MARIN] NANTS 



control authorities with the informa- 

 tion that will enable them to evalu- 

 ate whether removal of floating oil 

 through causing it to sink to the 

 bottom is economically preferable to 

 attempting to collect it on the surface, 

 to speed its natural removal by 

 spreading emulsifying agents, or let- 

 ting it drift ashore. 



The observation of Horn, Teal, and 

 Backus that barnacles thrive attached 

 to floating petroleum lumps and that 

 a pelagic isopod preferentially asso- 

 ciates itself with the same items sug- 

 gests that the components of such 

 lumps are not toxic to these groups 

 of Crustacea. It is generally supposed 

 that the lower-molecular-weight con- 



stituents of petroleum are more toxic 

 than those of higher molecular weight. 

 It is also true that the vapor pressure 

 and solubility in water of these con- 

 stituents both decrease markedly with 

 increasing molecular weight. It seems 

 likely, therefore, that natural proc- 

 esses in the ocean may act rather 

 rapidly in the case of floating petro- 

 leum residues to leave only the more 

 inert, heavier fractions at the sea 

 surface, the lighter fractions having 

 been either volatilized to the atmos- 

 phere or dissolved in the mixed layer 

 of the ocean above the thermocline. 

 Some direct observations of the 

 change in composition with time of 

 floating oil spill seem highly desirable 

 in this regard. 



Horn and his colleague;: further 

 suggest that toxic petroleum co 

 nents find their way into the food 

 chain through fish like the saury, 

 which appear to be voracious feeders 

 of anything they may encounter at 

 the sea surface. It would appear to 

 be relatively easy to sample saury 

 from the catches of the wide-ranging 

 Japanese fishing industry, as well 

 as apex predators such as dolphin 

 (Coryphaena), swordfish, and tuna, 

 to determine if, in fact, any accu- 

 mulation of undesirable compounds 

 originating in petroleum can be de- 

 tected. Porpoises, also mentioned by 

 Horn, can be readily sampled through 

 the individuals that are captured acci- 

 dentally in tuna-seining operations. 



363 



