To commenorate World Oceans Day, National Geographic announced Tuesday, that it is officially recognizing the Southern Ocean as the Earth’s fifth ocean.
Even though the National Geographic Society has been making maps since 1915, up until yesterday, only four oceans, the Atlantic, Pacific, Indian, and Arctic Oceans were officially recognized. The Southern Ocean is now the fifth ocean on the list.
Geologically, the Southern Ocean is the youngest of all the oceans, forming about 30 million years ago when Antarctica and South America moved apart, forming the Drake Passage.
The separation of the two continents allowed for the formation of the Antarctic Circumpolar Current (ACC). And it is the ACC that gives the Southern Ocean its very own uniqueness.
Deliniating the boundries of the Southern Ocean
Unlike the rest of the world’s oceans, the Southern Ocean’s boundaries are not defined by any landmasses. Instead, it is the current that lies within it that defines its boundary.
Specifically, the Southern Ocean is comprised of most of the waters that surround the continent of Antarctica out to 60 degrees south latitude, apart from the Drake Passage and the Scotia Sea.
For a long time, it wasn’t certain if whether the body of water was unique enough to be given its own official name, or whether it should just be considered a southern extension of the Atlantic, Pacific, and Indian Oceans.
The ACC, flows from west to east around the southern continent, forming an ocean that is colder and slightly less salty than the waters surrounding it to the north, And this circulation plays a key role in the Earth’s changing climate.
The ACC helps to keep Antarctica cold and ecologically distinct, making the ocean home to thousands of species that are found nowhere else on Earth, according to Newsweek.
And here’s another little-known fact about the ACC – It is the Earth’s only global current that uses waters from the Atlanta, Pacific and Indian Oceans to transport heat around the planet.
As described in National Geographic by NOAA marine scientist Seth Sykora-Bodie, the Southern Ocean is unique in that “the glaciers are bluer, the air colder, the mountains more intimidating and the landscapes more captivating than anywhere else you can go.”
The National Oceanic and Atmospheric Administration (NOAA) also recognized the Southern Ocean’s designation earlier this year, and the U.S. Board on Geographic Names has recognized the ocean since 1999.
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