Posted by: kaleidophonic | March 8, 2012

Noise Pollution

Noise pollution.

It’s something we’ve all experienced, from the constant hum of traffic noise in the cities, to the scream of airplane engines over the suburbs, to the racket generated by a neighbour’s gas-powered leaf-blower.

It was even the subject of a recent article in one of Montreal’s transit-dailies, 24-H. According to this article, noise complaints last year in Montreal can be broken down into the following categories:

29 % : Mechanical equipment such as industrial air-conditioning or heating units.

27 % : Construction sites.

24 % : Outdoor events such as concerts or festivals.

14 % : People blasting loud music.

6 % : Other.

Its a well-established fact that noise pollution is unpleasant. It definitely causes people stress, and health officials are well aware that constant exposure to noise contributes to numerous negative health conditions such as chronic anxiety, irritability, sleeplessness, lack of concentration, depression, high blood pressure, and of course hearing impairment. Fun!

This probably isn’t news to any of you. We all live in a modern industrial society, and along with this comes a plethora of modern industrial noises. (Indeed, that’s why soundproofing was invented. For more about this, check out my blog post on Emily Thompson’s book The Soundscape of Modernity).

Modernity is noisy. Along with all the other kinds of pollution that we’ve created — air pollution, water pollution, soil pollution, light pollution — noise pollution is right there too. But if you think these other kinds of pollution are the only ones having a negative impact on our natural environment, think again.

The following is from an article written by Helen Fields at ScienceNow.

“Shhh… Ocean Noises Stress Out Whales”.

Scientists have long wondered whether propeller and engine noises from big ships stress whales out. Now, thanks to a poop-sniffing dog and an accidental experiment born of a national tragedy, they may finally have their answer.

Baleen whales use low-frequency sounds to communicate in the ocean. “They’re in an environment where there’s not a lot of light; they’re underwater. They can’t rely on eyesight like we do,” says veterinarian Roz Rolland of the New England Aquarium in Boston. Some studies have found that whales alter their behavior and vocalizations when noise increases, and it stands to reason, she says, that noise pollution would hinder their ability to communicate and cause them stress. But because scientists can’t control the amount of noise in the sea, that’s been very hard to prove.

Researchers couldn’t stop traffic, but the September 2001 terrorist attacks did.

At the time, Rolland was collecting feces of right whales in the Bay of Fundy in Canada so she could try to develop pregnancy tests and other ways to study the animals’ reproduction.

Animals break up their hormones and get rid of the leftovers in their poop, so feces can show whether an animal is pregnant and reveal its levels of stress. Blood samples would do the same, but feces are much easier to collect.

In the first few days after the terrorist attacks, ship traffic in the region decreased dramatically. “There was nobody else there. It was like being on the primal ocean,” Rolland says. The whales seem to have noticed the difference, too. The levels of stress hormones in their feces went down, suggesting that ship noise places whales chronically under strain.

Rolland and colleagues made the finding with the help of an extremely sophisticated poop detector: a dog’s nose. The dog—most often a Rottweiler named Fargo—stood at the prow of a research vessel, sniffing as the boat moved across the water. “You use the dog’s nose as a compass because the dog will always put his nose into the strongest scent,” Rolland says.

[…]

While Rolland’s team was collecting feces, other scientists, including biologist Susan Parks of Syracuse University in New York, were recording sounds in the Bay of Fundy to understand right whale behavior. But it was only in 2009, when Rolland was preparing for a workshop on noise and cetaceans convened by the U.S. Office of Naval Research that she realized she could combine the two data sets. She and her colleagues compared poop and noise measurements collected between 2001 and 2005.

The only year when whales’ stress hormones decreased was 2001, when noise and ship traffic also decreased. Overall noise decreased by 6 decibels, with a particular reduction in low-frequency noise, the sounds that right whales are thought to care about the most. Only three large ships passed by the right whales on 12 and 13 September 2001, compared with nine on 25 and 29 August (2 days when recordings were made).

Stress can interfere with the immune system and with reproduction. There are only 475 right whales in the western North Atlantic Ocean, and they have much lower reproduction rates than right whales that summer near Antarctica. Stress caused by noise could be part of the reason, the team reports online today in the Proceedings of the Royal Society B.

“I’m quite surprised that they saw such a large difference,” says Michael Romero, an endocrinologist at Tufts University in Medford, Massachusetts, who studies stress in birds, Galápagos marine iguanas, and other animals. Some of his research has suggested that animals get used to disturbances over time and have lower stress hormone levels. “It’s a terrific paper. They were able to do something that really it’s difficult to imagine repeating, which is keeping boats silent for a fairly reasonable period of time,” he says.

Since the experiment was unintentional, the scientists couldn’t control it as well as they might have liked. They didn’t have sound levels from before 2001, for example. Still, Rolland says the findings are cause for worry. “The big message is that there’s enough noise in the oceans that we should be concerned,” Rolland says. There may be ways to build quieter ships, but oil and gas exploration, wind farms, and sonar also emit the low-frequency sounds that seem to particularly bother whales. “It’s sort of like dumping all of our solid waste and sewage into the ocean,” she says. “There’s a certain point at which people realize the oceans aren’t limitless and they can’t absorb all this we’re dumping into them, and I think we’re reaching that realization with noise.”

Clearly noise pollution is a problem affecting not only the human inhabitants of this planet, but other species as well. And when noise pollution gets less media attention than other forms of pollution, it sounds like this is a problem that isn’t going to go away any time soon…

So let’s all make an effort to tread a little less loudly on our planet, shall we?  Shhh! Don’t stress out the whales!

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