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Size-selective predation on pelagic microorganisms in Arctic freshwaters

Författare:
  • S Bertilsson
  • Lars-Anders Hansson
  • Wilhelm Granéli
  • A Philibert
Publiceringsår: 2003
Språk: Engelska
Sidor: 621-631
Publikation/Tidskrift/Serie: Journal of Plankton Research
Volym: 25
Nummer: 6
Dokumenttyp: Artikel i tidskrift
Förlag: Oxford University Press

Abstract english

Herbivorous zooplankton may have a pronounced influence on pelagic microorganisms in Arctic freshwaters. We quantified experimentally the size-selective feeding of several zooplankton groups on pelagic microorganisms in high Arctic tundra systems. Our experiments and field study focused on dominant herbivores in Arctic freshwaters, including the cladoceran Dophnia, the copepod Diaptomus and the anostracan Branchinecta, and their effects on prey ranging in size from bacteria to large phytoplankton. Grazing experiments showed that Dophnia were effective predators on all types of prey, whereas Diaptomus grazed preferentially on larger phytoplankton with low clearance rates for bacterial cells. Further analysis by flow cytometry indicated that Diaptomus grazed selectively on the largest bacteria. In contrast to the results obtained in the controlled experiments, Arctic lakes and ponds with a zooplankton community dominated by Dophnia had a higher bacterial production and abundance than systems not dominated by this grazer. This may indicate that the stimulatory effect of grazers on bacterial growth is more pronounced in natural systems, or that factors other than zooplankton grazing are more important in regulating bacterial abundance and production in natural systems. Although Arctic waters differ considerably from temperate systems with respect to temperature and light regime, herbivore-prey dynamics as well as the bacterial response to temperature appear to be similar between the climatic regions.

Keywords

  • Ecology

Other

Published
  • ISSN: 0142-7873
Wilhelm Granéli
E-post: wilhelm [dot] graneli [at] biol [dot] lu [dot] se

Professor emeritus

Akvatisk ekologi

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