Exploring the Role of Biofilms in the Transport and Establishment of Invasive Marine Macrofoulers
Biofilms dominated by bacteria and diatoms universally colonize submerged surfaces and mediate larval recruitment in benthic marine systems. The ability for macrofoulers to be transported by vessels and become globally established is likely affected by cues from the biofilm organisms they encounter. This study investigates how macrofoulers respond to biofilms shaped by local geography, transport processes and relocation. Biofilm assemblages in neighboring ports were largely unique to the site at which they were developed. Bacteria were primary drivers of variations among sites, and overall bacterial richness was an order of magnitude higher than has been reported for other marine environments. Diatoms drove differences between resident and transplanted biofilms and were found to survive shipping, including transport through freshwater. Different ship hull coatings and transport methods altered diatom assemblage composition. While biofilms were often unique with respect to bacteria and diatoms in this study, they affected the recruitment of < 30% of macrofoulers across the two experiments. Biofilms that were involved in recruitment and macrofouling community differences were usually from different ship hull coatings, suggesting that coating type was the underlying cause. This study proposes that macrofouling larvae are largely biofilm generalists. Such a resourceful recruitment strategy allows macrofoulers to colonize surfaces coated with a wide variety of microbial assemblages and is probably a key factor in their transport, establishment and global invasion success.