British scientists at the University of Southampton have succeeded to discover the mystery of the glow emitted by deep corals. We already knew that corals, living in shallow waters, emitted a green glow to protect themselves from sunlight. This natural phenomenon is related to the production of a protein that protects zooxanthellae unicellular algae from ultraviolet rays. This is called fluorescence of corals. Under forty meters, the corals diffuse red, orange and yellow rays. But what drives them to produce light since the sun does not reach them, and therefore they have no reason to protect themselves?
A symbiotic relationship between algae and corals
Corals and zooxanthelles live in symbiosis. Algae feed corals, but to achieve photosynthesis, they need light that is rare in the depths. So they will create theirs own light to survive. Scientist Jörg Wiedenmann, who studies the behavior of corals, has noticed that the corals that diffuse red colors live longer. Nature magazine gives the reason for this: “Blue light is more useful for photosynthesis, but red penetrates deeper into coral tissue.”
Could depths become a paradise for endangered species of corals? Unfortunately, no, some scientists say that corals not all possess the faculty of shining at depths.
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