University of Queensland researchers are conducting sophisticated studies which may save boat owners and marine authorities from having to scrape surfaces below the water line, and in future, may help prevent infection in human implants.
The anti-fouling project is studying factors which attract or repel marine invertebrates from attaching themselves to natural and man-made surfaces such as boats, pilings, and jetties.
The work may have potential in de-fouling of artificial marine surfaces which costs millions of dollars and thousands of cleaning hours each year internationally. Even large structures such as ocean liners and oil rigs are not immune from colonisation by sponges, ascidians (sea squirts), barnacles, shellfish and other marine invertebrates.
The researchers believe that improved understanding of anti-fouling processes could also be important in human medicine.
They say it could be possible to develop anti-fouling substances from marine invertebrates which deterred bacteria from settling on artificial implants.
Implants such as pacemakers, artificial joints and dialysis tubes washed by biological fluids in the body can cause serious health problems if they become colonised by bacteria. The outcomes could potentially be fatal, if untreated.
For many years, medical scientists have sought to discover new substances which could inhibit bacterial colonisation. Marine invertebrates could provide the solution.
Senior lecturer in zoology Dr Bernie Degnan and Associate Professor in chemistry Mary Garson are leading the project team in studying planktonic larvae produced by many benthic marine invertebrates that settle upon natural and man-made surfaces.
In nature, these settlement behaviours influence the community structure of a particular marine ecosystem.
'However, settlement on artificial marine surfaces is a significant problem,' Dr Degnan said.
'While the fouling of these structures appears to be indiscriminate, most marine invertebrates produce planktonic larvae that accurately differentiate and respond to different marine surfaces.
'Our project seeks to understand the processes that allow larvae to sense their environment and the molecules that inhibit or induce settlement.
'By understanding the mechanisms by which larvae perceive their surroundings, we will be able to devise natural ways to inhibit settlement on commercially-important marine structures.
'For example, it might be possible to include natural settlement inhibitors in marine paints.'
The researchers are studying the interaction of ascidian, sponge and bryozoa species found on the Great Barrier Reef near the University's Heron Island Research Station.
Dr Degnan said these species were ideal for study, as they all lived in the same habitat, often within a few centimetres of each other, naturally interacting. Previous studies indicated that the bryozoa strongly attracts the ascidian species, while some sponges strongly repel it as a defence mechanism.
Dr Garson's group has already conducted extensive research on the sponge species.
Few organisms live on sponges, suggesting they produced chemicals to defend themselves against larvae, algae and bacteria. Because of these bioactive properties, Dr Garson's group is interested in whether their chemicals might also be useful for humans.
Dr Garson heads the Chemistry Department's Marine Natural Products Group. She is currently investigating sponge chemicals known as alkaloids for potential anti-cancer, anti-malaria and anti-microbial applications.
Her Australian Research Council large grant-funded work focuses on isolating novel chemicals manufactured by the sponge.
For more information, contact Associate Professor Garson (telephone 3365 3605) or Dr Degnan (telephone 07 3365 2467).
