Fig. 3. Trends in dissolved organic carbon (DOC), Fe(II), total Fe (Fe_T), and total Al (Al_T) over a 40-d anaerobic incubation period for silt + clay suspensions with control, 0-d, and spiked-addition treatments. Data for Al_T at 26 and 40 d were not obtained due to insufficient sample volume. Included are data for Fe_T from the aerobic control experiment for the 0-d treatment. Arrows denote times of dextrose addition, and error bars represent standard deviations for duplicate reactors.