The Terra satellite is designed to study our planet from space, examining the environment over large scales and in high resolution. While passing over south Africa it took this seemingly normal — if still very beautiful — image:
I rotated it, so north is to the left. You can see land to the left, the southernmost tip of Africa, called Cape Agulhas. To the top is the Indian ocean, with the Atlantic to the right. A weather system is forming there, and all looks as it should… until your gaze settles all the way to the right (south). Wait… what’s the blue swirly thing?
Holy otology! Is that a giant ear?
Nope. It’s an eddy, a vortex, in the ocean, probably spun off the ocean current that flows around the southern horn of Africa. These eddies can dredge up material from deeper waters, including nutrients. Phytoplankton in the water feeds of those nutrients, and bang! Plankton bloom.
The plankton flows along with the water, coloring it blue, making it stand out eerily against the water. As I pointed out ...
