The Atlantic Ocean is staring down the barrel of an air gun, and its blast could reverberate into the Chesapeake Bay.Surveying vessels tow air guns in their wake, generating blasts whose waves burrow deep beneath the ocean floor and bounce back to the surface. Recording equipment uses those waves to create 3-D maps of potential oil and gas deposits.

Despite outcry from coastal communities and most East Coast states, the Trump administration is moving forward with allowing five companies to perform seismic surveys offshore from Delaware Bay to central Florida.

Environmental groups and many marine scientists fear that the tests’ loud, repeated blasts, which are used to detect oil and gas deposits deep beneath the ocean floor, could upend an underwater ecosystem that relies on sound for communication.

“The ocean is an acoustic world,” said Michael Jasny, director of the Natural Resources Defense Council’s marine mammal protection program. “Whales, fish and many other species depend on sound to survive. The extensive blasting that the Trump administration has authorized
would undermine marine life on an enormous scale.”

The NRDC joined several environmental groups in a federal lawsuit filed in South Carolina in December, challenging the administration’s approval of the seismic surveys a month earlier. On Feb. 20, the conservation groups asked the judge in the case to block the seismic tests from going forward while the litigation is pending. The National Marine Fisheries Service decision allows the companies to “incidentally harass” marine mammals during the tests.

Although the surveys would take place along the outer continental shelf in the Atlantic, life in the Chesapeake wouldn’t be immune to the effects, experts say. Many species spend time in both the ocean and the Bay, including blue crabs, rockfish, whales and dolphins.

“The Bay is not isolated,” said Helen Bailey, a dolphin researcher with the University of Maryland Center for Environmental Science. “It connects to the Atlantic Ocean.”

The controversy highlights a stark divide between longstanding federal policy and many in the scientific community over the impacts of seismic technology.

Here’s how the tests work: A ship crisscrosses the ocean in a grid pattern, often trailing 18-48 seismic air guns. The guns release compressed air, triggering pulses of sound that penetrate deep into the ocean floor and echo back to the ship’s sensors, creating a 3-D map of what lies below.

The underwater booms are loud — up to about 250 decibels — and are the equivalent on land of a rocket launch. And the noise isn’t fleeting. The blasts can go off every 10 seconds and continue for months at a time, with only short breaks for maintenance and weather disruptions.

Scientists say that cacophony could disrupt the behavior of whales and dolphins, which depend on specialized sounds and echolocation for hunting, migrating and communicating. The endangered right whale, whose population has sunk to about 500 individuals, could be especially at risk.

For animals near a blast, consequences could range from them simply fleeing the area to suffering permanent hearing damage, Bailey said.

“An explosion is really a great way to describe it,” she said. “If you’re at home and there are explosions outside, even if it’s not loud enough to damage your hearing, it can be loud enough to annoy you.”

Nine state attorneys general quickly moved to throw their legal weight behind the environmental groups’ lawsuit aimed at stopping the surveys before they start. The intervening states include four in the Bay watershed: Delaware, Maryland, New York and Virginia.

The suit argues that the National Marine Fisheries Service violated several laws, including the Endangered Species Act, when it issued the permits.

Maryland Attorney General Brian Frosh said he decided to intervene because the tests could lead to drilling off the state’s coast, which he sees as a potential disaster-in-waiting for its $116 million seafood industry and $2.6 billion ocean-based tourism industry.

“Most of the water in the Bay comes from the ocean. It doesn’t flush quickly. Even the normal kinds of spillage that is attendant to offshore drilling could have serious adverse consequences for the Bay,” he said.

The groups siding with the NRDC include the Southern Environmental Law Center, Center for Biological Diversity, Coastal Conservation League, Sierra Club, Surfrider Foundation, Earthjustice and Oceana.

The biological opinion issued by the National Marine Fisheries Service estimates that the seismic surveys will not cause any deaths among whales. But the activity is expected to lead to the “harassment” of nearly 10,000 whales, including 19 right whales, and the “harm” of a dozen fin whales, according to the service.

But none of that harassment or harm, according to the agency, is predicted to rise to the level of jeopardizing the continued existence or recovery of any species. That’s a key distinction because a “jeopardy opinion” can lead regulators to quash a permit.

The Trump administration’s decision echoes years of federal policy toward seismic surveying. In 2014, the Bureau of Ocean Energy Management, which regulates the industry, published a carefully worded “science note” suggesting there has been “no documented scientific evidence” of sounds from air guns “adversely affecting marine animal populations.”

Although no seismic blasts have been permitted in the Atlantic for oil and gas exploration since the 1980s, it has been commonplace in the Gulf of Mexico and elsewhere for decades.

“If you look at the Gulf of Mexico, it is teeming with marine life,” said Gail Adams, a spokeswoman for the International Association of Geophysical Contractors, the trade association for the companies that perform seismic surveys. “We have some of the best seafood in the world, particularly off the coast of Louisiana. There’s just no evidence that sounds from our operations are harming or injuring marine life.”

Some scientists say that the lack of evidence for widespread, adverse impacts doesn’t mean they don’t exist.

“Just because there hasn’t been enough support for research to understand the effects doesn’t mean there are no effects,” said Alexander Costidis, a stranding response coordinator for the Virginia Aquarium and Marine Science Center. “I would argue there’s a decent amount of evidence to the contrary.”

Tracking the behavior of fish and marine mammals, though, is difficult because they ply depths not easily accessed by humans, he added. If a pod of dolphins ended up becoming stranded on a beach near a seismic surveying operation, for example, it would be nearly impossible to say with certainty that the two events were connected.

The survey proposal faces a growing chorus of political opposition. More than 200 cities and counties so far have taken formal actions to register their disapproval of oil and gas exploration along the East Coast, according to a database compiled by Oceana.

Under that pressure in late 2016, the Obama administration denied requests to restart Atlantic surveying and went a step further, indefinitely banning oil and gas exploration in certain offshore areas. The Trump administration’s go-ahead to the five companies late last year effectively reverses that policy.

“It’s like the zombie issue,” said Jay Ford, the Chesapeake Bay Foundation’s outreach coordinator in Virginia. “How many times can we tell you we don’t want you drilling off our coast — and you keep coming back?”