1, 4, or 5 Oceans?
How many oceans are there in the world?
While some countries claim that there are four oceans in the world, most agree that there are five:
- Pacific Ocean
- Atlantic Ocean
- Indian Ocean
- Antarctic Ocean
- Southern Ocean
But it isn’t obvious just by looking at a map where one ocean ends and another begins. The truth is that they’re all one connected body of water, and this body of water is sometimes referred to as the global ocean. 71% of the Earth is covered in water, and the different oceans that make up so much of the planet are all unique.
It is only recently that most of the world agreed to recognize five world oceans. The five oceans we now commonly speak of do have official boundaries that have been set by the International Hydrographic Organization. These boundaries are mostly static and based on continental boundaries as well as latitude and longitude lines, but the currents, wildlife, and weather patterns in the world’s oceans are constantly changing.
The Pacific is the world’s largest and deepest ocean. Named by Portuguese explorer Ferdinand Magellan in 1502, it borders the continents of Asia and Australia to the west and the Americas to the east. The explorer decided on the name, which means peaceful, after sailing through a calm patch of the ocean, but this isn’t the most accurate description — the Pacific Ocean is home to violent hurricanes, the Mariana Trench, and many earthquakes. There are sometimes references to the North and South Pacific Oceans.
The name of this ocean comes from Greek mythology and means “Sea of Atlas.” It covers one fifth of the Earth’s surface and separates the American continents from Europe and Africa. The shape of this ocean makes it unique from the others — it is much longer than it is wide, and it takes on an “S” shape. It is sometimes divided into the North and South Atlantic Oceans.
This ocean sits beneath the Asian continent, in between Africa to the west and Australia to the east. The southern limit of the Indian Ocean isn’t widely agreed upon; some authorities state that the ocean extends to the coast of Antarctica, while others define its southern border as latitude 60°S. There is a wide variety of coastal environments to be found around this ocean, among which is the world’s most tectonically active in southern Pakistan.
The world’s smallest ocean, the Arctic Ocean is centered around the North Pole and is home to freezing waters and hostile weather patterns. This is also the ocean that may be most likely to experience severe changes due to climate change because of the large amounts of ice cover found in the area. This ocean is considered to be less scientifically understood than the others because of its remote location and inhospitable climate.
The above map of the world oceans lists only four different oceans. This is how most maps described the world’s bodies of water until the year 1999. The Southern Ocean is not labeled.
The Southern Ocean
In 1999, the National Geography Society officially recognized the Southern Ocean, though it is not yet recognized by all countries. There are several characteristics that make this ocean unique from the other four. One of these is that it is the only ocean whose borders are defined by currents rather than continents. Another is that it is the only ocean that completely surrounds one continent. The borders of this ocean are described by the latitude 60°S.
In addition to being the most recently named ocean, the Southern Ocean is the youngest on the planet in terms of geology. It was formed roughly 30 million years ago when the continents of South America and Antarctica drifted apart. This separation created the Drake Passage and allowed for the Antarctic Circumpolar Current (ACC) to flow around Antarctica in a clockwise motion.
The above map shows the most widely accepted modern representation of the world’s oceans, including the Southern Ocean surrounding Antarctica.
History of Oceans
The oceans of the world formed billions of years ago. The majority of scientists think that water formed on the planet as it cooled, allowing gasses to condense into liquid which filled the Earth’s basins with water. This process likely took centuries, meaning hundreds of years of rain while the global ocean formed.
New theories about the history of the Earth propose the idea that the planet was once actually completely covered with water. This is a relatively new theory, and it’s bringing up new questions about theories regarding the origins of life on the planet.
What are the Seven Seas?
This phrase can be found in literature from several different societies and dates back to thousands of years ago. At various times throughout history it was descriptive of specific bodies of water in different regions of the planet, but the origin of the phrase is not known.
The seven seas are now sometimes defined as the seven oceanic bodies that come from separating two of the world’s oceans into a northern and southern part. However, it’s more common for the phrase to be used as a figurative term to refer to all of the seas in the world.
The modern seven seas:
- Arctic Ocean
- Indian Ocean
- Southern Oceans
- North Atlantic
- South Atlantic
- North Pacific
- South Pacific
The seven seas according to Greek literature:
- Aegean Sea
- Adriatic Sea
- Mediterranean Sea
- Black Sea
- Red Sea
- Caspian Sea
- Persian Gulf
The seven seas according to Medieval European literature:
- North Sea
- Baltic Sea
- Mediterranean Sea
- Black Sea
- Red Sea
- Arabian Sea