An underwater diver hovers over a coral in the ocean in Port Antonio. - FILE
Coral Reefs
Corals are extremely ancient animals that evolved into reef-building forms over the last 25 million years. Coral reefs are among the most biologically diverse regions on earth. Only tropical rainforests might provide homes for more species of plant and animal life. Even though they cover only a tiny fraction (less than .2 per cent) of the ocean's bottom, coral reefs contain more than 25 per cent of all marine life.
Types of coral
There are two main types of coral: hard coral, the major reef-building species; and soft coral, such as sea whips and sea fans. Like the tropical rainforests, coral reefs are normally found in the tropical and semitropical areas of the world where water temperatures range between 16 and 30 degrees Celsius (61 and 86 degrees Fahrenheit).
For a long time, coral was a mystery. They were called a plant animal, animal plant, and rock plant. We now know that corals are a complex mix of animal and plant life with microscopic forms of plants called algae living within the coral.
Purpose of corals
Coral reefs are important for many reasons. Most importantly, they provide protection and shelter for many different species of fish. Without coral reefs, these fish are left homeless with nowhere to live and nowhere to have their babies. In addition, coral reefs are very important because they protect coasts from strong currents and waves by slowing down the water before it gets to the shore.
Ten per cent of the world's reefs have been completely destroyed. In the Philippines, where coral reef destruction is the worst, over 70 per cent have been destroyed and only five per cent can be said to be in good condition. What has happened to destroy all of the reefs? Humans have happened.
Humans and corals
There are two different ways in which humans have contributed to the degradation of the earth's coral reefs, indirectly and directly.
Global warming caused by the greenhouse effect has raised the temperature of the oceans so high that the coral get sick and die. Even a rise of one degree in the average water temperature can hurt the coral. Due to global warming, 1998 was the hottest year in the last six centuries and 1998 was the worst year for coral.
The most obvious sign that coral is sick is coral bleaching. That is when either the algae inside die, or the algae leave the coral. The algae are what give coral its colour, so without the algae the coral has no colour and the white of the limestone shell shines through the transparent coral bodies. People have been noticing coral bleaching since the turn of the century, but only since the 1980s has it got really bad.
The direct way in which humans destroy coral reefs is by physically killing them. All over the world, divers catch the fish that live in and around coral reefs. This would be okay if the divers caught the fish carefully with nets and didn't hurt the reefs or take too many fish. But the divers want lots of fish and most of them are not very well trained at fish catching. Often they blow up a coral reef with explosives and then catch all the stunned fish swimming around. This completely destroys the reefs, killing the coral polyps that make it as well as many of the plants and animals that call it home. And the creatures that do survive are left homeless.
Question of the Week
Are Jamaicans doing enough to protect our environment, and if not, what suggestions do you have?
Please email responses to mias@uwimona.edu.jm.
