10 julio, 2024

Cold sea of ​​the Peruvian current: what it is, characteristics and causes

What is the cold sea of ​​the Peruvian current?

The cold sea of ​​the Peruvian current is a marine current that occurs on the coast of the Pacific Ocean, south of Peru. This current constitutes the northern part of the Humboldt current, which comes from the central part of the Chilean coasts.

This current was described by the naturalist Alexander von Humboldt, after whom it bears his name. However, Humboldt himself stated that this current was already known since Antiquity by the original settlers of these regions of America.

This phenomenon occurs due to a process called upwelling, which consists of the upwelling of large masses of deep water towards the surface, and with them the nutrients from the seabed are also displaced. The water is green, due to the abundance of plankton.

These waters coming from the seabed have a low temperature, high salinity and a large amount of nutrients, which generates a great diversity of fish species (around 600), resulting in the highest fishing productivity on the planet.

Characteristics of the cold sea of ​​the Peruvian current

– The cold sea of ​​the Peruvian current is located in the eastern Pacific Ocean, on the Peruvian coast, between 5º south latitude (bordering on the tropical sea of ​​Peru) and 18º south latitude (on the border with Chile ), between the coast and 100 km offshore, to the west.

– The current travels in a south-north direction at 28 km per day, parallel to the coastline. At 5º south latitude, it deviates towards the west, towards the Galapagos Islands, until it reaches the terrestrial equator.

– At the equator, this current collides with the waters of the North Equatorial Current, which have a much higher temperature, almost 30 °C. Nowhere else in the world is there such a sharp temperature contrast between currents on either side of the equator.

– The most notable characteristic of the cold sea of ​​the Peruvian current is its temperature. Its waters are particularly cold, being a tropical region. They can measure between 13 and 14 °C in the coldest season and between 15 and 17 °C in the hottest time of the year.

– The cold Peruvian sea waters have a salinity between 33.8 and 35.2 grams of salts per liter of water. The main salts being chlorine, sodium and magnesium.

– Its waters are greenish. This is due to the high concentrations of chlorophyll thanks to the abundance of nutrients, which promotes the growth of phytoplankton.


The cold sea of ​​the Peruvian current is the result of an oceanographic phenomenon known as upwelling. This phenomenon occurs because the trade winds, which blow towards the coast, move the surface layer of the sea to the left, at a right angle to the direction of the wind (due to the Coriolis effect).

The displacement of the superficial layer generates a pressure gradient that sucks deeper waters and, therefore, colder, denser and loaded with nutrients.


The particular characteristics of the cold sea of ​​the Peruvian current, in terms of salinity, temperature and nutrient load, give great economic, climatic and ecological importance.

Economic importance

The cold sea of ​​the Peruvian current is barely 0.1% of the surface of the oceans worldwide. However, more than 10% of world fishing is obtained from it.

It is one of the most productive regions on the planet. It produces more fish per square meter than any other open sea territory.

This high productivity is due to the high nutrient load of the stream waters. Deep waters have abundant nutrients such as nitrate, phosphate, and silicic acid.

When these waters rise to the surface, thanks to upwelling, these nutrients are used by phytoplankton, together with carbon dioxide and solar radiation, to produce organic compounds through photosynthesis.

This high primary productivity is propagated throughout the food chain, producing large numbers of zooplankton, filter feeders, fish, birds, and marine mammals.

The Peruvian anchovy fishery is the largest single-species industry in the world.

climatic importance

The particularly cold waters of the Peruvian Current cool the atmosphere of the Earth’s surface. This results in little evaporation and, therefore, low rainfall.

Thus, the climate of the Peruvian coasts is particularly dry, characterized by sandbanks and coastal deserts. These coasts have a lower temperature than would correspond for an equatorial latitude.

Similarly, the Galapagos Islands have a much less rainy climate thanks to the effects of the current.

ecological importance

The cold sea waters of the Peruvian current are home to great biodiversity. Being a unique ecosystem in the world, with a very high productivity, it has been designated as one of the 200 priority ecoregions for conservation worldwide.

Most conservation programs aim to protect keystone species, those that have a positive effect on other species, such as sea otters, anchoveta, humpback whales, and krill.

The South Pacific sea otter (feline lontra) that inhabits the Peruvian and Chilean coasts, guarantees the ecological balance of the cold sea of ​​Peru. It feeds on the sea urchin, controlling its population size.

If otters decrease in number and urchins increase in population density, they could cause damage to kelp forests, which in turn are food and habitat for many other species.

The anchovy (Engraulis ringens) and krill (euphausiaceous crustaceans) are the main food for other species such as the humpback whale (Megaptera novaeangliae).

These species are very important in maintaining the marine food web. The decrease in the size of their populations could generate catastrophic consequences in ecological terms.


The western coast of South America receives head-on the climatic changes coming from the Pacific.

This is affected by events such as El Niño (hot) and La Niña (cold), which alter the rainfall, wind, temperature and oxygen concentration of sea currents for several months. This region is periodically subjected to enormous climatic “stress”.


Humboldt current. Retrieved from es.wikipedia.org.
Upwelling. Retrieved from en.wikipedia.org.

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