What is coral reef?

Most people think Coral is kind of a plant, or even a rock. It is neither of both. it is a living thing formed by thousand microscopic animals enclosed by calcium carbonate shells. They are tubular formed, are very small, their size is on average between 0.63-30 cm and we named them ‘polyps’. They eat like animals do, by using a mouth, which is located in the centre of their body. The mouth is surrounded by tentacles to catch food, as you can see in the anatomy image. A Coral structure behaves like as it is one creature, but actually it is formed by a huge network of connecting polyps. Those Coral colonies are forming reefs when they live in the same environment. This process of forming reef bonds is very slow and some reefs are estimated to be more than 50 million years old.

The polyp structures are built by other animals, known as ‘hard corals’. Those are invertebrate animals. Their name refers to their function: they create hard exoskeleton by the excretion of seawater into calcium carbonate. To survive the hard corals need clear water. Therefore, corals develop mostly in the shallow areas where the sun can reach them. Another reason why Coral needs the sunlight is because they live in symbiosis with algae, who only can survive in bright water. The algae are very important because they provide the energy by transposing sunlight into sugar. The algae are very tiny, we are not able to see them with a naked eye and they live within the body of the polyp. However, we can see the colars of the Coral and those are created by those algae. The complex coral colonies forming houses for more than 4000 fish species and are the most biologically rich ecosystems of the world.

There are many different types of coral.
“Some are really funny!”

          Mushroom Coral                                        Pillar Coral                                           Brain Coral