Microorganisms on surfaces occur widely in nature. Bacteria, fungi and algae have adapted to growth on various surfaces and benefit considerably from this way of life, which is adapted to each particular location, for example on stones in a stream, and also in various kinds of piping. Their growth becomes visible to the human eye when biofilms develop excessively. Frequently the microbial growth causes damage to the material or impairs the functioning of technical equipment. If biofilms occur in a hospital clinic, for example on implants, they can cause health problems in human beings. Initially, the development of biofilms begins in a completely harmless way. Individual cells of microorganisms stick to surfaces and reproduce in the moist environment. Many types of bacteria are able to build up a layer of slime, which on the one hand provides them with protection against environmental influences. On the other hand, they enable the organisms to accumulate nutritive substances even from environments that are very low in nutrients.