Here in New York City, noise aggravations surpass even rodents and blocked driveways as the top complaints phoned in to the city's 311 help line. According to the European Environment Agency, the psychological and physical harms caused by unwanted "environmental noise" can range from annoyance and lost sleep to cardiovascular illness.
So it's not hard to imagine that life is becoming uncomfortable for fish, whales, and other undersea creatures as well, as an increasing volume of human-caused "acoustic smog" creates a health-threatening din beneath the waves. Caused chiefly by commercial shipping vessels, this noise may be preventing some animals from finding each other, whether the reason is to mate or to eat.
In response to the underwater racket, researchers say, some North Atlantic right whales may be turning up the volume of their "upcalls": second-long whoops that start deeply pitched and rise. Making upcalls to other nearby whales is the right whale's way of saying, "Yo! This whale is in the house."
To learn more about how right whales are coping with the acoustic smog, a team of marine scientists gathered recordings of upcalls by attaching recording devices called "D-tags" to individual whales in the Bay of Fundy. From the resulting audio records, made over three summers between 2001 and 2005, they analyzed 18 upcalls from 14 different whales, finding that when the ambient noise level increased, each of the whales upcalled more loudly by about 10 to 12 decibels.
Analyzing these recordings against earlier data suggests that the whales are trying to adapt to their changing environment. Marine biologist Susan Parks, the lead researcher, "found that whales recorded in the 2000s started their upcalls at a frequency between 100 and 200 Hertz (roughly an octave below middle C). By contrast, in recordings made in the 1950s by WHOI whale song pioneers Bill Watkins and Bill Schevill, right whale upcalls started about an octave lower, at 50 to 100 Hertz," wrote Cherie Winner in Oceanus, the magazine of the Woods Hole Oceanographic Institutution.
But how long will they keep it up? There are only around 300-400 North Atlantic right whales left, despite a whaling ban established in 1937 (after centuries of intense hunting). The increasing noise pollution may be making it even harder for these few remaining right whales to find each other across their vast habitat.
Ocean acidification, the flip side of human-propelled climate change, further compounds the noise problem. As CO2 increases in the atmosphere, the ocean absorbs more of it--enough, at this point, to begin shifting the acid-base chemical balance of sea water. As the balance changes, some pH-sensitive, sound-absorbing compounds in the sea are decreasing, which may eventually contribute to undersea noise levels becoming even louder.
So far it seems that North Atlantic right whales want to find each other, and will yell to do it. But there are no regulations mandating a reduction in noise pollution from container ships, or much movement toward effective international treaty to reduce the atmospheric carbon pollution that is changing the ocean's chemistry. Perhaps the right whales, like New Yorkers, need a 311 help line where they can register their noise complaints.
Image: North Atlantic right whales. Credit: NOAA
