ASSESSMENT OF OCCURRENCE MICROPHYTES AND TROPHIC STATUS OF A SMALL WATER BODY IN THE WIELKOPOLSKA REGION (WESTERN POLAND)
The paper presents results of studies on microphytes found in a small and shallow water body located in the village of Drwesa in the Dopiewo community (near Poznan). The aim of investigations conducted in 2011 was to determine the taxonomic composition, abundance and biomass of microphytes, the amount of seston and selected environmental factors. The greatest species richness was observed for green algae and diatoms, while the total abundance of microphytes was usually moderate. Flagellates predominated, mainly chrysophytes, dinoflagellates and cryptophytes. Maximum abundance were recorded in spring and their frequent dips in summer and autumn. Microphyte biomass estimated by the concentration of chlorophyll a was generally high and significantly correlated with the amount of seston. Indicator species comprised 35% of the microphytes taxa and eutrophic indicator species predominat. The structure of microphytes indicated mesotrophy of the water body, while the concentrations of chlorophyll a and seston showed eutrophy.