Montipora Tuberculosa

Coral Reef Sunscreen?

by Valeria Hester

Ever see all the crazy colors that appear on the tips of corals?  Did you ever think that those colors were actually the corals’ sunscreen which protects them and their reef mates the sun.  A fascinating discovery by researchers out of King’s College, London, have found that coral actually can produce natural sunscreen to protect itself from harsh UV rays. This discovery may also have ramifications down the road to develop a new kind of sunscreen that would better protect humans.

Coral samples were gathered from the Great Barrier Reef with the assistance of Dr. Walter Dunlap from the Australian Institute of Marine Science (AIMS) and Professor Malcolm Shick from the  University of Maine.
The team has been studying and finding out just how the genetic and biochemical compounds  are made in the coral. They are planning one day to be able to recreate them in the lab and then use them in the making of human sunscreen.

Red Planet Acropora

What is coral?

Coral is an animal that has a symbiotic relationship with the algae that lives inside it. The algae uses photosynthesis to make food for the coral.  In return, the coral gives the algae a protected place to live as well as a ride to get closer to the sun as it grows.  This partnership also sees the waste products of the corals’ respiration, CO2 used as the fuel for the algae’s photosynthesis. The process of photosynthesis needs sunlight to work, so most corals live in shallow water where light is abundantly available.  Turns out though, that this also makes them subject to sunburn.

How Do Corals Produce Sunscreen?

Dr. Paul Long, a lecturer from the Institute of Pharmaceutical Science at King’s College, London, has reported that they have been aware that coral and some algae can protect themselves from the strong UV rays of the sun, but only recently have they found out how.  What they discovered is that the algae, living in the coral makes a substance that is thought to be delivered to the coral, which then is modified into a sunscreen that benefits both the coral and algae.  Interestingly, this protects them both from UV damage, but they also found that fish feeding on the coral, also reaped the benefits of the sunscreen protection.  It is the scientists thinking that if they can figure out just how this UV protection compound is made and passed on, they could develop this substance in the lab for humans to use. This could very possibly be in the form of a pill.  Imagine popping a sunscreen pill next time you are going to the beach just like people do for sea sickness.

Acropora Tenuis Pastel colors of our corals under intense LED lighting about 3" from the corals tips.

Coral Sunscreen In The Reef Aquarium

We have known for years that as we increase the amount of light corals are exposed to in our aquariums, the more vivid the colors become.  At least until the point at which the symbiotic reaction described above can still funtion efficiently.  Given too much light, corals will ultimately die as their symbiotic algae are fried or expelled as the corals “bleach”.  Find the right balance though between normal conditions and scorching and you will be rewarded with some vibrant colors.

Coral Sunscreen’s Practical Uses

Another avenue to the King’s study is to see whether the natural sunscreen compounds could be used in the production of UV tolerant crop plants grown in harsh tropical areas.
The algae’s protection of itself and coral from UV light is – they think a biochemical pathway called the shikimate pathway, that only appears in microbes and plants. If scientist’s could take the part
of the pathway that coral naturally makes, this could be used for natural sunscreens.  Perhaps someday Third World economies could grow crops treated through the Shikimate Pathway that could otherwise not withstand the harsh sunlight of their region . This could help provide nutrient-rich food sources for impoverished countries around the world.  Until then I will continue to marvel at the coral colors that we see in our sustainably grown corals here @ Reefnation!

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