Insights on Cross Shelf Transport in the Arctic Derived from Barium Distributions
Kelly K. Falkner
Oregon State University Oceanography Dept.
Ocean Admin Bldg. 104 Cornvallis, Oregon 97331-5503 U.S.A.
Tel: 1-541-737-3625
Fax: 1-541-737-2064
kfalkner@oce.orst.edu
Beginning in 1992, seawater samples collected from a variety of platforms throughout the Arctic have been analyzed for their dissolved Ba content via high precision (2 percent ID-ICPMS. From the data set to date, it can be concluded that the Mackenzie River is at least 4-fold enriched in Ba over other major rivers emptying into the Arctic. This causes markedly elevated Ba contents in surface waters of the Beaufort gyre region. Barium distributions do not support the circulation of Mackenzie influenced waters over the Chukchi shelf that has been indicated by high resolution model river "dyer" experiments.
While their Ba contents are less than the Mackenzie, Eurasian rivers are enriched with respect to the shelf seawaters into which they enter. Our data suggest that in 1993-94 the predominant pathway of Siberian river waters was along shelf toward the East Siberian Sea with entrance into the interior in the vicinity of the Mendeleev Ridge. In 1995, there circulation appeared to switch whereby river influenced waters tended closer to their shelf region of origin with cross shelf transport occurring along the Lomonosov Ridge. This is in accord with changes in the positioning of the transpolar drift indicated by the ice buoy program. The lesser dilution of interior waters brought about by the along shelf pathway my possibly explain of halocline waters observed in the interior Nansen and Makarov basins during the 1993-95 period.
