Paleolimnological studies of tundra lakes in the pechora delta (Nenets autonomous region, Russia)

© SGEM2018. Warming of the climate system is unequivocal, and since the 1950s, many of the observed changes are unprecedented over decades to millennia. Polar region of the Russia not only play the leading role in world climatic system, but also quickly, with high sensitivity react to climatic changes. Investigation of lake from arctic region has an extreme importance for understanding of the modern environmental processes and their influence on northern ecosystems and biological diversity of these regions. Limnological characteristics and recent environmental history of twelve remote tundra lakes in the Pechora Delta (Nenets Autonomous Region, Russia) were investigated using both limnological and palaeolimnological methods with particular attention to subfossil Cladocera. All the lakes were sallow, alkaline or neutral, with an average pH of 8.2 and characterized by a low mineralization level. In total five cores were obtained in summer 2017, sliced into 1.0 cm-thin samples in the field and further investigated using palaeolimnological methods. Tree cores were freeze-dried and analysed for210Pb dating.210Pb results indicate a relatively stable, recent sedimentation rate of about 0.02-0.03 cm/a. The species distribution of Cladocera remains in recent sediment layers was similar to that observed in contemporary water samples. Subfossil Cladocera assemblages are characterized by the dominance of Chydorus sphaericus s.l., Bosmina (Eubosmina) longispina, Daphnia pulex agg. Paleolimnological investigation has shown that the major compositional changes in cladoceran and other paleoindicators are synchronous