New paper in GRL: the local biogeochemical impacts of Greenland subglacial discharge

Much of Greenland runoff is delivered to the coastal ocean at marine-terminating glaciers, potentially hundreds of meters below the sea surface. The resulting turbulent buoyant plumes can entrain nurtrient-rich deeper waters, potentially delivering these nutrients to the upper water column which can support elevated primary productivity. The importance of this buoyant plume-productivity effect around Greenland is not yet clear, however.

Here, we apply buoyant plume theory on a pan-Greenland scale to assess the potential for subglacial-discharge driven nutrient enhancements between glacier termini, and find that most of the upwelling is concentrated in a few hotspots, with 14% of glaciers driving >50% of the total nitrate effect. We then compare the model results to coastal chlorphyll concentrations, and find strong interannual relationships are limited to CW and NW Greenland. Subglacial discharge fluxes can explain most of the interannual variability in seasonal chlorophyll in northern Disko Bay and Uummannaq Fjord, which host Greenland’s largest commercial fisheries.

Oliver, H., Slater, D., Carroll, D., Wood, M., Morlighem, M., & Hopwood, M. J. (2023). Greenland subglacial discharge as a driver of hotspots of increasing coastal chlorophyll since the early 2000s. Geophysical Research Letters, 50, e2022GL102689. https://doi.org/10.1029/2022GL102689