This globe shows the mean surface chlorophyll-a from 1997 to 2025, measured by satellites. Chlorophyll tracks phytoplankton, the microscopic algae that carry out roughly half of the photosynthesis on Earth.

The surface is deformed to make the pattern easier to read: waters richer than the global average rise outward, poorer waters sink inward. It is a visual device, not real topography.

What stands out:

🔵 The sunken blue basins in the middle of every ocean. These are the subtropical gyres, the largest biological deserts on the planet.

🟢 The raised green and yellow rims along the coasts, especially the western margins of the continents, where upwelling brings nutrient-rich deep water to the surface. The Canary Islands sit next to one of them.

🌊 The equatorial Pacific, where a thin productive tongue stretches westward from South America, and the high-latitude oceans, green wherever there is light and open water.

⚪ Grey means land or not enough data: areas covered by ice or in polar darkness for much of the year, where satellites cannot see the colour of the sea.

Colours are on a logarithmic scale, from 0.01 to 10 mg per cubic metre: each step is ten times more chlorophyll.

This is the companion of our monthly Spilhaus animation of chlorophyll: that one shows how the ocean breathes season by season, this one shows its long-term average.

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