466 CLAKKE AND DENTON [CHAP. 10 



changes in the plane of polarization of light or whether they simply responded 

 to changes in the pattern of scattered and reflected light which changes in 

 polarization had produced. It is now thought that some of the responses which 

 had previously been described were responses to changes in the pattern of light 

 (Baylor, 1959). The work on animals has greatly stimulated work on the 

 polarization of light in the sea (IvanoflF, Jerlov and Waterman, 1961). Ivanoff 

 and Waterman (1958) have shown that, in general, linear polarization is 

 maximal near the surface, where it may in clear water attain 60%, and di- 

 minishes rapidly in the first 10-40 m and after that decreases slowly to some 

 equilibrium value. They conclude that the submarine linear polarization arises 

 through scattering, for the degree of polarization decreases as the dififuseness of 

 underwater light increases, i.e. decreases with depth, with cloudiness of the sky, 

 with turbidity and at the wave-length of greatest penetration. 



In this brief survey we have principally described experiments dealing with 

 the open oceans rather than with those made in coastal water, for it is in the 

 study of the deep sea that the ratio of the newer knowledge to the older is 

 probably most great. We have, even so, only been able to indicate with a few 

 examples the considerable progress which has been made in recent years in our 

 study of the relationships between animals and light in the sea. 



References 



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