Field Evaluation of a Low-cost Multi-gas Biogeochemical Sensor in the Subpolar North Atlantic

Increasing environmental awareness, tightening resource budgets, and a greater interest in citizen science have magnified the demand for compact, low-cost sensors. Inexpensive off-the-shelf sensors enable the creation of affordable and easy-to-use instrumentation that extends reliable environmental monitoring to community stakeholders and educators. Dissolved gas measurements can offer a holistic insight into the biogeochemical processes occurring in a water mass. A novel, low-cost (<$1000) dissolved gas sensor suite which integrates carbon dioxide, oxygen, and total dissolved gas pressure measurements into one compact instrument suite has recently been developed for use in an underway flow-through system. Here we present results from a deployment of this sensor suite from a month-long cruise across the Subpolar North Atlantic. This prototype multi-gas sensor was evaluated against commercial-grade oceanographic instrumentation (shipboard underway pCO₂, Aanderaa dissolved oxygen optode) along with discrete dissolved Ar, O₂, and N₂ samples to demonstrate its field performance. The prototype’s measurements correlated strongly with commercial instrumentation on sub-hourly timescales and continued to perform well even in regions of high variability (e.g., crossing frontal transitions between water masses with very different compositions). The low cost of this sensor suite creates an opportunity for wide spatiotemporal coverage both by supplementing existing monitoring systems and in the deployment of future arrays. In addition, low cost sensor suites will allow access to a more global group of scientists. These promising results indicate that the sensor may be suitable even in dynamic areas, such as coastal and estuarine regions, which are especially vulnerable to anthropogenic impacts and uniquely interwoven with human life.