ATMOSPHERIC GASES IN SEA-WATER 97 



variation in the solution of atmospheric gases in sea-water has 

 been studied by Fraulein Lovén. Algae in darkness can 

 absorb ail the oxygen présent, and are able to live in oxygen- 

 free water for sixty to seventy hours. Cod and Whiting kept 

 in an aquarium for six hours reduced the oxygen from 5* 18 ce. 

 to G' 19 ce. (in 18J litres), and inereased the carbonic aeid from 

 39" 56 e.e. to 44" 17 ce At this stage they died. 



Smaller fish can endure a réduction of oxygen to 0"8 ce, 

 and will survive if afterwards they are plaeed in normal sea- 

 water. Broadly speaking, in the présence of sunlight zoo- 

 plankton inereases the carbonic acid in sea-water, while the 

 phytoplankton lessens it, 



The chief cause of variation in the amount of carbonic aeid 

 in the sea is the atmosphère. Estimâtes hâve been made of 

 the total amount of carbonic aeid présent in the sea and in the 

 atmosphère respeetively, and it is ealculated that the former is 

 twenty-seven times as great as the latter. There is almost 

 certainly an exchange of carbonic acid between the sea and 

 the air, dépendent on the vapour tension of the carbonic acid 

 in the sea and air respeetively to one another. It has been 

 ealculated that the enormous pollution of the atmosphère 

 produeed by the burning of eoal (780 million metric tons 

 were eonsumed in 1901) is more than absorbed by the 

 sea, whieh therefore acts as a regulator of carbonic acid in 

 the atmosphère. The vapour tension of the carbonic acid 

 in the air is less over the océans and their coasts than over 

 the land. 



When a comparison is made of the volume of carbonic aeid 

 in sea-water, and when the variations are referred to their 

 probable causes, it is found there are three — Salinity, 

 Température, and the Plankton. 



The International investigations show elearly that the 

 amount of carbonic aeid présent is directly dépendent on the 

 salinity. 



