THE ORIGIN OF ORGANIC MATTER 43 



acids, to the concentration of bases combined with them (excess base over 

 strong acid)." They have worked out methods of determining the pH 

 of sea-water and therefrom the carbon dioxide-tension thereof. 



For many years the influence which the oceans may exert on the carbon 

 dioxide-content of the atmosphere has been a subject of much discussion. 

 If chemical reactions in the sea or the activity of hving organisms therein 

 influence the carbon dioxide-content of the atmosphere, it is evident that 

 such factors may be of great significance in the photosynthetic activity 

 of land plants. Carbon dioxide is continually being added to and lost 

 from the sea. Submarine volcanic springs and the action of marine ani- 

 mals, the latter forming normal calcium carbonate from bicarbonates, 

 both are among the factors which tend to increase the carbon dioxide-con- 

 tent, while the development of the marine flora tends to remove carbon 

 dioxide. According to a theory of Schlossing *^ the oceans serve as the 

 great regulators of the carbon dioxide-content of the atmosphere. Ac- 

 cording to this view, due to the presence of carbonates and bicarbonates 

 of the alkaline metals and alkaline earths, sea-water has the capacity of 

 absorbing or giving ofif carbon dioxide, depending upon the partial pres- 

 sure of this gas in the atmosphere. If the carbon dioxide-content of the 

 atmosphere increases, the excess will l)e taken up by the sea-water and if 

 there is a decrease in atmospheric carbon dioxide, this gas will be liberated 

 from the sea-water until equilibrium is reached again. In view of the 

 fact that complete concordance has not been attained in regard to the 

 carbon dioxide-content of the air over the sea and on land, there still exists 

 some difficulty in establishing the validity of Schlossing's theory. 



Krogh ** reported the carbon dioxide-tension of the water of the North 

 Atlantic corresponded to a carbon dioxide-content of the atmosphere of 

 0.023 per cent. This has been interpreted by Reinau to mean that the 

 carbon dioxide equilibrium is shifting in favor of sea-water and that the 

 oceans are actually absorbing carbon dioxide, although Schlossing stated 

 that the sea does not continuously absorb the carbon dioxide and that the 

 adjustment is a very slow one. Reinau *=^ concludes that there is little 

 connection between the carbon dioxide reservoir of the atmosphere and 

 that of the sea. In fact, he considers that the only regulator of carbon 

 dioxide is the life activity of plants and animals, and that the variations 

 in the carbon dioxide-content are to be ascribed entirely to the factor which 

 regulates "assimilation'' and "dissimilation" of carbon, namely, light and 

 heat, or, ultimately the sun. 



There appears to be little doubt as to the possibility of an interchange 

 of carbon dioxide between the sea and the atmosphere. The conditions 

 afifecting this equilibrium over long periods of time are, however, numerous 

 and apparently impossible to evaluate and correlate in a quantitative sense. 

 The possible significance of variations in carbon dioxide-content of the 



''Schlossing, Cnmpt. rend.. 90. 1410 (1880). 



" Krogh. Compt. rend., 139, 896 (1904). 



*•' Reinau, F... Kohlcnslhirc nnd Pflanzcn, p. 140. 



