The area of cyan colour is most likely caused by coccolithophores, which are microscopic single-celled plant-like organisms that live in large numbers throughout the upper layers of the ocean.
These phytoplankton produce calcium carbonate shells, which reflect a lot of light, giving their blooms a bright blue colour.
The green area off the Danish coast is caused by other phytoplankton species.
Phytoplankton play a key role in marine ecosystems as the basis of the food chain.
