UC Berkeley researchers study colorful disco clams

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Wednesday, July 23, 2014
UC Berkeley researchers study colorful disco clams
Researchers at UC Berkeley are studying a kind of salt water "Saturday Night Fever" -- colorful creatures known as disco clams.

BERKELEY, Calif. (KGO) -- Lindsey Dougherty wasn't even born when John Travolta was burning up the dance floor. But at the bottom of a tank, she's documenting a kind of salt water "Saturday Night Fever." It's a show complete with flashing lights generated by the unusual creatures known as disco clams.

"We have our favorites, some perform better than others," she said while gazing into the tank.

Dougherty studies the clams in her lab at the University of California. She says she first set eyes on them during a diving expedition in Indonesia.

"I'd never seen it and was immediately enamored. They're bright, flashy. I took video and I can't revoke the fact that my sister and I did some disco dancing underwater," she remembers laughingly.

And now, Dougherty has already made a breakthrough. Earlier this year she documented how the disco clam produces its flash. It's not through electricity or a chemical reaction, but by reflecting ambient light with a mirror-like coating attached to its lip like a disco ball.

"Silica nanospheres, which is highly reflective, coupled with a movement that makes them flash two times a second," Dougherty said. "Four times when a fake predator is thrown at them."

Exactly why the clams flash is still a mystery. To answer that, Dougherty and research assistant Alex Niebergall placed them in control groups, adjusting for factors like smell and light sources.

"We're hoping to see a difference in tanks where they can't see each other or smell each other," said Niebergall.

As for why the disco clams flash, Dougherty says her main hypothesis is they're either trying to bring in prey for dinner or trying to scare predators away. As the Bee Gee's might say, just stayin alive.

But lab director Roy Caldwell, Ph.D., says the clams' flashy behavior could help shed new light on the complicated ecosystems where they thrive.

"And not preserve only them," he said, "but their habitats in which they live."

And so, the team continues to document the mesmerizing show; cataloguing behavior, capturing images and just keeping the beat with these unique, if somewhat retro, creatures.

"I told some fellow students I was going to wear bell bottoms and bring a disco ball when I went to defend my dissertation. They'll probably hold me to it," said Dougherty with a smile.

In the long term, she believes the clams' reflective system could someday have commercial applications in areas such as low light optics.

Written and produced by Tim Didion.