🌊🌱 28 years of a living ocean, month by month

This is ocean surface chlorophyll from September 1997 to December 2025, seen from space. Chlorophyll is the pigment of phytoplankton: microscopic algae responsible for roughly half of the photosynthesis on the planet and the base of almost all marine life.

What to look for:

🔵 The great blue deserts in the middle of the oceans. These are the subtropical gyres, crystal-clear, nutrient-poor waters where very little grows.

🟢 The green and yellow bands hugging the western coasts of the continents. This is upwelling: winds push surface water offshore and cold, nutrient-rich water rises from below. The Canary Islands sit next to one of the four great upwelling systems of the world, off northwest Africa.

🌸 The North Atlantic spring bloom, lighting up every year around April and May and spreading northward. Six months later, the same happens in the Southern Hemisphere.

⚫ Black is not lifeless ocean: it means no data, due to sea ice, persistent clouds or the polar night, when satellites cannot see the colour of the sea.

The colour scale is logarithmic: each step means ten times more chlorophyll. Between the centre of a gyre and a coastal upwelling there is more than a thousandfold difference.

The map uses the Spilhaus projection, which shows the world ocean as a single continuous body of water, with Antarctica at the centre.

Data: ESA Climate Change Initiative, Ocean Colour v6.0