NASA's PACE satellite captured the Black Sea turning turquoise on June 22, 2026, due to a massive bloom of coccolithophores. These microscopic phytoplankton have calcium carbonate shells that reflect sunlight, making the water visible from space. The bloom also stretched into the Bosphorus, as photographed by astronauts on the ISS. Coccolithophores play a key role in Earth's carbon cycle. They absorb carbon from the atmosphere and water as they grow. When they die, some of that carbon sinks to the seafloor and stays stored for long periods. This natural process helps transfer carbon from the surface into long-term storage, which is relevant to understanding marine carbon sinks. Satellite monitoring of these blooms gives scientists a way to track marine ecosystems and carbon cycling in areas where water sampling is difficult. The data helps improve models of how ocean biology interacts with the global carbon budget.
