|NSS Home Page Nature Sounds Newsletter Winter 1995 Is The Ocean Getting Noisier?|
Is The Ocean Getting Noisier? (ATOC) Project Set to Begin This Fall
by Kelly Allman
An environmentally unsound way to study the environment is scheduled to begin this October off the coast of Half Moon Bay at Pioneer Seamount. The Acoustic Thermometry of Ocean Climate, ATOC, a project to transmit loud low frequency sounds across the ocean, was recently approved by the National Marine Fisheries Service and the California Coastal Commission. The purpose of the project is to measure ocean climate by changes in the speed of the sound, and to measure the impact of sound on marine mammals. ATOC, is the brainchild of Dr. Walter Munk, an oceanographer at Scripps Institution of Oceanography, who is known for his Bikini Island experiments.
The nature of the ATOC sound (center frequency 75 hertz, 195 dB, 20 minutes duration) has potential masking effects that could interfere with communication signals used by marine mammals, and is likely to interfere with the behavior, vocal communication, and distribution of marine mammals. The effects on other marine species are difficult to predict. The initial plan is to emit the sound for twenty minutes an hour every hour for four days on, seven days off cycle for two to ten years. The amount of emission time will increase if the initial phase of the project finds there is no impact on marine mammals.
Speakers around the Pacific Rim (as far as New Zealand) will receive the ATOC sound. The sound can travel roughly 10,500 kilometers and will be detected above ambient ocean noise for at least 3,S00 kilometers. Ironically, the sound will travel through the SOFAR channel, which the large endangered whales have been known to use for communication.
A four-day feasibility study associated with ATOC (costing in the millions of dollars) concluded that there are changes in the behavior, distribution, and vocalizations of marine mammals due to loud, low frequency sounds. The vocalizations of Sperm and Pilot whales ceased during the transmission period. One Blue whale changed respiration and reorientation rates while the sound was on. Bowhead and Gray whales also exhibit avoidance behavior to sounds louder than 160 dB. The list goes on and on, clearly, this project poses potential risk to marine mammals which we are not equipped to counteract, beyond that we can detect with proposed methodology.
Another issue of concern is the fact that the feasibility study chose to ignore a group of 275 Pilot whales for the sake of statistical convenience. This type of statistical packaging concerns me when it comes to deciding what constitutes an 'impact' on the animals, a determination that will affect the duration of the project (two or ten years).
The authors of the feasibility study also admitted that the exact range of influence from a sound of this type is "impossible" to characterize, due to oceanographic features.
The difference between the ATOC sound and the usual noise pollution caused by tankers, and the like is that the ATOC sound is long, disharmonic, and does not provide 'relief, i.e. a break in intensity. A loud crashing sound from an oil tanker is perhaps a few seconds to a few minutes in duration. The ATOC structure could be a very damaging form of noise pollution. Ocean animals are already impacted by chemical pollution, vessel traffic, resource depletion and whaling. Why is this project proceeding? It has been funded by the Department of Defense, and there is a lot of money involved here (to the tune of 35 million tax dollars at least). Outside of the questionable methodology and political motivations, some scientists feel this is a feasable way to measure global warming and people want to work.
Another sad fact is there are many environmental groups, including the Sierra Club Legal Defense Fund, NRDC, Humane Society, Earth Island Institute, American Oceans Campaign, and the Environmental Defense Fund were initially opposed to this project, and then agreed to sign a signatory on the advice of their lawyers. Apparently in the interest of self preservation (so they would not lose in court) these groups decided that they would pass on this matter by signing the signatory. The general public is opposed to the project, and it is curious how these major environmental groups went against their constituents' wishes.
The worst part of this all is that we may not even be able to gauge immediate impacts on the animals from this sound. We do not know enough about the low frequency sounds and their impact on marine mammals because it is very difficult to measure an "impact" on large, moving aquatic animals. Even the most polished statistician can be a clueless observer with regard to what a genuinely 'significant' behavioral disturbance on these animals would be. The proposed area of study is only a 80 kilometer transect, a fraction of the distance covered by large whales in a day's travel. What will the impact be far beyond, where the researchers will not be doing surveys? Is the sound going to have "no impact" out there? Is the protocol for these areas out of sight, out of mind? What if one our endangered animals happen to use the SOFAR channel? We will not be able to tell the fate of these missed data points.
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