Total mercury, methylmercury, and isotopic composition in various life stages of boreal chorus frogs (Pseudacris maculata) at two subalpine ponds in the Rocky Mountains, CO, USA, 2015
Dates
Publication Date
2023-02-22
Start Date
2015-05-25
End Date
2015-09-04
Citation
Rowland, F.E., Muths, E.M., Eagles-Smith, C.A., Stricker,C.A., Kraus, J.M., Harrington, R.A., and Walters, D.M., 2022, Total mercury, methylmercury, and isotopic composition in various life stages of boreal chorus frogs (Pseudacris maculata) at two subalpine ponds in the Rocky Mountains, CO, USA, 2015: U. S. Geological Survey data release, https://doi.org/10.5066/P928IIOS.
Summary
Mercury is an atmospherically transported contaminant found even in relatively pristine habitats. Once accumulated at the base of the food web, mercury can move between animals that are linked trophically. Pond-breeding amphibians may be particularly important vectors of mercury flux from remote freshwater to terrestrial systems because they feed on algae and detritus as tadpoles and metamorphose into insectivorous terrestrial adults where they carry out most of their remaining life cycle. However, it is still unclear how mercury concentrations change across life stages in complex life cycle amphibian species. The data presented here includes total mercury (THg), methylmercury (MeHg), and isotopic composition (δ13C, δ15N) in boreal [...]
Summary
Mercury is an atmospherically transported contaminant found even in relatively pristine habitats. Once accumulated at the base of the food web, mercury can move between animals that are linked trophically. Pond-breeding amphibians may be particularly important vectors of mercury flux from remote freshwater to terrestrial systems because they feed on algae and detritus as tadpoles and metamorphose into insectivorous terrestrial adults where they carry out most of their remaining life cycle. However, it is still unclear how mercury concentrations change across life stages in complex life cycle amphibian species. The data presented here includes total mercury (THg), methylmercury (MeHg), and isotopic composition (δ13C, δ15N) in boreal chorus frogs (Pseudacris maculata) at two subalpine ponds in the Rocky Mountains, CO, USA. We sampled various life stages including breeding adults, eggs, tadpoles, metamorphs, and mid-summer adults.
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Related External Resources
Type: Related Primary Publication
Rowland, F.E., Muths, E., Eagles-Smith, C.A., Stricker, C.A., Kraus, J.M., Harrington, R.A., and Walters, D.M., 2023, Complex Life Histories Alter Patterns of Mercury Exposure and Accumulation in a Pond-Breeding Amphibian: Environmental Science & Technology, https://doi.org/10.1021/acs.est.2c04896.
Aquatic systems are hotspots of inorganic mercury methylation. We investigated how mercury concentrations change across vertebrate complex life cycles. We found large differences in Methyl Mercury concentrations and percent Methyl Mercury among life stages as a function of minimal maternal transfer to eggs, diet switching, and large loss of body mass (i.e., catabolism) during metamorphosis and hibernation. Breeding adults had the highest mean Methyl Mercury concentration, but concentrations in eggs were minimal. Concentrations remained low in tadpoles but doubled at metamorphosis. Isotopic signatures also changed substantially among egg, tadpole, and metamorphic life stages. Importantly however, isotopic signatures did not always align with mercury dynamics. We show that transitions among life stages in animals that undergo metamorphosis are an important component of environmental exposure to contaminants, and that biological processes such as catabolism can alter typical trajectories of trophic transfer and accumulation of contaminants such as mercury. Researchers often use contaminants and isotopes in food webs interchangeably, but although diet is an important determinant of mercury accumulation and exposure, we found life cycle events also strongly alter mercury concentrations.
