A Blue Arctic – ice melt and freshwater in the Barents Sea

Summary

The Arctic is warming as four times faster than the global average with rapid loss of ice and major shifts in the distribution of freshwater. This PhD will quantify the freshwater content of the Barents Sea and impacts on ocean processes.

Project Background

As the Arctic warms it is shifting from being a white ocean (ice-covered) to blue ocean (open water). The freshwater associated with this enhanced melt is a key component of Arctic oceanography. The volume of freshwater and its distribution establishes the fundamental structure and dynamics of the Arctic Ocean and the adjacent seas. This structure manifests itself as vertical and lateral gradients in ocean salinity (saltiness) and density, which can have controlling effects on the movement and transfer of heat, nutrients and particulates. However, the Arctic is warming quickly and with that comes enhanced melt from land-based glaciers and sea ice. More freshwater is being put into the Arctic system changing the vertical structure and horizontal gradients. One region that has experienced rapid reduction in sea ice is the economically important Barents Sea, north of Norway. This is a shallow, productive sea with a strong inflow of warm water from the Atlantic to the south, and export of ice and polar waters from the Arctic to the north. Previous studies have shown fundamental shifts in the distribution of freshwater on seasonal and interannual timescales.

The PhD project will quantify the freshwater content of the Barents Sea using a tracer technique that utilises oxygen isotopes. Through a combination of salinity and isotope values it will be possible to identify the source, the vertical distribution and seasonal variations in freshwater content in different regions of the Barents Sea. By combining this knowledge with data on sea ice distribution, profiles of ocean salinity and regional numerical models, the project will investigate the impact of sea ice loss in the Barents Sea on the water column structure. These changes in the structure of the Barents Sea will have consequences on the biogeochemical processes leading to potential impacts on the regional ecology and ecosystem services. The aim is to develop a more complete understanding of how the Barents Sea is evolving under a changing climate and the projected wider system impacts. 

Key Research Questions

1. What is the seasonal distribution of freshwater in the Barents Sea
2. What is the impact of freshwater on water column stability from different sources (sea ice melt and glacial melt)
3. How has the freshwater content of the Barents Sea changed on interannual timescales
4. What are the projected future impacts of enhanced freshwater on the Barents Sea system, particularly with respect to biogeochemical cycling.

Please see the full project description here: https://www.ed.ac.uk/e4-dtp/how-to-apply/supervisor-led-projects/project?item=1509