The distribution of nutrients in the southeastern Beaufort Sea: Implications for water circulation and primary production

Publisher Website
Google Scholar
Abstract
Hydrographic data collected above the shelf and slope in the southeastern Beaufort Sea show marked contrast in surface properties of nutrients, temperature, salinity and oxygen between August 1974, a year when ice remained close to shore, and August 1975, a year with much open water. The near‐surface properties are dominated by river inputs, biological activity, and the ice regime. Below the winter mixed zone (40–50 m), properties are similar to those observed elsewhere in the Arctic Ocean. Bering sea water is detected at 50–60 m as a very weak signal in temperature, nutrients and oxygen. Upwelling in both years was observed at the eastern side of Mackenzie Canyon; this upwelling likely results from the interaction of coastal circulation with topography. Estimates of new productivity based on nutrient budgets are low (20 g C m−2 yr−1) compared to temperate coastal waters, but fall in the range expected for the Arctic. In 1974, the heavy ice year, turbid water and ice cover appear to have reduced new production by about 30%. Calculations show that this production over the shelf could potentially supply a significant portion of the nutrients found in the upper halocline over a wide region of the Arctic Ocean by regeneration at the shelf bottom and transport off the shelf in brine drainage.