Parameters of light-dependent photosynthesis for phytoplankton size fractions in temperate estuarine and coastal environments

Photosynthetic parameters for netplankton (>22 m) and nanoplankton (<22 m) varied over similar ranges but exhibited different seasonal and geographic patterns of variation. Nanoplankton a was relatively constant (0.06 mg C [mg Chl · h]^-1 [E m^-2 s^-1]^-1), but P_m^B(mg C [mg Chl · d]^-1) was an exponential function of temperature independent of nutrient concentration and vertical stability in the euphotic zone. The temperature function gives a P_m^Bof 24 at 25°C for nanoplankton growing in an estuarine environment characterized by high nutrient concentrations and a shallow, stratified euphotic zone. Variations in netplankton a and P_m^Bwere less predictable and were not correlated with temperature, nutrients or vertical stability. Chain forming diatoms with small cells were able to achieve high (0.10 to 0.15) and P_m^B(20 to 24) that were 3 to 5 times higher than large-celled diatoms and dinoflagellates were able to achieve.