Critical uncoupling between biogeochemical stocks and rates in Ross Sea springtime production-export dynamics

Abstract. Biogeochemical glider surveys in the Ross Sea between 2010 and 2023 were combined and analysed to assess production-export stock and rate dynamics. As the most productive of any Antarctic continental shelf, the Ross Sea is a site of substantial physical and biogeochemical interest. While this region and its annual bloom have been characterised for decades, logistical constraints, such as ship time and sea ice cover, have prevented a comprehensive understanding of this region over long (>1–2 months) time scales and in high spatiotemporal resolution. Here we use high-resolution data sets from autonomous gliders in mass balance equations to calculate short-term net community production via oxygen concentrations, change in POC concentrations over time, and POC export potential during the period of peak primary production in the region. Our results show an overall decoupling of net community production from biomass concentrations and changes in carbon over time. NCP and carbon change vary between seasons and appear related to changes in ice concentration and stratification. Substantial variability exists in all datasets, but high-resolution sampling reveals short term variations that are likely masked in other studies. Our study reinforces the need for high-resolution sampling and supports previous classifications of the Ross as a high productivity (average NCP range -0.7–0.2 g C m^-2 d^-1), low export (average changes in POC over time range -0.1–0.1 g C m^-2 d^-1) system during the productive austral spring and sheds additional light on the mechanisms controlling these processes.