Quirks & Quarks

An ocean of noise is having major impacts on the marine environment

Ocean acidification from greenhouse gases, noise pollution are making it harder for marine species to hear

Scientists say noise pollution is 'the neglected elephant in the room of global ocean change'

Melting ice in the Arctic due to climate change is opening up new passages for large ships and icebreakers to travel through, which will increase noise pollution in the area. (Kirill Kudryavtsev/AFP/Getty Images)

Human pollution is changing the way sound works in the ocean, muffling out natural sounds marine marine animals use to mate, communicate and navigate.

There are two ways this is happening. 

According to a new study in the journal Proceedings of the Royal Society B, ocean acidification — caused by ocean waters taking up excess carbon dioxide from fossil fuel emissions — may be making it more difficult for fish to hear.

Michelle Havlik, a PhD candidate at King Abdullah University of Science and Technology in Saudi Arabia, dives in the Red Sea with an aquatic speaker during a research expedition. (Michelle Havlik)

Craig Radford, an associate professor of marine sciences at the University of Auckland in New Zealand, is the lead author of the study. He found the more acidic the water is that the fish grew up in, the worse its hearing becomes. 

That means the juvenile snapper fish he studied that spawn out in the ocean might not be able to find their way back to the reef if they can't hear as well. 

The snapper’s hearing bones, known as otoliths, grew larger under increased ocean acidification conditions and became less symmetrical, which results in the fish not being able to hear lower frequency sounds as well. (Craig Radford / University of Auckland)

And at the same time the ocean environment is becoming a noisier and more difficult environment in which to hear, largely due to human noise pollution.

Humans produce a vast amount of ocean noise, from sources like commercial shipping, navy sonar activity and seismic oil, gas and geological exploration. 

Conservationists say the endangered southern resident killer whales will be further affected if the navy is allowed to fire torpedoes, deploy sonar and detonate bombs at sea. (file) (Elaine Thompson/The Associated Press)

In a recent review paper in the journal Science, marine scientists called for urgent international action to curb underwater noise pollution, which they wrote has become "the neglected elephant in the room of global ocean change." 

Francis Juanes, the Liber Ero Chair for Fisheries Research at the University of Victoria in British Columbia and senior author of the paper, described the extent of the "soundscape of the anthropocene ocean" — as they call it in their paper.

Researchers studying how endangered North Atlantic right whales found that when they're exposed to higher noise levels, they actually call louder. (NOAA/NMFS Permit #17355)

He said the volume of shipping noise alone has increased 32-fold in the last 50 years. 

You can listen to ocean soundscape and interviews with Craig Radford and Francis Juanes, at the link above.

Produced and written by Sonya Buyting

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