I 



SAUNfTY (o/oo) 



Fig. 7. (A) Temperature ('€) and salinity ("/,„); (B) nitrate (n g-at/1) and 

 salinity (7(x,) plot for all stations sampled in the Bering and Chukchi 

 Seas. 



SAijNrrr (o/oo) 



Fig. 8. (A) Silicate (|i g-at/l) and salinity (7i„) plot; (B) phosphate (|i g-at/1) 

 and salinity ("/„,) plot for all stations sampled in the Bering and 

 Chukchi Seas. 



The silicate-salinity diagram for all samples (Fig. 8A) 

 shows the range of silicate to be between 0.5 and 60 |ag-at/l for 

 most samples between 3 1 and 33 "/„„. The low salinity Alaskan 

 Coastal water had values below 20 |ag-at/l and the deep Bering 

 Sea contained concentrations above 230 |ag-at/l. In contrast, 

 the range of phosphate concentrations (Fig. 8B) was 0.23 to 

 about 3.5 ug-at/1. The uniform distribution of phosphate 

 compared to nitrate is probably due to the rapid regeneration of 

 phosphate in the water column. 



Deep Bering Sea 



The South and East Polygons in the Bering Sea had 

 stations with depths approaching 4,000 m. The vertical profiles 

 of nitrate and silicate (Fig. 9B) provide some insight into the 

 nutrient gradients in the deep Bering Sea. The concentrations 

 of nitrate and silicate were very similar in the upper 100 m 

 between the two polygon locations; however, the East Polygon 

 had larger nitrate and smaller silicate concentrations compared 

 to the South Polygon. The resulting plot of nitrate/silicate ratio 

 with depth (Fig. 9A) clearly shows the differences. The low 

 oxygen concentrations present in the South Polygon (Fig. 1 1 A) 

 are more conducive to denitrification process, so it is likely that 

 the nitrate has been lost from the deep water by this process. 



The near-bottom waters near the South Polygon had previously 

 been observed to contain a layer of slightly less saline water 

 near the bottom (Park et ai. 1975). The very distinct vertical 

 distributions make further sampling in these regions a necessity. 



The vertical phosphate distributions in the deep Bering 

 Sea (Fig. lOB) also tend to be elevated in the East Polygon 

 compared to the South with values greater than 3 |imole/l. The 

 dissolved inorganic nitrogen (DIN)/phosphate ratio showed 

 that most deep ocean values were at or above 16:1. especially 

 in near-bottom water where the ratios were >20: 1 . 



The vertical distributions of pH (Fig. 1 IB) and dissolved 

 oxygen (Fig. 1 1 A ) in the deep Bering Sea reflect the relatively 

 high rates of primary production in the surface waters and the 

 slow rate of water circulation at depth. These distributions 

 result from the consumption of dissolved oxygen and the 

 respiratory release of carbon dioxide as particulate matter sinks 

 into the deep sea. Since these parameters are both closely 

 associated with the decomposition of organic matter it is not 

 unusual for their relationships with salinity to be similar 

 (Figs. 12A.B). The highest salinity waters in the deep Bering 

 Sea have increased values of both pH and dissolved oxygen and 

 may be related to bottom water renewal processes from the 

 North Pacific Ocean. 



45 



