NASA captured the Black Sea turning brilliant turquoise from space
NASA's PACE satellite captured the Black Sea turning vivid turquoise due to massive blooms of coccolithophores, microscopic phytoplankton with calcium carbonate shells. This seasonal phenomenon, visible from space, occurs in late spring and early summer, contrasting with the darker appearance caused by diatoms at other times.
Why it matters
These blooms are crucial for monitoring marine ecosystems and play a significant role in Earth's carbon cycle by absorbing atmospheric carbon, offering insights into climate change and ocean health.
The Black Sea, which lies between Europe and Asia and connects to the Mediterranean through a series of waterways, is known for its dark waters. But every spring and summer, it undergoes a remarkable transformation, with large areas turning a vivid turquoise. On June 22, 2026, NASA's PACE (Plankton, Aerosol, Cloud, ocean Ecosystem) satellite captured this colorful seasonal display using its OCI (Ocean Color Instrument).
Scientists believe the striking turquoise color comes from blooms of coccolithophores, microscopic phytoplankton coated in calcium carbonate plates. When these organisms multiply in enormous numbers during late spring and early summer, their reflective shells scatter sunlight and give the ocean a milky blue appearance that is visible even from space.
At other times of the year, different microscopic algae called diatoms become more abundant. Unlike coccolithophores, diatoms have silica shells and generally make the Black Sea appear darker instead of brighter.
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