4 or 5: how many oceans are there on Earth, and why their number is changing

When most of us went to school, then on the geographical maps of our planet 4 oceans were indicated: Atlantic, Pacific, Indian and Arctic. But on modern maps you can see the name of the 5th ocean - the South. What kind of ocean is this, and why did it become necessary to rewrite maps and change the number of available oceans?

The confusion with the oceans continues for more than a century. For the first time, the term "Southern Ocean" is found on maps of the 17th century and refers to the expanses of the ocean surrounding the "Unknown Southern Continent", which was not yet open at that time, the existence of which travelers suspected. The southern parts of the Atlantic, Indian and Pacific oceans differed greatly in terms of navigation: there were currents, strong winds and floating ice. For this reason, this region is sometimes isolated in a separate ocean, and in some cartographic materials of the XVII-XVIII centuries you can see the names "Southern Ocean", "Arctic Ocean". Later the name "Antarctic Ocean" began to be found.

After the discovery of Antarctica, in the middle of the 19th century, the Royal Geographical Society in London designated the borders of the Southern Ocean, referring to it the southern parts of the Pacific, Indian and Atlantic oceans, which are located between the southern polar circle and Antarctica. And the International Hydrographic Organization approved the existence of the Southern Ocean by 1937.

But later, scientists again came to the conclusion that the allocation of the Southern Ocean was impractical, and it again became part of the three oceans, and by the middle of the 20th century this name was no longer found on sea charts or in school textbooks.

The need to highlight the Southern Ocean was again discussed at the end of the 20th century. The waters of the three oceans surrounding Antarctica differ in many respects from the rest of the oceans. A powerful circumpolar current passes here, the species composition of the marine fauna is very different from warmer latitudes, and floating ice and icebergs are found everywhere around Antarctica. We can say that the Southern Ocean was distinguished by analogy with the Arctic: too different environmental conditions in the polar and polar regions of the ocean and in other parts of the World Ocean.

Members of the International Hydrographic Organization in 2000 decided to separate the Southern Ocean, and its northern border was drawn along 60 parallels of the southern latitude. Since then, this name appears on the maps of the world, and on our planet again 5 oceans.