118.4 Saturday, Jan. 7 The Lethal and Sublethal Consequences of Copper Exposure For Lithobates sphenocephalus and Gastrophryne carolinensis FLYNN, R.W.*; KUHNE, W.W.; SCOTT, D.E.; ERICKSON, M.R.; MILLS, G.L.; TUBERVILLE, T.D.; LANCE, S.L.; Univ. of Georgia, Savannah River Ecology Laboratory; Savannah River National Laboratory; UGA-SREL; UGA-SREL; UGA-SREL; UGA-SREL; UGA-SREL email@example.com
Exposure to environmental contaminants is one of the many documented causes of global amphibian population declines. Contamination of aquatic habitats with heavy metals is an increasingly common and pernicious problem for amphibians. Copper (Cu) is an essential trace element that is ubiquitous in nature and toxic to organisms at levels only slightly more than those needed for normal physiological function. We conducted a series of laboratory trials to investigate the effects of Cu exposure on Lithobates sphenocephalus and Gastrophryne carolinensis at environmentally relevant concentrations. We found significantly different susceptibilities to Cu at the individual, population, and species levels. For L. sphenocephalus, survivorship from the egg stage to metamorphosis is significantly reduced by exposure to >50 ppb Cu. In addition, egg/larval success differed among clutches, and both source of clutch and Cu treatment directly affected larval period. G. carolinensis embryos are substantially more sensitive to Cu than L. sphenocephalus, with levels as low as 15 ppb significantly reducing egg survival. To further examine impacts on G. carolinensis we assessed the effects of Cu level on embryonic developmental rate from fertilization to free swimming. We demonstrate that Cu exposure significantly delays development. Under natural conditions delayed development can be an important sublethal effect that increases larval susceptibility to predation, decreases competitive ability, and reduces the likelihood of reaching metamorphosis during short hydroperiod years. Overall, copper significantly affects amphibian larvae and chronic exposure may alter important population processes.