Multiscale insights into biofilm development on hydrophobic fouling-release coatings

Marine biofilms develop under the combined influence of environmental conditions and substrate properties. Among antifouling strategies, fouling-release coatings (FRCs) aim to promote the detachment of microorganisms considering their surface characteristics, offering an opportunity to examine how unfavorable adhesion conditions shape microfouling processes. Hydrophobic interpenetrating polymer networks (IPNs) based on tetrafluoroethyl methacrylate (TFEMA) and a commercial PDMS-based FRC were immersed for 6 months in natural seawater (Banyuls-sur-Mer, NW Mediterranean Sea), followed by exposure to moderate hydrodynamic shear stress using a rotor device. Biofilms were analyzed through a multiscale and multiomics approach combining biomass assays, microscopy, metabarcoding, and metabolomics. Community structure varied with time and substrate, but taxonomic convergence occurred during the mature stage. Notably, fungi appeared as overlooked contributors to biofilm dynamics on low-adhesion surfaces, suggesting that their roles in FRCs warrant further attention. Exposure to moderate hydrodynamic stress induced partial biomass loss while the overall community composition was largely unaffected. Metabolomic profiles further revealed coating-specific signatures, reflecting distinct physiological strategies. Together, these findings underscore how FRC surfaces modulate biofilm maturation and resilience under mechanical stress.