Periphyton dry mass, ash content, and chlorophyll content on natural substrata in three water bodies of different trophy

Periphyton communities were studied on several dominating macrophytes, Phragmites australis, Potamogeton lucens, and Nuphar lutea, in three different types of lakes. In soft-water mesotrophic Lake Mały Borek and in shallow, eutrophic Lake Gardno samples were collected about once every two months from April to November 2009. In eutrophic Szczecin Lagoon (the estuary of the Oder River), samples were only collected once in July. The aim of this paper was to determine the dry mass, the ash content, and the chlorophyll-a content of periphyton on a natural substratum, in order to determine the mass, the inorganicorganic status of periphyton, and the auto-heterotrophic character of this complex. The analyzed periphytic communities exhibited low dry mass at the beginning of the growth season, which increased with colonization period on the aquatic vegetation. The highest (but still low) values were achieved in autumn, which persisted, with small loss, until spring of the subsequent year. The differences in dry mass between each type of lake were small, but in the strongly eutrophic Szczecin Lagoon this index was slightly higher than in the other two water bodies. The highest dry mass was noted for periphyton dominated by Cordylophora caspia colonies overgrowing common reeds and for periphyton on Potamogeton lucens in Szczecin Lagoon. In shallow water bodies, such as Lake Gardno and Szczecin Lagoon, wind causes strong resuspension of sediments. This can explain the relatively high level of inorganic matter in dry mass of the periphyton in both water bodies. However, the small ash content in periphyton in Mały Borek may result from the soft-water character of this lake. The hetero-autotrophic status of the periphytic community prevailed throughout the study period in Gardno and Mały Borek lakes. The auto-heterotrophic status of periphyton was noted only in short periods of time in each lake.