The response of Daphnia to changes in trophic status and weather patterns : a case study from Lake Constance

• Published in: ICES Journal of Marine Science
• Main Authors: Straile, Dietmar, Geller, Walter
• Format: Article in Journal/Newspaper
• Language: English
• Published: 1998
• Subjects: climate variability; Daphnia; eutrophication; Lake Constance; North Atlantic Oscillation; population dynamics; ddc:570; North Atlantic; North Atlantic oscillation
• Online Access: http://nbn-resolving.de/urn:nbn:de:bsz:352-opus-39939; https://doi.org/10.1006/jmsc.1998.0397

Relationships between changes in trophic status and weather patterns and biomass of Daphnia in Lake Constance were analysed by comparing three long term records conducted at approximately 30-year intervals. These describe the zooplankton of Lake Constance in its oligotrophic (1920-1924), mesotrophic (1952-1962), and finally meso/eutrophic (1979-1995) state. Biomass increased approximately 30-fold from the 1920s to the 1950/60s and 6-fold from the 1950/60s to the I980/90s. The former increase was evident throughout the season, the latter was restricted to the second half of the year. Daphnid biomass has not yet shown any response to the re-oligotrophication process of Lake Constance during the 1980/90s. Within the period 1979-1995, biomass in May was significantly correlated with the North Atlantic Oscillation, whereas the annual average showed no response. The magnitude of inter-annual variation in spring biomass due to climate variability was as large as the long-term response to eutrophication. Because of the key role of daphnids in freshwater ecosystems, even a temporally restricted response to climate forcing might have important consequences for the ecosystem. published published