Mw. G. (Gissell) Lacerot Silveira, MSc: Effects of climate on size structure and functioning of aquatic food webs

  Nieuws
  Vaknieuws
  Wagenings commentaar
  Dossiers
  Perskamer
  Archief
  Agenda
  2012
  2011
  2010
  2009
  2008
  2007
  2006
  2005
  2004
  2003
  2002
  2001
  2000
  1999
  Nieuws
  RSS
  Agenda
  Open dagen
  Congressen en symposia
  Cursussen
  Promoties & Oraties

6 apr 2010 13:30
Onderdeel: Wageningen University
Locatie: Aula, gebouw 362, Gen. Foulkesweg 1, Wageningen
Organisatie: Wageningen University
Promotor: prof.dr. M. Scheffer (Aquatische ecologie en waterkwaliteitsbeheer)
Co-Promotor: Dr.ir. M.F.L.L.W. Lurling

 Freshwater of good quality is a limited resource. Excessive algal development depends on nutrient load and also the potential of algal control through the aquatic food chain (“trophic cascade”). Algae biomass can be kept low by zooplankton. However, when fish predation is strong, large-bodied zooplankters-like water fleas-disappear and only small species remain, which are less effective at controlling algae. In temperate lakes this insight led to the use biomanipulation to improve water quality. It implies that fish density is reduced to increase the abundance of water fleas. However, these mechanisms work quite differently in (sub)tropical lakes, and might be altered in temperate lakes due to climate change. To answer this question we studied 83 lakes along a latitudinal gradient on the east coast of South America. My research shows that the average body size of fish communities decreases with latitude. Also, while in cold lakes large fish are often piscivores, in warm lakes many large fish eat the same as small fish do. Thus, control of small fish by large fish might be weaker in warmer climates. Just as fish, the body size of zooplankton decreases from cold to warm climates being small fish predation the main cause of this phenomenon. These results provide an indication of the way in which climatic change may affect water quality of shallow lakes.
Print dit agenda item