While there is one global interconnected ocean, this massive body of water surrounding all land masses on Earth can be further subdivided based on historical, geographic, and cultural factors.
Oceans cover much of the Earth’s surface. About 71% of the Earth’s surface is covered by oceans and 97% of all the water found on Earth is in the ocean. To put it in numbers, 321,003,271 cubic miles of water are found in the ocean, which according to NOAA, can fill about 352,670,000,000,000,000,000 gallon-sized milk containers.
Why are Oceans Important?
Aside from being a huge body of water, oceans are important to the health of the Earth for many reasons. Oceans produce half of the oxygen that reaches the atmosphere and are a carbon sink, absorbing massive amounts of carbon dioxide. In other words, the world’s oceans are a huge carbon reservoir, hold more than 50 times the carbon dioxide compared to the atmosphere.
Oceans also move heat around the world, helping to regulate the world’s climate.
The Number of Oceans Depends on How You Count Them
The number of oceans in the world depends on the perspective. The designation of the world’s oceans has evolved over time.
One Global Ocean
There is one global ocean. All ocean waters are connected.
The world ocean holds most of the water in the Earth’s systems. This part of the Earth’s systems is known as the hydrosphere. More: Water on Earth
Are There 3, 4, or 5 Oceans in the World?
On Earth, there are three major oceans: the Pacific, Atlantic, and Indian oceans.
Historically, there are four ocean basins that include the three major oceans (Pacific, Atlantic, and Indian) and the Arctic Ocean. There are five oceans if you also include the Southern Ocean as a separate ocean.
The Southern Ocean is a fairly recently named addition (2000) that is not universally recognized by all countries and organizations and has yet to be ratified by the international community.
For example, the U.S. Board on Geographic Names recognizes the Southern Ocean while National Geographic does not.
The video below explains the names and boundaries of the world’s oceans based on one global ocean, the three major oceans, the four historic oceans, and the five world oceans.
The Five World Oceans
Each of the five world oceans are described here including the size of each ocean as well as a map showing the location and boundaries for each ocean.
Facts About the Pacific Ocean
The Pacific Ocean is the world’s largest ocean. It spans from the Arctic Ocean in the north to the Southern Ocean in the south.
How Big is the Pacific Ocean?
The Pacific Ocean is 165,250,000 square km (63,800,000 sq. mi) in area and covers 46% of Earth’s water surface.
The Pacific Ocean covers 28% of the global surface which is roughly equivalent to all of the landmasses combined.
What is the Deepest Point in the Pacific Ocean?
The deepest point on Earth, the Mariana Trench, is located in the Pacific Ocean.
Seas and Gulfs of the Pacific Ocean
Where is the Pacific Ocean Located?
The Pacific Ocean is found along the western coast of the United States, along Southeast Asia, the eastern side of Australia, and along the western coast of South America.
Facts About the Atlantic Ocean
The Atlantic Ocean is the second largest ocean in the World. This body of water is located between Africa, Europe, the Arctic Ocean, the Americas, and the Southern Ocean.
How Big is the Atlantic Ocean?
The area of the Atlantic Ocean is about 106,460,000 square km (41,100,000 sq mi).
Deepest Point in the Atlantic Ocean
The lowest point in the Atlantic Ocean is the Milwaukee Deep in the Puerto Rico Trench with a depth of 8,376 m (27,480 ft).
Seas and Gulfs of the Atlantic Ocean
The Atlantic Ocean includes the Baltic Sea, Black Sea, Caribbean Sea, Davis Strait, Denmark Strait, part of the Drake Passage, Gulf of Mexico, Labrador Sea, Mediterranean Sea, North Sea, Norwegian Sea, almost all of the Scotia Sea, and other tributary water bodies.
Where is the Atlantic Ocean Located?
The Atlantic Ocean is found along the eastern coast of the United States, the eastern coast of South America, the western coast of Africa, and north and western Europe.
Facts About the Indian Ocean
The Indian Ocean is the third largest ocean. This body of water stretches between Africa, the Southern Ocean, Asia, and Australia.
How Big is the Indian Ocean?
The area of the Indian Ocean is 70,560,000 sq km (27,240,000 sq mi) which represents 19.8% of the water on Earth’s surface.
The Deepest Spot in the Indian Ocean
The deepest spot in the Indian Ocean is in the Java Trench that is located south of Java in the eastern Indian Ocean and is 25,344 feet (7,725 meters) deep.
What Seas and Gulfs are included in the Indian Ocean?
The Indian Ocean includes includes Andaman Sea, Arabian Sea, Bay of Bengal, Flores Sea, Great Australian Bight, Gulf of Aden, Gulf of Oman, Java Sea, Mozambique Channel, Persian Gulf, Red Sea, Savu Sea, Strait of Malacca, Timor Sea, and other tributary water bodies.
Where is the Indian Ocean Found?
The Indian Ocean is found along the eastern coast of Africa, the Middle East, the southern part of Asia, and the western coast of Australia.
Facts About the Arctic Ocean
The Arctic Ocean is the smallest ocean in the world.
How Big is the Arctic Ocean?
The area of the Arctic Ocean is 14,056,000 sq km (5,427,000 sq mi) which makes it the only ocean smaller than Russia.
The Arctic Ocean is the Coldest Ocean
This ocean is also the coldest of the world’s oceans.
Where is the Arctic Ocean Located?
Seas and Gulfs of the Arctic Ocean
Facts About the Southern Ocean
The Southern Ocean (also referred to as the Antarctic Ocean) is a proposed ocean surrounding Antarctica with a northern limit of 60°S latitude. The northern boundary abuts the Atlantic, Indian and Pacific Oceans, making it the only ocean not to have a land mass as the border.
What makes some organizations designate the Southern Ocean as the world’s fifth ocean is the fact that its waters differ from other oceans due to fairly rapid circulation.
How Big is the Southern Ocean?
It is the second smallest of the five world oceans. It has an area of 20.327 million sq km (7.849 million sq mi).
Seas of the Southern Ocean
The Southern Ocean includes Amundsen Sea, Bellingshausen Sea, part of the Drake Passage, Ross Sea, a small part of the Scotia Sea, Weddell Sea, and other tributary water bodies.
How are the Ocean Borders and Names Determined?
The International Hydrographic Organization (IHO), which first convened in 1919 (and was originally referred to as the International Hydrographic Bureau (IHB)), is the inter-governmental organization that creates the international agreement of ocean borders and names.
The outcomes of each convention are published in the Limits of Oceans and Seas.
Watch: How many oceans are there?
What are the seven seas?
The Sevens Seas is a historic term naming the dominant trade routes and regional bodies of the world’s oceans. The concept of the Seven Seas can be traced back to approximately 2,300 BCE, specifically in Hymn 8 of the Sumerian text authored by Enheduanna in honor of the goddess Inanna (Meador, 2001).
The ancient Greeks identified and named seven significant bodies of water that were known to them at the time: the Aegean Sea, Adriatic Sea, Mediterranean Sea, Black Sea, Red Sea, Caspian Sea, and the Persian Gulf.
From a modern perspective, the Seven Seas are the five world oceans plus splitting the Atlantic Ocean and Pacific Ocean into north and south regions: the North Atlantic, South Atlantic, North Pacific, South Pacific, Arctic, Indian and Southern Oceans.
References
IHO (International Hydrographic Organization), 2000. Report of the International Hydrographic Organisation. Working Paper No. 57 (WP 57). 20th Session of the United Nations Group of Experts on Geographical Names, (New York), 17–28 January 2000.
