How do climate changes affect northern lake ecosystems?
Lakes in the Arctic and the northern boreal areas are sensitive to climate change. A group led by Professor Jan Karlsson at Umeå University will investigate how global warming with increased water temperatures and inflow from land will impact fish stock and the exchange of greenhouse gases in northern lakes.
Professor Jan Karlsson takes water samples at Umeå University’s experimental ponds at Röbäck in Umeå in northern Sweden. Photo: Mattias Pettersson.
“We presume that the course of change won’t be linear, but rather that we’ll find tipping points where there will be a drastic change with large impacts on fish stock and the exchange of greenhouse gases,” says Jan Karlsson.
Northern lake ecosystems work completely different from lakes on more southern latitudes. The lakes are low on nutrients and fish and largely depend on the primary production that takes place on the bottom of the lake. In effect, this makes lakes particularly sensitive to climate change as a warming climate is expected to reduce the important primary production.
A warming climate leads to increased water temperatures and an inflow of nutrients and organic carbon from land. The latter turns the water brown and shadows primary producers on lake bottoms. At the same time, parts of the added organic carbon is decomposed and forms greenhouse gases.
The project combines the latest knowledge in Biogeochemistry and Ecology and uses a combination of various methods. Researchers will make comparative studies of lakes along climate gradients, experiments in artificial, experimental ponds in Umeå and full-size lakes in the inland of Northern Sweden and analyse lake sediment to gain historic data from previous periods of climate change. The method is interdisciplinary and involves ecologists, biogeochemists, molecular biologists and modelers.
The objective is to develop a dynamic ecosystem model to predict future production of fish biomass and the exchange of greenhouse gases in various types of lakes in the North.
“The model is also to be used as a tool in monitoring and management, this for instance in order to assess what lake ecosystems are particularly sensitive to climate change and how sustainable fishing can be carried out,” says Jan Karlsson.
Jan Karlsson is director of the Climate Impacts Research Centre (CIRC).
About the project:
Main applicant: Jan Karlsson, professor at the Department of Ecology and Environmental Science and the Climate Impacts Research Centre (CIRC) at Umeå University Project title: Climate change induced regime shifts in Northern lake ecosystems Awarded grant: SEK 36,970,000 over five years from the Knut and Alice Wallenberg Foundation Co-applicant: Richard Bindler, Sebastian Diehl and Xiau-Ru Wang, all professors at Umeå University; Ann-Kristin Bergström, Åke Brännström and Pär Byström, all associate professors at Umeå University, and David Bastviken, professor at Linköping University.
CIRC conducts both research and education with focus on climate impacts on terrestrial and aquatic ecosystems in Arctic and alpine ecosystems. The aim is to integrate new knowledge in ecology and biogeochemistry to get a more thorough understanding of current conditions and making projections for the future. The operations are placed in the Abisko Scientific Research Station, 100 km northwest of Kiruna in the north of Sweden.