Biodiversity and food webs in arctic lakes
A vast majority of arctic lakes have very low nutrient concentrations and are covered by a 1-2 m thick layer of ice most of the year, typically for 8-10 months. The ice itself and a snow layer of varying thickness (0-0.5 m) prevent the light from penetrating into the water during most of the year. No or little primary production is likely to take place for a majority of the year. Life under the ice is therefore limited to species that either have stored resources or can survive without much food over longer periods. Contrary, light is plentiful during the short summer but the combination of a low average summer temperature and limited nutrient availability allow s only for a low primary production. Thus, even during summer arctic lakes have rather few species and lower biomasses compared to temperate lakes. Nevertheless, lots of activities are taken place in lake and pond during the short Arctic summer, as plankton populations must reproduce efficiently in order to secure the survival of the species. This call for a number of scientific questions such as: - Which specific physiological adaptions are needed to ensure a successful growth and reproduction? - How is sufficient food intake secured during summer and winter? - To which extend can lack of edible food be tolerated? - What is the role of interactions within the whole food web for the function of the plankton community? - Is it possible that dropping from geese populations or bird cliffs can change the trophic state of lakes and ponds? - Can man-made eutrophication be a problem? These subjects can be addressed by experimentally by running lab setups under different light and temperature conditions to test the growth success of e.g. Daphnia. Students are also offered the opportunity to work with these subjects based on the literature and/or existing monitoring data. It might even be possible to include shorter or longer stays at Arctic Station (part of University of Copenhagen) in West Greenland or at the University Centre in Svalbard at different seasons to do fieldwork. While the supervisor provides field equipment, knowhow and instructions, please note, that if you aim for doing field work in the Arctic is rather expensive. Therefore, be prepared to find funding for you own transportation and lodging. The specific expenses depends on where to go and for how long but a rough estimate is 15.000 Dkr for 2-4 weeks. Thus, it is advisable to start planning such a project a year ahead of the actual bloc(s) it will run. I´m happy to assist you with more information.
|Anvendte metoder:||Microscopy, water chemistry analyses, chlorophyll, isotopes, experimental setups|
|Keywords:||Arctic lakes, Food web, Biodiversity, Interactions|
|Vejleder(e):||Kirsten S. Christoffersen|