Wave Glider-Based Measurements and Corrections of Near-Surface pCO2 Gradients in the Coastal Ocean

Carbonate system dynamics are highly variable in coastal and shelf regions, and poor spatiotemporal measurement resolution leads to inadequate constraints for global carbon sequestration estimates. Additionally, conventional pCO₂ measurement-based flux calculations require an assumption of homogeneity in near-surface waters, excluding effects such as biological drivers and air-sea disequilibrium. To quantify the effect of these drivers by capturing high resolution measurements during short-term events, we present the deployment of a Liquid Robotics Wave Glider equipped with mirrored gas sensor suites at the surface and sub-surface during the 2022 spring bloom on the Scotian Shelf in eastern Canada. The temporal variability in the data reveals biologically driven diurnal pCO₂ behavior that conventional low-resolution methods may overlook. Additionally, through direct measurement of surface and sub-surface pCO₂ levels, we demonstrate that conventional underway measurement methods systematically underestimate surface pCO₂ values in this region by 1–10 μatm, leading to flux estimation errors of up to 7%. These findings emphasize the value of high-resolution data for determining drivers of spatial variability and question the capacity of underway lines to measure true surface pCO₂ values. By employing vehicle-based measurement techniques, we can improve our understanding of carbon dynamics in coastal environments and refine flux estimates for accurate climate modeling and management strategies.