Remanent magnetism of sediment governs magnetofossil alignment



Most bacteria navigate by reacting to different chemical signals in their surroundings, but some bacteria have another navigational tool in their arsenal—the Earth's magnetic field. Nestled inside these magnetotactic bacteria (MTB) are organelles called magnetosomes, filled with tiny magnetic crystals and arranged in chains, which form nano-sized compass needles. When MTB die and degrade, these tiny crystals can remain in sediment and eventually become magnetic fossils called magnetofossils.