Acidovorax bacteria. Coloured scanning electron micrograph (SEM) of Acidovorax sp. bacteria (brightyellow) partially or fully coated with iron, Fe (II), crusts (dark yellow). 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: x20,000 when printed at 10 centimetres wide.