Summary Magnetotactic bacteria (MTB) are ubiquitous aquatic microorganisms that incorporate iron from their environment to synthesize intracellular nanoparticles of magnetite (Fe 3 O 4 ) or greigite (Fe 3 S 4 ) in a genetically controlled manner. Magnetite and greigite magnetic phases allow MTB to swim towards redox transition zones where they thrive. MTB may represent some of the oldest microorganisms capable of synthesizing...

Summary Magnetotactic bacteria (MTB) are ubiquitous aquatic microorganisms that mineralize dissolved iron into intracellular magnetic crystals. After cell death, these crystals are trapped into sediments that remove iron from the soluble pool. MTB may significantly impact the iron biogeochemical cycle, especially in the ocean where dissolved iron limits nitrogen fixation and primary productivity. A thorough assessment of their...