(chrome-ace-ee-um) and Thiocystis
(thigh-o-cyst-is) - red sulphur bacteria (or purple sulphur bacteria). They are found in sediments above the reduced zone. Both use solar energy to assist in the oxidation of hydrogen sulphide producing elemental sulphur which is deposited within the bacterial cell as sulphur granules. Photosynthetic pigments are pink which give the cells their colour. Chromatium
are the larger spherical and elongate cells with larger sulphur granules, Thiocystis
are smaller are not easy to distinguish from the detritus. Differential Interference Contrast.