128 



Atomic Radiation and Oceanography and Fisheries 



wire touches bottom. Oceanographers seldom 

 hope to place their sondes and coring tools 

 upon any pre-selected topographic detail of 

 small area. However, it is quite likely that a 

 technique can be perfected for dragging a de- 

 tecting instrument along the bottom in many 

 areas of the oceans' floor, and with a dragged 

 detector a large region might be traversed rap- 

 idly, and tagged water masses near the sea floor 

 might be located and surveyed. A proposal for 

 tagging bottom waters now will be outlined. 



Difficulties in tagging bottom waters 



Fortunately, little hazard to human popula- 

 tions would result from putting into the deep 

 bottom waters in certain latitudes almost any 

 amount of activity which might be readily 

 available in the near future, or which would be 

 easy to handle safely ashore and on ordinary 

 surface vessels. After all, these amounts would 

 be only the feeble forerunners of what may 

 have to follow. 



The problem is that of displaying even a rela- 

 tively large radioactive source economically in 

 face of the immensity of the abyssal reaches. 

 One can think of many things which must not 

 be done; heavy, radioactive liquid cannot be 

 merely poured overboard, for example. Match- 

 ing density at intermediate layers or attempting 

 to insert a strata at a selected depth also would 

 appear experimentally difficult in view of the 

 limited knowledge presently available; an un- 

 equilibrated liquid mass might wander about 

 like a sinking dinnerplate — and soon become 

 lost. In the absence of the restraining forces 

 found in more stable waters, the pouring of 

 streams of dense solution downward from a 

 height above the bottom, or alternately the re- 

 leasing of lighter material upward from the 

 bottom would surely cause mass motion which 

 might not cease until the streams had moved 

 long distances and perhaps had curled into con- 

 figurations quite unsuited as initial boundary 

 conditions for water tracing experiments. Fur- 

 thermore, activity spread initially in more or less 

 vertical lines would make very poor targets for 

 detectors trailing on the end of wires three 

 miles long, and would be wasteful in terms of 

 radioactive material and of expedition time. 



One might, of course, carefully select a per- 

 fect basin, and might gently introduce into it 

 a dense radioactive solution. This certainly 



should be considered since only a small amount 

 of activity might suffice for tagging the waters 

 in a small basin and valuable information re- 

 garding motion and dispersion in basins might 

 result, but results would not lead to a realistic 

 picture of the large scale flow over bottom 

 which may have to disperse the wastes dumped 

 in the future. The results of an experiment set 

 up in this way would be inadequate, and, in 

 fact, might be misleading in a dangerous direc- 

 tion. 



Production and use of horizontal line-sources 

 near the bottom 



"Operation HARE and HOUND" 



It is evident that distribution of activity in a 

 horizontal line near the bottom would be most 

 easy to intercept by a detector dragged along 

 the bottom, and it appears also to be something 

 which would be relatively easy to produce, and 

 economical. It should be possible to hold tagged 

 water near the bottom by mixing it with a very 

 dense solution; and there are two ways im- 

 mediately evident for effectively spreading 

 streaks of dense solution for long distances over 

 the bottom terrain. 



Figure 3 illustrates the two methods proposed 

 for tagging bottom water, and the method pro- 

 posed for locating the tagged masses later. The 

 Ship B' is shown dragging a "Hare" D, across 

 the bottom leaving behind a streak of contami- 

 nated water. Alternately, Ship B is shown just 

 after it has dropped to the sea floor a specialized 

 water blending device which might well be 

 called a "quern" ^, C, which generates for a 

 few minutes or hours, a stream of dense, radio- 

 active solution on the slope of a carefully se- 

 lected large topographical ridge b — d ; this 

 stream flows away very much like one of the 

 submarine currents which are now called "tur- 

 bidity currents" by geologists. Violence of this 

 sort of free current might theoretically be con- 

 trolled through wide limits by adjusting the 

 densities of the solution. The essential features 

 of a water-tagging quern are shown in the 

 upper right of Figure 3. Radioactive material, 

 AS, is combined in predetermined proportions 

 with a heavy salt solution by metering pump, 

 P, and the two are then fed to a fan-type mixer, 

 and are there blended with a large volume of 



1 Old English name for a mill for grinding all sorts 

 of things. (RuggoflF, 1949.) 



