, the presence of which will vary according to individual site conditions, based on factors such as temperature and humidity. The microbes work together in communities to degrade fuel and affect fuelling equipment. They form biofilms, which are complex structures of sticky, slimy polymeric substances that provide a protective habitat for microbes growing within them. These biofilms can clump with any other floating cellular material to form microbial biomass clusters that can plug filters, screens or other small orifices within the fuel system. Furthermore, these biomass layers generate organic acids that corrode metal surfaces, causing damage to fuel tanks and other ancillary equipment. If left untreated, vessels are at risk of costly damage to systems, breakdowns while at sea, and being out of service for several days.