In the ocean off the Amazon shelf, internal waves caused by tides move water layers up and down and mix them. Using an underwater glider and satellites, we found internal tides redistribute chlorophyll from the deep chlorophyll maximum upward to the surface and downward to depth. Turbulent chlorophyll fluxes supply about 38 % of surface chlorophyll, and total chlorophyll increases by 14–29 % during strong tides, potentially affecting the marine food web.