Phytoplankton bloom colours Romania’s Black Sea coast
Phytoplankton are microscopic marine organisms which form the base of the marine food web and multiply rapidly when light and nutrient conditions are favourable.
In early May 2026, a phytoplankton bloom developed in the western Black Sea off the coast of Romania, remaining visible through late May.
This natural-colour image, acquired by one of the Copernicus Sentinel-2 satellites on 26 May 2026, shows the Romanian coast around the city of Constanța and the Danube Delta. Offshore, the bloom appears as extensive turquoise and milky-blue swirls against darker open water, reflecting surface patterns shaped by local currents.
Copernicus Sentinel-2 and Copernicus Sentinel-3 data help track the extent and development of phytoplankton blooms, supporting water-quality monitoring, coastal management, and assessments of potential impacts on marine ecosystems, fisheries, and tourism.
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