File:Phytoplankton Bloom off South America (MODIS 2021-11-03).jpg

English: As autumn brings chilly weather, shortening sunlight, and color changes to the landscape of the northern hemisphere, the southern hemisphere moves into springtime. South of the equator the months from September through December bring lengthening daylight and warming air and sea surface temperatures that also bring color changes, such as this jewel-toned bloom spreading across the South Atlantic Ocean.

On November 1, 2021, swirling clouds parted to reveal swirls of dull blues and greens gracing the ocean east of southern South America and southeast of the Falkland Islands. The Moderate Resolution Imaging Spectroradiometer (MODIS) on board NASA’s Terra satellite acquired a true-color image of the scene that same day. It appears that southern-most clouds obscure a swath of brighter blue bloom.

Phytoplankton are tiny, plant-like organisms that float near the ocean surface and turn sunlight and carbon dioxide into sugars and oxygen. In turn, they become food for the grazing zooplankton, shellfish, and finfish of the sea. They also play an important role in the global carbon cycle, taking carbon dioxide out of the atmosphere and sinking it to the bottom of the ocean. Phytoplankton live in these waters year-round, but not in large enough colonies to be viewed from space. When conditions are right, they can burst into explosive reproduction to create large floating blooms which can cover many miles of the ocean’s surface.