Charles S. Yentsch 



Physical Oceanograph ic Laboratory 



Nova University 



Fort Lauderdale, Florida 



Studies in our laboratory concern photochemical events that 

 occur in Natural Ocean waters. The principal reaction is photosynthesis; 

 however, we are becoming aware of other reactions that are driven by 

 light energy. In the course of these studies we have developed 

 photographic techniaues which may be of interest to this group. 



To be brief, we have been able to convert three color densitometry 

 values taken from common color film into monochromatic data (see papers 

 by Baig and Yentsch and De Marsh in this volume). The technique depends 

 upon establishment of a mean monochromatic curve for the images to be 

 studied. In our case the image is the spectral absorption curve 

 typical for marine phytoplankton . The dominance of chlorophyll a 

 absorption in these spectra allows the establishment of a mean curve 

 where the deviation from the mean, at certain wavelengths is quite 

 sma 1 1 . 



We have also examined the amount of light and its spectral 

 characteristics, backscattered from the Bahamana Banks. These data 

 show that the influence of bottom reflection is of prime importance 

 to a depth of about 25 meters. Below this depth, total volume 

 scattering from the water column is the important factor. 



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