irradiated phytoplankton on the life history parameters of Daphnia was studied. Three species of Chlorophyceae (Chlamydomonas reinhardtii, Scenedesmus acutus and Scenedesmus subspicatus) and one species of Cryptophyceae (Cryptomonas pyrenoidifera) were cultured with and without exposure to UV-B radiation and fed to D. pulex. Fatty acid composition of the phytoplankton was determined.
The daphnids feeding on UV-B irradiated algae were smaller in size, produced less and smaller offspring, and had a reduced population growth rate.
Lipid analysis of the phytoplankton showed a reduced total fatty acid content under UV-B radiation for all four species. Changes in the content of unsaturated fatty acids was species specific.
The results indicate that the energy transfer between the first and second trophic level is negatively influenced by UV-B radiation.
(Department of Water Quality Management & Aquatic Ecology, Agricultural University Wageningen, PO Box 8080, 6700 DD Wageningen, The Netherlands)
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