1994 Arctic Ocean Section
Basin and in the Amundsen Basin. In the Nansen Basin the "excess" total alka-
linity was much reduced or not present, indicating that most of the near-
surface fresh water in these regions of the AOS-94 path comes from melting
sea ice.
High values of total carbonate were also observed near the surface. These
correspond to the total alkalinity maximum and are consistent with dissolved
calcium carbonate being brought into the Arctic Ocean by river runoff. There
are also high total carbonate values in the halocline (depth about 100 m) of
the Canada Basin that correspond closely with the nutrient maximum, consis-
tent with the "excess" total carbonate being regenerated along with nutrients
during the decay of biogenic matter. These high values were not present after
Station 14, where the nutrient maximum also disappeared. The total carbon-
ate in the near-surface water and in the halocline can be used to assess the
amounts of carbon entering the Arctic Ocean from the Siberian tundra (river
runoff ) and the amount entering as a result of carbon fixation on the contin-
ental shelves.
Profiles of both total alkalinity and total carbonate show small variations in
deeper water that are greater than the precision of these measurements. These
structures may be interpretable in terms of the water masses present and
processes such as the sequestering of anthropogenic carbon dioxide, but any
definitive interpretation will have to await more detailed data analysis, not to
mention inspired thought.
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