Quanitative considerations of dissolved barium as a tracer in the Arctic Ocean

Dissolved barium (Ba) was measured along transects across Fram and DenmarkStraits as part of the 1998 ARK-XIV/2 Polarstern expedition. Results are combined withother available tracer observations to analyze water mass composition at Fram Strait. Acombination of Pacific water and Eurasian river runoff dominated (>80% and >10% of thetotal mass, respectively) the upper East Greenland Current (EGC), while the remainder ofthe section was dominated by North Atlantic water. A much smaller contribution of Pacificwater to the EGC (50%) at Fram Strait in 1987 suggests that this component can be quitevariable in time. North American river water was not detectable at Fram Strait in 1998.Presumably, the Eurasian river water we observed at Fram Strait transited eastward alongshelf within the Arctic, mixed with Pacific water in the vicinity of the East Siberian Sea, andwas borne by the transpolar drift across the Arctic Ocean. In the absence of significant netice formation along the way such a pathway can be expected to produce more pronouncedfreshening of the EGC than when Eurasian river water mixes more directly off shelf intosalty Atlantic waters and Pacific water is diverted largely through the Canadian archipelago.Existing measurements at the main Arctic gateways were used to construct a Ba budget forthe Arctic Ocean under conditions of simultaneous mass, heat, and salt conservation. Thispreliminary budget is statistically consistent with the steady state hypothesis. On the Arcticbasin scale, Ba appears to be conservative