Southern Ocean is the fourth largest of the five oceans in the world. It can be considered as the most debated ocean in terms of its boundaries. Even today there is no boundary for Southern Ocean that all the countries of the world follow. Let’s learn about some cool Southern Ocean facts which has several names like Antarctic Ocean, Great Southern Ocean, South Polar Ocean and Austral Ocean. Let’s begin…
Southern Ocean Facts: 1-5 | Definitions of Southern Ocean
1. Cartographers and explorers started defining the Southern Ocean in their own terms. Vasco Núñez de Balboa actually named Pacific Ocean as the Southern Ocean because he approached the ocean from north. Later other explorers and authors used this term to the waters which surrounded the Antarctica continent.
2. Most of the navigators differed in their view of the extent of this ocean. As per James Cook, New Caledonia bordered the Southern Ocean. In the year 1796, John Payne gave 40oS (40 degrees South) as the northern limit of the ocean.
3. Precursor of International Hydrographic Organization (IHO – an intergovernmental organization that surveys and charters the water bodies of the world), the International Hydrographic Bureau (IHB) published Limits of Oceans and Seas in 1928.
4. In this publication, they delineated the ocean basing on the land limits. To the south of this ocean was Antarctica and to the north were Africa, Australia, South America and New Zealand’s Broughton Island.
5. In 1937 second edition of Limits of Oceans and Seas was published according to which the boundary of the ocean changed again. The boundary was moved towards the south side. From Africa (Cape Agulhas) to Australia (Cape Leeuwin), the boundary was at 40oS. And from New Zealand (Auckland island) to South America (Cape Horn), the boundary was at 55oS.
Southern Ocean Facts: 6-10 | Definitions of Southern Ocean
6. In the year 1953, the Southern Ocean didn’t appear in the maps of the third edition of Limits of Oceans and Seas. The place of the Southern Ocean was taken up by Indian Ocean, Pacific Ocean and to an extent, the Atlantic Ocean.
7. In 2002, IHO conducted a survey related to the Southern Ocean and published another edition of Limits of Oceans and Seas. Of the 68 nations who are the members of IHO, only 28 responded. 27-member nations agreed for the redefinition of the ocean. The only responding nation which opposed to any redefinition was Argentina.
8. 18 votes went to the name Southern Ocean. However, the boundary of the ocean was still unresolved. According to the IHO, the northern limit of the Southern Ocean is at 60oS but many consider it to reach till 50oS while some other countries or organizations go for 35oS as Southern ocean’s limit. However, 2002’s edition is not approved till now.
9. Some agencies like USA’s CIA, Merriam-Webster etc. uses the northern limits given by the IHO. But other organizations like Encyclopedia Britannica uses Antarctic Convergence (a curve which encircles the Antarctica continent with changes in latitudes as per the seasons).
10. Likely in Australia, cartographers consider that Southern Ocean starts from the water body posterior to the Australia and New Zealand. National Geographic Society maps stills shows the Atlantic Ocean, Indian Ocean and Pacific Ocean extended to the south region.
Southern Ocean Facts: 11-15 | History of Southern Ocean
11. Terra Australis, a continent which was believed to exist in the south to balance the continents of the north, fascinated the cartographers and navigators alike. In 1487, Bartolomeo Diaz sailed around the Cape of Good Hope. This made the explorers realize that Africa is separated from the Antarctic land or Terra Australis by a large water body.
12. Gabriel de Castilla of Spain was the first person to be credited for the discovery of the Antarctic continent. He just saw snow covered mountains. His words were not taken seriously then.
13. The desire to find the big continent lead to many explorations and in turn led to many discoveries of islands like Roché Island, Bouvet Island etc. It was only in 1770 that the explorers reached the Antarctic Circle.
14. Many other explorers tried their luck but all their attempts went in vain. On February 19, 1819 William Smith, an Englishman, sighted the Livingston Island. He later discovered other islands of South Shetlands etc.
15. Later many expeditions were done by America and other nations who sailed through Antarctic Ocean or Southern Ocean and reached Antarctica continent.
Southern Ocean Facts: 16-20 | Geography of Southern Ocean
16. Did you know that the Southern Ocean, geologically, is the youngest of all oceans? It was formed when South America and Antarctica moved apart creating Drake passage. It happened 30 million years ago.
17. One feature that differentiates Southern Ocean from other oceans is that its boundary is not set by any landmass. Its northern boundary is marked by Indian, Atlantic and Pacific Oceans.
18. Water of Southern Ocean is different from that of the other oceans. Due to the Antarctic Circumpolar Current (moves clockwise that is from west to east), water gets transported quickly around Antarctica. Water south to New Zealand resembles with the water south of South America, but not Pacific Ocean.
19. The average depth of the Southern Ocean is between 4,000-5,000 meters or 13,000-16,000 feet. But it has some shallow regions. South Sandwich Trench’s southern end is the deepest part of the Southern Ocean. It has a depth of 7,236 meters or 23,740 feet.
20. The continental shelf of Antarctica or Antarctica continental shelf is deep with a depth of 800 meters at its edges whereas the average depth of continental shelves of other continents is around 136 meters or 436 feet.
Southern Ocean Facts: 21-25 | Geography of Southern Ocean
21. The ice pack of Antarctic is around 2.6 million square kilometers or 1×106 square miles in the month of March. It increases more than seven times in the month of September and it attains an area of 18.8 million square kilometers or 7.3×106 square miles.
22. There are many seas in Southern Ocean like Weddell Sea, Cooperation Sea, Riiser-Larsen Sea, Lazarev Sea, Cosmonauts Sea, Somov Sea etc. (according to the 2002 draft of IHO). Some seas like Cosmonauts Sea, Somov Sea and Cooperation Sea feature in Russian issued atlases but not in America and Britain issued atlases.
23. Southern Ocean may have huge deposits of oil and gas fields on continental margin. Valuable minerals like gold may also be available there. The icebergs formed in the Southern Ocean can quench the thirst of the world for several months. But no successful attempt has been made to make it a reality.
24. Icebergs may help in future, but as of now they are a major threat to sailors and ships just like the icebergs of Arctic Ocean. The 40oS is known as Roaring Forties, 50oS is known as Furious Fifties, 60oS is known as Shrieking Sixties. These latitudes are so called because of the extremely powerful winds which help in forming big waves which maintain their ferocity thanks to the absence of any landmass. Icebergs make the scenario scarier.
25. There are many major harbors and ports like Rothera Station, Villa Las Estrellas, Mawson Station etc. Most of these stations are under the control of government. McMurdo Station is the southernmost station of the Southern Ocean.
Southern Ocean Facts: 26-30 | Oceanography and Climate of Southern Ocean
26. Antarctic Circumpolar Current is the longest water current in the world. It transports nearly 130 million cubic meters per second of water, which is approximately 100 times the flow of the all the rivers of the world.
27. The water below the ice is cold, extremely dense and highly saline. Then, there are subantarctic waters which are relatively warm. The meeting point of these two different types of water is Antarctic Convergence. Usually Antarctic waters is seen below the subantarctic waters.
28. Upwelling (phenomenon where dense and nutrient rich water moves upwards due to heavy winds thereby replacing less nutritious surface water) is a usual phenomenon in the Southern Ocean. Because of the absence of the landmasses upwelling happens in large scale.
29. Two gyres (system of circulating water currents accompanied by heavy movements of winds) are present in the Southern Ocean. They are Ross gyre in Ross Sea and Weddell gyre in Weddell Sea. They rotate clockwise and are formed by the interactions of Antarctic Convergence and Antarctic Circumpolar Current.
30. The temperatures there varies from −2°C to 10°C or 28°F to 50°F. Storms are intense because of the temperature difference.
Southern Ocean Facts: 31-35 | Lifeform and Environment of Southern Ocean
31. Though the Southern Ocean may look inhabitable, it boasts variety of flora and fauna life. Animals like penguins, orcas, fur seals, Weddell seals, colossal squids, leopard seals, whales etc. are seen in and around Southern Ocean. There are many species of penguins like Rockhopper penguin, Emperor penguin, King penguin, Chinstrap penguin etc. that are found around Southern Ocean. They all breed in the Antarctic.
32. The keystone species (A species which has higher influence on the environment and is extremely crucial in maintaining the ecosystem. This occurs mostly because of the abundance of the species) in the Southern Ocean is the Antarctic Krill. They serve as food to many organisms living in Southern Ocean.
33. There are many organisms which are present in benthic zones (lowest level of the water body). There are as many as 155,000 animals found in Southern Ocean in one square meter. Deep-sea gigantism (Tendency of the benthic animals to be larger than the related species of shallow waters. It is also known as abyssal gigantism) is usually seen among these benthic animals.
34. There are many species of birds like petrels, skuas, albatrosses, gulls, terns etc. South Georgia pipit is an endemic species (species which is found only in one place and nowhere else).
35. There are few fish species in the Southern Ocean. Snailfish, cod icefish, eelpout species make up 9/10th of 320+ fish species present in the Southern Ocean. The specialty of the icefish (only some families of icefish) is that they have antifreeze proteins in their blood. This is why they can live in such cold temperatures. Another group of fish of the genus Notothenia also has antifreeze proteins.
Southern Ocean Facts: 36-40 | Lifeform and Environment of Southern Ocean
36. There are seven pinniped (seal) species present in Antarctica. The largest is the Elephant seal and the smallest is the Fur seal. These two are present north of sea ice. The rest four species, Leopard seals, Weddell seals, Ross seals, Crabeater seals are present on the sea ice. Ross and Leopard seals live solitary lives. The four species make up for the 50% of the biomass of the seals in the world. There are 10 cetacean (whale) species – 6 baleen and 4 toothed whales.
37. Many crustaceans and five species of krill are present in Southern Ocean. The Antarctic krill reverts back to its juvenile stage by using its own body for the necessary nutrients during the winters. Sea spiders (which can grow really big) are also usually found in Southern Ocean.
38. There are many mollusks present in the Southern Ocean especially of the class Bivalve, Cephalopoda etc. The colossal squid belongs to the Cephalopoda. The colossal squid is the food for albatrosses, whales etc. Also, sea urchins, two species of salps and sponges are found in Southern Ocean.
39. The ozone hole not only has reduced the productivity of the phytoplankton by nearly 15% but also has altered the DNA of the species of some fish. Unregulated fishing is also another major environmental concern.
40. International Whaling Commission’s Southern Ocean Whale Sanctuary forbids the commercial whaling (hunting whales for scientific purposes) south of 40 degrees South latitude. Convention for the Conservation of Antarctic Marine Living Resources or CCAMLR, a part of Antarctic Treaty System, tries to preserve the marine life and balance of the ecosystem in the Southern Ocean. This convention came into force on 7 April 1982. Explorations of mineral resources is also prohibited south of Antarctic Convergence.
Southern Ocean Facts: 41-45 | Fun Facts
41. Antarctica is the windiest, coldest and driest continents of the world, thanks to Southern Ocean. 90% of the ice all over the world is present in the Southern Ocean.
42. In Antarctica, summer season is from October to February and winter season is from March to September.
43. The first baby to be born on Antarctica was Emilio Marcos de Palma. He was born on 7 January, 1978.
44. It is often believed that if the ice sheets present in the Southern Ocean melt, the sea level will increase by 65 meters.
45. The Antarctic Treaty System (ATS) was signed on 1 December, 1959 and came into effect on 23 June, 1961. This system limits the military activity near the Southern Ocean and Antarctica. ATS also manages the krill fishery and controls the fish trade.
Southern Ocean Facts: 46-50 | Fun Facts
46. Countries like Argentina, Britain, Spain etc. claim some islands of Southern Ocean as theirs.
47. The coldest temperature ever recorded was in Antarctica. The temperature was -128.6 degrees Fahrenheit.
48. Nearly 50,000 tourists tour the Southern Ocean and Antarctica all around the year.
49. If you just didn’t know, South Pole is surrounded by the Southern Ocean.
50. Yacht races like Volvo Ocean Race, Jules Verne Trophy etc. were held in the Southern Ocean.