Bacteria have recently been discovered directing their movements by sensing the earth's magnetic field. They contain arrays of crystals of lodestone or magnetite which they synthesize from iron in the ocean. The discovery of the same type of crystals in the abdomens of honey bees and the brains of homing pigeons suggests that nature is not oblivious to the earth's magnetic field. The biological mechanism for sensing magnetic fields has never been determined. These bacteria are capable of biologically synthesizing highly purified single domain magnets that would be very expensive to produce chemically.
The tiny perfect magnetite crystals made by the bacteria possibly could be utilized in microcircuitry. In addition, because these bacteria are attracted to metal surfaces surrounded by distortions in the earth's magnetic field, they may play a role in ship fouling. The unique physical properties of the single domain ferromagnetic crystals of magnetite produced by these bacteria are being analyzed of heavy metal storage could be important in recovering metals from ore and nuclear wastes; this is a continuing research project supported by the Office of Naval Research.
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