Diatom composition and ecological properties of Araban-Yavuzeli Region

The relationships between algae species and environmental variables the ecological preferences of species and biomarker potential of filaqmentpous algae in different aquatic ecosystems of Gaziantep city was investigated from November 2012 to January 2015 using multivariate statistical techniques. Physico-chemical variables showed seasonal variation. Physico-chemical variables showed changes in diffferent aquatic ecosystems. A total of 223 algal taxa were identified, most of them belong to Bacillariophyceae (107 taxa), followed by Chlorophyceae (44 taxa). 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, 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, TDS, kalinity, Na, pH, SO4, conductivity, PO4, temperature, and Ca) played significant (p=0.002) role on the seasonality of species. The first two axes of Canonical Correspondence Analyses (CCA) indicated 95.1 % of the correlation between species and environmental variables and explained 21.3 % of cumulative variance of species data. Frequently counted taxa such as Cyclotella planctonica, C. iris, Fragilaria biceps, and Tetraedron sp. 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. According to the weighted average regression, most phytoplankton species showed unique ecological preferences for different environmental conditions, but especially commonly recorded phytoplankton taxa with cosmopolitan characteristics had relatively high tolerance and broad optimum ranges.