Sunday, June 17, 2012

The Hadouken of the Undersea World

— “Hey Drew, what’s the coolest thing you learned this week?”
— “Oh, just something that made me more impressed with crustaceans than I ever thought possible.”
— “Is that a fact? Well, can you some up this whole miraculous marvel with a word that sounds too goofy to be scientifically accurate?”
— “Why, yes I can. You know, I should make it my word of the week.
shrimpoluminescence (SHRIMP-oh-loom-in-ESS-ens) — noun: sonoluminscence — that is, the emission of short bursts of light from imploding, sound-agitated bubbles — caused by the pistol shrimp or mantis shrimp.
According to Discover magazine’s blog Not Exactly Rocket Science, one sea creature has a left hook mean enough to destroy even the toughest mollusk shells and crustacean exoskeletons: the mantis shrimp. Bruiser reputation notwithstanding, it looks like the offspring of a Chinese parade dragon and that gay lobster that the B-52s once sang about. 


Also, it’s neither a mantis nor a shrimp, as the NERS article points out. Take care to remember this. You wouldn’t want to offend this creature, for he owns a set of claws that he can unfurl at speeds of 23 meters per second — about the speed of a .22 caliber bullet, according to Wikipedia and the fastest “punch” of any animal, according to NERS. And if that first punch doesn’t break through the target — say, an oyster shell or your scuba-masked face or whatever — the mantis shrimp can punch again. And again. Just from a “Hey, look what nature gave me!” perspective, that alone is impressive, but these blindingly fast attacks have surprising results in addition to reducing fellow undersea-dwellers into ceviche with brute force. According to NERS, “[The punch] creates a pressure wave that boils the water in front of it, creating flashes of light (shrimpoluminescene — no, really) and immensely destructive bubbles.”

So a real-life hadouken, more or less.

(modified from creative commons-friendly photo found here.)

Now hold on: My analogy is actually less stupid than you might think. According to Wikipedia, the shimpoluminescent attack allows the mantis shrimp to further damage its opponent without physically touching it.
The collapse of these cavitation bubbles produces measurable forces on their prey in addition to the instantaneous forces of 1,500 newtons that are caused by the impact of the appendage against the striking surface, which means that the prey is hit twice by a single strike — first by the claw and then by the collapsing cavitation bubbles that immediately follow. Even if the initial strike misses the prey, the resulting shock wave can be enough to kill or stun the prey. The snap can also produce sonoluminescence from the collapsing bubble. This will produce a very small amount of light and high temperatures in the range of several thousand kelvins within the collapsing bubble, although both the light and high temperatures are too weak and short-lived to be detected without advanced scientific equipment.
Among the myriad special moves that an animal could unleash in a fight, you probably wouldn’t imagine that bubble creation would be among the most damaging, but it apparently is. The shock waves created by the collapse of these bubbles — inertial cavitation, in sciencespeak — can create small dents in the stainless steel boat propellers, NERS claims. Amherst’s Patek Lab features some videos that offer us slow-eyed humans are best chance at seeing the mantis shrimp’s attack in motion:

Given all the build-up of preceding paragraphs, that may not look like much, but consider that the video was shot at 5,000 frames per second and is shown in the above clip at only 15 frames per second. See the little flash? That’s shimpoluminescence in action. Isn’t it strange to know that there’s a real-life equivalent of those cartoony smacks and pows you see illustrating when a punch has connected? Here’s another video:

And yes, in case you’re wondering: Mantis shrimp can break through aquarium glass — in a single strike, no less.

(Hat tip on this one: this tweet by Adam Norwood.)

Previous words of the week after the jump.

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