Composition and ecological characteristics of diatoms in the northern aegean basin running waters

Phytobenthos is an important biological quality element suggested by the European Union Water Framework Directive (WFD) in the determination of ecological status of aquatic ecosystems. The study aimed to determine the diatomic composition and evaluate the water quality and ecological conditions of 18 running water ecosystems in the Northern Aegean Basin based on diatomic metrics. Diatom and water data were sampled during four seasons (summer and autumn 2014, and spring and summer 2015) according to the WFD standarts methods. A total of 80 diatom species were identified in the water bodies during the study period. Cocconeis placentula, Didymosphenia geminata, Gomphonema parvum, Navicula oppugnata, Cymbella excisa, Ulnaria ulna, Diatoma vulgaris and Navicula cryptocephala were the commonly found species. The relationship between diatom species and environmental variables was examined using the canonical correspondence analysis (CCA) and Monte Carlo permutation test. Temperature, dissolved oxygen, TP, salinity, PO4, electrical conductivity, and total nitrogen had an effective role in the distribution of diatom species during the study. The ecological status and water quality of sampling stations in the North Aegean Basin were evaluated using the trophic index Turkey (TIT) and the trophic index (TI) indices. The TIT index showed a high correlation with logTP and could be an appropriate diatomic metric for evaluating the ecological status of water bodies. Key words: Running water, Canonical, Diatom, North Aegean Basin