Reefs are some of the world's most diverse ecosystems. They are geological features that support a diversity of marine life. In the past, much attention has been paid to our tropical coral reefs. However there is a wealth of unique marine life along our all coasts. Coral reefs are a dominant feature of Australia's warm tropical seascapes.
Coral organisms produce calcium carbonates, building their own reefs.
In our cooler southern waters, long sandy beaches with rocky reefs and coastal cliffs prevail. The range of organisms found on a reef is affected by water temperature, wave action, currents and rock or bottom type. Temperate reefs are usually formed on existing rocky outcrops, but some seaweeds such as coralline algae produce encrusting calcium that helps build up reefs. Many of the rocks that form of our reefs are made from the limestone remains of ancient marine organisms and sediments.