Predicting future conditions of the Arctic Ocean system requires scientific knowledge of its present status as well as a process-based understanding of the mechanisms of change. This research effort will synthesize a number of recent, upcoming, and historical datasets to create three regional carbon budgets for the Chukchi/western Beaufort Sea, the Bering Sea, and the northern Gulf of Alaska. As waters from the North Pacific make their way through these regions a number of transformations occur that modify them before they enter the central Arctic Ocean. In general, the waters exiting these shelf seas are fresher, colder, and have lower pH due to the uptake of CO2 and the remineralization of organic matter. Because of the importance that biogeochemical transformations have in preconditioning the waters of the central Arctic and ultimately parts of the North Atlantic it is important to gain a better understanding of how these processes impact the carbon biogeochemistry of the region. The investigators propose to address this issue by better constraining the carbon budgets for three zones in the Pacific sector of the Arctic Ocean including coastal fluxes, rates of primary production and air-sea exchange of CO2 as well as developing algorithms with predictive capabilities for carbonate mineral saturation states. The aim of this effort is to determine how physical forcing and biological responses control the marine carbon cycle including the rates of air-sea CO2 exchange and net community production as well as ocean acidification effects in the contrasting shelf environments, and to better constrain the present stocks and fluxes of carbon and determine how climate change will affect the regional carbon cycle. The project will support four early career investigators, a postdoctoral scientist, and a Ph.D. student.