Cold water rich in nutrients may be upwelled to the surface, supporting a phytoplankton bloom. Coastal upwelling is likely to occur when there is a consistent wind blowing along the shore such that it drives a current that flows away from the shore consistent with the Coriolis effect. These upwelling events can be detected by satellite due to the relatively decreased temperatures and increased chlorophyll concentrations that characterize the affected surface waters.

The image at right shows upwelling events near the Hawaiian Islands.