Great Barrier Reef – Island of Reefs
The Great Barrier Reef is one of the great natural wonders of the world, the largest coral reef on Earth. It is a system of many individual reefs and small islands. Altogether there are 2,900 individual reefs. It lies in the Pacific Ocean off the coast of Queensland in northeastern Australia. From north to south its length is more than 2,000 kilometers.
The Great Barrier Reef was formed over millions of years from mounds of coral. There are at least 300 types of hard coral. The corals died but their shells remained, and other corals grew on top of it. Over those millions of years, the corals cemented together and were covered with underwater plants, debris from the ocean. Most of the reefs are under water (bare during low tides).
The sea life of the reef is extraordinary. And there are more than 1,500 species of saltwater fish. Besides the 400 types of coral, there are anemones, sponges, snails, worms, lobsters, prawns, jellyfish, crayfish, giant clams, and dugongs.
By the way, there are also hundreds of different birds in the area. They are colorful and have unusual shapes.
In 1981 the Great Barrier Reef was named a World Heritage site. It is often referred to the largest structure ever built by living things. It can be seen from space.
The Great Barrier Reef is a tourist attraction and a protected marine environment. It is known to mankind for a long time: it is used by Australian Aborigines and Torres Strait Islanders, being an important part of the culture and spirituality of local groups. The National Foundation named Great Barrier Reef Marine Park is the visiting card of Queensland.
The vulnerability of coral reef ecosystems is due to the fact that special conditions are required for coral growth. The water temperature should not be lower than 17.5 ° C (ideal temperature is 22-27 ° C). This explains why the Great Barrier Reef did not spread southward beyond the tropic of Capricorn. The water in which the corals grow must have a certain salinity, so the reef ends at the coast of New Guinea, where the Flay River brings a large amount of fresh water into the ocean.