1920 



Forcers; on Condition of Sea-water 



381 



bathing Ulva had a pH of 7.77 and an oxygen content of 3.57 cc. per 

 liter, or a pH of 0.16 and an oxygen content of 0.84 cc. per liter lower 

 than that of sea-water in the main channel only a short distance away al 

 the same time. But in three hours despite the cloudy weather the pH 

 had increased to S.95 and the oxygen content to 11.45 cc. per liter of 

 water bathing Ulva in the same locality with only 20 centimeters greater 

 depth. The same relation was shown by the eel-grass. These observa- 

 tions and those made at stations Q, D and A will help to explain the non- 

 conformity of the pH and oxygen content at different depths. 



Table 8 gives the determinations made in Upogebia pugetensis holes 

 at low tide. The pH was always found to be below normal and the oxygen 

 content was very materially lowered, the highest found being 0.75 cc. per 

 liter and the lowest 0.15 cc. per liter. This is in keeping with experiments 

 performed on the respiration of marine invertebrates by Moore, Edie, 

 Whitley and Dakin (1912) and by Henze (1910) when animals were kept 

 in closed vessels. 



Table 8. The hydrogen-ion concentration and. the oxygen content of 

 the water in Upogebia holes at low tide 



In recent years much work has been done showing the great impor- 

 tance of the hydrogen-ion concentration in physiological and chemico- 

 physiological processes in general. Bacteriologists and those working on 

 enzymatic and fermentation processes have long since learned the neces- 

 sity of taking the hydrogen-ion into consideration. The sea-water can be 

 considered as a vast medium in which the physiological processes of the 

 marine organisms are taking place. Or it can be considered as a biological 

 fluid with a buffer action somewhat less than that of the blood of verte- 

 brates. One can hardly doubt that if one is going to make an exhaustive 

 study of the biology of the sea or sea-water that the hydrogen-ion con- 

 centration is one of the important factors with which it is necessary to 

 reckon. Attention has been called to the importance of the hydrogen-ion 

 concentration of the sea-water by Loeb (1903, 1906), Moore, Roaf and 

 Whitley (1905). Delage (1906), Herbst (1906), I.oeb and Wasteneys 

 (1911), Warburg (1911) and others for the first stages of development 

 of certain of the marine animals. Each organism seems to have a definite 

 range of hydrogen-ion concentration within which development can take 



