396 ANNUAL REPORT SMITHSONIAN INSTITUTION, 19 63 



abundance of nutrients play a vital role in the production of many- 

 organisms. 



On the other hand, some marine species appear to be almost inde- 

 pendent of the usually recorded physical-chemical constituents in the 

 oceans. In areas where water masses come together, nutriently rich 

 waters may be forced to the surface to produce an abundant and 

 diverse fauna. Predators thrive on the concentrated food organisms, 

 and human food organisms may be unusually contaminated by waste 

 disposal into such aggregations. 



Discharging rivers bring important trace nutrients to the coastal 

 area, and these result in a large increase in the production of marine 

 organisms. In such areas it is obvious that caution must be exercised 

 with respect to the location of waste disposal sites. The shallow 

 waters near the shore provide a principal habitat of commercially 

 im^Dortant oysters and clams, as well as for valuable game fish. Dis- 

 posal of wastes in packages may provide an artificial reef that is 

 attractive to fishes. After benthic fouling organisms begin to grow 

 on the surface of such packages, a food chain relationship to man is 

 possible. The continental shelf and its overlying waters serve as a 

 habitat for many important game and commercial species. Since fish 

 populations shift their location diurnally and seasonally throughout 

 the shallow-water area, it is difficult to select any part of the con- 

 tinental shelf and give reasonable assurance that no human resource 

 will be adversely affected by waste disposal. 



The only real basis for oceanic disposal of wastes rests in the deep 

 sea beyond the continental shelf. Here in tropical and temperate 

 waters, the established layering processes and the paucity of com- 

 mercial or game organisms in the waters below 1,200 fathoms leads to 

 the conclusion that adequate mixing times (up to 1,000 years or more 

 in the North Pacific) must be present to dilute most pessimistic esti- 

 mates of the quantities of wastes to be produced during the next 40 

 to 50 years. 



As mentioned in the previous section, the chemical nature of the 

 wastes is very important. Particulate wastes will be trapped during 

 the normal activity of filter or mucous feeders and taken into the diges- 

 tive tract. If the particles are of such a nature that they can serve 

 in the metabolism of an animal, they may be retained. A substantial 

 portion of particles, particidarly cerium 144 and other rare earth 

 elements, pass on through the digestive tract. 



FATE OF RADIOACTIVE MATERIALS IN THE OCEAN 



In disposal of radioactive wastes into the ocean it is desirable to 

 make a "materials accounting" of the radioactivity. Only estimates 

 are available of the important parameters in many cases. Eadio- 

 active isotopes undergo decay to become stable elements. Decay is 



