The calcium carbonate skeleton also protects the corals from predators. Scientists have categorized coral reef into three main types: fringing reefs, barrier reefs, and atolls. Their geographic range includes both tropical and temperate climatic zones, though they are most abundant in warm, shallow water. The geological range of coral reefs is from the Middle Ordovician to modern times.
Corals play an essential economic role for many coastal human communities, as they provide a habitat for fishers, physical protection from erosion, a source of marketable goods, and a destination for tourists. Unfortunately, coral reefs globally are showing signs of ecological degradation from pollutant runoffs of chemicals and human sewage, increasing sedimentation and eutrophication, damage from ships and divers, and increasing sea temperatures and ultraviolet radiation exposure. Coral reef ecosystem health is an important indicator of the global environmental condition, as they are highly sensitive to changes in water chemistry and temperature.
The largest reef in the world measuring 2011 km in length and 72 km across at its widest point is the Great Barrier Reef. It stretches along the coast of Queensland in Australia. It is a true wonderland of color and beauty. Of the many hundreds of varieties of coral growing on the reef, the Staghorn (antler type) is one of the most common.
The Great Barrier Reef
Is a natural barrier made of
the bodies of living and dead
coral. It is normally just below
the surface of the water. It is
made of a white part containing
the bodies of zillions of polyps
which have died hundreds years
ago and a colorful part that is
the living part of the coral reef.
It is made up of living polyps.
As the world's largest coral reef ecosystem the Great Barrier Reef is home to approximately:
1.500 species of fish
400 different types of corals
4.000 species of mollusks
500 species of seaweed
215 species of birds
16 species of sea snake
6 species of sea turtle
Whales visit during the winter.
The coral itself is food for many species.
