Surface colonisation by microorganisms is a ubiquitous process in the marine environment. The formation of a mature biofilm structure, which is described as an aggregate of attached cells surrounded by extracellular polymeric substances (EPS) is the final stage of colonisation. In this form, bacteria, fungi and archaea have been implicated in several deleterious effects on substrate surfaces; for example biofouling and subsequent microbiologically influenced corrosion (MIC). Although it is well documented that marine biofilms form on almost any submerged artificial or natural surface, there are still no truly effective and environmentally friendly treatment or prevention options available. Part of the reason biofilm growth and establishment cannot be adequately controlled is the lack of fundamental understanding of natural multi-species biofilm development. Polymicrobial systems give rise to complex synergistic and competitive behaviour, which is overlooked in single-species in vitro studies. So far, single-species studies have provided a great deal of information on how microorganisms assemble simple biofilms. Conversely, multi-species studies have been limited up until recently due to technique and data processing restrictions. Today, with access to advanced microscopic and molecular techniques, among others, there is greater potential for multi-species studies. It is important for the applicability of research conclusions now to move away from single-species investigations and into studies incorporating a variety of isolates which reflect marine heterogeneity. The purpose of this review is to compile the current literature and knowledge gaps surrounding multispecies biofilms, with particular focus on the development process in marine conditions on steels.
Benjamin Tuck is a PhD student at Curtin Corrosion Centre, investigating the interaction of microorganisms with metal surfaces. Ben’s work involves assessment of green, multi-function corrosion inhibitors on multi-species systems and evaluation of the attachment, adhesion and development of biofilms to subsea surfaces.