Atlantic Ocean

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The Atlantic is the part of the Earth's world ocean that separates America —to the west— from Europe and Africa —to the east. It extends from the Arctic Ocean in the north to the Antarctic in the south. It is the second largest ocean on Earth after the Pacific. It occupies 20% of the planet's surface, and 26% of the total submerged land. It is also the youngest ocean on the planet, formed 200 million years ago by the division of the supercontinent Pangea.

The Atlantic is an agent of global importance in terms of climate, since the climate of the riparian continents depends to a large extent on its currents. Throughout history it has been a cultural barrier that has separated the so-called Old and New Worlds until the arrival of the Age of Discovery, which meant that the ocean became a point of commercial and cultural exchange. Currently, it has not lost its geostrategic importance, becoming the scene of great battles from the XIX century to being the scene of conflicts in the War cold.

The terrestrial equator artificially divides it into two parts, the North Atlantic and the South Atlantic. Its name comes from the Greek Atlas, one of the titans of Greek mythology. It reaches its maximum depth in the Puerto Rico Trench.

It communicates artificially with the Pacific Ocean through the Panama Canal, naturally through the Strait of Magellan and the Sea of Hoces, with the Indian Ocean through the Suez Canal and southern Africa, and with the Mediterranean Sea through the Strait of Gibraltar.

Origin of name

The Strait of Gibraltar, boundary between the Mediterranean Sea and the Atlantic Ocean.

The word «Atlantic» would come from the titan «Atlas» who possessed, according to the ancient Greeks, the columns that support the sky (in ancient Greek, tlaô, means "to bear" or "to support"), of which the mythical Pillars of Hercules (currently the Strait of Gibraltar) were part. Therefore, for the ancients, this term designated above all the sea that was beyond the strait, as opposed to the Mediterranean Sea. Its name could also come from the Libyan Atlantean peoples, described by Herodotus, who inhabited the North African shores of the Atlantic Ocean and the mountains of the Moroccan Atlas massif, in northwest Africa. During the Middle Ages and until approximately the middle of the XVIII century it was mentioned on maps and navigation charts under the name Mar del Nord or North Sea.

Physical geography

Location and delimitation of the IHO

Features

The Atlantic, as seen from the west coast of Portugal.

The Atlantic is shaped like the letter "S", being the second largest ocean on Earth, after the Pacific, and covers approximately 20% of its surface. Its waters extend over an area of 81,760,000 km² or 106.5 million counting the adjacent seas. Its volume is 354.7 million km³, if the adjacent seas are counted, or 323.6 km³, if the adjacent seas are not counted. consider.

The width of the Atlantic varies from 2,848 km (between Brazil and Liberia) to 4,870 km (between the United States and Morocco). Its maximum width is 11,800 km, in a route that goes from the Gulf of Mexico to Georgia, on the shores of the Black Sea.

The sea ridges located between Baffin Island, Greenland and Scotland have been conventionally established as the boundary between the Arctic Ocean and the North Atlantic Ocean.

To the east, the Strait of Gibraltar forms the boundary with the Mediterranean Sea; to the west, the arc formed by the Caribbean islands separates it from the Caribbean Sea.

To the west there is an artificial connection between the Atlantic and the Pacific through the Panama Canal.

To the southeast, the separation with the Indian Ocean is established, according to modern conventions, by the meridian of 20° E. To the southwest, the divide has been established on the meridian that joins Cape Horn with Antarctica, in the waters of the passage Drake's.

It has an average depth of 3,900 m, which is obtained thanks to a large plateau close to 3,000 m deep that constitutes almost its entire bottom, together with the large depressions that are found on its edges and that reach at 8800 m in the vicinity of Puerto Rico. Despite this, the number of islands is relatively small.

The salinity of the Atlantic is about 36 grams of salt per liter of water and the most fished species are sardines, herring and cod. In addition, it is the most difficult ocean on Earth from a commercial point of view.

Ocean	Area (in km2)	Contents comparison (*)
Atlantic	81 760 000	1
Pacific	165 000	1.91
Indian	75 600 000	0.80
Antarctic Glacial	20 327 000	0.22
Arctic Glacial	14 090 000	0.15

(*) The index is calculated by reference to the Atlantic surface in 1.

Nearby Seas

Principal level: Seas of the Atlantic Ocean

Coastal seas, border seas or adjacent seas, are the seas that are part of the Atlantic, but that due to their own configuration and/or controversies related to their inclusion or not in the set, motivate that the characteristics of the Atlantic are given with or without its seas. The Arctic Ocean itself is a special case, since it corresponds to the definition of a marginal sea, although, depending on the works, it is referred to as a full ocean or as a marginal Atlantic sea. Therefore, the area of the Atlantic varies according to the status given to the Arctic Ocean.

Designation	Location	Area (in km2)
Caribbean Sea	Between Mexico, South America, Central America, Cuba and the Antilles	2 640 000
Mediterranean Sea	Between Africa, Europe and Asia	2 510 000
Gulf of Mexico	Between Mexico, Cuba and the United States	1 550 000
Sea of Norway	Between Norway and Iceland	1 380 000
Greenland Sea	Between Greenland and Iceland	1 205 000
North Sea	Among the British islands, Belgium Netherlands, Germany and Scandinavia	575 000
Baltic Sea, including Kattegat	Between Eastern Europe and Scandinavia	450 000
Black Sea	Between Bulgaria, Georgia, Romania, Russia, Ukraine and Turkey	420 000
Gulf of San Lorenzo	At the end of the San Lorenzo estuary	155 000
Canal de la Mancha	Separate France from Great Britain	75 000
Sea of Azov	In contact with the Black Sea	37 600
Gulf of Venezuela	Contact the Caribbean Sea	17 600
Total seashore without the Arctic Ocean		7 152 600
Arctic Ocean	Around the North Pole	14 090 000
Total coastal seas with the Arctic Ocean		21 242 600

In addition to these coastal seas, other names are used to name specific areas, such as the Argentine Sea, the Cantabrian Sea, the Irish Sea or the Sargasso Sea, which do not always correspond to oceanographic criteria and which mostly respond to geographic-cultural uses. Likewise, some of the coastal seas are in turn divided into other seas, such as the Mediterranean or the Baltic.

Geology

Atlantic Batimetry, noting that almost in the middle of the Atlantic extension runs from north to south a submarine volcanic mountain range (emerged in some islands like Iceland), is the Mesoatlantic Dorsal one of the longest mountain ranges on Earth.

The main characteristic of the seabed (bathymetry) of the Atlantic is a large underwater mountain range that crosses it from north to south, called the Mid-Atlantic Ridge, which forms at the limit of four tectonic plates: Eurasian, North American, and South American. and African.

The ridge extends from Iceland north to about 58° south latitude, reaching a maximum width of about 1,600 km. The water depth above the ridge is less than 2,700 meters in many areas, and some peaks jut out of the water, forming islands.

The ocean floor is generally thought to be fairly flat, although there are plenty of seamounts, as well as deep trenches. The Puerto Rico Trench, in the North Atlantic, is the deepest. In the South Atlantic, the South Sandwich Trench reaches a depth of 8,428 m. A third trench, the Romanche Trench, is located near the equator and is 7,760 m. Shelves on the continental margins make up about 11% of the fund. In addition, there are a number of deep channels that cut the platforms.

Ocean sediments are composed of terrigenous, pelagic, and authigenic materials. Terrigenous deposits consist of sand, mud, and rock particles formed by erosion, weathering, and volcanic activity on land and later transported to the sea. These materials are found abundantly on the continental shelves and are even more so in front of the mouths of large rivers or desert coasts.

Pelagic deposits contain remains of organisms that sank to the ocean floor, including red clays, Thecosomatas and Globigerina, among others. They cover most of the sea floor and vary in thickness between 60 m and 3,300 m; they are thicker in the convergence and water upwelling zones.

Authigenic materials consist of materials such as manganese nodules. They take place where there is little sedimentation or where the currents grade the deposits. Large methane deposits are also found almost always in the deepest areas of the Atlantic basins, for example in the Argentine Basin or in the Gulf of Mexico.

Geological history

Pangea Animation that represents the separation of the continents to the formation of the Atlantic as we know it today.

In ancient times the continents were united in a large continent called Pangea, when the continents known today as Africa and America began to divide, a great void was exposed that was filled with saline water from the Pacific and Antarctic.

The Atlantic began to form about 150 million years ago in the Jurassic era, when the ancient supercontinent called Pangea broke up, giving rise to the formation of great seas between the continental plates that were moving away from each other, separated by the mid-ocean ridges.

Finally, and after the complete separation of America from the old continent, an ocean of approximately 91 million square kilometers was formed.

Geography Notes

The most important straits are: the Strait of Gibraltar and the Strait of Magellan, in terms of artificial naval courses (built by humans) the Panama Canal stands out. Other strategic straits are the Strait of Dover (between the coast of France and the island of Great Britain), the Strait of Florida, the Mona Pass (between the island of Puerto Rico and the Dominican Republic), the Oresund (between Denmark and Sweden) and the Windward Pass.

As for the northernmost connection between the Atlantic and the Pacific, it occurs through waters shared with the Arctic Glacier Ocean by the Northwest Passage, this pass was almost impassable by ships until the end of the century XX the time in which human-induced global warming melted and is melting much of the Arctic polar ice pack.

During the Cold War, a large sector between Greenland-Iceland-United Kingdom, known in the military sphere as GIUK, was an area of great strategic interest and friction between NATO and Soviet Union air and naval forces.

Land

The sea surface is covered with ice in the Labrador Sea, the Denmark Strait, and the Baltic Sea from October to June.

Natural resources

Oil and gas fields, fisheries, marine mammals (seals and whales), sand and gravel aggregates, polymetallic nodules, and gemstones.

Natural hazards

Icebergs are common in the Davis Strait, the Denmark Strait, and the Northwest Atlantic from February to August and have been observed on occasion as far as Bermuda and the Madeira Islands; ships are exposed to ice superstructures from October to May; persistent fog can be a hazard from May to September; there are hurricanes from May to December.

Current environmental issues

See also: Marine pollution and North Atlantic garbage dump.

Some endangered marine species include manatees, seals, sea lions, turtles, and whales; trawling is causing the disappearance of fish schools.

Sewage that spreads from the east coast of the United States, southern Brazil, and eastern Argentina; hydrocarbon pollution in the Caribbean Sea, the Gulf of Mexico, Venezuela, the Mediterranean, and the North Sea; there is industrial pollution in the Baltic, in the North Sea, and in the Mediterranean.

Water characteristics

View of a beach on the island of Orchilla, in Venezuela.

The salinity of surface waters in the open ocean ranges from 33 to 37 parts per thousand and varies with latitude and season. Although the minimum salinity values are found just north of the equator, generally the lowest values are at high latitudes and along the coasts where large rivers flow into the ocean. The maximum salinity occurs at approximately 25° north latitude. Surface salinity is influenced by evaporation, precipitation, river flows, and snowmelt.

Surface temperatures, which vary with latitude, current systems, seasons and reflect the distribution of solar flux as a function of latitude, range from minus 2 to 29 °C. The maximum temperatures take place in the north of the equator, and the minimum in the polar regions. At mid-latitudes, where the maximum variations are, the values can vary by 7 or 8 °C.

The Atlantic consists of four main bodies of water. Central waters are surface water. Intermediate subantarctic water extends to depths of 1000 m. North Atlantic deep water reaches depths of up to 4,000 m. Antarctic water occupies ocean basins at depths greater than 4,000 m.

Due to the Coriolis force, water in the North Atlantic flows clockwise, while in the South Atlantic it is counterclockwise.

The tides are semidiurnal, which means that there are two high tides every 24 lunar hours. Tides are waves that generally move from south to north. At latitudes above 40° north some east-west oscillations take place.

Climate

Thermohaline currents. The Atlantic is an important temperature regulator, sending heat from the tropics to temperate areas.

Hurricane Isabel from the International Space Station. Hurricanes are frequent in the Central Atlantic in the hurricane season and are a serious problem in the coastal countries.

The climate of the Atlantic and its adjacent lands is influenced by surface water temperatures and water currents, as well as winds. Due to the great capacity of the oceans to retain heat, maritime climates are moderate and without extreme seasonal variations. Precipitation can be approximated from coastal weather data and air temperature from water temperature.

The oceans are the most important source of environmental moisture (which is obtained by evaporation). Climatic zones vary with latitude; the warmest areas extend across the Atlantic and north of the equator. The coldest zones are in the high latitudes, and correspond to areas covered in sea ice.

Ocean currents contribute to climate control by transporting warm and cold water to other regions. Adjacent land is affected by winds that are cooled or heated when they blow over these currents. The Gulf Stream, for example, warms the atmosphere of the British Isles and northwestern Europe, and cold water currents cause persistent fog along the northeastern coast of Canada (the Grand Banks) and northwestern Africa.

Tropical cyclones (hurricanes) form off the coast of Africa near Cape Verde and move west toward the Caribbean Sea; Hurricanes can appear from May to December, but are more frequent from August to November. Storms are common in the North Atlantic in winters, making voyages more difficult and dangerous.

Economy

The Atlantic has been extensively explored since the first human settlements along its shores. The Vikings, the Portuguese, the Spanish, among whom Christopher Columbus stands out, were its most famous explorers. After Columbus, European exploration accelerated rapidly, and many new trade routes were established. As a result, the Atlantic was (and still is) the main artery between Europe and America (the old world and the new). Numerous scientific explorations have been carried out, including the German Meteor Expedition, the Columbia University Expedition, and the hydrographic offices of different navies.

The ocean has also contributed significantly to the economic development of the countries that surround it. In addition to being a transportation route, the Atlantic offers deposits of oil, abundant in the sedimentary rocks of the continental shelf, and the richest fishery resources in the world, especially in the waters above the shelves. The most productive areas are the Great Banks of Newfoundland, the continental shelf in Nova Scotia, the Georges Bank on Cape Cod, the Bahamian Banks, the waters around Iceland, the Irish Sea, the North Sea, and the banks of the Falklands. Eels, lobsters and whales have also been caught in large numbers. All these factors give the Atlantic a great commercial value.

Due to the threats posed by oil and hydrocarbon spills, plastics, and the incineration of toxic waste at sea, there are various international treaties to reduce some forms of pollution.