The nitrate -nitrite values point up the difference in concentrations 

 that exists between Stations I and III. The lower values at Station I are at- 

 tributed to the utilization of nitrogen by denser growths of phytoplankton at 

 that station. Nitrite concentrations were considerably lower than nitrate- 

 nitrite v^alues and varied between stations and periods. 



Ammonia was found in only 1 1 of the 36 samples analyzed. Con- 

 siderable variation in concentrations existed between those samples in which 

 ammonia was found. No explanation can be offered for this patchy distribu- 

 tion other than perhaps streaks of ammonia originating from some organic 

 deconnposition. 



Measurement of the arabinose equivalent from the unfiltered sam- 

 ples shows that the production of carbohydratelike material occurred during 

 the daylight hours. A gradual increase in the concentration of this material 

 was evident during the hours in which photosynthetic processes were taking 

 place. No carbohydrate breakdown was apparent until just before dark. The 

 production of carbohydrates was greatest at Station I and least at Station III. 



Salinities were obtained from density and temperature data. These 

 values were quite variable, the greatest differences being noted at Station I. 

 Increasing salinity from Station III toward Station I was probably caused by 

 a poor water exchange coupled with excessive evaporation in the upper ex-^ 

 trennities of the lagoon. 



Samples were quantitatively analyzed for chlorophyll "a", which 

 had its highest concentration in the upper extremities of the lagoon, becom- 

 ing progressively lower at Stations II and III. The values obtained for Sta- 

 tions II and III remained fairly constant. When the bihourly chlorophyll "a" 

 values during daylight hours (periods 1-V) were averaged and compared with 

 those of the hours of darkness (periods 8-12), a significant difference was 

 noted only at Station I where production was markedly greater during the 

 daylight hours. These averages further indicate that chlorophyll "a" con- 

 centrations differ significantly from station to station. Station 11 averaged 

 74 percent of that of Station I for the 12 periods; Station III averaged 58 per- 

 cent of that of Station I for the 12 periods. 



Water temperatures followed the normal diurnal rise and nocturnal 

 fall. However, there was relatively little difference in temperature between 

 stations and between collecting periods during the study. The total difference 

 amounted to only 2. 3° C. It is doubtful that this slight fluctuation would have 

 a significant effect upon any of the values obtained. 



Air temperatures for each period were obtained by averaging the 

 temperatures recorded at each of the three stations. They followed the same 

 trend as those of the water, reaching a maximum of 31.3° C. and a minimum 

 of 26.9° C. 



The tide level fluctuated between 2. 81 feet and 0, 95 feet above mean 

 low tide. A flooding tide immediately preceded the study; the crest of this tide 

 coincided with the first sannple collected during period 1. Except for those 



79 



