Environment influence on antifouling coating efficiency: evidence from the Arabian Gulf and the Sea of Oman.

This study evaluated micro- and macrofouling on panels coated with Hempaguard X7 (X7), Hempasil X3 + 87500, Dynamic 9000, and Globic 9500 M versus uncoated controls over 12 months at two contrasting sites: Muscat (Sea of Oman, MS) and Abu Dhabi (Arabian Gulf, AD). We hypothesized that environmental conditions and coating type influence antifouling performance, shaping microbial community structure and subsequent macrofouling. Panels were sampled at 2, 7, and 12 months to represent early, mid, and late colonization stages. All coatings reduced micro- and macrofouling compared to controls, but effectiveness varied by site and time. AD showed significantly higher microbial densities, fouling cover, and biofouling wet weight than MS. Illumina MiSeq sequencing revealed greater microbial diversity in MS and distinct community compositions between biocidal and non-biocidal coatings. SIMPER analysis identified Nitrosovibrio and Bacillus as key genera driving differences between controls and coatings in MS and AD, respectively. X7 consistently exhibited the lowest levels of both micro- and macrofouling across sites and times. These results indicate that environmental conditions and coating properties jointly determine antifouling success and suggest microbial community structure may drive macrofouling succession. This study provides new insights into optimizing coating selection for specific environmental conditions.