TABLE 34. THE AMOUNT OF BRINE IN GRAMS IN 1 KG OF SEA ICE HAVING 

 DIFFERENT SALINITIES AND TEMPERATURE 



In using formula (2), and table 34, it should be clearly kept in mind that the salinity of the 

 brine 3 is determined only by the temperature of the ice, and that the salinity of the ice 5^ 

 depends on the amount of brine which is determined by the number and size of its cells. 



LITERATURE: 52, 62, 104. 



Section 58. Brine Migration 



As we have seen, sea ice consists of pure crystals, surrounding more or less equally dis- 

 tributed cells filled with brine. Since the ratio of the main elements in sea water of various salin- 

 ities is the same, the concentration of the brine in these cells should be the same at each given 

 temperature, depending neither on the salinity of the water from which the ice was formed nor on the 

 general salinity of the ice. 



Actually, we can consider each brine cell as being a closed vessel in which the processes fol- 

 low eutectic laws during a change in temperature. Thus, with each decrease in the temperature of 

 ice, pure ice separates from the brine in the cells and salts are precipitated in the sequence estab- 

 lished by Ringer's experiments (Section 7). With each rise in temperature, the ice which separated 

 out of the brine during a drop in temperatures melts, and the precipitated salts dissolve in the brine. 

 Other conditions being equal ,the salinity of the water from which the ice was formed affects only 

 the volume of the brine included in the brine cells. 



However, this scheme of phenomena is considerably complicated by the fact that separation 

 of pure ice within the cells completely filled with brine causes a certain increase in the volume of 

 the cell. Actually, fresh water increases its volume by 9 per cent on freezing. Thus, when the 

 temperature drops, and additional ice is separated from the brine, pressure is created on the side 

 walls of the cells which deforms the latter and squeezes brine out of the cells. On the other hand, 

 with each increase in temperature, empty spaces are formed in the cells which draw brine into 

 themselves from adjacent, mainly higher cells and also draw air from the atmosphere. Therefore, 

 processes determining many of the properties of sea ice occur constantly in sea ice due to the effect 

 of temperature changes. 



In particular, the subsequent formation of pressures within the cells, which squeezes the brine 

 out of them and formation of the empty spaces which draw out brine from the adjacent cells, (their 

 temperatures are related to the changes in the temperature of the ice) assist a gradual seepage of 

 the brine downward and a desalinification of the ice. As we have seen, this explains the decrease in 

 the salinity of the ice as it grows older. 



145 



