Flipping through field notebooks…
The western United States (U.S.) is experiencing severe drought conditions exacerbated by climate change. As annual precipitation and runoff generation decline, American beaver (Castor canadensis) populations are increasing, in part due to reintroduction efforts aimed at restoring water resources. With time beaver institute a pattern of dam building and abandonment that drastically influence the river corridor through alterations to the geomorphology and the biogeochemistry. Beaver dams have variable impacts on the production of methylmercury (MeHg), a neurotoxin that can bioaccumulate and biomagnify with successive trophic levels. Methylation is driven by myriad biogeochemical processes that are mediated by geomorphic processes and the physical template. Previous work has demonstrated that beaver ponds create conditions for methylation, the rate of which fluctuates throughout the year (Roy et al., 2009a; Roy et al., 2009b). In Summer 2024, I will collect samples to quantify total mercury (THg), MeHg, sulfate (SO42-) reduction rates (SRR), methylation and demethylation rates, among other biogeochemical measurements in sediment, surface, and porewater. Together, the data will reveal the dominant mechanisms within differently aged beaver ponds throughout the year that drive the production and export of MeHg, providing information to stakeholders about the implications beaver have for water quality. Effectively communicating science to the community that uses the resource under investigation is crucial. Final steps will include making CZ case studies that can be used by the geoscience community for undergraduate teaching and to present to the community that the research was conducted in.