(153c) Design and Characterization of a 3D-Printed Vertically Stacked Sensor Array for Monitoring Electrochemical Signatures of Microbial Activity in Wetland Sediment

Electron transfer processes in wetland sediment are driven by the activities of microbial communities and the surrounding environment, such as the reduction and oxidation of specific chemical compounds. To monitor the electrochemical signature arising from microbial activities, we have utilized a vertically stacked zero resistance ammetry (ZRA) sensor. ZRA is an electrochemical technique to measure electron flow between two electrodes immersed in electrolyte solution. The Vertically stacked ZRA is comprised of an array of identical graphite electrodes which are electrically connected through zero resistance ammeter. We have designed and produced the graphite electrode through additive manufacturing. We characterized the electrode by cyclic voltammetry, scanning electron microscopy (SEM) and X-ray diffraction analysis (XRD). We deployed the ZRA sensor to OWC NERR throughout the spring/summer of 2022 and 2023 and measured the current between graphite electrodes due to microbial activities in wetland sediment. We validated our result with dissolved oxygen data, surface water fluxes of CO2 and CH4, pore water and sediment analysis, and microbial community analysis. Our results indicate that the ZRA approach can be used to monitor electrochemical signature arising from microbial activities in wetland