Biofouling

Biofouling or biological fouling is a phenomenon affecting human-made objects in the presence of water, wherein microorganisms, plants, algae, or small animals accumulate on the objects' surfaces and impede their functionality. Such accumulation is referred to as epibiosis when the host surface is another organism and the relationship is not parasitic. Since biofouling can occur almost anywhere water is present, it poses risks to a wide variety of objects, such as watercraft hulls and equipment, medical devices and membranes, as well as to entire industries, such as paper manufacturing, food processing, underwater construction, and desalination plants.

Anti-fouling is the ability of specifically designed materials (such as toxic biocide paints, or non-toxic paints) to remove or prevent biofouling.

The buildup of biofouling on marine vessels poses a significant problem. In some instances, the hull structure and propulsion systems can be damaged. The accumulation of biofoulers on hulls can increase both the hydrodynamic volume of a vessel and the hydrodynamic friction, leading to increased drag of up to 60%. The drag increase has been seen to decrease speeds by up to 10%, which can require up to a 40% increase in fuel to compensate. With fuel typically comprising up to half of marine transport costs, antifouling methods save the shipping industry a considerable amount of money. Further, increased fuel use due to biofouling contributes to adverse environmental effects and is predicted to increase emissions of carbon dioxide and sulfur dioxide between 38% and 72% by 2020, respectively.