I recently came across a very good article describing what Ocean Color measurements mean, what they are used for, and how future NASA satellites will extend the reach of global ocean color observation and research.
Ocean color measurement enables us to infer the biological and biogeochemical composition of the ocean. The first proof-of-concept ocean color mission was the Coastal Zone Color Scanner (CZCS), launched in 1978. This was followed later by many ocean color science missions, some of which are: Sea-viewing Wide Field-of-view Sensor (SeaWiFS), Moderate Resolution Imaging Spectroradiometer (MODIS) onboard Aqua and Terra satellites, and Visible Infrared Imager Radiometer Suite (VIIRS) onboard Suomi NPP. Two upcoming ocean color missions are the Pre-Aerosol, Clouds, and ocean Ecosystem (PACE) slated to be launched in 2022, and the Geostationary Coastal and Air Pollution Events (GEO-CAPE), which is still in development.
Read more here: