Algae composition and ecological properties of aquatic ecosystems belong to Aras basin

Phytoplankton, one of the ecological quality elements proposed by the European Union Water Framework Directive to be used for the ecological status assessment of aquatic ecosystems. The aim of this study was to determine phytoplankton composition, evaluate the ecological preferences phytoplankton groups, and assess the ecological status of Lakes of Çildir, Balık, Aktaş, Aygır and Deniz in the Aras basin during summer-autumn 2014 and spring 2015. The highest values of orthophosphate, nitrate, nitrite, electrical conductivity and total suspended solids, total phosphorus nitrogen were found in the Lake Aktaş. A total of 74 species were identified during the study. Cocconeis placentula, Pediastrum boryanum, Monorophidium arcuatum, Fragilaria ulna, Cymbella affinis and Cyclotella bodanica were commonly found species. A canonical correspondence analysis (CCA) and weighted average regression were used to examine the relationships between environmental factors and phytoplankton species in the lakes. Environmental factors play significant roles on the distribution of phytoplankton community. Carlson trophic index and OECD criteria were used to evaluate throphic states of these lakes. Phytoplankton trophic index and Mediterranean phytoplankton trophic index were performed to evaluate the ecological quality status. Results of PTI and Med-PTI indicated that the studied ecosystems were mostly at good and moderate ecological status.