Chromatium (chrome-ace-ee-um) is a red sulphur bacterium (or purple sulphur bacterium). It is found in sediments above the reduced zone. It uses 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 cell its distinctive colour. It is one of a variety of bacteria which metabolise sulphur compounds and deposit sulphur granules within the cells - both red (such as Thiocystis), and colourless (such as Beggiatoa, Achromatium, Thiovulvum, and others). Not all Chromatium are as large as this cell. Phase contrast. This picture was taken by David Patterson, Linda Amaral Zettler and Virginia Edgcomb of material from the salt marsh at Little Sippewissett (Massachusetts, USA) in Autumn, 2000 and in Spring and summer, 2001. Image copyright: D. J. Patterson, L. Amaral-Zettler and V. Edgcomb, image used under license to MBL (micro*scope).
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From the collection
Little Sippewissett salt marsh, Massachusetts, USA
|Description of Chromatium: Gram-negative, ovoid to rod-shaped bacteria, phototrophic, use ammonia as a nitrogen source. Some are found only in sulfide-containing freshwater habitats exposed to light while others may occur in marine, estuarine, and freshwater environments. Motile by means of polar flagella. Described by PERTY, 1852. Zur Kenntnis kleinster Lebensformen. Jent and Reinert, Bern I-VIII, 1-228. |