Fig. 2

Products of Fe⁰ exposure to microorganisms from the Baltic Sea. a Cells enhanced Fe⁰ oxidation to Fe²⁺ above the background observed in cell-free (abiotic) controls. b Absolute rates of Fe²⁺-yield over 25 days in the presence or absence of cells. c In abiotic controls, electrons were recovered as H₂. d The entire community grown on Fe⁰ for eight transfers recovered electrons as methane and acetate. e Inhibition of all bacteria (including acetogens) with a mixture of antibiotics led to enhanced methanogenesis (filled line) compared to the mixed-community (dotted line). f Specific inhibition of methanogens with BES, enhanced acetogenesis (filled line) compared to the mixed-community (dotted line) (n > 5)