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23 Ocean Facts Exploring Our Planet's Vast Blue Expanse

The ocean is no doubt one of the many wonders of the world. From marine life to the calming nature of the waves, marine environments fascinate people worldwide. Water covers the majority of the earth's surface - a stunning 71%. Furthermore, oceans hold about 96.5% of all of the earth's water. 

These numbers show us how vital the deep ocean is to our world. Interestingly, all oceans operate as one large water body, regardless of if it's the Pacific Ocean or the Atlantic Ocean. In this article, you'll discover a selection of ocean facts that'll leave you even more fascinated by the deep blue depths surrounding us.

From general ocean facts to interesting ones and those that call for its protection, read on for fun facts about the ocean and some more serious eye-opening ones too. 

For more reading, you might like our article on how much the Earth costs, waves quotes, and answer how many plastic bags are in the Ocean.

General Ocean Facts

Divers pictured diving Mexico's island archipelago Revillagigedo, a UNESCO world heritage site. Photo by Francisco Jesús Navarro Hernández on Unsplash

1. The ocean is vast

One of the most obvious ocean facts is that the ocean is vast. The world's oceans cover about 71% of the earth's surface, with an average depth of 3,688 meters (12,100 feet). 

Also, the earth's oceans hold about 321 million cubic miles (1.34 billion cubic kilometers) of water. This is an estimated 97% of water in the world, with another 2-3% contained in ice caps. With so much of the earth's surface taken up by oceans, oceans considerably impact weather, food supply, and temperature.

2. Ocean habitats are the largest on earth

Ocean habitat
Photo by Olga Tsai on Unsplash

Much of life on our planet is aquatic. The ocean holds about 94% of the earth's wildlife and forms a huge living space for marine animals. This is not a surprise as the ocean takes up much of the earth's surface. Research estimates that about one million species of animals make the ocean their habitat. 

Moreover, the ocean is home to millions of plants and animal species in our world. This ranges from the smallest invertebrates like jellyfish and shrimp to large animals like whales, sharks, and dolphins. You'll also find animals like seahorses, sea lions, and sea turtles

It's pertinent to add that the largest animal ever to live on earth, the blue whale, is an ocean mammal. On average, 2000 new marine species are discovered each year. This life below water not only relies on oceans for living but also for food. 

Interestingly, researchers estimate that 91% of species that oceans in our world house await description3. Factors like ocean depth, water pressure, and temperature determine the kinds of animal life in particular areas. Whereas some ocean-dwelling animals live in shallow waters, many more remain undiscovered in the ocean's depths. Interestingly, many land animals have also adapted to spending considerable time in the planet's oceans.

3. The pacific ocean is the world's largest ocean

Although the ocean is one continuous body of salt water, oceanographers divide the ocean into four major basins. We have the Pacific Ocean, the Atlantic Ocean, the Indian Ocean, and the Arctic ocean. 

The Pacific, Atlantic, and Indian oceans merge into icy waters around Antarctica. In the same vein, some oceanographers define this as the fifth ocean, popularly called the Southern ocean. 

Among all, the Pacific Ocean is the largest. It covers a little over 30% of the earth's surface. That is, one-third of the earth's surface. The name, Pacific ocean, comes from the Latin word Tepre Pacifium which means peaceful sea.

Furthermore, the Pacific Ocean contains around 25,000 islands and houses one of the world's seven natural wonders - The Great Barrier Reef - also the world's largest living structure. In addition, we can divide the islands within the Pacific Ocean into three main groups: Micronesia, Melanesia, and Polynesia. 

4. The Atlantic Ocean is the second-biggest ocean

The Atlantic ocean is about half the size of the Pacific ocean. It's the second biggest ocean and covers roughly 20% of the surface of the earth. That is one-fifth of the earth's surface. It also contains 29% of the earth's water. The Atlantic Ocean covers an area of approximately 41,105,000 square miles. It derives its name from the Greek god, Atlas. Scientists divide the Atlantic into two basins: the North Atlantic and the South Atlantic.

5. The biggest ocean waves are below the ocean surface

The biggest ocean waves exist inside the ocean and aren't visible on the shores. These waves are internal waves. They are similar to waves we see on beaches. They have crests and troughs; they undulate and even break. 

Internal waves take place between two fluids of different densities. These waves are so big that they can move up and down over 200 meters below the surface. They also travel 1000s miles across ocean basins.

6. The ocean is home to the biggest animal - the Blue Whale

Blue Whale
Blue Whale - iStock

The largest animal to ever live on the planet is the blue whale. Not only is it the largest animal to live on the earth today, but it's also the largest animal to have ever existed. 

Records show the largest blue whale grew to 108 feet long - as tall as an 11-story building. A blue whale can weigh as much as 400,000 pounds. This weight is the equivalent of approximately 33 elephants and reaches up to 98 feet in length.

More reading: 20 Wondrous Whale Facts.

7. Oceans hold nearly 20 million tons of gold

There is gold in the oceans estimated at a staggering 20 million tonnes. The National Ocean Service has on record that there is about one gram of gold for every 100 million metric tons of ocean water in the Atlantic and North Pacific Oceans. 

Scientists estimate that there is enough gold in water for every human to have eight pounds of it each. However, the extraction of gold from water is more expensive than mining. Most of these ocean gold deposits exist a mile or two underwater, which makes extraction difficult. 

8. The world's longest mountain range is underwater

The longest mountain range in our world lies in the oceans. It's the Mid-Ocean Ridge with a size close to 40,390 miles long. It dwarfs the longest mountain range above the waters, the Andes, which is about 4300 miles long. 

This system of mountains and valleys crisscrosses the globe, resembling a baseball. Its formation is a result of the earth's tectonic plates. 

9. The ocean produces 50-80% of the planet's oxygen

Oceans are more vital to our survival than we know. Contrary to the popular opinion that the majority of the oxygen we breathe comes from rainforests, oceans provide most of the earth's oxygen. 

Studies reveal that the ocean produces more than half of the earth's oxygen. Tiny marine plants in the ocean, specifically kelp, algal plankton, and phytoplankton, are our greatest source of oxygen. 

10. Ocean water is constantly moving

Ocean water is constantly moving
Photo by Paul Buffington on Unsplash

Ocean sea water is constantly in motion. The motions result from waves, wind, tides, currents, the Coriolis effect, water density differences, and the shape of the ocean basins. 

Some ocean currents flow at the surface level, while others flow deep within the water. Also, water moves around the globe in sweeping currents. Waves and tides rising and falling transfer energy across ocean basins daily.

The Gulf Stream, a current of warm water in the Atlantic Ocean, moves an amount of water larger than all of the world's rivers on land combined, according to NOAA

11. Oceans have lakes and rivers

Just like you'll find a lake or river on the surface of the earth, oceans too have these water bodies. Their formation results from salt water and hydrogen sulfide combination that becomes denser than the rest of the water around it. This enables it to form a lake or river that flows beneath the ocean. 

Additionally, these underwater lakes and rivers drastically range in size from only a few feet to a few miles wide. 

Interesting Ocean Facts

12. There are millions of shipwrecks lying on the ocean floor

Diver exploring a shipwreck off the coast of the Maldives. Credit: iStock

Estimates reveal that more than 3 million shipwrecks dot the ocean floor. Less than 1% of these wrecks have been explored. 

The oldest shipwreck, the Dokos shipwreck, dates back years to 2700 - 2200 BC, while the RMS Titanic sank on 15 April 1912. Also, there's the torpedo of Russian marines during the Second World War. These occurrences claimed many lives and are a mere few examples of shipwrecks in the ocean.

13. Undersea cables power the global internet 

Global communication is made possible by undersea cables. The internet relies on cables crossing the ocean floor between continents and land masses. 

This network has a length of over half a million miles. It consists of over 200 independent systems of connected cables and carries over 95% of global communication. Today more than 99% of international communications are carried over fiber optic cables, most of which are undersea. 

14. Most volcanic eruptions occur underwater 

The ocean takes the lead when it comes to the earth's volcanic activity. Eighty percent of the earth's volcanic activities happen in the ocean, and The South Pacific is famous for having the largest concentration of active volcanoes.

There is an estimated 1 million volcanoes underwater. In addition, these underwater eruptions occur regularly, forming new land masses and providing a living environment for deep-sea creatures. Scientists discovered the West Mata, the deepest ocean eruption ever found, in 2009. 

15. The ocean is blue because of how it absorbs sunlight

There's the misconception that the ocean is blue because it reflects the sky's color. However, the ocean is blue because of how it absorbs light in the red part of the light spectrum. 

When sunlight hits the ocean, the water absorbs the long-wavelength colors at the red end of the light spectrum and the short-wavelength light.

The remaining visible light is mainly made up of blue wavelength. The water acts as a filter, leaving behind colors in the blue part of the spectrum. Furthermore, the ocean can take on other colors like red and green. This happens if sunlight bounces off floating sediments or particles in the water.

16. The ocean contains more ancient artifacts than any museum 

One of the mind-blowing fun facts about oceans is that they hold artifacts. The ocean houses countless numbers of treasures and artifacts. Artifacts from Titanic have an estimated value of 189 million dollars. 

Research shows that there are more historic artifacts under the sea than in all of the world's museums combined. Interestingly, these artifacts aren't from shipwrecks alone. Airplanes from wars and civil aviation also end up in the waters. We can refer to the ocean as the planet's mega museum. 

17. Humans haven't explored more than 80% of the ocean

Here is another one of the fun facts about oceans. Research shows that over 80% of the ocean hasn't been explored. There are still many mysteries about the ocean, as a mere 5% of the ocean has been explored and charted. 

In fact, there are better maps of Mars than the ocean, even with its great distance of nearly 50 miles away from the Earth. As researchers strive to discover more, new things about what lies beneath the ocean come to light.

Read more: How Much of the Ocean Has Been Explored? — History and More.

18. Light doesn't penetrate the bottom of the ocean

The ocean has an average depth of 12,100 feet. Because light waves can only penetrate 330 feet of water, the remaining part of water does not have light penetration. This makes the bottom of the ocean dark. 

Light in the ocean decreases with depth. The reason for this is that the ocean is very deep. Light can only penetrate so far below the ocean's surface, leaving the bottom without light. 

Without light, saltier cold water is found at the bottom of the deep ocean creating an environment full of weird and wonderful creatures adapted to live in these conditions.

19. Corals have natural sun protection 

Corals have natural sun protection
Photo by Milos Prelevic on Unsplash

Coral produces its own sunscreen. Too much exposure to sunlight can damage the algae that inhabit coral in shallow water. As a result, coral produces natural sun protection. It creates proteins that act as a kind of sunscreen to protect algae. This is called a fluorescent pigment. Algae are the primary source of sustenance for coral, hence the need for protection.

Read more: Coral Facts.  

20. About 75% of deep-sea creatures create their own light 

A large variety of animals like fish, worms, jellyfish, octopuses, squid, and crustaceans can emit their own light. This phenomenon is called bioluminescence. Bioluminescence is an ecological trait expected of all animals living in water because of its immense importance. These sea creatures use this light to hunt, ward off predators, or attract mates.

Related read: Brilliant Bioluminescent Beaches.

Environmental Ocean Facts

21. The sea level is rising by 3.4 millimeters per year

As a result of warmer ocean temperatures as well as melting glaciers and ice sheets, global sea levels are rising. Between 1900 and 1990, studies showed that the sea level increased by 1.2 millimeters and 1.7 millimeters on average. The rate increased in the year 2000 to 3.2 millimeters. In 2016, it had an estimated value of 3.4 millimeters per annum5. Also, China's coastal sea levels increased by 3.4 millimeters per annum between 1980 and 2020. 

22. The ocean is becoming more acidic

The average PH of the ocean is 8.2, which is basic or alkaline. However, the PH decreases as the ocean absorbs carbon dioxide released into the atmosphere by humans. Therefore, it becomes acidic. 

The PH level of the ocean has dropped on average from 8.2 to 8.1 PH, or a 26% drop in the PH level1

Since the industrial revolution, the concentration of carbon dioxide in the atmosphere has increased. This is due to human activities like burning fossil fuels and changing land use. Also, the ocean absorbs about 30% of the carbon dioxide released into the atmosphere. As a result, it becomes more acidic.  

23. The top part of the ocean is warming up around 24% faster than it did some decades ago

Ocean meeting land
Photo by NASA on Unsplash

Since the commencement of the Industrial Revolution in not-so-distant history, humans have engaged in activities that have pumped heat-trapping carbon dioxide into the atmosphere. In response, the planet has warmed up. 

Only about 1% of this carbon dioxide stays in the atmosphere, and the remaining goes into the vast ocean. Recently, the warm water rate has been accelerating. The top part of the ocean is warming up at about 24% faster than it did some decades ago. This warming up harms marine life, storm intensity, and more. Without caution, there's still a tendency for this trend to accelerate. 

24. Millions of tons of plastic enter the ocean every year

Ocean plastic by the shore
Plastic on the shore. Photo by Lucien Wanda

Plastic pollution is a pressing environmental issue. This happens due to the rapid increase in the production of disposable plastics and fewer management abilities. 

The plastic pollution facts are staggering, with about 14 million tons of plastic entering the ocean annually2. Additionally, an estimated 5.25 trillion pieces of plastic exist in the ocean. Microplastics can make their way into the human body when we eat marine organisms. 

25. A plastic bag is the deepest known piece of plastic trash

A plastic bag is the deepest recognized piece of plastic trash because it resides in the Mariana Trench. The Mariana Trench is the deepest point in the ocean. It spans 10,975 meters (36,000 feet) down the remote part of the Pacific Ocean. The lowest known point is called challenger deep. 

Additionally, it has a crescent shape and reaches more than 7 miles below the surface of the Pacific Ocean4. It's also an abode to distant alien marine forms which humans don't know about. Even with the depth of this trench, the plastic bag has made its way down there.

Related: How many plastic bags are in the ocean?

26. Coral reefs are declining

The world's coral cover on tropical reefs has substantially declined over the last 40 years. Some causes of the decline of coral reefs include climate change, overfishing, pollution, declining water quality, and unsustainable coastal development. Consequently, this decline poses a threat to the habitats of indigenous islands since they feed on coral.


Oceans are home to many wonders, and many people love being by seawater. The sea simply being an ocean area with land covering several sides. Oceans house different species of sea creatures. We also know considerable undiscovered treasures lie on the seafloor. 

Despite how much we know and enjoy the ocean, humans have explored only 5% of it. What other discoveries might we unearth as we explore a more significant percentage? 

It's certainly interesting to uncover what lies beneath the water's surface. Whether you're an aspiring marine biologist or just a curious mind, you'll appreciate these ocean facts, all of which point to the need to protect the world's oceans.


Cornwall, Christopher & Comeau, et al., (2021). Global declines in coral reef calcium carbonate production under ocean acidification and warming. Proceedings of the National Academy of Sciences. 118. e2015265118. 10.1073/pnas.2015265118.


Justine Barrett et al., Microplastic Pollution in Deep-Sea Sediments From the Great Australian Bight, Front. Mar. Sci., 05 October 2020, Sec. Marine Conservation and Sustainability https://doi.org/10.3389/fmars.2020.576170


Public Library of Science Biology. (2011, July 13). How Many Species Are There on Earth and in the Ocean?


Live Science. (2022, May 10). Mariana Trench: The Deepest Depth.


Smithsonian Institute. (2018, April). Sea Level Rise. 

By Jennifer Okafor, BSc.

Jen’s a passionate environmentalist and sustainability expert. With a science degree from Babcock University Jen loves applying her research skills to craft editorial that connects with our global changemaker and readership audiences centered around topics including zero waste, sustainability, climate change, and biodiversity.

Elsewhere Jen’s interests include the role that future technology and data have in helping us solve some of the planet’s biggest challenges.

Photo by Jeremy Bishop on Unsplash
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