The Three Rs: Resolving Respiration Robotically in Shelf Seas

Ocean deoxygenation threatens ocean productivity, carbon cycling and marine ecosystems. Shelf seas are highly dynamic regions, which contributes to their high productivity and also makes monitoring and constraining their oxygen status a challenge. Here, using the temperate Celtic shelf sea (April and July 2015) as a case study, we present high-resolution ocean glider observations of turbulence and biogeochemical parameters, demonstrating the potential of these autonomous platforms for environmental monitoring. We estimate vertical turbulent oxygen fluxes be 25% higher in summer than in spring, due to the presence of subsurface chlorophyll and associated oxygen maxima at the seasonal thermocline. We demonstrate that glider-based estimates were able to constrain similar bottom layer respiration rates as those derived from traditional ship-based measurements. We suggest ocean gliders are useful monitoring tools that can aid sustainable management of shelf sea ecosystems.