Diatoms in a sediment core of Lake Raifskoye (Volzhsko-Kamsky Nature Reserve, Republic of Tatarstan): lake development over the past 1200 years

Abstract

Studies of the diatom assembly in a 130-cm sediment core from Lake Raifskoye reveal 79 taxa of diatoms ranking below the genus of two classes (centric - 14, pennate - 65). 14C, 210Pb and 137Cs dating results show that the sediment core covers a continuous deposition since 1200 cal. yr BP. During the development of the lake, three periods were identified. In the range of 600-1200 years ago unfavourable conditions for the development of diatoms were noted, presumably due to low environmental temperatures. Period from 150-450 years ago reflects good conditions for the development of diatoms and, as a consequence, an increase in the productivity of algal communities in the lake against the backdrop of rising air temperatures. In the third, modern period, the processes of increasing the productivity of algal communities continue, which can also be associated with an increase in air temperature.