What shimmers so turquoise and bluish in the water of the North Sea are billions and billions of microscopic algae – from the perspective of a satellite.
When these algae multiply explosively, they form huge colorful carpets that can even be seen from space. Such algal or phytoplankton blooms typically occur in the North Sea in late spring and early summer, when melting snow, spring rains and high winds carry nutrients out to sea, “feeding” the tiny, plant-like algae. Sun and warm sea temperatures also favored this blue bloom between Scotland and Norway.
Phytoplankton are to the ocean what plants are to the land: they carry out photosynthesis and thus become the energy-rich snack that forms the basis of all food webs in the sea. During the course of their photosynthesis, the microalgae and cyanobacteria also absorb carbon dioxide from the atmosphere and produce oxygen. In fact, at least every second molecule of oxygen we breathe comes from the ocean.
The blue bloom in the North Sea is likely made up in part of diatoms, a type of phytoplankton with silica shells. They typically color the water green. Together with plenty of calcareous algae with calcium carbonate shells, which provide a milky blue colour, they create a dazzling play of colors here.