Phytoplankton biomass and primary production in Delagoa Bight Mozambique: Application of remote sensing

Abstract

A non-linear model that uses satellite-derived chlorophyll to estimate water-column primary production was developed and tested using data from the Delagoa Bight, where the model results compared well with local estimates. The data were also used to assess variations in phytoplankton biomass and daily water-column primary production ( P ZT ; mg C m −2 day −1), in relation to physico-chemical variables. The distribution of phytoplankton biomass and primary production was partly influenced by gyre circulation and other water flow in the Bight, such as eddies, eastern Madagascar current and the Agulhas current. The locally-developed model could be applied throughout the region to estimate primary production. For low biomass (<0.3 mg m −3), the model tends to underestimate P ZT in a systematic way. However, such bias could be corrected using a 5th-order polynomial function. After this correction, the P ZT estimated using remotely-sensed chlorophyll a compared well with that calculated using in situ measurements. This outcome suggests that the model could be implemented for the estimation of mesoscale (regional) or large-scale (global) primary production.