EVALUATION OF THE WATER TROPHIC STATE OF WAPIENICA DAM RESERVOIR

In this publication the trophy level of Wapienica dam reservoir, based on the composition species of planktonic algae and their biomass, and concentrations of chlorophyll a, was defined. The research was conducted during the vegetative season in 2013 year; the samples were taken from two research points (W1 – the part of river Wapienica inflow to reservoir and W2 – the part of the reservoir dam) by using bathometer. The whole biomass of planktonic algae and concentration of chlorophyll a from two research areas were low and it allowed to classify water of this reservoir to oligo-/ mesotrophic. Only in the part of the reservoir dam, in summer season, an increased trophy level was observed (Heinonen 1980). A similar trophic character (oligo-/ mesotrophic) of the water reservoir was also indicated by algae species: <i>Achnanthes lanceolata</i> (Bréb.) Grun. in Cl. and Grun., <i>Chrysoccoccus minutus</i> (Fritsch) Nygaard. For a temporary increase of the trophy level, the diatom <i>Nitzschia acicularis</i> (Kütz.) W. Sm. could indicate, because it is a typical species in poorly eutrophic water. The green algae (<i>Pediastrum</i> and <i>Coelastrum</i>, which were observed in summer season) could also indicate for a rise of the trophic state, because they are typical for eutrophic water