Collaborative research on underwater remnant volcano’s ‘secrets’

The underwater secrets of Balls Pyramid are being revealed in collaborative research which will help better inform management of the Lord Howe Island Marine Park.

The collaboration between UOW, Geoscience Australia (GA), the NSW Department of Primary Industries (DPI) and managers of the Lord Howe Island Marine Park has been focused on exploring the seafloor around Balls Pyramid, a spectacular remnant of a volcano that rises more than 500 metres out of the Tasman Sea.

Lord Howe Island is generally considered the southern limit to tropical corals in the Pacific Ocean, but the researchers hypothesised that reefs might be able to grow a little further south at Balls Pyramid.

On board Australia’s Marine National Facility research vessel, Southern Surveyor, UOW researchers, together with GA and DPI scientists, mapped in high-precision the shallow waters around this spectacular monolith, and analysed the results.

They discovered that coral had flourished in the past beyond the known southern limit to coral reef formation. To further examine the significance of the site, cores were recovered from limestone that veneers the volcanic rocks using an underwater rock drill operated by GA.

This technique helps to understand how coral reefs have responded to changes in ocean climate that occurred around 8,000 years ago when the sea level was about 30 metres lower than it is today in contrast with the marginal reefs there now.

Applying towed underwater video has provided further information about seabed habitats in the area, showing unexpected numbers of living corals growing across the broad shelf in water depths of up to 80 metres.

The results of the collaborative research, which have been published in several scientific papers, will continue to help better inform management of the Marine Park, identifying sites for monitoring, and raising further research challenges that will lead to ongoing collaborations.