Nilsun Demir

Evaluation of DNA Damage in Common Carp (Cyprinus carpio L.) by Comet Assay for Determination of Possible Pollution in Lake Mogan (Ankara)

Contamination of the aquatic environment with various concentrations of pollutants results in unexpected threats to humans and wildlife. The consequences of exposure and metabolism of pollutants/xenobiotics, especially carcinogens and mutagens, can be suitably assessed by investigating severe events, such as DNA damage; for example, DNA adducts and DNA strand breaks. One of the commonly used techniques to detect DNA damage in aquatic organisms is single-cell gel electrophoresis (comet assay). This study was carried out using Cyprinus carpio in order to identify the possible pollution in Lake Mogan, near Ankara, Turkey, where the citys sewer system and pesticides used in agriculture are believed to be the common causes of pollution. From the comet assay, the tail length (μm), tail intensity (%), and tail moment values of fish caught from Lake Mogan were found to be 31.10 ± 10.39, 7.77 ± 4.51, 1.50 ± 1.48, respectively, whereas for clean reference sites they were found to be 22.80 ± 1.08, 3.47 ± 1.59, 0.40 ± 0.51, respectively. The values are statistically different from each other (p < 0.0001, p < 0.0001, and p < 0.0013, respectively). These results indicate that Lake Mogan may be polluted with substances that have genotoxic effects and constitute an early warning for the lake system. Further detailed research is needed to establish the source of the pollution and the chemicals responsible.

Changes in the phytoplankton community of a coastal, hyposaline lake in western Anatolia, Turkey

The phytoplankton composition of coastal, hyposaline (≅12 g l−1) Lake Bafa in western Turkey, was investigated after the alteration of salinity levels in past decades. Lake Bafa, formerly a bay of the Aegean Sea, was separated from the sea as a result of alluvium deposits of the Meander River. After the construction of a sett for flood control in 1985, freshwater inflow was reduced and salinity increased, which caused some ecological changes. Phytoplankton samples were taken in August and November 2000, and February and May 2001, from the surface and at 5-m intervals in the water column at three stations. The phytoplankton community contained a mixture of freshwater and marine origin species. A total of 45 species from Bacillariophyceae, Chlorophyceae, Cyanophyceae, Chrysophyceae, and Dinophyceae were identified. Marineoriginated species such as Chaetoceros spp. (November and May), Thalassionema nitzschioides and Prorocentrum micans (August and November), and P. minimum (May) were dominant on the basis of numerical abundance. The occurrence of salinity-tolerant species such as T. nitzschioides, P. micans, and P. minimum has not been recorded in previous studies.

SAKARYABAŞI-BATI GÖLETİ’NDE TATLI SU KARİDESLERİNİN (PALAEMONETES TURCORUM HOLTHUIS, 1961) BAZI MORFOMETRİK ÖZELLİKLERİ

Bu calismada Sakarya Nehri’nin kaynaklarindan biri olan Bati Goletinde bulunan tatli su karidesi ( Palaemonetes turcorum Holthuis, 1961) populasyonunun bazi morfometrik ozellikleri arastirilmis ve uzunluk-agirlik iliskileri ortaya konmustur. Incelenen 207 adet bireyde esey orani (E:D) 1:0.3 olarak belirlenmistir. Ortalama toplam uzunluk ve karapaks uzunluklari sirasiyla; 2.95±0.84 cm ve 0.56±0.22 cm, erkeklerde 2.64±0.81 cm ve 0.60±0.45 cm, disilerde ise 3.64±0.32 cm ve 1.02±0.39 cm olarak saptanmistir. Ortalama karapaks uzunlugu disilerde 1.02±0.39 cm ve erkeklerde 0.60±0.45 cm olarak belirlenmistir. Incelenen tum bireyler arasinda vucut agirliginin en yuksek disilerde (1.10 g) oldugu tespit edilirken, boyca en uzun bireyin erkeklerde (4.50 cm) oldugu gozlenmistir. Karideslerin vucut agirligi ile toplam uzunluk ve karapaks uzunlugu arasindaki esitlikler ve kondisyon faktoru sirasiyla; W=0.0107xTL 2.8789 (R 2 =0.9121), W=0.8418xCL 2.1023 (R 2 =0.8863) ve KF=0.992±0.42 olarak hesaplanmistir.

Physokermes piceae (schrank) (yumrulu ladin koşnili) (hemiptera: coccidae)’nin biyolojik özellikleri

Bu arastirmada, 5 gunluk ot sazani (Ctenopharyngodon idella, Val.) larvalarinin stoklandigi bir toprak havuzda fitoplankton kompozisyonu ve biyokutlesinin degisimi 7 Temmuz – 2 Eylul 1998 tarihleri arasinda haftalik olarak incelenmistir. Havuzda Bacillariophyceae sinifindan 7, Chlorophyceae sinifindan 19, Chrysophyceae sinifindan 1, Cryptophyceae sinifindan 1, Cyanophyceae sinifindan 3, Dinophyceae sinifindan 4 ve Euglenophyceae sinifindan 2 tur olmak uzere toplam 37 tur teshis edilmistir. Fitoplankton biyokutlesi, arastirma suresince 2035 ± 345 ve 4456 ± 501 mg/m3 arasinda degismistir ve Chlorophyceae turleri baskin olarak belirlenmistir. Sonuclar, havuzun zooplankton kompozisyonu ve baliklarin mide icerigine gore tartisilmistir.