Aquatic Sciences Meeting, Albuquerque 2001

CS37 Zooplankton

Date: Tuesday, February 13, 2001, Time: 11:30:00 AM

Location: Aztec

Kilham, S, S, School of Environmental Science, Engineering and Policy, Drexel University, Philadelphia, PA 19104, USA, kilhams@drexel.edu

Kreeger, D, A, Patrick Center for Environmental Research, Academy of Natural Sciences, Philadelphia, PA 19103, USA, kreeger@acnatsci.org

Lanka, S, G, Patrick Center for Environmental Research, Academy of Natural Sciences, Philadelphia, PA 19103, USA, none

FEEDING RATES AND REPRODUCTIVE FITNESS OF THE CLADOCERAN DAPHNIA PULICARIA FED DIETARY SUPPLEMENTS OF PHOSPHOROUS MICROCAPSULES.

Natural seston in lakes varies enormously in quality, but new tools are needed to permit study of how multiple aspects of food quality impact zooplankton in situ. We tested whether artificial microparticulate diets could be used to manipulate food quality. We compared feeding rates and reproduction by Daphnia pulicaria when fed rations of the following diets: the alga Ankistrodesmus falcatus cultured in normal media (normal algae); A. falcatus cultured in low-P media (low-P algae); low-P algae supplemented with carbohydrate microcapsules (CHO-capsules); and low-P algae supplemented with P-laden CHO-capsules (P-capsules). D. pulicaria were fed these diets for 3 weeks. Clearance rates were measured over 24 h in week 3. Replacing a portion of the algal diet with capsules enhanced whole-diet feeding. As expected, low-P algae were an inferior diet, providing no reproduction, whereas fecundity in normal algae was 14.0 offspring per individual. Replacing a portion of the low-P algal diet with the same mass of capsules improved reproduction. Mean fecundity for animals fed CHO capsules was 5.5 and for P capsules was 13.9 offspring. Microcapsules clearly represent a valuable new tool for nutritional studies of zooplankton, demonstrating unequivocally that D. pulicaria can be limited by dietary P.

This Session Listing

Aquatic Sciences Meeting, Albuquerque 2001

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