Water Quality and Biodiversity of Benthic Animals in the Neva Estuary Under Anthropogenic Stress (in English)

Balushkina E. V., Golubkov S. M.

188 taxa of benthic animals were recorded in the Neva estuary in 1994—2015. At present, zoobenthic communities in the estuary are dominated by eurybiont indicator species inhabiting “polluted” and “dirty” waters. We used integrated index IP’ specially devised for water-bodies and rivers of the north-western Russia to assess the water quality and a state of ecosystems of the Neva estuary. It bases on structural parameters of zoobenthic communities and makes it possible to take into consideration the pollution by toxic and organic substances. On average the water quality of the Neva Bay assessed from IP′ values was relatively stable during 1994—2015. It was assessed as «polluted» with exception for 2006 and 2015 caused by large-scale dredging works. The average number of zoobenthic species in the Neva Bay increased during the period of 1982—2015 almost 2 times from 11±1 in 1982 to 20±2 species on a single station in 2014. Average values of Shannon’s indexes of benthic animals in the Neva Bay increased by one and half from 2±0.1 in 1982 to 3.0±0.3 bit/ind. in 2014. In 1994—2015 values of species richness and Shannon’s index, average for the Resort zone of the eastern Gulf of Finland, varied from 5±0.6 to 11±2 species at single station, and from 1.1±0.2 to 2.1±0.3 bit/ind. that were much lower than in the Neva Bay. This is caused not only by the influence of salinity, but also by the more intensive pollution of this zone.

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