Colonisation and succession of marine biofilm-dwelling ciliate assemblages on biocidal antifouling and fouling-release coatings in temperate Australia

Abstract

Ciliate assemblages are often overlooked, but ubiquitous components of microbial biofilms which require a better understanding. Ciliate, diatom and bacterial colonisation were evaluated on two fouling-release (FR) coatings, viz. Intersleek 970 and Hempasil X3, and two biocidal antifouling (AF) coatings, viz. Intersmooth 360 and Interspeed 5640, in Port Phillip Bay, Australia. A total of 15 genera were identified during the 10 week deployment. Intersleek 970 displayed the most rapid fouling by ciliates, reaching 63.3(± 5.9) cells cm⁻². After 10 weeks, all four coatings were extensively fouled. However, the toxicity of the AF coatings still significantly inhibited microbial fouling compared to the FR coatings. On all treatments, colonies of sessile peritrichs dominated the ciliate assemblage in the early stage of succession, but as the biofilm matured, vagile ciliates exerted more influence on the assemblage structure. The AF coatings showed selective toxic effects, causing significant differences in the ciliate species assemblages among the treatments.

Keywords:

• microbial biofilms
• ciliates
• microbial ecology
• microbial assemblage structure
• fouling-release
• antifouling paints

Acknowledgements

The authors would like to thank Mark Ciacic and Jim Dimas for their assistance with panel preparation, deployment and sampling on many cold Melbourne mornings; and BAE systems Williamstown for site access. The authors also wish to acknowledge the three anonymous reviewers for their valuable comments and suggestions to improve the manuscript.

Disclosure statement

No potential conflict of interest was reported by the authors.