: Winds blowing across the ocean surface push water away. Water then rises up from beneath the surface to replace the water that was pushed away. This process is known as “upwelling.”
Upwelling occurs in the open ocean and along coastlines. The reverse process, called “downwelling,” also occurs when wind causes surface water to build up along a coastline and the surface water eventually sinks toward the bottom.
Water that rises to the surface as a result of upwelling is typically colder and is rich in nutrients. These nutrients “fertilize” surface waters, meaning that these surface waters often have high biological productivity. Therefore, good fishing grounds typically are found where upwelling is common.
There are a number of smaller upwelling regions around the world, but the main coastal upwelling systems are found on the eastern side of the ocean basins, next to the subtropical gyres of the Atlantic and Pacific, and associated with the cold eastern boundary current:
The Canary Current upwelling system
The Benguela Current upwelling system
The California Current upwelling system
The Peru Current upwelling system