The role of Irminger Rings for biogeochemical tracer advection in the Labrador Sea.

The Labrador Sea is one of two major sites of the subpolar North Atlantic where deep convection occurs in wintertime as the ambient stratification is weakened through surface cooling and the water column homogenized to up to 2000 m depth. Deep convection has important biogeochemical implications, for example, the ventilation of the deep ocean through the formation of Labrador Sea Water, when convective mixing brings deep-water, undersaturated in oxygen, in contact with the atmosphere. Oceanic eddies in the Labrador Sea, in particular Irminger Rings, are known to transport heat and freshwater from the boundary current towards the central basin. This process regulates the strength of convection by influencing the preconditioning and restratification processes, hence modulating the production of Labrador Sea Water. However, the impact of these eddies on lateral biogeochemical fluxes between the coastal and open Labrador Sea, including the regions where deep convection is most pronounced, remains elusive. In this study, a high-resolution (1/12°) coupled biogeochemical-physical model of the northwest North Atlantic is employed to investigate the role of these eddies for lateral transport of biogeochemical constituents in the three distinct regions: eastern and western boundary and the central Labrador Sea. Oxygen, nutrient, and carbon budgets for these regions will be presented with an emphasis on horizontal and vertical transports, and mean and eddy-driven advection. The results of the biogeochemical budgets will be compared with those from the heat and freshwater budgets.