shelf seas. Figures 3 and 4 show the changes in salinity and oxygen in the DSOW density range from Fram Strait past the Barents, Kara, and Laptev seas. Subhalocline waters with σ0, 27.9 to 28.02 to are freshened somewhat passing the Barents Sea and substantially so after passing the Kara Sea. Along the entire Eurasian Basin boundary all waters withσ0, < 27.9 are much fresher than the inflowing waters.
Off the Barents shelf subhalocline oxygen concentrations for water withσ0, < 27.98 are much greater than in the inflowing water. Oxygen concentrations in this density range off the Kara and Laptev seas are significantly lower than those off the Barents shelf, indicating that for this density range the Fram Strait inflow and the Barents Sea are the primary ventilators. The peak in dissolved oxygen nearσ0 = 28.O2 in Fram Strait is derived from the Greenland Sea. It is clearly evident at 31° E and to a lesser degree at 91°E and 131°E, showing that at this density the Greenland Sea may be a significant ventilator of the Arctic Ocean.
The Barents Sea has long been recognized as a potential source of dense waters. A narrow tongue of salty bottom water is sometimes seen in the northern Norwegian Sea. Bottom waters in the Barents Sea (e.g., cf. Swift et al., 1983) cover a wide T/S range, with geographic variations that reflect the salinity of the overlying water. Dense bottom waters resulting from brine rejection are also observed near locations of wintertime polynas. But in the Arctic Ocean the waters immediately adjacent to the Barents Sea - assumed to be largely from the Barents Sea - are cold and fresh compared to the basin interior waters, and are very high in oxygen concentration and relatively low in nutrients. This water brings about significant modification of the Arctic Ocean interior.
There has been recent focus on the Kara Sea in regard to ventilation of the Arctic Ocean interior, but the Barents Sea appears to be a stronger contender. The proximity to the Atlantic water source, the relatively low river inflow to the Barents Sea, and the presence of winter polynas provide an environment fostering production of dense shelf waters. These have a low, Atlantic-like silicate concentration, and concentrations of tracers associated with river input should also be relatively low. These signais may provide means to trace dense contributions to the Arctic basins from the Bareis Sea.
Waters in the DSOW density range in the Canadian Basin are modified by dense waters from the Chukchi sea and by dense inflows originally from the Eurasian shelf seas. The primary local shelf source appears to be the Chukchi Sea, a region fed by silica-rich low
