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Biogeochemical Activity and Microbial Community Structure in the Water Column and Surface Sediments of a Dune Lake Chabyda in Central Yakutia.

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Bibliographic Details
Title: Biogeochemical Activity and Microbial Community Structure in the Water Column and Surface Sediments of a Dune Lake Chabyda in Central Yakutia.
Authors: Savvichev, A. S.1 (AUTHOR) savvichev@mail.ru, Kadnikov, V. V.2 (AUTHOR), Rusanov, I. I.1 (AUTHOR), Samylina, O. S.1 (AUTHOR), Beletsky, A. V.2 (AUTHOR), Gabysheva, O. I.3 (AUTHOR), Gabyshev, V. A.3 (AUTHOR), Kosyakova, A. I.1 (AUTHOR), Zakharova, E. E.1 (AUTHOR), Pimenov, N. V.1 (AUTHOR)
Source: Microbiology (00262617). Dec2025, Vol. 94 Issue 6, p948-965. 18p.
Subject Terms: *BIOGEOCHEMISTRY, *MICROBIAL communities, *ORGANIC compounds, *METHANE, *SAND dunes, *CYANOBACTERIAL blooms, *LAKES
Abstract: Investigations were conducted on the biogeochemical activity of microorganisms and the structure of microbial (bacterial and archaeal) communities in the water column and surface sediment layer of the dune Lake Chabyda (Central Yakutia, Republic of Sakha). It was shown that the rate of primary photosynthetic production (PP, up to 1.1 mg L–1 day–1) reached the levels typical of eutrophic lakes. The study was carried out during a cyanobacterial bloom dominated by Microcystis sp. and Dolichospermum lemmermannii. Total bacterial abundance reached 107 cells mL–1. Bottom sediments of Lake Chabyda were represented by sapropels extremely rich in organic matter (38–43.7%). Microorganisms of the methane cycle dominated in the microbial communities of the bottom sediments. Methanotrophic bacteria (predominantly Methylococcaceae and Methylomonadaceae) accounted for up to 8.3%, and methanogenic archaea (mainly Methanobacterium, Methanoregula, and Methanosaeta) accounted for up to 20% of the total community. Methanogenesis turned out to be the main process completing microbial degradation of organic matter in the sediments. The predominance of methanogenesis over sulfate reduction was associated with the low concentration of sulfates. The sediments were characterized by high rates of aerobic methane oxidation, leading to a significant decrease in methane concentration from depth to the surface. Thus, during the summer season, a microbial community develops in the organic-rich sediments of the dune Lake Chabyda, forming an efficient microbial biofilter that significantly decreases the flux of methane released during seasonal thawing of methane-bearing permafrost into the lake water column and, subsequently, into the atmosphere. [ABSTRACT FROM AUTHOR]
Database: Academic Search Index
Description
Abstract:Investigations were conducted on the biogeochemical activity of microorganisms and the structure of microbial (bacterial and archaeal) communities in the water column and surface sediment layer of the dune Lake Chabyda (Central Yakutia, Republic of Sakha). It was shown that the rate of primary photosynthetic production (PP, up to 1.1 mg L–1 day–1) reached the levels typical of eutrophic lakes. The study was carried out during a cyanobacterial bloom dominated by Microcystis sp. and Dolichospermum lemmermannii. Total bacterial abundance reached 107 cells mL–1. Bottom sediments of Lake Chabyda were represented by sapropels extremely rich in organic matter (38–43.7%). Microorganisms of the methane cycle dominated in the microbial communities of the bottom sediments. Methanotrophic bacteria (predominantly Methylococcaceae and Methylomonadaceae) accounted for up to 8.3%, and methanogenic archaea (mainly Methanobacterium, Methanoregula, and Methanosaeta) accounted for up to 20% of the total community. Methanogenesis turned out to be the main process completing microbial degradation of organic matter in the sediments. The predominance of methanogenesis over sulfate reduction was associated with the low concentration of sulfates. The sediments were characterized by high rates of aerobic methane oxidation, leading to a significant decrease in methane concentration from depth to the surface. Thus, during the summer season, a microbial community develops in the organic-rich sediments of the dune Lake Chabyda, forming an efficient microbial biofilter that significantly decreases the flux of methane released during seasonal thawing of methane-bearing permafrost into the lake water column and, subsequently, into the atmosphere. [ABSTRACT FROM AUTHOR]
ISSN:00262617
DOI:10.1134/S0026261725602751