The Humboldt Current, also known as the Peru Current, is a cold, low-salinity ocean current that travels northward along the western coast of South America. It extends 500–1,000 kilometers (310–620 miles) offshore, originating from southern Chile and flowing up to northern Peru. This current significantly influences regional climate, marine ecosystems, and the fishing industry along the South American coast.
Current Formation and Properties
The Humboldt Current originates from cold, deep waters in the Antarctic region, driven northward by prevailing winds, specifically the southeast trade winds, and the Coriolis effect, a force resulting from the Earth’s rotation that deflects moving objects. It is an eastern boundary current, flowing towards the equator along the western edge of a continent.
As the cold waters move northward, they encounter the continental shelf off the coast of South America. This interaction, combined with wind patterns, causes a phenomenon known as upwelling. Upwelling brings nutrient-rich waters from the ocean depths to the surface. These waters are characterized by their low temperature, often as low as 16 °C (61 °F) off the coast of Peru, which is unusually cold for tropical latitudes where temperatures typically exceed 25 °C (77 °F).
The upwelling process is particularly pronounced off Peru year-round, while off Chile it occurs mainly during spring and summer. This consistent influx of cold, nutrient-dense water, containing high levels of nitrates and phosphates, creates a highly productive marine environment. The Humboldt Current is one of the most productive eastern boundary current systems globally.
Shaping Coastal Climates
The Humboldt Current exerts a significant cooling influence on the climate of adjacent landmasses, particularly in Chile, Peru, and Ecuador. The cold waters cool the overlying air, leading to atmospheric stability. This stability prevents the formation of rain-producing clouds, resulting in arid conditions along the coast.
This interaction is a primary reason for the existence of the Atacama Desert in northern Chile and coastal areas of Peru, which are among the driest places on Earth. Despite the lack of rainfall, coastal fog, or “camanchaca” in the local Aymara language, frequently forms. This dense marine fog provides moisture to the otherwise parched landscapes, supporting specialized ecosystems and enabling some plant life to survive.
Engine of Ocean Life
The upwelling process within the Humboldt Current is the primary driver of its high biological productivity. By bringing nutrient-rich waters from the deep ocean to the surface, it fuels massive blooms of phytoplankton. These microscopic organisms form the base of a highly productive marine food web, supporting a vast array of marine life.
This ecosystem is home to large populations of pelagic fish such as anchovies, sardines, and jack mackerel, making it one of the world’s most productive fishing areas. The Humboldt Current accounts for approximately 18-20% of the total worldwide marine fish catch. The high productivity also supports numerous marine mammals, including eared seals and cetaceans, and a diverse array of seabirds like the Humboldt penguin, Peruvian booby, and Chilean pelican.
Influence of Ocean Cycles
Large-scale climate patterns, particularly El Niño events, significantly alter the Humboldt Current. During an El Niño, the waters of the current warm, which suppresses the upwelling process. This warming and reduction in upwelling leads to a decrease in nutrient availability at the surface, impacting primary productivity.
These changes have cascading ecological and economic consequences. Fish populations, especially anchovies and sardines, often decline or shift their distribution, leading to significant impacts on fisheries. Seabird populations, reliant on these fish, can also suffer die-offs. Conversely, La Niña, the opposite phase of El Niño, is characterized by cooler-than-average sea surface temperatures and can intensify the upwelling, potentially leading to increased productivity.