Diatoms diversity and ecological status of the Đetinja River (Serbia)

Abstract

The Đetinja River is located in western Serbia and it was dammed for creating an artificial Lake Vrutci. Epilithic samples were collected during 11 season (September, October and December 2014, March, April, May, June, July, August, September and October 2015) and were scraped from the stones by brush. Permanent slides were observed by Zeiss AxioImagerM.1 microscope with DIC optics and AxioVision 4.8 software. The relative abundance of diatoms were estimated by counting 400 valves of each taxa present at every permanent slide. The biological assessment of water quality was performed using diatom indices calculating by OMNIDIA 5.3 software. Total of 113 diatom taxa have been recorded in the studied samples. Achnanthidum minutissimum was abundantly developing in mass and predominating over the other diatoms in almost all season. Next to A. minutissimum Amphora inariensis, A. pediculus, Cocconeis placentula var. lineata, Gomphonema olivaceum, Nitzsschia amphibia and N. fonticola were dominant or subdominant in the community. The results of a diatom indices analysis show the good to very good ecological status of the Đetinja River in the investigated period. Organic pollution was absence as opposed to anthropogenic eutrophication. In almost all season anthropogenic eutrophication was low except in March where anthropogenic eutrophication was moderate. In March Gomphonema olivaceum was dominant taxa in the community. G. olivaceum is β-mesosaprobous, eutraphentic species. The Đetinja River was characterized by high species diversity and good to very good ecological status which matches with the literature data, rivers and streams with low level of pollution are characterized by high species richness.