Taiwanese and US marine biologists have solved a major scientific puzzle on the bioluminescent color changes seen during the life cycles of coral, and the findings might be used to find ways to protect human skin from damage by ultraviolet rays.
In a research collaboration between the National Museum of Marine Biology and Aquarium (NMMBA) and the Scripps Institute of Oceanography in San Diego, California, scientists found that coral fluorescence changes from green in larvae to cyan in adult colonies.
According to Fan Tung-yun (樊同雲), co-author of the research report, ultraviolet radiation is harmful to coral and leads to coral bleaching and can even kill reef colonies.
Past studies determined that coral have fluorescent proteins in their cells, which absorb higher-energy light and emit fluorescent light in a lower energy field, but the changes in life development and its associated behavior had not yet been fully explained, Fan said.
For the collaboration, the museum harvested newborn stony coral larvae (Seriatopora hystrix) in waters off Kenting’s South Bay (南灣) and raised them in an aquarium.
The paper — titled Life History Changes in Coral Fluorescence and the Effects of Light Intensity on Larval Physiology and Settlement in Seriatopora hystrix — was co-authored by Fan and US counterparts, M.S. Roth and Dimitri Deheyn.
The scientists subjected newborn larvae, growing larvae and adult polyps to varying wavelengths of light radiation, including ultraviolet, blue and cyan-colored lights.
Results indicated that the change in fluorescence from green in larvae to cyan in adult colonies can be attributed to physiological traits, and the fluorescent protein is affected by environmental conditions, heat stress, as well as differences in light levels and wavelengths.
“The fluorescent proteins have a varying protective effect during the coral’s life cycle. It is likely correlated with the fact that planktonic larvae float near the ocean’s surface [and are more exposed to sunlight] while adult polyps are anchored on the seafloor at some depth [and are thus more protected],” Fan said.
“Our discovery might benefit research into the protection of human skin from ultraviolet radiation. Scientists may be able to develop new types of sun screens or protective suits to guard against solar radiation and offer people greater protection,” he added.