A vocabulary of landscape — a landscape of words
1054 entries
upwelling
Upwelling is the rising of cold nutrient-rich water from depth to the sunlit surface. It happens where wind blows along a coast and the earth’s rotation deflects the surface water offshore, so deep water has to rise to replace it. It also occurs at the equator and around Antarctica. The nutrients feed plankton, which feeds everything else, so upwelling zones carry the most productive fisheries in the world.
Etymology
The word is a plain English compound and it entered oceanography in the early twentieth century, once the mechanism had been worked out. The deflection responsible is the Ekman transport, named for the Swedish oceanographer who explained why surface water driven by wind moves at an angle to it rather than straight downwind.
Notes
Four coastal upwelling systems dominate: off California, Peru and Chile, northwest Africa, and southwest Africa. Together they cover a very small fraction of the ocean surface and produce a very large share of the world’s catch. They are also why those coasts have deserts and fog: The cold water chills the air above it, which suppresses rain and produces sea fog.