The microbial hydrocarbon biodegradation potential measurements 

 showed that following the AMOCO CADIZ oil spillage, indigenous microbial 

 populations in the sediment at all sampling sites were capable of 

 degrading both aliphatic and aromatic components of crude oil (Tables 

 4-8). The variability in the results is not indicated in these tables, 

 but the standard error was less than 4% for the percentage degraded and 

 less than 10% for the percentage mineralized in all cases. The 

 biodegradation potentials indicated that n-alkanes were preferentially 

 degraded and that pristane was degraded at approximately half the rate 

 of n-hexadecane. For aliphatic hydrocarbons approximately 30% of the 

 amount of hydrocarbon biodegraded was converted to C0„ (mineralized) . 

 Methodological difficulties in handling naphthalene made it difficult to 

 assess the true extent of biodegradation for this compound. It is 

 apparent, though, that the indigenous microbial populations were capable 

 of degrading light aromatic hydrocarbons. The rates of degradation of 

 the 3- and 4-ringed polynuclear aromatic hydrocarbons were lower than 

 for branched and straight chained aliphatic hydrocarbons. In the case 

 of the polynuclear aromatic hydrocarbons, a very low proportion of the 

 amount of hydrocarbon degraded was converted to CO . 



TABLE 4. Hexadecane biodegradation showing % degraded and 

 (% mineralized). 



Site 12-78 3-79 8-79 11-79 3-80 7-80 6-81 



1 40 41 21 17 10 25 17 



10 



