Fig. 4: Long-distance ET in the columns with different modifications.
From: Directional long-distance electron transfer from reduced to oxidized zones in the subsurface
Temporal variation of ΔEDC near the oxidized/reduced interface (locations at 1.3 and −1.3 cm) in the clay loam columns a with the inclusion of 2-cm thick quartz sand, b, c with the inclusion of 1-cm thick interlayer treated by concentrated HgCl2 and NaN3 above and below the interface, and d with the top exposed to air. “1-cm sterilized” means that a 1 cm thickness of clay loam was treated with 2 g/L HgCl2 and 19.5 g/L NaN3. The clay loam sediment (Table 1) filled in these columns was sterilized by immersing in 250 mg/L HgCl2 and 500 mg/L NaN3 prior to filling. The full schematics of these columns are displayed in Supplementary Fig. 2b, c. The photos of O2-perturbated columns were displayed in Supplementary Fig. 19. Error bars represent standard deviations of duplicate columns (mean ± standard error, n = 2, independent replicates).
