Table_1_Effects of the glacial meltwater supply on carbonate chemistry in Bowdoin Fjord, Northwestern Greenland.docx

To understand the effects of the glacial meltwater supply on carbonate chemistry and the air–sea CO₂ flux within the fjord, water samples were collected in Bowdoin Fjord in northwestern Greenland for dissolved inorganic carbon (DIC) concentration, total alkalinity (TA), oxygen isotopic ratio (δ¹⁸O), and chlorophyll a concentration analyses in the summers of 2016 and 2017. The partial pressure of CO₂ (pCO₂) in surface water, calculated from DIC and TA, was less than 200 µatm, and was significantly lower than that in the atmosphere (399 ± 3 µatm). Therefore, surface water of the fjord acts as sink for CO₂ in the atmosphere (–4.9 ± 0.7 mmol m^–2 d^–1). To evaluate the effects of freshwater and land-derived substances by glacial meltwater on pCO₂ in the fjord, we calculated the changes of pCO₂ in salinity and carbonate chemistry that would result from the inflow of glacial meltwater into the fjord. The calculated pCO₂ was high near the calving front, where the contribution of glacier meltwater was significant. Examination of the relationship between salinity-normalized DIC and TA, which was considered DIC and TA input from the land, suggested that the land-derived high pCO₂ freshwater affected mainly by the remineralization of the organic matter by bacterial activity was supplied to the Bowdoin Fjord.