File:Phytoplankton bloom in the Black Sea.jpg

English: Most summers, jewel-toned hues appear in the Black Sea. The turquoise swirls are not the brushstrokes of a painting, they indicate the presence of phytoplankton, which trace the flow of water currents and eddies. On 10 May 2020, the Copernicus Sentinel-3B satellite captured an ongoing phytoplankton bloom in the Black Sea. Phytoplankton are floating, microscopic organisms that make their own food through photosynthesis and also from absorbing dissolved nutrients in the sea water. Here, ample water flow from rivers, such as the Danube river, carry nutrients to the Black Sea. In general, phytoplankton support fish, shellfish, and other marine organisms as they are at the base of the food chain, one reason being, the waste product of photosynthesis is oxygen But large, frequent blooms can lead to eutrophication—the loss of oxygen from the water—and this ends up suffocating marine life. Measuring ocean colour, the Copernicus Sentinel-3 satellites allow us to capture, monitor and better understand marine life, their biological constituents and their activity.