The world's oceans face growing damage from human activity ­ and Australia is well positioned to become a leader in international efforts to restore them, according to the nation's senior marine scientist, Dr Nan Bray.

Dr Bray, recently arrived from California, this week took up her appointment as the new Chief of CSIRO's Division of Marine Research, based in Hobart.

"The oceans are really vulnerable, far more so than we ever suspected before, because we now know that major changes can happen quickly and at all depths," Dr Bray, who is a world authority on oceanography, explains.

"This means that changes, including human impacts, can take place far more rapidly and extensively than we once imagined. This is particularly true in the polar regions where surface waters sink to great depth and where the effects of greenhouse gases are likely to be largest.

"And because the oceans are vulnerable to major changes, that also means the earth's climate is equally vulnerable."

Dr Bray shares the concern of other marine scientists that the life of the oceans has sustained heavier damage from human activity than many people presently recognise.

"Globally, we've been overfishing, not just because of economics but because of culture and tradition, and in many cases just lack of understanding. In fact, there's growing evidence that more resources are now going into fishing than are coming out."

However while the problems sometimes seem as immense as the oceans themselves, the opportunities for Australia to understand and help solve them are equally great, she feels.

"For example, El Nino events may be triggered by the ceasing of the Indonesia throughflow which is the warm current linking the Pacific to the Indian Ocean, and the consequent buildup and spread of a warm pool of water within the Pacific.

"If we can truly understand the trigger mechanisms for El Nino we may be able to predict rainfall trends nine months ahead with the sort of precision that now applies to weather forecasts. We may also be able to forecast the severity of droughts"

At present scientists mainly use sea surface temperatures to predict El Nino -- but surface temperatures are only a single facet of a far more complex process occurring deep below the surface. Better understanding of the total process will lead to better climate forecasts. She is also confident that aquaculture being developed in Australia offers solutions to the twin problems of how to feed the world and still protect ocean fish populations.

But she says the key to successful ocean management will be to build a strong link between science and public policy.

"Scientists often speak a different language to policy makers, and we have to overcome that. Scientists need to know when to let go of the analysis, so that policy makers can use it to make sound decisions.

"And policy-makers need to understand that we will never be able to eliminate uncertainty in these large-scale predictions, though we can certainly reduce it, and in may instances can provide scientific management related advice despite the uncertainties."

Dr Bray says that, with the world's third largest ocean territory to look after, extending from the Antarctic almost to the Equator, Australia is well placed to show global leadership in the sustainable management of the seas.

"Australia is more fortunate that Europe or North America in that different groups in the community are more willing to work together. Our marine industries and scientists are closer. In some areas, such as fisheries management, Australia's approach is recognised as the world standard."

The combination of science and a supportive marine sector means that Australia is perfectly placed to become a leading exporter of marine knowledge and technology to the world, she says.

Dr Bray is a graduate of the University of California at Berkeley and the Woods Hole Oceanographic Institution-Massachusetts Institute of Technology Joint Program in Oceanography. She has worked as researcher and as director of physical oceanography at the Scripps Institution of Oceanography. Her appointment to CSIRO follows a year as visiting scientist in Hobart. Her research interests include understanding the temperature and circulation patterns in shallow and enclosed seas, the distribution of nutrients and oil spill risk assessment.

More information:
Dr Nan Bray, CSIRO Marine Research 03 6232 5212
Fran Sugden, CSIRO Marine Research 03 6232 5478