An inherent optical property approach to the estimation of size-specific photosynthetic rates in eastern boundary upwelling zones from satellite ocean colour: An initial assessment

We derived size-specific photosynthetic rates for eastern boundary upwelling regions using satellite ocean colour, by a simple approach that links photosynthetic rate to phytoplankton size classes with the optical absorption of phytoplankton. Comparisons with a conventional chlorophyll-based photosynthetic algorithm and with in situ measurements showed good agreement with our approach (r2 = 0.728, p < 0.001). Preliminary results from satellite observations for upwelling regions suggest that production in nanophytoplankton-dominated communities may be larger than for those where microphytoplankton is predominant, due to the greater spatial extent of the former. However, photosynthetic rate per unit volume is shown to be larger for microphytoplankton-dominated communities.