March 2007

• Algae impacts on estuary health
• Tanami 3D map released
• Continental geochemical survey

Algae impacts on estuary health

A field survey completed by Geoscience Australia has confirmed that microscopic algae can play a critical role in maintaining the health of Australia's estuaries.

The particular type of algae, know as benthic microalagae are single-celled, underwater plants that grow on top of sediment layers in shallow estuary systems up to 2m deep. Data collected from field surveys indicates that the naturally occurring microalgae suppress the growth of water weeds by reducing the levels of available nutrients. This stops water weeds from "choking" the surrounding plant and marine life.

Samples of the water and sediments collected by scientists at various sites along the south-west coast of Australia revealed unexpected low levels of nutrients and weeds in the water, but high concentrations of microalgae at the sediment surface.

Benthic microalgae live in the top level of sediments and feed on the estuary nutrients derived from decaying organic matter. This prevents the nutrients from entering the surrounding water, thus suppressing water weed growth.

Australia's estuary systems are dynamic and delicate ecosystems, and Geoscience Australia is continuing research on a number of projects to help develop a greater understanding of these natural environments. The information is being collated and made available through OzEstuaries, a comprehensive online tool about Australia's estuarine and coastal waters.

[back to top]

Tanami 3D map released

Mining and exploration companies interested in searching for mineral deposits in the Tanami Desert now have an improved 3D map to help them evaluate the region's likelihood for untapped gold and other mineralisation.

The map has been developed by Geoscience Australia from information gathered in a deep seismic survey carried out in conjunction with the Western Australian and Northern Territory Geological Surveys under the Tanami Seismic Collaborative Research Project.

The work included four regional seismic surveys extending 724 kilometres which provided information on the region's fault system and identified correlations between known ore deposits and specific regions of increased structural complexity.

As a result of the work, Geoscience Australia has developed a significantly improved 3D map which will provide vital information on the deep structural architecture of the area to help with the evaluation of possible mineral deposits.

More information can be found in the media release on the project.

[back to top]

Continental geochemical survey

Geoscience Australia will begin a program in the near future which is aimed at gathering detailed information about the geological makeup of Australia, specifically targeting possible locations for energy related minerals.

The new regolith sampling program, known as the National Geochemical Survey of Australia (NGSA) project, forms part of the Australian Government's Onshore Energy Security Initiative announced by the Prime Minister in August 2006.

In a collaborative effort between Geoscience Australia and State and Northern Territory geoscience agencies, the NGSA will employ a cost-effective, ultra-low density sampling technique covering most of Australia to acquire actual mineral concentration measurements, especially for uranium and thorium.

More information on the NGSA project can be found in the media release from the Parliamentary Secretary to the Minister for Industry, Tourism and Resources, the Hon Bob Baldwin, MP.

[back to top]