The regenerative landscapes of soil are forged by minerals, soil organic matter, living organisms, gas, and water into which the webs of life are woven. Soil recycles organic molecules into bioavailable forms mainly through countless oxidation-reduction (redox) reactions, which involve a transfer of electrons between two different types of chemistry, comprising one of Earth’s most potent sources of energy. The value of these potent chemistries cannot be overstated, as the electron exchanges they enable are essential to the metabolic transformation webs of transformation that underpin myriad biological strategies and likely were critical for biogenesis around 3.5 billion years ago.

Steep redox potential gradients exist between the surface and the lower layers of undisturbed soils andsediments. In the top few millimeters of sediment, where oxygen is abundant and redox potentials are high, aerobic bacteria and other organisms like protozoans or small invertebrates metabolise glucoseinto carbon dioxide and water. As the redox potential declines with decreasing oxygen concentrationsin the deeper layers, then the aerobic organisms disappear and fermenters take over, so anaerobic metabolisms become dominant.

Providing a medium for linking life and death, soils also host the decomposition process. Rapidly turning anoxic, the interior of a rotting body produces fermentation products, which trigger the formation of bacterial electron transporting structures like nanowires. Some formations such as cable bacteria can even span long distances of more than a centimeter. The resulting electron currentsproduced by active electron transfer induce detectable measurable changes in electric fields which help us understand just how chemically active these sites are—and can persist for many hundreds, or thousands of years depending on the nature of the decomposition process.

This performative presentation uses artistic research techniques to “burrow” into the realm of redox reactions within soils. It explores the incredible transformations that exist between the soil surface and its various layers, and asks how we define the realms of life and death, and what might happen should we, the living, be able to communicate with the dead via the electrical fields they produce.

References

Living Architecture. 2020. Redox Potential Gradients in Marine Sediments. Fossil Hunters, 23 December. [online].

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Questions will be invited from the audience who can participate over CCA Annex. This event will be live-captioned and recorded.