Estimation of Long-Range Changes in the Ecosystems of the Upper and Middle-Stream Irtysh on the Basis of Phytoplankton Development Indices
O. P. BAZHENOVA
Abstract
The data of long-term investigations of the Bukhtarma reservoir and the mid Irtysh revealed substantial changes in the species composition, structure and abundance of phytoplankton, which allowed us to determine the directions of changes in the ecosystem. Eutrophication, which started in the Bukhtarma reservoir in late 1970s, got accelerated and occupied the mid Irtysh. The river ecosystem survives ecological stress. The Bukhtarma reservoir is in the state of ecological modulation according to the indices of phytoplankton development; however, the enhancing pollution with organic substances brings about the threat to the stability of the ecosystem.
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