3.7 Seaweed and Sediments (Topinka, Bigelow Laboratory for Ocean 

 Sciences) 



In support of an investigation on the impact of the spill on 

 macroalgal population recovery and growth, a series of plant and 

 adjacent sediment samples was analyzed by GC to determine if and to 

 what extent AMOCO oil was associated with the plants (Table 27). 



The data presented in Table 28 in conjunction with a consideration 

 of Figures 3.81 and 3.82 illustrate that while several of the plant 

 samples do contain weathered oil (see Fig. 3.81) the n-alkane, penta- 

 decane (n-C^) , is the most abundant biogenic component in all sam- 

 ples. The distribution of biogenic components in general (Fig. 3.82) 

 can be seen as contributing markedly to the total hydrocarbon levels 

 even in the "oil-impacted" tissues. 



GC/MS results of an "oil impacted" plant's aromatic hydrocarbon 

 fraction (Table 29) indicate that again the P and DBT family series are 

 the most abundant aromatic compounds present. In this sample the P 

 compounds are, in total, more abundant than the DBT series, but the 

 C3DBT are still the most abundant group (8400 ppb) . 



TABLE 27. AMOCO CADIZ chemistry program; seaweed samples (Topinka). 



Frequency 



June 1979 15 Plant + 7 Sediment 

 August 1979 2 Plant 

 May 1980 3 Plant 



Summer 1980 12 Plant 



TOTAL 32 



Locations 

 Var ious 



GC/MS 



One Seaweed Sample 



94 



