How big is the Great Barrier Reef?

The Great Barrier Reef is the largest coral reef in the world. It is 2, 000 kilometres long, and is 180 metres high in some places. It can can be seen from outer space, and is considered to be one of the Seven Natural Wonders of the World.

What is the Great Barrier Reef and where is it?

The Great Barrier Reef is not in fact one single reef, but a system of about 3, 000 individual coral reefs and islands stretching from Cape York to Gladstone off the Queensland coast. Coral reefs are also found in other warm Australian waters.

A coral reef is a living thing

Like any coral reef, the Great Barrier Reef can be killed because it is made up of living creatures. It has been built over many millions of years by tiny animals called polyps. The Reef is home to a huge variety of fish and other sea creatures.  Scientists have recorded more than 1,500 species (kinds) of fish living in the Great Barrier Reef.

The Barrier Reef is Protected

The Great Barrier Reef was declared a marine park in 1976, and was listed as a World Heritage site in 1981.

Threats to the Great Barrier Reef

Shipping

Ships running aground on the reef or oil spills can destroy large sections of the reef.   The quickest way for ships to take Australian coal to China and India is from ports along the Reef.  

The sea is too shallow there for the big container ships, so there has been a threat of dredging to make the sea deeper for the ships to go in and out of those ports.  There is great fear and alarm that the resulting silt could choke corals and sea grasses and kill them.

Tourism and Development

Development, building, and mining are killing the reef.   When the sea is polluted by rubbish and soil is washed into it by excavation of  and building  on the land near the reef, the coral is affected because it can only grow in clear water. 

Tourism means a lot of boating in the Reef, for people to see it and to dive from the boats. Sightseers walking on the reef kills coral.

Crown-of-thorns starfish

The crown-of-thorns starfish eats coral polyps.

This starfish has always been part of life in a coral reef, but the balance has been tipped because the main natural predator of the starfish, the triton, is greatly prized by humans for its shell. This has resulted in a drop in triton numbers, an increase in the number of starfish and the destruction of very large areas of coral.

Coral bleaching

When corals are stressed by changes in conditions such as increased water temperature or less sunlight  they expel the zooxanthellae algae living in their tissues : this algae converts sunlight into food for the polyps and also gives coral its brilliant colours. Over time this causes coral to turn completely white. Coral bleaching can cause coral to die. There has been extensive coral bleaching on parts of the great Barrier Reef on many occasions: 1998, 2002 and in 2016. Scientists believe the warmer water is a result of climate change.

Did you know?
It was explorer Mathew Flinders who surveyed and called it the ‘Extensive Barrier Reef.’

It’s a good idea to find information from more than one source!

Read more about the history of the Great Barrier Reef

https://greatbarrierreef.org/about-the-reef/history-of-the-great-barrier-reef/

Read about some of the creatures that live on the Great Barrier Reef. There are kidcyber pages about some of them - check the Animals index

https://facts.kiddle.co/Great_Barrier_Reef#Ecology

Read about the Great Barrier Reef ecosystem: an area where living things depend on each other for survival

https://greatbarrierreef.com.au/information/great-barrier-reef-food-web/

Read the kidcyber page

Coral polyps

How can you help look after the Reef?

https://www.squidsquad.com.au/reef-care.html

Watch a video about animals of the Reef

More geography games on oceans at NeoK12