- No. 2. SPITSBERGEN WATERS. 103 



the vertical circulation during the winter and has been cooled by the 

 radiation of heat from the surface, and by contact with ice. This cold 

 polar water cannot therefore be expected to contain comparatively much 

 oxygen, because in the winter, when this water was near the surface, 

 there is little light, and where the sea is covered by ice (and snow) the 

 sun is hindered from penetrating into the underlying water-layers and 

 consequently very little phyto-plankton can be developed, even in the 

 summer, as was proved during the Fram-Expedition 1893 to J 896. Where 

 the water-layers receive admixture of water formed by the melting of ice 

 we must also expect that their amounts of oxygen are somewhat reduced, 

 because ice, and consequently also its melting-water, contain comparatively 

 little oxygen. 



At Stats. 56 and 57 the percentage of saturation was decreasing with 

 increasing depth as far as our observations go, but the actual amount of 

 oxygen in the sea-water was greater at 500 and 700 metres at Stat. 57 

 than at loo metres at Stat. 56, although, to judge from the temperatures 

 and salinities, there seemed to be approximately the same kind of water 

 at the different levels at both stations (see Fig. u). It seems therefore 

 probable that in this region the actual amount of oxygen was distinctly 

 greater at 500 metres, and even somewhat greater at 700 metres, than at 

 100 metres. But the temperature (4.47 C.) was much higher at the latter 

 depth, and the water there (with salinity 35.02 / 00 ) had evidently been 

 carried from the south by the Atlantic Current, while the water at 700 

 metres belonged to the upper layers of the regular deep-water of the 

 Norwegian Sea, having the usual salinity of 34.91 / 00 and a temperature 

 of 0.08 C. 



The water at 500 meters, with a temperature of 1.22 C., might be 

 expected to have been formed to some extent by an intermixture of the 

 overlying Atlantic water with the underlying deep-water; but this is hardly 

 possible, because its amount of oxygen (7.23 cc.) is considerably greater 

 than those found both at 100 metres (6.75 cc.) and at 700 metres (6.96 cc.). 

 It must evidently have come from some other part of the sea where it 

 has been more or less intermixed with the upper layers, nearer the sea- 

 surface. 



The correctness of this view seems to be supported by the obser- 

 vations at Stat. 43 (80 20' N.) north-west of Spitsbergen, where waters 

 of much the same type, with temperatures between 1.36 C. and 1.83 C. 

 and salinities between 34.83 / 00 and 34.92 / 00 , were found at all depths 

 between 100 and 540 metres, with amounts of oxygen decreasing from 

 7-35 to 7-12 cc. per liter. It is evidently also the same type of water 



