collected during periods 11 and 12, the remaining samples were taken on the 

 ebb tide. Because of the length of the lagoon and the comparatively small 

 difference in tide levels, it is believed that only a very limited tidal exchange 

 takes place. 



MEAN LOW TIDE 



2 »■ 

 2 6- 

 2 4- 



5.0 



z.e 



-2.6 

 2.4 



22 



20 



i.e 



■10 



o.a 



\ 



31 5- 



310- 



u ""■ 

 S 300- 



!'". \^'- 



S 29.0-i;-->-- 



o 



„ 28.5 



UJ 28 



It 



S 275H 

 o 

 27 



26 5 



WATER AND AVERAGE AIR TEMPERATURE 



'^":_^ — 



-I 1 1 1 1 1 1 r 



31 5 

 -310 

 505 

 300 

 295 

 29.0 

 285 

 280 

 -27.5 

 27.0 

 26.5 



n 1 1 1 ', 1 1 1 1 1 1- 



0830 1030 1230 1430 1630 1630 2030 2230 0030 0250 0430 



Observations made on East Lagoon, Galveston 

 Island, during a 24 -hour cycle. 



80 



