Research Paper on Coral Reefs and Their Habitat

Research Paper on Coral Reefs and their Habitat

Uploaded by Buster57 on Dec 21, 2004

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Coral Reefs

Coral reefs are complex and diverse habitat. They are perhaps on of the most interesting and colorful ecosystems to be found in the marine environment. They are very unique in many ways. Coral reefs play many important poles in the marine world. They must have certain conditions to be formed, and to survive. Lots of different sea life rely on reefs for habitat and sources of food, including some endangered species. Coral reefs are perhaps one of the greatest yet least known of wonders of our world.

The formation of a coral reef is a long and slow process, taking about a year for a reef to grow about half an inch. Many factors affect the growth of the coral. The general pattern of coral reefs is a continuous cycle of growth and destruction, resulting from the growth of the coral and destructive activities of animals and storms. This pattern serves to keep the coral reef alive and at a fairly constant level. Coral reefs must have certain conditions to survive. They must be in reasonably shallow water. Low levels of sedimentation in the water are very important too, because too many sediments in the water can block the sunlight needed for the coral reefs. Because of the sunlight required for reefs to survive, they can only grow to depths of 45 meters deep. They only form in tropical seas and areas that stay above 20 degrees Celsius. The amount of oxygen is also important. Oxygen is produced in the daytime by plant photosynthesis, but the level drops dramatically at night. Ocean waves and water movement play a part in the amount of oxygen in the water as well, this allows diffusion of oxygen into the surface levels.

There are three different kinds of coral reefs. There are fringing, barrier, and atoll. Fringing reefs are attached to margins of an island or continent, rough, table like surface, as much as 1 kilometer wide. On their seaward side they slope steeply to the ocean floor. Fringing reefs grow in shallow water near the shore and prefer dry climates with limited river runoff. There are also barrier reefs, which are similar to fringing but separated from mainland with a lagoon. The number of barrier reefs is greatly increasing due to global warming, because of the rise of the water’s level. Barrier reefs grow best where the land is sinking faster than the water. The most popular barrier reef is the Great Barrier Reef in Australia, which spans over 2,000 kilometers. The third type of coral reef is the atoll. Atolls consist of a continuous or broken ring of coral reef surrounding a central lagoon. Atolls are unique because they reach to depths of thousands of meters to the ocean floor. This presented a paradox: how can warm, shallow, sunlit water no deeper than 45 meters, create structures that reach thousands of meters to the ocean floor? In 1831, Charles Darwin set out upon the H.M.S. Beagle and circumnavigated the globe. On his journey he came up with a hypothesis on the formulation of coral islands. The essence of his hypothesis was that as a volcanic island slowly sinks, coral reefs form along the sinking flanks of it. Atolls owe their existence to sinking oceanic crust.

Coral reefs are a very important to many different species of sea life. The reefs cover only about 1% of the earth’s surface, yet contain ј of all of the earth’s species pf fish. Amongst the reefs are complex food webs, and prey relationships. Algae growing on the coral is food for many herbivores. The coral itself is food to many species. The butterfly fish eats individual coral polyps, while the Crown-of-thorns starfish eats