Under a microscope the chain of magnetite crystals (magnetosomes) is clearly visible inside a bacterium (Figures 1 & 2), imparting the bacterium with a magnetic dipole moment along it’s length. Each magnetosome crystal is 40-60 nm in length.
The chain of magnetite crystals acts as a ‘compass’ aligning the bacteria with the external magnetic field. In nature, this enables the bacteria to navigate with respect to the earth’s magnetic field, towards their ideal environment in the upper, micro-aerobic sediments of ponds and streams.
