Oil Spill Effects 399 



quantities of oil were shaken with Pond C water, the short-term 

 productivity was reduced by 50% (by 15 ^1 oil liter"') and stopped 

 completely by 30 nl. Oil layered on top of experimental vessels and not 

 shaken was only half as toxic. Thus, the water-soluble fraction of the oil is 

 inhibitory to the algae. 



The inhibition lasts at least several weeks (Figure 9-7) but the algae 

 begin to recover after one week. This inhibition and recovery has also been 



100 



1970 



« 



M 



O 



E 

 o 



u 



Q. 



100 



80 



60 



40 



20- 



_ Pond C 



80 

 60 

 40 

 20 



Chryso 



.Helero 



— r~ 



1971 



FIGURE 9-8. Groups of phytoplankton as a percentage 

 of the total wet weight in Ponds C and E. 



