COLD SEA OF ​​THE PERUVIAN CURRENT: CHARACTERISTICS, CAUSES - ENVIRONMENT - 2025

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 is named. However, Humboldt himself stated that this current was already known since ancient times by the original settlers of these regions of America.

Humpback whale (Megaptera novaeangliae), key species of the Cold Sea of ​​the Peruvian Current

This phenomenon occurs due to a process called upwelling, in which the wind carries the most superficial layer of the ocean. A vacuum is generated that is filled with a mass of deep water.

These waters from the seabed have a low temperature, high salinity and a large amount of nutrients, resulting in the highest fishing productivity on the planet.

General characteristics

The cold sea of ​​the Peruvian current is located in the eastern Pacific Ocean, on the Peruvian coast, between 5º south latitude (bordering the tropical sea of ​​Peru) and 18 ° 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 northern equatorial current, which have a much higher temperature, almost 30 ºC. Nowhere else in the world is such a sharp contrast in temperature between currents on both sides of the equator.

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

The waters of the cold Peruvian sea 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 in color. This is due to the high concentrations of chlorophyll a, due to the abundance of nutrients, which promotes the growth of phytoplankton.

Causes

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 right angles to the wind direction (due to the Coriolis effect).

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

Graphic representation of the upwelling phenomenon. Lichtspiel, via Wikimedia Commons

Importance

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 the world's fishing is obtained from it.

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

This high productivity is due to the high nutrient load of the stream waters. Deep waters are rich in nutrients like nitrate, phosphate, and silicic acid.

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

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

Peru's anchovy fishing industry is the largest monospecific 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 sandy areas and coastal deserts. These coasts have a lower temperature than would correspond to an equatorial latitude. Similarly, the Galapagos Islands have a much less rainy climate thanks to the effects of the current.

Ecological importance

The waters of the cold sea 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 conservation ecoregions worldwide.

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

The South Pacific sea otter (Lontra felina) 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 the otters decrease in number and the urchins increase their population density, they could cause damage to the marine macroalgae forests, which in turn are food and habitat for many other species.

The anchovy (Engraulis ringens) and the Krill (eufausiaceous crustaceans) are the main food of other species such as the humpback whale (Megaptera novaeangliae).

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

Alterations

The western coast of South America faces the climatic alterations 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 the ocean currents for several months. This region is periodically subjected to enormous climatic “stress”.

References

1. Humboldt current. (2018, December 9). Wikipedia, The Free Encyclopedia. Consultation date: 10:08, December 30, 2018 from wikipedia.org.
2. Institut de recherche pour le développement. (2009). The Humboldt Current: the ecosystem of the extremes. Actualité scientifique 310.
3. Michael Akester, M. (2014). Key species in the Humboldt current system: Chile - Peru. Bulletin of the United Nations System in Peru (4): 6-7.
4. Schneider, W., R. Fuenzalida, R. Núñez, J. Garcés-Vargas, L. Bravo and D. Figueroa. (2007). Discussion of the Humboldt current system and water masses in northern and central Chile. Science and Technology of the Sea Magazine, Vol. 30 (1): 21-36.
5. Wikipedia contributors. (2018, December 18). Upwelling. In Wikipedia, The Free Encyclopedia. Retrieved 10:11, December 30, 2018, en.wikipedia.org.