MARY LOUISE KELLY, HOST:
There's a sea creature that uses its own kind of fiber-optic cables to channel light to the algae living inside it. Wrap your head around that one. Science reporter Ari Daniel explains this could have implications for everything from cameras to coral.
ARI DANIEL, BYLINE: Healthy corals are really colorful and full of life, so there's no mistaking those that have bleached due to warming ocean temperatures.
DAKOTA MCCOY: The corals look white or sometimes black 'cause they've died.
DANIEL: Dakota McCoy is a biologist at the University of Chicago. She says corals normally house algae, and the two depend on one another. As waters warm, though, corals often eject their algae. That's bleaching. And yet...
MCCOY: If you snorkel over a reef after a heat wave, other animals still look healthy. So that's kind of a weird biological mystery.
DANIEL: These seemingly healthy creatures include a clam-like mollusk called a heart cockle.
MCCOY: Heart because they look like a heart shape (laughter) - these strange little clams are a little bit tougher than corals, even though they host the same type of algae.
DANIEL: McCoy suspected the heart cockle's shell might be involved.
MCCOY: Some of the shells - they look like stained glass windows. So there's material there, but light gets through.
DANIEL: McCoy wanted to know how do heart cockles make their shells transparent to get the light to their algal residents that depend on it. She gathered some cockles for a closer look.
MCCOY: So you can measure what color light passes through the shell by scanning over every wavelength of light from, you know, ultraviolet to infrared.
DANIEL: She and her colleagues found that the little windows in the heart cockle shells stream more than twice as much useful sunlight into their interiors than harmful UV radiation. In addition, some individuals have these mineral lenses beneath their little windows.
MCCOY: What they seem to do is condense light into a beam so that it's illuminating more deeply into the tissue that's doing all the photosynthesis.
DANIEL: McCoy then looked more closely at the shell's architecture. She knew it was made out of a kind of calcium carbonate, a mineral that's usually opaque in coral skeletons or other clamshells. But when McCoy used an electron microscope to study the mineral structure of the heart cockle shell, the calcium carbonate crystals were organized into these long, super narrow fibers.
MCCOY: All oriented the same direction as the direction that sunlight needs to travel to get into the shell.
DANIEL: She and her colleague, Stanford University physicist Jennifer Dionne, instantly saw something familiar.
JENNIFER DIONNE: There's a natural organism that is guiding light, essentially via its own fiber-optic bundles, to basically help its symbionts harness sunlight.
DANIEL: The researchers say that structure could inspire tiny cameras with minuscule lenses or even improve fiber-optic cable technology. The research is published in the journal Nature Communications.
MARK FARMER: Oh, I was very impressed with it.
DANIEL: Mark Farmer is a cell biologist at the University of Georgia who wasn't involved in the study. He says the results may help explain why corals tend to bleach more readily than heart cockles, a phenomenon triggered by stress. While both organisms may be exposed to the stress of warming oceans...
FARMER: By eliminating that additional stress of ultraviolet light, which can damage DNA, the cockles are perhaps less subject to the kind of stress that would lead to a bleaching event.
DANIEL: It's a difference that Dakota McCoy says could provide insights into how to help corals.
MCCOY: Can we maybe take inspiration from that to engineer new algae or new corals? - a little bit more resilient, a little bit more robust?
DANIEL: She sees in these shells more than a billion years of evolution - what she calls product design, one that allows these creatures to manipulate light.
MCCOY: You know, as well as many human engineers can.
DANIEL: For NPR News, I'm Ari Daniel.
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