The Negative Effects of SONAR
The world was first introduced to SONAR during World War II. It was originally created by the Navy, for military use. It has since been used for a number of other things. Many people argue the need for the use of his device because of its powerful effects. Even though sonar can be used for positive medicinal purposes and research applications, SONAR technology can have harmful effects on marine life, humans, and unborn children.
To begin, SONAR has been used throughout history for several different applications. The uses of SOONAR began with the Navy. The Navy believed that SONAR was the only efficient way to track hidden enemy submarines [Alexander]. The Navy has also used SONAR to teach inexperienced sailors how to detect problems in their surroundings. Other uses of SONAR besides military uses now include commercial and scientific uses.
The word SONAR was invented by F.V. Ted Hunt who was the director of the Harvard Underwood Sound Laboratory. The word SONAR was developed from the words “sound navigation and ranging” [ScienceMag]. There are two major types of SONAR, passive and active. Passive sonar acquires sound waves reflected by another source, but it does not give off any noise. Passive SONAR has proved not to be as reliable as active sonar. The other type of SONAR is active SONAR. Active SONAR uses an apparatus called a transmitter which changes electrical energy to sound energy to transmit sound waves. These sound waves create anthropogenic noises, which imitate the sounds of marine mammals [Mora]. These sound waves go through the water until they hit an object. The sound waves then return to the receiver
on the sonar computer. After the computer receives the waves, it changes them back into electrical signals, which then produce a picture. Active SONAR is able to penetrate water and create images of what would otherwise be considered invisible because of its extreme depths.
Another word for active SONAR is echo ranging. Echo ranging is defined as the method of distance finding. SONAR figures distance by determining how long it takes for a sound wave to bounce off an object and report back to the receiver. The picture that is received by the receiver is made up of dark and light areas. Soft things such as sand and mud have weaker return signals, which in turn produce a lighter picture. It is the harder objects that reflect darker pictures, thus creating a detailed image of dark and light areas [Ocean Explorer]. Once a SONAR signal has been set off, it has a carrying distance of about ten nautical miles, which is equivalent to around eighteen and one half kilometers.
Reginald A. Fessenden demonstrated the power of echo ranging when he built a 540-Hz electronamically driven circular plate while he was working for the Submarine Signal Company in Boston. His electronic pre-sonar device detected an iceberg nearly three and a half kilometers off the coast of Newfoundland, Canada [D’Amico]. By 1933, the U.S Naval Research Laboratory installed echo ranging devices on eight destroyers. Soon people began to categorize the word SONAR with submarines and other underwater objects [The World Book Encyclopedia]. That was just the beginning of the development of a revolutionary detection device. Both echo ranging devices and SONAR are used today in oceans all over the world. Controversy has arisen over the possibility of its harmful effects. Although revolutionary scientific breakthroughs have
occurred with the advancements in technology such as SONAR and echo ranging devices, there have been recorded negative effects on animal marine life. A large percentage of sea mammals are acoustic animals. This means they use echo location for main purposes such as food, mating, and navigating their way around [Marine Connection]. Peter Tyack and some of his colleagues set up a study to investigate the uses of sound in these animals. Their study consisted of listening to the clicks of...
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