30 Papers from the Department of Marine Biology. 



Attempts were made at Tortugas and continued at Minneapolis 

 to estimate the non-volatile buffers separately, and to find some 

 reliable data in the literature, but this work has not reached a state for 

 pubhcation. It was found that phosphates and sihcates are soluble 

 enough, but it seems impossible to find enough siHcate and phosphate 

 in sea-water to account for all of the non-volatile buffers, even though 

 we regard the results of analyses as being rough estimates. Borates 

 were found in Tortugas sea-water and in the Princeton Marine Aquarium 

 and in the Pacific Ocean by the senior author. An attempt was made 

 to increase the non-volatile buffer by the addition of phosphates, 

 but marine animals behaved abnormally in this water. The same was 

 attempted with sihcates, and plants grew luxuriantly in the artificial 

 sea-water. No more accurate data were found when the Tortugas 

 paper was sent to press (the paper was received for publication Sep- 

 tember 14), but about 6 weeks later the paper of Henderson and Cohn 

 appeared, in which it was stated that artificial sea- water containing 

 boron equivalent to 0.0015 boric acid had the same buffer value as 

 sea-water. This led us to make a series of electrometric titrations, 

 continuing those begun at Tortugas, on a series of natural and artificial 

 sea-waters under C02-free conditions. The results are given in 

 figure 4, and it was estimated from this and tonometer experiments 

 that Tortugas sea-water has a non- volatile buffer value much less than 

 0.001 m boric acid, whereas by the growth of diatoms and other marine 

 Protista in a pjTex flask the same water was reduced to less than this; 

 and Princeton aquarium water, kindly sent by Dr. L. R. Gary, had a 

 still lower non-volatile buffer value. It is not possible to determine the 

 exact boric-acid equivalent from figure 4, and in estunating that of 

 Tortugas water the Ph of artificial sea-waters and Tortugas sea-water 

 at the same CO2 tension were found to be about equal. 



We have not been able to obtain a sample of sea-water with as high 

 non- volatile buffer value as artificial sea- water of 0.0015 m boric-acid 

 content. Veatch reported evidence that the shore- water off the south- 

 ern California coast is in communication with unknown borax deposits. 

 Dr. William E. Ritter kindly sent us a sample of this water, and it was 

 found to give the same qualitative test for boric acid as any of the 

 other sea-waters examined. It had a non-volatile buffer value equiv- 

 alent to Tortugas sea-water. We feel justified, therefore, in the 

 assumption that the non-volatile buffer value of sea-water of fairly 

 normal salinity is a more or less constant quantity and is markedly 

 changed only when organisms are kept a long time in a relatively small 

 quantity of sea-water. The water at the surface of the ocean, where 

 most of the organisms live, is constantly being renewed by vertical 

 ocean-currents. 



On the assumption that the weak acids in the sea have a somewhat 

 comparable buffer value, the error that might arise in calculating the 



