American Oceans
An illustration of a boat over the Mariana trench

How Deep Is the Ocean?

Located in the western Pacific Ocean, in between Guam and the Philippines, the Mariana trench is known as the deepest part of the ocean.

What is the Deepest Part of the Ocean?

The ocean is a world of its own. What we can visibly see of the ocean is only a fraction of what is out there. The oceans of planet Earth are massive; they contain exotic, otherworldly environments and help sustain life on our planet. 

A scuba diver in deepwater with flashlight

Although explorers and adventurers have gradually chipped away at the ocean’s treasure trove of secrets, many secrets remain untouched. 

We may have learned a great deal about the ocean over the centuries, but there is still much to learn and many questions unanswered. With such a vast expanse of water across the planet, you might find yourself wondering, what is the deepest part of the ocean? 

The deepest part of the ocean is an oceanic trench that is larger than the Grand Canyon! It’s a place of wonder, mystery, and unfathomable depths; it’s called the Mariana Trench.

Introduction to the Mariana Trench

Map showing location of Mariana trench

Far below the sea, there is a 1,580 square mile space called the Mariana Trench. This crescent-shaped depression in the Earth’s crust is nearly 36,070 feet deep! The incredible depth of the Mariana Trench makes it the deepest known part of the ocean by far. 

The exact depth of the Mariana Trench remains unknown. So far, it is over 36,000 feet deep as far as scientists have been able to track. Of course, it could be even deeper; researchers and explorers haven’t yet traversed the entire trench. But it remains the single deepest place known to man in any ocean on Earth. 

To illustrate exactly how significant the depth of the Mariana Trench is, consider this. The Mariana Trench is deeper than any mountain on Earth is tall. The sheer depth of the Mariana Trench dwarfs even the legendary height of Mount Everest. Imagine standing at the base of Mount Everest, with water reaching above the highest peak!

If you were to actually look upward from the Mariana Trench’s bottom, you would see the tallest rock formation in the world. 

Of course, this would be impossible because the pressure at the bottom of the Mariana Trench would be so incredibly great, your body would not be able to withstand it, even in a diving suit. It’s also very dark.

Still, some explorers have dived to the depths in unique ways.

1960 Challenger Deep Expedition

Jacque Piccard and Lieutenant Don Walsh of the United States Navy reached the bottom of Challenger Deep in 1960. Challenger Deep is thought to be the deepest part of the Mariana Trench.

While Walsh and Picquard’s successful expedition was inspiring, there is still much to discover about the ocean’s deepest part. But the incredible amount of pressure in the Mariana Trench makes it incredibly challenging to explore its mysterious depths.

It may take many years of technological innovation to complete the Mariana Trench exploration, if ever. 

2021 Space-Deep Dive

In early 2021, Richard Garriott hopped aboard a deep submergence vehicle to head down into Challenger Deep. Garriott has also traveled from pole to pole and into space, but diving down into the Mariana Trench was something new for the explorer.

The expedition aimed to collect some rock samples, but that didn’t work out the way the team had hoped. But they collected plenty of data — and photographs — to bring back. In fact, they also took measurements of their submarine vehicle and found that it shrunk due to the pressure of the water at those depths. 

Descending into the trench took about four hours, which is certainly shorter than most outer space adventures. Still, there’s much to learn about the depths of the ocean, and more expeditions like Garriott’s are no doubt in the future. 

Interesting Facts About the Deepest Part of the Ocean

Deep ocean view of sunlight hitting ocean underwater

Even though there is still a lot that we don’t know about it, there are still plenty of interesting facts that we do. At 180 million years old, the Mariana Trench is not just the deepest part of the ocean; it also happens to be one of the most ancient seabeds on Earth. 

How did the Mariana Trench get its name? Discovered in 1875, the Mariana Trench was named after the nearby Mariana Islands.

The HMS Challenger, using its sounding equipment, discovered the Mariana Trench. The late 1800s were an age of discovery in which people enjoyed a combination of maritime technology and a thirst for discovery. 

Mariana’s Tectonic Plates

One fact that researchers learned is that the shape and geographical features of the Mariana Trench is due to interactions between the Earth’s tectonic plates. 

Two tectonic plates moved in such a way that they birthed the volcanic Mariana Islands and influenced the creation of the Mariana Trench. Seismic surveys of the Mariana Trench are still ongoing, and the activity in the trench is “dragging” water into deep Earth, researchers say. 

More water than scientists realized that the subduction zones are sucking water miles below the surface of the Earth. Such research reveals that Earth’s water cycle is far more complicated than scientists thought!

Life in the Deepest Part of the Ocean

Contrary to what you might expect from the deepest part of the ocean, the Mariana Trench supports many life forms. The Mariana Snailfish is perhaps one of the most iconic residents of the Trench. 

The Mariana Snailfish’s body structure even inspired the creation of the soft robot that made a recent dive 10,900 feet under the Mariana Trench’s surface.

As the deepest part of the ocean, the Mariana Trench is not a particularly inviting place. It’s a highly acidic environment that is virtually devoid of sunlight. Yet the black depths of the Mariana Trench support 200 microorganisms, including amphipods and a surprising variety of crustaceans. 

One of the most exciting prospects of the continued efforts to explore the Mariana Trench is the possibility of discovering new species. After all, as surprised as researchers were to learn that many species thrive so deep under the ocean, now they realize there are even greater possibilities lurking under the surface.

Although it is true that the more we uncover, the less there is to know, there is something glorious about the idea of discovering new species living in the deepest part of the ocean. 

What Else Lies in the Mariana Trench?

Trash at the bottom of the ocean

Appreciation for the Earth’s natural treasures often comes with a dedication to environmentalism. Litter and pollution is a well-known issue, and it has even reached the Mariana Trench. Improperly discarded waste has been located in the trench itself.

The fact that waste, including metal and plastic, has been found in the Mariana Trench should be an obvious cause for concern. That garbage has traveled so far and made its way to the deepest part of the ocean reminds us of our actions’ impact. 

The Mariana Trench is the deepest, most remote part of the ocean, meaning if waste can be found there, it can be anywhere. 

Take a minute to think about what kind of world you want. Would you rather live in a world brimming with life? Or one where future explorers are discovering plastic in the depths of nature?

Final Thoughts

We hope to have aroused in you a passion for scientific, biological, geographical, and geological discovery. We share a truly unique planet, one that is full of life, mystery, and wonder. 

Now that you know where the deepest part of the ocean is, we encourage you to continue your own journey of discovery and make an effort to learn even more. Who knows what you might uncover?

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