Physiological responses of the subtidal prosobranch, Babylonia lutosa (Gastropoda: Buccinidae), to copper

Two size groups (mean shell lengths of 26.33 mm and 53.60 mm) of the subtidal prosobranch gastropod, Babylonia lutosa, were exposed to three sublethal concentrations of copper (0.02, 0.06 and 0.20 ppm) plus a control for 23 days. The oxygen consumption rate and the ammonia excretion rate were measured weekly and the O:N ratio was computed from these two physiological rates. Effects of copper on the two size groups were similar. The oxygen consumption rate, ammonia excretion rate and O:N ratio changed significantly with the interaction between concentration of copper and time. Both the oxygen consumption rate and the ammonia excretion rate decreased when the concentration of copper and the time of the experiment increased while values of O:N ratio remained low (~ 10-35) for all groups (except for 0.20 ppm Cu on day 2) throughout the experiment. The results showed that the oxygen consumption and the ammonia excretion were sensitive and reliable indices for monitoring the impact of copper.