Surface Water pCO2 Variations and Sea-Air CO2 Fluxes During Summer in the Eastern Canadian Arctic

Based on a 2 year data set, the eastern Canadian Arctic Archipelago and Baffin Bay appear to be a modest summertime sink of atmospheric CO2. We measured surface water CO2 partial pressure (pCO(2)), salinity, and temperature throughout northern Baffin Bay, Nares Strait, and Lancaster Sound from the CCGS Amundsen during its 2013 and 2014 summer cruises. Surface water pCO(2) displayed considerable variability (144-364 mu atm) but never exceeded atmospheric concentrations, and average calculated CO2 fluxes in 2013 and 2014 were -12 and -3 mmol C m(-2) d(-1) (into the ocean), respectively. Ancillary measurements of chlorophyll a reveal low summertime productivity in surface waters. Based on total alkalinity and stable oxygen isotopes (delta O-18) data, a strong riverine signal in northern Nares Strait coincided with relatively high surface pCO(2), whereas areas of sea-ice melt occur with low surface pCO(2). Further assessments, extending the seasonal observation period, are needed to properly constrain both seasonal and annual CO2 fluxes in this region.