Ocean turbulent dissipation rates in the fjords around Uummannaq, Northwest Greenland, derived from a vertical microstructure profiler equipped with shear probes in summer 2022

Glacial fjords represent critical ecosystems in high-latitude regions, their productivity heavily influenced by nutrient dynamics, as nutrient availability, particularly in nutrient-poor environments, is one critical factor limiting primary productivity. With glaciers retreating under a warming climate, these dynamics might change dramatically, as subglacial discharge plumes - known to entrain nutrient-rich deep water, enhancing surface productivity - disappear. However, there are other processes to transport nutrients to the surface layers, and the full extent of nutrient transport mechanisms remains inadequately understood. In a study conducted in a northwest Greenland fjord system, we focused on measuring vertical mixing, a key factor to calculate vertical nutrient fluxes. Vertical profiles of turbulent microstructure were obtained with a stand-alone VMP250, Rockland Scientific Inc.. These data can be used to investigate the spatio-temporal variability of vertical mixing in the fjord system, to derive vertical diffusivities and calculate tracer fluxes, e.g., heat and nutrients. Our findings contribute crucial insights into the vertical transport dynamics in Greenlandic fjords, enhancing predictive capabilities regarding ecosystem shifts linked to glacier retreat.