Epipelic Diatoms as Indicators of Water Quality in the Lower Part of River Melet (Ordu, Türkiye)

Phytobenthos includes bioindicator species and is widely used in water ecology studies. Diatoms constitute one of the most important groups of phytobenthos in streams. In particular, these organisms are good indicators in investigations related with determining of water quality in medium and long time. In this study, the epipelic diatom flora of the lower part of River Melet were investigated, the most important source of drinking water in Ordu city. The examination was performed periodically in March-November 2012 and total of 56 taxa were identified. Cymbellales (14 taxa) and Naviculales (16 taxa) ordo constituted 54% of diatom diversity. These were followed by Fragilariales (16%, 9 taxa) Bacillariales (14%, 8 taxa) Surirellales (9%, 5 taxa) Achnanthales (3%, 2 taxa) Eunotiales (2%, 1 taxa) and Melosirales (2%, 1 taxa), respectively. Diatome vulgaris, Melosira varians, Navicula gregaria, N. tripunctata and Nitzschia sigmoidea species were recorded as widespread and intense in the epipelic communities. These species are usually tolerant to organic pollution and are found in β-α- mesosaprobic conditions. According to the obtained results, the lower part of the Melet River has character from pollution towards moderate pollution. In other words, it has II-III. class water quality