Coral reefs, globally are under threat. Describe the problems faced by coral reefs today. To what extent are these threats human induced? What steps, if any can be taken to either reverse damage done or protect reefs still in existence?

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Environmental Hazards

Semester 2, 2007

Weighting: 25%

Mr Brown

Due: September 14th

Words: 2865

Coral reefs, globally are under threat. Describe the problems faced by coral reefs today. To what extent are these threats human induced? What steps, if any can be taken to either reverse damage done or protect reefs still in existence?

By Vinny Shankar

Coral reefs are one of the most highly productive ecosystems in the world, with a complex ecology home to thousands of symbiotic plant, animal and bacteria species. Although they are highly productive, they are also an endangered ecosystem with the majority of threats brought about as a result of human activities or actions.

Coral reef ecosystems provide an important resource, not just because of their biological diversity and productivity, but also towards the development of tourism, and the positive economical impact they have on tropical coastal nations.

Coral reefs form when colonies of coral polyps (small aquatic animals with a tube-shaped body and a mouth surrounded by tentacles http://216.168.47.67/cis-fishnet/Crest/CRD.htm) join together in large colonies (refer figure 1.0.)

Coral reefs are divided into two categories, hard coral and soft coral.

Hard coral: this is was forms the hard solid structure that forms the reef base. It is formed from the calcareous base that the polyps secrete. The process is slow and on an average coral grows at about 1-2 mm a year, meaning it takes thousands of years for a substantial piece of coral to come about.

Soft coral: do not have skeletons, and feed by swaying in the water. They look like plants and provide homes to many small marine animals.

 

There are three different types of coral reefs:

Fringing reef: Grows in shallow water along the shore and prefers arid climates with limited river runoff. Fringing reefs are platforms that are continuous with the shore or continental shelf. That means they grow right up to the edge of the shore. An example of a fringing reef is Buccoo Reef in southwest Tobago.

Barrier Reef: Barrier reefs lie parallel to the coasts, and are separated from the shore by a wide and deep lagoon; they usually form a broken ring around islands. They grow where there is a change of sea level on the adjacent coast. Barrier reefs can also grow where the land is sinking faster than the water. The number of barrier reefs has increased worldwide as the ‘greenhouse effect’ has warmed up our oceans causing water levels to rise. An example of a barrier reef is the Great Barrier Reef in Australia.

Atoll: Atolls are reefs comprising of several small islands surrounding a lagoon. They are created when an island once surrounded by barrier reefs sinks below the ocean surface, leaving a circular reef called an atoll. Atolls are also created when water levels rise to cover an island and the surrounding reef grows to keep up with the surface of the water. An example of an atoll reef is the Bahamas Islands.

Why are coral reefs important?

  • Coral reefs (especially barrier reefs) provide a blockade from the effects of wave erosion particularly during storms. Reefs ensure that coastal development is not eroded away by the sea. Reefs provide a natural breakwater from strong waves, which is why they can shield the coast from their energy.
  • Coral reefs provide nursery ground for approximately 25 % of all marine species on the earth, even thought they only occupy 0.7 % of the ocean flow (Project aware 2000). The coral ecosystem provides a symbiotic environment.
  • Coral reefs aid in the tourism industry as many tourists come to the tropics to see coral. In 1992, coral reefs aided tourism worldwide to make $ 1.8 trillion, which is over 27 times that made by the world’s marine fisheries. (Project AWARE 2000)
  •  Coral reefs, like tropical rain forests, provide an incredible store of beneficial medicinal compounds, which help to fight illnesses such as asthma, leukaemia, viruses, cancer, and HIV. (Project AWARE 2000)
  • With some of the most spectacular marine landscapes in the world, coral reefs are an invaluable asset to local tourism and leisure industries.
  • Coral reefs are the main source of food for countless island inhabitants: 90 % of all animal protein consumed in most of the pacific island is from marine
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Coral reef formation is a long and slow process and there are a variety of different factors that corals require in order to survive.

  • Sunlight: Corals need to grow in shallow water where sunlight is able to penetrate and reach them. Corals depend on a species of algae called zooxanthellae that grows inside them. The zooxanthellae transfer some food energy directly to the coral’s polyps. If waters are too deep or too murky, the zooxanthellae will not get enough light to photosynthesize. Thus sunlight is very important if corals are to flourish. ‘Corals rarely develop deeper than 50 ...

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