Also called iron bacteria. Any of a group of bacteria that oxidize iron as a source of energy. The oxidized iron in the form Fe(OH)3 is then deposited in the environment by secretion from the bacterium. The energy obtained from these reactions is used to carry on processes in which the basic substances needed by the bacterium are manufactured. These bacteria are commonly found in seepage waters of coal and iron mining areas where iron compounds abound. Ferrobacteria are not disease producers (i.e., pathogenic), but they are important as scavengers. Sometimes they create a nuisance by multiplying so profusely in iron water pipes that they stop the flow of water. Ferrobacteria have been active through long periods of geologic time. For example, the great Mesabi iron (ore) seam of America’s Lake Superior region is thought to be a product of ferrobacteria activity.