Can global change determine which zooplankton species will dominate in the Arctic?
Climate models predict that the greatest effect of the global climate changes will occur in the Arctic. The increasing temperatures will affect the metabolism of individual organisms directly and are also likely to cause changes at the ecosystem scale. Temperature preferences differ among species and therefore the geographical distribution of a given species is often temperature dependent. Truly arctic zooplankton species are therefore likely to experience increased competition from species which are expanding their territories northward as a consequence of the increasing temperatures at northern latitudes. Therefore, it is relevant to investigate how the metabolism of arctic and temperate zooplankton changes along a temperature gradient, so that we may better predict which shifts in zooplankton communities the climate changes will incur. The initial hypothesis would of course be, that the arctic species have a higher surplus of energy for growth and reproduction at low temperatures (i.e. <10°C) compared to temperate species. It follows; that when the temperature increases due to climate changes it is likely that the temperate species can outcompete their arctic cousins. One way to test this hypothesis could be to measure respiration rates for arctic and temperate Daphnia species along a temperature gradient using oxygen microelectrodes. The experiments are expected to last 4-6 weeks but a longer period is needed in order to establish cultures of Daphnia and their food as well as to setup and test the entire equipment. The results will eventually provide important information about how climate change may affect the zooplankton of arctic lakes.
|Anvendte metoder:||Lab experiments, measuring feeding activity, respiraton, microscopy|
|Keywords:||Zooplankton, Feeding, Respiration, Foodweb|
|Vejleder(e):||Kirsten S. Christoffersen|