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Cyanobacterial chemical warfare alters zooplankton commuinty composition

Author:
  • Lars-Anders Hansson
  • Susanne Gustafsson
  • Karin Rengefors
  • Lina Bomark
Publishing year: 2007
Language: English
Pages: 1290-1301
Publication/Series: Freshwater Biology
Volume: 52
Issue: 7
Document type: Journal article
Publisher: Wiley-Blackwell

Abstract english

1) Toxic algal blooms widely affect our use of water resources both with respect to drinking water and recreation. However, it is not only humans, but also organisms living in freshwater and marine ecosystems, that may be affected by algal toxins.

2) In order to assess if cyanobacterial toxins affect the composition of natural zooplankton communities, we quantified the temporal fluctuations in microcystin concentration and zooplankton community composition in six lakes.

3) Microcystin concentrations generally showed a bimodal pattern with peaks in early summer and in autumn, and total zooplankton biomass was negatively correlated with microcystin concentrations. Separating the zooplankton assemblages into finer taxonomic groups revealed that high microcystin concentrations were negatively correlated with Daphnia and calanoid copepods, but positively correlated with small, relatively inefficient phytoplankton feeders such as cyclopoid copepods, Bosmina and rotifers.

4) In a complementary, mechanistic laboratory experiment using the natural phytoplankton communities from the six lakes, we showed that changes in in situ levels of microcystin were coupled with reduced adult size and diminished juvenile biomass in Daphnia.

5) We argue that in eutrophic lakes, large unselective herbivores, such as Daphnia, are ”sandwiched” between high fish predation and toxic food (cyanobacteria). In combination, these two mechanisms may explain why the zooplankton community in eutrophic lakes is generally comprised of small forms (e.g. rotifers and Bosmina) and selective raptorial feeders, such as cyclopoid copepods, whereas large, unselective herbivores, such as Daphnia, are rare. Hence, this cyanobacterial chemical warfare against herbivores may add to our knowledge on population and community dynamics among zooplankton in eutrophic systems.

Keywords

  • Ecology
  • microcystin
  • cyanobacteria
  • Daphnia
  • zooplankton
  • toxin

Other

Published
  • ISSN: 0046-5070
Lars-Anders Hansson
E-mail: lars-anders [dot] hansson [at] biol [dot] lu [dot] se

Professor

Aquatic ecology

+46 46 222 41 69

E-C140

50

Professor

NanoLund

14

Research group

Aquatic Ecology

Other projects I´m involved in

Doctoral students and postdocs

PhD students, main supervisor

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