NRL researcher Dr. Paul Sheehan adds, “by mathematically modeling their motion, we determined that being magnetic actually makes the bacteria much more sensitive to oxygen when in a magnetic field, so that they swim away from oxygen at much lower concentrations.”

It is as if the climber gets tired and turns around sooner when heading up the mountain, keeping her from heading too far in the wrong direction. And the stronger the magnetic field, the bigger the effect. The scientists do not yet know how the magnetic field has this affect on the bacteria, and are currently conducting additional experiments to help answer that question.
What was particularly interesting to the scientists was that the affect of being magnetic was too small for them to measure in the earth’s natural, but weak, magnetic field. “Therefore,” concludes Dr. Whitman, “the advantage to these bacteria in nature must be very small.” “But over millions of years, this very subtle advantage has somehow produced bacterial magnetism.”