In the Chukchi Sea, three of the six cores display changes 

 to coarser sediment from 10 to 46 inches below the sea floor. 

 The core taken in Kotzebue Sound shows a change to coarser 

 material taking place about 6 inches below the bottom. A de- 

 scription of the core samples is given in table III. 



Bottom Photography. An attempt was made to obtain a 

 number of bottom photographs with the underwater camera 

 at almost every station occupied by the USS NEREUS. How- 

 ever, at only two stations were photographs obtained in which 

 the bottom was clearly discernible. In the Chukchi Sea near 

 snapper sample NEL 520, a photograph (fig. 8) showed the 

 bottom to be composed of sand, gravel, and minor amounts 

 of silt. In the Bering Strait near snapper sample NEL 557, 

 a photograph (fig. 9) showed the bottom to be composed of 

 shells, gravel, and rock. Abundant bottom-living organisms 

 are present. It is noteworthy that both of these photographs, 

 and the sediment samples obtained close by, showed a coarse 

 bottom in these localities. At all other stations, the bottom 

 water was too turbid for the camera to penetrate even when 

 placed only three feet from the sea floor. 



Constant checking of the equipment showed that improper 

 functioning did not contribute to the inability to obtain good 

 bottom photographs. The fact that this inability was caused 

 by the turbid nature of the bottom water was further sub- 

 stantiated by lowering the equipment with the camera focused 



Figure 8. Bottom photograph taken in the Chukchi Sea at 

 station N13 (latitude 70° N, longitude 169° W), showing coarse 

 and poorly sorted bottom material. Note abundant bottom- 

 living organisms including crab in lower center portion of the 

 photo. 



Figure 9. Bottom photograph taken in the Bering Strait, show- 

 ing stony bottom with abundant bottom-living organisms. Shell 

 fragments are abundant, and the large pelecypod valve in 

 center of the photo has a sponge growing in it. 



