Paleoecological studies of mountain lakes

The results of studying four mountain lakes in different climatic zones (in regions of the Kola North and the Western Caucasus) are given. Original methods of paleoecological reconstruction developed by the authors have been used to characterize the main trends and rates in environmental changes at historical scale (by geochemical composition and diatom complexes in bottom sediment layers). Similar processes of modern water enrichment by metals (especially, Cd and Pb) have been determined in the examined lakes. Trends in changes in acid-base balance in The Kola North lakes since the late XIX century have been identified, reflecting the effect of transboundary transport of acid-forming substances from industrial Europe. Studies of diatom complexes in Caucasian lakes showed a rise in the mean annual temperature of lake water during the XX century supposedly by 1.5°C.