Eco-assessment of phytoplankton composition in relation to environmental conditions of saltwater and freshwater lakes in the Konya Closed Basin (Turkey)

Great importance is given to maintaining lentic ecosystems, threatened by human-induced consequences worldwide. The present study hypothesized to assess differences in species-environment relationships and ecological status of 15 lakes (saline water systems, high-altitude freshwater lakes, and other freshwater lakes) in the Konya Closed River Basin using phytoplankton indices throughout wet and dry periods. Results of canonical correspondence analysis separated saline and freshwater (high-altitude) habitats, which were characterized by different phytoplankton species. Total phosphorus (TP), electrical conductivity (EC), nickel-Ni, and altitude were the most influential environmental factors affecting phytoplankton dispersal in these ecosystems. Saline lakes were under pressure of high EC, TP, and Ni, while high-altitude freshwater ecosystems were associated with the elevation. Lake Uyuz, associated with TP and Ni, is characterized by Anabaenopsis elenkinii, Cocconeis pediculus, Euglena viridis, Lepocinclis acus, Lepocinclis ovum, and Lepocinclis oxyuris. Several phytoplankton species like Dunaliella salina, Nitzschia communis, Nitzschia inconspicua, Nitzschia vermicularis, and Navicula cincta were found in saline and saline soda lakes with high EC gradients. Freshwater lakes are characterized by Tabellaria flocculosa, Pinnularia anglica, Fragilaria pararumpens, Eunotia bilunaris, and Pinnularia microstauron. Results of the phyto-assessment displayed a high ecological status for Lake Sülüklü but a bad ecological status for Lake Uyuz. The modified phytoplankton trophic index can be an appropriate phytoplankton metric for determining the environmental conditions of lakes in the Konya Closed system. The Søndergaard metric based on total phytoplankton and cyanobacteria biovolume also supported the ecological statuses of lakes. This work underlined the importance of phytoplankton ecological integration in saline water systems and high-altitude freshwater lakes, as well as the determination of the ecological statuses of various lakes in the semi-arid eco-region.