Seasonal impact of the microzooplankton on pico-and nanoplankton growth rates in the northwest Mediterranean Sea

The effect of protozoan presence on pico-and nanoplankton growth rates was studied during a whole seasonal cycle.together with several other environmental factors (such as microphytoplankton abundance, temperature, salinity, solar irradiance and nutrients).Pico-and nanoplankton growth rates were enhanced in the presence of protozoa inside a dialysis bag and reached values as high as 0.08 to 0.2 h-1 At in situ concentrations (10 6 flagellates 1-1 and 10 3 ciliates 1-1 ), protozoa, through their excretory activity, played an important role in phytoplankton growth.However, other environmental factors, such as allochthonous nutrients and temperature.also have an effect on these growth rates.