Fitobentos in kakovost vode v mrtvicah reke Mure

The purpose of our research was to determine species composition and abundance of phytobenthos in the selected Mura River's oxbows, as well as to determine water quality on the basis of indicator phytobenthos species. Altogether, 147 taxa from five algal classes were determined. According to the number of identified taxa, diatoms with 117 (80 %) taxa prevailed, followed by Chlorophyceae with 11 (7 %), Cyanobacteria with 10 (7 %), Xanthophyceae with seven (5 %) and Euglenophyceae with two (1 %) taxa. The most abundant genera were Navicula and Nitzschia. In the oxbow Zaton I, 37 algal taxa were identified, in the oxbow Zaton II 75, and in the oxbow Mali Bakovci 107. In the selected Mura oxbows, altogether 25 taxa for the first time identified in the territory of Slovenia were determined. 19 taxa new to Slovenia belong to the class of diatoms, Borzia curta and Woronichinia robusta to the class Cyanobacteria, Bumilleria klebsiana and B. spirotaenia to the class Xanthophyceae, Characium ensiforme and Microspora abbreviata to the class Chlorophycea. According to the results of the Saprobic Index, we can classify the Mura oxbows at sampling site Zaton I into II-III quality class, which means a critical load of the water body, and at sampling site Zaton II and Mali Bakovci into II quality class, which means a moderately polluted water body.