Assessment of water quality of Mustafakemalpaşa stream (Bursa) at two different periods using epilithic diatoms

In this study, it is aimed to determine the biological water quality of Mustafakemalpaşa Stream which is one of the important water resources of Bursa province by using epilithic diatoms. Epilithic diatom samples were collected monthly from October 2016 to September 2017 at two stations on Mustafakemalpaşa Stream, and some physico-chemical variables were measured in stream water. The annual average values of the measured physico-chemical variables were evaluated according to the Surface Water Quality Regulation and water quality classes were determined. The study data were compared with the monthly data obtained from the same study area and the same stations between April 2001 and May 2002, epilithic diatom composition was compared between sampling periods. 97 taxa belonging to 41 genera in 2001-2002 period and 68 taxa belonging to 31 genera in 2016-2017 period were detected in epilithic diatom flora of Mustafakemalpaşa Stream. In both periods, Achnanthidium minutissimum (Kützing) Czarnecki, Amphora ovalis (Kützing) Kützing, Amphora pediculus (Kützing) Grunow, Navicula tripunctata (O.F.Müller) Bory, Navicula veneta Kützing, Nitzschia frustulum (Kützing) Grunow and Rhoicosphenia abbreviata (C.Agardh) Lange-Bertalot are the most important taxa in terms of their relative abundance and recurrence. In this study, Trophic Diatom Index was applied by using epilithic diatoms. According to the results of the Trophic Diatom Index applied in the study, the study area was found to be eutrophic in both sampling periods. When the two sampling periods were compared, it was found that the number of epilithic diatom taxa decreased compared to years. The decrease in the number of diatom taxa over the years has been attributed to the increase in pollution load as a result of human activities. In this study, it is appropriate to use the Trophic Diatom Index to determine the biological water quality and epilithic diatoms are a good indicator for determining water quality.