Researchers have discovered a biological adaptation in heart cockles (Corculum cardissa), a species of bivalve found in the Indian and Pacific Oceans. These clams possess unique structures in their shells that act similarly to fibre optics, guiding sunlight to symbiotic algae living within them. This allows the clams to provide their algae with the necessary light for photosynthesis while simultaneously protecting them from harmful ultraviolet rays. The algae, in turn, offer the clams essential nutrients such as sugars.
Sunlight Channeling Through Shells
Heart cockles are small bivalves measuring around the size of a walnut. Their shells are covered with tiny transparent areas, which have been found to function like fibre-optic cables. This ability is attributed to the structure of aragonite, a crystalline form of calcium carbonate present in their shells. Through microscopic examinations, it was revealed that the aragonite crystals form tubes that allow light to pass through with precision while blocking damaging UV radiation.
Dakota McCoy, an evolutionary biophysicist from the University of Chicago, and her team demonstrated that the shells allow more than twice as much photosynthetically beneficial light to enter than UV light in a study published in the Nature Communications journal. This process potentially helps prevent coral bleaching and similar phenomena in clams, which can be exacerbated by climate change.
Unique Design Offers Technological Insights
The fibre-optic-like structures found in heart cockles are not only intriguing in a biological context but also present possible applications in technology. Researchers suggest that the natural light-channelling abilities of aragonite could inspire advancements in optical systems, particularly for wireless communication and precision measurement tools.
Boon Ooi, a photonics researcher at the King Abdullah University of Science and Technology, noted that mimicking these structures could lead to more efficient light collection systems, offering improvements over current fibre-optic technologies, as per a Science News report.