188 BIOLOGY OF THE SEAS OF THE U.S.S.R. 



White Sea is considerably less than that of the Barents Sea and, besides this, 

 it may experience considerable variation from year to year. Thus a comparison 

 of conditions of salinity in the central part of the Sea in 1922 and 1926 shows 

 that during these four years the salinity of the upper layer of water increased 

 considerably, while the lower layer maintained the same salinity {Table 79). 



Derjugin suggests that the ventilation of the deep floor layers of water is 

 accomplished in the main at the expense of the horizontal transference of 

 masses of water. The distribution of the bathymetric, cold and more saline 

 water masses in the White Sea is indicated in Fig. 82. As shown in the sketches, 

 the deep, saline water is isolated, and is not connected with the saline water 

 of the Barents Sea, since salinity is less in the southern part of the Gorlo. 

 In the Voronka and the Gorlo the salinity decreases from 34% on the side 

 towards the Barents Sea to 26% on the side towards the White Sea. But it is 

 possible that in winter an isohaline of 30% reaches the White Sea proper, and 

 that saline waters from the Barents Sea supplement the store of deep layer 

 water in the White Sea. Besides this one may conjecture a non-periodical 

 inflow of more saline deep waters from the Barents Sea into the White Sea. 



Oxygen 



The distribution of oxygen in the water column of the White Sea shows no lack 

 of it in the deep floor layers. It is true that observations are available only for 

 certain seasons of the year, and do not embrace the bottom layer itself. 

 Nevertheless one must suppose that the bathymetric layers of water of the 

 White Sea are sufficiently aerated. It has not yet been established how this is 

 ensured, if, as Derjugin suggests, the convectional currents affect only the 

 surface layers of water (not deeper than 50 to 60 m). Derjugin speaks of deep 

 horizontal currents ; but the nature of the latter remains uncertain, as well 

 as the extent to which they ensure the aeration of the water near the bottom. 



Oxygen in the White Sea is present in fairly large quantity throughout the 

 water column. It has not been possible to establish stagnation phenomena, 

 although the oxygen conditions of the true near-bottom layer still remain 

 obscure. It is agreed that the White Sea presents a rare example of a body of 

 water with a deep basin, separated by a high ridge from the open sea, and 

 without the presence of pronounced stagnation. 



The annual course of oxygen content in the Gulf of Kandalaksha has been 

 given by E. Sokolova (1939) (Fig. 83). Some decrease of oxygen in the deep 

 layer is observed in July and August. In the surface layer oxygen saturation is 



