Victoria Williams, University of Richmond

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Ocean acidification disrupts the carbonate chemistry of marine ecosystems and threatens calcifying organisms, which then harms coastal communities that depend on them. There is a lack of understanding of the effects of ocean acidification in estuaries due to their complexity and the minimal spatial and temporal monitoring being conducted. Because high-quality commercial CO₂ sensors are very expensive, monitoring at greater frequencies is a costly and difficult task that is never accomplished. Acknowledging the need to understand the carbonate chemistry, the objective of this project was to design and build a deployable autonomous CO₂sensor (DACS) at a price of under a thousand dollars. The study consisted of the construction of a DACS followed by verification of the product through field testing and laboratory analysis. The laboratory analysis consisted of a collection of water samples and measurement of total alkalinity and dissolved oxygen to calculate pCO₂. The construction of the DACS was a success after several design iterations. The DACS CO₂ measurements were verified with the laboratory results. While the DACS and laboratory monitoring of Horn Point Laboratory (HLP) hatchery water data exhibited similar trends, results somewhat diverged indicating the need for further development of the DACS to improve accuracy. Despite inaccuracy, optimizing and verifying the DACS performance will continue, as development of an inexpensive and reliable CO₂ sensor is imperative for future ocean acidification research.