Giant clams for solar
The superb shades of blue and aqua coat with iridescent lips of giant clams are useful in the solar power domain. They gather the sunlight and are a source of light for the algae in there.
The algae then use the sun rays for photosynthesis that gives energy to the clam. “It ends up being a large part of the energy budget of the clams,” said study researcher Alison Sweeney, an assistant professor of physics and astronomy at the University of Pennsylvania.
Mainly, the big mollusks, that are about 4 feet, bring the sun power naturally in their shells.
The majority of iridescent cells are dead and have a similar structure to nails and hair. But the the iridescent cells of squid and giant clams live.
So, the researchers asked themselves, “What on Earth is a giant clam doing with a living iridescent cell?” Sweeney said.
Huge clams contain a dull outer shell and a weighted shell hinge useful for pointing their lips to the light. The scientists say that iridocytes have on optical function.
They went to Palau island in Philippines to research the clams. “We put this into a computer model about how we think light propagates through the clams,” Sweeney said. “[But] nobody actually believed it,” she also said.
They went back there to develop their study and measure the light inside the clams — Tridacna derasa, T. maxima and T. crocea — with a fiber-optic probe. The iridescent cells reflected a big quantity of light into the clam, more than the scientists had firstly believed, Sweeney said. Clam tissue with iridocytes contains fivefold more particles of light, called photons, deep inside the tissue than clam tissue without iridocytes does, they say.
“We’re very excited by our surprising discovery,” said study researcher Dan Morse, a professor of biomolecular science and engineering, and director of the Marine Biotechnology Center at the University of California, Santa Barbara.
“The brilliantly reflective cells of the giant clam actually redirect photons from sunlight deeper into the clam’s tissue, gently and uniformly illuminating millions of symbiotic algae that live there, so they can provide nutrients to their animal host by photosynthesis,” Morse wrote in an email to Live Science.
The configuration of the algae is also good. But if they would spread horizontally, only their top would receive light. But the clam doesn’t have this problem, as it has vertical columns.
The study is “very interesting,” Euichi Hirose, a professor of invertebrate biology at the University of the Ryukyus in Japan, told Live Science in an email.
“Now, we know the giant-clam mantle has a more sophisticated function than we expected,” said Hirose, who was not involved in the current study. “The colorful mantle reflects useless light for photosynthesis (green and yellow) and scatters useful light (red and blue) forward, and laterally, into deep tissue.”
This clams’ can become an inspiration for new green inventions. For example, traditional solar cells function properly in direct sunlight, but not when they overheat. But with this design, a reflective sheen could ensure solar cells stay cool even when they receive intense sunlight, Sweeney said.
The study can be found in the Journal of the Royal Society Interface.
