Journal of Siberian Federal University. Biology / Diatom Assemblages in Lake Turgoyak Sediments: The Lake Ecosystem’s Response to Holocene Climate Change

Full text (.pdf)
Issue
Journal of Siberian Federal University. Biology. 2025 18 (3)
Authors
Maslennikova, Anna V.
Contact information
Maslennikova, Anna V. : South Urals Federal Research Center of Mineralogy and Geoecology UrB RAS Miass, Russian Federation; ; ORCID: 0000-0003-0434-4372
Keywords
diatom assemblages; Holocene; climate change; paleolimnological record; lake; Urals; human impact
Abstract

Changes in the ecosystem of the deep oligotrophic Lake Turgoyak located on the eastern slope of the Southern Urals may be associated with both anthropogenic impacts and natural processes. To identify natural variability of lake ecosystem parameters, as well as factors and mechanisms influencing the ecosystem’s development, paleolimnological research was carried out. The study aimed to determine the response of Lake Turgoyak to the climate change that occurred from the end of the Late Glacial period to the present based on diatom analysis of a sediment core. The study of diatom assemblages allowed us to identify major stages of lake development. Approximately 12,500–11,000 cal BP, Lake Turgoyak was slightly brackish with a well- developed macrophyte belt. The lake’s water salinity significantly decreased around 11,000 cal BP. The duration of summer stratification increased between 7,800 and 2,500 cal BP. A rise in the lake water level and a decrease in water pH occurred around 2,500 cal BP. A differential response of the lake’s ecosystem to the periods of Holocene climate warming was established. For example, the climate change at the beginning of the Holocene led to increased water salinity and decreased saprobity due to the influence of macrophytes. The current climate change, similar to the Atlantic warming period, was characterized by an extended summer stratification period followed by nutrient depletion in the epilimnion. Changes in diatom assemblages in the period of antropogenic impact did not conform to the natural variability of the lake’s ecosystem. Despite the lake’s saprobity decreasing since the mid-20th century, this period marked the first-ever throughout its history appearance of alpha-mesosaprobes in the diatom assemblages. Additionally, the Shannon diversity index reached its maximum values

Pages
327–346
EDN
BOCVWY
Paper at repository of SibFU
https://elib.sfu-kras.ru/handle/2311/157489

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