An investigation on the benthic diatoms from the Akarçay stream (Afyonkarahisar) and their use for water quality assessment

Epipelic diatoms and some physico-chemical features of Akarçay streams were studied in the samples collected montly from four sampling-stations during March-December 2008. Bentich diatoms were used for water quality assessment of the Akarçay streams.A total of 128 taxa of benthic diatom communities were determined. In the upstream Cocconeis placentula, Cyclotella meneghiniana, Encyonema minutum Sellaphora pupula, Nitzschia tubicola, Cymatopleura solea, Amphora veneta, Amphora pediculus, Ulnaria ulna, Gomphonema parvulum, Gomphonema angustatum and Navicula cryptocephala were dominant species in the benthic diatom communities. In downstream Nitzschia palea was dominant species in the benthic diatom communities. Diatom indices showed a significant positive correlation with TDS, NH4-N, NO2-N, PO4-P, BOD5 , COD and, were correlated negatively with DO.According to results of diatom index and physico-chemical analysis, the upstream was determined to be moderately polluted and the downstream was determined to be excessively polluted.Key words: Benthic diatom, diatom indices, physico-chemical features, Akarçay