Science·What on Earth?

Sound experiments capture 'pernicious' impact of noise pollution on wildlife

In this week's issue of our environment newsletter, we look at how noise pollution affects wildlife and why climate experts are debating the idea of naming heat waves.

Also: Is there an advantage to naming heat waves?

(Sködt McNalty/CBC)

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This week:

  • Sound experiments capture 'pernicious' impact of noise pollution on wildlife
  • Should we give names to different heat waves?
  • 'Nature's own artwork': Conservationists worry about destruction of B.C.'s rare glass sponge reefs

Sound experiments capture 'pernicious' impact of noise pollution on wildlife

(Jeremy Price)

An emerging form of research is yielding fascinating insights into the effects of human noise pollution on the natural world.

One example is a project by then-University of Manitoba PhD student Patricia Rosa, who distributed speaker systems across a large swath of rolling prairie outside the town of Brooks, Alta., an oil and gas industry hotbed.

From 2013 to 2015, the speakers blasted a range of sounds produced by an operating oil well — from the continuous humming of a dipping pump jack to the short, sharp bursts of clanging pipes.

The speakers ran around the clock for months at a time to produce an industrial soundscape that overlapped the breeding season of multiple at-risk species of grassland songbirds.

Published last October, Rosa's work found that noise pollution from the oil and gas industry, especially acute drilling sounds, reduced the abundance and reproductive success of multiple bird species (such as the savannah sparrow, above).

Now a professor of biology at St. George's University in Grenada, Rosa said her study captured factors she may have overlooked had she worked on a smaller scale.

The effects of noise can be difficult to separate from a range of other disturbances in nature because noise "permeates into habitats," said Graeme Shannon, a lecturer in animal behaviour at Bangor University in Wales.

"There is no boundary for noise, as such. It doesn't end where the roadway ends," he said. "It's a very pernicious form of pollution."

Landscape sound experiments like Rosa's try to tease out the role of noise over large swaths of land.

Early research on noise pollution focused on human health, Shannon said, and found links between noise exposure and health impacts ranging from cardiovascular disease to sleep deprivation to cognitive function.

Sometime in the early 2000s, he said, the scope shifted to include wildlife. The studies that came next were small and focused on one species at a time — or one behaviour. But recent work is zooming out to capture the bigger picture.

"We needed more controlled experiments that looked at the effects of chronic noise exposure across the landscape," he said.

Large experiments allow researchers to capture the "full intricacy of the system," said Boise State University biology professor Jesse Barber.

In his own research, Barber's large sound experiments include a "phantom road" built through the forests of Idaho. The setup replicated highway noise pollution by playing recorded traffic sounds through a series of speakers mounted on towering Douglas fir trees.

"We were building a highway — acoustically," Barber said.

Even without the disruption of traffic or asphalt, many nearby migratory bird species struggled to put on weight or were forced to avoid the area altogether.

The negative effects on birds don't stop there, said Clinton Francis, an ecology professor at California Polytechnic State University.

"[Sound] influences their overall reproductive success, influences their stress hormone profiles, changes patterns of predation pressure, changes patterns of seed dispersal and pollination by hummingbirds," he said.

With so many well-documented harms, Francis and others have recently approached the issue in reverse — how does exposure to natural sound benefit human health?

In a study conducted in the redwood forests of the Muir Woods National Monument north of San Francisco, hikers said they enjoyed the park more when signage reminded other visitors to keep their sound to a minimum — and allow the natural soundscape to ring clearer.

That ability to limit human sound without the need for an expensive or technical intervention, Shannon said, is something of a silver lining when it comes to noise pollution.

"The great thing about noise," he said, is "you can switch it off."

Benjamin Andrews

Reader feedback

James Foley:

"I just read the article on floating solar installations and their lack of use in Canada. Reading about the issue of land use taken up by solar, I'm continuously amazed at the most obvious location to place solar installations. All across the country are large areas of cleared land running between cities designed for the sole purpose of carrying electricity. Hydro corridors are everywhere, with a large, 100-metre swath of cleared space directly underneath them. Space that is regularly brushed to keep vegetation down. One would think lining these spaces with solar panels is a no-brainer. Apparently that isn't the case, as there are no panels to be found in them. The space is there, the infrastructure is there. Someone just needs to put two and two together."

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The Big Picture: The debate over naming heat waves

As record heat waves sweep across North America and Europe, a new international project is experimenting with naming them to increase public awareness of their severity. The Adrienne Arsht Rockefeller Foundation Resilience Center, a Washington, D.C.-based group studying climate resiliency, is running a pilot program to see whether a naming system for heat waves will affect the public's perception — and actions — during periods of intense heat. 

"Heat, unlike other natural disasters, is silent and often not seen. Therefore, it's extra important that we raise awareness around what heat can do, because it's actually one of the deadliest natural disasters that we face," said Kurt Shickman, director of extreme heat initiatives at the centre. The program launched in six cities, including Los Angeles, Miami, Milwaukee and Kansas City, Mo., as well as Seville, Spain, and Athens, Greece. In July, Seville (pictured below) was the first city in the world to name a heat wave, calling it Zoe, according to Shickman. 

The World Meteorological Organization (WMO), a United Nations agency, said it is supportive of classifying heat waves but isn't certain how naming them works scientifically. The WMO also questioned whether the system could be confusing for the public. In Canada, some researchers agree with the WMO and are skeptical of how a naming system will communicate the severity of heat waves. 

"I'm really, really against it. I think that hearing, you know, that heat wave Zoe or Joey is about to come your way — it doesn't really drive fear in my heart," said climatologist David Phillips, a long-time researcher with Environment Canada, who was sharing his personal view with the CBC. 

He also pointed out that the reason a naming system was developed for tropical storms was for clear communication. Multiple storms can be happening in close proximity, or have the potential to collide. Heat waves are also difficult to define and measure, said Phillips. 

"In a tropical storm, one element decides whether it'll be a tropical storm, or a category 1, 2, 3, 4 or 5 hurricane — it's the sustained wind. It's scientific, it's measured," said Phillips. But with heat waves, "I just think there's so many weather elements that make it up."

Sarah Williscraft

People use a public fountain to cool down.
(Jorge Guerrero/AFP via Getty Images)

Hot and bothered: Provocative ideas from around the web

  • A new study suggests that by mid-century, there will be an "extreme heat belt" in the U.S. between Texas and Illinois in which the heat index will hit 51 C (125 F) at least once a year.

  • This week, U.S. President Joe Biden signed a climate bill. Given the country's spending power and clout, it should have large implications for global climate action. Activists say the U.S. Senate could build on that success by ratifying the Kigali Agreement, a worldwide pact to phase out hydrofluorocarbons (which are powerful greenhouse gases used in refrigeration and air conditioning). Researchers say this move alone could avoid as much as half a degree Celsius of global warming by 2050.


'Nature's own artwork': Conservationists worry about destruction of B.C.'s rare glass sponge reefs

(Submitted by Glen Dennison)

Every time he heads out on the waters in Howe Sound outside of West Vancouver, Glen Dennison worries about the health of the prehistoric creatures he found nearby.

"I discovered them — so, you know, right away, they're my children," Dennison said with a laugh on his small boat, referring to the rare glass sponge reefs below. 

Dennison was writing a book on diving in Howe Sound in 1984 when he made a significant discovery of massive glass sponge reefs. They look like something from another world, with beige and brown tubes delicately intertwining as fish dart between them. 

While individual glass sponges are not uncommon, scientists believed that reefs of them — also known as bioherms — had gone extinct 40 million years ago. "When I saw it, I was totally amazed. I didn't understand what I was looking at," said Dennison. "It's nature's own artwork."

Not only are these sponges rare, scientists say they contribute to the health of the Howe Sound. "They filter the water, roughly every 90 days," Dennison said. "They're bacteria feeders, they're habitat for the rockfish here."

But their fragility leaves them susceptible to damage from commercial and recreational fishing. Given that they are made of silica, the main component of glass, the reefs are like delicate crystal. They can be instantly shattered by things like crab and prawn traps, anchors, fishing line and downriggers.

Dennison's accidental discovery launched a decades-long fight to protect the reefs, with Dennison almost single-handedly funding most of the dives to document them. He used his skills as an engineer to create a special camera that can be dropped down to capture live images of the reefs and map every inch of them.

His work helped push the Department of Fisheries and Oceans (DFO, now called Fisheries and Oceans Canada) to put protections in place banning bottom-contact fishing — that is, any activities that make contact with the bottom of the ocean, including dropping traps or downriggers. 

Dennison, now president of the Marine Life Sanctuaries Society, says it isn't uncommon to find new damage.

"The DFO enforcement officers are doing the best job they possibly can out there," Dennison said. "But they are so short-staffed that they just cannot protect the sound properly."

The Department of Fisheries and Oceans says it patrols regularly. After the initial protections were put in place, it says infractions dropped dramatically. But Fisheries officer Eric Jean says the pandemic brought a whole new group of people on the water, and infractions jumped.

"There was a whole new cohort of individuals that are playing and recreating in these areas and perhaps under the guise they don't know reefs are there," Jean said, noting that new legislation from April 2021 created higher fines and potential bans for recreational and commercial fishers. 

But Dennison says more enforcement and education is needed.

"You can't wait till someone drops a trap down there and hope that you're going to give them a ticket or take away their gear," he said. "The reefs will be gone."

While bottom-contact fishing is banned, many of the reefs do not ban dropping anchor, an issue DFO said was up to Transport Canada. In statements to CBC, Transport Canada said, "Anchoring has long been recognized as accessory to the common law public right of navigation. While Transport Canada has not legally prohibited anchoring in these areas, in practice there are no commercial anchorage sites."

A statement also said, "Operators of recreational boats who may be laying anchor over reefs should seek local information found in marinas on the area in which they will be navigating."

Something else is also threatening the reefs' survival: climate change. Researcher Angela Stevenson is one of the only people who has been able to maintain small sponges in an aquarium to study the effects. She said warmer and more acidic water reduces the ability of the sponges to filter water and ultimately damages them. 

"It means they're filtering a lot less of the microbes and the particles in the water," she said. In her research she found that in warmer water "they could withstand less pressure. So they broke more easily."

Dennison worries about this. 

If the reef is "damaged or destroyed, it may not come back," he said. "We don't have the science yet to prove that these things are going to regenerate again. They may actually disappear off the planet."

Susana da Silva

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Editor: Andre Mayer | Logo design: Sködt McNalty

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