Booster biocides and microfouling.

Antifouling (AF) paints are used to prevent the attachment of living organisms to the submerged surfaces of ships, boats and aquatic structures, usually by the release of biocides. Apart from copper, organic booster biocides are the main active components in AF paints, but their use can have a negative impact on the marine environment. The direct effects of biocides on marine bacteria are poorly known. This work investigates the impact of two biocides, viz. diuron and tolylfluanid, on the growth and the viability of marine microorganisms and on their ability to form biofilms. The biocides in solution were found to inhibit growth of two strains of marine bacteria, viz. Pseudoalteromonas and Vibrio vulnificus, at a high concentration (1000 μg ml−1), but only a small effect on viability was observed. Confocal laser scanning microscopy (CLSM) showed that the booster biocides decreased biofilm formation by both bacteria. At a concentration of 10 μg ml−1, the biocides inhibited cell attachment and reduced biofi...