Diatom from the Late Holocene bottom sediments of Peyungda and Zapovednoye Lakes (Evenkia, Russia)

As part of a biostratigraphic study in the taiga zone of southern Evenkia (Krasnoyarsk Territory, Russia) within the territory of the state nature reserve “Tungussky,” aimed at reconstructing paleoecological conditions of the region and as a continuation of comprehensive research on diatoms communities in the bottom sediments of various water bodies across the country initiated by diatomologists back in the first half of the last century in the USSR, an analysis was conducted of Late Holocene bottom sediments of Peyungda and Zapovednoye lakes. In total, 248 taxa below genus rank were identified belonging to 66 genera and 27 families. Similarities and differences in the composition of the diatom community in lake-bottom sediments of Lake Zapovednoye and Lake Peyungda have been revealed. The degree of similarity in species composition turned out to be high — 69%. Common trends in the development of these lakes corresponding to identical time frames have also been observed. In Lake Peyungda, which spans nearly 4,500 years, evidence has been found for the beginning of the Meghalayan stage of the Holocene epoch associated with the onset of prolonged drought approximately in 2250 BP through sustained increases in the abundance of thermophilous species such as stagnant-streaming waters Aulacoseira ambigua (Grunow) Simonsen and stagnant water specie Discostella stelligera (Cleve & Grunow) Houk & Klee.