As discussed above (Section IV), the Arctic Ocean's major inflow 

 passes through the EDISTO survey region, and the deep waters of the 

 Polar Basin appear to be supplied by a northward flow of Arctic Bottom 

 Water. These inflows consist primarily of waters which originated 

 in the Atlantic. Estimates vary, but data presented by Coachman 

 (1962) indicate that a reasonable estimate for the proportion of 

 water originating in the Atlantic in the waters of the Arctic Ocean 

 would be 70 to 80%. Thus, even in the waters of the East Greenland 

 Current the proportion of water from the Atlantic Ocean should be 

 high, and the Arctic Bottom Water and the waters of the West Spitsbergen 

 Current should contain an even greater proportion of water from the 

 Atlantic than the 70 to 80% given for the Arctic Ocean. In view 

 of the above, it is not surprising that micronutrient concentrations 

 in the survey area (Figs. 7, 9, 10, and 11) were fairly low because, 

 as is well known, micronutrient concentrations in the North Atlantic 

 also are low. Data gathered in the Norwegian Sea during a 1963 EDISTO 

 survey 7 confirm the view that the inflowing Atlantic Water has low 

 micronutrient concentrations. Here, in waters with salinities 

 high enough to indicate that they were part of the Atlantic inflow 

 (««35.2%o), the highest reactive phosphorus concentrations were approximately 

 1 jug-at/liter, the highest nitrate values were about 14 jug-at/liter, 

 and the highest reactive silicate values were about 7 ;ug-at/liter . 

 It is true that the higher nitrate and reactive phosphorus concentrations 

 in the Arctic Bottom Water were slightly greater than those just 

 mentioned and that maximum reactive silicate concentrations were 

 considerably greater. This is to be expected, however, and does 

 not necessarily indicate the presence of large quantities of waters 

 not originating in the Atlantic. For example, it is quite possible 

 that some of the micronutrients in the Atlantic Water discussed above 

 had not yet been regenerated since all of the samples mentioned here 

 were collected during the warmer months. The differences in maximum 

 nitrate and reactive phosphorus concentrations were slight, and it 

 is not surprising that large maximum reactive silicate differences 

 were encountered. This could be due to the following factors: 

 a) Regeneration of reactive silicate may proceed at a slower rate 

 than that of nitrate and reactive phosphorus; b) Re-solution of 

 silica from the bottom (Richards 1958) ; and c) Diatom frustules 

 sinking faster than organic material. 



As Figures 7, 9, 10, and 11 indicate, micronutrient concentrations 

 generally increased with depth, and concentrations in the more shallow 

 layers were often quite low. This, of course, is to be expected since 

 photosynthetic processes were almost certainly lowering micronutrient 

 concentrations in the near surface strata during the survey. Pronounced 

 micronutrient maxima and a significant oxygen minimum were not present 



Although Arctic Bottom Water originates in the Greenland and Norwegian Seas, a consideration 

 of the mass transports and current systems already described indicates that this water mass is formed 

 mainly from waters originating in the Atlantic. 



National Oceanographic Data Center cruise No. 31167. 



38 



