qualitative picture of the changes in salinity and ice thickness and that it should not be interpreted 

 as average amounts for different months. It is clear from figure 55 what gradual changes in thick- 

 ness and salinity the ice undergoes up to the moment which characterizes these elements in August 

 of the follovifing year. When analyzing the curves obtained in the chart, Malmgren came to the 

 following conclusions: 



New ice has the greater salinity on its surface the more rapidly the ice formation took place; 

 toward the bottom, the salinity decreases rapidly at first, and then more slowly; near the lower ice 

 surface, the salinity again increases, but, in ratio to the growth of new ice layers from below, the 

 salinity at a given point decreases to normal. During the winter, the ice salinity decreases gradu- 

 ally at all levels; during the summer, as a result of melting, the salinity of the surface layers 

 begins to decrease rapidly and these layers become almost fresh. A decrease in the salinity of the 

 lower layers occurs simultaneously. 



One more conclusion should be added to these: during the seepage of cold and concentrated 

 brine downward along the capillaries and the gradual rise of the temperature of the brine during 

 this, there is also a simultaneous decrease in the salinity of this brine due to the melting of the cap- 

 illary walls along which the brine flows. The latter condition, which increases the diameter of the 

 capillaries, at the same time assists in the destruction of the already weak lower parts of the ice. 



LITERATURE: 62, 104, 139, 178. 



Section 59. Composition of the Salts 



As we have seen, any change in temperature changes the amount and concentration of the 

 brine in the salt cells of sea ice. 



But these same processes also change the composition of the salts in sea ice. Actually, it is 

 known from Ringer's experiments that only a slight decrease in the temperature of sea water below 

 the freezing point is necessary to start precipitation of calcium carbonate from it, and when the 

 temperature of the brine is decreased below -8. 2°, sodium sulphate begins to precipitate out. It is 

 natural that at corresponding temperatures these salts will precipitate on the walls of the cells. 

 Inasmuch as the chlorides in sea water begin to precipitate only at temperatures lower than -23°, 

 these salts are preserved for a very long time in the brine of the cells and graudally seep downward, 

 decreasing the salinity of the ice in the course of time. 



Thus, we should observe a deficiency of the carbonates and sulphates, which had deposited on 

 the walls of the cells, in the melt water of sea ice, and a deficiency of the chlorides which had 

 seeped into the water along with the brine. 



Investigations of the ice in the Barents Sea, conducted by Laktionov in 1929, have led to the 

 results (average) shown in table 36. 



Table 37 shows (according to some of Laktionov' s analyses) the vertical distribution of the 

 separate components in sea ice. 



148 



