Pico‐, Nano‐, Microplankton Abundance and Primary Productivity in a Eutrophic Coastal Area of the Aegean Sea, Mediterranean

Primary productivity, pico-, nano-, microplankton and key environmental factors were studied in a eutrophic coastal area of the Aegean Sea during the winter - spring period. Primary productivity reached high values and showed similar trends of change to those of nanophytoplankton abundance. Nano- and microplankton cell densities showed high variability while picoplankton abundance was kept relatively stable. Diatoms dominated nanophytoplankton for most of the winter - spring period while a shift to dinoflagellates was initiated with the development of thermal stratification in late spring. Ciliates and heterotrophic dinoflagellates reached high densities in contrast to heterotrophic nanoflagellates. Our results emphasize the close relation between grazer densities and bacteria, cyanobacteria and nanoplanktic algal changes in this eutrophic coastal area of the Mediterranean.