igi2. No. 12. THE SEA WEST OF SPITSBERGEN. 57 



and — T-37^ C., while the saHnity was much the same as at Stat. 41 of 

 1910, between 34.36 and 34.51 ^/oo. Only at Stat. IV did the minimum 

 (at 60 metres) have practically the same temperature and salinit}' (0.51 " C. 

 and 34.51 ^ 00) as the minimum of Stat. 41. 



According to our view, there can be no doubt that these strata, with 

 a minimum temperature observed in the summer, are due to the vertical 

 circulation of the upper water-strata of the fjord during the winter. We 

 think that this is especialh' clearh- proved by the vertical series of obser- 

 vations at the above-mentioned Swedish stations, which demonstrate a 

 vertical distribution of nearly uniform salinities of about 34.4 ^ 00 from 20 

 metres down to 100 metres at Stats. V — VII. And these uniform condi- 

 tions occur as late in the season as Jul}' 24th and 25th, 1908, while in 

 September, at the Swedish Stat. Ill, of Sept. i, 1908 and at our. Stat. 41 

 of Sept. 6, 191 o (both stations at the mouth of the Ice Fjord) they have 

 nearly disappeared. 



The process is obviously the following: By the emisssion of heat from 

 the surface, the light surface-layers of the fjord are greatly cooled 

 during the autumn and early winter, and much ice is formed, covering the 

 fjord. By the growth of the ice the salinity of the surface-layers is gra- 

 dually increased, and the vertical circulation caused by the cooling of the 

 surface ma}' thus penetrate deeper and deeper, until at the end of the 

 winter it has reached a depth of between 60 and 100 metres, creating a 

 layer of nearly homogeneous water between the surface and this depth, 

 with a salinity of about 34.5 '^,00 and a low temperature, both of them 

 varying somewhat in the different parts of the fjord. In July 190T, for 

 instance, the salinity of the temperature minimum at 100 metres in the 

 middle of the Ice Fjord, and in Sassen Bay (Hjort's Stats. 88, 89, and 90) 

 was between 34.50 and 34.54 ^ 00, while in Green Harbour, and outside 

 the Ice Fjord, it was between 34.60 and 34.7o*'/oû at the same time, 

 and the temperatures varied between 0.55 and — 1.8° C. 



It is obvious that where the surface-layers of the sea have compara- 

 tively low salinities at the beginning of the winter, c. g. in Sassen Bay, 

 and in the Ice Fjord, the salinity of the whole homogeneous water-layer 

 created by the vertical circulation at the end of the winter, will be com- 

 paratively low, because the underlying water with higher salinity is gradu- 

 ally intermixed with the overlying less saline layers, while at places where 

 the surface-layers have higher salinities at the beginning of the winter, 

 c. g. in Green Harbour and in the sea outside the Ice Fjord (Hjort's Stats. 

 87 and 91), the salinity of the homogeneous water-layer at the end of the 



