The Black Sea, usually known for its dark waters, transformed into a stunning turquoise expanse this spring and summer due to abundant phytoplankton blooms captured from space by NASA’s PACE satellite.
- Turquoise color caused by coccolithophore phytoplankton blooms
- International Space Station images complement satellite observations
- Blooms play a role in the ocean’s carbon cycle by storing carbon in seafloor sediments
What happened
During the spring and summer months of 2026, the Black Sea and adjacent waterways, including the Bosphorus Strait near Istanbul, exhibited a striking turquoise hue. This milky-blue tint was caused by a bloom of coccolithophores, a type of phytoplankton covered in calcium carbonate plates, which become visible from space when they bloom in large numbers.
NASA’s PACE satellite, equipped with the Ocean Color Instrument, captured detailed images of the waters on June 22, 2026. An astronaut aboard the International Space Station also photographed the Bosphorus area on May 27, offering a complementary perspective on the bloom’s extent and dynamics as it moved along local currents.
Why it feels good
Seeing the vibrant turquoise waters from space offers a rare natural spectacle and highlights the incredible diversity and activity within aquatic ecosystems. These phytoplankton blooms not only add color but also signal a healthy surge in microscopic marine life, which forms the base of the ocean’s food web.
Beyond their visual impact, coccolithophore blooms have an important environmental role. When these organisms die, some of the carbon they absorb from the atmosphere sinks to the ocean floor, helping to regulate global carbon levels and contributing to long-term carbon storage in marine sediments.
What to enjoy or watch next
As the seasons progress, the phytoplankton populations in the Black Sea will shift, with other microscopic algae like diatoms becoming more dominant during parts of the year, typically darkening the water. Watching these natural cycles of bloom and color change through NASA’s ongoing satellite and astronaut photography programs offers an engaging glimpse into Earth’s living waters.
For more breathtaking views and updates on Earth’s changing environments, keep an eye on NASA’s Earth Observatory and follow imagery from both satellite sensors and the International Space Station crew, who capture unique photos that help scientists and the public appreciate our planet’s dynamic ecosystems.