The Great Barrier Reef is on in the Coral Sea, off the coast of Queensland, northeast Australia. It is the largest coral reef in the world, and 1981 was selected as a World Heritage Site because of the diversity of life living in the Great Barrier Reef.
The reef has the most diversity of life, including the vulnerable and the endangered species.
Whales, dolphins and porpoise, 30 species in all have been recorded. Large dugongs live there as well as 1500 fish species
The Great Barrier Reef and its lagoon offer a wide variety of habitats for fishes and other marine organisms. The outer part of this massive reef, where the most transparent water is generally found, is divided into zones.
Typically there is a broad outer reef flat, the inner part of which may be covered with fleshy algae and the outer part with encrusting coralline algae. The reef flat is exposed during low spring tides.
At the Outer edge where the surf breaks, there is coralline algae rim, then the broad spur-and groove zone subject to strong surge from incoming waves and the scouring action of sand and rubble in the grooves from powerful water movement. The grooves may extend as deep as 20 m.
Below the spur-and-groove zone, there is usually an abrupt vertical escarpment which drops to 30 m or more a gradual slope follows this to the abyss.
Each of these zones has its characteristic assemblage of corals, algae and associated marine life. The channels and passages through the reef both shallow and deep, provide still more habitats for which current is a significant parameter.
On the sheltered side of the outer reef, as the water deepens slightly, there’s a zone of elongate patches of coral, coralline algae, about 1-2 m wide and 20 m or more in length, separated by channels.
Then a broad zone of sand grading into depths of the lagoon. Isolated on the sand substratum there are usually many small coral heads *called bommies in Australia), each a microcosm of marine organisms.
Within the deeper lagoon, a variety of coral formations occur, some rising pinnacle-like form the deep water.
Corals growing in the sheltered lagoon water are often delicately branched. Also in the lagoon are broad expanses of sea-grass beds.
Moving towards the mainland of Queensland, silty sand and mud habitats tend to dominate the lagoon floor.
The islets and larger islands of the Great Barrier Reef complex provide still more habitats such as rocky intertidal areas, sandy shores, and mangrove swamps.
Just as the outer reef zones harbour characteristic fish communities, so also do the lagoon habitats, and many of the fishes seen there will not
be found on exposed reefs.
The Great Barrier Reef is an ideal location to take a liveaboard scuba dive or snorkel trip.
Many liveaboard trips depart from the North Queensland coast for one night or a multiple of nights.