Acidovorax bacteria. Coloured scanning electron micrograph (SEM) of Acidovorax sp. bacteria coated with iron, Fe (II), crusts (orange). This bacterium is usually found in waters with a high iron content, but may also be found in soils that are highly arsenic-contaminated. It is able to precipitate the arsenic out of the soil and bind it, and due to this is being investigated as a means of reducing the amount of arsenic present in rice fields. Magnification: x6650 when printed at 10 centimetres wide.