TORONTO -- National Geographic has announced they are officially recognizing a fifth ocean, known as the Southern Ocean, which encircles Antarctica.

The non-profit organization announced the move on World Oceans Day Tuesday, saying “since National Geographic began making maps in 1915, it has recognized four oceans: the Atlantic, Pacific, Indian and Arctic Oceans starting on June 8… it will recognize the Southern Ocean as the world’s fifth ocean.”

National Geographic Society geographer Alex Tait said in the announcement that the Southern Ocean has “long been recognized” by scientists as forming a “distinct ecological region defined by ocean current and temperatures,” but was never internationally agreed upon as a distinct body of water.

While an official recognition by the relevant international bodies has yet to occur, the International Hydrographic Organization (IHO), have yet to ratify a sea-mapping proposal from 2000 addressing the Southern Ocean, however the U.S. Board of Geographic Names, which has maintained and regulated geographic name usage since the 1800s, has. This marks the first time National Geographic has done so, breaking away from the IHO.

The move makes the Southern Ocean the second smallest in the world, only larger than the Arctic Ocean.