Response to Copper 
Having characterized linear swimming velocities for B. amphitrite nauplii 
under defined conditions, the effects of sublethal levels of copper on swimming 
speeds were investigated. A primary stock solution of 10,000 ppm Cu in 
dilute nitric acid was adjusted to 1-4 ppm secondary stock solutions using 
deionized water. Final test solutions were obtained by serial dilutions with 1 p 
filtered natural seawater at 32-34°/oo. Total copper was determined by heated 
graphite absorption on a HGA-2100 coupled to a Perkin-Elmer 360 atomic 
absorption spectrophotometer. 
Newly hatched B. amphitrite nauplii were exposed to various copper levels 
for 24 hours at 20°C. Replicate samples of nauplii for each exposure level were 
then video taped in a darkened room using the described darkfield 
illumination. Total mortality at 24 hours post-exposure was determined. 
Larvae were not fed during the experiment. Analyses indicated a 3-15 percent 
decrease in total copper occurred during a 24-hour static exposure. In the first 
test, nauplii were exposed to levels ranging from control (3 ppb) to 
approximately 50 ppb Cu (Table 18-3). No increased mortality was observed; 
however, MLV of nauplii exposed to 10 through 47 ppb Cu nearly doubled 
relative to control values. Close agreement was observed in replicate samples. 
In a second test, three higher copper levels were added: 120, 185, 350 ppb. 
After the 24 hour Cu exposure period, nauplii were transferred to clean filtered 
seawater with the mixed algal diet. Significant mortality at 24 hour 
post-expossure occurred only at 350 ppb Cu. However, a delay in molting was 
Table 18-3. Mean Linear Velocities (MLV) of 
Balanus Amphitrite Stage II Nauplii Exposed to Sublethal 
Copper Levels for 24 Hours at 20°C 
Copper 
(ppb) 
No. 
Animals 
Mean Path 
Duration (sec) 
MLV ± sd Mortality 24 Hr. 
(mm/sec) Post Exposure 
3 
16 
6.4 
0.71 ±0.27 
3% 
3 
14 
6.2 
0.65 ± 0.44 
5% 
10 
12 
5.0 
1.24 ±0.48 
4% 
12 
10 
7.3 
1.18 ± 0.51 
2% 
14 
21 
7.6 
1.09 ± 0.54 
2% 
14 
6 
7.3 
1.06 ±0.76 
4% 
30 
10 
7.8 
1.07 ±0.54 
2% 
47 
15 
6.4 
1.25 ± 0.47 
5% 
47 
11 
7.0 
1.16 ±0.48 
5% 
280 
