Limnoloecology of ecotone lakes in Finnish Lapland – Present and past
Presenta: Liisa Nevalainen
Department of Biological and Environmental Science, University of Jyväskylä, Finland
A set of lakes across north boreal forest to subarctic tundra in Finnish Lapland were investigated for limnoloecological variability, including mapping of catchment properties, limnology, sediment biogeochemistry, and aquatic communities. The aim was to understand high latitude catchment–lake coupling processes, with a focus on terrestrial organic carbon and bio-optics, and systems' vulnerability to climate warming in a spatial and long-term temporal context. The results suggested that the ecotone lakes preserve wide limnological and biogeochemical diversity that is mainly controlled by wetland coverage of the catchments, fueling heterotrophic (dissolved organic carbon) and autotrophic (nutrients) productivity. Nutrients and input of terrestrial organic carbon were also main drivers for community composition, stable isotope fingerprints, and UV-protective pigmentation of aquatic invertebrates. Preliminary down core investigations indicated that the 20th century climate warming has increased terrestrial carbon inputs and enhanced aquatic production relative to the preceding centuries. The results suggested that the complex interactions between climate, catchment vegetation, lake metabolism, and aquatic communities make these shallow ecotone lakes highly prone to climate-induce shifts in organic carbon sequestration.
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