The Importance of Coral Reefs
Uploaded by srheric on Apr 25, 2007
The Importance of Coral Reefs
Coral Reefs are one of the world’s most beautiful habitats. They are often called the “rainforests of the ocean,” because they support such a diversity of life. They are massive underwater structures formed by the limestone skeletons of tiny invertebrate animals. These beautiful underwater structures are the largest and most diverse biological structures on earth, take thousands to years to form, yet they are being destroyed at an alarming rate.
Coral Reefs are built by accumulated skeletons of tiny animals which are mostly corals and plants. These plants are mostly coralline algae. They are built near the surface in tropical seas. When sunlight reaches the appropriate area, corals will start to grow. Over the years coral builds a reef that fringes the shoreline. This is called a fringing reef. Fringing reefs are separated from the land only by shallow water. If a reef grows farther from land, it is a barrier reef. These reefs are separated from the land by a larger lagoon. The Great Barrier Reef is the largest biological structure on earth covering over 2000 kilometers on the east coast of Australia. Atolls, on the other hand, are formed far offshore and they make a ring-shaped reef that close a circular lagoon. Occasionally a coral reef is lifted from the water making it a coral island.
The corals are made up of tiny organisms called polyps that grow together to produce the skeletons. Polyps are made up of two cell layers, the epidermis and the gastrodermis. They contain mesentery filaments to capture food, a pharynx and the columella which is found below the mouth. It is surrounded by a ring of tentacles which it uses to catch food floating in the water. Corals also get their food from single-celled plants called symbiotic algae which makes food from sunlight. The skeletal wall that surrounds the polyp is called a theca. There are two types of coral. The perforate have porous skeletons with connections between the polyps and the imperforate have solid skeletons. Corals have branches and looks just like plants and grow very slowly. If they are broken or killed by pollution, it will take the reef many years to recover.
Algae is the plant that makes most of...