CS36 Ultraviolet Radiation
Date: Friday, June 14, 2002
Time: 11:00:00 AM
Location: Sidney
 
RautioM, Dept. Ecol & Syst., Univ. Helsinki, Helsinki, Finland, milla.rautio@helsinki.fi
Korhola, A, , Dept. Ecol. & Syst., Univ. Helsinki, Helsinki, Finland, atte.korhola@helsinki.fi
 
PHOTOPROTECTIVE PIGMENTATION IN ARCTIC DAPHNIA WITH IMPLICATIONS TO CLIMATE CHANGE
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The depletion of stratospheric ozone and resultant increase in UV-B radiation poses an enormous threat to high-latitude aquatic ecosystems. Here we demonstrate that the occurrence of UV-protective melanin pigmentation in the planktonic crustacean Daphnia is linked to the UV transparency in arctic ponds and lakes in Finnish Lapland. The highest pigment concentration was found in populations of shallow ponds and lakes with low organic carbon content. Pigment synthesisation was extremely low during the long winter and peaked immediately after the ice break-up at the time of the maximum underwater UV-intensity. We propose that the predicted increase in UV irradiance from ozone depletion in the Northern Hemisphere spring, along with the earlier ice break-up associated with Arctic warming are likely to favour the survival of those organisms with the ability to produce UV photoprotective pigments. This may eventually lead to marked alterations in species compositions and food-web interactions in high-latitude aquatic ecosystems.