The Mariana Trench, located in the Western Pacific, 300 km east of the Mariana Islands, is the deepest ocean trench on the planet, reaching an impressive 11,034 meters in depth!
This means that no other place on earth is so deep and so close to the Earth’s core.
By way of comparison, Mount Everest, the highest mountain on the planet, is 8,848 meters high.
If Everest were transported to the bottom of the Mariana Trench, there would still be 2.2 kilometers (1.36 miles) left from the top of the mountain to the surface. Incredible, isn’t it?
It is also gigantic in terms of extension. It is 2,250 kilometers (1,398 miles) long and 69 kilometers (42 miles) wide.
Since it was discovered in the second half of the 19th century, the Mariana Trench has been studied by scientists, intrigued by the mysteries of this inhospitable zone.
Access to this abyssal depth can only be accomplished with the aid of advanced technology, since the pressure down there is up to a thousand times greater than on the surface.
Venturing into such conditions would cause the human body to be completely crushed.
We still know very little about the ocean floor. In terms of topography, we know more about the lunar surface than about the bottom of the oceans.
Thus, it is correct to say that the Mariana Trench is the least explored area on the entire planet.
Challenger Deep: the lowest point on earth
The Mariana Trench is not uniform or flat. This means that there are slopes, as well as deeper points than others.
The deepest location of the Mariana Trench – and therefore of the entire surface of the planet – is at the southern end of the oceanic trench, 11 kilometers (6.83 miles) deep.
This name is due to the name of the ship used by the researchers who, in 1874, discovered the Mariana Trench.
For 4 years, the English ship Challenger covered more than 110 thousand kilometers with the mission of carrying out the first mapping of the ocean floor.
Every 225 kilometers, the researchers threw a rope, with lead at the end, to measure the depth of the site.
Until one day, about 300 kilometers from Guam Island, in the southern tip of the Mariana Islands, the big surprise came: the rope kept going further down!
When it finally hit the ground, reaching the bottom of that huge hole, unimaginable 8 kilometers (4.97 miles) were measured!
They discovered the trench, not the Challenger Deep. The latter was only properly located with the aid of a sonar (a device that emits sound waves, which reflect on solid obstacles) in an expedition carried out in 1951.
Have we reached the bottom of the Mariana trench yet?
Yes, we have visited the Mariana Trench 3 times.
The first expedition took place in 1960, and those responsible for this pioneering dive, considered to be the most dangerous dive in history to date, were the United States Navy Lieutenant Don Walsh and Swiss engineer Jacques Piccard.
Onboard of the bathyscaphe Trieste, which was 15 meters long and had a buoyancy control system that used lead weights, Walsh and Piccard spent 9 hours inside a compartment slightly larger than a refrigerator.
At 10.9 kilometers (6.77 mi) deep, they saw sea life through the small windows.
The second expedition became a documentary
The second descent to the Mariana Trench occurred in 2012. And the film director James Cameron, author of Titanic, performed the feat.
Few people know, but Cameron is also an explorer. Thus, combining scientific and cinematographic interest, he embarked on this dangerous mission of exploring the deepest place in the ocean.
There were a total of 7 years of preparation. Until on March 25, 2012, Cameron became the first person to descend alone to the deepest point of the Mariana Trench.
Onboard the Deepsea Challenger submersible, he reached 10,898 meters deep.
The purpose of the expedition, coordinated by National Geographic, was to take samples of rocks and animals, and also to capture images using cameras capable of withstanding enormous pressures.
Everything is recorded in the documentary Deepsea Challenge 3D, released in 2014.
The third expedition: the greatest depth reached by humans in the sea
In May 2019, American explorer Victor Vescovo broke a record: he reached 10,927 meters below the surface aboard the ultra-resistant DSV Limiting Factor submersible.
Never has a human being managed to go so far.
There were five dives, during which Vescovo collected samples of stones and discovered new species of crustaceans and marine worms.
An unfortunate “discovery” of that expedition was a plastic bag filled with candy wrappers. Unfortunately, not even the deepest place on the planet escapes pollution.
How the Mariana Trench was formed
Oceanic or abyssal trenches are the deepest places in the oceans and resemble valleys or canyons of gigantic proportions.
They are formed by the collision between tectonic plates, which causes the heavier plate to slide under the lighter one. Those regions where the trenches are formed are known as subduction zones.
Therefore, what formed the deepest subduction zone in the world, better known as the Mariana Trench, is the convergence of two tectonic plates, the Pacific Plate and the Philippines Plate.
About 50 million years ago, the Pacific Plate slid under the Philippines Plate, “diving” into the Earth’s mantle (which is the layer of the Earth’s structure just below the crust).
The tectonic plates still move. This means that the Earth’s crust still moves on the Pacific Plate towards the subduction zone of the Mariana Trench.
Some curious animals that live in the Mariana Trench
Between April and July 2016, American researchers linked to the National Oceanic and Atmospheric Administration (NOAA), a US government agency, carried out a mission to collect information about the biology and geology of the Mariana Trench.
Here are some animals photographed by the Deep Discoverer, a remotely operated vehicle.
This species of enteropneusta (class of invertebrate animals) usually lives buried in the mud of the bottom of the oceans.
This other type of enteropneusta, also known as “acorn worm”, was spotted at the bottom of Sirena Canyon, in the Mariana Trench.
3. Megalodicopia sp
This predatory tunicate lives in great depths. Its open “mouth” is an efficient trap for plankton and small animals.
From the family of Aphyonidae, this type of fish, which looks like an eel, can reach 10 centimeters as an adult and has no scales. It is the first time that such a fish has been spotted alive.
This unidentified jellyfish lives in the darkness of the Mariana Trench. What a beautiful and strange discovery!
This octopus was seen during a dive near the Ahyi submarine volcano, in the Northern Mariana Islands.
This fish, of an unidentified species, lives in complete darkness, thousands of meters deep. Therefore, it lives in a hadal zone – a term that, in marine biology, designates the ecosystem of very deep zones.
8. Slit-shell snail
This new species of snail was discovered during NOAA researchers’ dives in 2016.