Long-distance electron transfer along redox gradients in the subsurface

Electron transfer (ET) is the fundamental process of life and element cycling. In the subsurface, the distance of ET determines its influencing area, normally as short as nanometers or micrometers. Here we provide direct evidence from column experiments that ET can last over 10 cm along the redox gradient in sediment columns, through a long-distance ET chain constituted by a series of short-distance electron hopping reactions involving with microbes and redox-active species like iron ions (and/or minerals) and natural organic matters. Microbial processes contribute largely under biologically active conditions, while chemical processes are important under extremely acidic/alkaline and cold conditions. Microbial and chemical processes synergistically mediate the long-distance ET process, with an estimated electron flux of 6.73 μmol e-/cm2 per day. This long-distance ET represents an overlooked but important background process influencing subsurface biogeochemical processes and remediation activities.

Methods

The data in this dataset were obtained through experimental testing, and the calculations and processing are documented within the dataset. For detailed information about the dataset, please refer to the "README" file.