Importance of Coral Reef Ecosystems

Coral reef ecosystem at Palmyra Atoll National Wildlife Refuge

When you think of coral, you probably think of colourful rocks that you might put into an aquarium or fish tank in your home. However, did you know that coral are more than just decorations. Those so-called rocks are actually the outer skeletons or exoskeletons of tiny animals called polyps. The exoskeletons are made of calcium carbonate, which the polyps continually secrete, in order to build these protective outer skeletons around themselves. Polyps can be anywhere from minuscule up to around twelve inches wide and can either grow in groups or singularly, depending on the species. The rich unique colors of coral reefs come from symbiotic algae, called zooxanthellae, which live within the coral polyp’s tissue.

Corals: builders of the reef | Natural History Museum

What are Coral Reefs

Covering about 1% of the ocean floor, coral reefs are among the most diverse ecosystems on earth and are estimated to be home to some 25% of all marine creatures with some two million species inhabiting the reefs.

Coral reefs can be found in tropical ocean waters around the globe and are made up of tiny marine invertebrate animals called polyps. These polyps are what are known as sessile, meaning they are immobile and permanently attached to one spot by their base. They grow slowly and depending on their species, form different shapes and sizes.

The Great Barrier Reef in Australia, which is the largest living structure in the world, is estimated to have started growing around 20,000 years ago.

Coral Reef Energy Source

For coral reef ecosystems, the sun is the main source of energy. Photosynthesis, algae, and plankton also contribute to the growth of coral reefs, which helps the light energy in the coral to be converted to chemical energy. This energy is passed on in the underwater ecosystem as other sea creatures eat other animals or coral reef plant life.

Coral Reefs 101 | National Geographic

Coral Reef Ecosystems Animals

There are a number of coral reef ecosystems that suit a number of different animals. Sponges, which are one of the most common parts of the ecosystem house small animals like crab and shrimp, as well as a number of small fish. Sponges appear in a number of shapes and colors and can be quite beautiful. There are also sea anemones, which are closely related to corals. Clown fish and anemone fish make their homes in the tentacles of these structures, and the anemone fish even remove parasites from the sea anemone.

Coral reef ecosystems also include bryozoans. These organisms live on the outskirts of the coral reef, and they cement the structure of the reef. Sea urchins, along with sea stars and cucumbers also live on the reef, and the sea star is actually a predator of coral polyps, which means that too many sea stars can damage the reef and leave behind only calcium carbonate. This breakdown in the food chain, affects the population of deep-sea fish in the area, and will reduce the number of large fish and game.

There are also a number of animals that live in the coral branches. Crab and lobster make up the coral reef ecosystems as well, but these crustaceans are also predators and crush sea urchins with their claws. The coral shrimp is another protective predator that removes parasites and dead skin from the fish that live in and on the reef.

If you are planning to go deep sea diving, you may even see some small reptiles that belong in the coral reef habitat. Sea snakes do not actually live on the reefs, but they live in the areas of water around the coral reef. Their fangs are very small, but the venom is potent, so it is best to admire this animal from afar. Different types of turtles live around the coral reef as well; sea turtles live in the warm water along the Great Barrier Reef.

Now that you know a little about the animals that make up the coral reef ecosystems, you will know just how to decorate a new home for your fish.