Dissolved oxygen values measured during 1963 in the eastern regions 

 of the East Siberian Sea were somewhat higher than those observed 

 in the Laptev Sea a few weeks later. The highest content measured 

 was 12.64 ml/1 at 5 meters on station 44. Using Carpenter's saturation 

 values this figure yields a saturation in excess of 147%; however, 

 most other saturation values calculated for the same region were 

 under 130%, as shown in figures 24 and 25. 



The highest dissolved oxygen value measured in the East Siberian 

 Sea during the 1964 BURTON ISLAND cruise was at 20 meters on station 

 65. At this station, an oxygen concentration of 9.55 ml/1 or slightly 

 in excess of 113% saturation was noted. 



In 1963, saturation values generally increased seaward from the 

 Siberian mainland and toward the eastern regions of the East Siberian 

 Sea. No clear relationship was observed between the relatively low- 

 salinity, high-temperature water from the Indigirka and Kolyma Rivers 

 and dissolved oxygen distribution during either year. This may 

 be partly attributable to the station interval employed. 



Supersaturation observed in 1963 was limited entirely to the 

 upper 25 meters in the eastern East Siberian Sea and primarily to 

 the upper 15 meters in the sea's shallower western regions. The 

 water column above these depths was supersaturated at most stations 

 occupied. 



Supersaturation noted in 1964 also was observed entirely above 

 25 meters, but it appeared discontinuous from the surface to that 

 depth. Slightly supersaturated water was noted on many stations 

 at depths between 4 and 23 meters with undersaturated water above 

 and below. This water sometimes occurred only at a single observed 

 depth within this interval, but more frequently it appeared at several 

 consecutive depths. 



Observed dissolved oxygen supersaturation most likely can be 

 attributed to photosynthesis. Greenish-brown biologic material was 

 observed in the water and on ice floes in the East Siberian Sea during 

 1963 and 1964 similar to that noted in the Laptev Sea. Excessive 

 particulate content was evident in sea water samples collected at 

 all depths. A biological relationship is further suggested by the 

 discontinuous nature of the dissolved oxygen supersaturation observed 

 in 1964. 



Sverdrup, in 1922, noted oxygen supersaturation in the East Siberian 

 Sea and attributed the phenomenon to phytoplankton assimilation processes. 

 He observed a marked decrease in supersaturation between the years 

 1922 and 1923 and suggested that heavy ice cover in 1923 served to 

 limit biologic productivity (Sverdrup, 1929). Probably this was 

 also a factor in the decrease in supersaturation observed between 

 1963 and 1964 since ice cover was extensive in the East Siberian 

 Sea during 1964. 



33 



