Microbial biofilms facilitate adhesion in biofouling invertebrates

Much interest has focused on the role of microbial layers--biofilms--in stimulating attachment of invertebrates and algae to submerged marine surfaces. We investigated the influence of biofilms on the adhesion strength of settling invertebrates. Larvae of four species of biofouling invertebrate were allowed to attach to test surfaces that were either clean or coated with a natural biofilm. Measuring larval removal under precisely controlled flow forces, we found that biofilms significantly increased adhesion strength in the ascidian Phallusia nigra, the polychaete tubeworm Hydroides elegans, and the barnacle Balanus amphitrite at one or more developmental stages. Attachment strength in a fourth species, the bryozoan Bugula neritina, was neither facilitated nor inhibited by the presence of a biofilm. These results suggest that adhesive strength and perhaps composition may vary across different invertebrate taxa at various recruitment stages, and mark a new path of inquiry for biofouling research.