The vertical distribution of nutrients and oxygen 18 in the upper Arctic Ocean

The observed vertical nutrient distribution including a maximum at about 100 m depth in the Arctic Ocean is investigated using a one-dimensional time-dependent circulation model together with a simple biological model. The circulation model includes a shelf-forced circulation. This is thought to take place in a box from which the outflow is specified regarding temperature and volume flux at different salinities. It has earlier been shown that the circulation model is able to reproduce the observed mean salinity and temperature stratification in the Arctic Ocean. Before introducing nutrients in the model a test is performed using the conservative tracer δ18 (18O/16O ratio) as one extra state variable in order to verify the circulation model. It is shown that the field measurements can be simulated. The result is, however, rather sensitive to the tracer concentration in the Bering Strait inflow. The nutrients nitrate, phosphate, and silicate are then treated by coupling a simple biological model to the circulation model. The biological model describes some overall effects of production, sinking, and decomposition of organic matter. First a standard case of the biological model is presented. This is followed by some modified cases. It is shown that the observed nutrient distribution including the maximum can be generated. The available nutrient data from the Arctic Ocean are not sufficient to decide which among the cases is the most likely to occur. One case is, however, chosen as the best case. A nutrient budget and estimates of the magnitudes of the new production are presented for this case.

[1]  K. Koltermann,et al.  The first oceanographic section across the Nansen Basin in the Arctic Ocean , 1989 .

[2]  Göran Björk,et al.  A One-Dimensional Time-Dependent Model for the Vertical Stratification of the Upper Arctic Ocean , 1989 .

[3]  L. Anderson,et al.  Nutrient regeneration in cold, high salinity bottom water of the Arctic shelves , 1988 .

[4]  D. Quadfasel,et al.  Outflow of dense water from a Svalbard fjord into the Fram Strait , 1988 .

[5]  A. Stigebrandt,et al.  A model for the dynamics of nutrients and oxygen in the Baltic proper , 1987 .

[6]  J. Swift,et al.  Ventilation rate of the deep Arctic Ocean from carbon 14 data , 1987 .

[7]  R. Macdonald,et al.  The distribution of nutrients in the southeastern Beaufort Sea: Implications for water circulation and primary production , 1987 .

[8]  L. Anderson,et al.  On the origin of the chemical properties of the Arctic Ocean halocline , 1986 .

[9]  R. Sambrotto,et al.  Large Yearly Production of Phytoplankton in the Western Bering Strait , 1984, Science.

[10]  H. Göte Östlund,et al.  Arctic Ocean water mass balance from isotope data , 1984 .

[11]  E. Carmack,et al.  On the halocline of the Arctic Ocean , 1981 .

[12]  J. K. Dawson.  Vertical distribution of Calanus hyperboreus in the central Arctic Ocean1 , 1978 .

[13]  T. G. Owens,et al.  Nutrient transports through Lancaster Sound in relation to the Arctic Ocean's reactive silicate budget and the outflow of Bering Strait waters1 , 1975 .

[14]  D. C. Burrell,et al.  Chemical characteristics of water masses in the Amerasian Basin of the Arctic Ocean , 1970 .

[15]  H. Craig.  Abyssal carbon and radiocarbon in the Pacific , 1969 .

[16]  G. Mathieu,et al.  OXYGEN ISOTOPE COMPOSITIONS OF FORAMINIFERA AND WATER SAMPLES FROM THE ARCTIC OCEAN. , 1969 .