CS16 Harmful Algal Blooms
Date: Wednesday, June 12, 2002
Location: Poster Session - VCC
GustafssonS, Limnology, Dept. of Ecology, Lund University, Lund, Sweden, Susanne.Gustafsson@limnol.lu.se
Hansson, L, , Limnology, Dept. of Ecology, Lund University, Lund, Sweden, Lars-Anders.Hansson@limnol.lu.se
Practise makes perfect toxin tolerance in experienced Daphnia
In the evolutionary arms race between consumers and prey, an almost indefinite array of adaptations has been developed. In aquatic ecosystems, many herbivorous zooplankton species have developed physiological and behavioural adaptations to avoid being affected by toxic cyanobacteria, such as selective feeding, formation of resting eggs and tolerance to algal toxins. Here, we experimentally test if previous exposure to a toxic strain of cyanobacteria (Microcystis) affects survival, growth and reproduction of a common herbivore, Daphnia magna, during a subsequent exposure. Three different populations of Daphnia magna were each divided into two parts, were one part was fed toxic Microcystis and the other part non-toxic food. After four weeks we compared the ability of the two parts of the population to deal with toxic Microcystis by assessing survivorship, growth, and reproduction. The ability of Daphnia magna to successfully cope with toxic cyanobacteria was improved when the animals had experienced earlier exposure to toxic cyanobacteria. This conclusion suggests that Daphnia repeatedly exposed to cyanobacteria in their natural habitat, may be less affected by the toxin than previously non-exposed Daphnia.