The coral reefs are extremely old ecosystems, fragile and very rich in biodiversity. They occupy 1% of the ocean’s volume, however, are home to about ¾ of the ocean community. Their preservation is an indispensable condition for the survival of this great number of marine animals.
A symbiotic association between a sedentary animal (cnidario) and a photosynthetic plant (micro-alga) provides the basis to the largest constructions ever carried out by life on the planet. A striking example is the Great Barrier Reef in Australia. The small photosynthetic seaweed provides much of the food for the coral, while receiving protection and nutrients. Thus, both have been coexisting for millions of years, building up constructions that are home to different kinds of life and creating a real submarine forest, with a biodiversity comparable to tropical forests with an unparalleled richness in color and life, providing protection, shelter and food source. The living part of the coral is only the superficial layer and the remainder is the skeleton of this colony.
Any disturbance in its environment can curb their growth and kill many other forms of life that depend on them, directly or indirectly.
Corals are organisms that need a lot of sunlight and therefore occur mainly in tropical and semitropical seas, in very clean, transparent and warm waters. The main reason why there is no greater occurrence of coral reefs on our coast is the turbidity of coastal waters, due to the huge amount of sediment carried ashore by numerous extensive rivers. On the Brazilian coast there are some coral formations, among which stand out: Abrolhos, Atol das Rocas and Parcel Manoel Luís, all in the northeast region.
In many parts of the world the main reason for the destruction of coral reefs is linked to the sharp continental erosion caused by deforestation. Recently there was a new threat to the coral reefs, “bleaching” or whitening, that seems to be related to the greenhouse effect and consequently to the increase in temperature of the planet and seas. Besides these, other causes of destructions of the coral reefs are: the extraction to make jewelry, limestone, decoration, fish keeping, besides overfishing and water pollution.
It is in the coral reefs that we find the most colorful animals, (with bright colors.) There, they find places to hide themselves, get shelter and can, to a certain extent, display their beauty. In the oceans those who predominate are animals that seek to mimic with the colors of the place they inhabit, mingling with the environment. The next tank shows us well, the uniformity of colors.