Abstract

Using the method of process-oriented hydrodynamic modelling, this study explores wind-driven upwelling features around atoll reefs. The three-dimensional physical model is coupled to a biological model to simulate phytoplankton blooms initiated by the upwelling. Findings demonstrate that wind forcing can create a zone of nutrient upwelling near atolls reefs fuelling significant subsurface phytoplankton blooms. Here we show that both lowering surface salinity due to enhanced precipitation, and submergence of the atoll reef due to sea level rise and enhanced erosion lead to a significant reduction of phytoplankton productivity. We expect that this climate-change related reduction in phytoplankton production around atoll reefs will cause severe disruptions to the functioning of marine ecosystems in tropical oceans.