Evidence of global warming observed in arctic lakes

The sediments present at the bottom of the lakes are good indicators of the biological activity through the ages because the organisms living in the polar regions are very sensitive to the least variation of temperature.

An international study focusing on the polar regions shows that climate change is causing ecological reorganization and a change of species that would have started 150 years ago.

The study was conducted by 26 researchers who studied 55 lakes located in Canada, in
Russia, Spitsbergen (Norway) and Lapland (Finland). The changes appear as much in the composition of the species as in their diversity, and the variation is greater in the more northerly regions. This observation is corroborated by climate models that show that global warming is more accentuated at the poles. The impact of human activity can not be at the root of these variations. In fact, unlike temperate regions, there is very little agriculture in these areas, apart from a few herds of reindeer and caribou. Polar regions suffer from precipitation containing
heavy metals, acidic molecules and nutrients. This phenomenon is largely confined to the second half of the twentieth century, which is very much later than the beginning of the reorganization observed in this study.

Read also: Eco-construction section for downloads

contacts:
- Teacher. Atte Korhola, climate change specialist,
Coordinator of CHILL-10,000.
Department of Biology and Environmental Sciences, University of
Helsinki,
65 Mailbox (Viikinkaari 1), FIN-00014 University of Helsinki, Finland
- tel: + 358 9 191 57 840 - email: att.korhola@helsinki.fi
Sources: Smol et al. (2005) Climate-driven diet shifts in the biological
communities of artic lakes, PNAS, early edition February
Editor: Marie Aronson

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