You may have heard experts referring to the ocean in the singular. It’s “the ocean”, as opposed to “the oceans”.
But if there is just one global ocean, what are the 5 oceans that many people reference, and why are 7 seas occasionally mentioned?
It’s confusing, but the answer is not as ambiguous as you might think and, in this guide, we’ll tell you what you need to know and get into some fascinating ocean facts while we are at it.
One Global Ocean
Technically, there is only one world ocean.
The body of water that spans 71% of the earth’s surface is connected, and so it’s basically the liquid equivalent of Pangea, a land mass once formed from all of the world’s continents.
However, this “world ocean” is often divided into four main oceans (Atlantic Ocean, Pacific Ocean, Arctic Ocean, and Indian Ocean) with many countries now recognizing the Southern Ocean as number five on that list.
The boundaries that define these many oceans have changed over the years, and if you go back many centuries, the number of oceans has also changed, with early civilizations creating tighter borders and understanding less about the bodies of water that make up the earth’s surface.
How Many Oceans Are There? Are There 5 or 7 Oceans?
Ancient pirates were said to have “sailed the seven seas”, a phrase that was passed down to us from Ancient Greece and through Medieval Europe.
The seven seas have actually changed over the years.
The Ancient Greeks considered the seven seas to be the Aegean, Mediterranean, Black Sea, Red Sea, Adriatic Sea, Persian Gulf, and the Caspian Sea.
Many hundreds of years later, European sailors described the seven seas as the Baltic, Atlantic Ocean, North Sea, Black Sea, Red Sea, Arabian Sea, and the Mediterranean Sea, several of which were not known to the Greeks.
Following the discovery of the Americas, the concept changed again, but the idea of “7 seas” did not.
Today, there are just 5 recognized oceans: the Atlantic Ocean, Indian Ocean, Arctic Ocean, Pacific Ocean, and the Southern Ocean.
As of June 8, 2021 the Southern Ocean is now recognized as the fifth body of water and is located near Antarctica. You can read more about World Ocean Day and the Southern Ocean at National Geographic.
The idea that there are four oceans present is due to the boundaries that have been set by the International Hydrographic Organization in 2000.
What are the 5 Biggest Oceans in the World?
The five biggest oceans are as follows:
A vast ocean that sits between North and South America to the west and Europe and Africa to the east.
The Pacific Ocean is the largest ocean in the world.
It’s a massive ocean that extends from the Arctic Ocean to the Southern Ocean.
It stretches between Asia and Australia on one side and North and South America on the other.
The Indian Ocean covers the Arabian Sea and Persian Gulf (previously listed as separate seas by our ancestors).
It is located to the west of Australia and covers India, as well.
The Arctic Ocean is a comparatively small ocean located around the North Pole.
Also known as the Antarctic Ocean or the Southern (Antarctic) Ocean, this body of water is the latest to gain official recognition.
According to the US Board on Geographic Names, it extends out from the coast of Antarctica.
However, it has not been recognized by all authorities.
Stats & Facts About the Oceans
Ever wondered which ocean is the biggest, most dangerous, or cleanest? Let’s take a look at the most commonly asked questions about the world’s oceans.
Which Ocean is the Biggest and Deepest?
The Pacific Ocean is both the biggest and deepest of the five oceans, encompassing around half of all the water on the planet and spanning a vast 63 million square miles.
The Challenger Deep is the deepest part of the Pacific Ocean measuring at 6.8488 miles deep, which is located just beneath the western region of the Pacific Ocean.
It’s below sea level and is almost three times deeper than where the Titanic was found, which is 2.4 miles down.
Only three divers have ever reached bottom of the Challenger Deep.
The first-time explorers swam to the area was in 1960, when two divers spent five hours swimming more than six miles down.
More about Challenger Deep from Wikipedia.
The Marianas Trench, located between Guam and the Philippians, is the deepest oceanic trench on Earth and is also located in the pacific.
Which Ocean is the Coldest?
Not only is the Arctic Ocean the smallest ocean in the world, but it’s also the coldest. The Arctic Ocean also has the shallowest water of all the oceans.
The water doesn’t get any direct sunlight because the sun tends to stay low on the horizon, even during the warmer seasons.
The ocean still warms the air because it’s still warmer than the ice that is present.
The average temperature in the Arctic Ocean is 28.8 degrees Fahrenheit. The temperature is consistent year-round and doesn’t fluctuate a lot.
The Arctic polar vortex, a band of strong westerly winds consisting of extremely cold air, encircles the Arctic Ocean and influences the low temperatures in the water.
You can read more about the Arctic polar vortex on Climate.gov.
Which Ocean is the Warmest?
The Pacific Ocean is the hottest of all the world’s oceans, and by quite a long way.
Which Ocean is the Most Dangerous?
It depends on the definition.
If we’re talking about shipwrecks, then it would probably go to the Atlantic Ocean, as it encompasses both the North Sea and the Mediterranean Sea, which are some of the most troubled on the planet.
There have also been many more shark attacks in the Atlantic Ocean than in the Pacific Ocean.
Which Ocean is the Cleanest?
The Southern Ocean is relatively far removed from human involvement and so it’s probably the cleanest of the five oceans.
Which Ocean is the Saltiest?
The Atlantic Ocean is the saltiest of all five ocean basins.
Why Is The Ocean Blue?
The ocean and sea waters absorb colors in the red portion of the light spectrum, filtering out red hues and leaving behind the only colors in the blue spectrum.
What is the world’s oldest ocean?
The Pacific Ocean is the older of today’s oceans.
We know this because scientists have been able to date rocks found in the Pacific Ocean to 200 million years old.
Why Is the Pacific Ocean Called the “Ring of Fire”?
The Pacific Ocean is referred to as “The Ring of Fire” because of the amount and severity of earthquake and volcanic activity that happens where the tectonic plates meet.
How Old Is The Water in the Ocean?
The ocean is about 3.8 billions year old. The ocean was created when the Earth started to cool below 212 degrees Fahrenheit and the gas that was present turned into rain.
You can read more about the ocean at Nature.com.
What Happen When If the Ocean Gets Too Warm?
Among other climate changes that are not fully understood, if the ocean gets too warm the ocean will experience coral bleaching and the loss of breeding grounds for marine fishes and mammals.
You can read more about ocean warming at International Union for Conservation of Nature (IUCN).
What Is The Largest Ocean Wave Ever Surfed?
The largest wave ever surfed measured at 80 feet and was ridden by Rodrigo Koxa back in 2017.
To put that into perspective, it’s roughly the size of four 2-story houses stacked on top of one another.
It was an epic accomplishment for Koxa, and the fact that humans can ride 80-foot waves is an achievement for mankind on the whole.
But it pales in comparison to the biggest wave ever recorded, one that would destroy the best big wave surfers.
What is the Biggest Wave Ever Recorded?
The biggest wave recorded by humans measured at a staggering 1,720 feet.
The giant wave occurred in Lituya Bay, near Alaska, and was the result of a megatsunami.
It began with an earthquake on the Fairweather Fault, located in the heart of Lituya Bay.
The quake triggered a megatsunami that was somewhere between 100 and 300 feet, but the breaking waves that followed were much bigger and eventually peaked at 1,720 feet.
For perspective, the Empire State Building is only 1,250 feet.
There were three fishing boats in Lituya Bay at the time of the wave.
Fishermen in two of these boats actually surfed the wave while two individuals in the third boat lost their lives.
We say “surfed”, but “carried” is probably a better description.
How Was the Giant Wave Measured?
Only a few fishermen witnessed the big wall of water, and they weren’t really in a position to reach for their measuring tape and get to work.
So, how do we know this was actually the tallest tsunami and the biggest wave?
These records come from the landscape, or rather, the damage left behind by the Lituya Bay tsunami.
We know, for instance, that trees were ripped from their roots at elevations of up to 1,720 feet.
In fact, the damage was so severe that millions of trees were uprooted and swept away.
By the same token, we know it wasn’t much bigger because of the lack of damage at higher elevations.
Summary: How Many Oceans are There?
As you can see, there is really only one global ocean if we’re focusing on connected bodies of water and either 4 or 5 if we’re using officially recognized dividers.