The Reef

The Reef

The Great Barrier Reef is a living animal. Early scientists, however, thought it was a plant, which is forgivable. Soft corals have a plantlike growth and a horny skeleton that runs along the inside of the stem. In contrast, the hard, calcareous skeletons of stony corals are the main building blocks of the reef. There are also two main classes of reefs: platform or patch reefs, which result from radial growth, and wall reefs, which result from elongated growth, often in areas of strong water currents. Fringing reefs occur where the growth is established on sub-tidal rock, either on the mainland or on continental islands.

It's hard to imagine that the reef, which covers an area about half the size of Texas, is so fragile that even human sweat can cause damage. However, despite its size, the reef is a finely balanced ecosystem sustaining zillions of tiny polyps, which have been building on top of each other for thousands of years. So industrious are these critters that the reef is more than 1,640 feet thick in some places. These polyps are also fussy about their living conditions and only survive in clear, salty water around 18°C (64°F) and less than 98 feet deep.

Closely related to anemones and jellyfish, marine polyps are primitive, sacklike animals with a mouth surrounded by tentacles. Coral can consist of one polyp (solitary) or many hundreds (colonial), which form a colony when joined together. These polyps create a hard surface by producing lime; as they die, their coral "skeletons" remain, which form the reef's white substructure. The living polyps give the coral its colorful appearance.

The Great Barrier Reef begins south of the Tropic of Capricorn around Gladstone and ends in the Torres Strait below Papua New Guinea, making it about 2,000 km (1,240 mi) long and 356,000 square km (137,452 square mi) in area. Declared a World Heritage Site in 1981, it is managed by the Great Barrier Reef Marine Park Authority, which was itself established in 1976. Consequently, detailed observations and measurements of coral reef environments only date back to around this time.

The Great Barrier Reef attracts thousands of divers and snorkelers every year. Apart from the coral, divers can swim with 2,000 species of fish, dolphins, dugongs, sea urchins, and turtles. There are also about 400 species of coral and 4,000 species of mollusk, as well as a diversity of sponges, anemones, marine worms, and crustaceans.

Dive sites are unlimited, set around approximately 3,000 individual reefs, 300 coral cays, 890 fringing reefs, and 2,600 islands (including 618 continental islands that were once part of the mainland). Despite the vast amount of water surrounding the islands, though, freshwater is nonexistent here and thus is a precious commodity; self-sufficiency is particularly important for explorers and campers. Removing or damaging any part of the reef is a crime, so divers are asked to take home only photographs and memories of one of the world's great natural wonders.