1200 



TIME 



Sample time-depth plots of water transparency at the tower during a 27-hour period show 

 (A) the early stages of a Gonyctulcix plankton bloom with maximum concentration just 

 below the surface, and (B) the corresponding water temperature structure (heavy lines) in 

 degrees F. Transparency less than 30 percent is grey. The greatest plankton concentra- 

 tion occurs at the level of maximum temperature gradient. 



SEA SURFACE SLICK 



Red water with maximum turbidity slightly 

 below the surface is separated by bands 

 of relatively clear water beneath the 

 sea-surface slick. This patchiness in 

 turbidity is caused by vertical currents 

 associated with a passing internal wave. 



10 



20 



*■ I 



__ 



1 



-*. ■*■ -*- 





[••■■•■"' ■■- 









f DEPTH OF 



THERMOCLINE 



DIRECTION OF INTERNAL 



k 



rVAVE PROPAGATION 



81 



