Electromagnetic induction properties of filamentous bacteria in sediment.

Abstract

Microbial perception of spatial electromagnetic fields is essential for navigation and communication on Earth's surface system, but current understanding of this phenomenon is limited. At present, cable bacteria of the Desulfobulbaceae family have the longest known range of electron transport. In fact, the flow of electrons along these long filamentous bacteria generates an external electrostatic field, suggesting a potential for electromagnetic induction mirroring that of metallic wires. In this study, we measured the responses of cable bacteria to externally applied electric waves. We noted the formation and disappearance of square waves caused by a pair of spatially variable electric fields, generating negative and positive mirror-symmetric inductions (±1.20 mV in marine sediment) along the horizontally filamentous bacterial layer. Both seawater Candidatus Electrothrix and freshwater Ca. Electronema exhibited this electric induction. The distinct spatial boundary of bacterial induction was strictly confined within 12.5 mm below the surface of the seawater sediment. The results of this study open further avenues of research into understanding how bacteria sense and respond to spatial electromagnetic information.