(sid-err-owe-caps-a) is one of the iron bacteria. Iron bacteria occur in habitats which are enriched with iron and contribute in the oxidation / reduction reactions often involving reduced iron compounds which arise from anoxic habitats. The process of reduction provides iron for the bacteria. Many iron bacteria are associated with mucus and the oxidized iron is deposited within the mucus. Large numbers of iron bacteria can produce a rusty coating on surfaces, produce a reflective film on the surface of water (so that it looks as if someone has spilled oil). Iron bacteria often form a layer within the upper parts of sediments. The mucoid volcanoes of a collection of cells is evident in this picture. D DIfferential interference contrast.