Phytoplankton composition and biomass of the northern Adriatic lagoon of Stella Maris, Croatia

This study provides information on the seasonality of phytoplankton abundance, biomass expressed as cell volume and cell carbon, as well as species composition, in the small, shallow, brackish northern-Adriatic lagoon of Stella Maris near Umag (Croatia). The lagoon is permanently connected with the adjacent sea. Wide seasonal temperature and salinity excursions regulate phytoplankton assemblages. Unlike other Adriatic lagoons, the lagoon of Stella Maris showed moderate phytoplankton abundance, cell volume and carbon content and a high number of species. The specific diatom volumes from the Stella Maris lagoon were higher than those found in other Adriatic lagoons, whereas the specific volumes of dinoflagellates were in the same range. Diatoms represented 55% of all the species found, but there was a considerable contribution of nanoplankton and dinoflagellates in the annual outbursts. Keywords: phytoplankton, taxonomy, cell volume, cell carbon, coastal lagoon, Adriatic Sea