Magnetotactic Protists at the Oxic–Anoxic Transition Zones of Coastal Aquatic Environments

Magnetotactic protists of different types have been sporadically observed in a number of aquatic habitats, mainly at the oxic–anoxic transition zone of chemically stratified coastal environments and the anoxic zone. Cells of those examined contained magnetite (Fe3O4) crystals whose size and shape are close to those of magnetotactic bacteria. While some appear to biomineralize their magnetic crystals, others clearly ingest magnetotactic bacteria, with some egesting indigestible remains of these prokaryotes. Magnetotactic protists show a great potential for iron cycling in chemically stratified environments. Many questions remain to be answered regarding these interesting microorganisms.