Purple non-sulfur bacteria
Rhodospirillum
Azospirillum
Magnetospirillum
Phaeospirillum
Rhodocista
Rhodospira
Rhodothalassium
Rhodovibrio
Roseospira
Skermanella
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The
purple non-sulfur bacteria are a family (Rhodospirillaceae) of phototrophic
bacteria that
photosynthesize using
bacteriochlorophylls a and
b in anoxic environments, such as the bottom mud of ponds and other stagnant water, although they are able to survive in air. The reducing agent involved is
hydrogen rather than water, so
oxygen is not produced.
Members of the family range in color from purple to red and brown, with shapes including spherical, rod, vibrio, and spiral (
Rhodospirillum).
The genus
Magnetospirillum is magnetotactic; using chains of tiny crystals of
magnetite, these bacteria are able to use the Earth's
magnetic field to return to the bottom of a pond (since the magnetic lines of force run downwards as well as to the north or south). Similar magnetite chains found in
Martian meteorites have been suggested as evidence of life of Mars.
