Acidovorax bacterium. Coloured scanning electron micrograph (SEM) of an Acidovorax sp. bacterium (yellow) partially coated with an iron, Fe (II), crust (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: x100,000 when printed at 10 centimetres wide.