Determination of tintinnid (Protozoa: ciliophora) species and ecological variables affecting their distribution in the ecosystem of the golden horn estuary

In this study, which was carried out to determine the tintinnid species and their distributions in the Golden Horn Estuary and their ecological properties (temperature, salinity, dissolved oxygen, Secchi disk, pH, chlorophyll–a and nutrients), samples of the period before (2009–2010) and after (2013–2014) the Bosphorus water was connected to the estuary were evaluated. A total of 17 species were identified between 2009 and 2010, and 51 species were identified between 2013 and 2014. In both sampling periods, Tintinnopsis was recorded as the dominant genus with the highest number of species. When both periods are evaluated together, 14 species for Turkish coastal waters (Amphorellopsis acuta, Cymatocylis vanhoeffeni, Eutintinnus pectinis, Favella composita, Leprotintinnus cf. bottnicus, Metacylis pithos, Tintinnopsis rapa, T. cf. sacculus, T. cf. vasculum, Schmidingerella arcuata, Tintinnopis gracilis, T. lata, T. cf. rotundata, T. turbo) and 26 species for the Turkish Strait Systems are new records among 52 species have been reported from the region. Tintinnopsis was recorded as the genus with the highest number of species in both sampling periods. Favella ehrenbergii was determined to be the most common species in the Golden Horn Estuary. The highest number of tintinnid species and individuals were obtained from September–2014, and the least from January–2010. According to the data, an increase in the number of tintinnid species and a decrease in their abundance occurred in the period after the Bosphorus water was combined, also, the diversity of the tintinnid species was increased in the Golden Horn Estuary. In the study, fewer species numbers were reached in the stations located in the upper part of the Golden Horn estuary compared to the lower region. During the study, water temperature (5.4–26.9 °C), salinity (2.2–27.1‰), dissolved oxygen concentration (0.1–18.6 mg/L), pH (6.10–8.77), nitrite+nitrate–N (0.1–73.0 µM), ammonium–N (0.1–335.5µM), phosphate-P (0.0–17.0 µM) were measured and also Secchi disk depth (0.2–13.0 m) and chlorophyll–a values (0.1–112.00 µg/L) were determined. However, canonical correspondence analysis (CCA) was applied to the data and it was determined that temperature is the main factor affecting tintinnid species composition. Tintinnopsis beroidea was found to be closely related to NH4–N in both sampling periods. Accordingly, it is thought that T. beroidea can be used as a potential indicator species in determining the NH4–N status. According to the Wilcoxon test applied to the data obtained from both periods, when the results of two sampling periods were evaluated in all variables, except Secchi disk depth and phosphate-P, there were significant differences between them. In addition, according to the results of Shannon-Weaver diversity index, the environment was ecologically categorized for both periods and it was determined that the ecological situation of the region recovered after the tunnel water was connected. For this reason, it has been determined that tintinnids can also be used in the monitoring of rehabilitation studies.