The Reef in the Maldives
Reef exists only in the tropical sea, where water is warm and shallow.
This spectacular and colourful natural wall is made up by skeletons of dead corals and madreporas, joined together by calcareous algae.
This beautiful sea-garden is one of the richest and oldest ecosystem on the earth: some types of corals take hundreds of years before growing and transforming into beautiful ocean flowers.
The reef grows towards the surface.
Its top is made by polyps constructing their skeleton on those of their precursors. Also the horny corals and the so-called gorgonians, which don’t have a calcareous skeleton, live in this colourful place.
Reefs are mainly populated by benthic, vertebrate organism (corals, madreporas, anemones, jellyfishes, sponges, starfishes, etc). There are many kinds of coral which can assume different consistencies and shapes, such as mushrooms, daisies, trees etc. The black coral, for example, looks like a bunch made up by many thin branches, the orange coral of the Indian and Pacific ocean looks like an embroidered fan.
The cerebral coral is like a round stone and is very similar to the human brain; the gorgonian looks like a fan. Both belong to the soft corals.
A hard coral is made up by a colony of very small polyps similar to anemones.
To protect their bodies, they create a calcareous shell (the skeleton) with the help of mono-cellular micro-algae, with which they live in symbiosis. The algae explain why coral prefers to live in clear, clean and shallow waters, as they
need sun light to survive. The algae contribute in feeding the corals which can capture the plankton with the tentacles.
Unfortunately all over the world 60% of the corals is threatened by the excessive fish exploitation, by destructive fishery techniques and by the ever growing environmental pollution.
Corals are very sensitive to the atmospheric heating: with a minimum increase of the water temperature polyps start expelling their symbionts and the sea flowers lose their particular colour.
The phenomenon of coral whitening is called “coral bleaching”.
Unfortunately in 1998, the Maldives was attacked by the Nino, a climatic phenomenon that caused the heating of the water superficial temperature and the consequential corals death.
When temperature came back to normal values, the coral started growing again. Luckily it is easy to see new coral creations growing year after year and that are re-colouring the reef of the Maldives.