Magnetotaxis is a process implemented by a diverse group of Gram-negative bacteria that involves orienting and coordinating movement in response to Earth's magnetic field.
[1] This process is mainly carried out by microaerophilic and anaerobic bacteria found in aquatic environments such as salt marshes, seawater, and freshwater lakes.
This orientation towards more favorable oxygen concentrations allows the bacteria to reach these environments faster as opposed to random movement through Brownian motion.
[3] Magnetic bacteria (e.g. Magnetospirillum magnetotacticum) contain internal structures known as magnetosomes which are responsible for the process of magnetotaxis.
In the southern hemisphere, south seeking bacteria dominate and move downwards toward the sediment (antiparallel to the magnetic field).
[6] It was originally thought by scientists that south seeking bacteria would move upwards in the north hemisphere, towards very high concentrations of oxygen.