page_title: Fouling
section_title: Biofouling
hierarchical_section_title: Fouling / Micro fouling / Biofouling
caption_attribution_description: Porte de l'écluse du Grand-Carré (entre Lambersart et Lille dans lle Nord de la France, sur la "Deûle canalisée"). La porte et divers éléments de l'écluse (ici mise en chômage et vidée pour un entretien) sont couverts de moules zébrées (Dreissena polymorpha, espèce invasive). On distingue aussi quelques éponges d'eau douce (couleur blanc-crème),
context_page_description: Fouling is the accumulation of unwanted material on solid surfaces to the detriment of function. The fouling materials can consist of either living organisms or a non-living substance. Fouling is usually distinguished from other surface-growth phenomena in that it occurs on a surface of a component, system, or plant performing a defined and useful function and that the fouling process impedes or interferes with this function.
  Other terms used in the literature to describe fouling include deposit formation, encrustation, crudding, deposition, scaling, scale formation, slagging, and sludge formation. The last six terms have a more narrow meaning than fouling within the scope of the fouling science and technology, and they also have meanings outside of this scope; therefore, they should be used with caution.
  Fouling phenomena are common and diverse, ranging from fouling of ship hulls, natural surfaces in the marine environment, fouling of heat-transfer components through ingredients contained in cooling water or gases, and even the development of plaque or calculus on teeth or deposits on solar panels on Mars, among other examples.
context_section_description: Biofouling or biological fouling is the undesirable accumulation of micro-organisms, algae and diatoms, plants, and animals on surfaces, for example ships' hulls, or piping and reservoirs with untreated water. This can be accompanied by microbiologically influenced corrosion (MIC).
  Bacteria can form biofilms or slimes. Thus the organisms can aggregate on surfaces using colloidal hydrogels of water and extracellular polymeric substances (EPS) (polysaccharides, lipids, nucleic acids, etc.). The biofilm structure is usually complex.
  Bacterial fouling can occur under either aerobic (with oxygen dissolved in water) or anaerobic (no oxygen) conditions. In practice, aerobic bacteria prefer open systems, when both oxygen and nutrients are constantly delivered, often in warm and sunlit environments. Anaerobic fouling more often occurs in closed systems when sufficient nutrients are present. Examples may include sulfate-reducing bacteria (or sulfur-reducing bacteria), which produce sulfide and often cause corrosion of ferrous metals (and other alloys).  Sulfide-oxidizing bacteria (e.g., Acidithiobacillus), on the other hand, can produce sulfuric acid, and can be involved in corrosion of concrete.
  Zebra mussels serve as an example of larger animals that have caused widespread fouling in North America.
caption: A fragment of a canal lock in Northern France, covered with zebra mussels
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