the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) Project. SeaWiFS provides quantitative data on global ocean bio-optical properties. Subtle changes in ocean color represent various types and quantities of marine phytoplankton. The ocean color in the visible light region (wavelengths of 400-700 nm) varies with the concentration of chlorophyll and other plant pigments present in the water. The more phytoplankton present, the greater the concentration of plant pigments and the greener the water. These microscopic marine plants, such as algae and some bacteria, exist at the lowest levels of the food chain and use sunlight or chemical energy, rather than organic material, as sources of energy. It is thought that marine plants remove carbon from the atmosphere at a rate equivalent to terrestrial plants, but knowledge of interannual variability is needed the SeaWiFS instrument