Modelling the advection of pollutants in the Hudson Bay complex

The Hudson Bay Complex is a system of semi-enclosed waterbodies in the eastern Canadian sub-Arctic with limited communication to the Arctic Ocean via Fury and Hecla Strait, and to the North Atlantic Ocean via Hudson Strait. There has been a significant increase in ship traffic in the Hudson Bay Complex as it provides a maritime link to Eurasia, known as the Arctic Bridge, and the southern route of the Northwest Passage, connecting the ports in the North Atlantic Ocean and Pacific Ocean. The increasing ship traffic could promote a higher risk of accident, especially when considering the higher mobility of sea ice due to the warming over the polar region. In this study, we used a high-resolution numerical model to highlight the circulation pathways of pollutants due to ocean advection. We released Lagrangian particles at 9 sites, located along the Arctic Bridge and the southern Northwest Passage, every 10 days through the operating season (June–October) for 12 years (2004–2015), to determine when and over which sites the accidental spill of pollutant would have the greatest negative impact. We characterized three circulation pathways with respect to the oceanic circulation regime of where the particles were initially seeded, and computed the following parameters to numerically describe the spreading of particles: area occupied, distance travelled, and the depths of particles. We conclude that the particles released in eastern Hudson Strait exhibited the largest spreading area rapidly below the surface layer, posing a challenge for recovery operations and a threat to the environment.