The Arctic Ocean is one of the most climate responsive regions of the globe. Small changes in temperature can cause large changes in the Arctic marine environment. Yet, we still have a novice understanding of Arctic oceanography. Inputs, outputs, and internal processes all require continued research to predict how changes in the Arctic will influence the globe.
The Arctic Ocean is a semi-enclosed basin, with seawater entering through constrained regions such as the Bering Strait between Alaska and Russia and the Fram Strait near the northeast corner of Greenland (check out the figure below, xxxx COLOR arrows indicate seawater flowing into the Arctic Ocean. Seawater leaving the Arctic have several flow paths (xxx color in fig) that ultimately enter the North Atlantic. It’s this connection to the North Atlantic that gives the Arctic Ocean a critical role in global climate. Waters exiting the Arctic play a role in deep water formation and, in terms of climate, deep water formation is critically important in setting ocean’s carbon and heat budgets.
One way the Arctic can influence the North Atlantic is via freshwater exports. The Arctic receives freshwater inputs from rivers (10% of the world’s river discharge), sea ice melt, and from Pacific-derived seawater (salinity = 32.5 and is more fresh relative to the Atlantic where salinity = 34.9). The Arctic Ocean retains a substantial portion of this freshwater, but also exports much of this fresh water to the North Atlantic (this export and storage can depend on atmospheric conditions).
In researching the Arctic, I have three driving questions:
- Where are Pacific-derived waters observed in the basins and how much is there?
- What rivers contribute to the riverine component observed in the central Arctic and by how much?
- How do interactions with broad continental shelves influence the central basin?
The first two questions play into the freshwater budget explained above. The Arctic ocean stores and exports freshwater, we can quantify how much freshwater is being exported or stored, but we don’t have a thorough quantitative grasp on the contributions from each source. This is particularly important as the Arctic is impacted by climate. It is likely we will see increasing contribution of freshwater from glacially fed rivers and sea ice melt; but do we expect the contribution from Pacific waters to remain the same?
The third question is particularly important as there has been an increasing understanding that, globally, the continental margins may contribute substantially to the basin geochemistry. The Arctic Ocean is a great area to study this because the shelf:basin area is 1:1, which is very large. In a semi-enclosed basin like the Arctic, we would expect to observe the influence of the shelf if the margins are influencing basin geochemistry.
The Arctic Ocean, more than retaining seawater from and and exporting to the Pacific and Atlantic, receives 10% of the worlds river discharge. This and the reagional bathymetry and topography lead to a highly fresh surface layer when compared to other ocean.
Monitoring these in Pacific waters entering the Arctic and a fraction of Atlantic waters spend a significant amount of time over the wide continental shelves before entering the Arctic Basins.
My research focuses on four tracers: gallium, barium, vanadium, and methane.
Each tracer provides unique insight into the question of how oceanic margins influence the central ocean and whether or not shelf-imparted features are evident in waters leaving the Arctic.