Britannica Sources used in this answer

Why are upwelling regions off Peru and northwestern Africa biologically productive?

Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

World map showing major ocean current systems, with arrows indicating the direction and speed of warm and cold currents in the Atlantic, Pacific, Indian, Southern, and Arctic Oceans. Warm currents are marked in red and cold currents in blue, with currents labeled by name and symbols denoting those that reverse direction seasonally. A legend explains current speed categories and color codes. — ocean current Major ocean current systems of the world.

Upwelling regions off the coasts of Peru and northwestern Africa are among the most biologically productive areas in the world because they facilitate the transport of nutrient-rich deep water to the surface.1

This process is driven by the combined effects of surface winds—such as the trade winds—and the rotation of the Earth, which work together to move surface waters away from the coast. As this surface water is displaced, it is replaced by colder, deeper water that is abundant in essential nutrients.2314

When these nutrients reach the sunlit surface layers, they trigger rapid growth and reproduction of phytoplankton. This surge in primary production provides a massive food supply for zooplankton and higher-level consumers, including nekton and various fish species. Consequently, these regions support some of the world’s most significant fisheries, as the high concentration of plankton creates a thriving, nutrient-dense environment for marine life.125