Heterotrophic bacterioplankton in the Kama reservoirs in summer 2022
M.V. Umanskaya, E.S. Krasnova
Section: Monitoring of natural and anthropogenically disturbed areas
The paper describes the size-morphological structure and spatial distribution of heterotrophic bacterioplankton in the Nizhnekamskoe, Votkinskoe and Kamskoe Reservoirs in August – September 2022. The total abundance of heterotrophic bacterioplankton in the studied reservoirs varied within the range of (1.91–8.74) · 106 cells/mL (on average (3.8±1.2) · 106 cells/mL), biomass – 44.1–190.8 µg C/L (91.0 ± 29.3 µg C/L), which corresponds to the mesotrophiceutrophic level of productivity. The composition of bacterioplankton was dominated by small single free-floating heterotrophic bacteria, mainly cocci and cocobacilli. Unicellular filamentous cells constantly present in the samples during the observation period, and were an integral component of heterotrophic bacterioplankton, despite their small abundance at most stations. In the mouth areas of the tributaries, the number of bacteria was 1.5–2.0 times higher than in the adjacent areas of the reservoirs. This may be due to the fact that mouth areas are a kind of barrier between the tributary and the reservoir, where transformation and accumulation of river flow occur, i.e. they represent ecotones characterized, among other things, by an increase in the abundance of organisms. Aggregated bacterioplankton was mainly associated with detritus particles and made a significant contribution to the total abundance of bacteria, mainly in the mouth areas of tributaries. Picodetritic particles were constantly present in all samples and exceeded the mass of bacterioplankton by 2.8 times, and their greatest number was found in the mouths of tributaries. The water in all reservoirs of the cascade corresponded to the IV (polluted) quality class in terms of the number of bacterioplankton.
Keywords: heterotrophic bacteria, detritus, spatial distribution, the Kama reservoirs’ cascade
Article published in number 2 for 2026 DOI: 10.25750/1995-4301-2026-2-092-099
ISSN 1995-4301
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