74 



Atomic Radiation and Oceanography and Fisheries 



phenomenon is that in which calcium inhibits 

 the stimulatory action of potassium on heart 

 muscle. 



Third, there may be a synergistic effect of one 

 element on another. Ketchum (1939) has 

 shown that the uptake of phosphorus by marine 

 diatoms was enhanced with increased concen- 

 trations of nitrogen. 



d. Specificity of organisms and tissues for 

 given elements 



The specific activity of a radionuclide in any 



present in the flight muscles of some birds and 

 it has been shown that radiophosphorus is in- 

 corporated into the flight muscles of migratory 

 waterfowl (Krumholz, 1954). 



Although many different kinds of aquatic or- 

 ganisms have the ability to concentrate phos- 

 phorus in their tissues, there are few that show 

 such a specificity for that element as the various 

 plankters. The uptake of phosphorus 32 by 

 plankton algae in a lake has been demonstrated 

 by Coffin and his associates (1949) and others, 



TABLE 4 Approximate Concentration Factors of Different Elements in Members of the Marine 

 Biosphere. The Concentration Factors are Based on a Live Weight Basis. 



Concentration Factors 



Concentration Algae 



Form in in seawater (Non-cal- 



Element Seawater ( micrograms/ 1.) careous) 



Na Ionic 10' 1 



K Ionic 380,000 25 



Cs Ionic 0.5 1 



Ca Ionic 400,000 10 



Sr Ionic 7,000 20 



Zn Ionic 10 100 



Cu Ionic 3 100 



Fe Particulate 10 20,000 



Nil Ionic 2 500 



Mo lonic-Particulate 10 10 



V ? 1 1,000 



Ti ? 1 1,000 



Cr ? 0.05 300 



P Ionic 70 10,000 



S Ionic 900,000 10 



I Ionic 50 10,000 



1 Values from Laevastu and Thompson (1956). 



organism is dependent upon the ability of the 

 organism or any of its parts to concentrate that 

 nuclide. If the stable counterpart of the radio- 

 nuclide does not normally enter into the physio- 

 logical processes of an organism, neither will 

 the radioactive material. 



It is well known that certain tissues have a 

 predilection for concentrating specific elements. 

 For instance, iodine is concentrated in the thy- 

 roid tissue of animals and hence radio-iodine 

 will also be concentrated there. Strontium, like 

 calcium, is a bone seeker and the radioisotopes 

 of both of those elements will be concentrated 

 in the bony skeletons of animals. Similarly, 

 both strontium and calcium are concentrated in 

 certain parts of vascular plants and so are the 

 radioisotopes. Phosphorus is one of the princi- 

 pal constituents of bone and radiophosphorus 

 is also concentrated in that tissue. The com- 

 pound adenosine triphosphate is commonly 



and Whittaker (1953) showed that phyto- 

 plankters from the Columbia River concentrated 

 radiophosphorus by factors as great as 300,000. 

 Krumholz (1954, 1956) found that attached 

 fresh-water algae (Spirogyra) concentrated ra- 

 diophosphorus by a factor of 850,000, and that 

 many fresh-water zooplankters concentrated that 

 radionuclide by factors of more than 100,000. 

 Approximate concentration factors for marine 

 organisms are given in Table 4. 



e. Osmotic and ionic regulation 



Osmotic and ionic regulation are known to 

 occur in a variety of ways. The usual pathways 

 of excretion are through the urine, feces, skin, 

 respiration, and particle ejection, and the 

 method of excretion depends upon the particu- 

 lar organism and element involved. Ionic regu- 

 lation may also occur by way of the chloride 

 secreting cells in the gills of those fishes that 

 migrate from salt to brackish water (Keys, 



