Gateway to the High Arctic: The Importance of Ocean Connectivity

“Borealization” of the Arctic

The flows of Atlantic water across the Greenland-Scotland Ridge and Pacific water through the Bering Strait act as conveyors for carrying heat northward into the Arctic and drive the “borealization” of the Arctic. Simultaneously, melting Arctic ice sends freshwater southward, altering subarctic currents and impacting weather patterns and ecosystems across the Subpolar North Atlantic and beyond. Monitoring these currents is crucial for understanding the broader impacts of global warming on e.g. biodiversity and provision of ecosystem services.

The subarctic regions can be considered the oceanographic gateway to the High Arctic. Monitoring pollutant transport, invasive species and biodiversity is essential to better understanding the marine environment in the Arctic region and how it is affected by the “borealization”.

Changes in the “Gulf Stream”

The Atlantic Meridional Overturning Circulation (AMOC), is a main engine inducing oceanic connectivity between the Arctic and lower latitudes. Warm, saline water flows northward on the surface, while cold, oxygen-rich water returns southward in the depths. It plays a crucial role in the rapidly changing Arctic Ocean, subpolar ocean conditions and global ocean circulation. Changes in the AMOC could therefore have profound implications. If heat transports increase, this would further reduce Arctic sea ice, altering habitats for species like copepods, which are critical to the food web. Similarly, shifts in surface waters could drive marine species, including fish, toward the poles, disrupting ecosystems and fisheries.

While the Intergovernmental Panel on Climate Change (IPCC) predicts a weakened AMOC in the next century, recent studies suggest increased oceanic heat transport to the High Arctic. Either way, these changes will profoundly affect marine biodiversity, biogeochemical cycles and climate feedback mechanisms.

Zonal Connectivity

The horizontal, or zonal, connections, driven by large oceanic gyres, are equally important. The atmospheric jet stream drives storm systems and oceanic currents in the subpolar Atlantic, which in turn impact nutrient upwelling and circulation patterns. These movements influence the temperature, salinity and thereby biodiversity of Atlantic waters flowing polewards.

Fish, marine mammals and seabirds are also affected by these currents, with some species migrating horizontally along these oceanic pathways. Understanding these east-west connections in the subpolar region, including convection and water mass mixing processes and their impact on ecosystems, is critical for effective conservation and ecosystem management.

Enhancing Arctic Observations for a More Predictable Future

To address the challenges of climate change and ensure sustainable management of Arctic and subarctic resources, a robust observational framework is essential. Although existing international and regional observation and monitoring programs cover portions of the subarctic, the Arctic Council could coordinate efforts to better understand how key variables such as ocean temperature, salinity and plankton dynamics interact with fish stocks, seabirds and marine mammals across the circumpolar North.

Enhanced monitoring of the air-sea interface, where atmospheric and oceanic processes converge, would improve weather forecasting and help anticipate future changes. This is critical in a warming world where weather patterns are becoming increasingly variable and extreme.

Prioritizing observations in key regions of the subarctic marine environment is essential for strengthening predictive modelling, advancing comprehensive marine ecosystem-based management and addressing critical challenges such as the transport of marine pollutants and plastics, and shifts in marine biodiversity.