The Deepest, Darkest Place on Earth Is Eerily Noisy

By Nathaniel Scharping | March 4, 2016 12:50 pm

Credit: NOAA

If you’re looking for some peace and quiet, you certainly won’t find it at the bottom of the ocean.

Scientists from the NOAA have released audio recordings taken from the Mariana Trench, the deepest part of the ocean. Even here, sounds from humans, animals and even the earth itself eerily echo in the dark.

Researchers sunk a specialized probe, called a hydrophone, almost 36,000 feet into the Challenger Deep at the Mariana Trench in an effort to establish a baseline for oceanic noise. They were expecting to capture nothing more than a vast, echoing silence, given the extreme remoteness of their testing site. Instead, over the course of 23 days, they were able to capture whale calls, ship propellers, earthquakes, and even the sound of a Category 4 typhoon passing by overhead. In the recording below, you can hear a baleen whale calling, followed by a magnitude 5 earthquake that occurred July 16, 2015.

Sound Goes On and On

Sound waves travel around five times faster through water than through the air, and have to deal with fewer disturbances and obstacles. For this reason, sounds underwater can travel much further than sounds up above. Whales are known to communicate over long distances using low-pitched grunts and moans, and they could likely be heard up to 1,000 miles away before the days of ship traffic and noise pollution in the oceans.

The prevalence of noise pollution today is one of the main reasons the NOAA scientists are conducting the study. The increasing din of human activity in the ocean, caused by ship propellers and sonar, has been linked to disruptions in whale and other marine wildlife behavior. The researchers want to establish a baseline of sound in the ocean today in order to measure changes in the future. At the bottom of the Mariana Trench, researchers set up their hydrophone as far away from any disturbances as possible.

The researchers had to create a special probe capable of withstanding the crushing pressure seven miles below the surface. They then had to lower the titanium-covered ceramic probe with extreme caution, at a sedate 16 feet per second, to allow it to acclimatize to the harsh conditions.

The researchers plan to return in 2017 to make more measurements and see if noise levels have increased.

CATEGORIZED UNDER: Environment, top posts
MORE ABOUT: ocean, pollution
  • Don’t Even Try It!

    Oh great!!! I can just hear it now…”We must use wind power so we don’t upset the poor little fishes!”

    • Lee Riffee

      Actually wind turbines can be incredibly noisy, so that would likely only add to the din…

      • Golfinator

        He’s most likely referring to wind on sails.

      • Rob Neff

        I’ve stood underneath turbines, and they give a bit of a wooshing noise, but it doesn’t travel very far (maybe 100 feet from the base). And noises from the atmosphere wouldn’t go into the water anyway.

  • 1064nm

    What is “echoing” silence?

    • Don Huntington

      I know what it means. Absolute silence has a flat quality but in a vast cathedral or cave, the silence has a ringing, echoing quality. All of us have experienced this.

      • 1064nm

        Good point. Thanks.

      • Janardhan

        You are right. It is the sound of silence.

  • Small_Businessman

    So how many dbm are we talking about here?

  • KonradAjster

    Zelo zanimiva odkritja, a katerih je
    verjetno še več, saj naš Zemeljski svet je za znanost še velika uganka, ker
    niso še odkrili temelnega zakona snovi, od kjer je možno spoznavanje vsega in
    vesolja, toda znanstveniki so šli raziskovati v vesolje, kjer je ugank
    preveliko, ko pa so same osnove naravnih energijskih zakonov, ki jih lahko
    odkrijejo kjer koli na Zemlji zanemarili pa čeprav bi bil na ta način njihov uspeh
    raziskovanja veliko hitrejši in večji!

  • Van Snyder

    What is echoing silence?

    • The Doctor

      I’m guessing the ambient sound of the Earth.

    • Don Huntington

      (As I wrote below…) Absolute silence has a flat quality but in a vast cathedral or cave, the silence has a ringing, echoing quality. All of us have experienced this.

  • Kehvan

    Those pansy whales need some toughening up… If they can’t handle some propeller noise, how are they ever going to handle sentience reasonably and responsibly?

    • Don Huntington

      Wonderful! Thanks!

  • onyoursix33

    How many gallons of fossil fuels were spent doing this?

    How long was this test? Will the next be at the same time of year under the same weather conditions?

    Must be nice to have someone pay the bills on this, only hope they use sound testing methods.


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