PRELIMINARY ECOLOGICAL STATUS ASSESSMENT OF THE GROŠNICA RIVER BASED ON PHYTOBENTHOS

Abstract

The research on the Grošnica River was conducted to obtain data on benthic algae diversity and provide a preliminary assessment of water quality due to the absence of prior studies. Benthic algae sampling and analysis were carried out in May 2022. In five selected localities, a total of 28 taxa of benthic algae were detected: Cyanobacteria (3), Rhodophyta (1), Chlorophyta (2), Ochrophyta (Xanthophyceae) (1), and Bacillariophyta (21). A preliminary assessment of the ecological status was carried out according to the guidelines of the Water Framework Directive and national legislation, using the IPS diatom index. In addition, literature data on the indicator properties of observed macroalgae were examined. Based on the obtained values at localities L1, L2, L3 (upper course), a good ecological status was determined, while at locality L4 (middle course) a moderate ecological status was determined, and in locality L5 (lower course) a good ecological potential of theGrošnica river was determined. The occurrence of massive growth of macroalgae Cladophora glomerata and Vaucheria sp. in the middle (L4) and especially in the lower reaches of the river (L5)indicates an increased amount of nutrients and deterioration of water quality.