Novel bioactive coatings show promise in anti-fouling trials
Before deployment and after three months. (Photo:Graeme Moss, NIWA)
A three-year search by NIWA and Scion scientists has resulted in the discovery of a number of potentially useful natural extracts that protect submerged surfaces from fouling organisms. The research is a significant step in a global move away from very toxic, broad-spectrum metalbased biocides.
Research has involved an extensive screening programme using laboratory tests with fouling organisms such as invertebrates, diatoms, and macroalgal spores. Active extracts have been incorporated into special anti-fouling formulations, provided by our industry partner, Altex Coating Ltd. NIWA’s Dr Craig Depree reports that field testing is still in the early phases, but results so far indicate that a number of these natural extract formulations are completely free of fouling after three months in Wellington Harbour. In contrast, a non-treated surface can become heavily fouled with algae after just four weeks.
Field trials at NIWA’s Mahanga Bay aquaculture facility, and further refinements to the anti-fouling natural extractformulations, are ongoing. This Foundation for Research, Science & Technology programme is funded until June 2008.