Mariana Trench

The Mariana Trench is the deepest part of the ocean on Earth. It is found in the western Pacific Ocean, about 200 kilometres east of the Mariana Islands. This huge trench is shaped like a crescent wrench and stretches for about 2,550 kilometres. Its deepest point, called the Challenger Deep, is more than 11,000 metres below the surface—deeper than Mount Everest is tall!

At such amazing depths, the water puts out a lot of pressure—about 1,000 times more than what we feel on land! Even though it is very cold at the bottom, scientists have found tiny living things living there. These include special single-celled creatures called monothalamea and tiny microbial life forms that manage to survive in this extreme world.

In 2009, the United States protected part of the trench by creating the Mariana Trench Marine National Monument. This helps keep this amazing place safe for future exploration and study.

Etymology

The Mariana Trench is named after the nearby Mariana Islands. These islands are called Las Marianas to honor Spanish Queen Mariana of Austria. The islands sit on a moving plate called the Mariana plate, located on the western side of the trench.

Geology

The Mariana Trench is part of the Izu–Bonin–Mariana subduction system. This is where two large pieces of Earth's surface, called tectonic plates, meet. One plate, the Pacific plate, moves under another smaller plate, the Mariana plate. This movement makes deep valleys in the ocean floor.

The movement of these plates also helps create the Mariana Islands. These islands form when melted rock from deep inside the Earth rises to the surface.

Research history

See also: Challenger Deep

The Mariana Trench was first explored in 1875. They used a weighted rope and found it very deep. Later, better tools helped measure the depth more accurately.

In 1951, a team led by Thomas Gaskell used echo sounding to find the deepest part, called the Challenger Deep. Other scientists kept studying the trench with advanced tools. In 1995, a remote vehicle named KAIKO reached the bottom.

Between 1997 and 2001, scientists found another deep spot and named it the HMRG Deep. In 2009, mapping tools helped make detailed maps of the trench.

In 2012, researchers used special equipment to study the area under the trench.

As of 2022, 22 people and seven uncrewed vehicles have reached the bottom of the Mariana Trench. The first successful dive was in 1960 by Don Walsh and Jacques Piccard in the bathyscaphe Trieste. Since then, others have made dives, including James Cameron in 2012 and Victor Vescovo in 2019.

In 2015, scientists placed a listening device in the trench. In 2019, an underwater vehicle named Vityaz-D made a dive to the bottom. In 2020, a Chinese submersible named Fendouzhe also reached the deepest part.

Life

Scientists found many amazing creatures living deep in the Mariana Trench, even though the pressure there is very high. In 1960, they thought they saw a small flatfish and some shrimp on the trench floor. Later, tiny organisms were found in mud from the seabed. In 2011, researchers used special cameras and found huge single-celled organisms, some bigger than a pencil.

In 2014, a new type of snailfish was found living very deep, setting a record for the deepest fish ever seen on video. Scientists also filmed large amphipods, which grow bigger than their relatives in shallower water. This is called deep-sea gigantism.

Pollution

In 2016, scientists studied small sea animals from the trench and found harmful chemicals in their bodies. They also found tiny pieces of plastic inside them. In 2019, a plastic bag and candy wrappers were found at the very bottom of the trench. Scientists also found traces of carbon-14, a substance from old nuclear tests, in sea animals from the trench.

Possible nuclear waste disposal site

The Mariana Trench has been suggested as a place to store nuclear waste. Some people believe that the movement of Earth's plates might push the waste deep into the Earth. However, putting nuclear waste in the ocean is not allowed by international law. These areas can also have very large earthquakes, which makes it unsafe for storing nuclear waste.