Limno-assessment of phytoplankton composition in relation to environmental conditions of lakes in Antalya River Basin

Abstract

Human-induced factors and global climate change have threatened freshwater resources. Phytoplankton assessments have been used to predict impairment of lentic ecosystems. The aim of the study was to assess species-stressor associations and the ecological status of eight lakes in the Antalya River basin using phytoplankton indices throughout wet and dry periods according to the Water Framework Directive. The analysis of similarities test revealed a significant difference in the composition of species between the wet (May) and dry (August and November) seasons (p < 0.05). The canonical correspondence analysis indicated that alkalinity, electrical conductivity (EC), pH, total phosphorus (TP), and arsenic (As) had significant effects on the distribution of phytoplankton among lakes. Lake Titreyen was associated with high EC and characterized by pollution-tolerant species. Lake Egri was under the pressure of TP and As, while Lake Kirkgoz was associated with relatively high alkalinity. The findings of the phyto-assessment indicated that Lake Egri is in good ecological condition, while Lake Duruca is in high ecological condition. Sondergaard metric based on the cyanobacteria biovolume values indicated that Lake Egri had a moderate ecological status, whereas Lake Duruca had a good environmental condition. To evaluate the ecological status of lakes, the modified phytoplankton trophic index could be a suitable metric. Results of the present study underlined the responses of phytoplankton species in various lakes to environmental variables, which provide crucial ecological information about their ecology and help in the estimation of the ecological status of lakes.