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What lives at the bottom of the Mariana Trench?

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Imagine a mountain taller than Mount Everest. Or a canyon five times bigger than the Grand Canyon. Now, imagine it's in an untouched place in the deepest part of the ocean. That is the Mariana Trench. Could anything live in such a place? If so, which Mariana Trench animals might you spot?

Discover the life at the bottom of the Mariana Trench, including how it was formed and exciting facts most people don't know about this mysterious place.

What is the Mariana Trench?

What lives at the bottom of the Mariana Trench 1
The Mariana Trench is the deepest trench on Earth with a maximum depth of 36,037 feet.

© iStock.com/ratpack223

Trenches are long, deep depressions on the ocean floor that usually run parallel to plate boundaries. The Mariana Trench, or Mariana Trench, is located in the western Pacific Ocean about 124 miles east of the Mariana Islands. The Mariana Trench is the deepest ocean trench on Earth.

The scarred trough has a maximum depth of 36,037 feet, nearly seven miles. The deepest ocean known to man is at the southern end of the trench, the Challenger Deep, at a depth of 36,201 feet (not double measured). So far, only 12 people have dived into the Mariana Trench, out of a total of 22.

Although the water at this depth is cold, about 34° to 39° Fahrenheit, it's the enormous pressure that makes this area so dangerous. The pressure is 1000 times higher than standard sea level atmospheric pressure.

How did this mysterious, dark trench form, and what inexplicable creatures live in it?

How was the Mariana Trench formed?

Underwater volcanic activity in Flores, Indonesia
The subduction process lasted 50 million years and formed the Mariana Trench.

©Ethan Daniels/Shutterstock.com

At 180 million years old, the seabed of the Western Pacific Ocean is one of the oldest in the world. This ancient crust contains thin plates floating on lava (the mantle). Sometimes these plates collide with each other, causing one plate to plunge into the mantle while the other straddles the top.

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This process is called subduction, and this movement can lead to the formation of ocean trenches, volcanoes, earthquakes and tsunamis. The Mariana and Pacific plates are responsible for creating the Mariana Trench, which lies on this subduction zone.

Although the process sounds simple, the subduction of the Mariana plate has occurred for more than 50 million years. The trench is arc-shaped, and researchers speculate that it was formed when the Mariana plate broke away from the Philippine plate. The formation of the Mariana microplate (which inevitably collided with the Pacific plate) is responsible for the formation of the Mariana Islands, an archipelago of active and dormant volcanoes. While the system continues to grow, the scientists believe the Mariana microplates will eventually dissipate.

What lives at the bottom of the Mariana Trench?

mariana trench
Deep-sea amoebas, shrimp-like creatures and sea cucumbers live on the bottom of the Mariana Trench.


Mariana Trench animals include xenozoans, amphipods and small sea cucumbers (sea cucumbers), all of which live on the floor of the ocean's deepest depression. Animals living at these depths survive in total darkness and extreme pressure, consuming chemicals such as methane or sulfur or those downstream in the food chain.

Scientists studied the creatures found in video footage from James Cameron's 2012 expedition. Unfortunately, due to the extreme dangers of exploring the deep ocean, not much evidence is available. With more than 80% of the ocean unexplored, the potential for new species to emerge is enormous.

Exotic plants

Xenophyophores ("foreign body carriers") are giant deep-sea amoebas among the world's largest single-celled organisms. Living in the deepest parts of the ocean, these protozoans are poorly understood because their fragile skeletons make them difficult to collect for study.

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These creatures come in various shapes and sizes, resembling spherical sponges, frilly sponges, tetrahedrons (tetrahedrons) or flat discs. Xenophyophores are essentially cytoplasmic masses, a viscous fluid containing the nucleus.

They secrete a glue-like excrement that attaches to minerals and other objects in the environment, such as skeletal remains, and uses it to form an exoskeleton known as a test. Xenophyophores move along the ocean floor like slugs and have no known predators.


Amphipods are soft crustaceans without a shell, usually flattened on the sides.

© Urban Tropical/Shutterstock.com

Amphipods are small crustaceans found throughout the oceans, but one species in particular inhabits this deep-sea trench. Hirondellea Gigas is a shrimp-like creature about two inches long that feeds on fallen logs on the seafloor. These creatures can go without food for long periods of time, but will eat almost anything, and will gorge themselves to the point of bursting.

These amphipods produce xylophilous enzymes in their guts that scientists believe are used to make ethanol. Ethanol helps make drugs, plastics and cosmetics.

sea cucumber

Sea Cucumber is a new glowing sea cucumber. Although these soft creatures look like plants, they are actually animals closely related to starfish and sea urchins. Sea cucumbers are strange creatures with unusual defense mechanisms. When threatened, sea cucumbers contract their muscles and squeeze their internal organs out of the anus.

Cucumbers observed in deep grooves of the earth are bright violet, transparent. The most famous deep-sea cucumber is called "headless chicken monster". It might sound scary, but watching this unusual species move through the water looks like a strangely graceful aquatic ballet.

Mariana snail

The Mariana Deep snailfish is the deepest fish ever found from the Mariana Trench. Researchers caught the record-breaking fish at 27,460 feet below sea level, and scientists speculate the fish reached a maximum depth of 27,900 feet. This snailfish has adapted to a life of extreme stress and total darkness. It has transparent skin, no eyesight, and is one of the top predators in the Mariana Trench.

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Fun Facts About the Mariana Trench

  • In 1960, Don Walsh (U.S. Army lieutenant) and Jacques Picard (engineer) were the first to dive deep into the Mariana Trench.
  • The United States controls the deepest part of the trench, the Challenger Deep, and holds it as a national monument.
  • If Mount Everest (the tallest mountain in the world) were placed inside the Mariana Trench, its peak would still be 7,000 feet below sea level.
  • The Mariana Trench is the deepest place on Earth and is extremely polluted. The levels exceed those found in heavily polluted Chinese rivers.
  • Divers in the trench recovered plastic bags and candy wrappers. Humans still affect the most remote places in the world.
  • Researchers have recorded strange metallic sounds coming from the Mariana Trench. After much debate, they concluded that the sound came from baleen whales.
  • What lives at the bottom of the Mariana Trench? New unique creatures, and many more that scientists haven't discovered yet!


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featured image

mariana trench
Primitive organisms in dark deep water, jelly, single cell

© Fona/Shutterstock.com

about the author

Niccoy is a professional writer and content creator focusing on nature, wildlife, food and travel. She graduated from Florida State University with a business degree before realizing that writing was her true passion. She lives in the foothills of the Rocky Mountains and loves hiking, reading and cooking!

FAQ (Frequently Asked Questions)

Where is the deepest part of the Mariana Trench?

The deepest part of the Mariana Trench is Challenger Deep. There is some debate about its exact depth versus the commonly used measurement of 35,827 feet. However, the Soviets reported a maximum depth of 36,201 feet on a dive in 1957.

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