Autonomous Observation of Seasonal Carbonate Chemistry Dynamics in the Mid-Atlantic Bight

Ocean acidification alters the oceanic carbonate system, increasing potential for ecological, economic, and cultural losses. Historically, productive coastal oceans lack vertically resolved high-resolution carbonate system measurements on time scales relevant to organism ecology and life history. The recent development of a deep ion-sensitive field-effect transistor (ISFET)-based pH sensor system integrated into a Slocum glider has provided a platform for achieving high-resolution carbonate system profiles. From May 2018 to November 2019, seasonal deployments of the pH glider were conducted in the central Mid-Atlantic Bight. Simultaneous measurements from the glider's pH and salinity sensors enabled the derivation of total alkalinity and calculation of other carbonate system parameters including aragonite saturation state. Carbonate system parameters were then mapped against other variables, such as temperature, dissolved oxygen, and chlorophyll, over space and time. The seasonal dynamics of carbonate chemistry presented here provide a baseline to begin identifying drivers of acidification in this vital economic zone.