The surface discoloration of the water is not uniform, 

 but shows in patches or lines. This effect is believed partly 

 due to the variation in depth of the aggregations of organisms 

 as a result of internal wave action, as well as to their varying 

 concentrations . 



On one occasion, 30 May 1961, an especially heavy bloom 

 of phytoplankton discolored the near-surface layers of the 

 sea in the vicinity of the tower. The maximum turbidity was 

 slightly below the sea surface, but bands of red water were 

 separated by clear or only slightly red water (fig. 15). The 

 surface showed more dense coloration at position B near the 

 slick and parallel to it than at position A preceding it. The 

 water under and slightly behind the slicks (areas C, D, and 

 E) was clearer than adjacent water. Following this area 

 (area F), the water became red again, but not with the in- 

 tensity of the band just forward or landward of the slick. 



SEA SURFACE SUCK 



DEPTXOFMRMOCUNE 



DIRECTION OF INTERNAL WAVE PROPAGATION 



-4 IMIN k- 



Figure 15, Observations from theUSNEL tower on 

 30 May 1961 of an internal wave, its associated slick, 

 and red water. The shaded areas represent different 

 degrees of discoloration. 



19 



