Phyto- and zooplankton community of Usinskiy Bay and adjacent waters of the Kuibyshev Reservoir during the blooms starting
O.V. Mukhortova, N.G. Tarasova, V.S. Zhikharev
Section: Monitoring of natural and anthropogenically disturbed areas
The article presents the results of studies the plankton community (phyto- and zooplankton) of the Usinskiy Bay (UB) and the adjacent water area of the Priplotinnyy (near-dam) reach (PR) during the blooms starting. We found that favorable conditions for the blooms development were formed in the UB and PR water areas – sufficiently high temperature and a slightly alkaline environment. The UB plankton community has greater species richness than the PR one. Phytoplankton abundance and biomass varied widely: 2.31–149.52 million cells/L and 0.53–13.15 mg/L, respectively. Depending on the plankton community structure the studied area can be divided into three zones: reservoir (including the river estuary), transitional, and the bay. During the studies period Cryptophyta prevailed in the PR phytoplankton, and Cyanobacteria were predominant in the UB. The blooms phenomenon with a level from “moderate” to “intense” was recorded only at two sampling stations, remote from the Kuibyshev reservoir. Zooplankton abundance and biomass varied widely: 78–579 thousand specimens/m3 and 0.61–2.33 g/m3, respectively. The nauplial and copepodite stages of Heterocope caspia Sars, 1897 (Copepoda) dominated in zooplankton of the reservoir, while its adults prevailed in the UB. At farthest from the Usa River estuary sampling stations, there was a change in the share of the main zooplankton taxa: an increase of the rotifers share and a decrease in branched crayfish share.
ISSN 1995-4301
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