The effect of anthropogenic change in the structure of diatoms and water quality of the Żołynianka and Jagielnia streams

The studies on bentic diatoms were conducted in 2009–2011 at eight samplings sites over the Żołynianka stream and its tributary, the Jagielnia. 427 diatom taxa were recorded in total. Achnanthidium minutissimum var. minutissimum, Aulacoseira ambigua, Fragilaria capucina var. capucina, Gomphonema parvlum, Navicula gregaria, Nitzschia palea and Planothidium lanceolatum were dominant taxa in both watercourses. Chemical analysis of water showed high chemical status of water at most of sampling sites. The results of diatomaceous analysis conducted with OMNIDIA software revealed moderate and poor condition of water. The best water quality was recorded in the Jagielnia stream (good or moderate status). The values of the analyzed indices showed the worst water quality on the Żołynianka at site four, showing bad ecological status. TDI index deviated the most from the other two indices (IPS and GDI), always indicating poorer water quality.