Microbe-powered sensors

Soil has a remarkable capacity to sequester carbon, and expanding soil carbon stores could prove instrumental to achieving a carbon-neutral future. However, there is currently no effective way to monitor the cycle of carbon building up and breaking down in soil over large areas in real time, to better measure carbon sequestration capabilities. This project aims to develop and deploy microbial fuel cell-based sensors that monitor soil microbial activity, which serves as an indicator of soil organic carbon (SOC) levels. Microbial fuel cells are bioelectrochemical systems that produce small amounts of power due to the activities of a certain class of naturally occurring microbes known as exoelectrogens. These exoelectrogens are ubiquitous in nearly all soils and produce a spare electron as a byproduct of their typical respiration activities. If we place electron acceptors in the soil (carbon felt electrodes) and place a load in between the electrodes (a resistor), then the microbes donate their spare electrons to the electrodes, and electrical signals are generated. The voltage and current of these electrical signals change in response to environmental conditions. Our preliminary work finds that electrical signals have a non-trivial correlation to the organic carbon content of the soil. We hypothesize that these relationships can be used to develop a first-of-its-kind soil carbon sensor.

We are working on establishing correlations between microbial activity and SOC levels as an innovative method for monitoring carbon sequestration activities. Our sensors will empower farmers to maximize carbon storage, optimizing land, water, and labor use on their farms. By introducing accessible and affordable technologies, we aim to create a measurable impact on reducing CO2 emissions. Improving carbon sequestration activities can mitigate up to 0.6 Pg Carbon. Current methods for monitoring soil carbon are often too expensive or labor-intensive for farmers to adopt, and we seek to address this issue with our sensing technologies.

To learn more, see:

Is it time to start moving soil microbial fuel cell research out of the lab and into the field?
Time-series forecasting of microbial fuel cell energy generation using deep learning
Soil-Powered Computing: The Engineer’s Guide to Practical Soil Microbial Fuel Cell Design
The Future of Clean Computing May Be Dirty
Early Characterization of Soil Microbial Fuel Cells
Farming Electrons: Galvanic vs. Microbial Energy in Soil Batteries
Towards Microbial Fuel Cell Powered Backscatter Tags for Low-Cost In-Ground Soil Moisture Sensing\