How Corals Create Their Own Sunshine

Jul 17, 2017 By Alexis, Young Editor
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Coral reefs are the most diverse marine ecosystem. These reef systems, made of animals called coral polyps, provide homes for a variety of marine life from octopuses to seahorses.

If you look more closely, coral even houses microscopic organisms such as Zooxanthellae, an alga that lives within coral polyps that is responsible for coral's fluorescing characteristics.

How Corals And Zooxanthellae Interact?

Coral and Zooxanthellae have a mutualistic relationship. This means that both organisms benefit from one another.

Just like humans, Coral polyps utilize cellular respiration to produce energy. Zooxanthellae cells, however, are like trees in that they utilize photosynthesis to produce energy. In order to perform these processes each organism requires a resource produced by the other such as oxygen and carbon dioxide. 

It has been found that as part of this mutualistic relationship, coral species living in shallow waters produce a bright florescence to shield the zooxanthellae from the harmful effects of the sun. However, until recently, it was unknown why coral thriving in deeper waters, where sun rays are not a threat, glow with the same bright florescence.

Why Do They Glow?

A study in Proceedings of the Royal Society B suggested that deep water corals glow with an orange-red aura in order to simulate sun rays to sustain the zooxanthellae. Orange-red light most efficiently stimulates photosynthesis.

However, in deep waters, the ocean absorbs light within this color spectrum, depriving the zooxanthellae of an important resource. Researchers concluded that deep water corals produce a florescent protein that can absorb blue light and in its place, generate an orange-red light. This light is able to penetrate through the coral tissues where the zooxanthellae live.

Fluorescence as A Solution?

In the medical field, scientists isolate proteins-- similar to the ones in deep water corals, to track cell behavior. By making cells fluoresce and taking images, they can better understand the behavior of cancerous cells as well as various diseases like Alzheimer's.

Employing a different protein, such as the one produced by deep water coral, would expand the possibilities of biomedical research.

Unfortunately, climate change is causing corals to bleach (lose color). Scientists are running out of time they may not be able to harvest the protein from deep water corals in time.  Global warming is not only affecting the biodiversity but also threatening the future of medical advancement.