Тынық мұхитының Гумбольдт ағысы

Current of the Pacific Ocean

The Humboldt Current, also called the Peru Current, is a cold, low salinity ocean current that flows north along the western coast of South America. It is an eastern boundary current flowing in the direction of the equator, and extends offshore. The Humboldt Current is named after the German naturalist Alexander von Humboldt even though it was discovered by José de Acosta 250 years before Humboldt. In 1846, von Humboldt reported measurements of the cold water current in his book Cosmos. This is highly uncharacteristic of tropical waters, as most other regions have temperatures measuring above 25 °C (77 °F). Upwelling brings nutrients to the surface, which support phytoplankton and ultimately increase biological productivity. It accounts for roughly 18 20% of the total worldwide marine fish catch. The species are mostly pelagic: sardines, anchovies and jack mackerel. The system's high productivity supports other important fishery resources as well as marine mammals (eared seals and cetaceans) and seabirds. Periodically, the upwelling that drives the system's productivity is disrupted by the El Niño Southern Oscillation (ENSO) event, often with large social and economic impacts. The Humboldt has a considerable cooling influence on the climate of Chile, Peru and Ecuador. It is also largely responsible for the aridity of the Atacama Desert in northern Chile and coastal areas of Peru and also of the aridity of southern Ecuador. Marine air is cooled by the current and thus is not conducive to generating precipitation (although clouds and fog are produced).

The trade winds are the primary drivers of the Humboldt Current circulation.]] The productivity of the Humboldt Current System is strongly affected by El Niño and La Niña events. During an El Niño event, the thermocline and upper region of the OMZ deepen to greater than 600 m. This causes a loss of nitrogen and decrease in export of carbon. El Niño also causes poleward currents to increase in velocity. During non El Niño years, productivity is very high due to the high nutrient contents, nitrogen recycling through processes such as denitrification, increased carbon export, and remineralization. During El Niño events, fish abundance and distribution are significantly affected, often leading to stock crashes and cascading social and economic impacts. These events have led to sequential changes, where sardines and anchovies have replaced each other periodically as the dominant species in the ecosystem. These species changes can have negative consequences for the fishing industry and the economies of the countries that fish the system. The anchoveta fishery in Peru was booming during the 1960s. In 1970, catches were reported to exceed 12 million tons per year. This accounted for 20% of the world's catches. An El Niño event occurred during 1972 and caused the anchoveta population to collapse. However, sardine populations saw a dramatic increase in the next 15–20 years. Consequently, sardine fisheries grew in this "regime shift".