Seismic Air Guns for Oil Exploration: Impact on Marine Life

seismic air gunsOn Thursday, the Bureau of Ocean Energy Management released an Environmental Impact Survey, three years in preparation, assessing a proposed project to use seismic air guns for exploring the offshore oil and gas resources beneath the U.S. Atlantic outer continental shelf range, and proposing mitigation measures to diminish the impact on marine life.

The energy industry says potentially vast reserves lie in the depths of the Atlantic, but they claim these could be uncovered only by seismic surveys, performed by towing seismic air guns blasting extremely loud sounds down to the seabed to detect the size and location of hydrocarbon deposits.  Environmental groups say the use of this technology will have a devastating effect on marine wildlife, especially threatening to populations of right whales, with humpback whales, dolphins, and loggerhead turtles being impacted as well.

Obviously an issue like this is extremely contentious, with emotions running high on both sides of the question, pitting as it does, the vast financial reserves of the fossil fuel industry against animal rights activists and environmentalists.  People who are ambivalent about this technology may be wondering how to realistically get an answer from a whale about the damage caused by the seismic air guns.  Without knowing anything about oceanography, or cetacean behavior, the average newsreader is left to form an opinion on the basis of gut feelings.  Gut feelings, however, are not the most solid evidence on which to base policy.

So here are some questions that one might pose, in order to gain a better understanding.

First, exactly how loud are seismic air guns really? The air guns produce a sound measured at 190 dB.  For comparison, the sound of a motorcycle shredding the air down your block comes in at 100dB.  A jet engine lets off 140dB of noise.  It should be noted that loudness is measured on a logarithmic scale; each 10 dB increase is a ten-fold increase in power.  Thus, the air guns are a staggering one billion times louder than that irritating motorcycle.  Furthermore, because the sounds generated by the seismic air guns propagate through marine water, the sound is approximately 63 dB louder than a sound with the same intensity in air.  That means six more zeros need to be appended to that billion, turning it into an unimaginably loud quadrillion times louder than the motorcycle.  Now imagine that a noise that unpleasant is being repeated every 12 to 16 seconds, for up to 24 hours at a time, for weeks or months.  Who would be a whale?

Two, how does oceanic noise pollution affect marine life, and how large an area is affected?

Because a numerical analysis cannot quite convey the subjective experience of being anywhere near something that loud, one needs to turn to available published reports on how this technology will affect marine life.  According to the National Resource Defense Council, ongoing research indicates that noise pollution in the ocean negatively impacts at least 55 marine species, including several endangered whale species and 20 species of commercially valuable fish.  Whales and dolphins rely on their hearing to find food, communicate, and reproduce, thus being able to hear critically affects their survival.  The use of seismic air guns has been shown to affect animals in an area of more than 100,000 square nautical miles.  For an understanding of how huge this is, if 100,000 square nautical miles were centered over Washington DC, it would extend from the northern edge of New Jersey to the middle of North Carolina, covering two thirds of Pennsylvania, all of Maryland, and a large chunk of Virginia.

Exactly which species are threatened and in what way? Marine life is far too diverse and complex to make a realistic assessment of all the possible ramifications of the use of the air guns.  However, research from NOAA and Cornell, indicates that one of the most vulnerable is the critically endangered North Atlantic right whale – of which only 400-500 individuals survive –  whose calving grounds off Florida and Georgia would be directly impacted by the proposed survey.  Airguns have also been shown to affect a broad range of other marine mammal species including sperm whales, whose foraging appears to decline significantly on exposure to even moderate levels of airgun noise.  Harbor porpoises have been observed engaging in strong avoidance responses as far as fifty miles from a seismic array.  Seismic surveys have also been found at fault for long-term loss of marine mammal biodiversity off the coast of Brazil.  Seismic air guns kill larvae and fish eggs and cause declines of 40 to 80 percent in the catch rates of haddock and cod areas up to thousands of miles away. Beyond the environmental considerations and the effects on marine mammals, the decline in catch rates of commercial fish has a strongly negative economic impact; fishermen in some parts of the world have begun to seek industry compensation for their losses.

And finally, despite all the already available information on the impact of oceanic noise pollution, not all the facts are in yet.  The National Marine Fisheries Service (NMFS), a division of NOAA, is completing a 15-year research program gathering information on how marine mammals are disturbed and damaged by sound.  Last week, a group of more than 100 scientists wrote to Obama urging him not to finalize the Environmental Impact Study until the latest marine mammal acoustic guidance is available.

So, who is on the other side of this issue?  Well, the oil industry, primarily.  That, and a number of Southern governors, who say offshore drilling could bring new jobs to their states.  Nine companies have applied for permits to use the seismic air guns to determine how much fossil fuel lies beneath the water off the Atlantic coast from the mouth of Delaware Bay to just south of Cape Canaveral, Florida.

Worse yet, an estimate of the undiscovered oil and gas resources beneath the U.S. Atlantic outer continental shelf range already exists.  Government estimates put the possible stores at 1.3 to 5.58 billion barrels.  But energy industry officials want to undertake a new study using the seismic air guns, claiming that the last energy exploration of the offshore Atlantic which occurred in 1988, was performed with equipment that is now outdated.

According to Erik Milito, director of upstream and industry operations for the American Petroleum Institute (API), drilling in the Atlantic could add “1.3 million barrels equivalent per day to domestic energy production…”

BOEM Director Tommy Beaudreau indicated a commitment to balancing the need for information on offshore energy resources with the protection of the human and marine environment.    The EIS estimated “minor to negligible” impact to most wildlife, with a “moderate” impact on marine mammals and turtles. The review estimates approximately 138,000 marine animals could be injured, and the feeding, migratory, and other behavioral patterns of 13.6 million other marine animals would be disrupted by the seismic surveys.

In the final analysis, these surveys are undertaken for the purpose of perpetuating dangerous and dirty offshore drilling, incurring possible habitat destruction, oil spills and contribution to climate change and ocean acidification. Exploration of the BOEM website shows that this organization is very committed to clean and renewable energy production, such as the “Smart from the Start” program to speed development offshore wind energy development off the Atlantic Coast.  Other programs include development of wind, wave, current, and solar energy; and alternative uses for offshore oil and gas platforms such as research, education, recreation and offshore aquaculture.  All of which, going with a gut feeling, will probably be much cleaner, healthier, and ultimately more economically sound, than dragging out the protracted demise of the fossil fuel industry by insisting on the use of seismic air guns to perform noisy, environmentally dangerous, and possibly unnecessary surveys.

by Laura Prendergast

National Geographic

Bureau of Ocean Energy Management

Washington Post

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