20,000 Decibels Under the Sea

Jacques Cousteau took us to the bottom of the ocean and back in his acclaimed 1953 book, Le Monde du Silence (The Silent World). His documentary film bearing the same title won an Oscar in 1957. Today, Cousteau might have chosen a different name for his works, perhaps 20,000 Decibels Under the Sea.

Cousteau’s undersea world is getting to be a noisy place. You may not have heard the sounds of supertankers, cargo ships, military testing, or oil drilling on your Songs of the Humpback Whales CD, but they’re out there in force. Environmentalists say the ever-increasing racket poses a serious threat to marine animals and that steps should be taken to protect them. At least one perpetrator of underwater noise, the U.S. Navy, is hearing the message loud and clear.

The Navy is drawing fire over its use of a new low-frequency active (LFA) sonar system, which their experts say is essential for detecting superquiet enemy submarines developed for the post-Cold War seascape. It works by generating blasts of sound at upwards of 230 decibels (a jet engine is about 120 decibels at the source) from massive transmitters that ships drag through the water; technicians then interpret the echoes. The Navy wants to use this technology in 80 percent of the world’s oceans.

Jacques Cousteau took us to the bottom of the ocean and back in his acclaimed 1953 book, Le Monde du Silence (The Silent World). His documentary film bearing the same title won an Oscar in 1957. Today, Cousteau might have chosen a different name for his works, perhaps 20,000 Decibels Under the Sea.

Cousteau’s undersea world is getting to be a noisy place. You may not have heard the sounds of supertankers, cargo ships, military testing, or oil drilling on your Songs of the Humpback Whales CD, but they’re out there in force. Environmentalists say the ever-increasing racket poses a serious threat to marine animals and that steps should be taken to protect them. At least one perpetrator of underwater noise, the U.S. Navy, is hearing the message loud and clear.

The Navy is drawing fire over its use of a new low-frequency active (LFA) sonar system, which their experts say is essential for detecting superquiet enemy submarines developed for the post-Cold War seascape. It works by generating blasts of sound at upwards of 230 decibels (a jet engine is about 120 decibels at the source) from massive transmitters that ships drag through the water; technicians then interpret the echoes. The Navy wants to use this technology in 80 percent of the world’s oceans.

The Navy’s conclusion, that these changes have “no lasting biological significance,” raised the ire of critics. “These experiments only tested immediate observable changes in behavior to an exposure level of around 150 decibels, a sound well below the 240 decibel level at which the technology will be deployed,” writes marine researcher Leigh Calvez in The Ecologist (June 2000).

Indeed, it’s what the report doesn’t say that opponents find so compelling. During the tests off Hawaii, notes Earth Island Journal, members of the Hawai’i Ocean Mammal Institute found two abandoned whale calves and a baby dolphin in the test area. “We have never heard of anyone observing an abandoned calf in our nine years of research off the Hawaiian Islands,” OMI’s Marsha Green told Earth Island Journal. “The sonar tests may cause disorientation so the mother and calf become separated and then cannot find each other.”

In May 1996, 12 Cuvier’s beaked whales beached themselves and died on the Kyparissiakos Gulf coastline in Greece. The whales, a breed that rarely gets beached, were healthy and young and had no external signs of injury or disease. Writing in the journal Nature, A. Frantzis of the Department of Biology at the University of Athens, Greece, noted that a NATO vessel was conducting low-frequency sonar tests in the gulf at the same time as the whale deaths.

“We know that LFAS was used in the Kyparissiakos Gulf. We also know that no other LFAS tests or mass strandings have occurred in the Greek Ionian Sea since 1981. Taking the past 16.5 years into account, the probability of a mass stranding occurring for other reasons during the period of the LFAS tests is less than 0.07 percent,” wrote Frantzis.

Most recently, in March 2000, 17 marine mammals of various species stranded at several locations in the Northern Bahamas islands; seven died, while others were pushed back into the sea. A report from the National Oceanic and Atmospheric Administration, a government agency, concludes that “injuries to the six beaked whale heads were all consistent with an intense acoustic or pressure event . . . in particular all had some hemorrhages in or around the ears.” The strandings occurred the same day five Navy ships were in the area using mid-frequency active sonar, which is far less powerful than their LFA sonar system.

“The lesson to be taken is be precautionary,” says Michael Jasny, a policy consultant for the Natural Resources Defense Council. “There are too many uncertainties and risks to deploy a system of such wide geographic reach.”

Nonetheless, the Navy is sticking to its guns and plans to move forward with deployment. Where’s Jacques Cousteau when you need him?

UTNE
UTNE
In-depth coverage of eye-opening issues that affect your life.