Full Length Research Paper

Comparative performance of diatom indices in aquatic pollution assessment

Hasan Kalyoncu¹, Nazire Lerzan Çicek², Cengiz Akkoz³ and Bülent Yorulmaz*

¹Süleyman Demirel University, Science and Art Faculty, Department of Biology, Isparta, Turkey.

²Süleyman Demirel University, Egirdir Fisheries Faculty, Isparta, Turkey.

³Selçuk University, Science and Art Faculty, Department of Biology, Konya, Turkey.

⁴Muğla University, Science and Art Faculty, Department of Biology, Muğla, Turkey.

*Corresponding author. E-mail: yorulmaz@mu.edu.tr.

Accepted 7 September, 2009

   Abstract

The use of epilithic diatoms as indicators of river water quality was evaluated in two streams of south Turkey.  Diatoms as well as physical and chemical variables were sampled monthly between May, 2002 and April 2003 at six sites that can represent the streams. A total of 110 diatom taxa belonging to 32 genera were found. The most tolerant taxa to organic pollution were Nitzschia palea (Kützing) W. Smith., Craticula accomoda (Hustedt) D.G. Mann., Gomphonema parvulum (Kützing) Kützing, Navicula atomus (Kützing) Grunow, Navicula cryptocephala Kützing. These species were dominant at the organically polluted stations. The performance of three types of benthic diatom index was compared (Swiss Diatom Index (DI-CH), Trophic Index (TI) and Saprobic Index (SI)). The indices were significantly correlated with dissolved oxygen, chloride, biological oxygen demand (BOD₅), and concentrations of nutrients (NO₃-N, NO₂-N, NH₄-N, and PO₄-P). DI-CH, TI and SI had high correlations with the physicochemical variables but DI-CH and TI were more reliable than the SI. We concluded that in these rivers, DI-CH and TI could be more useful than SI. Based on the significant correlation with nutrients and organic pollution variables this study suggests that SI, TI and DI-CH are integrating the effects of organic pollution.

Key words: Diatom indices, pollution assessment, Turkey.