Coral Fluorescence – The Deep-Sea Rave


With calcareous skeletons that serve—quite literally—as the building blocks of our beloved city, corals hold eminent importance not only in their native oceanic ecosystems, but also in our land-based society as well. Yet, when given the blue-light spotlight, they double as some of the most aesthetically appealing and photogenic creatures under the sea. Reminiscent of psychedelia, certain corals have been observed to emit fluorescent light that warp them into beautifully intense, seemingly-extraterrestrial organisms. Moreover, studies are in the midst of proving the phenomenon’s potential applications in the biomedical industry, catalyzing progress in both Alzheimer’s and cancer research. But the question of the fluorescence remains: why?

Coral reefs are already known to boast an entire spectrum of bright colors in plain white light. The reason? Pure biological science. Coral pigmentation is nothing more than a product of zooxanthellae, which are the photosynthetic algae that live in their tissues. The zoox provide each coral with oxygen, glucose, glycerol, and amino acids (yielding the corals’ renowned production of calcium carbonate) as well as aid in waste removal in return for a safe environment and the compounds needed for photosynthesis. The relationship is certainly a visible one: under stress, when the zooxanthellae are expelled by the coral’s polyps, its color fades to white—a phenomenon known as “coral bleaching.”

However, even with thriving zooxanthellae, their daylight colors dull in comparison to the neon vibrance that emanates from certain corals when the light is tinted blue, nearing ultraviolet wavelengths. Here’s how it works: when encountered, electrons turn photons of light into energy. Specific zoox pigments absorb some of this light; but when said electrons are excited, they “level up” to a higher energy state and must emit a given amount of light in order to return to their normal, stable energy level. The radiated light produces the electric, fluorescent colors that light up even the darkest depths of the sea.

The paragons of this marine fluorescence phenomenon were saved and are presently being nursed by the University of Miami’s own Aquarium Club (UMAC). The organization is run by a group of dedicated students who share a common passion for and curiosity about marine life. They invest a great deal of time and effort in the maintenance of the university’s tanks and go as far as offering advice and insight to those wishing to keep their own aquaria.

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