Abstract

Title: Toxicity of Copper on Acropora cervicornis: The effect of a lethal reference toxicant on an endangered coral

Coral reefs play an important role in marine ecosystems; protecting coastlines from flooding, and supporting more species per unit than any other marine ecosystem. But, coral reefs are in danger because of environmental pollutants that seep into the oceans, including elemental copper. The purpose of my research was to discover the LC-50 and the EC-50 of copper chloride for Acropora cervicornis, an endangered species of coral, after 54 hours.

In order to calculate the lethal and sublethal concentrations of copper on Acropora cervicornis, I used a semi-quantitative scoring matrix to assess the sublethal stress of the copper for 6 increasing concentrations of copper chloride. There were 35 dosing vessels, and 5 fragments of coral for each concentration. I scored the individual coral fragments 3 times, every 24 hours, based on their color, polyp retraction, tissue attenuation, mucus produced, and mortality. I used a scale from 0 (normal limits) to 3 (severely affected) with a precision level of 0.5.

After taking data points, I found the average score at each concentration for each physical characteristic after 54 hours. I graphed my data using Logger Pro, and found the logarithmic line of best fit for each diagnostic criteria. The LC-50 was .0327 mg/L, and the average EC-50 was .0170 mg/L.

The lethal concentration is .0327 mg/L after 54 hours, and the concentration of copper in the oceans right now is .09 mg/L, which is 3x greater. This will, and is, leading to extinction of the Acropora cervicornis.