• Snodgrass, J., C. Jagoe, A.L. Bryan, H. Brant, and J. Burger. 2000. Effects of trophic status and wetland morphology, hydroperiod, and water chemistry on mercury concentrations in fish. Can. J. Fish. Aquat. Sci. 57:10.

• Amphibians in short hydroperiod wetlands had more Hg • Tadpoles had more Hg than salamander larvae, perhaps due to feeding near

sediments

THE EFFECT OF WETLAND HYDROPERIOD AND FEEDING ECOLOGY ON AMPHIBIAN MERCURY CONCENTRATIONS

Carlos Tapia Stacey Lance, David Scott, Megan Winzeler, Austin Coleman, Paul Walkup

Savannah River Ecology Laboratory, University of Georgia

• Determine the effect of hydroperiod length on amphibian mercury (Hg) levels

• Determine species-specific differences and effect of trophic status on Hg uptake

Predictions • Amphibians in short hydroperiod

wetlands will have more Hg accumulation

• Salamander larvae will take in more Hg than anuran larvae

• Large amounts of atmospheric mercury (Hg) are deposited in wetlands

• Hg is a neurotoxin, and can affect individual, population and ecosystem health

• Previous studies show that hydroperiod and trophic status have effects on Hg levels in fish

• Amphibians can be both predator and prey

• Tadpoles are herbivorous, whereas salamander larvae are carnivorous

Methods

1. Dip-netting • Sampled 25 wetlands

with varying hydroperiods

• Used nets to catch larvae

• Brought them to the lab for processing

2. Freeze-Drying • Samples measured and

weighed

• Freeze dried to constant weight

4. Hg Analysis • Run on DMA 80 Milestone

Hg Analyzer

• Uses thermal decomposition, amalgamation and atomic absorption spectrophotometry

3. Homogenizing • New method created for

homogenizing

• Samples grounded with a coffee grinder

• Homogenized further by using a bead-beater device

Objectives

Background

• Tadpoles had a significantly higher Hg level than salamanders (Figure 1)

• Larvae from short hydroperiod wetlands also had a higher Hg level than in long hydroperiod wetlands (Figures 1, 2, & 3)

• Young-of-year mole salamander larvae have less Hg than older paedomorphs (Figure 4)

Results

Conclusions References

A. Dip-Netting B. Tree frog caught with dip-netting C. Freeze-drier D. Coffee grinder E. Putting ground samples in tubes F. Hg analyzer G. Bead Beater

A

B

C

D E

F G

Top: Mole salamander (Ambystoma talpoideum) Middle: Marbled salamander (A. opacum) Bottom: Southern leopard frog (Lithobates sphenocephalus)

1

2 3

4

1. Whole body Hg concentrations by species and hydroperiod. 2. Hg differences across wetland drying scores for A. opacum. 3. Hg differences across wetland drying scores for L.

sphenocephalus. 4. A. talpoideum Hg concentrations by life stage.

I would like to thank the National Science Foundation for funding the REU program, Melissa Pilgrim and J. Vaun McAurthur, for running the program, and the Department of Energy for allowing us to use the Savannah River Site