Ocean Circulation and Geochemistry
CCl4 profiles obtained at Station 19 above the Mendeleyev Ridge, where bound-
ary currents are believed strong, and at Station 29 in the central Makarov
Basin, where flows are believed to be weak, show important differences in
both the concentrations and the penetration depths of all the compounds.
This suggests that transport mechanisms are stronger around the basin's exte-
rior than at its interior and that bathymetry plays a major role in the circula-
tion of the Arctic Ocean.
Furthermore, Station 35, east of the Lomonosov Ridge in the central
Amundsen Basin, shows higher values of CFCs and CCl4 in intermediate wa-
ter layers compared to the central Makarov Basin. This suggests a closer con-
nection with laterally transported incoming source waters. In the deep waters
of the Makarov Basin, greater than 2000 m, concentrations of CFCs and CCl4
are below detection limits, indicating that these waters have a residence time
longer than a century. In the Amundsen Basin the penetration is deeper, with
CCl4 values above the detection limit to beyond 3000 m, signaling that these
waters are less isolated than those in the Makarov Basin. A mesoscale feature is
apparent from temperature and salinity measurements and is confirmed by
CFC concentrations at Station 22 between 900 and 1400 m, about 20% higher
than nearby stations. This eddy-like structure is evidence of a mechanism
whereby waters from the Siberian Shelf are transported into the interior of the
Makarov Basin.
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