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Blockbuster press official announcement!
The fifth ocean of the earth, the Southern Ocean, is coming!
In those years, the geography teacher told us in class that we must remember the names of the seven continents and four oceans, namely:
Asia, Africa, Europe, South America, North America, Australia, Antarctica;
Pacific, Atlantic, Indian, Arctic.
On June 8 of this year, World Oceans Day, the National Geographic Society announced its latest mapping policy, officially recognizing the Southern Ocean!
The history of the Southern Ocean controversy
The history of the Southern Ice Ocean has been debated since ancient times.
In 2000, the International Hydrographic Organization identified a body of water as the Antarctic Sea.
It is the ocean that surrounds Antarctica and is an extension of the Pacific, Indian, and southern Atlantic Oceans.
Some scientists have always believed that the sea area is the Southern Ocean, but many scholars have opposed it - as an ocean, there must first be a mid-ocean ridge, and the Southern Ocean does not meet this basic condition.
In particular, textbooks and maps published in China generally do not recognize and do not mark the Southern Ocean, such as the World Atlas published by China Map Publishing House in 2009.
Whether or not the Southern Ocean should be established as an independent ocean has been debated endlessly, and there is no conclusive conclusion.
(Source Figure Worm)
This particular body of water must have a saying!
The National Geographic Society is one of the most authoritative institutions in the world's geographical community, dedicated to the science, education and dissemination of geographical knowledge.
It operates National Geographic, which has been mapping the oceans since 1915 and has always marked the four oceans.
Until this year's World Oceans Day (June 8), national geographic channel cartographers said that the rapid ocean currents around Antarctica make the waters there unique and deserve their own name, the Southern Ocean.
At this point, the authority recognized the Southern Ocean as the fifth ocean of the earth!
(Source: NASA/JPL; Green Marble）
The Southern Ocean is the only one that comes into contact with the other three oceans and embraces one continent completely, rather than being embraced by the continents.
So why did the Southern Ocean come out alone?
What is unique about it?
1. The most important basis for division - ocean currents
Other oceans are divided by the continents that surround them, while the Southern Ocean is divided by ocean currents.
Scientists estimate that the Antarctic Circumpolar Current –ACC was established about 34 million years ago, when Antarctica separated from South America.
This allows water to flow unimpeded at the bottom of the earth.
The ACC flows from west to east around Antarctica, forming a broad band of fluctuations centered roughly at 60 degrees south latitude, a line now defined as the northern boundary of the Southern Ocean.
Inside the ACC, the seawater is colder and has a slightly lower salt content than the northern seawater.
Extending from the surface to the seafloor, the ACC transports more water than any other ocean current.
It absorbs the waters of the Atlantic, Pacific and Indian Oceans, helping to drive a global circulatory system known as a "conveyor belt" that transfers heat around the Earth.
The cold, dense water that sinks to the bottom of antarctica also helps store carbon in the deep ocean. The southern ocean therefore has a crucial impact on the Earth's climate.
Scientists are currently studying how human-induced climate change is altering the Southern Ocean.
Scientists have learned that the seawater flowing through the ACC is warming, but it's unclear how much this will affect Antarctica.
The rapid melting of some continental ice sheets and ice shelves occurs closest to land in the ACC.
2. The ecology of the Southern Ocean is unique
In the unique waters of the Southern Ocean, thousands of creatures live. National Geographic explorer Enrique Sara points out that the Southern Ocean has a unique and fragile marine ecosystem that is home to marine life such as whales, penguins and seals.
More importantly, the Southern Ocean also has an impact on the ecology of other regions. For example, humpback whales feed on krill near the South Pole and then migrate northward to spend the winter in different ecosystems in the Americas, and some seabirds come in and out.
(Source: Figureworm)
So what exactly are the boundaries of the Southern Ocean?
National Geographic has now identified the five oceans of the world.
With the exception of the Drake Passage and the Scotia Sea, most of the waters within 60 degrees south latitude of the Antarctic Circle make up the newly recognized Southern Ocean.
The currents surrounding Antarctica only began to appear thirty million years ago when Antarctica and South America separated, so the Southern Ocean was a very young ocean.
The confluence of the Antarctic Ocean Current and the warm waters of the North is the natural boundary of the Southern Ocean. The Antarctic Current is maintained at around 60 degrees south latitude in southern New Zealand, and in the Atlantic ocean, due to the strong westerly wind belt, it can reach 48 degrees south latitude.
（来源: NASA/JPL; International Hydrographic Organization (IHO)）
Once the Southern Ocean was controversial
A new map policy
Finally bringing the Southern Ocean into our world
Since then, the fifth ocean of the earth, the Southern Ocean, has come!
National Geographic
https://www.nationalgeographic.com/
“There's a New Ocean Now”. National Geographic Society. [2021-06-08].
https://www.nationalgeographic.com/environment/article/theres-a-new-ocean-now-can-you-name-all-five-southern-ocean
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Editor: Du Xinyu
Proofreader: Tao Qin Liu Qijun
Author: Wu Jinjian
Source: Institute of Geology and Geosciences, Chinese Academy of Sciences
Source: Institute of Geology and Geosciences, Chinese Academy of Sciences