Fig. 5: Three modes of directional long-distance ET in the subsurface.
From: Directional long-distance electron transfer from reduced to oxidized zones in the subsurface
a Mode 1: favorable long-distance ET with abundant electron mediators and weak advection/diffusion. b Mode 2: unfavorable long-distance ET with sparse electron mediators and strong advection/diffusion. c Mode 3: moderate long-distance ET with moderate electron mediators and advection/diffusion.
