ATLANTIC OCEAN: GEOLOGICAL ORIGIN, CHARACTERISTICS, FLORA AND FAUNA - ENVIRONMENT - 2024

The Atlantic Ocean is the second largest body of water in the world, second only to the Pacific Ocean. It occupies a fifth of the total surface of the planet and its extension covers approximately 26% of the total sea floor. It is artificially divided along the equator, between the sides of the North Atlantic and the South Atlantic.

This ocean separates the American continent (located on its west side) from the European and African continents (located on its east side). It crosses the terrestrial sphere from pole to pole, extending from the north polar zone, where it borders the Arctic Ocean; to the south pole, where it meets the Antarctic Ocean.

The Atlantic Ocean occupies about 20% of the earth's surface. Source: pixabay.com

It is mainly made up of four bodies of water. The central one is that of the surface and 1000 meters deep is the intermediate subantarctic water. The deep waters are the North Atlantic, reaching a depth of 4000 meters. Finally there are the Antarctic waters, which exceed 4000 meters deep.

Geological origin

At the end of the Paleozoic era and at the beginning of the Mesozoic, approximately three hundred million years ago, there was a supercontinent called Pangea. During the Jurassic period, a rift formed on this continent that ran from what geologists have called the ancient Thetis Ocean to the western Pacific Ocean.

This fracture generated the separation between the continental mass that today makes up North America and that of the African continent. The void between these was filled by saline water from the Pacific and Antarctic oceans, thus forming the Atlantic Ocean.

Keep in mind that this process was gradual. First the North-Central Atlantic zone was formed; When America finished separating, the Atlantic Ocean had an area of ​​approximately 91 million km ².

The South Atlantic was formed later, in the Cretaceous period, during the second phase of separation from Pangea. This phase is marked by the fragmentation of Gondwana, a supercontinent made up of the mass of South America, Africa, Australia, India and Antarctica.

The South Atlantic made its way as South America moved westward away from Africa. This process was gradual and uneven, opening from the south to the north in a similar way to the zipper of a pants.

characteristics

Location

The Atlantic stretches from the north from the Arctic Ocean to its southernmost point, the Antarctic Ocean. Its width goes from the coasts of the American continent to the west, to those of Europe and Africa located on its eastern side.

Dimensions and surface

The surface of the Atlantic Ocean has a shape similar to the letter S. Its current extension is about 106.4 million km ², which represents approximately 20% of the earth's surface. This makes it the second largest ocean in the world after the Pacific.

It has a volume of 354.7 million km ³ counting the surrounding seas. If these are not counted, it can be said that the Atlantic has a volume of 323.6 km ³.

Its width ranges from the 2,848 km between Brazil and Liberia, and the 4,830 km that separate the United States from North Africa.

Depth

The Atlantic Ocean has an average depth of about 3,900 meters. This is largely due to the presence of a large plateau located 3,000 meters deep that covers almost the entire ocean floor.

At the edge of this plateau there are several depressions that can exceed 9000 meters in depth. These depressions are near the territory of Puerto Rico.

Salinity

The Atlantic Ocean is the saltiest in the world, having about 36 grams of salt for every liter of water. The areas with the highest concentration of salt are at about 25 degrees north and south latitude; North of the Atlantic there is a lower degree of salinity since evaporation in this area is much lower.

The reason its waters are so salty is the flow of its currents. When the cold surface of the North Atlantic sinks, moving south towards Antarctica, it activates a pattern of movement of ocean currents.

According to this pattern, a large mass of hot water from Europe moves to lessen the effect of continental cooling.

Why is it saltier than the Pacific Ocean?

The Pacific Ocean does not have the same thermal self-regulation mechanism as the Atlantic; for this reason its waters remain sweeter.

The mountain formations of North America and the South American Andes make it impossible for the masses of water vapor generated in the Pacific to move towards the Atlantic Ocean. Therefore, precipitation falls into the same ocean as if fresh water were recycled.

If those mountains did not exist, the rain and snowfall would occur inland and would end up flowing into the Atlantic through rivers, so they would not return to the Pacific.

In addition to this, it is also influenced by the fact that steam from the tropical Atlantic and the Caribbean Sea ends up falling into the Pacific as a result of the trade winds that carry it through Central America.

In this process, some 200,000 cubic meters of fresh water are mobilized per second, an amount equivalent to that which moves at the mouth of the Amazon River, the longest and with the highest flow on the planet.

Geography

North Atlantic

The North Atlantic limits geographically with several zones. Its eastern limits are marked by the Caribbean Sea, the southwestern Gulf of Mexico, the Gulf of Saint Lawrence and the Bay of Fundy (Canada).

In its northernmost part it borders the Davis Strait, from the Greenland area to the Labrador Coast (Canada). The boundary also touches the Greenland and Norwegian Seas and ends at the British Isles of Shetland.

On the east side it meets the Scottish, Irish and Mediterranean seas, as well as the Bristol Channel (border between Wales and England) and the Bay of Biscay, which touches the coasts of Spain and France.

To the south, in addition to the line of the equator that separates it imaginatively from the other half of the Atlantic, it also meets the coasts of Brazil to the southwest and the Gulf of Guinea in the southeast.

South Atlantic

The southwestern limit of the South Atlantic is determined by Cabo de Hornos (Chile), the southernmost point of America, which reaches the Antarctic zone of Tierra del Fuego, marked by the limit of the Strait of Magellan (between Cabo de Vírgenes and Cabo Holy Spirit).

On the west side it limits with Río de la Plata (Argentina). Likewise, the northeast part borders the Gulf of Guinea.

Río de la Plata flowing into the Atlantic. Source: Earth Sciences and Image Analysis Laboratory, NASA Johnson Space Center The southern part reaches as far as Antarctica and the farthest southeast part borders the Cape of Needles (South Africa).

geology

The continents that formerly made up the land mass known as Gondwana today continue to separate several centimeters a year around the Central Atlantic submarine ridge, a chain of mountains that cuts its way from north to south between the two continents and breaks the plain of the sea ​​bottom.

This mountain range is about 1500 km wide and extends from the north of Iceland to 58 degrees south latitude. The accidents of its topography exceed those of any surface mountain range since it usually suffers from eruptions and earthquakes. Its height is between 1000 and 3000 meters above the seabed.

The submarine elevations are distributed from east to west across the Central Atlantic submarine ridge. This divides the eastern and western ocean floors into basins called abyssal plains.

The abyssal plains located near the American continent are more than 5000 m deep. These are the North American basin, the Guianas, the Brazilian basin and Argentina.

The area of ​​Europe and Africa is bordered by shallower basins. These are the Western European Basin, the Canary Islands, Cape Verde, Sierra Leone, Guinea, Angola, the Cape and Cape Agujas.

There is also a West Atlantic-Indian basin that runs through the southern part of the Central Atlantic mountain range.

Weather

The Atlantic climate is the product of the temperature of the surface waters and the underwater currents, as well as the effect of the winds. Since the ocean retains heat, it does not show great seasonal variations; it has tropical areas with a lot of evaporation and high temperatures.

The climatic zones of the Atlantic vary according to latitude. The hottest places are in the North Atlantic and the cold zones are in high latitudes where the oceanic surface is crystallized. The average temperature is 2ºC.

The currents of the Atlantic Ocean help regulate global temperature as they transport warm and cold waters to various territories. The Atlantic winds that accompany the ocean currents transport the humidity and thermal variations that regulate the climate in the continental areas that border the ocean.

For example, currents from the Gulf of Mexico raise the temperature of Great Britain and the northeast region of Europe. Instead, cold currents keep the northeast region of Canada and the northwest coast of Africa cloudy.

Hurricane season

During August and November the hurricane season occurs. This is because hot air from the surface rises and condenses as it collides with cold currents in the atmosphere.

Hurricanes grow with the mass of water, but when they come into contact with the land they lose their strength, first becoming a tropical storm until they disappear completely. These generally form in the African adjacencies and move in an eastern direction, towards the Caribbean Sea.

Flora

There are millions of species of plants that inhabit the Atlantic Ocean. Most live in shallow areas since they need sunlight to carry out the photosynthesis process.

These can be attached with their roots to the bottom of the ocean or they can be found floating freely in the water.

Algae

Various kinds of seaweed are common. These plants are elongated and live mainly near rocky shores.

There is a type of giant algae that can grow to a length of 200 feet, and there are also small species that have only one branch and are about three feet long. One of the most common species is Ascophyllum nodosum.

Algae have more than 70 nutrients in their physical constitution, including minerals, vitamins, proteins, enzymes and trace elements.

These plants are collected to make fertilizers since it has been shown that they serve to accelerate the growth of vegetables, protect them from diseases and, in addition, favor flowering and fruit growth.

Sea grass

Seagrass is a plant that has flowers and produces oxygen. It is found mainly in the Gulf of Mexico.

It is very important for the marine ecosystem since it maintains the clarity of the water and also serves as food and even habitat for many species of small animals since they can hide under its leaves.

There are 52 species of seagrass. They are generally greenish-brown in color and are rooted on the ocean floor. Some of its species are turtle grass, star grass, manatee grass, halophila and Johnson grass.

Phytoplankton

One of the most abundant and important marine forms for the Atlantic Ocean ecosystem is phytoplankton. This is a very basic type of plant that a large number of marine animals eat, including whales.

Phytoplankton is imperceptible to the human eye since it is a single-celled plant. Phytoplankton agglomerations are generally found far from shore.

Fauna

The Atlantic Ocean is home to a large number of animal species, both vertebrates and invertebrates, fish, mammals and reptiles.

- Most representative species

Atlantic walrus

The Odobenus rosmarus rosmarus is a species of walrus that lives in northeast Canada, Greenland and the Svalbard archipelago (Norway).

Males weigh between 1200 and 1500 kg, while females are only half the size, between 600 and 700 kg.

sea ​​cow

Sea cow. Source: Cedricguppy - Loury Cédric The Trichechus manatus is a very large species of sirenid mammal. It can measure about three meters and weigh 600 kilograms.

Different varieties of this species can be found from the southern United States to the coastal areas of the Caribbean Sea and northeastern South America. It is in danger of extinction because it was heavily hunted during the 20th century.

Red tuna

Thunnus thynnus is a species of fish that can be about three meters long and weigh about 900 kilograms. They are very fast since they can reach 65 kilometers per hour when they are hunting or when they are escaping from a predator.

They are migratory animals capable of periodically crossing more than eight thousand kilometers along the Atlantic. During the winter they feed in the waters of the North Atlantic and when March arrives they will reproduce in the warm waters of the Mediterranean Sea.

Herring

The Clupea harengus has an average length of about 30 cm. It is located in the North Atlantic and tends to migrate between the coasts of Norway and those of Germany, depending on the climatic variation and its reproduction cycles.

Although it is a species that is commonly traded and consumed, it is not endangered; rather, its population tends to grow.

Green turtle

The Chelonia mydas is found in all the tropical seas of the world. It is the largest of the Cheloniidae family, which is comprised of the hard-shelled species of sea turtles.

Corals

In the depths of the Atlantic, the formation of coral reefs is also common. One of the most common species is the Lophelia pertusa, which grows especially in cold waters.

The largest known reef of Lophelia pertusa is found in the Lofoten Islands (Norway), which is 35 kilometers long. This is formed in deep areas fixing on soft substrates.

- Threats to the fauna of the Atlantic

Trawling

The greatest threat to animal species in the Atlantic Ocean is trawling. This technique is carried out by fishing vessels from many countries.

The use of giant nets implies that the fishing practice is not selective, since 50% of the species caught have no commercial or consumption value for humans. In addition, species considered in danger of extinction and a large number of immature specimens, useless for consumption, usually fall into these networks.

The specimens returned to the sea after being caught by the nets have practically no chance of survival. It must also be taken into account that trawling damages the habitat of the species, breaking coral and dragging sponges.

Oil exploitation

Another great threat to the Atlantic ecosystem is the oil activity that takes place in it, since a large amount of waste falls into the ocean polluting its waters. There have been high-profile cases of large spills:

- In 1979 the Ixtoc I well, located in the Gulf of Mexico, burst and spilled approximately 535,000 tons of oil.

- In June 1989 the oil tanker called World Prodigy hit the Brenton reef, located in Newport (United States); this generated an oil slick that reached an extension of 8 kilometers in diameter.

Countries with coasts in the Atlantic

America

- Argentina.

- Old and bearded.

- Bahamas.

- Belize.

- Barbados.

- Canada.

- Brazil.

- Costa Rica.

- Cuba.

- Colombia.

- U.S.

- Dominica.

- Granada.

- French Guiana.

- Guatemala.

- Haiti.

- Guyana.

- Honduras.

- Mexico.

- Jamaica.

- Nicaragua.

- Puerto Rico.

- Panama.

- Dominican Republic.

- St. Vincent and the Grenadines.

- Saint Kitts and Nevis.

- Suriname.

- Venezuela.

- Uruguay.

- Trinidad and Tobago.

Africa

- Benin.

- Angola.

- Cape Verde.

- Cameroon.

- Gabon.

- Ivory Coast.

- Ghana.

- Gambia.

- Guinea-Bissau.

- Guinea.

- Liberia.

- Equatorial Guinea.

- Mauritania.

- Morocco.

- Namibia.

- Republic of Congo.

- Nigeria.

- Democratic Republic of Congo.

- Senegal.

- Sao Tome and Principe.

- Sierra Leone.

- Togo.

- South Africa.

Europe

In Europe only a few countries have direct access to the Atlantic Ocean. These are the following:

- France.

- Spain.

- Iceland.

- Ireland.

- Norway.

- UK.

- Portugal.

Economic importance

Historically, maritime travel across the Atlantic Ocean has been fundamental for the economies of Europe and America, since all the great exchanges of products between these two continents are carried out in this way.

In addition, the Atlantic plays a fundamental role in the world production of hydrocarbons because sedimentary rocks with oil and gas deposits are found under the continental shelf. The Caribbean Sea, the North Sea and the Mexican Gulf are the most relevant areas for the industry.

Obviously, the importance of fishing activity must be taken into account. Some of the fish most in demand on the international market are cod, herring, hake and mackerel, which are copiously extracted from the Atlantic waters.

Geopolitical importance

The Atlantic Ocean has been a fundamental stage for the development of world geopolitics since ancient times.

Columbus's trip can be considered the first great milestone in its history because it marked the connection between the Old and New World and the beginning of the largest colonization process in history.

The European countries that led this process strengthened their supremacy thanks to their control over the West Indies; we refer to Spain, Portugal, England and France.

Since 1820, the geostrategic positions of the Atlantic have been jealously protected by the United States with the application of the Monroe doctrine, which has justified the policy of maritime interventions in countries such as Haiti, the Dominican Republic, Panama and Cuba.

The Atlantic was one of the main stages of the First World War since, through it, the United States transported all its war material to Europe.

References

1. Bronte, I. “The geopolitics of the oceans” (January 19, 2018) at the University of Navarra. Retrieved on July 18, 2019 from the University of Navarra: unav.edu
2. Buitrago, J., Vera, VJ, García-Cruz, MA, Montiel-Villalobos, MG, Rodríguez-Clark, KM, Barrios-Garrido, H., Peñaloza, CL, Guada, HJ and Solé, G. "Green turtle, Chelonia mydas ”. (2015) in the Red Book of Venezuelan Fauna. Retrieved on July 18, 2019 from the Red Book of Venezuelan Fauna: animalsamenazados.provita.org.ve
3. Miller, K. "What Plants Live in the Atlantic Ocean?" (July 21, 2017) in Sciencing. Retrieved on July 18, 2019 from Sciencing: sciencing.com
4. "The bluefin tuna" (October 7, 2013) from National Geographic. Retrieved on July 18, 2019 from National Geographic: nationalgeographic.es
5. "The misuse of the ocean. Pollution at sea ”(no date) from ILCE Digital Library. Retrieved on July 18, 2019 from the ILCE Digital Library: Bibliotecadigital.ilce.edu.mx