Carbon cycling in the coastal Arctic of Canada

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Because the world's oceans are the largest of the planet's carbon sinks, offsetting around 30% of present anthropogenic emissions, it is especially important that we understand important features of the marine carbon cycle and that these features are soundly represented in general circulation models. A critical gap in our understanding of the system's CO2 source/sink dynamics relates to the role played by sea ice. The traditional assumption adopted for both models and polar marine CO2 flux studies is for sea ice to exist as an impermeable layer, preventing air-sea exchange. Research in the last decade has shown sea ice to be an active participant in the marine carbon cycle, exchanging CO2 between both the ocean and atmosphere, and hence the assumption that sea ice is a passive participant in the polar marine carbon cycle is incorrect. Despite advancements in our understanding of the sea ice carbonate system, we still do not know exactly how sea ice influences air-sea CO2 exchange, and by extension, the net effect of sea ice on a region's carbon budget. The over-arching objective of my proposed research is to understand the implications of sea ice and sea ice loss on the upper (atmospheric) limb of the Arctic marine carbon budget. Imbedded are the sub-objectives to develop parameterizations for both the air-ice-ocean transport of inorganic carbon and for air-sea exchange of CO2 in mixed-ice ocean environments. Proposed methods involve a mix of field expeditions and ice tank experiments. Field projects will be both ship- and ice-camp based, and will involve the direct measurement of the CO2 flux using eddy covariance systems, in conjunction with the measurement of surface microclimate, and CO2 system components of sea ice and the water column.