THE BALTIC SEA 



283 



It is interesting to note that the ratio of the amount of carbon dioxide 

 formed at this depth to the oxygen consumed is about 0-9, which corresponds 

 to the respiratory coefficient of the organisms inhabiting the depths of the 

 Baltic Sea ; this has been confirmed by experiments with fish. 



The acid conditions of the deep Baltic waters have a characteristic effect 

 on the process of the decomposition of mollusc shells (Grippenberg, 1934). 



Fig. 127. Distribution of carbon dioxide (cm 3 /l.) in 

 near-bottom waters of Baltic Sea, May to July 1922 

 (Schulz, 1935). 



This process has also been observed to be strongly developed in the deep part 

 of the Kara Sea. 



The summer distribution of oxygen and carbon dioxide, and the concen- 

 tration of hydrogen ions in the bottom layer of the Baltic Sea, are shown in 

 Figs. 126, 127 and 128. 



The Gulf of Bothnia is separated from the rest of the Sea by a shallow 

 ridge, which does not let through the deep saline waters from the west ; this 

 affects its hydrological conditions. 



As shown in the three figures given, the gas conditions in the deep layers 

 of both Bothnian depressions are much more favourable than in the southern 



