A Low-Cost Carbon Dioxide Monitoring System for Coastal and Estuarine Sensor Networks

As the interest in marine or ocean-based carbon dioxide removal (mCDR) increases, so does the need for more spatially resolved measurement, reporting, and verification (MRV) of the CO2 sequestered (and for understanding the impacts of these environmental manipulation experiments). The mCDR/MRV community can borrow technology from the past decade’s exponential growth of interest in ocean acidification and monitoring. However, available sensors are insufficient to meet the growing demand for spatially resolved mCDR due to technological complexities, availability, and cost. For instance, in a recent review, there were few commercially available autonomous solutions for pH and pCO2 monitoring and none for total alkalinity or total dissolved inorganic carbon), and the majority of the pH and pCO2 sensors and analyzers cost well above $10,000. Proper MRV of mCDR requires high spatiotemporal resolution monitoring of the inorganic carbon system. Here we describe our efforts toward a low-cost CO2 flux or ∆pCO2 (the difference between air and water partial pressure of CO2) monitoring system intended for use in distributed sensor arrays in coastal, estuarine, and blue carbon research and in mCDR approaches.