Effect of Manual Brush Cleaning on Biomass and Community Structure of Microfouling Film Formed on Aluminum and Titanium Surfaces Exposed to Rapidly Flowing Sea Water

Metals exposed to rapidly flowing sea water are fouled by microbes that increase heat transfer resistance. Results of biochemical test methods quantitatively relating the biomass and community structure of the microfouling film on Al and Ti to heat transfer resistance across the metal surface during three cycles to free fouling and manual brushing showed that cleaning accelerates the rate of fouling measured as the loss of heat transfer efficiency and as microfouling film biomass. In three cycles of free-fouling and cleaning with a stiff-bristle nylon brush, the free-fouling communities reforming on Al became enriched in bacteria containing short-branched fatty acids as the cycling progress. Brushing removed most of the biomass, but left a residual community that was relatively enriched in a portion of the bacterial assembly containing cyclopropane fatty acids on Al and in a more diverse community on the Ti surface. No significant changes occurred in the residual microbial community structure left on Al with cleaning; it was, again, less diverse than that remaining on Ti.--CA.