We investigated the relative contributions of various factors that influence seasonal changes in sea surface partial pressure of \(\hbox {CO}_{2}\) ( \(\hbox {pCO}_{2}\) , calculated from the measured pH and total alkalinity) in four regions of northwestern Greenland: Nares Strait, Lincoln Sea, Sherard Osborn and Petermann fjords. Using the temperature minimum layer as a proxy for winter conditions, we examined \(\hbox {pCO}_{2}\) dynamics from the onset of sea-ice melt to summer. Our findings revealed significant spatial variability in \(\hbox {pCO}_{2}\) , driven by differences in temperature, freshwater inputs, and biological activity. In particular, in Sherard Osborn Fjord substantial freshwater inputs and strong stratification were found to enhance \(\hbox {pCO}_{2}\) accumulation, while in Petermann Fjord biological \(\hbox {CO}_{2}\) uptake was the main driver. This study, conducted in summer 2019, underscores the critical role of northwest Greenland’s coastal waters as a summer \(\hbox {CO}_{2}\) sink. It highlights the complex interplay of physical and biogeochemical processes in modulating \(\hbox {pCO}_{2}\) , suggesting significant regional differences in \(\hbox {CO}_{2}\) dynamics between two neighboring fjords.
