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JOURNAL OF PLANKTON RESEARCH | VOLUME 19 | NUMBER 1 | PAGES 141-148 | 1997
© Oxford University Press
other |
Horizontal distribution of Daphnia pulex in response to toxic and non-toxic algal extracts
Laboratory of Ecology and Animal Systematics, Department of Biology, University of Turku FIN-20014 Turku, Finland 1Institute of Zoology, Department of Animal Ecology, University of Bergen N-5007 Bergen, Norway 2Department of Pharmacy, PO Box 56, University of Helsinki FIN-00014 Helsinki, Finland
Received on December 17, 1996; accepted on June 4, 1996 We studied the horizontal distribution of Daphnia pulex as a response to gradients of toxic extracts of two cyanobacteria, Microcystis aeruginosa and Oscillatoria agardhii and non-toxic extracts of the green alga Scenedesmus obtusiusculus. The experiment was performed in the dark using a flow through system with five chambers. Daphnia pulex aggregated at the inlet of Scenedesmus extract, but showed similar responses to extracts of toxic cyanobactena and food-free medium. Chemical cues seem to affect food search, but do not effect Daphnia pulex's avoidance of toxic algae.