- Size classes of phytoplankton
Picoplankton: 0.2-2 µm
Nanoplankton: 2-20 µm
Microplankton: 20-200 µm
Phytoplankton size ranges from 0.4 µm to the millimeter scale. Picoplankton (0.2-2.0 µm) was considered only bacteria until the discovery of the unicellular cyanobacteria Synechococcus (ca. 1-1.5 µm; 1979) and Prochlorococcus (0.4 µm; 1989)
-
Surface
area-to-Volume Ratio: decreases expo-nentially
with cell size; small cells have a high ration, large cells a low ratio
- Algal growth is dependent on material exchange at the cell surface (CO2, nutrients)
- Smaller cells with higher SA/V ratio are more efficient in nutrient uptake
-
Algal
growth rate increases with SA/V ratio
-
Small
phytoplankton dominates in nutrient-poor waters (where total phytoplankton
biomass is also low)
