Underwater surveys, and the subsequent building and operation of offshore energy facilities, would create an earful for marine mammals. But some wonder: Is the cacophony safe — and is it worth the potential cost to habitats?
By Laura Dattaro
From the July 2015 issue
The waters off the East Coast today, much like the land itself two centuries ago, are poised for industrialization. In January, the U.S. Department of the Interior proposed opening up areas from Virginia to Georgia for new oil and gas production, a move that could affect ecosystems and economies up and down the Eastern Seaboard. At the same time, the Obama administration is pushing for offshore wind farms from Maine to Georgia, with areas off Delaware, Rhode Island, Massachusetts, Maryland, and Virginia already leased to wind companies.
With all of that development comes many environmental risks, including one that’s easy for humans to miss: sound. As on land, construction underwater is a noisy process, and that noise can present problems for the marine mammals, fish, and turtles that use sound to navigate through their watery world.
In order to find areas suitable for drilling, energy companies use a technique known as seismic surveying, which involves ships trailing air guns behind them that shoot sound wave blasts capable of penetrating the seafloor. That din, along with the eventual noise of the drilling rigs and vessels transporting the oil and gas, can pose risks for marine ecosystems and the coastal communities that depend on them.
But industrializing the East Coast could be a potential boon for domestic energy production. Recent estimates cite 4.7 billion barrels of oil waiting to be recovered from the Atlantic continental shelf, with about half of that in the mid-Atlantic section. That means weighing the benefits of new energy against the potential dangers of extracting it.
It’s enough of a concern for Delawareans that last July, while the administration considered the future of U.S. oil drilling, U.S. Rep. John Carney sent a letter to President Obama opposing the use of seismic surveys in the Atlantic. The Democratic congressman noted that such surveys could threaten the $16 million generated by commercial fisheries in Delaware, as well as the $600 million ocean-based tourism industry here. “Why are we heading off in this direction that poses such an incredible economic risk to our state and to the environment of southern Delaware?” Carney says about the proposal. “It just doesn’t make sense. It’s not worth the risk.”
What lies beneath
The ocean is a world of sound, and the waters off Delaware’s coast are packed with animals that rely on it. There are 36 species of marine mammals and sea turtles that live in or frequent Delaware waters, according to Suzanne Thurman, executive director of the Marine Education, Research, and Rehabilitation Institute in Lewes. Among them is the highly endangered North Atlantic right whale, which follows a migration route that hugs the coast from the Northeast to Georgia and Florida. Fewer than 400 remain in the world, and in the fall, some are usually spotted in the Indian River Inlet, sometimes spending time in and around Delaware Bay on their way to warmer waters. Little improvement has been seen in their numbers in recent decades, and the National Oceanic and
Atmospheric Administration identifies industrial noise as one of the threats to the species’ survival.
Right whales, like humpbacks, fin whales, and numerous dolphin species that swim and feed in Delaware waters throughout the year, use their own complex sounds for echolocation (a sort of marine animal “sonar”) while listening in on other creatures and noises in their environment. “These animals rely on underwater sound to communicate with each other, to navigate, to find food, to breed, to do everything that they do,” Thurman explains.
It is into this environment that humans are proposing to create an underwater cacophony in the quest to create new energy sources. While there isn’t much data on how such sounds can affect ecosystems in the Atlantic — no seismic surveys have been done here since the 1980s — there’s growing evidence from around the world that loud sounds can interrupt feeding behaviors, separate mothers from their calves, and cause temporary or permanent hearing loss and other injuries, some of which are fatal.
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