File:Phytoplankton bloom in the English Channel.jpg

English: On 23 June one of the Copernicus Sentinel-2 satellites acquired this stunning view of a phytoplankton bloom in the English Channel. Phytoplankton are microscopic plant-like organisms that grow, multiply, and drift in the sunlit surface waters of most bodies of water on Earth. Phytoplankton represent the base of the ocean’s food chain: most species contain chlorophyll and produce energy via photosynthesis. When present in high concentrations in the water, the chlorophyll in their bodies gives the water a greenish colour. Other phytoplankton species produce secretions composed of calcium carbonate. In high concentrations, these secretions can give a the water a light turquoise colour. When the conditions are right, the phytoplankton population can grow explosively – a phenomenon that is known as a bloom. Blooms are indicators of the health of a marine ecosystem, and therefore, their monitoring is a key component of effective management of coastal and oceanic resources. The Copernicus Sentinel-2 and Sentinel-3 missions provide continuous, high frequency water quality monitoring of coastal waters.