Sea-surface CO2 fugacity in the subpolar North Atlantic

We present the first year-long subpolar trans-Atlantic set of surface seawater CO2 fugacity (fCO(2)(sw)) data. The data were obtained aboard the MV Nuka Arctica in 2005 and provide a quasi-continuous picture of the fCO(2)(sw) variability between Denmark and Greenland. Complementary real-time high-resolution data of surface chlorophyll-a (chl-a) concentrations and mixed layer depth (MLD) estimates have been collocated with the fCO(2)(sw) data. Off-shelf fCO(2)(sw) data exhibit a pronounced seasonal cycle. In winter, surface waters are saturated to slightly supersaturated over a wide range of temperatures. Through spring and summer, fCO(2)(sw) decreases by approximately 60 mu atm, due to biological carbon consumption, which is not fully counteracted by the fCO(2)(sw) increase due to summer warming. The changes are synchronous with changes in chl-a concentrations and MLD, both of which are exponentially correlated with fCO(2)(sw) in off-shelf regions.