SREL Reprint #3224

Effects of Chronic Copper Exposure on Development and Survival in the Southern Leopard Frog (Lithobates [Rana] sphenocephalus)

Stacey L. Lance, Matthew R. Erickson, R. Wesley Flynn, Gary L. Mills, Tracey D. Tuberville,
and David E. Scott

Savannah River Ecology Laboratory, University of Georgia, Aiken, South Carolina, USA

Abstract: Exposure to environmental contaminants contributes to the global decline of amphibian populations. The impacts of organic contaminants on amphibians are well documented. However, substantially less is known concerning the potential effects of metals on amphibian populations. Copper (Cu) is an essential element, but it can be toxic at concentrations only slightly higher than the normal physiological range. The present study examines the effects of chronic Cu exposure on embryos and larvae of southern leopard frogs, Lithobates (Rana) sphenocephalus. Groups of eggs frommultiple clutches were collected fromtwo wetlands and exposed to a range of Cu concentrations (0–150µg/L) until they reached the free-swimming stage, and then individual larvae were reared to metamorphosis. Higher Cu concentrations significantly reduced embryo survival to the free-swimming stage but did not further reduce survival to metamorphosis. Larval period was affected by Cu treatment, but the clutch from which larvae originated (i.e., parentage) explained a higher proportion of the variation. Embryo survival to hatching varied significantly among clutches, ranging from 42.9 to 79.2%. Measurable levels of Cu were found in larvae with body burdens up to 595µg Cu/g dry mass in the 100µg/L treatment, and larval Cu body burdens were higher than in metamorphs. The present study also demonstrated that higher initial egg density ameliorated embryo mortality at higher Cu levels and should be accounted for in future studies.

Keywords: Lithobates (Rana) sphenocephalus, Copper, Amphibian, Ecotoxicology, Metal toxicity

SREL Reprint #3224

Lance, S. L., M. R. Erickson, R. W. Flynn, G. L. Mills, T. D. Tuberville, and D. E. Scott. 2012. Effects of Chronic Copper Exposure on Development and Survival in the Southern Leopard Frog (Lithobates [Rana] sphenocephalus). Environmental Toxicology and Chemistry 31(7): 1587-1594.

This information was provided by the University of Georgia's Savannah River Ecology Laboratory (srel.uga.edu).