20 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I28 



down. In a well on the beach near Point Barrow it was 960 feet deep. 

 How far this permafrost extends out under the ocean is not known, 

 but as the shoreline at and adjacent to Point Barrow is evidently 

 receding southward and as the ocean water is generally colder than 

 freezing, it ought to be as far out as the shore has receded. 



A strong offshore wind would cause considerable upwelling, and 

 on one occasion when it lasted nearly three days, the continuous up- 

 welling brought several deep pelagic animals, including two specimens 

 of the octopus Cirroteuthis sp. near shore. 



SALINITY 



The salinity of the water of the Arctic Ocean is slightly lower than 

 that of other seas. This is attributable to several factors, chief of 

 which are the vast amounts of fresh water flowing into the Arctic 

 and the low rate of evaporation. 



Drainage from 4.5 million square miles of territory affects the 

 salinity of the water, but not so much as would be expected with so 

 many large rivers emptying into the sea. It may have more effect to 

 the north of the Siberian coast, where there apparently is a tendency 

 for the waters of Bering Strait to turn out toward Wrangell Island 

 and thus counterbalance the effects of the fresh water from the 

 Siberian streams. Also, it should be remembered that the Arctic Zone 

 is a desert, the precipitation at Point Barrow being only about 4 inches 

 a year, including the snowfall. 



Table 3 gives the highest and lowest salinities recorded for each 

 month covered by this investigation, 



A comparison of the highest and lowest salinities during August of 

 1948, 1949, and 1950 is of interest. Ice floes, which were present all 

 summer in 1948, kept the salinity lower than in the summers of 1949 

 and 1950, when no ice was present. These melt from the bottom and 

 unexposed sides as well as from the top and exposed sides, so that 

 the salinity of the water would be lowered around the floes to the 

 depth that they extend below the surface. 



However, the majority of the invertebrates of the Arctic Ocean 

 appear to be adapted to considerable change in salinity and it is only 

 when they come in contact with surface water of very low salinity as 

 the result of melting ice that they succumb. Under "Phylum Chaetog- 

 natha" it will be noted that the arrowworm Sagitta elegans was able 

 to survive when the salinity of the water reached 15.22 parts per thou- 

 sand but was killed when it dropped to 5.81. Also, under Annelida 

 mention is made of the polychaetes that were killed during the short 

 time required to haul the dredge through the few feet of surface water 



