Chaotic motion of magnetotactic bacteria

The motion of a magnetotactic bacterium submitted to an oscillating magnetic field was studied. The nature of the U-turn process, which occurred when the magnetic field was reversed, was investigated. It is analytically shown that this process presents a chaotic behavior. When the magnetic field is reversed the bacterium may decide if the turning will be to the right side or to the left side. Such choice is highly sensitive to the initial conditions, making it impossible to predict which side will be taken in the U-turn. (C) 2000 Published by Elsevier Science Ltd. All rights reserved.