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very strong. Humans are changing the cli-mate, and we’re expected to change it a lot more in the future.” Sounding Off for Whales Though the objectives are laudable, deep-sea acoustical experiments are not neces-sarily harmless. For example, observing the aforementioned 1991 experiment in the In-dian Ocean, a researcher at Hubbs-Sea-World Research Institute, Ann Bowles, reported “unequivocal evidence of behav-ioral effects” on sperm, pilot, beaked, and minke whales.” The most dramatic effects, she said, were seen in sperm whales, whose clicks were frequently detected be-fore the experiment, but fell completely silent for 36 hours afterward. ATOC, too, was not without its detrac-tors. Concern stems from the fact that no one really knows how the cacophony of human-generated subsea noise affects any of the ocean’s creatures. As a 1994 special-ists panel convened by the National Re-search Council concluded, “At this time, essentially nothing is known about the au-ditory after effects of exposure to intense sound in marine mammals, fish, or inverte-brates.” As a result of public protests against ATOC, the project was delayed and signifi-cantly revised. The original location of the broadcast transmitter — within a marine mammal sanctuary — was changed. In ad-dition, the broadcasts were restricted to six times a day for up to four days, which was less frequently than planned. The sound pressure was reduced a hundred-fold from that of the early Indian Ocean experiment. The loudspeakers used to gen-erate sound were moved into deeper water (3,200 feet [970 m]), where it was thought few marine mammals range; and a different frequency of 75 hertz was chosen because it was thought to be used by fewer animals. Most importantly, before climate research could proceed, the Ma-rine Mammal Research Program was formed to measure the effects of ATOC’s low-frequency sounds on whales, dolphins, elephant seals, sea lions and sea turtles. Though as ambitious as it was, the ATOC project was dwarfed by a clandes-tine program begun by the U.S. Navy in-volving a technology known as Low-Frequency Active (LFA) Sonar. If suc-cessful, LFA sonar will be able to detect submarines by broadcasting low-frequency sounds that are 10,000 times more power-ful than the ATOC transmissions. The problem — for whales, that is — involves the power of the sound signals. Each loud-speaker in the LFA system’s array can gen-erate 215 dBs. That’s as intense as the sound produced by a twin-engine jet fighter at takeoff. And some midfrequency sonar systems can put out even more — more than 235 dbs. That’s equivalent to the launch of a Saturn V rocket. Even 100 miles (160 km) from the LFA system, sound lev-els can approach 160 dbs, which is well be-yond the Navy’s own safety limits for humans. Opposition to the project has been led largely by the non-profit Natural Resources Defense Council (NRDC), which revealed that the system had already been field-tested and plans were to deploy it in 80 per cent of the world’s oceans. Sadly, the concern over LFA sonar is not speculative. In March 2000, whales of four different species stranded on beaches in the Bahamas after a Navy bat-tle group used active sonar in the area. At necropsy the whales were found to have internal bleeding around their brains and ears. The NRDC said, “Although the Navy initially denied responsibility, the govern-ment’s investigation established with vir-tual certainty that the strandings were caused by its use of active sonar.” Further-more, since the incident the local popula-tion of Cuvier’s beaked whales has disappeared because they’ve either aban-doned the area or died at sea. Alarmingly, the Bahamas incident is not isolated. Additional strandings and deaths associated with military activities and LFA sonar have occurred in Madeira (2000), Greece (1996), the U.S. Virgin Islands (1998, 1999), the Canary Islands (1985, 1988, 1989, 2002, 2004), the northwest coast of the United States (2003) and coastal waters off North Carolina (2005). The creatures that live underwater are easy to see and appreciate, so it takes little imagination to understand how studying them can give us valuable insight into their world. But it’s just as important for us to understand the less obvious physical sci-ence of the sea. How light, sound and other forms of energy behave in the ocean can lead to insights never imagined, and provide a global perspective that we can never achieve by looking at individual or-ganisms or even entire ecosystems. Clearly, the “silent world” is a misnomer. Sound is as much a part of the sea as any of the creatures that live within it. Resources For more information on the effect of LFA sonar on whales and other marine animals, and what’s being done about it, check out the Natural Resource Defense Council’s website: “Discovery of Sound in the Sea” FLAMINGO DIVERS WEST CAICOS • FRENCH CAY • NORTHWEST POINT • SANDBORE CHANNEL Located on Venetian Road Tel/Fax 649 333-DIVE (3483) Email: • Web: • • • • • 95 “PROVO’S LITTLE DIVE SHOP” PRIVATE CHARTERS -SMALL GROUPS -8 Divers Max. Visit the Turks & Caicos Islands at NOV/DEC/JAN/FEB 2017/2018

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