Fig. 5From: Interactions between magnetite and humic substances: redox reactions and dissolution processesMagnetic susceptibility over time for 1 g/L of a biogenic magnetite, b 13 nm magnetite, c 7 nm magnetite, and d 500 nm magnetite in the absence of HS (blue filled circles), presence of native HS (orange filled triangles) and reduced HS (grey filled squares). Standard deviations of all experiments were calculated from three independent parallelsBack to article page