Hard Corals

Sydney is not known for its hard corals. There are quite a few corals growing on rocks. The reefs around here are usually referred to as sponge gardens as they are more dominant. The two larger corals are SYdney Stony Coral and Sydney Plate Coral.

Quite often, sponge gardens can be much more colourful that many tropical reefs, especially deep water sponge gardens deeper tham 25 metres. Many of the sponges have brilliant vivid colours created by tiny marine algal plants living within the sponge tissues..

 

 
plate coral Close up
Sydney Plate Coral has weak ridges. It is known as Coscinasterae. Close up of the Polyps of Sydney Plate Coral out feeding. The polyps are 5 to 6 mm across. Notice how a fleshy material grows between each polyp and that the coral home is elevated.
Sydney Stony coral Yellow Daisy coral
Sydney Stony coral, Siderasterae, is usually a brown colour. This green form is less common but is due to different symbiotic algae living within the tentacles. Sydney stony coral is renowned for flourescing in ultra violet light. Yellow Daisy coral is an Ahermatypic coral living on the roofs and walls of caves. This is a coral that does not have symbiotic algae growing within its flesh. Learn how its corallite is one of the most intricate treasures in the ocean.