What is Coral, Anyway?

How do corals live?

Gillian Ward, Reporter

Until an older age, many people don’t realize coral isn’t just pristine white rock that washes up on beaches. Not only is coral living thing, it is an animal. Yes, coral is a marine invertebrate that reproduces and even eats. Each coral is called a polyp; they can be microscopic, five inches or anywhere in-between. “Soft” corals are flexible organisms that often look like plants. “Hard” corals have a soft exoskeleton that protect their soft insides and are normally found together. These “hard” corals gather in the forest-like communities called coral reefs.

Some corals can eat by catching little marine animals with small tentacles, but others find their energy another way. The majority of corals get their energy through the process of photosynthesis, but they aren’t the ones doing it. These corals receive their energy through their symbiotic (mutually beneficial) relationship with an algae called zooxanthellae. The zooxanthellae sits inside a coral polyp and photosynthesizes to create energy for both themselves and the coral polyp. Also, the algae gives corals their beautiful, diverse colors. The coral holds up its end of the deal by providing a place for the algae (zooxanthellae) to live and by providing it carbon dioxide to process.

However, a coral may not continue to give algae shelter indefinitely. If a coral becomes stressed, it will expel the algae it once had a symbiotic relationship with. A few things that can stress coral are oxybenzone (a chemical found in sunscreen), water pollution, and the big one- a rise in water temperature. So why does it matter if the coral gets a little stressed? First, the corals lose their beautiful colors which makes them “bleached”, but even worse, they lose their energy source.

At this point the coral is not yet dead. It can survive a bleaching, but its chances of mortality and disease are greatly increased, and it no longer has food. Many corals are dying and will die because of this, that is why it is very important to know how to do your part in saving coral. You can read about how in my article titled “Why Does it Matter if Corals Die?”



-Becatoros, Elena. “More than 90 Percent of Coral Reefs Will Die out by 2050.” The Independent, Independent Digital News and Media, 13 Mar. 2017, www.independent.co.uk/environment/environment-90-percent-coral-reefs-die-2050-climate-change-bleaching-pollution-a7626911.html.

-“Corals and Coral Reefs.” Ocean Portal | Smithsonian, Smithsonian’s National Museum of Natural History, 18 Dec. 2018, ocean.si.edu/ocean-life/invertebrates/corals-and-coral-reefs.

-Ross, Rachel. “What Are Coral Reefs?” LiveScience, Purch, 24 Sept. 2018, www.livescience.com/40276-coral-reefs.html.

-“The Sunscreen We Use Is Killing Our Oceans-What Can We Do About It?” TripZilla, 26 Aug. 2018, www.tripzilla.com/sunscreen-killing-coral-reefs/84229.

-US Department of Commerce, and National Oceanic and Atmospheric Administration. “How Do Coral Reefs Protect Lives and Property?” NOAA’s National Ocean Service, 1 Mar. 2014, oceanservice.noaa.gov/facts/coral_protect.html.