Antarctic Ocean: Geological Origin, Climate, Flora And Fauna

The Antarctic Ocean – also known as the Southern or Southern Ocean – is one of the parts that make up the world ocean and is characterized by being the second smallest after the Arctic Ocean. The delimitations of the Antarctic are young, since they were established in 2000, under the Antarctic Treaty.

In fact, the extent and existence of this ocean have been the subject of disputes, especially between adjacent countries. For this reason, the Antarctic became a constant topic of conversation among the members of the International Hydrographic Organization, trying to reach an adequate consensus on oceanic limitations.

Antartic Ocean

The Antarctic Ocean is characterized by completely surrounding the Antarctic territories. In addition, this and the Arctic are the only oceans to completely surround a geographic space.

The surface of the Antarctic comprises a number of peripheral seas, such as the Scotia Sea, the King Haakon VII Sea, the Weddell Sea, the Lazarev Sea, the Riiser Larsen Sea, the Cosmonaut Sea, and the Sea of ​​Cosmonauts. of Cooperation. It also has some inland islands, such as Inaccessible Island or Roosevelt Island.

This means that the Antarctic includes all the waters that are located in the southern hemisphere since it covers about 360 ° in longitude. One of the main characteristics of the Antarctic is that the most important ocean basins in the south converge there; In addition, it has the maritime surface with the deepest layers of water.

Similarly, the Antarctic has the largest ocean current called the Antarctic Circumpolar Current. There the waters of the Atlantic, Pacific and Indian oceans are connected.

This current influences the climate that develops throughout the planet because it carries with it up to 145 million cubic meters of oceanic liquid from west to east for 20,000 kilometers at a speed of half a meter per second. Thanks to this route, global heat is distributed and patterns of temperatures and rains are established.

Geological origin

The origin of the oceans

4.5 billion years ago there were countless volcanoes on Earth, the activity of which expelled large pools of magma, a viscous and burning liquid from melting rocks. The magma was composed of huge amounts of gas, which allowed the formation of the first atmosphere .

This first atmosphere, called “primitive” by researchers, was rich in water vapor, since the Earth’s climate was too hot to store liquid water. With the passage of time, the Earth cooled down and the water vapor began to condense, turning liquid and manifesting itself through precipitation.

This rain accumulated in the basins and in all those hollow areas, originating the lakes and little by little some seas and the first oceans.

Over time the composition of the oceans was changing although the amount of water remained the same.

The water of the oceans

At the beginning of the formation of the oceans the water was fresh. However, for millions of years they were filled with biological materials and mineral salts that were transported by rivers.

These salts were the result of the decomposition of rocks and gases that were emitted by volcanoes. Thanks to this phenomenon the water in the oceans became salty.

The bottom of the oceans

The ocean floor is not flat but has a mountainous relief; in addition, it is made up of a fragmented crust.

Therefore, the ocean floor is made up of large mountain ranges whose width and height are approximately four kilometers and extend along the ocean for 60,000 kilometers.

If the water in the oceans disappeared, what would be visualized would be a landscape full of plains, volcanoes, mountain ranges and deep trenches; that is, a very irregular relief.

Origin of the Antarctic ocean

The origin of the Antarctic Ocean as we know it happened when the Antarctic territories were formed. This happened 35 million years ago, when Antarctica separated from Gondwana.

During the Cambrian period it can be said that Gondwana enjoyed a temperate climate, so that the western area of ​​Antarctica was within the northern hemisphere while East Antarctica was located on the equator; some invertebrates and trilobites thrived on the sea beds of this area .

Later, in the Devonian period, Gondwana moved to other latitudes, causing its climate to cool. However, scientists found fossilized remains of tropical terrestrial plants that germinated at this time.

The glaciation began at the end of the so-called Devonian period due to the fact that Gondwana was notoriously approaching the south pole, notably cooling the climate of the region.

The Antarctic Peninsula, as it is known today, began its formation during the Jurassic period; This allowed the islands to gradually surface. Ammonites arose in these waters and there were also some southern dinosaurs such as Glacialisaurus .

Previously, only the existence of a series of seas that surrounded Antarctica that had formed during the Gondwana separation was affirmed; however, in more recent decades it was decided to group these ocean currents under the name of the Antarctic or Southern Ocean.



Due to its circular length of 360 degrees, the Antarctic Ocean only has limits with the other oceans: the Pacific, the Indian and the Atlantic.

The regions closest to Antarctica are the countries of Argentina and Chile; however, the Antarctic currents do not reach the coasts of these places. Regarding its coordinates, the Antarctic Ocean is located at 70 ° S and 150 ° W.


In relation to the dimensions of the Antarctic Ocean, it can be established that it has an average depth of 3,270 meters, while its maximum depth reaches 7,235 meters; This has been recorded in the South Sandwich Trench.

On the other hand, the coastal length of this ocean covers about 17,968 kilometers, and has a series of islands such as Possession, Berkner Island, Roosevelt Island, Guest Island and Scott Island, among others.


The area of ​​the Antarctic Ocean is about 20,327,000 square kilometers, making it the second smallest ocean; its younger brother is the Arctic Ocean, with 14 million square kilometers.

The largest ocean is the Pacific with 161 million, followed by the Atlantic with 106 million; on the other hand, the Indian Ocean has 70.56 million square kilometers.


The geography of the Antarctic Ocean is characterized by its bile plateaus that have been formed by inlandsis and glaciers. A large number of pieces of these plateaus are connected to glaciers located on the mainland, causing them to break up and form icebergs – or icebergs – and ice fields.

As a consequence of global warming, these plateaus are massively melting, causing the water level to rise excessively.

The geography of the Antarctic Ocean is made up of a series of seas and islands that are part of the territories of this oceanic mass.

– Islands

Isla Fisher

Fisher Island is an insular territory that is completely covered in ice and is about eight miles long. It is located north of the Edward VII peninsula and at the western end of Sulzberger Bay.

This territory was revealed thanks to a series of reconnaissance carried out by the USGS and by aerial photos of the US Navy in 1959. In 1966 it was named by the US-ACAN in honor of Wayne Fisher, who belonged to the State Department of the country. North American.

Inaccessible Island (Dellbridge)

It is a small rocky island that is part of the Dellbridge Islands. It is located one mile from Cape Evans and Ross Island. Inaccessible Island is one of the most important of this group, as it never has snow and rises to 95 meters.

This territory was discovered during the Discovery Expedition, between 1901 and 1904, under the direction of the explorer Robert Falcon Scott. It was so called since the expeditionists had many difficulties to reach it.

Inexpressible Island

It is a rocky island located in the Terra Nova Bay of Antarctica. This territory was used by members of the Terra Nova expedition team and there is a very important ice cave that is protected by the Antarctic Treaty.

The Terra Nova expedition was carried out in 1910 by Robert Falcon Scott, who brought together several groups of explorers. During one of the investigations on this island, the ship that was supposed to search for Scott’s team was stranded on the ice, forcing the expeditionists to spend the winter in that territory.

To survive, Scott’s men built a cave and fed on penguins and seals. They also built a reservoir in the moraine, which was later named “the gate of hell.”

During this period men suffered from hunger, frostbite, and dysentery. Consequently, they left the island in 1912 crossing the Drygalski glacier. Despite disease and the ravages of dysentery, they made it to Hut Point alive.

– Seas

Drake Passage or Sea of ​​Hoces

The Drake Passage is called a maritime section that separates Antarctica from South America, between the South Shetland Islands (Antarctica) and Cape Horn (Chile). This passage is sometimes referred to as “narrow”; however, this definition is not adequate.

In addition, it is the southernmost communication route between the Atlantic Ocean and the Pacific Ocean.

As for its limits, to the east it borders the Scotia Sea while to the south it meets the Antarctic. Its width is on average nine hundred kilometers and its waters are considered by sailors as the most stormy in the world.

Riiser-Larsen Sea

It is a sea considered marginal belonging to the Antarctic Ocean that is located on both sides of the agreed limit that corresponds to the Indian and Atlantic Oceans. Its coordinates range between 68 ° S and 22 ° E.

Its name comes from the Norwegian explorer Hjalmar Riiser-Larsen and it is considered a marginal sea since it does not belong to any specific nation. It covers up to 1,138,300 square kilometers and its average depths exceed 3,000 meters.

During most of the year its waters are full of icebergs. It has a number of coastlines such as the Princess Astrid Coast, the Princess Ragnhild Coast, and the Land of Queen Maud.

Sea of ​​cosmonauts

Like the previous sea, it is a marginal sea of ​​the Antarctic Ocean that joins the South with the Indian Ocean.

Its name comes from a tribute to the first Russian astronauts on behalf of the Soviet Antarctic Expedition. During this journey, navigators decided to separate that territory as an independent sea from Antarctica, in 1962.

The waters of this sea bathe the shores of Prince Harald, Prince Olaf and the Land of Queen Maud; all these lands are owned by Norway.


Characteristics of the ocean floor

The Antarctic Ocean is characterized by being a deep territory with few narrow or shallow areas; Only the Antarctic continental shelf is narrow and has a depth of 800 meters, which makes it the deepest shelf since the world average does not exceed 130 meters.

Most of the ocean floor is covered by sediments of glacial origin that belong to the frozen ground and are transferred over time to the waters.

Antarctic natural resources

Antartic Ocean

The natural resources of the Antarctic have not been worked yet; however, it is believed that there is natural gas and oil fields in its waters. The possibility that it contains manganese nodules is also considered.

As for its ice, Antarctica contains the largest reserve of fresh water in the world due to the fact that 81% of its content lacks salt. In addition, the ocean features a large number of krill communities and various fish specimens.


The temperature of sea waters can vary between 10 ° C and -2 ° C. Likewise, cyclonic storms that advance eastward through turns that develop around the Antarctic continent are common.

These cyclones are of strong intensity and are the reason for the climatic difference between the open ocean and the ice.

The Antarctic ocean surface, which includes the Antarctic Circumpolar Current, contains the strongest winds on the globe.

In addition, in winter the waters freeze completely up to 65 ° S towards the Pacific and up to 55 ° S towards the Atlantic. However, some coasts do not freeze thanks to the constant winds that come from the interior, which keeps the beaches free during winter.

An ice pack forms around Antarctica – a floating ice sheet – that can be up to one meter deep and reaches two million kilometers during March. Its longest length is formed in September as it reaches 18 million square kilometers: it increases in size up to seven times.

The waves in the Antarctic are usually very high and its icebergs reach overwhelming dimensions, which constitutes a notable danger for navigation.

Environmental impact

The Antarctic region is one of the territories most affected by the hole in the ozone layer, which allows the passage of ultraviolet rays through the Earth’s atmosphere.

Some scientists consider that Antarctica is more prone to UV rays due to a drastic decrease of up to 15% of phytoplankton in the ocean. This occurs due to the unregulated and illegal fishing of whales that feed on krill, the main predator of phytoplankton.

To improve the situation, several nations of the world have prohibited mining exploitation in the Antarctic Circumpolar Current, since this activity also negatively modifies the natural course of the climate and ocean winds.


The cold winds of the Antarctic Ocean allow the gestation of a very specific flora in the coastal territories.

These are generally vascular plants that originated during the division of Gondwana; however, lichens and mosses are also common as they are specimens that adapt well to cold.

Antarctic hairy grass ( Deschampsia antarctica )

Antarctic hairy grass, also known as Antarctic grass, is one of the vascular phanerogamic plants that were born in Antarctica. It is characterized by its remarkable resistance to ultraviolet rays thanks to the chemical compounds it uses to synthesize light.

Some scientists believe that this property of the hairy herb could be used in pharmacological research to treat skin and foot cancer. This plant was first described by Étienne-Émile Desvaux in 1854.

Antarctic pearl ( Colobanthus quitensis )

Also known as the Antarctic carnation, it is another of the native species of Antarctica. The Antarctic pearl belongs to the Caryophyllaceae family and is characterized by its yellow flowers. It reaches up to five centimeters in height.

In addition, this plant maintains habits similar to that of mosses and is not only found in Antarctica but can also be found in other regions, even extending to Mexico.


They are organisms that are born from the symbiosis between an alga and a fungus, although they need a third component: a yeast from the Basidiomycota division that has been found in the cortex of most species of lichens. However, scientists still do not know its specific role in the symbiosis process.

They are characterized by being multicellular organisms very resistant to climatic adversities, which allows them to colonize various ecosystems.

Lichens maintain the best of both species: from the fungus they take their protection from solar radiation, while from the algae they acquire the ability to photosynthesize.


The fauna of the Antarctic Ocean is made up mainly of whales, krill and plankton, although it also has some species that live both in the cold lands of Antarctica and in the ocean, such as penguins and seals.

True seals (Phocidae)

It is a family of pinniped mammals that has managed to adapt to live most of the time in aquatic environments.

Of the Phocidae 19 species are known, which are characterized by lacking an auditory pinna and by having hind limbs that are not functional during land movement.

Penguins (Spheniscidae)

They are a family of birds belonging to the Sphenisciformes order. They are flightless seabirds that inhabit the lands of the southern hemisphere, although some species have been found inhabiting the Galapagos Islands.

The first Europeans to visualize these birds were the explorers of Vasco de Gama, who named it “silly birds” due to its clumsy gait and because it was a bird without the ability to fly.

Later the British called them penguins , whose origins in Welsh can be translated as “white head”.

Krill (Euphausiacea)

They are an order of malacostraceous crustaceans popularly known as “krill”. They are found in all the maritime territories of the world and are the main predator of phytoplankton.

In addition, they are considered as a fundamental part of the trophic chain, which is why they maintain the order of ocean ecosystems.

In the Antarctic Ocean, a particular species (Antarctic krill) has been found that forms a biomass of 379,000,000 tons, which makes this species the animal with the highest biomass in the world. For this reason, krill is the main food for species such as squid, fish, seals, penguins, and baleen whales.

Countries with coasts in the Antarctic

The Antarctic Ocean is circumscribed around Antarctica. This means that the only region with coasts in this ocean is Antarctica, along with the islands that are located around this territory.

Below are some of those coastal areas in the Antarctic:

– Antarctica.

– Olson Island.

– Oriental Ongul Island.

– Vollmer Island.

– Scott Island.

– Kizer Island.

– Isla Fisher.

– Inexpressible Island.

– Inaccessible Island.

– Berkner Island.

– Roosevelt Island.

– Ross Island.


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