The Humboldt Current (from the name of the naturalist Alexander von Humboldt that measured this cold-water current in the 1840's) is a cold current running northwards along the Pacific shore of South America.
It carries cold-water (with temperature as low as 16 Celsius) enriched in nutrients allowing for the development of a very high-productivity ecosystem.
The current has a strong cooling effect on the climate of Chile, Peru and Ecuador. The very arid climate of the Atcama desert in northern Chile, and of other coastal areas of Peru and Ecuador, is also due to the presence of this cold water that reduces the evaporation from the ocean affecting the amount of rain.
The current upwelling (rising of cold water from the depths) is periodically disturbed by El Nino events with changes in climate and reduction in fish productivity.