Quote from: Koen1 on November 27, 2008, 02:53:13 PM
No, that is true, it is more in the league of the sonoluminescence experiments I mentioned.
Temperature-wise that is, because the mechanism does make use of physical displacement of the water
and that is not unlike prop cavitation.
But to give you some clearer links on the relationship between our sonoluminescence experiments
and the shrimps' cavitation "pistol action", I shall provide a link or two for your interest.
Now first of all the schwikipedia even has these factoids correct:
"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 cavitation bubble. As it collapses, the cavitation bubble reaches temperatures of over 5000 K.[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." (from http://en.wikipedia.org/wiki/Pistol_shrimp)
And here's a little link to some sonoluminescence info: http://www.nature.com/nature/journal/v434/n7029/full/nature03361.html (Oh, sorry, I see one may only
read that article when registered... perhaps someone can find another version of the article?)
Here's some more info on "single bubble sonoluminescence", as these cavitation experiments are called, and their relation to plasma:
Let's start simple: http://en.wikipedia.org/wiki/Sonoluminescence
http://cat.inist.fr/?aModele=afficheN&cpsidt=16572452
http://www.ncbi.nlm.nih.gov/pubmed/16090812
http://www.scs.uiuc.edu/suslick/pdf/nature.030205.pdf
http://lib.bioinfo.pl/pmid:15744295
http://www.iop.org/EJ/abstract/1402-4896/72/1/012
And here's what schwikipedia has to say about "bubble fusion", which is obviously related: http://en.wikipedia.org/wiki/Bubble_fusion

In any case, my point is basically that the Pistol Shrimp uses sonically induced cavitation which is exactly what they're doing in the
luminescence (should actually read: localised plasma generation inside cavitationally generated microbubbles) experiments. The shrimp
uses its claw to produce the abrupt pressure wave in the water, a.k.a. sound.

Doesn't mean it's necessarily OU;
We can also produce very small localised zones of extreme energy density, but that doesn't mean we aren't inputting the energy.
I really think the shrimp inputs all the energy needed to make its claw snap shut, which provides all the energy for the sonic pressure
wave and this in turn causes the local cavitation of water which can sometimes result in very small and localised zones of such
energy density that momentary plasma flashes can sometimes be seen.

But yes, it is a cool trick for a shrimp, certainly!