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

Abstract

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.

Field data analysis and application of a complex water column biogeochemical model in different areas of a semi-enclosed basin: towards the development of an ecosystem management tool

“…A modeling experiment in this part showed that under nutrient enrichment diatoms contribute %2/3 of the total phytoplankton biomass followed by picoplankton and flagellates. This is in accordance with observations in the semi-enclosed gulf of Thermaikos where diatoms formed most of the reported algal blooms (Mihalatou & Moustaka-Gouni, 2002).…”

“…14) are very close to the field measured range of 5-23 and 0.2-4.5 lg/l/d, respectively (Pancucci-Papadopoulou & Christaki, 2000) with higher rates during winter to spring for phytoplankton and middle of spring for bacteria at both areas. Highest primary production rates in January were also recorded in Thermaikos (Mihalatou & Moustaka-Gouni, 2002). At the more eutrophic internal station throughout the year the primary producers exhibit much higher rates compared to bacteria without any significant variability with depth.…”

“…An important common characteristic is the prolonged thermocline decoupling the near bottom layer from the upper euphotic zone. Unlike the two other major semi-enclosed gulfs in Greece (Saronikos and Thermaikos), Pagasitikos is considerably less eutrophic with significantly lower nutrient concentrations (Friligos, 1982;Mihalatou & Moustaka-Gouni, 2002). Another significant difference is that although most closed and semi-closed systems are phosphate limited, Pagasitikos exhibits significant periods of nitrogen limitation.…”

Airborne microeukaryote colonists in experimental water containers: diversity, succession, life histories and established food webs

“…Field and experimental procedures. Marine and freshwater plankton samples from Thermaikos Bay and from the university pool, respectively, were collected weekly from surface water in accordance with Mihalatou & Moustaka-Gouni (2002) Airborne particles were recovered during the same period using an air sampler which collected air at a rate of 16 l min -1 . The air was drawn into a conical flask containing 300 ml of sterile distilled water, and airborne particles were trapped and collected in the water.…”

Seasonal variations of microphytoplankton assemblages and environmental variables in the coastal zone of Bozcaada Island in the Aegean Sea (NE Mediterranean Sea)

“…At the same time, relatively few studies on primary productivity and pico-, nano-, and microplankton abundance have been published (Kormas et al 1998;Robinson 2000;Mihalatou and Moustaka-Gouni 2002). The population structure and dynamics are greatly influenced by the different hydrographic conditions prevailing in the northern and southern Aegean Sea due to the influence of Black Sea and Levantine Sea waters, respectively.…”