Relationship between bacterial community profile in biofilm and attachment of the acorn barnacle Balanus amphitrite

Abstract

The relationship between bacterial community profile in biofilm and attachment of the acorn barnacle Balanus amphitrite was investigated using a double-dish choice larval attachment bioassay and the DNA fingerprinting technique T-RFLP (terminal-restriction fragment length polymorphism). Biofilms for bioassays were either developed at 3 intertidal heights (i.e. high, mid and low) for 6 d or at the mid-intertidal height for 3 to 12 d. A clear distinction among biofilm communities at the 3 intertidal heights was revealed in the bacterial community profiles (determined by T-RFLP), biomass (determined by total organic carbon analysis), and abundance of bacteria and diatoms. Overall, cyprids of B. amphitrite preferred intertidal biofilms (i.e. 6 d old) over unfilmed surfaces for attachment. Moreover, cyprids also preferred to attach on biofilms of mid-intertidal height over high-intertidal or subtidal heights. There was no correlation between cypris attachment and any of the 3 biofilm attributes (i.e. biomass, abundance of bacteria and diatoms). Therefore, it was concluded that changes in the bacterial community profile in the biofilm affect the attractiveness of the biofilm to barnacle larvae and, thus, may determine the behavior (accepting or rejecting a surface) of settling larvae. We hypothesize that the temporal and spatial changes in the microbial community profile lead to the temporal and spatial recruitment pattern of marine invertebrates at a microscopic scale.