Physical and biological controls on the summer chlorophyll bloom to the east of Vietnam

The contributions of physical and biological processes to the chlorophyll-a (Chl-a) bloom to the east of Vietnam in summer are examined. The offshore jet redistributes Chl-a concentration by transporting high Chl-waters from the continental margin to the east of Vietnam. The jet also contributes to high concentrations of nutrients and zooplankton biomass that lead to a dynamic balance between increased nutrients and grazing pressure for phytoplankton growth. As a consequence, the net biological processes reduce the Chl-a concentrations in the broader offshore region, but they also maintain the filaments with higher Chl-a stretching away from the coast due to the reduced grazing pressure.