Wood, M., Carroll, D., Fenty, I.G., Bertin, C., Darby, B., Dutkiewicz, S., Hopwood, M.J., Khazendar, A., Meire, L., Oliver, H., Parker, T., and Willis, J.K. (2025)
Presented at:
AGU Annual Meeting 2025Over the past several decades, increasing Arctic air temperatures have caused extensive melt on the surface of the Greenland Ice Sheet. Unlike terrestrial runoff, surface ice-sheet melt drains through glacier cracks and crevasses and is often discharged several hundred meters below the ocean surface at glacier outlets. The emergence of this fresh, buoyant subglacial discharge at the grounding line generates turbulent upwelling plumes. Recent evidence has shown that, similar to other upwelling regions, Greenland's plumes upwell substantial nutrient fluxes from depth, contributing to enhanced productivity within fjords and on the shelf. Here we use the ECCO-Darwin ocean biogeochemistry model combined with a downscaled-model approach to investigate plume-driven upwelling from Sermeq Kujalleq — one of the most active glaciers in Greenland. We test the sensitivity of ice-sheet melt and associated upwelling on nutrient availability and productivity by comparing simulations with and without subglacial discharge in years of high/low melt. We find that the upwelling plume at Sermeq Kujalleq substantially increases nutrient concentrations in the photic zone, increasing primary productivity by 15-40% inside Disko Bay and further offshore on the shelf. Despite this increase in productivity, however, annual carbon dioxide uptake rises by only ~3% due to reduced solubility in plume-upwelled waters. These findings suggest that intensifying ice sheet melt may alter Greenland’s coastal productivity and carbon cycling under future climate scenarios.
