The role of the Leeuwin Current and mixed layer depth on the autumn phytoplankton bloom off Ningaloo Reef, Western Australia

► We investigate the drivers of the autumn phytoplankton bloom off Western Australia. ► Deepening of the mixed layer induced an increase in nutrient concentration. ► The key mechanism driving the autumn bloom is the deepening of the mixed layer. ► We suggest that irradiance has less impact on net growth than grazing.