On Changes in the Sea and Their Relation to Organisms. 231 



stations B and H samples of water were obtained which were 20 per cent 

 undersaturated and 69 per cent oversaturated respectively. 



Contrasted with the behavior of oxygen, no certain effect of the 

 atmosphere on the C0 2 of the water as indicated by the pH was observed. 

 At station A the oxygen curves were flattened out on July 13-15, due 

 to high winds, but no flattening is observed on the pH or C0 2 curves. 

 On going north into colder waters no fall in pH was noted, except on a 

 very cloudy day at the mouth of the Chesapeake Bay and in the pol- 

 luted water off New York Harbor, neither of which can be considered 

 normal conditions. Palitzsch, however, noted that pH fell from 8.08 

 to 8.13, with more extreme drop in temperature in the North Atlantic 

 and North Sea. This is not due to a difference in standards, since he 

 found the pH of the Altantic at about 41 north latitude and of the 

 Bay of Biscay to be 8.22 and 8.25 respectively. 



No local effect of the C0 2 tension of the sea on the C0 2 of the air was 

 observed. The wind reaching Tortugas blew over the Florida Keys 

 and alternate areas of water of C02 tension =3 to 3.5 in the morning 

 and 2 to 3 in the afternoon. The CO 2 of the air varied from 2.8 to 3.5 

 without any relation to time of day. Part of this variation may have 

 been merely the expression of technical errors, but a large number of 

 duplicate experiments, and of experiments designed to show the limit of 

 error, failed to support the idea that the variations were entirely due to 

 technical errors. The CO 2 of the air was determined colorimetrically 

 with 24 mm. sealed tubes containing the standards. The objection 

 might be raised that the expanse of water of the same C0 2 tension was 

 not great enough to affect the air and that considerable time was neces- 

 sary to effect a change, and while one body of air was passing over the 

 sea, both morning and afternoon variations in the water affected it 

 alternately with neutralization of effects. The variations from day to 

 day might have been due to slight shiftings of the wind and also to 

 vertical currents in the air. In order to avoid such objections, Dr. A. 

 G. Mayer made determinations over the Pacific Ocean. The standard 

 tubes that he used were only 10 mm. in diameter, but the bicarbonate 

 solution was kept in a gold-lined Jena flask and had not changed when 

 tested on his return. The absolute standards may have been different 

 from those used at Tortugas, but the method was adequate to show 

 differences, provided equilibrium was always reached. The determina- 

 tions were taken at noon each day, except where otherwise stated. 

 The results of my calculations from his data are given in table 1 1 . 



From table 1 1 there probably may not be recognized any correlation 

 between C02 tension of the sea and of the air. The cause for this 

 may be that the apparatus was too crude or that exchange between 

 air and sea is entirely masked by currents in the air. If we regard the 

 air as sufficiently circulated to be of practically uniform composition, 

 the changes in barometric pressure would not cause significant changes 



