Corals Glow in the Dark to Stay Alive

Corals can glow in the dark of deep water by making a special type of fluorescent protein that captures blue light and reemits it as orange-red light, researchers discovered in a study led by the University of Southampton in the United Kingdom.

The study, released Wednesday and published in the Proceedings of the Royal Society B, said that scientists analyzed how well different light colors spread through dense layers of zooxanthellae, the symbiotic algae that are vital to coral survival, according to a University of Southampton statement.

They discovered that the orange-red light the deep water corals make has the potential to penetrate deeper into the coral's tissue and promotes the algae's photosynthesis, stated the university.

"It becomes clear that corals need special features to adjust to life in these low-light depths for the benefit of their vital photosynthetic partners and not all shallow water corals might be able to use this escape route," Jörg Wiedenmann, head of the Coral Reef Laboratory at the University of Southampton, said in the university's statement.

"This is an important step forward in understanding how the mysterious fluorescent pigments in corals work. Our findings help us to understand how the amazing diversity of coral colors structures the communities on coral reef," he continued.

The study said the "host pigments, specifically photoconvertible red fluorescent proteins, can promote coral adaptation/acclimatization to deeper-water light environments by transforming the prevalent blue light into orange-red light, which can penetrate deeper within zooxanthellae-containing tissues."

"Deep red fluorescent proteins like the ones identified in the study, don't just help corals stay alive — they're helpful in medical research as well," noted Popular Science writer Kendra Pierre-Louis.

"Individual human protein cells are too small for us to see, but by tagging them with a fluorescent protein helps scientists to watch them in action. By illuminating cells, fluorescent proteins have helped researchers track diseases like HIV and confirm the existence of cancerous cells," she added.

Coral reefs, though, are being threatened by climate change as researchers continue to find the deep water protein before they are gone, noted Popular Science.

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