The physico-chemical effects of sea ice on water-ice-air gas transfer

[[2008gl036318]] During seawater freezing dissolved solutes (ions and gases) are segregated from the ice crystal structure, producing a cascade of processes within sea ice and at the ice water interface. Over the seasonal cycle these processes can produce a net redistribution of gases from the surface ocean.

brine_drain_surfocean_webAs gases become supersaturated in the water beneath growing sea ice, bubbles nucleate and become included in the ice along crystal boundaries.  Within brine (hypersaline liquid found inside sea ice), the precipitation of calcite complexes leads to high pCO2 and this gas can diffuse to the atmosphere, depending on the gas and liquid filled porosity of the ice. As a substrate for growth, sea ice can provide stable (albeit low) light conditions for phytoplankton growth.

This work has attempted to isolate the physical processes, such as solute segregation and air-sea gas transfer from the biogeochemical processes, by measuring the time evolution of inert gases under the influence of ice formation, deformation and melt, in the laboratory. Some of these results are in press now