100 FRIDTJOF NANSEN. M.-N. Kl. 



The observations are not sufficiently numerous to give a general 

 view of the distribution of oxygen in the different depths of the sea in 

 the Spitsbergen region; but some general features are demonstrated. 



The greatest quantities of oxygen always occurred in the upper 

 layers of the sea, at depths of 10 and 20 metres, with amounts mostly 

 between 8.19 and 8.34 cc. of oxygen per liter of sea-water, and there 

 was a supersaturation of 104 and 105% or even as much as io9/ . 



This supersaturation with oxygen in the uppermost layers of the sea 

 was already distinctly observed by Mr. H. TORNOE [1880, p. 19] "in the 

 surface-water of the northern tracts of the sea" investigated during the 

 Norwegian North- Atlantic Expedition 1876 to 1878, and he throught that 

 it must be the effect "of one or more causes as yet unknown". Similar 

 observations were also made by DITTMAR during the Challenger-Expedition 

 but he suspected that they might be due to observational errors. 



As was first pointed out by Prof. MARTIN KNUDSEN [1899, pp. 155 

 et seq.], the supersaturation is the result of the action of phyto-plankton, 

 that occurs in greatest quantities in the layers near the surface of the sea 

 and, below a certain level, rapidly decreases with increasing depth. 



Our observations give supersaturation with oxygen at 20 (and 10) 

 metres both in the fjords (Stats. 10, 45, and 50), in July and August, and 

 in the sea outside the coast, even where it was covered by drifting ice 

 as at Stat. 41 c; but the water at 20 metres at this station with a com- 

 paratively high temperature (2. 1 1 C.) had evidently come from the region 

 south of the ice. 



At the depth of 20 metres at Stat. 53, outside Bell Sound, the quan- 

 tity of oxygen (7.98 cc.) and the super-saturation (ioi.7/ ) were less than 

 at the same depth at the other stations farther north. This difference 

 may chiefly be due to the phyto-plankton. 



The fact that the water at the surface at Stat. 50, and at 5 metres 

 at Stat. 41 c was not saturated with oxygen (showing only 98% of satu- 

 ration) was probably due to cooling of the water. Mr. Gaarder has 

 always found similar conditions in the fjords of western Norway in the 

 autumn and winter. There is, however, a characteristic difference in this 

 respect between the surface-waters at Stat. 50, in the sheltered, quiet Bay, 

 where the surface was not stirred by wind and was much cooled, and at 

 Stat. 53 outside Bell Sound where the surface has evidently been stirred 

 by wind and waves, that would have effect here where the sea was not 

 sheltered by land or ice; the surface-water was therefore just saturated 

 with oxygen (ioo.4/ ) in spite of the cooling. 



