Coccolithophore bloom off Brittany, France

A bloom of what are probably coccolithophores - single-celled marine plants with white calcium carbonate shells - floats in the waters west of the English Channel in this Aqua MODIS image from June 15, 2004. The white shells, combined with the blue reflectance of the water, tint the water bright blue. The color could also be caused by other types of phytoplankton (also microscopic marine plants that grow near the surface of the ocean). When a large colony of the plants bloom, the chlorophyll colors the water green. In satellite imagery, the effect is often a bright blue-green patch in otherwise dark ocean water. More information about phytoplankton and coccolithophores can be found at the Earth Observatory.