SS3.09 Climate-Lake Interactions
Date: Wednesday, June 12, 2002
Time: 3:15:00 PM
Location: Colwood
SteinR, Alfred Wegener Institute, Bremerhaven, Germany,
Dittmers, K, , Alfred Wegener Institute, Bremerhaven, Germany,
Fahl, K, , Alfred Wegener Institute, Bremerhaven, Germany,
Niessen, F, , Alfred Wegener Institute, Bremerhaven, Germany,
Stepanets, O, , Vernadsky Institute , Moscow, Russian Federation,
Overall scientific goal of the Russian-German multidisciplinary research project on "Siberian River Run-off (SIRRO)" is the understanding of biological, geochemical and geological processes in relationship to the freshwater and sediment input by the major rivers Ob and Yenisei and its impact on the present and past environments of the estuaries and adjacent inner Kara Sea, Arctic Ocean. Studies concentrate on suspended matter, surface sediments and sediment cores obtained during "Akademik Boris Petrov" expeditions in 1999, 2000 and 2001. Within this approach, sedimentological and organic-geochemical (biomarker) investigations concentrate on the characterisation and quantification of siliziclastic and organic-carbon input and its Holocene variability. Distinct changes in magnetic susceptibility (MS), grain size, organic carbon fractions, and accumulation rates are dominantly related to the post glacial sea-level rise and short-term discharge and climate variability during the last 10,000 Cal. Yrs. BP. Short-term maxima in MS related to warmer climate, enhanced precipitation, intensified weathering/erosion and, thus, increased river discharge, display a frequency of about 300 to 700 years. Several distinct MS minima appear in correlation with cooling events in the North Atlantic and over Greenland as well as an advance of glaciers in southern Norway, e.g., near 8200 Cal. Yrs. BP and during the last about 2500 Cal. Yrs. BP.