CORAL REEF DESTRUCTION and CONSERVATION
Ten percent of the world's reefs have been completely destroyed. In the Philippines, where coral reef destruction is the worst, over 70% have been destroyed and only 5% can
CORAL REEF DESTRUCTION and CONSERVATION
Ten percent of the world's reefs have been completely destroyed. In the Philippines, where coral reef destruction is the worst, over 70% have been destroyed and only 5% can be said to be in good condition. What has happened to destroy so many reefs? Human population has become very large, and earth is warming.
There are two different ways in which humans have contributed to the degradation of the Earth's coral reefs, indirectly and directly. Indirectly, we have destroyed their environment. As you read earlier, coral reefs can live only in very clear water. The large population centers near coasts has led to silting of reefs, pollution by nutrients that lead to algal growth that smothers the coral, and overfishing that has led to increase in number of predators that eat corals.
Warming of the ocean causes corals to sicken 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 color, so without the algae the coral has no color 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 gotten really bad.
The warmer water and more nutrients also encourages the growth of harmful algae on top of the coral, which kills it, because it blocks out the sun. Without the sun, the zooxanthellae cannot perform photosynthesis and so they die. Without the zooxanthellae, the coral polyps die too. This algae is usually eaten by fish, but because of over fishing, there aren't enough fish left to eat all the algae. And the pollution we dump in the ocean is just what the algae needs to grow and be healthy, which means covering and eventually killing the coral reefs.
The direct way in which humans destroy coral reefs is by physically killing them. All over the world, but especially in the Philippines, divers catch the fish that live in and around coral reefs. They sell these fish to fancy restaurants in Asia and to fancy pet stores in the United States. This would be OK if the divers caught the fish carefully with nets and didn't hurt the reefs or