by colemanyoungerinalaska » Thu May 31, 2007 7:42 am
http://www.youtube.com/watch?v=eKPrGxB1Kzc
http://www.youtube.com/watch?v=ONQlTMUYCW4
The snapping shrimp competes with much larger animals, like the sperm whale and beluga whale, for the title of 'loudest animal in the sea'. The shrimp snaps a specialized claw shut to create a cavitation wave that generates acoustic pressures of up to 80 kPa at a distance of 4 cm from the claw. The pressure wave is strong enough to kill small fish [7]. It corresponds to a zero to peak pressure level of 218 decibels relative to one micropascal (dB re 1 μPa), equivalent to a zero to peak source level of 190 dB re 1 μPa at the standard reference distance of 1 m. Au and Banks measured peak to peak source levels between 185 and 190 dB re 1 μPa at 1 m, depending on the size of the claw.[8] Similar values are reported by Ferguson and Cleary. [9]. The duration of the click is less than 1 millisecond.
The snap can also produce sonoluminescence from a collapsing bubble, also known as a cavitation bubble. As it collapses, the cavitation bubble reaches the surface temperature of the Sun [10]. The light is of lower intensity than the light produced by typical sonoluminescence and is not visible to the naked eye. It is most likely a by-product of the shock wave with no biological significance. However, it is the first known instance of an animal producing light by this effect.
[url]http://www.youtube.com/watch?v=eKPrGxB1Kzc[/url]
[url]http://www.youtube.com/watch?v=ONQlTMUYCW4[/url]
The snapping shrimp competes with much larger animals, like the sperm whale and beluga whale, for the title of 'loudest animal in the sea'. The shrimp snaps a specialized claw shut to create a cavitation wave that generates acoustic pressures of up to 80 kPa at a distance of 4 cm from the claw. The pressure wave is strong enough to kill small fish [7]. It corresponds to a zero to peak pressure level of 218 decibels relative to one micropascal (dB re 1 μPa), equivalent to a zero to peak source level of 190 dB re 1 μPa at the standard reference distance of 1 m. Au and Banks measured peak to peak source levels between 185 and 190 dB re 1 μPa at 1 m, depending on the size of the claw.[8] Similar values are reported by Ferguson and Cleary. [9]. The duration of the click is less than 1 millisecond.
The snap can also produce sonoluminescence from a collapsing bubble, also known as a cavitation bubble. As it collapses, the cavitation bubble reaches the surface temperature of the Sun [10]. The light is of lower intensity than the light produced by typical sonoluminescence and is not visible to the naked eye. It is most likely a by-product of the shock wave with no biological significance. However, it is the first known instance of an animal producing light by this effect.