The air-guns fire every 16 seconds — sometimes for hours, sometimes for days. The blasts can reach as loud as 180 decibels, 40 decibels greater than what you would experience mere meters away from a jet engine. Unlike a jet engine, however, the guns are towed behind seafaring ships and fired into the water, where sound travels much further and more effectively than it does through the air.
The blasts rocket into the sea floor, reverberating off subterranean structures and echoing back to the surface, where they are recorded by hydrophones trailing behind the guns. Along their way, they bruise the internal organs of nearby sea life, deafen fish, deplete breeding stock and send whales careening onto beaches. The data collected from these seismic surveys will be used to identify potentially lucrative pockets of oil and gas — those that will maximize the return on an expensive investment in drilling equipment and personnel. Thus pollution begets pollution, noise begets noise.
The effects of firing giant sound cannons into the ocean are severe, but seismic surveys are not currently classified as noise pollution. But a group of scientists writing in the journal Frontiers in Ecology and the Environment has recently called for this distinction — and for the creation of a new regulatory body to mitigate its consequences.
According to the Natural Resources Defense Counsel (NRDC), “a single seismic survey can cause endangered fin and humpback whales to stop vocalizing — a behavior essential to breeding and foraging — over an area at least 100,000 square nautical miles in size.” The blasts also muffle lower-frequency calls made by other species of whale and tends to drive out all manner of marine life from wide swaths of territory, separating hungry animals from their food, alienating mothers from their calves and diminishing the biodiversity essential to healthy ecosystems.
“Imagine an explosion going off in your neighborhood every ten or 12 seconds,” Michael Jasny, senior policy analyst at the NRDC, told Van Winkle’s. “Now imagine it going off every ten or 12 seconds for days, weeks, and months on end. Now imagine that...that hearing is your primary sense. That’s what this is.”
In some cases, the damage is immediate and brutal. Newsweek notes that beaked whales might be more sensitive to sound than any other cetacean. When subjected to oppressively loud noise, they “dive recklessly” and often die from the bends. In one particularly gruesome case, researchers discovered 13 beaked whale carcasses on a beach in the northern Bahamas. The whales’ heads were sent to a lab in Boston, where CAT scans “revealed unmistakeable evidence of acoustic trauma.”
Other studies focusing on snow crabs (a common item in the frozen-foods aisle) show they, too, suffer from the air-gun’s blast. They turn up with “bruised organs, abnormal ovaries, as well as bleeding, stress, delayed embryo development, and smaller larvae.”
What’s more, excessive noise makes it much harder for large, intelligent marine mammals — whales, dolphins, porpoises — to sleep.
“There is no doubt that noise disrupts sleep in two ways,” said Jasny. “One is through acute effects — a resting whale hears some disruptive sound and high-tails it out of there. The other is through chronic stress.” He noted a recent study into the stress levels of North Atlantic right whales. They found one period in which the whales were abnormally relaxed: the months following September 11, 2001, when the eastern seaboard was relatively free of shipping traffic.
What’s bad for the sea is seldom very good for surface dwellers. Though the air-gun’s effects on human sleep are pretty much limited to sailors napping belowdecks, noise pollution can have a pernicious effect on maritime communities. The NRDC notes that air-guns decimate fish populations, reducing species like cod and haddock “by 40 to 80 percent.” These reductions directly impact fishermen and fishing communities around the world.
For example, in 1992, decades of overfishing caused the collapse of the Atlantic northwest cod fishery, reducing that region’s cod biomass to one percent of its previous level. The Canadian federal government issued a moratorium on cod fishing that disproportionately affected Newfoundland, a province more or less dependent on that industry. As a result, more than 35,000 fishermen and processing plant laborers were out of work. The government issued a relief package of several billion dollars to hundreds of coastal towns.
Today, fishermen affected by seismic surveys are seeking reimbursements directly from the oil and gas industry, according to the NRDC.
The regulatory framework governing seismic surveys is slim and fragmented, and doesn’t consider the long-term effects on global fisheries. As one of the authors of the Frontiers study told Nature, “The requirements vary from region to region. In many places around the world, surveyors must slowly ramp up the air-gun strength at the beginning of a survey, to warn off animals in the area, but we really don’t know how effective this practice is.” As Newsweek noted, survey protocol requires that “two government-certified third-party contractors constantly scan the area with binoculars. If something wanders into the area, they stop the work until the animal leaves.”
This strategy not only ignores the sheer vastness of the affected space — again, 100,000 square nautical miles — some animals don’t react to the noise as expected. Newsweek notes that right whales naturally swim toward boat-related sounds; with fewer than 500 of the species remaining, perhaps we shouldn’t leave their fate in the hands of two third-party contractors with binoculars.
Study authors call for a few sensible regulations: data-based restrictions of surveys in biologically sensitive areas, limits on the overall noise produced, wider adoption of lower-energy instruments and international coordination of efforts. Of course, they note, the global conversation has not yet started in earnest. Given the clout of the oil and gas industries, any serious regulation is surely years away.