Off the coast of Patagonia in late December 2010 (but not posted until January 1, 2011, if you were wishing to penalize me) a phytoplankton bloom erupted, coloring the Atlantic waters in various shades of teal. Colliding currents stir up the plankton in eddies and whorls, clearly visible in this photo taken by NASA's Aqua Earth-observing satellite.
Image credit: Norman Kuring, NASA’s Ocean Color websiteOriginal imageOriginal blog post