- Shipping Noise Doubles Every Decade, Impacting Whales and Dolphins.
- Marine Species Struggle as Underwater Noise Reduces Communication Range.
- Startup Develops Noise-Cancelling Technology for Ships.
Noise levels in the world’s oceans are constantly increasing due to industrial and military activities, with shipping being the largest source. Marine traffic has led to an increase in noise levels by around three decibels per decade, doubling the intensity of the sound. This increased noise pollution creates a major threat to marine animals like whales and dolphins, which use sound for vital life activities, including navigation, communication, mating, and feeding, reports CBC.
Impact on Marine Animals
“Every time … background noise is louder, then whales’ communication range is shrunk by an exponential component, so what used to be maybe half the ocean that they could hear over…has now shrunk to a pinprick,” said Lindy Weilgart, senior ocean policy consultant for the NGO OceanCare and adjunct professor at Dalhousie University in Halifax.
“This causes other factors such as stress increases, and stress is very dangerous over the long term.” Other marine life also suffer the effects of sound, said Weilgart. “This is a cross-species effect as well as a wide-ranging effect because sound can travel thousands of kilometres underwater.”
Shipping: A Major Source of Ocean Noise
Most shipping noise comes from the operation of propellers, engines, and generators. Propellers create a phenomenon called cavitation, where pressure differences cause bubbles to form and burst, producing loud noises. “The hull of a ship acts like a big speaker, a big radiator of noise,” explained Paul Hines, chief technical officer at Rising Tide BioAcoustics.
Noise-Cancelling Systems for Ships
A noise-cancelling system that works like the popular noise-cancelling headphones is in development by Rising Tide BioAcoustics in Dartmouth, N.S. It uses underwater microphones to detect ship-generated noise and deploys algorithms to create sound waves that cancel those noises.
“The game-changing part was being able to make very loud, low-frequency sounds that can be used to cancel the ship noise because projectors are much smaller than they used to be,” said Hines. In partnership with Geospectrum Technologies, the startup has used advanced low-frequency projectors to build a prototype system that has shown promising results.
AI for Noise Monitoring in Ports
Another challenge is to understand the level of underwater noise pollution. To address this, a New Brunswick-based startup, SeafarerAI, is using artificial intelligence. The company’s system utilizes hydrophones to capture underwater sounds and algorithms to categorize them.
CEO Ian Wilms said as governments and agencies look to address underwater noise, there’s a need for ports to get a handle on the issue. “There’s basically zero technology under the water being used in the majority of ports. It’s just not a focus area.”
Dual-Benefit Solutions
Other technologies address noise and environmental issues together. GIT Coatings of Dartmouth has developed a hull coating that reduces drag and biofouling, thus leading to lower greenhouse gas emissions and less noise pollution.
Simple Measures and the Need for Regulation
Weilgart emphasized that small changes, such as reducing ship speeds, can have a significant impact. “A 10 per cent reduction in speed reduces the area polluted by sound by 40 per cent,” she noted. Additionally, ships designed for better fuel efficiency are often quieter, providing another avenue for reducing underwater noise.
While noise pollution is gaining attention, it still lags behind greenhouse gas emissions in priority. “We care more about greenhouse gases and climate breakdown than noise, even though noise is an important issue,” Weilgart observed. She advocates for solutions that address both issues simultaneously, as well as the introduction of binding regulations to encourage innovation.
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Source: CBC
