George L. Clarke 



Associate in Marine Biology^ Woods Hole Oceanographic Institution 

 and Prof, of Biology^ Harvard University. 



My special interest is in the application of light measurements 

 to the biological problems of the sea. Light in the ocean is derived 

 from the sun^ the moon, and the sky, and also from the luminescent dis- 

 charge of many kinds of marine organisms. The conditions of light in 

 the sea control the growth of the primary plant producers and influence 

 the behavior of many oceanic animals. The absorption, scattering, and 

 spectral distribution of daylight passing through the water are modi- 

 fied by dissolved and particulate matter, both living and non-living. 

 Our present investigations are concerned with measurements from ship 

 and aircraft of the spectrum of light back-scattered from beneath the 

 surface. Changes in the spectra in space and time are under scrutiny 

 as means for delineating water masses, detecting pollution, and evaluat- 

 ing chlorophyll abundance as an index of productivity. A summary of our 

 recent work on this subject is presented in tnis publication. 



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