MEPS 433:85-96 (2011)  -  DOI: https://doi.org/10.3354/meps09192

ABSTRACT: Larvae of the scleractinian coral Pocillopora damicornis require a natural cue from surface-biofilm bacteria to select a suitable substratum on which to attach, metamorphose, and grow into a benthic polyp. In this study, bacteria were isolated from various reef surfaces, including different species of corals and algae, and glass slides that had been placed in the field for 1 to 2 mo. Settlement assays were conducted on monospecific biofilms of bacteria isolated from the field. Of 52 different isolates, 3 showed strongly inductive capacity, whereas the others were moderately to non-inductive. The isolates were identified by sequencing their 16S rRNA genes, and their phylogenetic relationships were then analyzed. There was no correlation between the inductive capacities of individual bacterial species and their phylogenetic relationships nor between their inductive capacities and the surfaces from which they were isolated. Varying the biofilm densities affected settlement only by a strongly inductive bacterial species. Different bacterial species may also affect the inductive capacities of other species when combined. The new data provided here broaden our understanding of the roles of bacteria in the recruitment of coral larvae.

KEY WORDS: Larval settlement · Metamorphosis · Biofilm · Marine bacteria · Coral planula · Pocillopora damicornis