The sediments present in lake bottoms are good indicators of biological activity throughout the ages because the organisms living in polar regions are very sensitive to the slightest variation in temperature.
An international study centered on the polar regions shows that climate change is causing an ecological reorganization and of a kind that would change starts 150 years ago.
The study was conducted by researchers who studied 26 55 lakes situated in Canada,
Russia, in Spitsbergen (Norway) and Lapland (Finland). The changes appear both in the composition of species in their diversity and variation is greater in the more northern regions. This observation is corroborated by climate models that show that global warming is more pronounced at the poles. The impact of human activity can not be at the origin of these variations. In contrast to temperate regions, there is very little agriculture in these areas, apart from a few herds of reindeer and caribou. The polar regions are suffering from precipitation containing
heavy metals, acids molecules and nutrients. This phenomenon is largely confined to the second half of the twentieth century is very posterior to the beginning of the reorganization observed in this study.
- Teacher. Atte Korhola, specialist in climate change,
Department of Biology and Environmental Sciences, University of
PO Box 65 (Viikinkaari 1), FIN-00014 University of Helsinki, Finland
- Tel: + 358 9 191 57 840 - email: firstname.lastname@example.org
Sources: Smol et al. (2005) Climate-driven diet shifts in the biological
Communities of artic lakes, PNAS, Early Edition February
Editor: Mary Aronson