The great barrier reef that crosses part of the Indonesian archipelago, specifically from
the south of Sulawesi to the north of the island of Flores, is the third longest in
the world, after those in Australia and Cuba.
Here the Indian and Pacific Oceans come together, creating the warmest waters in the world,
the perfect place for coral to develop.
This world of light and colour began to be formed 25 million years ago, from the accumulation
of skeletons composed of calcium carbonate of animal and vegetable origin
The coral reefs constitute the oldest of all natural communities, and the ones which contain
the greatest diversity of life on earth. Nowhere else in the world is it possible to find so
many different living beings in such close contact, and in such great numbers.
It is the most complex aquatic ecosystem on the planet.
Such variety of life makes effective visual communication necessary, to send out signals
of warning, confusion or hiding, and so the fish of the coral reef have developed extraordinary
colours and designs. This is a beautiful sea, but one which contains many dangers.
There are some four hundred types of coral and over one thousand five hundred species
of fish, some of them so incredibly beautiful it seems as if each plant or animal is trying
to outdo the others.
But this evolution has been a slower process in the reef than in other, much less stable
environments, where adaptations and extinctions are frequent,
due to important changes in the ecosystem
The stability of the reef is not, however, static. Quite the opposite, it is incredibly
dynamic. Populations of different species vary considerably, but the overall community
is maintained. The important thing is not who performs a given function, but that it
is performed by someone.
A multitude of organisms with different capacities to carry out different functions allows the
reefs to overcome setbacks that would devastate less flexible communities.
Nonetheless, with global warming and ultraviolet radiation, coral in different places around
the world is undergoing a process known as “coral bleaching”, which consists of whitening
due to the loss of the symbiotic zooxanthelae, and so many of them have atrophied lower limbs.
The origin could lie in the fact that the waters are unusually warm.
The optimum temperature for the growth of coral is between 26 and 27 degrees centigrade.
Above this temperature, the coral suffers stress which intensifies and speeds up the
bleaching process.