Opposition grows to seismic testing for offshore oil amid concerns about impacts on marine life

Opposition grows to seismic testing for offshore oil amid concerns about impacts on marine life

A towed airgun array. (Ocean Conservation Research)

By William H. Funk 

Bay Journal

Scientists are worried that an executive order issued by President Trump earlier this year that seeks to open large portions of the mid-Atlantic and other coastal areas to oil and gas exploration would harm the endangered North Atlantic right whale and other species that occasionally visit the Chesapeake Bay.

Trump’s order, issued April 28, reverses a 2016 policy from the Obama administration that closed federal waters off portions of the Atlantic, Arctic and Pacific coasts and the Gulf of Mexico to drilling as part of the administration’s effort to boost domestic energy production. The order also instructed federal agencies to streamline the permitting process to speed approval of seismic testing to locate oil and gas reserves in those areas.

But the action is increasingly unpopular with many elected officials along the East Coast.

Hogan, Frosh opposed

In July, Maryland Gov. Larry Hogan publically stated his opposition to any further offshore exploration. And the attorneys general from nine East Coast jurisdictions — including those from Maryland, Pennsylvania, the District of Columbia and Delaware — submitted comments opposing additional surveys.

“The proposed seismic tests are themselves disruptive and harmful,” Maryland Attorney General Brian Frosh said in a statement. “Worse, they are the precursors to offshore drilling that would put the Chesapeake Bay at risk to drilling-related contamination. That contamination would have catastrophic impacts on fragile ecosystems and important economies. This is a foolish gamble with our precious natural resources.”

Gov. Terry McAuliffe of Virginia is the lone Southeastern governor supporting marine oil exploration, saying he “never had a problem” with seismic testing. While 127 municipalities have passed resolutions against the tests, only five are in Virginia.

But coastal Virginians’ unease with seismic tests appears to be growing. In July, the city council of Norfolk passed a unanimous resolution opposing both offshore drilling and seismic testing, citing threats to marine life, local fisheries and wetlands that offer vital protection from rising seas. The previous month, the city council of Virginia Beach also voted to oppose offshore drilling.

24/7 airguns

The seismic testing has raised particular concern because of its potential impact on marine life. The tests are conducted by firing seismic airguns from ships “every 10 seconds, 24 hours a day and seven days a week, at a noise level that would rupture a human eardrum,” according to the Center for Biological Diversity, an environmental group which was among 10 organizations that filed suit May 3 over the executive order. Among the plaintiffs’ contentions is that seismic blasts “could deafen and even kill whales, dolphins and other animals.”

Cetaceans — whales and their relatives — use specialized echolocation for almost all of their activities, including hunting, migration, courtship and communication, but they are extremely sensitive to underwater sound vibrations, scientists say. Right whales, whose population is thought to number only around 500, could be at particular risk, they say.

“As far as the impact goes, the chances of an animal being outright killed by seismic air gun arrays are slim,” said Doug Nowacek, with the Duke Marine Lab, according to Coastal Review Online. “The effects that we worry about mostly are producing sound in their environment, and that’s the sensory mode they use.”

To locate new sources of undersea oil, companies employ airguns to blast powerful acoustic waves formed of compressed air down and through the seafloor. Each seismic test can affect an area of more than 2,500 square nautical miles, raising background noise levels to 260 decibels, approximately equaling the epicenter of a grenade blast.

This can go on continuously for weeks or even months, according to a 2013 report released by the international body carrying out the United Nations-sponsored Convention on Biodiversity.

Not just whales affected, plankton too

Scientists say potential harm is not limited to large marine mammals. Zooplankton, tiny microscopic invertebrates that constitute the core of the marine food chain for everything from shrimp to baleen whales, could also be impacted.

In a June 2017 study published in the journal Nature, a team of marine ecologists found that, “experimental airgun signal exposure decreased zooplankton abundance when compared with controls, as measured by sonar and net tows, and caused a two–to threefold increase in dead adult and larval zooplankton.”

The study’s conclusion says that, “There is a significant and unacknowledged potential for ocean ecosystem function and productivity to be negatively impacted by present seismic technology.”

In May, 133 environmental and civic organizations sent a joint letter to Interior Secretary Ryan Zinke asking him not to proceed with the Trump administration’s plan to expand offshore oil drilling and related seismic testing, stating that “offshore drilling brings unacceptable risks to our oceans, coastal residents, communities, existing economies, and our climate.”

But Zinke followed up on the president’s executive order with an order of his own on May 11, setting the seismic testing in motion. “Seismic surveying helps a variety of federal and state partners better understand our nation’s offshore areas, including locating offshore hazards, siting of wind turbines, as well as offshore energy development,” Zinke said in a statement. “Allowing this scientific pursuit enables us to safely identify and evaluate resources that belong to the American people.”

The National Marine Fisheries Service has also proposed authorizing more than 90,000 miles of active seismic blasting which, based on the results of the Nature report, would constitute “approximately 135,000 square miles,” according to the Natural Resource Defense Council.

How it works

Reflection seismology, as the geophysical exploratory process is called, uses concussive compressed air to send a sudden shock of sound beneath the ocean surface. Oil deposits can be detected by a geological interpretation of what the bounced sounds, called reflections, reveal what lies beneath.

Reflections are gathered and collated by floating hydrophones, also called towed arrays or streamers, which emit 10– to 15-hertz echoes that bounce off the seafloor. Where geologically suitable, up to 20 or 30 kilometers of the ocean’s floor can be penetrated through this technique.

Oil companies look for two seafloor features to indicate the presence of oil: salt domes and seeps. Salt domes were created over eons when oceanic regions were repeatedly drowned and parched, to atmospheric events such as glaciation. This periodic give and take of oceanic deposits squeezes buoyant sea salt to the top of the sedimentary layer, trapping oil and gas underneath, which leaves a unique shape and composition detectable to seismic exploration.

Seeps occur when oil and gas escape from the seabed and cloudily rise through the water column toward the ocean surface, making them verifiable through onsite seafloor analysis.

Deafening array of underwater sounds

Maria Morell is with the zoology department of the University of British Columbia, and specializes in marine mammal acoustics. “When a mammal is exposed to an audible sound of high intensity and long duration,” she said, “the sensory cells of the inner ear can suffer mechanical and metabolical fatigue,” followed by “a cascade of alterations” that can lead to temporary or permanent hearing loss.

Testing for oil, she said, adds another stressful seismic factor to a deafening environment that the Atlantic’s marine mammals must confront every day, including “maritime transport, offshore oil and gas exploration and exploitation, industrial and military sonar, military and civilian engineering activities, supersonic aircraft noise, the construction and operation of sea-based wind farms, and acoustic deterrent and harassment devices.”

Ingrid Biedron, a marine biologist with the conservation group Oceana, said that Trump’s call for offshore drilling may be difficult to enact under federal law. “Current proposals conflict with the Marine Mammal Protection Act,” she said. “They also conflict with the Endangered Species Act because several endangered whale species use the area proposed for seismic airgun blasting.”

Citing a federal study, she said that, “If seismic airgun surveys are approved in the Atlantic, by the government’s own numbers, up to 138,000 whales and dolphins could be harmed and up to 13 million disturbed.”

Potential harm to marine species from seismic testing isn’t limited to cetaceans. Jessica Coakley, a fishery management specialist with the Mid-Atlantic Fishery Management Council, said that these impacts stretch from the recent stranding of giant squid off Spain in areas adjacent to seismic testing to sensitive habitats such as deep-sea corals.

Ocean noise roadmap

The recent National Oceanic and Atmospheric Administration’s Ocean Noise Roadmap recognizes that “sound is a fundamental component of the physical and biological habitat that many aquatic animals and ecosystems have evolved to rely on over millions of years.”

In addition, Coakley said, the University of Rhode Island, in partnership with NOAA, has created a website called “sound in the sea,” through which visitors can click to hear what seismic airguns actually sound like when heard several thousand kilometers away underwater.

The speed of sound underwater is five times faster than sounds traveling through air, so marine creatures perceive sound coming from much farther distances than their terrestrial counterparts.

For animals that rely on sound as much as we do on sight, it’s not difficult to imagine the grinding anxiety of being subjected to a constant bombardment of sensory deprivation caused by seismic activities, including oil exploration. Marine mammals already facing an uphill struggle for survival could face yet another industrial challenge.

“Scientists are especially worried about the North Atlantic right whale,” Beidron said, “Increased noise from seismic blasting could be one of the factors that further tips this species toward extinction.”

Last spring, 28 top marine mammal scientists specializing in right whales signed a statement declaring unequivocally that for this species, “among the most endangered whales on the planet,” and already facing a “desperate level of endangerment,” widespread seismic surveys may well represent a tipping point, “contributing significantly to a decline towards extinction.”


Bay Journal is published by Bay Journal Media, a 501(c)(3) nonprofit, to inform the public about issues that affect the Chesapeake Bay. A print edition is published monthly and is distributed free of charge. News, features and commentary are available free online at bayjournal.comMarylandReporter.com is partnering with the Bay Journal by publishing one of its articles every Friday.

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