By Jim Robbins, The New York Times, January 22, 2019
A container ship crossing under the Lions Gate
Bridge in Vancouver. Increasing traffic and the threat of seismic blasts for
offshore drilling exploration are dangerous to marine life, scientists warn.CreditCreditAlana Paterson for The New York
Times
Slow-moving, hulking ships crisscross miles
of ocean in a lawn mower pattern, wielding an array of 12 to 48 air guns
blasting pressurized air repeatedly into the depths of the ocean.
The sound waves hit the sea floor,
penetrating miles into it, and bounce back to the surface, where they are
picked up by hydrophones. The acoustic patterns form a three-dimensional map of
where oil and gas most likely lie.
The seismic air guns probably produce the
loudest noise that humans use regularly underwater, and it is about to become
far louder in the Atlantic. As part of the Trump administration’s plans to allow offshore drilling for
gas and oil exploration, five companies have been given permits to carry out
seismic mapping with the air guns all along the Eastern Seaboard, from Central
Florida to the Northeast, for the first time in three decades. The surveys
haven’t started yet in the Atlantic, but now that the ban on offshore drilling
has been lifted, companies can be granted access to explore regions along
the Gulf of Mexico and the Pacific.
And air guns are now the most common
method companies use to map the ocean floor.
“They fire approximately every 10 seconds
around the clock for months at a time,” said Douglas Nowacek, a professor of
marine conservation technology at Duke University. "They have been detected
4,000 kilometers away. These are huge, huge impacts.”
The prospect of incessant underwater sonic
tests is the latest example cited by environmentalists and others of the
growing problem of ocean noise, spawning lawsuits against some industries and
governments as well as spurring more research into the potential dangers for
marine life.
Some scientists say the noises from air
guns, ship sonar and general tanker traffic can cause the gradual or even
outright death of sea creatures, from the giants to the tiniest — whales,
dolphins, fish, squid, octopuses and even plankton. Other effects include
impairing animals’ hearing, brain hemorrhaging and the drowning out of
communication sounds important for survival, experts say.
So great is the growing din in the
world’s oceans that experts fear it is fundamentally disrupting the marine
ecosystem, diminishing populations of some species as the noise levels disturb
feeding, reproduction and social behavior.
A 2017 study, for example, found that a loud blast,
softer than the sound of a seismic air gun, killed nearly two-thirds of the
zooplankton in three-quarters of a mile on either side. Tiny organisms at the
bottom of the food chain, zooplankton provide a food source for everything from
great whales to shrimp. Krill, a tiny crustacean vital to whales and other
animals, were especially hard hit, according to one study.
“Researchers saw a complete absence of life
around the air gun,” said Michael Jasny, director of marine mammal protection
for the Natural Resources Defense Council, one of several environmental groups
suing the federal government in an effort to stop the seismic surveys.
Measuring the sounds of commerce
Each seismic shot from the air guns is
estimated to reach up to 260 underwater decibels, equal to about 200
decibels in the atmosphere. Container ships, another noisemaker on the seas,
make sounds up to 190 decibels — the equivalent of 130 decibels in the atmosphere.
(The launch of a space shuttle, by contrast, reaches about 160 decibels for
those nearby.)
Every 10 decibels is an order of magnitude.
An explosion of 200 decibels, then, is 10 times more intense than the sound of
a container ship. Because water is much denser than air, sound travels
underwater about four times faster and much farther than above the sea’s
surface.
“At any one time, there are 20, 30 or
40 seismic surveys going on around the world,” for oil and gas
exploration, as well as for geological research, Dr. Nowacek said.
All told in the first year of the newly
approved exploration, more than five million of these huge explosions would
occur all along the United States’ eastern coastline.
Christopher Clark, a senior researcher in
the bioacoustics program at the Cornell Lab of Ornithology, who has studied
whale communication for 40 years, described the noise as a “living
hell” for undersea life, which is exquisitely tuned to sound.
A coalition of environmental groups has
filed suit against the National Marine Fisheries Service, a division of
the National Oceanic and Atmospheric Administration, claiming the agency is
violating several federal laws protecting wildlife, including the Endangered Species
Act, by allowing the blasts. And governors from 10 states have protested the
offshore drilling decision and are seeking to join the legal action.
Harming or injuring marine
mammals is forbidden under the Marine Mammal Protection Act. In November, NOAA issued five authorizations
allowing seismic exploration companies to “incidentally, but
not intentionally, harass marine mammals.” Because of the government shutdown,
other government action to begin testing has been postponed until at least
March 1.
The companies involved in the exploration
disagree sharply with the claims of harm. “More than 50 years of extensive
surveying and scientific research indicate that the risk of direct physical
injury to marine mammals is extremely low,” Gail Adams-Jackson, vice president
of communications for the International Association of Geophysical Contractors,
said in a statement. She contended that the groups’ efforts are solely aimed at
stopping offshore exploration and development.
The companies and NOAA Fisheries said that
the effects on marine life could be kept to a minimum by careful monitoring and
mitigation, which would involve acoustic monitoring to detect mammal
vocalizations and shutting down exploration when sensitive species like the
endangered North Atlantic right whales are observed.
There are no more than 400 to 500 of the
migratory right whales, which can grow up to 60 feet long, and calve and nurse
their young from North Carolina to Florida. Right whales are already emaciated
and stressed by a warmer ocean — they live in the Gulf of Maine, which has
warmed considerably more than other bodies of water. Reproduction has been
drastically reduced. And the seismic noise can mask ship sounds, resulting in
collisions, another leading danger for the whales.
“We require strong protections for North
American right whales in areas where they are expected to be present, including
all designated habitat,” Benjamin Laws, a NOAA biologist said, defending the
issuance of the permits.
Carrying sound across the
ocean
Cavitation, the noise from the synchronous collapse of bubbles created
by a ship’s propeller, as well as the rumble of ship engines, poses an ever
bigger problem to marine life. And shipping noise could double by 2030.
Years of constant blasts could be extremely
harmful, others argue, and not just for right whales. Because of the
way sound reverberates in the ocean, the noise can be unrelenting.
“Prolonged chronic stress of any kind is
bad, because it shunts resources away from reproduction,” Dr. Nowacek said. “It
presses your adrenal glands to produce adrenaline and stress hormones, causes
weight loss and immunosuppression.”
In a landmark study, when
ship traffic greatly decreased after the events of Sept. 11, 2001, researchers
noted a significant drop in stress hormones in the feces of right whales in the
Bay of Fundy in Canada, the first evidence that ship noise can cause chronic
stress in whales.
Moreover, acoustic
communication is primary in the marine ecosystem, where visibility is so
limited. Many whale species are highly intelligent, social beings and
communicate in the clicks, moaning, singing and calling of their own languages.
Some whales, and orcas (the largest in the dolphin family despite their killer
whale designation), hunt prey through echolocation, a kind of natural sonar.
“Sound can travel enormous distances very
fast and whales have evolved to take advantage of that,” said Dr. Clark, who
has listened to whales near Ireland from coastal Virginia. “They can hear
storms a thousand miles away.”
Aside from the seismic noise, compounded
sounds from container ships to navy sonar are posing a problem for marine life.
As the number of ships moving around the world has increased
significantlyin recent years, cavitation, the noise from the synchronous
collapse of bubbles created by a ship’s propeller, as well as the rumble of
ship engines, poses a bigger and bigger problem. A recent study found that
shipping noise could double by 2030.
Noise masks whale expressions between
families, which can affect orientation, feeding, care of young, detection of
prey and even increase aggression. Already 80 percent of communications of some species of whales is masked by noise, according to models assessed
by a team of biologists.
“It’s ripping the communications system
apart,” Dr. Clark said. “And every aspect of their lives is dependent on sound,
including finding food.”
About 20,000 known species of fish are able
to hear, and some 800 species are known to make sounds of their own to hunt,
mate, navigate and communicate. One fish, the plainfish midshipman, for
example, sings to the females to mate and defends nests with barking sounds.
Other studies show that beaked whales are
extremely sensitive to noise, and in frantic efforts to escape seismic air guns
or navy sonar they have been forced to change their dive patterns to the
surface. Some have died from decompression sickness.
Loud noises can also
affect behavior and even ecosystems by altering where species go. In
2008 in Canada’s Baffin Bay, seismic testing is believed to have delayed the
southward migration of narwhals — the whales with the long spiral tusk — until
it was too late and they became trapped in sea ice. More than 1,000 died.
The blasting can take a particular toll on a part of the body in invertebrates called
the statocyst. In octopuses, squid, lobsters and other invertebrates, the
organ is responsible for orientation and balance. Damaged, it disorients the
creatures and makes them vulnerable to predators.
Still, while research has expanded in the
last decade, much is difficult to pinpoint and sometimes impossible to study.
“You can’t study a whale’s hearing,” said Lindy Weilgart, a researcher at
Dalhousie University in Nova Scotia and the author of an analysis of 115 studies,
released in 2018.
The exposure of mammals to such noise has
been likened to living in a permanent construction zone. “Sometimes listening
on the headphones gives you a headache within 10 minutes,” Molly Patterson, a
researcher who studies underwater sound, said in the 2016 documentary
“Sonic Sea.” “You have to take the headphones off, you have to turn the volume
down. The whales can’t turn the volume down.”
One way many have escaped the cacophony is
by heading to the Arctic. But as polar ice melts, and seismic exploration and
ship traffic there increase, it is no longer the refuge it once was.
Ocean noise can also have economic
repercussions: Research in Norway shows that commercial fishermen return to the
dock with 40 to 80 percent fewer fish when exploration is underway nearby.
Regulations on underwater noise are few and
far between and experts are searching for solutions. The United Nations
recently held a weeklong symposium on
noise pollution and marine life.
Voluntary efforts to turn down the volume
are having an effect: The Port of Vancouver started the ECHO
(Enhancing Cetacean Habitat and Observation) Program, asking mariners to reduce
noise by having ships slow down and fix cavitation on the propellers.
At the same time, though, if the Trans Mountain pipeline is built from the tar
sands of Alberta to a port near Vancouver, as planned, tanker traffic in the
Salish Sea is expected to increase by seven times. Marine biologists say that
would exacerbate the difficulties the region’s endangered orcas already face in
finding prey.
Scientists and environmentalists are urging
that more research be conducted, to learn much more about the effects of sound
and ship traffic on the creatures of the sea.
“The effects on marine mammals are felt
across an extraordinarily large scale,” Mr. Jasny, the marine mammal protection
director, said. “And loud noise has an effect on species across the food web.”
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