Sünnet gölü (Bolu, Turkey) ekolojik değişimleri ve ostrakod (Crustacea) faunası

Environmental quality, habitat features and ostracod populations of LakeSünnet were monitored between May 2005 and September 2007. Biologic, physicochemicaland microbiological analyses were made synchronously both with sedimentand water sampling which were collected as a monthly. Water sample were alsocollected vertically at each meter from surface to bottom and littoral layer of the lake,as well. According to Unweighted Pair Group Mean Analyses (UPGMA) there arethree clustering groups. Spearman Correlation analyses indicated that there is apositive correlation between species number and electrical conductivity. Averagevalues were 0.1394 mg/l N for nitrogen and 0.0095 mg/l P for phosphate during twoyears. According to ANOVA, there were no remarkable differences in the measuredvariables except turbidity between littoral stations.At the end of the study, nine living Ostracoda species, which 6 arecharacterized as cosmopolitan were recorded (Candona neglecta, Ilyocypris bradyi,Ilyocypris getica, Ilyocypris inermis, Limnocythere inopinata, Physocypriakraepelini, Stenocypria fischeri, Pseudocandona cf. eremita and Pseudocandonaalbicans) in the Lake. During the study, species and individual number of Ostracodawas very low comparing to another lakes in Bolu. The ratio of pseudorichness(noncosmopolitan/cosmopolitan) is about 0.33. Accordingly, cosmopolitan speciesseem to be dominant. Lake water quality display a dynamic behaviour due to largechanges in the water levels from 14 to 8 meters. Finding, therefore, suggest the ideathat Lake Sünnet show shows mesothrophic characteristics. These physical changesare not only alter ecological charateristics of the lake but also biological diversity.Indeed, this is probable that cosmopolitans tolerate them more than other species.