Nature & Environment

Disco Clams Light Up the Sea with Rippling Show: The Secrets to Their Displays (VIDEO)

Catherine Griffin
First Posted: Jun 25, 2014 11:21 AM EDT

Disco clams are known for the rippling, rhythmic light show they display with their mirrored lips, visible even in the depths of the ocean. Now, scientists have uncovered the secret behind this light show, revealing how the clam performs this unique behavior.

Disco clams, known as Ctenoides ales, can be found in the tropical areas of the Pacific Ocean. They live in crevices on reefs and typically cluster in groups of two or more. The flashing light that the clams produce is probably to either attract prey, other clams and potential breeding partners, or is used to ward away predators.

Lindsey Dougherty, the lead researcher of this new study, has been fascinated by disco clams ever since she spotted one while diving in 2010 in Indonesia at the age of 14. Since then, she's studied the clam in order to find out how it managed to put on the light show underwater.

Actually spotting what was going on wasn't easy, though. Dougherty used high speed video, transmission electron microscopy, spectrometry, energy dispersive x-ray spectroscopy and computer modeling in order to study the detailed internal structure of the clam's lip. She quickly found out that the flashing was not, as most people thought, a form of bioluminescence. Instead, when the clam unfurls its lip a millimeter-wide mirror is revealed and reflects the ambient light.

The inside of the clam's lip is packed with tiny spheres of silica that are only about 340 nanometers in diameter. These spheres are ideal reflectors and are only revealed when the clam unfurls its lip; this means that by repeatedly furling and unfurling its lip, the clam can produce a continual rippling light show.

The findings reveal a bit more about this unusual animal behavior. Currently, the scientists are planning to study the structure of the clam's eyes in order to see whether the clams can detect the light. If they can, it may be a possible explanation as to why the clams use the light in the first place; it could be a possible way to signal one another.

The findings are published in the Journal of the Royal Society Interface.

Want to see the disco clam in action? Check out the video below, courtesy of YouTube.

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