Geography Concept (Coral Reefs)

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The Topic: Coral Reefs

Easier - Coral is a substance that is formed by the skeletons of sea animals. Live, healthy coral is often brightly colored. Large coral groups form rounded or branching masses. A strip or ridge of solidified coral at or near an ocean surface is called a coral reef.

 

Harder - Coral is a limestone formation formed in the sea by millions of tiny animals called polyps. Most coral polyps live together in colonies. They attach themselves to each other with a flat sheet of tissue that connects to the middle of another polyp body; half of the coral polyp extends above and the remaining half is below the connective sheet. Coral polyps remove calcium out of the sea water to build their limestone skeletons. They then deposit calcium carbonate (limestone) around their lower body halves. When the animals die, they leave limestone "skeletons" that become the foundations of barriers and ridges called coral reefs. As new polyps grow, their mass makes the limestone formation larger and larger.

Diverse coral formations may resemble branching trees, large domes, small irregular crusts, or tiny organ pipes. The living coral-forming animals color the formations in beautiful hues of tan, orange, yellow, purple, and green. Coral animals cannot live in water cooler than 65 °F (18 °C), therefore coral reefs are found mostly in warm, shallow, and tropical seas.

 

CORAL REEFS DISTRIBUTION IN INDIA

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Gulf of Kutch

The reefs here are also of fringing type around a chain of islands from Jodhiya in the north to Port Okha in the south. These are the most northern reefs in the Indian subcontinent. Because of the environmental conditions which are extreme, with a large range in temperature and salinity, at this site, the reefs are relatively less developed and harbor a low biodiversity compared to other Indian reefs. The Gulf of Kutch is also a region of high industrial development - this has been responsible for a large scale of mortality of reef corals in the recent past. The entire Gulf of Kutch reefs have now been declared as a Marine National Park.
Details of Gulf of Kutch and Coral Reef Species

Lakshadweep Islands

The coral formation consists of 10 atolls with 36 islands of which 10 are inhabited. The atolls, with the lagoon at islands cover areas ranging from 30 to 300 sq. km. The islands, however, range from less than a km to about 9 km in length. The maximum width does not exceed two km across. The health of the reefs is generally excellent, especially in the uninhabited atolls whereas in the habitant islands, human impacts, as elsewhere, are significant.
Details of Lakshadweep Islands and Coral Reef Species

Gulf of Mannar

Fringing reefs occur around a chain of 20 islands from Rameswaram in the north to Tuticorin in the south. The reefs at the northern and southern ends of the chain are partially degraded due to human activities (mining, fishing and industrial development) whereas those in the middle, because of their location away from human settlements, are in a relatively better condition. These reefs form part of the Gulf of Mannar Biosphere reserve.
Details of Gulf of Mannar and Coral Reef Species

Andaman and Nicobar Islands

These islands in the Bay of Bengal number around 500 and all of them have fringing reefs. Most of them, like those at Nicobar, have healthy reefs with a large biodiversity. However, near human settlements, such as Port Blair, impacts are readily visible. A serious natural threat to these reefs in the last two decades was infestation with the crown-of-thorns starfish.
Details of Andman & Nicobar Islands and Coral Reef Species

Others

Coral patches occur at some intertidal locations and submerged banks on the continental shelf along the west coast. Coral diversity at these sites is generally restricted to few genera. The number of coral species known so far from Indian reefs is 206.

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