Future Lake Food Webs in Subarctic Have More Biomass and Contain More Omega-3 Fatty Acids


Subarctic regions are facing rapid changes in climate and land-use intensity.

Subarctic regions are facing rapid changes in climate and land-use intensity. An international research team recently completed an investigation to see how these changes are affecting the food webs and fish communities of lakes in northern Finland. Biomasses and omega-3 fatty acids, EPA and DHA, were determined from the algal producers at the base of food web to large carnivorous fish from 20 lakes along a pronounced climatic and productivity gradient. Increasing nutrient load and rising temperature shift food webs towards murky water adapted communities.

An international research team measured amount of fish and invertebrates from 20 subarctic lakes along climate and productivity gradient and determined the nutritional quality of organisms in each lake by measuring valuable omega-3 fatty acids, EPA and DHA, from primary producer algae communities to top predators. Researchers found major differences in the clear and murky water communities. Increasing temperature and productivity increased biomass of algal and cyprinid fish communities.

Professor Kimmo Kahilainen from University of Helsinki, Lammi Biological Station, coordinated this lake research program. “What we find in these food webs was community shift from clear water to murky lakes. We get a lot of fish from blue-green algal covered lakes, but there were no salmonid fishes anymore and the fish catch consisted almost exclusively of roach,” says Kahilainen.

Read more at: University of Helsinki

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