By: Joe Gasper. What is Sonar? Sonar is originally a acronym for sound navigation and ranging Sonar...
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Transcript of By: Joe Gasper. What is Sonar? Sonar is originally a acronym for sound navigation and ranging Sonar...
By: Joe Gasper
What is Sonar?Sonar is originally a acronym for sound navigation and ranging
Sonar is used to detect other sea vessels, and to communicate between those vessels
Also sonar is used for navigation
Two Types of Sonar
Active SonarWhen sounds are
emitted in pulses, and listing for echo's
Passive SonarBasically used for
detecting noise made by other vessels
Active Sonar Active sonar can detect vessels that are to quiet to be picked up by passive sonar
Active sonar is also used to detect marine mammals such as whales
Also active sonar detects marine mammals in shipping lanes, or in high sound pressure zones.
These high sound pressure zones are usually used for military exercise
Passive SonarPassive sonar picks up sounds using electronic listening equipment.
A target can be detected by the noise it makes from its machinery, the propeller, or the sound of the water passing around the vessel as it travels.
What Type Causes More Harm?
The active sonar is what causes the problems for the whales
It is usually beaked whales beachedBeaked whales are mainly affected by the
active sonar
Difference in HertzMany military’s are now focusing on new
types of sonar
Military’s are testing and finding that low frequency sonar are not affecting, or stranding the beaked whales
This may led to a compromise between the military and environmentalists trying to protect the whales
Hertz Measurements
Low frequency sonar is different from mid frequency sonar
Low frequency sonar puts out between 100 and 300 hertz, whereas mid frequency sonar puts out between 2,000 and 10,000 hertz
How Military Sonar Affects WhalesWhy are whales beaching themselves
from the sonar?Researchers believe that the sonar causes
decomposition sickness or “bends”This is common among scuba divers that
rise to the surface to quick
Research Behind the StrandingIn 2002 there were autopsies preformed on
stranded beaked whalesFour hours after a military sonar test started
the beaked whales started to beach themselves
What Did the Autopsies Reveal?The researchers had eight beached specimen
to examineWhen they were performing the autopsies
they found two problems
Gas Bubbles in Blood Vessels
Hemorrhaged Vital Organs
Referenceshttp://www.biology-blog.com
http://www.whaleresearch.org
http://onemoregeneration.org
http://www.surtass-lfa-eis.com
http://misclab.umeoce.maine.edu
http://www.cascadiaresearch.org
http://medinfo.psu.ac.th/pr/MedBoard/Img/20100216110043.jpg
http://news.nationalgeographic.com/news/2004/03/0331_040331_whalesincrisis.html
http://news.nationalgeographic.com/news/2003/10/1008_031008_whalebends.html