The Noisiest Places in the Ocean are Next to 'Popping,' Melting Glaciers

Where are the noisiest places in the ocean? They're right next to glaciers, of course. Scientists have discovered that bubbles gushing from melting glaciers and their icebergs make fjords the noisiest places in the oceans.

"The ocean ambient sound gives us clues to the physical processes going on, but it also is an important aspect of the environment in which marine mammals and fish live," said Erin Pettit, one of the researchers, in a news release. "Like teenagers at a loud rock concert, the seals and whales modify their behavior depending on the ambient sound levels."

The scientists used underwater microphones to hear and record the average noise levels in three bays where glaciers flow into ocean fjords. These included Icy Bay, Alaska, Yakutat Bay, Alaska and Andvord Bay, Antarctica.

The researchers found that the average underwater noise level from bubbles in these fjords exceeded ocean noise levels generated by all other sources, including weather, the movement and communication of fish, and machines such as ships and sonar devices. In fact, the sound waves were measured at frequencies between 300 and 20,000 Hertz, which covers most of the average human's hearing range.

While glacial calving was loud, the noise was short-lived. Overall noise levels can be blamed on the consistent melting of ice from the glaciers and their icebergs. Air trapped within the glacier ice escaped rapidly as it melted into saltwater, forming bubbles that then popped and formed noise.

As glaciers continue to melt, the findings raise question about how underwater noise in fjords will affect animals. Glacier melt rate is increasing with climate change, which means that the seas may be becoming noisier places in the future.

The researchers plan to continue listening to glaciers to see if they can develop a method of predicting glacier melt based on underwater sounds.

The findings are published in the journal Geophysical Research Letters.

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