A Quiet Ocean

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Leonardo da Vinci once wrote, “If you cause your ship to stop, and place the head of a long tube in the water, and place the other extremity to your ear you will hear ships at a great distance from you.” His description is quite accurate of sea water’s ability to transmit sound easily. In a quiet ocean, the whale’s song (at up to 190 dB) can be heard from one continent to another. But quiet oceans do not exist anymore. In fact, they began disappearing the moment humanity became a seafaring race.

A marine biologist listening to the sounds from an underwater microphone.
Credit: Steve Jurvetson

There are many issues that acoustic smog is causing to sea life, whales being among the most well known. Sonar has been linked to causing whales to beach themselves. A naval exercise in 2002 caused many whales to beach with hemorrhaging in their ears and lungs. The sound of sonar has also been shown to wreck the balancing systems of squids and octopodes, meaning they become unable to move. Boat engines produce noise in the same band of sound as many fish communication frequencies, meaning fish may have difficulty communicating.

One of the beached whales at the Canary Islands in 2002

But there is still much to be learned about man-made (or anthropogenic) sounds’ effect on sea life. So how do we learn more? One answer is the International Quiet Ocean Experiment. Just as stated, the goal of the project is to study what differences a quiet ocean would have on sea life. Organizers hope to coordinate a single day in which most (though ideally all) anthropogenic ocean noise is turned off. It is no easy task, but already one study has achieved this the day after the 9/11 attacks (when all commercial transport was halted). The study showed that whales had less stress hormones during that period.

Noise levels in days before and after 9/11/2001.
Credit: Proceedings of the Royal Society B

With so much noise today, including seismic tests and military operations, how does the IQOE plan to move forward? Admittedly, the ultimate hope seems futile. Somehow convincing all nations to halt their ocean noise simultaneously can be a preposterous thought. Unfortunately, no solutions have arisen, but that hasn’t stopped the group from conducting research anyhow. There’s a lot to be learned.

Music: Miroirs – III. Une barque sur l’ocean by Maurice Ravel performed by Robert Ewen Birchall