Coloured transmission electron micrograph (TEM) of the sulphur-eating bacteria, Thiocystis sp. Bacteria that use chemicals such as sulphur to convert to energy are known as chemolitho- trophs. Thiocystis lives in an anaerobic (oxygen free) environment. It is spherical or oval-shaped, with a polar flagellum that is used for movement. Some bacteria seen here, with two cells, are in the process of cell division. Thiocystis stores sulphur in granules within its cell. It belongs to the group of purple sulphur bacteria" that are found in anaerobic zones of lakes and sulphur springs, developing a purple colour. Magnification: x6,000 at 6x4.5cm size."