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Vol. 53 - Alaska Resources Library and Information Services

Vol. 53 - Alaska Resources Library and Information Services

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In clams collected immediately before the BIOS oil spills, concentrations of<br />

several tissue free amino acids were significantly different in clams from the four bays<br />

(Table 4.3). The mean concentration of 6 free amino acids was significantly different in<br />

clams from the reference bay (Bay 7) <strong>and</strong> Bay 9, while concentrations of only two amino<br />

acids in clams from Bays 10 <strong>and</strong> 11 were significantly different from those of clams from<br />

the reference bay. Immediately after the spills, concentrations of 1-3 amino acids were<br />

significantly different in clams from the reference bay <strong>and</strong> from the three bays receiving<br />

dispersed or undispersed crude oil (Table 4.4). Concentrations of total <strong>and</strong> most individual<br />

tissue free amino acids were lower in clams from the most heavily contaminated bay (Bay<br />

10) than in clams from the other two bays receiving oil <strong>and</strong> the reference bay. In clams<br />

collected during the second post-spill sampling approximately 2 weeks after the spills,<br />

there were many statistically significant differences in concentrations of individual tissue<br />

free amino acids among clams from the four bays (Table 4.5). Values for clams from Bay<br />

10 (the most heavily contaminated bay) varied most from the corresponding values for<br />

clams from the other three bays.<br />

Two parameters which have been recommended as indices of sublethal stress<br />

in marine invertebrates are the molar ratio of taurine to glycine <strong>and</strong> the sum of the<br />

concentrations of threonine plus serine. Stressed animals should have a higher<br />

taurine/glycine ratio <strong>and</strong> lower threonine plus serine concentration than unstressed<br />

animals. The only oil-exposed group of clams with taurine/glycine ratio <strong>and</strong> threonine<br />

plus serine concentration significantly different from that of clams from the reference<br />

bay was that from the most heavily contaminated bay (Bay 10) collected during the<br />

second post-spill sampling (Table 4.6). Taurine/glycine ratio was elevated <strong>and</strong> threonine<br />

plus serine concentration was depressed relative to reference animals.<br />

Spearman rank correlation tests were performed on all biochemical<br />

parameters measured for clams from the three sampling times <strong>and</strong> four experimental<br />

bays. Parameters which showed a high ([alpha]

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