Meeting Abstract
118.3 Saturday, Jan. 7 Chronic copper exposure in southern toads, Anaxyrus terrestris: lethal, sublethal, and gene expression effects LANCE, S.L.*; JONES, K.L.; FLYNN, R.W.; ERICKSON, M.R.; TUBERVILLE, T.D.; SCOTT, D.E.; Savannah River Ecology Laboratory, University of Georgia; University of Colorado School of Medicine; Savannah River Ecology Laboratory, University of Georgia; Savannah River Ecology Laboratory, University of Georgia; Savannah River Ecology Laboratory, University of Georgia; Savannah River Ecology Laboratory, University of Georgia lance@srel.edu
Chronic exposure to environmental contaminants can cause effects at higher levels of biological organization such as populations and communities. However, due to inherent challenges in assessing these impacts most studies focus on individual survivorship under acute exposure. To assess the long-term effects of contaminant exposure it is critical to examine sub-lethal endpoints, and the potential for organisms to adapt to contaminated environments. We investigated the relevance of sub-lethal endpoints in southern toads, Anaxyrus terrestris, exposed to a range of copper concentrations. We examined several endpoints including hatching success, survival to metamorphosis, time to- and size at metamorphosis. Overall copper significantly reduced survival through the egg and larval stages. We examined eggs from multiple clutches and source populations and both factors were also significant sources of variation in survival. Depending upon the source population survival to the free-swimming stage was significantly reduced at concentrations as low as 10ppb and no larvae reached metamorphosis at concentrations above 15ppb. To better understand the effects of copper we used RNASeq to examine gene expression patterns in developing toads. We compared expression in early development of eggs from 24 to 54 hours post copper treatment. At 55 hours nearly 200 genes were differentially expressed between control and treatment individuals. We discuss our findings and relate them to potential impacts on population level processes.
