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8 Amazing Facts About the Ocean
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Chances are good that you’ve been swimming in the ocean or gone on a school trip to the aquarium. You might have also learned some basic information about the ocean. For instance, most people know that Earth’s oceans make up a huge portion of the planet’s surface and that they are home to huge numbers of unique aquatic life forms. But what do you really know about the ocean? We created a list of facts about the ocean to make it easy to learn something new about the big blue sea! So, if you want to learn a few new facts about the ocean, read on.

#1 Oceans Cover Over 70% of Earth’s Surface.

Oceans cover over 70% of the Earth’s surface. This figure only serves to underscore how vital our oceans are to the planet. Yet, large parts of Earth’s oceans remain a mystery to humans. In fact, according to the National Ocean Service, over 80% of Earth’s oceans remain unmapped, unobserved, and unexplored!

#2 94% of Life on Earth Is Aquatic.

With so many species living on land, you might think that most life on Earth exists on land. But an incredible 94% of life on Earth lives in our oceans. When you consider that 70% of Earth’s surface is covered by oceans, this number makes a little more sense. To date, we still don’t have a good idea of exactly how many species live in the ocean, but scientists estimate that as many as 91% of ocean species have yet to be classified.

#3 Oceans Play an Important Role in Climate Control.

By moving water around the Earth, oceans help to keep various areas from getting too hot or too cold. Oceans also help keep the planet warm by storing heat. Ocean currents then carry that heat around the planet. If you're wondering how the concept of the ocean storing heat works, think about the way that water stays warmer for longer when it is stored in a large basin, like a bathtub, than it does in a small mug. Then think about the sheer size of the ocean and how much heat it is capable of holding!

#4 More Than 70% of Earth’s Oxygen Is Produced by the Ocean.

The ocean truly is essential to life on Earth. Over 70% of the planet’s oxygen is produced by marine plants living in the ocean – most of these are species of marine algae. Without the Earth’s oceans, we wouldn’t have enough oxygen to breathe!

#5 The Ocean Looks Blue Because of the Sun.

The ocean appears blue because the surface of the water absorbs red and orange wavelengths of light from the Sun, but the blue wavelengths penetrate deeper, giving the ocean its characteristic hue. The ocean appears bluer the deeper you go because the blue wavelengths can travel further down. So why doesn’t the water in a small glass or jug look blue, too? It’s because there aren’t enough molecules to absorb the wavelengths and create this effect.

#6 The Mariana Trench Is the Deepest Point on Earth.

The Mariana Trench is considered the deepest part of the ocean as well as the deepest point on Earth. Inside the Mariana Trench, there is a valley called Challenger Deep. It extends approximately 7 miles (36,070 feet) below the surface – for comparison, Mount Everest is 29,029 feet high and could easily fit inside the valley. While crewed explorations have been limited, humans successfully reached a depth of 35,797 feet below the surface in 1960. Filmmaker James Cameron reached roughly the same depth on a solo mission. Recently, Victor Vescovo became the first person to reach the deepest part of the ocean in 2019.

#7 There Are Rivers and Lakes in the Ocean.

Rivers and lakes can exist in the ocean. How? Water from under the sea floor sometimes seeps up through a thick layer of salt that is present beneath the sea floor. As the water seeps up, it dissolves the salt layer, causing it to collapse and form depressions. Because of the dissolved salt, the water in these depressions is denser than the water around it, so it settles into the depression and forms a river or lake. These rivers and lakes can be very small or up to a few miles long. They behave like lakes and rivers on land – they even have shorelines, surfaces, and waves!

#8 The Ocean Has Underwater Waterfalls.

In fact, the Earth’s largest waterfall is in the ocean! It is located beneath the Denmark Strait, which separates Iceland and Greenland. But how are underwater waterfalls even possible? Underwater waterfalls are possible because cold water is denser than warm water. When the denser cold water sinks below the warm water, under the right conditions, a waterfall can form. The waterfall beneath the Denmark Strait is a good example. At the bottom of the strait there are a series of cataracts that begin at 2,000 feet at one end and plunge to a depth of 10,000 feet on the other, creating a huge drop. When the southward-flowing cold water from the Nordic Seas meets the warmer water from the Irminger Sea, the colder, denser water sinks below the warmer water and flows along the massive drop, creating an underwater waterfall! As the Earth’s largest waterfall, the rate of flow is incredibly powerful – scientists estimate that the water flows downward at more than 123 million cubic feet per second.

Want to learn more amazing facts about oceans? Watch this video!

Still craving some more science facts? Why not check out our article on sharks or read through our roundup of facts about water?

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