Is spreading sonar smart science or overkill?
July 2, 1999
Web posted at: 4:43 p.m. EDT (2043 GMT)
Last of a three-part series
By Stephanie Siegel
CNN Interactive Copy Editor
EDITOR'S NOTE: The following is Part III of a special report examining the concerns among scientists and environmentalists that acoustic "pollution" from underwater sonar projects could degrade the habitats of whales and other marine life.
Because the Navy plans to deploy low-frequency active sonar (LFAS) to detect submarines, it will publish a required Environmental Impact Statement soon in the Federal Register showing the results of experiments on the sonar's impact on whales. The public will have 45 to 60 days to comment.
Another sonar project held four meetings this week in Hawaii for public input. The Acoustic Thermometry of Ocean Climate (ATOC) project is asking to extend its two-year permit to operate
low-frequency sonar under the water off Kauai another five years.
Some scientists and environmentalists say results from both projects are insufficient to prove that sea animals will not be harmed.
Both the Navy sonar and the global climate project have military connections.
Send comments about ATOC to:
Office of Naval Research
c/o Kathleen Vigness
Marine Acoustics, Inc.
901 Stuart Street, Suite 708
Arlington, VA 22203
ATOC's funding came from the Defense Department's Advanced Research Projects Agency, said Dr. Peter Worcester of Scripps Institution of Oceanography, a principal ATOC investigator, because an initiative from then-Sen. Al Gore encouraged the military to use its equipment and knowledge to advance understanding of environmental change.
Cornell University's Dr. Christopher Clark was a principal investigator in both ATOC's and LFAS's mammal studies, and Marine Acoustics Inc. is preparing environmental impact statements for both ATOC and LFAS.
The military connections have led to speculation about ATOC's use in military detection or communication. Worcester insists the equipment is not at all similar to LFAS. Its only use is in basic science.
However, the Office of Naval Research is interested in using the ATOC source to understand long-range acoustic propagation, Worcester said. When ATOC's Kauai permit expires in October, ONR wants to extend it for the next five years.
The California ATOC experiment has ended, and the sound source is to be retrieved. But the Navy wants the sea-floor cable left in place so it can set up a geophysical observation project involving several universities.
In a letter proposing that the Navy take over the cable, Naval Postgraduate School Professor Steven R. Ramp notes that the ATOC Environmental Impact Statement said the cable "would have virtually no impact if left unrecovered" and said "recovery of these cables is a relatively major undertaking." The 1995 Environmental Impact Statement had also predicted that "removal of the ATOC equipment might be forestalled by the takeover of the system by another approved project or follow-on experimental program."
The Naval Postgraduate School has had several RAFOS, or SOFAR (Sound Fixing And Ranging), sound sources in the north Pacific, too. Oceanographers use them to study things like ocean currents and seismic activity.
Acoustic Thermometry of Ocean Climate, Low-Frequency Active Sonar and Sound Fixing and Ranging (RAFOS) equipment has been tested or installed at various points around the north Pacific off and on since at least 1995.
Four still in the California area operate for 80 seconds twice a day, every day, at 183 to 189 decibels around 250 hertz, a
low-frequency range that parallels LFAS.
LFAS has been tested at 215 decibels between 100 and 500 hertz, according to Navy project manager Joe Johnson. That's more than 50,000 times more intense than 120 decibels, the level whales have been known to avoid.
Since detecting subs at long distances is the purpose of LFAS, and since the louder and lower the sound, the farther it travels, skeptic Jay Murray of the Society for Ocean Acoustic Research expects the Navy eventually will blast as loud (one prototype was designed to generate 248 dB, according to the Moby Dick Society) and as low (Murray says he has recorded 38 Hz) as the equipment will go.
Others believe LFAS will operate at 235 decibels. A sound of 230 decibels produces a pressure wave 300,000 times more intense than a 120 decibel sound.
ATOC operates at 195 decibels between 60 and 90 hertz for 20 minutes every four hours, one day out of four.
Murray questions whether each low-frequency source collected its baseline data and control data (results when "sound was off") while the other source was operating.
For example, ATOC's definitions of normal whale behavior could be based on observations gathered during classified LFAS tests from 1994 and earlier (which could have been at a lower frequency closer to ATOC's).
LFAS was tested off California for brief periods every year from at least 1994 to 1998, in the Persian Gulf, off Hawaii in 1996, off Alaska and British Columbia, and perhaps back to the 1980s.
ATOC's California transmitter was deployed in late 1995 and Kauai's in 1997, so both were operating when the closest LFAS tests were done. A short-term transmission test was conducted during June-July 1996 off central California to compare 28 hertz and 84 hertz transmissions at ranges of 3,500 and 5,100 kilometers. The naval school's RAFOS sources were deployed beginning in 1993 and 1994.
Because of the proximity of such sounds over the years, Murray suspects, whales may have become accustomed to hearing digitized low-frequency pulses. They would have shown a greater behavior change if the sound was new, he said.
However, RAFOS and ATOC "have very different characteristics," said Dr. Dan Costa of the University of California at Santa Cruz, who studied ATOC.
Wildlife biologist Christine Gabriele, who worked on both ATOC and LFAS mammal observation teams, said a whale would not confuse ATOC with LFAS. ATOC produces a deep rumble, like a rolling bowling ball, while LFA produces a falling pitch -- like a whale.
The total level of sound -- from shipping, for example -- could have habituated whales to a noisy environment, Costa said, but that has not been studied.
Only two ships?
With satellites and enough low-frequency sources -- low enough, loud enough, continuous enough -- including the use of programs like ATOC thermometry or RAFOS or Dr. Ramp's oceanography, environmentalists fear a grid of near-continuous sound will be produced to map the world's oceans and everything in them.
"Science fiction," says Johnson. "These (Navy sonar systems) have extended range, but it's certainly not thousands of miles," he said.
(Courtesy U.S. Navy)
But low-frequency sounds, such as the blue whale's call, are believed to travel thousands of miles underwater if they enter one of the natural sound channels found several thousand feet under the surface.
Clark thinks blue whales use echolocation to chart a course across oceans. They holler, and an hour or so later their echo comes back from an island, seamount or oceanic ridge 600 miles away. They'll swim all week straight toward one island, and when finished feeding there, head straight off for another one days away.
A blue whale in the middle of the north Atlantic, if it sang long enough, could reconstruct the ocean's topography in its mind the way a hospital's sonography draws a picture of a fetus, Clark hypothesizes. It might have that big an acoustic memory; the acoustic section of its brain is 10 times larger than that of humans.
The Navy once asked some scientists, "If you had a sound source that sounded like a blue whale voice, what would you be able to do with it?" Clark said. The unanimous answer was that it "could illuminate an entire ocean basin."
ATOC's long-range plan originally called for 10 to 12 loudspeakers, covering all the world's oceans and lasting at least 10 years, said whale biologist Dr. Linda Weilgart of Dalhousie University.
But Worcester said there is currently no ATOC proposal or funding for more than Kauai. Oceanographers will meet this fall in France to begin discussing a global ocean observation system, but there's no global plan yet.
However, Worcester said former ATOC director Andrew Forbes is in Australia preparing what a 1998 news release called a "hydroacoustic network of sound transmitters and listening posts across the Indian Ocean" in the year 2000 to map temperatures "thousands of kilometers."
In October 1998 a 20 hertz acoustic source was deployed from a Russian icebreaker in the Arctic to transmit to a receiver 1,000 kilometers away, according to a paper presented at a February 1999 symposium. It was one of the first installations of an acoustic thermometry grid for the Arctic Ocean under the ACOUS program directed by Peter Mikhalevsky of Science Applications International Corp. The source is designed for a three-year life, and a second acoustic source is planned for installation in 2000/2001.
Researchers from the Japan Marine Science and Technology Center are proposing 20 hertz sources for monitoring global ocean variability over 10 years. A 200 hertz source has been developed for ocean acoustic tomography of 1,000-kilometer scale.
The U.S. Navy proposes only four ships with LFAS, and only two are currently planned, Johnson said.
New, smaller technologies are being investigated for potential applications in a compact LFAS system for use on existing ships, according to the Federation of American Scientists.
"We have a global Navy, and we're not going to restrict where the system will be deployed," Johnson said. "It could be worldwide."
Low-frequency systems "would, in their most advanced form, see multiple LF active sonar platforms dispersed in a large sea area," Joris Janssen Lok wrote in Jane's Defense Weekly in 1991.
The Navy's own map shows LFAS territory covering some 80 percent of the world's oceans. France, the United Kingdom, the Netherlands, NATO, Italy, Spain and other countries have been involved in discussions or development of active sonar.
The Marine Mammal Commission reported to Congress in 1998 that LFAS could affect all marine species worldwide. It could disrupt feeding, breeding, nursing or hearing, the commission wrote. It could cause psychological or physical stress, making animals more vulnerable to disease, parasites and predators. And it could kill off or change distribution patterns of their prey.
Yet when 12 whales stranded in the Mediterranean in 1996 during a NATO LFA exercise, their stomachs and bowels were studied, not their ears.
Dr. Bruce Mate of Oregon State University, who theorizes that starvation may have caused an unusual number of whales to strand off California and Baja this spring, says he doesn't know of any plans to look for a connection between whale strandings and sound.
Possible marine mammal responses to noise
(suggested by earlier studies)
Ear or lung damage
Temporary or permanent hearing loss
Disorientation/loss of direction
Violent, aggressive behavior
Movement away from migration path, feeding or breeding grounds
Inability to hear quieter sounds like predators or prey when loud sound is on
Death or disease of prey
Change in breath rate, swimming speed, direction, dive speed, dive depth
Stoppage of use of their own active sonar for hours or days
At least 65 gray whales washed up on the shores of Baja California by mid-May this year, the highest number in the 24 years that people have kept track, according to the Mexican Society for Marine Mammalogy.
It has been suggested that El Nino and low food stocks in the Bering Sea could be to blame for a delay in gray whales' autumn migration southward, a drop in their calving success, and the fact that they seemed to swim farther offshore.
An unusually high number of gray whales entered Puget Sound this spring, a researcher said, probably detouring to find something to eat on their way from Mexico to Alaska.
No formal survey was done of Hawaiian whales this season, said Dr. Joseph Mobley, who did aerial surveys there in 1993, 1995 and 1998.
Johnson said he has heard from people in Hawaii that this year's humpback whale season was perfectly normal, though a little late. That contradicts the observations of some whale-watching Hawaiians.
"Where I go in my boat from Kailua Pier to Kealakekua Bay, about 10 miles, I saw in the previous year six or eight mother-calf combinations in that distance," Capt. Michael Yee said. "This year there was only one mother-calf pair."
Whale-watching guides have been helping each other find whales to show to tourists, Yee said. "Every day on the radio, 'Have you seen anything?' In years past there was not that heavy cooperation between the different companies, because it was not necessary."
The whales changed their migration pattern and showed up near Kauai, he heard from acquaintances there. "They have more whales than they've ever had."
It is impossible to infer long-term effects by studying only effects over the short term, said Weilgart.
In fact, the ATOC Environmental Impact Statement says the mammal study "is not designed to detect subtle or long-term changes."
"I am personally going to recommend that we continue to study this," Johnson said, "because the big unknowns really are going to be in overall long-term cumulative effects (this could be generations), and that affects much more than LFA.
"When there's 100,000 good-size freighters and supertankers out there, manmade noise dominates the frequency spectrum from 20 hertz to 200 hertz," Johnson said. "You really have to start asking, 'How would one or two ships have an impact?' And the answer would be, you'd have to go to someplace so sensitive, it would be hard to do it if you tried."
Others in the Navy are studying total ambient noise, Johnson said. Ocean animals and plants also suffer from other kinds of pollution: dumped plastic, metal and biodegradable wastes; oil spills; pesticides and industrial chemicals washed to sea. They face global warming, which apparently is raising sea levels, eroding shores and killing corals and other delicate ingredients in the food chain.
It may be impossible to isolate a single cause for the shrinking populations of the sea.
Does the Navy need LFAS?
A U.S. district judge in Hawaii, dismissing environmentalists' request to stop LFAS testing last year, said the Navy needs to develop its future antisubmarine technology.
Not everyone agrees that there is such a need or that LFAS is the way to go. A contractor warned in a trade magazine article that active sonar would reveal its source, drawing enemy fire.
U.S. Sen. Russell D. Feingold, arguing in January in Congress against a different low-frequency Navy system, ELF, said no enemy submarines threaten the United States. "The submarine capabilities of our potential adversaries have noticeably deteriorated or remain far behind those of our Navy."
The Navy doesn't claim the United States is under threat of a sub attack. The EIS team LFAS Web site shows shipping channels around the world where submarines "could be used in the future to disrupt peace and stability by interrupting transportation and commerce, thus impacting the world economy."
Sonar and marine life
Sea life threatened by noise pollution, report says
June 28, 1999
Groups fight Navy's low-frequency sonar
April 16, 1998
Scientists, environmentalists clash over whale research
March 31, 1998
CNN TravelGuide Destinations: Nature exhibits - Sounds of the sea
Ocean-monitoring system proposed
May 18, 1999
Right whales in the wrong place
March 4, 1999
Scientists prepare for humpbacks' survival
February 26, 1999
Gray whales slow to start winter migration
December 22, 1998
Unsafe sanctuaries: Protection varies at America's marine reserves
November 25, 1998
Better stewardship urged for humpbacks
April 4, 1998
Researchers: Right whales unusually scarce off Southeast Coast
February 2, 1999
Acoustic Thermometry of Ocean Climate (ATOC)
Low-Frequency Active Environmental Impact Statement
Natural Resources Defense Council
Quiet Sea Coalition
Ocean Mammal Institute
Magical Island Sounds
Hawaiian Islands Humpback Whale National Marine Sanctuary
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