Search for drowned coral reefs in the Gulf of Carpentaria

18 March 2005

Scientists from Geoscience Australia will embark tomorrow on the Australian National Research Facility vessel, Southern Surveyor to search for more submerged coral reefs in the Gulf of Carpentaria.

The survey, in collaboration with scientists from the CSIRO and with the support of the National Oceans Office, Department of Environment and Heritage, will use a sophisticated sonar seabed mapping system and an underwater drill to sample the physical expressions of limestone reefs in the region.

"The aim of this survey is to assess that reef growth is still occurring, the environmental conditions associated with this growth and to date past growth," said voyage leader, Dr Peter Harris. "Another key objective is to map the reefs' distribution for resource and environmental management."

In a previous marine survey in 2003 scientists discovered three large patch reefs in the southern region of Gulf of Carpentaria. These newly discovered limestone reefs are located about 100 km north-east of Mornington Island and support many live hard corals.

The reefs appear to have formed when the sea level was about 30 metres below its present position but their origin and true composition is unknown. Geoscience Australia scientists are hoping to identify if they are in fact submerged coral reefs or some other type of rocky layer. Scientists will also investigate suspicions that these features are widespread in the Gulf region. Existing bathymetric and fisheries-derived data indicates extensive distribution of hard-bottom habitats known as "untrawlable grounds" throughout the southern Gulf of Carpentaria.

If coral reefs are found to be widespread in the area, their existence will need to be included in the development of environmental plans and fisheries management goals for the region. The Gulf of Carpentaria is an important marine region and falls within the scope of plans for Australia's next regional marine resource management area.

The voyage will depart from Weipa on 21 March and return to Darwin on 12 April 2005.

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