How Many Oceans Are There In The World?

We live on a magnificent planet, especially considering how much water it contains. After all, the ocean provides a wide range of benefits to our planet and all its inhabitants. You may not know that the ocean makes over half of the world’s oxygen. It also absorbs about fifty times more carbon dioxide than our atmosphere does. 70% of our planet is covered by ocean, which means we have more ocean than land!

Although much has been discovered about our oceans, much remains unknown. So, how many oceans are there in the world? It might surprise you to learn that there are more than you thought.

How Many Oceans Are There In The World?

There is really only one ocean in the world, technically speaking. According to the National Oceanic and Atmospheric Administration (NOAA), there is only one global ocean. Geographical mapping and political arrangements, however, have resulted in the official recognition of five oceans. These five oceans are named the Pacific Ocean, Atlantic Ocean, Indian Ocean, Arctic Ocean, and the Southern Ocean. It is interesting to note how each of these oceans is different in terms of its biodiversity, topography, and other characteristics. The oceans are home to an abundance of plant and animal life. A unique ecosystem defines each ocean’s marine life.

Although we have five oceans now, there were only four oceans historically. They were the Atlantic, the Pacific, the Indian, and the Arctic. Recent recognition of the Southern Ocean as an ocean has changed this. What is the history behind the recognition of the Southern Ocean as an ocean? We’ll find out next!

When & Why Did the Southern Ocean Become An Ocean?

Approximately 30 million years ago, Antarctica and South America moved apart, opening the Drake Passage and forming the Southern Ocean. In 2000, the International Hydrographic Organization (IHO), which oversees the naming of bodies of water worldwide, added the Southern Ocean to its list. Following this, the National Geographic Society began to recognize the Southern Ocean around Antarctica in 2021.

As opposed to the other four oceans, the Southern Ocean is not defined by the continents surrounding it. Instead, it is defined by the Antarctic Circumpolar Current (ACC) flowing from west to east, which is a main feature of the Antarctic region. ACC waters, as well as the vast majority of the Southern Ocean, are colder and less salty than the waters to the north. It was only because of these distinctions that the Southern Ocean was able to differentiate itself from others. As a result, it was officially designated as the fifth ocean.

In light of the addition of the fifth ocean, what truly sets each ocean apart from the others? Let’s examine each of the 5 oceans in detail and discover their unique characteristics.

The 5 Oceans & What Makes Them Different From Each Other

As we mentioned earlier, although the ocean is considered to be one body of water, it is divided into five distinct areas. In addition to their names, each of these oceans has its unique environment as well as a unique climate. Let’s break down the five oceans:

Pacific Ocean

One of the largest oceans on earth is the Pacific Ocean. Approximately one-third of the planet’s surface is covered by the Pacific Ocean. It occupies an area bigger than all the continents combined. The Pacific Ocean is so large that 60% of all fish in the world come from it.  The Pacific Ocean is a haven for a wide variety of fish, including tuna, salmon, and snapper. Most of the world’s islands are also found in the Pacific Ocean, including Hawaii! It is estimated that there are over 25,000 islands in the Pacific Ocean. As well as being the largest ocean in the world, it is also the deepest one. The Mariana Trench in the western North Pacific is home to the Challenger Deep, which is the deepest point in the Pacific Ocean. 

Indian Ocean

There are three land masses surrounding the Indian Ocean, which are Africa, Asia, and Australia, which enclose it on three sides. There is a monsoon type of climate that prevails in the Indian Ocean region. During the summer season, cyclones are a common occurrence. It is also worth noting that this ocean is the warmest in the world as well. As a result of the warm tropical waters of the ocean, there exists a rich ecosystem in the area. An abundant phytoplankton population and aquatic flora enable a complex food chain to grow. Most of the fish caught in the Indian Ocean are exported to markets around the world, including tuna and shrimp.

Atlantic Ocean

There are relatively few islands in the Atlantic Ocean, but it contains most of our planet’s shallow seas. It borders four continents: Africa, Europe, North America, and South America. Among the world’s oceans, it is the second shallowest. The Atlantic Ocean covers an area of 85,133,000 square kilometers. Approximately 20% of the world’s surface is covered by the Atlantic Ocean. Although it is the second largest ocean in the world, it is the second youngest. With a salinity between 33 and 37 parts per thousand, the Atlantic Ocean is also the saltiest ocean in the world.

Arctic Ocean

One of the smallest, most icy, and shallowest of all the oceans in the world, the Arctic Ocean is situated in the Northern Hemisphere’s Arctic north polar region, which is home to the most frigid climate on the planet. Temperatures in the Arctic Ocean are frigid year-round due to its location in a polar climate zone. Summers are marked by continuous daylight as opposed to winters that are engulfed in darkness. The Arctic Ocean is home to four whale species, including bowhead whales, gray whales, narwhals, and beluga whales. As the climate continues to warm, these whales and other species are quite threatened. Due to global warming, the ice cover of the ocean is shrinking, with an average decline of 3% per decade.

Southern Ocean

Antarctica is surrounded by the Southern Ocean. Geographically, it is the most southern and fourth-largest of the 5 oceans. A large part of its surface is under water. Most of that surface is between 4,000 and 5,000 meters beneath sea level, which is significantly deeper than the oceans’ floors in the other five oceans. Despite the lack of a land mass to the north, the Southern Ocean is treated as a unique oceanic division because of its varied water properties south of 60° S latitude. Antarctica and the Southern Ocean are home to the world’s largest penguin species, the emperor penguin.

The photo featured at the top of this post is © Anton Balazh/Shutterstock.com