9 Fascinating Coral Reef Ecosystem Facts

Coral reefs are absolutely integral to our environment. They provide food for fish that provide fishermen with bait that brings in the tuna harvest. Coral reefs shelter our shores. Furthermore, they provide breathtaking beauty for thousands of miles along the world’s warm coasts. Yet we know so little about them and how the coral reef ecosystem really works.
Here are nine very interesting coral reef ecosystem facts and the sad truth behind the loss of a very big part of this ecosystem.

underwater ecosystem

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1. Corals Are Symbiotic

One of the most interesting coral reef ecosystem facts is that they actually consist of two distinct types of creatures that depend entirely upon each other. The soft animal inside of the coral is called a polyp. They can be very tiny, nearly microscopic in size, or they can be huge, near one foot long. This polyp serves as a host to an algae called zooxanthellae, capable of photosynthesis that provides both creatures with the energy derived from sunlight.

The algae also gives the coral its intensely beautiful color. Ultimately, the algae on a coral reef system produce 90 percent of the energy needed by the polyps. The coral gives the algae a safe environment and some of the organic compounds that are needed for energy production in return.

2. Coral Also Depend on Waves

Coral have a symbiotic relationship with the ocean itself as well. Corals can’t come to the food, so the food has to come to them. This is where waves come in. Waves bring nutrition and oxygen into the reef system. As the waves continue to crash about the coral, they keep them clean and free of debris as well so that the algae can continue to convert sunlight into energy.

3. Coral Reefs Bring Diversity to a New Level

Moving on to coral reef ecosystem facts regarding the importance of preserving this underwater ecosystem, we need to appreciate the coral’s role in protecting biodiversity. There are hundreds of species of birds on the North American continent, yet the coral reef system can pack all of this diversity into just two acres.

That’s right, there can be just as many types of fish in a tiny section of coral reefs a there are all species of birds in North America. The most diversely populated coral reefs are in Southeast Asia, and their beauty is known worldwide. The animals that live in these reefs include shrimp, octopus, sharks, star fish, worms, sponges and more.

fish around the coral reef

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4. Only Two Types of True Plants

Coral reefs seem to be teaming with plant life, but in truth, almost all of the life that looks like plants is actually animal life. True plant life, such as grasses and trees is non-diverse in the extreme around a coral reef system. In fact, the only two types of true plants you will find there are mangrove trees and seagrass. These two species provide an abundant source of nutrition to the coral reef ecosystem however, because they grow so quickly in the fertile waters of the coral reef system.

5. Close Cousin to the Anemone

This is one of the coral reef ecosystem facts that many people may not know about. Corals are actually related to anemones and jellyfish. The three belong to a group called cnidarians , or nettle animals, due to their stinging ”tentacles”.

6. Coral Reefs Are Old

Just like our beautiful redwood forests, a coral reef ecosystem can reflect thousands of years of development. The plants and animals that exist there have been developing their uniquely diverse ecosystem for millennia. This means that every time a coral reef ecosystem is destroyed, it will likely lot fully recover in our lifetimes or even our grand children’s life times.

7. Coral Build Their Own Exoskeletons

Coral slowly form their exoskeleton over time using calcium carbonate from the sea. Eventually it builds a hard shell around the polyp that protects their soft, vulnerable bodies. At night, they sneak their stinging tentacles out of their shells to sting unwary animal life such as plankton and pull it into their digestive system. By this method, coral produce the other 10 percent of their energy requirements that their symbiotic relationship with algae cannot provide.

cnidarians exoskeleton

Image Source: Pixabay

8. Coral Depth Depends on Water Clarity

Coral reef ecosystems usually exist in very shallow waters because their symbiotic algae depends upon sunlight to survive and make energy. Once the water is deep enough that it filters out a great deal of incoming sunlight, the coral reef system cannot exist. In very, very clear water however, some reefs can grow as deep as 450 feet. This makes for a very unique ecosystem because of the depth and pressure of the water. Of course, if the water isn’t ver clear, then the coral won’t develop very deeply, so it’s important to keep our coastal waters clean and clear.

9. Coral Reefs are Natural Born Environmental Protectors

Just like trees do, coral reef systems help to scrub carbon dioxide from our environment. This means they help to reduce the green house gasses in our environment. Sea coral also help to reduce the damage caused to coastal areas by intense storms and hurricanes. This is because they help to dampen the impact of intensely strong waves, dissipating the energy before it reaches the shore. This can help to protect coastal areas from the sudden flooding caused by storm surges.

Dying Coral Reefs – Something We Should All Think About

Finally, let’s turn to sadder coral reef ecosystem facts, as statistics show that we have already lost roughly 10% of the world’s coral reef systems. This loss is devastating to our environment; we lose the benefits provided by their diversity, ability to absorb greenhouse gasses and the softening impact they have on coastal weather events. This destruction is projected to increase over the next 50 years unless humans learn how to curtail their activities that lead to pollution and runoff and curtail their overfishing.

Coral reefs depend on all the life that exists within them or visit them. Each has its own unique roll to play in the overall environment. To lose one form of life impacts all other life in the ecosystem.


Now that you know a bit more about the coral reef ecosystem, hopefully you can help to educate your friends regarding how important they are to our environment. The more we do to keep our water clean and keep dirty water from running off into our oceans, the stronger our coral reef ecosystem will be.

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