Many people thought that it would be much peaceful and quiet at the bottom of the sea than on its surface. A team of scientists, however, explored the ocean to determine if this is indeed true. They found a cacophony of noises down some 36,000 feet.
Scientists from the Oregon State University, National Oceanic Atmospheric Administration (NOAA), and the U.S. Coast Guard surprisingly heard noises from both natural sources and humans when they expected to hear nothing but silence, calm and quiet. They heard everything from whales, marine animals, ship traffic and even earthquakes through the use of a titanium-encased hydrophone.
They used the device for about three weeks and it recorded various noises from the ocean's bottom in a trough called Challenger Deep in Mariana Trench, which is near Micronesia.
Quietest Place On Earth
Many, even scientists, believe that the bottom of the ocean is most peaceful part on Earth but according to their discovery, constant noise could be heard. This is the first time these sounds have been recorded.
"Yet there really is almost constant noise from both natural and man-made sources. The ambient sound field at Challenger Deep is dominated by the sound of earthquakes, both near and far was well as the distinct moans of baleen whales and the overwhelming clamor of a category 4 typhoon that just happened to pass overhead," said Robert Dziak, a NOAA research oceanographer.
They heard a lot of noises from ship traffic specifically from propellers since the area is near Guam, Philippines and China where there is widespread container shipping.
Recording The First Sounds Wasn't Easy
The Challenger Deep is one of the deepest waters in the world. It is about 7 miles below the ocean's surface and even if Mt. Everest would be placed at the bottom, its top still can't reach the surface.
Aside from that, the scientists faced the problem of tremendous pressure. The pressure in the bottom of the ocean is so incredible; it measures about 16,000 pounds per square inch. This is about 1,145 times higher than the average office or home atmospheric pressure.
The scientists dropped the hydrophone in July 2015 and it took about six hours for it to reach the ocean's bottom. Though it took more than three weeks for it to record sounds, the team needed to wait until November to recover it since the area is constantly hampered by typhoons.
They plan to return to Challenger Deep by 2017 to deploy the hydrophone. It will record sounds for a longer time and they plan to attach deep ocean cameras on it.
Ocean Noise Increasing
This project is the first one to establish a baseline for ambient noise in the deepest part of the Pacific Ocean. Noise in oceans grew over the past several decades. With a baseline data, the scientists will be able to determine how much these noises are growing.
Ocean noise has been increasing and many marine animals are affected. Ship noises hinder communication between animals in the ocean. Scientists found that endangered whales' ability to hear each other is hindered by ship noises. Underwater noise pollution poses a threat to many sea creatures.