Dynamic ice–ocean pathways along the Transpolar Drift amplify the dispersal of Siberian matter

The Transpolar Drift (TPD) plays a crucial role in regulating Arctic climate and
ecosystems by transporting fresh water and key substances, such as terrestrial
nutrients and pollutants, from the Siberian Shelf across the Arctic Ocean to the
North Atlantic. However, year-round observations of the TPD remain scarce,
creating significant knowledge gaps regarding the influence of sea ice drift and
ocean surface circulation on the transport pathways of Siberian fresh water
and associated matter. Using geochemical provenance tracer data collected
over a complete seasonal cycle, our study reveals substantial spatiotemporal
variability in the dispersal pathways of Siberian matter along the TPD. This
variability reflects dynamic shifts in contributions of individual Siberian rivers
as they integrate into a large-scale current system, followed by their rapid and
extensive redistribution through a combination of seasonal ice–ocean
exchanges and divergent ice drift. These findings emphasize the complexity of
Arctic ice–ocean transport pathways and highlight the challenges of forecasting their dynamics in light of anticipated changes in sea ice extent, river
discharge, and surface circulation patterns.