Natural environment and conservation
Explore the Great Barrier Reef (approx. 5' 58")
Wow! Can this be real? The Great Barrier Reef looks like a fantasy paradise, with hundreds
of glowing fish darting through the coral.
Coral reefs are some of the most diverse ecosystems on earth and the Great Barrier Reef is
one of the richest in plant and animal species. This World Heritage Area is certainly the
largest coral reef system, stretching 2,300 kilometres along the northeast coast of Australia.
So… what is coral? A plant? No, coral is actually made up of thousands of tiny animals
called polyps. The Reef is formed by many colonies of different types of coral: hard corals
remove calcium carbonate from the water and make a skeleton of limestone which builds up
over hundreds of years to become the hard coral reef.
Billions of these tiny animals have built almost three thousands reefs in the Great Barrier Reef
system. In fact the Great Barrier Reef is the largest living organism on earth and the only
living structure visible from space.
Special algae living inside these reef–building polyps give the coral its colour and
photosynthesise food using energy from the sun. The algae share this food with the polyp and
in return, the polyp protects the algae: both organisms benefit, in what’s called a symbiotic
relationship.
The algae are very sensitive to pollution and changes in water temperature. Just a two degree
increase in the average sea temperature can damage the algae and they may disappear from
the coral. Without the algae and the food they provide, the coral polyp turns white and may
die, in a process called ‘coral bleaching’. This bleaching is now seen in coral reefs around the
world and is thought to be the result of global warming. Scientists are investigating how
climate change might affect the Great Barrier Reef in the long term.
The coral reefs provide habitats for thousands of other animals. There are 350 species of hard
coral, 1,500 species of fish, 800 species of starfish and sea urchins and more than 4,000
species of shellfish and their relatives. This abundance attracts larger reptiles like turtles and
sea snakes and top level predators like sharks and rays.
Cyclones and the crown–of–thorns starfish, which eat coral polyps, damage areas of the reef,
but in time, it recovers. Other threats to the reef include coastal development, over-fishing
and untreated sewage, but the good news is that the Great Barrier Reef is in the best condition
of any of the major reefs in the world because it is protected from many harmful activities.
The Great Barrier Reef is the largest World Heritage Area, covering 347,000 square
kilometres, an area roughly the size of Japan. It is also protected as a national marine park by
the Australian government and recent legislation has made the park the largest fully protected
area of ocean in the world. Extensive community consultation with groups such as fishers,
tourist operators and Indigenous peoples ensures that cultural, social and economic use of the
reef is sustainable, that this precious resource is protected and improved for the future.
While the World Heritage Area has been classified into bioregions that represent each type of
habitat, the Marine Park is divided into zones permitting different activities; shipping is
carefully controlled to prevent accidents such as oil spills and there are designated areas for
tourism, recreation and commercial fishing. On a third of the reef activities like fishing,
collecting shells, oil drilling and mining are not permitted and others require a special permit.
Some areas cannot be used at all.
Maintaining water quality is the key to reef’s survival and runoff from agriculture, urban
development and aquaculture can cause damage. Government initiatives help manage and
monitor water and a long–term action plan aims to minimise pollutants and rehabilitate
catchment areas, such as wetlands, that filter out pollutants.
Tourism is one of the most extensive activities on the reef. Guidelines used by tourism
operators reduce human impact by promoting environmentally responsible behaviour. These
guidelines comply with the law. For example, the law says people should not discharge
garbage in the park; the guidelines advise them of how they can dispose of their litter. Plastic
bags are a particular hazard as the bags can trap marine animals or be mistaken for
food…they look a lot like jellyfish!
The Great Barrier Reef really is a paradise, not just for fish, but for everyone, from
holidaymakers to scientists. Australians and visitors from around the world can all play a part
in protecting the Great Barrier Reef for the future.