WASTES IN THE SEA — WALLEN 395 



cially in the kidneys. Cobalt 60 is concentrated in the liver and 

 kidney of hard clams. 



Biological activities of marine organisms are important to waste 

 disposal in the ocean. The ratios of the mineral salts of calcium, 

 sodium, and chloride are not much different when taken from any 

 part of any open-ocean area. On the other hand, biological nutrients, 

 such as nitrogenous compounds, phosphorus, and dissolved oxygen, 

 may vary significantly from one area to another. The Pacific Ocean 

 differs from the Atlantic by perhaps 2 percent in salinity, but the 

 deepwater concentration of phosphates in the Pacific is twice that 

 in the Atlantic. Phosphate concentration in the Mediterranean is 

 about one-third that of the Atlantic. This difference may be ac- 

 counted for by the sinking of dead organisms, and to a certain extent, 

 by the vertical migrations of marine species. 



Zooplankton and certain fishes migrate diurnally to a varying degree 

 in the oceans. Such migrations usually are limited to the upper 100 

 to 400 meters. Although less than one ten-thousandth of the radio- 

 isotopes present were attached to organisms as compared with those 

 dissolved in the water following Pacific tests, daily migrations with 

 rapidly exchanging isotopes may result in the transfer of substantial 

 quantities of radioactivity from one level to another in the ocean. 

 Seasonal vertical migrations also may affect such transfer. For 

 example a copepod, Calanus flnmarchiiis, lives for most of the year 

 at depths from 600 to 1,000 meters, but spawns close to the surface 

 from May to August. 



Fish migrate horizontally as much as 70 miles per day, and wastes 

 may be transported with them. Since the migrations of fishes are 

 related to their aggregations, which makes them more vulnerable 

 to being caught, it is necessary to estimate the effect of such movements 

 on the possible return of pollutants to man. 



A complex feeding interrelationship exists in the sea where sur- 

 vival appears to require the production of vast numbers of offspring. 

 The growing population of the ocean is dependent on microscopic 

 algae which incorporate nutrient materials into foods. In a micro- 

 scopic world, predator and prey species compete by eating smaller or, 

 in some cases, larger organisms. Radioisotopes incorporated into cells 

 of algae or adsorbed on their surfaces appear in the digestive appara- 

 tus of tiny animals that, in turn, are eaten by other predators. Each 

 of the organisms in such a food web has its own distinctive chemical 

 requirements, accepting certain elements and rejecting others. 



How does one measure the abundance of organisms in the ocean? 

 Only a few marine biological groups have been collected and recorded 

 quantitatively, and most of these groups vary in abundance locally 

 and seasonally. It is known that water currents, temperature, and 



