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Relaxed circadian rhythm in zooplankton along a latitudinal gradient

  • Lars-Anders Hansson
  • E Becares
  • M Fernandez-Alaez
  • C Fernandez-Alaez
  • T Kairesalo
  • MR Miracle
  • S Romo
  • D Stephen
  • K Vakkilainen
  • W van de Bund
  • E van Donk
  • D Balayla
  • B Moss
Publishing year: 2007
Language: English
Pages: 585-591
Publication/Series: Oikos
Volume: 116
Issue: 4
Document type: Journal article
Publisher: Wiley-Blackwell

Abstract english

To test whether aquatic invertebrates are able to adjust their diel migratory cycle to different day length and presence of predators, we performed standardized enclosure experiments in shallow lakes at four different latitudes from southern Spain, with strong night-day cycles, to Finland where daylight is almost continuous during summer. We show here that nearly continuous daylight at high latitudes causes a relaxation in diel migratory behaviour in zooplankton irrespective of predation risk. At lower latitudes, however, similar conditions lead to pronounced diel rhythms in migration. Hence, zooplankton may show local behavioural adaptations in their circadian rhythm. They are also able to make risk assessments as to whether diel migration is beneficial or not, manifested in a lack of diel migration at near constant daylight, irrespective of predator presence. Our results provide an additional explanation to previous knowledge regarding diel migrations among aquatic invertebrates by showing that both physical (light) and biological (predation) factors may affect the migratory behaviour.


  • Ecology


  • ISSN: 1600-0706
Lars-Anders Hansson
E-mail: lars-anders [dot] hansson [at] biol [dot] lu [dot] se


Aquatic ecology

+46 46 222 41 69






Research group

Aquatic Ecology

Other projects I´m involved in

Doctoral students and postdocs

PhD students, main supervisor

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