Marine sponges and sea slugs may provide an ecologically friendly answer to preventing the growth of organisms on boat hulls and pylons, according to former UQ PhD student Bronwin Stapleton.
Dr Stapleton who studied at UQ’s School of Molecular and Microbial Sciences extracted the chemical compounds from the sponges and slugs collected by members of her research group. The group was led by Associate Professor Mary Garson.
As well as advancing understanding of the marine environment her research could lead to the development of new non-toxic antifouling technologies. Damage caused by barnacles and marine organisms such as sea squirts is estimated to cost marine industries around $3.5billion a year.
Using an assay developed by collaborator Associate Professor Bernard Degnan from the School of Life Sciences Dr Stapleton tested many of the compounds on the larvae of sea squirts to determine the potential of the compounds to hinder the growth of such organisms.
“Some of the compounds tested in the study either killed or inhibited the larvae and therefore are potentially useful as ecologically friendly agents,” she said.
Her results also provide information about the chemical defence mechanisms of the creatures that produce the chemicals.
“The highly populated environment of a coral reef has many competitive pressures for space, light and nutrients and therefore the survival of marine organisms depends on their ability to defend themselves from predators and competitors,” Dr Stapleton said.
“Since sponges lack the behavioural defences of mobile animals it’s believed the toxic chemicals they produce may act as a kind of chemical warfare to their rivals.
“Our research gives clues as to how this kind of defence may be used in nature.”
Dr Stapleton travelled regularly from the St Lucia campus to UQ’s Heron Island Research Station where she collected Acanthella, Axynissa and Dysidea marine sponges and Phyllidia sea slugs. She then went back to the laboratories at UQ St Lucia to extract the chemical compounds.
This was done using a solvent that gave crude mixtures of many different substances that were separated out using a technique called chromatography until pure compounds were obtained.
The research also involved a sea slug feeding study that correlated various sea slugs with the sponges they ate.
“Isolating the compounds was significant because each new structure we find sheds light on the chemical pathways the organism uses to make compounds,” she said.
“This biosynthesis information contributes to our general understanding of how living things work. The sponge and sea slug feeding correlation was important in advancing understanding of the ecology of the ocean.”
She said some of the compounds found were novel; it was the first time they had been found in nature.
The research was funded by the Australian Research Council
For photos, contact Diana Lilley, 07 3365 2753 or d.lilley@mailbox.uq.edu.au
Media: For more information, contact Dr Bronwin Stapleton (telephone Mobile 0404872730, email: bronwinstapleton@hotmail.com) or Chris Saxby at UQ Communications (telephone 07 3365 2479, email: c.saxby@uq.edu.au).
