Coral Reefs

Coral reefs (also known as Sea Gardens) are reefs consisting of coral consolidated into limestone. They grow in tropical seas in the photic zone, where there is mild wave action, not so strong it tears the reef apart yet strong enough to stir the water and deliver sufficient food and oxygen. Coral reefs also need nutrient-poor, clear, warm, shallow water to grow. Coral reefs are built up from millions of skeletons from tiny animals called polyps, which are related to sea anemones.

Coral Reef Formations

Coral reefs can take a variety of forms, defined as the following;

• Apron reef — short reef resembling a fringing reef, but more sloped; extending out and downward from a point or peninsular shore.
• Fringing reef — reef that is directly attached to shore or borders it with an intervening shallow channel or lagoon.
• Barrier reef — reef separated from a mainland or island shore by a deep lagoon; see Great Barrier Reef.
• Patch reef — an isolated, often circular reef, usually within a lagoon or embayment.
• Ribbon reef — long, narrow, somewhat winding reef, usually associated with an atoll lagoon.
• Table reef — isolated reef, approaching an atoll type, but without a lagoon.
• Atoll reef — a more or less circular or continuous barrier reef surrounding a lagoon without a central island; see atoll.

Coral reefs are estimated to cover 284,300 square kilometers, with the Indo-Pacific region (including the Red Sea, Indian Ocean, Southeast Asia and the Pacific) accounting for 91.9 percent of the total. Southeast Asia accounts for 32.3 percent of that figure, while the Pacific including Australia accounts for 40.8 percent. Atlantic and Caribbean coral reefs only account for 7.6 percent of the world total (Spalding et al., 2001).

Coral reefs are either restricted or absent from along the west coast of the Americas, as well as the west coast of Africa. This is due primarily to upwelling and strong cold coastal currents that reduce water temperatures in these areas (Nybakken, 1997). Corals are also restricted from off the coastline of South Asia from Pakistan to Bangladesh (Spalding et al., 2001). They are also restricted along the coast around north-eastern South America and Bangladesh due to the release of vast quantities of freshwater from the Amazon and Ganges Rivers respectively.

Famous coral reefs and reef areas of the world include:

• The Great Barrier Reef - largest coral reef in the world, Queensland, Australia;
• The Barrier Reef of Roatán - second largest in the world, Honduras, Central America; and
• The Red Sea Coral Reef - located off the coast of Egypt.

Information Source: Wikipedia