Seasonal Variations of Phytoplankton Community in Relation to Some Physical and Chemical Parameters in a Temperate Eutrophic Reservoir, Turkey

The çaygören reservoir is fed by the simav streamand the maximum inflow (1300 m^3 sec^-1) occurred in spring and the minimum (about 5.2 m^3 sec^-1) occurred in fall. it has an annual mean water capacity of 392 hm^3 and a total volume of 142.57 hm^3. a total of 192 taxa in 9 divisions were identified. cyclotella meneghiniana kützing, stephanodiscus neoastraea hakansson and hickel of bacillariophyta, gloeotila subconstricta (g.s.west) printz of chlorophyta, mugeotia sp. of streptophyta, cryptomonas pyrenoidifera geitler, plagioselmis nannoplanctica (h.skuja) g.novarino, i.a.n.lucas and s.morrall of cryptophyta, aphanocapsa holsatica (lemmermann) g.cronberg and j.komárek, aphanothece clathrata west and g.s.west and planktothrix sp.of cyanobacteria dominated phytoplankton at least for one season during the observation period. species of cryptophyta dominated phytoplankton during the winter, while chlorophyta and streptophyta species were dominant in the fall. bacillariophyta species dominated phytoplankton in the spring and cyanobacteria were dominant in the summer. the maximum phytoplankton biomass and abundance (106.5 mg l^-1; 273154 individual m^-3) were recorded in summer 2008 at the third station and the minimum biomass and abundance (0.23 mg l^-1; 799 individual m^-3) were recorded in winter 2007 at the second station. the canonical correspondence analysis (cca) and correlation results showed that water temperature, transparency, phosphate, oxidation-reduction potential and water discharge had significant effects (monte carlo test, p<0.05) on the dynamics of dominant phytoplankton of the eutrophic çaygören reservoir.