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What’s the Deal With Ocean Noise?

Emily Heaslip

There weren’t many silver linings to be found as a result of last year’s global pandemic. But, if anything benefitted from COVID-19, it was the environment. A recent study found that the pandemic led to better air quality, a reduction in GHGs, and less water pollution while humans stayed indoors and the global economy slowed. 

Marine life, in particular, benefitted from less human activity over the last year. As ocean travel slowed, the seas became not only less polluted but also “quieter.” Ocean noise affects whales, dolphins, and other marine organisms that rely on sound to mate, hunt, and navigate. And, despite the pandemic, ocean noise has steadily been getting worse. Here’s what causes ocean noise and how to reduce noise in the ocean. 

What is ocean noise?

Ocean noise is defined by NOAA as “sounds made by human activities that can interfere with or obscure the ability of marine animals to hear natural sounds in the ocean.” 

Primarily, ocean noise comes from human activities related to the oil and gas industry, the shipping industry, and military activity around the world. In some regions, experts estimate that levels of ocean noise have doubled every decade for the last 60 years. Some of the sources of marine noise pollution include: 

  1. Seismic airguns: These devices are used primarily to explore the ocean floor for oil and gas, as well as to take geophysical surveys. 
  2. Military sonar: Mid- and low-frequency sonar systems are used by military vessels to search for objects such as enemy submarines in training sessions and regular defense drills. 
  3. Shipping and logistics traffic: The shipping industry accounts for the majority of noise in the ocean. Vessels produce low-frequency (10Hz - 1kHz) sounds that can “mask” natural sounds. 
  4. Explosives: There are a surprising number of explosives being used at sea. “Explosives are detonated in the ocean by the military, for demolition purposes, or for testing equipment – e.g., ship-shock trials, whereby ships are deliberately struck with explosives to test their durability,” writes Ocean Care.
  5. Construction: Oil rigs, offshore energy farms, and construction in harbors all increase noise levels in the ocean. 

The pandemic may have led to a temporary dip in underwater noise pollution, but the fact remains that our oceans are noisier than ever: Underwater noise pollution from shipping activities, military operations, and even fishing has increased consistently over the last 100 years

It’s often difficult to get support for this issue because humans don’t live with this level of sound in their day-to-day lives. What does a noisy ocean sound like? Imagine living in a never-ending construction site. Only, instead of being a mere annoyance, the sound interferes with your ability to walk, date, and find food.

The artist Jana Winderen created a six-minute track that begins with the sounds of a healthy ocean and ends with the sounds of noise pollution. Listen here: 

What does ocean noise mean for marine life? 

Underwater noise pollution impacts virtually every animal that lives underwater, including crustaceans, dolphins, fish, seals, sea turtles, and whales. 

“Ocean noise dramatically changes an animal’s behavior. It causes stress and drives the animal out of its habitat. It reduces an animal’s ability to communicate, navigate, locate prey, avoid predators, and find mates. All the aspects of an animal’s life is disrupted by human-produced ocean noise. In the worst cases, it can lead to physical injuries and even death following long, loud impact,” wrote the IFAW

Many animals have exhibited adaptations to cope with the dangers of a noisy ocean. Some move to avoid shipping lanes; others change habitats completely. Dolphins have been shown to change the way they communicate due to ship noise. Because many ship noises were within bottlenose dolphin call bandwidth, dolphins began communicating at higher frequencies and with less complexity. 

“Consequently, the noise-induced simplification of dolphin whistles may reduce the information content in these acoustic signals and decrease effective communication, parent–offspring proximity or group cohesion,” found the study

Some animals aren’t so adaptive. A study of baby clownfish found that noise can prevent them from finding their way home, dooming them to wander the seas. Finding Nemo, but much darker. 

The good news? There are steps we can take to help reduce noise pollution in the oceans. 

How to reduce noise pollution in the ocean

There are concrete, simple solutions that we can take to reduce noise pollution in the ocean. A good place to start? The shipping industry. 

“Slow down, move the shipping lane, avoid sensitive areas, change propellers,” Steve Simpson, a marine biologist at the University of Exeter told The New York Times

The most common ship propellers cause a great deal of noise from tiny bubbles that form around the propeller blade. However, there are more options that are much quieter. Likewise, something called a “bubble curtain” can be wrapped around a pile driver to insulate sound and lessen noise from construction and oil & gas exploration. 

In addition, slowing the speed of ships can help reduce the noise they make en route to their destination. Tools like Sofar Ocean’s Wayfinder provide a way for ships to find the most optimal route at a given speed, helping vessel operators save fuel, reduce speed, and still achieve business results. For instance, Wayfinder can help a vessel operator dynamically manage the speed and heading of a ship to avoid disturbing sensitive environments with noise pollution.  This might include routing ships at a wider berth around islands and subsurface reefs. Traveling at a slower pace can also help save fuel costs and make progress towards decarbonization targets

Ocean noise doesn’t get a lot of attention, but it’s seriously damaging marine ecosystems and hurting animals. And, the good news is that there are relatively easy ways to make the ocean quieter. Learn more about Sofar’s Wayfinder product and what we’re doing to help the shipping industry become more environmentally-friendly. 

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