380 



Ptib. Puget Sound Biol. Sta. 



Vol. 2, No. 54 



Table 6. The hydrogen-ion concentration of a lagoon at a depth of 

 10 centimeters. 



Table 7. The hydrogen-ion concentration and oxygen content of 

 sea-water bathing vegetation 



7. Effect of vegetation and animal organisms upon hydrogen- 

 ion CONCENTRATION AND OXYGEN CONTENT OF SEA-WATER 



Table 7 gives a few of the determinations made of the sea-water 

 bathing vegetation. By comparing this table with all other tables it is 

 found that the pH and oxygen content of the water bathing vegetation are 

 very materially raised during daylight by the photosynthetic activity of 

 the vegetation. This is in agreement with other workers (Palitzsch, 

 McClendon, Gaarder and others). There are some exceptions shown in the 

 case of the kelp, Nereocystis luetheana. These exceptions can possibly 

 be explained by the fact that the kelp selected for these observations was 

 located on the side of Brown Island nearest station J; and the water bath- 

 ing the kelp and that a short distance away might have had an entirely 

 different source due to the current. Determinations made early in the 

 morning of water bathing the Ulva and eel-grass showed that both the pH 

 and o.xygen content were lowered below that of the surrounding water 

 during the night. Tlie plus sign in the table indicates that the pH or the 

 oxygen content was higher than that of the surrounding water, and the 

 minus means that it was lower. On July 23, 1919, at, 6 :2.'5 A. M. the water 



