Heavy Metals Effect on the Fertilization and Development of Sea Urchin Embryos

Heavy metal pollution is a prevalent threat in aquatic systems, particularly in coastal regions where coast-side industries or large tributaries carrying pollutants introduce these toxins into the environment, necessitating bioindicators such as sea urchins to ascertain the toxicity of contaminants in the environment. In this experiment, sea urchins were used to test the effects of copper and zinc heavy metals on development. Concentrations of 8 ug/L, 24 ug/L, and 40 ug/L of copper and 40 ug/L, 400 ug/L, and 4,000 ug/L of zinc were used to examine the effects of these heavy metals on both fertilization and subsequent development over the next 72 hours. Data was recorded on the number of abnormalities and deaths compared to the total number of embryos for both copper and zinc. Copper was shown to cause a slight inhibition of fertilization at high concentrations and embryo development was impaired in its ability to form the vegetal plate as a blastula and its capacity for convergent extension in gastrulation. Zinc’s affects were more dramatic, causing 100% death in the highest concentration of 4,000 ug/L and relatively low survivorship in the other two concentrations as well as abnormalities in blastopore formation and larval development. Copper was concluded to have a more toxic effect on development of embryos at a lower concentration, but less of an effect on the overall survivorship of the embryos.