The Mariana Trench is the world's largest marine trench, and it contains the planet's two lowest points.
The crescent-shaped trench is found in the Western Pacific, near Guam, just east of the Mariana Islands.
The region surrounding the trench is notable for a variety of peculiar ecosystems, including vents that emit liquid sulfur and carbon dioxide, active mud volcanoes, and marine life that has evolved to pressures 1,000 times greater than at sea level.
A recent investigation indicated that a plastic bag, similar to those given out at grocery shops, has been discovered at a depth of 10,975 meters (36,000 feet) beneath the Mariana Trench.
Scientists discovered it while searching the Deep-Sea Debris Database, a recently made public collection of photographs and videos from 5,010 dives over the last 30 years.
How does Mariana trench form?
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The Mariana Trench was formed by the collision of two large slabs of oceanic crust known as tectonic plates in a subduction zone, as per LiveScience.
A subduction zone occurs when one piece of oceanic crust is pushed and dragged into another, sinking into the Earth's mantle (the layer beneath the crust).
A deep trench arises above the bend in the sinking crust where the two pieces of crust join.
Under the Philippine crust, the Pacific Ocean crust is bending.
The Pacific crust is approximately 180 million years old when it enters the trench. The Pacific plate is older and smaller than the Philippine plate.
Despite its depth, the trench is not the location closest to the center of the Earth.
Plastic was the most common type of classifiable waste found in the database, with plastic bags being the most common source of plastic rubbish, as per the National Geographic.
Other debris included rubber, metal, wood, and fabric, and some have yet to be categorized.
A whopping 89% of the plastic was the sort that is used once and then discarded, such as a plastic water bottle or disposable utensil.
While the Mariana Trench appears to be a gloomy, lifeless abyss, it contains more life than you may believe.
In 2016, NOAA's Okeanos Explorer vessel explored the region's depths and discovered a variety of life forms, including coral, jellyfish, and octopus.
The latest research is only one of several that demonstrate how widespread plastic pollution has gotten throughout the planet.
Single-use plastics are nearly ubiquitous, and once in the environment, they may take hundreds of years or more to degrade.
Separate research published in February found that the Mariana Trench had greater levels of the total pollution in some areas than some of China's most contaminated rivers.
The authors of the researchers hypothesized that the chemical contaminants in the trench were caused in part by the decomposition of plastic in the water column.
Pollutants found in the trench
The deep ocean can function as a sink for dumped toxins and waste.
A research team led by experts at Newcastle University in the United Kingdom showed in a 2017 study published in the journal Nature Ecology and Evolution that human-made substances outlawed in the 1970s are still hiding in the deepest sections of the ocean.
The researchers observed unusually high levels of persistent organic pollutants (POPs) in the fatty tissues of amphipods (shrimp-like crustaceans) collected from the Mariana and Kermadec trenches.
According to research published in the journal Nature Ecology & Evolution, they included polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs), compounds routinely employed as electrical insulators and flame retardants.
From the 1930s until the 1970s, when they were eventually prohibited, these POPs were discharged into the environment through industrial mishaps and landfill leaks.
