Pistol Shrimp Creates Plasma

One of the loudest sounds in the ocean comes not from a whale, but from a creature barely an inch long. The pistol shrimp wields a specialized, oversized claw that it can cock like the hammer of a gun. When snapped shut, the claw launches a jet of water at over 60 miles per hour. This incredible speed creates a low-pressure pocket in its wake, a cavitation bubble. It is the collapse of this tiny bubble, not the impact of the claw itself, that unleashes the shrimp’s astonishing power.

The physics of this implosion are extreme. As the surrounding water rushes in to fill the vacuum, the bubble collapses with such force that for a nanosecond, the gasses inside are superheated to temperatures approaching 8,000°F, creating a tiny pocket of plasma. This process also generates a flash of light through a phenomenon called sonoluminescence—literally, light from sound. The primary weapon, however, is the powerful acoustic shockwave that radiates from the collapse, capable of stunning or even killing small fish and crustaceans from several feet away.

This natural sonic weapon is so effective that colonies of pistol shrimp can create a constant crackling din. During World War II, this collective noise was sometimes loud enough to interfere with submarine sonar, creating a natural acoustic camouflage on the seafloor. What sailors and sonar operators heard as static was actually the sound of millions of tiny bubbles collapsing with the heat of a star.