The unexpected discovery of fluorescent "rainbow" coral in the deep waters of the Red Sea could be used to help fight cancer.

The differently-colored coral glow with a bright fluorescence, and this phenomenon and has only ever been observed in shallow-water reefs, the University of Southampton reported.

"These fluorescent pigments are proteins. When they are illuminated with blue or ultraviolet light, they give back light of longer wavelengths, such as reds or greens," said Jörg Wiedenmann, Professor of Biological Oceanography and Head of the University of Southampton's Coral Reef Laboratory. "Their optical properties potentially make them important tools for biomedical imaging applications, as their fluorescent glow can be used to highlight living cells or cellular structures of interest under the microscope. They could also be applied to track cancer cells or as tools to screen for new drugs."

These-deep water mesophotic reefs exist below the limits of scuba diving missions, so studying them is extremely difficult. At these depths on the blue parts of sunlight penetrate, so the red and orange colorations of the coral came was a surprise.

"In many shallow water corals, the production of the pigments is tightly controlled by the amount and [color] of the incidental light. In the majority of our deep water species, the pigment production is essentially independent from the light exposure of the coral animals," said Cecilia D'Angelo, Senior Research Fellow at Southampton. "We found, however, that some of the pigments of these corals require violet light to switch from their nascent green [color] to the red hue of the mature pigment. This is a particularly interesting property to develop markers for advanced microscopic imaging applications."

The findings were published in a recent edition of the journal PLOS One.

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