Publication Date


Document Type


Committee Members

Chad Hammerschmidt (Advisor), Mark McCarthy (Committee Member), Silvia Newell (Committee Member)

Degree Name

Master of Science (MS)


Mercury (Hg) is a volatile element increasing in concentration in the environment as a result of anthropogenic emissions. Microorganisms can transform mercury into monomethylmercury (MMHg), the form of Hg that bioaccumulates, biomagnifies, and can harm humans and wildlife. Most studies of MMHg bioaccumulation in wildlife have focused on aquatic organisms due to consumption of fish being the primary route of human exposure to MMHg. However, organisms in terrestrial ecosystems also are exposed to MMHg that may impact ecosystem biodiversity, food-web dynamics, and organisms and ecosystem health. I investigated bioaccumulation and maternal transfer of MMHg in spotted salamanders (Ambystoma maculatum) captured from two locations in southern Ohio in 2016. Total length, weight, sex, and whole-body concentrations of MMHg were determined for 159 organisms. Spotted salamanders in southern Ohio bioaccumulated MMHg to concentrations (mean = 93 ± 33 ng/g dry wt.) comparable to those is other salamander species in other locations. MMHg concentrations in spotted salamander carcasses were unrelated to organism size. MMHg was maternally transferred to eggs, but concentrations in eggs were not strongly correlated with concentrations in associated maternal carcasses. MMHg concentrations in the distal 4 cm of tail were positively correlated with concentrations in spotted salamander carcasses, which provides a non-destructive sampling method for future screening and biomonitoring MMHg concentrations in these organisms. Due to their ubiquity, spotted salamanders may be useful bioindicators of MMHg bioaccumulation and cycling in forested ecosystems of southern Ohio, and by extension, other terrestrial ecosystems that they inhabit.

Page Count


Department or Program

Department of Earth and Environmental Sciences

Year Degree Awarded