watertight integrity. The clear quartz window in the camera case is examined frequently 

 for flaws and strain cracks caused by excessive applications of high pressure, sharp blows, 

 or improper mounting. It is advisable to allow the camera case to warm up gradually on 

 deck after each deep lowering before opening-up procedures are commenced. This will 

 reduce or eliminate condensation of moisture on camera parts and electrical supplies. 



Limitations 



Many factors work singly or together to limit the usefulness or effectiveness of all 

 deep-sea cameras. Weather and sea conditions determine the feasibility of each 

 operation. Underwater conditions such as sea-floor relief, depth, outcrops, rock or 

 sediment type, bottom slope and contact act to limit or increase the number of pictures 

 obtained on each lowering. Vital exposed moving parts of the camera unit, located 

 within the open construction of the frame for protection may suffer occasionally from 

 abrasion and contact with external objects. Deeper lowerings increase the chances for 

 kinks and snarls in the wire lowering rope. Only rapid indication of contact with the 

 bottom will provide the control to keep the wire lowering rope in good condition. 



APPLICATION OF THE CAMERA TO THE STUDY OF 

 OCEAN-FLOOR ENVIRONMENTS 



The NEL Type III Camera now makes it possible to extend the study of marine 

 environments to depths beyond the limitations of most existing cameras. Deeper bottom 

 features of the continental shelf, continental slope, and abyssal deeps west of San Diego, 

 California, are now being photographed to help reveal the nature of micro-relief on 

 the ocean floor, movement and identification of materials settling to the bottom and 

 the identification and distribution of biological life on, near, and in these modern 

 marine sediments. As the camera continues to be a relatively inexpensive and practical 

 means of investigating the small-scale features of the deep sea floor, improved photo- 

 graphic equipment helps to obtain views which exhibit the greatest amount of natural 

 detall.iO'" 



Bottom photographs are revealing how burrowing organisms, fish, and other 

 biological life are mixing up and moving bottom sediments; how sediments are being 

 moved along the bottom by currents and down-slope by slumping, sliding, and earth- 

 quake jarrings. Relative grain sizes of bottom materials are revealed. Greater bottom 

 coverage per single lowering of the camera is revealing the distribution of specific bottom 

 materials and biological life. Various forms of biological life living on, near, and in 

 the bottom sediments are being identified from improved underwater photographs 

 (fig. 9). 



CONCLUSIONS 



The development of the NEL Type III Deep-Sea Camera and its scientific appli- 

 cation to the solution of ocean-floor environmental problems have been justified by the 

 results obtained. The compactness, small size, light weight, and ease of operation and 

 maintenance of the camera permit more extensive field work to be carried on by only 

 a few operating personnel. Relatively small vessels equipped with only 3/16-inch- 

 diameter wire lowering ropes and comparatively light winches are being utilized suc- 

 cessfully for deep-sea photographic operations. Improvements in camera design, equip- 

 ment, and operational techniques are continuously being made to further the needs 

 of oceanographers engaged in the study of sea-floor features. 



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