The Southern Ocean: The Fifth and Newest Ocean in the World

The Newest Ocean – The Southern Ocean is the world’s youngest named ocean. It was officially recognized in 2000 by the International Hydrographic Organization, making it the fifth major ocean.

Where It Is – The Southern Ocean is located around Antarctica, extending from the coast of the continent northward to the Antarctic Convergence, where cold Antarctic waters meet the warmer waters of the Atlantic, Pacific, and Indian Oceans.

A Circle of Water – Unlike other oceans, which are hemmed in by continents, the Southern Ocean forms a complete ring around Antarctica.

Where Oceans Collide – Its northern edge is defined not by land, but by the Antarctic Convergence, where icy southern waters dive beneath the warmer waters of the Atlantic, Indian, and Pacific.

A Giant in Size – Covering about 20 million square kilometers, it is the fourth-largest ocean—bigger than the Arctic, but smaller than the Pacific, Atlantic, and Indian Oceans.

Deep and Mysterious – The Southern Ocean averages more than 4,000 meters deep. Its lowest point lies in the South Sandwich Trench, which plunges to about 7,400 meters.

The Southern Ocean surrounds Antarctica, bordering the Pacific, Atlantic, and Indian Oceans

The World’s Strongest Current – The Antarctic Circumpolar Current races eastward around Antarctica, moving more water than any other current and linking the Atlantic, Pacific, and Indian Oceans.

Earth’s Climate Engine – Acting like a massive regulator, the Southern Ocean absorbs heat and carbon dioxide, helping to stabilize the planet’s climate.

Sea Ice on the Move – Each year, its sea ice grows and shrinks dramatically—from around 4 million km² in summer to nearly 20 million km² in winter.

Birthplace of Icebergs – Vast tabular icebergs, some over 100 km long, break off from Antarctic ice shelves and drift into the Southern Ocean.

Life in the Cold – From tiny krill to giant whales, from penguins to fish with antifreeze proteins in their blood, the Southern Ocean is alive with species uniquely adapted to the cold.

Krill: The Unsung Giants – Antarctic krill, no bigger than a paperclip, exist in such numbers that their total weight rivals that of all the world’s humans combined.

The Stormiest Seas – The Southern Ocean is infamous for colossal waves and fierce winds, especially in the “Roaring Forties” and “Furious Fifties.”

Rich but Protected – While fishing for species like krill and Patagonian toothfish is carefully managed, mining is banned under the Antarctic Treaty to protect this fragile region.

A Living Laboratory – Scientists from around the world study the Southern Ocean to better understand ocean circulation, climate change, and Antarctic ecosystems.

A Global Carbon Sponge – This ocean soaks up about 40% of all the carbon dioxide absorbed by the world’s seas, making it one of Earth’s most important natural defenses against climate change.