A Preliminary Study on Using Rotifera Fauna to Determine The Trophic Level of The Büyükçekmece Reservoir (İstanbul, Turkey)

Abstract

In this study, the abundance of rotifera fauna, in the Buyukcekmece Reservoir (Istanbul) and some physicochemical features of the reservoir, were investigated between May 2009 and February 2010. In terms of physicochemical conditions, the trophic state of the reservoir was determined as eutrophic (CTSI= 57.8). A total of 33 rotifera species were identified. Keratella cochlearis represented 40.62% of the total annual rotifera present, and was predominant. It was followed by Polyarthra vulgaris (10.14%), Synchaeta oblonga (9.06%), Brachionus urceolaris (5.58%), Pompholyx sulcata (5.21%) and Epiphanes macroura (%4.86), respectively. The contribution of the other rotifer species to the annual presence of rotifera was determined as being 24.52%. The dominance of these species was attributed to the eutrophic state of the reservoir, because K. cochlearis, P. vulgaris, B. urceolaris and P. sulcata are known as eutrophication indicator species, due to their saprobic valences. Also, the trophic state of the reservoir was found to be eutrophic according to the QB/T index (= 3). According to the present data about rotifera species, and the abundance of them, the Buyukcekmece Reservoir was specified as eutrophic. However it is necessary to follow the conditions with periodic monitoring to observe the alterations in the Buyukcekmece Reservoir, in this respect the results of the present study would constitute an important baseline for subsequent studies.