Oxygen and Iron Isotope Studies of Magnetite Produced By Magnetotactic Bacteria

摘要

A series of carefully controlled laboratory studies was carried out to investigate oxygen and iron isotope fractionation during the intracellular production of magnetite (Fe_3O_4) by two different species of magnetotactic bacteria at tem- peratures between 4 and 35 deg. C under microaerobic and anaerobic conditions. No detectable fractionation of iron isotopes in the bacterial magnetites was Observed. However, oxygen isotope measurements indicated a temperature- Dependent fractionation for Fe_2O_4 and water that is consistent with that Observed for Fe_3O_4 produced extracellularly by thermophilic Fe~3+ -reducing