During the time of bottom water formation within the Greenland 

 Gyre, it should be borne in mind that it is quite possible for 

 waters with different temperatures to be formed (Helland-Hansen 

 and Nansen 1912). Naturally, mixing of these waters as they travel 

 from their source region could cause a rise in the minimum bottom 

 water temperatures encountered. 



4. Oxygen and Micronutrient Distributions. 



High oxygen saturation values were found at all depths throughout 

 the EDISTO survey region (Figs. 7, 10, and 11). This agrees with 

 the findings of others (Lationov, et al . 1960, Nansen 1915, Sverdrup 

 1933) and with the dynamics of the region. 



Since Arctic Bottom Water is formed at the surface in the same 

 general area, and since there is some evidence that its replenishment 

 is fairly rapid (Mosby 1959) , it is not surprising that dissolved 

 oxygen concentrations in the deeper layers were fairly high. Moreover, 

 because the bottom waters are formed during the cold months when 

 respiration exceeds photosynthesis, it is possible that a large portion 

 of any organic matter which may have been present originally is oxidized 

 before the waters contributing to the Arctic Bottom Water leave the 

 surface. It is not likely that the amount of organic matter which 

 sinks into the bottom water formation and is capable of being oxidized 

 is very great either. If it was, one would expect to find significantly 

 higher reactive phosphorus and nitrate concentrations in the deepest 

 layers as they travel away from their source region, but this does 

 not appear to be the case. 



Photosynthetic processes must have been adding oxygen to the 

 upper layers during the EDISTO survey and may have been partly responsible 

 for .the slight oxygen supersaturations sometimes encountered. Data 

 presented by Richards (1957) indicate that it is unlikely that photosynthesis 

 could exceed respiration at depths greater than 50 meters in the 

 EDISTO survey region. Since the waters in the area were well stratified 

 during the EDISTO survey, one might not expect any net addition of 

 oxygen by photosynthesis or by direct exchange with the atmosphere 

 to have extended much deeper than 50 meters. Consequently, it is 

 not surprising that oxygen saturations of 100% or greater were generally 

 found only in the upper 50 meters of the water column (Figs. 7, 10, 

 and 11). 



Even though they were less than 100%, dissolved oxygen saturation 

 values in the intermediate waters were still high indicating that 

 at least some of these waters may have been closer to the surface 

 in the not too distant past. 



The a t and depth values indicate that 10 Acrt /AZ in the upper 50 meters were often greater 

 than 1000 throughout the area, and extremely high stabilities were common in the surface layers 

 in the western portions of the survey region. 



37 



