Coral Reefs-

Great Barrier Reef

What are Coral Reefs?

• A reef is a ridge that is located close to the surface of oceans and seas. They could be rocks, sand, or even human made ones like ships. Coral Reefs are large ridges that are made up of living organisms called coral and limestone and other living organisms. They are classified as an AQUATIC ECOSYSTEM.

  Importance of coral reefs

  Coral reefs only cover an estimated 0.17 % of the ocean floor. However, their importance can not be underestimated. For instance they:

  • provide a habitat for aproximately 25% of all marine speices.

  • One ecoservice coral reefs provide is that coral polyps abosrb carbon dioxide as part of the carbon cycle.

  • Reefs act as natural barriers to erosion of the shoreline by causeing waves to break and reduce in energy. Worldwide, they protect 15 per cent of coastlines.

  • Coral reefs build atolls, beaches and islands which are ecosystems in their own right.

  Why are Coral Reefs Considered an Ecosysten at Risk?

  According to the World Resources Institute, in the year 2000 of the 255,300 square kilometers of coral reefs around the world 60 % were considered to be under serious threat. It is belived a combination of natural stress and human stress has created these fragile ecosystems to be at risk. However, it is the human induced modifcations that seems to be playing the larger role.

  The Great Barrier Reef- A Coral Reef Ecosystem

  Matthew Flinders first named the Great Barrier Reef in 1802. It is the longest coral reef structure in the world, and lies along the continental shelf off Queensland's east coast. The name Great Barrier Reef is misleading as it makes it sound like it is one continous ridge. In actual fact, the GBR is made up of 2900 individual reefs. Listed as a World Heritage Area in 1981, it is an excellent example of an ecosystem at risk. It is a unique ecosystem of national and international significance that is under threat from a variety of sources.

  Source: Owens, D., Paine, J., & Reid, G. (2003) Macquarie Revision Guides- HSC Geography, Macmillan: Sth Yarra. p.46