Algae composition and limno-ecological properties of Alleben reservoir

The relationship between algae species and environmental variables in Alleben Reservoir was investigated monthly from April 2012 to June 2013 using multivariate statistical techniques. The reservoir indicating water thermal stratification in April ? October 2012 period and April 2013. Complete water circulations in October 2012 ? March 2013 period, indicated that the reservoir has monomictic characteristic. A total of 232 algal taxa were identified. Bacillariophyceae (57.0 %) was the most dominant group in terms of biovolume, followed by Dinophyceae (18.54 %) and Chlorophyceae (12.99 %) in the reservoir. Biovolume peaks in Alleben Reservoir were mainly caused by the most dominant species such as Cyclotella planctonica, C. iris, Peridinium cinctum, Fragilaria biceps, Tetraedron sp. and Dinobryon divergens. Changes in environmental gradients significantly influenced the ecological preferences of species and phytoplankton abundance in the reservoir. Most effective explanatory factors (in descending order, salinity, conductivity, pH, temperature, TDS, DO, Ca, PO4, Na, SO4, Mn and Mg) played significant (p=0.002) role on the seasonality of species. The first two axes of Canonical Correspondence Analyses (CCA) indicated 92.8 % of the correlation between species and environmental variables and explained 37.1 % of cumulative variance of species data. Frequently counted taxa were found closer to center of CCA ordination seemed a wide range of tolerance levels of these species to the changes in ecological conditions in the lake. The dominant phytoplankton organisms in Alleben Reservoir belong to 6 functional groups: A, D, E, J, LO, and LM. Key Words: Alleben Reservoir; CCA; Ecology; Optimum and Tolerance; Algae.