Using the nutrient ratio NO/PO as a tracer of continental shelf waters in the central Arctic Ocean

Cara Wilson and Doug W. R. Wallace

Journal of Geophysical Research 95: 22,193-22,208, 1990.

Abstract

Historical nitrate, phosphate, and dissolved oxygen data from the central Arctic Ocean are examined with particular emphasis on the conservative parameters NO (9*NO3 + O2) and PO (135*PO4 + O2). The NO/PO ratio is shown to be increase with depth in the Canada Basin, being ~0.78 in Surface and Upper Halocline Waters and ~1.0 in the Atlantic Layer and Deep Waters. Lower Halocline Water is marked by NO and PO minima and intermediate NO/PO. NO/PO rations from the Arctic shelf seas are examined to determine possible source regions for the various water masses. The NO/PO ratio of Canada Basin Deep Water implies an upper bound of 11% shelf water contribution to this water mass. A slight oxygen maximum core in the Lower Halocline Water is identified at a salinity of S=34.5 in the vicinity of the Alpha Ridge. This core appears to be diminished by diapycnal mixing and does not extend into the Beaufort Gyre.

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