SeaWiFS was designed to measure ocean color. This seemingly narrow measurement captures the fundamental biological activity at the ocean surface, the blooming and die-off of the phytoplankton that form the center of the oceanic food web. Its abundance is a direct indicator of the seas’ ability to support life. It also plays a central role in the oceans’ carbon uptake. SeaWiFS also was used to offer real-time monitoring of red tides and other harmful algae, which can bloom in polluted waters and be deadly to fish and oysters.
Modifications made to SeaWiFS before launch also allowed it to make a similar kind of measurement of plant color on land. This ability to see all of the planet’s plant life with a single, well-calibrated instrument produced a first-of-its-kind snapshot of the Earth’s biosphere in 1998, similar to the image above.