An automated, real-time monitoring system for determination microbial activity in anaerobic environments (sediments/saturated soils and aquifers) would allow for improved characterization (fate and transport) of organic carbon in subsurface environments. General statement of how this problem is being addressed An automated field-deployable monitoring system using a microbial fuel cell as the analytical sensor. The system will be capable of being deployed in sediment/soil and aquifers. The system will be operated in the field at a lower cost than the baseline methods. What is planned for Phase I? The scope of work includes the design and fabrication a complete sensor system capable of remote, long-term monitoring at sites. The system will include the sensor, measurement, communications and control functions. The final system will be capable of measuring subsurface microbial activity and communicate the data to a remote user via the web. Commercial Activities and other Benefits The system will decrease the cost of monitoring, and enhance the understanding of the fate and transport of organics in anaerobic environment. Additional benefits include: 1) the system can be used as a passive electron acceptor for remedial actions programs, and 2) can be used as a method of determining releases from petroleum pipelines and fracking sites, and 3) assist in monitoring natural attenuation (MNA) sites. Key Words Key words: microbial fuel cells, anaerobic microbial activity, automated in-situ monitoring, automated monitoring, anaerobic monitoring, MNA Summary for members of Congress A field-deployable monitoring system provides for the determination of the fate and transport of organic carbon in the environment.