Aquatic Sciences Meeting, Albuquerque 2001

CS37 Zooplankton

Date: Tuesday, February 13, 2001, Time: 10:45:00 AM

Location: Aztec

Straile, D, , Limnological Institute, University of Konstanz, Konstanz, Germany, Dietmar.Straile@uni-konstanz.de

Hoegg, R, , Limnological Institute, University of Konstanz, Konstanz, Germany,

Einsle, U, , Institut fuer Seenforschung, Langenargen, Germany,

SPECIFIC COPEPOD LIFE HISTORY DETERMINES LONG-TERM POPULATION DYNAMICS DURING EUTROPHICATION AND RE-OLIGOTROPHICATION

Population dynamics of four copepod species (Eudiaptomus gracilis, Mesocyclops leuckartii, Cyclops abyssorum, and Cyclops vicinus) was investigated in Lake Constance from 1970 to 1993, i.e., during a period with increasing and since 1980 decreasing phosphorus concentrations. The life history of the four copepod species differed in respect to the timing of reproduction, and the occurrence as well as seasonal and ontogenetic timing of diapause. The copepod species' seasonal timing of reproduction seemed to be the cue to the understanding of their long-term dynamics. The abundance of Mesocyclops leuckartii,which reproduced during summer increased with decreasing nutrient loadings. Likewise, the summer cohorts of Eudiaptomus and Cyclops abyssorum were increasing. In contrast, late winter/spring cohorts of these two species declined with decreasing nutrient loadings. For both species, the timing of maximum seasonal abundance has shifted from spring towards summer during the re-oligotrophication of the lake.

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Aquatic Sciences Meeting, Albuquerque 2001

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