THE EFFECT OF AMMONIUM NITRATE SOLUTIONS ON SOME ASPECTS OF THE BIOLOGY OF THE BLACK MUSSEL, CHOROMYTILUS MERIDIONALIS

Summary

The effects of low concentrations of ammonium nitrate on the fertilization and early development of Choromytilus meridionalis have been studied in the laboratory at 14°C. Concentrations up to 10 p.p.m. have no significant effect on fertilization, though concentrations as low as 0,5 p.p.m. retard early development. Spontaneous recovery takes place unless the pollutant is repeatedly renewed. At 10 p.p.m. a high proportion of the larvae achieving the veliger stage show abnormal shell growth. At 100 p.p.m. ammonium nitrate there is complete failure to pass beyond the trochophore stage, development tending to terminate at gastrulation. These results contrast with the tolerance of the adults, solutions of 1 000 p.p.m. having no significant effect on either the tendency to shell adduction or the ciliary beat of the gills.