Figure 20— Dissolved oxygen (mg.at./I.) at 200 m., fall 1963. (The 183- and 1,829-m. depth con- 

 tours are shown.) 



normally found at a greater depth had moved 

 shoreward in this area. Conditions near the 

 bottom were reversed from those at the surface 

 where the salinity was at a minimum and the 

 temperature was at a maximum. At 183 m. the 

 range of salinity was much smaller — between 

 33.67%= and 33.95%o — but the range of 

 temperature at 183 and 55 m. was the same, 

 1.0= C. The salinity did not vary significantly 

 along the coast and temperatures increased 

 only slightly toward the south — about 0.1° C. 

 Upwelling, therefore, was not taking place at 

 183 m. The range of values continued to de- 

 crease with depth. Changes in salinity ranged 

 ifrom 0.08%o at 914 m. to 0.07%<. at 1,829 

 m., and differences in temperature ranged 

 from 0.15° C. at 914 m. to 0.10° C. at 1,829 m. 



These minor variations indicated no significant 

 change in salinity or temperature near the 

 bottom along the Continental Slope during 

 spring between the Columbia River and Cape 

 Cook. 



Values of dissolved oxygen near the bottom 

 at 55 m. during spring were lowest off the 

 mouth of the Columbia River (fig. 22). This 

 situation appeared to corroborate the upwell- 

 ing of deeper water, although biological utili- 

 zation may have contributed to the low values. 

 Oxygen, like salinity and temperature, fol- 

 lowed no significant trend at a particular depth 

 along the Continental Slope. 



At 55 m., values of salinity, temperature, 

 and dissolved oxygen in the fall were signifi- 

 cantly different from those during spring. 



GEOSTROPHIC CIRCULATION 



243 



