The ocean appears to have an aurora-like glow in this satellite image, but its source is far from cosmic.

The greenish glow swirling off the coastlines of Iceland and the Denmark Strait is actually caused by phytoplankton. With enough sunlight, planktonic algae can multiply by absorbing mineral nutrients and converting solar energy into organics.

While phytoplankton are tiny taken by themselves, together they can cause color shifts in ocean water, which in turn is detected by orbiting spacecraft.

This image was caught by the European Space Agency’s (ESA) Envisat satellite, which typically uses its Medium Resolution Imaging Spectrometer (MERIS) to make such observations.

-- SPACE.com Staff

Credit: ESA

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