Record of the recent ecosystem events in lake Karakel on the basis of redeposited diatom assemblages
This study provides an analysis of data on diatom assemblages from bottom sediments in Lake Karakel (the Karachay-Cherkess Republic). The sediment cores for analysis were collected in the deepest parts of the lake. The method of graphical analysis of diatom assemblages was applied. We discussed perspectives of using this new method for paleoecological reconstructions. The results of isotopic dating were used. According to the structure of diatom assemblages we distinguished the periods of natural sedimentation in the lake. Several time intervals with the dominance of redeposited processes were established. Redeposited diatom assemblages are determined by characteristic variations of taxonomic proportions. In addition, we revealed the stages of lake ecosystem restoration after mudflows and other negative impacts. For these stages the main characteristic features in the taxonomic structure of diatom assemblages were distinguished. Our results are confirmed by other methods of lake sediment analysis (geochemical and lithological methods).