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Video: Coral whitening

Coral reefs are one of the richest biodiversities in the world.

These big coral structures have been formed over thousands of years in the tropical oceans.

The coral has offered shelter to numerous living beings such as fish, mollusks, shellfish, starfish, sea urchins and some algae.

What is coral?

Coral are columns of tiny sea anemones called polyps which together grow a hard, white central column.

This is their skeleton.

These tiny animals shelter numerous microscopic algae which are indispensable for the survival of the polyps and hence the development of the coral.

Coral grows in shallow and clear waters because they need the light which is used by the microscopic algae.

But the coral reefs are in danger. In fact, because of global warming, the temperature of surface waters has risen on a long-term basis in certain parts of the oceans.

And when the temperature of the water gets too high, the coral rejects the microscopic algae.

The polyps die and only the white skeleton remains.

This is what is called coral whitening.

Because coral is the essential link in the food chain, its death causes the disappearance of the animal species living there as well as their predators.

The rich biodiversity of the coral reef is degenerating in favor of a few species of algae and plant-eating fish. 

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