Seasonal variability of phytoplankton in the shallow waters of the southern Baltic Sea

The Baltic Sea is characterized by seasonal variation of phytoplankton structure. These organisms are particularly sensitive to changes in various environmental factors. Because of annually repeated changes, turnover of species composition, abundance and biomass of phytoplankton is observed. Spatial and temporal variability of individual phytoplankton groups is diversified in a district parts of the Baltic Sea. Therefore, of three different coastal areas were chosen: Ustka – estuary habitat, Poddąbie – sandy habitat and Rowy – rocky bottom habitat. The aim of this paper is to determine temporal and spatial structure of phytoplankton occurrence chosen coastal areas between November 2014 and September 2016. All three studies regions the same dominants, abundance and biomass were observed. Only in Ustka region increase of the diatoms was observed. Which could see the cause of river waters wave. Seasonal phytoplankton studies in three selected habitats revealed, that in those areas that abundance and biomass is similar (75%-80%). Based on this evaluation it is can be stated that conducting phytoplankton more frequently is more important than number of research stations.