Life's Signature Colors, Captured by Satellite

Think of Earth's great life forms and images of cheetahs, whales and dinosaurs come to mind. Towering redwood trees, majestic plains of grasses on Asian steppes: Earth's living glow fills the eye with diversity, resilience, and endless Darwinian invention.
But arguably one of the most essential populations on Earth would have no chance if pitted against others in a contest based on looks alone. More than any other kind of life, the Earth lives and breathes because of the profound success of lowly phytoplankton.
Phytoplankton is a broad, catch-all name for a wide category of simple organisms living primarily in the world's oceans. Floating in vast fields of billions of tiny individual plants, these essential life forms make up a colossal proportion of the Earth's total biomass. It's also vital to the overall web of life on Earth. Phytoplankton serves not only as the base of the aquatic food chain, but also as the principal source of atmospheric oxygen worldwide.
As global climate continues to change, a complex set of forces begins to push and pull on the ability of phytoplankton populations to thrive. Changing global ocean temperatures have enormous influences, as does changing ocean chemistry. But while this may present itself as a subject of purely academic interest, phytoplankton populations may present one of the most vital bellwethers for practical changes beginning to take hold of a planet in transition.
NASA's SeaWiFS spacecraft is one of the most powerful tools in keeping up with these trends. A small, low cost vehicle and instrument package, SeaWiFS monitors the colors of the world everyday. As a proxy for bioproductivity, color is the key to understanding how these oceanic lifeforms are faring...and changing.