• Coral reefs are being destroyed by harmful human practices.coral reef image by Christian Schoettler from Fotolia.com
  
  Coral reefs provide many benefits to society. They provide a barrier that protects shorelines from dangerous storms, they provide a habitat for reef species and they are a popular tourist attraction. Unfortunately, coral reefs are in serious danger. The Global Coral Reef Monitoring Network indicates that approximately 19 percent of all coral reefs have already been irretrievably lost.
  
  

Human Pollution

• In a 2008 Reuters article entitled "Pollution Killing World's Coral Reefs," writer Jason Lange explains that human pollution is one of the main causes why coral reefs are endangered. He uses the example of Chitales, a coral reef that stretches from the coast of Mexico to Honduras. The nearby coastal city of Cancun is a popular tourist attraction. It also generates tons of human waste. The waste goes underground after being chemically treated, but it escapes through the soil into the sea. The waste releases phosphates into the water, and phosphates encourage the growth of algae. The algae chokes out the coral so that it cannot grow. As a result, the coral reef is dying.
  
  The NOAA (National Oceanic and Atmospheric Administration) website adds that other sources of human pollution such as pesticides, sediment and debris can also cause damage. Pesticides can cause slow poisoning, while sediment can smother a reef's ability to reproduce. In addition, plastic items such as fishing line and nets can entangle and break off parts of coral reefs.
  
  

Destructive Fishing Methods

• There are a number of different fishing practices that can cause serious damage to coral reefs. Cyanide fishing, for example, is a method that is used to catch reef fish alive so that the fish can later be served in high-class restaurants. A diver swims out to the coral reef with a bottle of sodium cyanide. They squirt the fish with the cyanide solution so that the animal can be easily trapped. The World Wildlife Foundation website states that 1 square meter of coral reef is killed for every reef fish that is caught this way.
  
  Another destructive fishing practice is the use of rockhopper trawlers. In this process, rubber tires are attached to fishing nets so that the nets can roll across the ocean floor. The trawls tear up and scar the coral as the trawls pass over them. This method destroys coral growth.
  
  

Rising Ocean Temperatures

• According to the Coral Reef Alliance, coral is sensitive to changes in its environment such as a rise or fall in water temperatures. Increased water temperatures can cause the polyps, which are the tentacle-shaped growths on corals, to release the algae that lives inside them. These algae are necessary for the coral to survive because they provide the coral with energy. They also give the coral their vivid colors. When the algae leaves the coral, the coral loses its color and becomes bleached. The coral will eventually die without the algae.