ICES CM 2011/B:20 Changes in the phytoplankton of the Bay (eastern Gulf of ) in the area of port construction

Olga B. Maximova State Research Institute on Lake and River Fisheries (GosNIORKh), nab. Makarova 26, 199073 St. Petersburg,

Vyborg Bay

The phytoplankton is one of the important indicators of ecological status of the water port construction body. In the last decades the active hydroengineering works were carried in the .

At the first period of the works in 1997- 1999 phytoplankton quantitative development in the water area near constructing port Vysotsk corresponded the level of mesothrophic water body. The Thus, in the last decades phytoplankton abundance varied from 39 the phytoplankton to 79 millions cells/l, biomass – from 2 to 4 development in the study g/m3. The blue-green algae constituted the area increased up to major (50%) portion of biomass eutrophic level. This (Limnothrix planctonica, Oscillatoria increase was accompanied limosa, Phormidium dichtyothallum, by enhance of blue-green Planktolyngbya subtilis, Planktothrix algae role. By contrast, role rubescens, Pseudanabaena limnetica, of freshwater green algae Anabaena flos-aquae, A. spiroides, declined. The changes in Anabaenopsis elenkinii, Aphanizomenon phytoplankton probably flos-aquae, A. flos-aquae f. Gracile). Biomass of phytoplankton (g/m3) in Concentrations of chlorophyll-a (а), were caused by natural Chlorophyll “a” concentration was 8–9 the Vyborg Bay in 1997-1999 chlorophyll-в (b), chlorophyll-с (с) factors (more intensive 3 and carotinoides (k) in the Vyborg mg/m . Bay in 1997-1999 inflow of salt and nutrients- reached deep waters from western ) as In 2008-2010 in this area phytoplankton well as increase of abundance varied from 70-193 millions anthropogenic impact 3 cells/l, biomass – from 5 to10 g/m . The mainly connected with blue-green algae constituted about 80% additional nutrients supply of total biomass (Planktothrix agardhii, from bottom during Limnothhrix planctonica, Planktolyngbya hydroengineering works. subtilis, Aphanizomenon flos-aquae, Gomphosphaeria lacustris). The freshwater green algae Dictyosphaerium pulchellum, Sphaerocystis schroederi and For further information Tetraedron spp. disappeared. Chlorophyll Please contact [email protected]. “a” concentration was in the range of 15- 30 mg/m3.

Biomass of phytoplankton (g/m3) in Concentrations of chlorophyll-a (а), the Vyborg Bay in 2008-2010 chlorophyll-в (b), chlorophyll-с (с) and carotinoides (k) in the Vyborg Bay in 2008-2010