File:Phytoplankton Bloom in Southern Atlantic (MODIS 2020-01-02).jpg

English: The South Atlantic Ocean was filled with brilliant blues and glorious greens on December 28, 2019, when the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite acquired this true-color image of the colored-water scene.

The intense and widespread colors are created by densely concentrated colonies of phytoplankton floating on the surface of the ocean. These microscopic plant-like organisms thrive in the cool, nutrient-rich waters in this location off the coast of Argentina. Here, the Malvinas (Falkland) Current sweeps north from the frigid Southern Ocean along the shallow continental shelf. The interaction of the current with the edge of the shelf pulls nutrients from the shelf floor to the surface, and this provides the “fertilizer” needed to drive plant growth. Summertime blooms are often especially intense, as the warmer waters and longer sunshine also spur growth and reproduction of these amazing organisms.

Because phytoplankton sit at the base of the marine food chain, the parts of the ocean that support large blooms tend to have a large and diverse population of fish and other animals. Phytoplankton also play an important role in the global carbon cycle. Like all plants, phytoplankton soak up carbon dioxide, providing a crucial sink for that greenhouse gas.