Contrary to what lots of people think, coral is not a plant that attaches itself to rocks, but is actually an animal. Magnificent, awe-inspiring coral reefs, some of them extending over hundreds of kilometres, therefore consist of millions of individual animals.

This animal is a polyp.

What is a polyp?

It’s a simple organism consisting of a cylinder embellished with tentacles on its upper end. It’s part of the family of anemones, but it has the particular trait of being able to extract calcium carbonate (CaCO3) contained in the water to produce the limestone skeleton it lives in.

Simply put, it is an animal which has the extraordinary faculty of creating its own mineral shelter. But in order for coral to live and develop, different conditions are necessary.

These conditions, which are essentially light, warm water and salinity, should remain stable over time, because any change can have dramatic consequences and threaten the survival of the individual coral and thus the reefs.

For example, tropical coral reefs develop in an ideal range of temperatures between 25 and 29°, and extremes of between about 20° and 35° can be supported. Their growth is optimal at a depth of 20 metres and just under the surface of the sea, but below 60 to 70 metres, they no longer receive sufficient light and die, except for "ahermatypical" type species (see below).

The distribution of coral also depends on the energy released by waves; a calm environment enables more fragile polyps to prosper, while logically large waves only allow for the presence of the most solid species.

How does it reproduce?

Is there such a thing as female coral and male coral? No, because coral is a hermaphrodite, this means that it possesses the astounding capacity of reproducing all on its own, because it produces ovules as well as spermatozoids.

Does coral grow quickly?

As Mother Nature has made diversity one of her basic principles, there are as many answers to this question as there are species. However, the standard growth range is between a few millimetres up to tens of centimetres annually.

But the true secret of so-called “hermatypical” coral lies elsewhere…

This is found in the “agreement” it has made with microscopic algae called “zooxanthella” to help each other mutually. Due to photosynthesis, algae transform sun rays into substances that can be assimilated by the polyps to build their skeletons, and as for zooxanthella, they benefit from coral waste, so this is a perfectly harmonious relationship.

A harmonious relationship that is endangered by pollution, global warming and extreme meteorological events (Cyclones, etc.) which cause the loss of zooxanthella; coral therefore becomes a victim of bleaching and dies on a very large scale, often exceeding 50% of a colony.

But not all coral has a symbiotic relationship with an alga, why? Very simply because they do not need light to develop, they are part of the “ahermatypical” type species, which can proliferate at great depths.

Why preserve coral?

The tourism industry would reply that it represents one of the major attractions of destinations which are enriched by its exceptional beauty; nature lovers would talk about the extraordinary abundance of coral, as well as the thousands of species which interact with it.

CyberDodo would simply tell you that if only human beings, from our ancestors to our generation, had been caring enough to appreciate biodiversity that only started to be measured when it began to deteriorate dramatically, their children and their childrens children would also have benefited, and it is up to us to protect coral, like other living species, so that future generations can appreciate its beauty.

And not just by looking at photos or videos… from before…

To see the cartoon on coral, click here

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