CAREER: Uncovering the Geochemical and Biomineralization Processes Responsible for Mercury-Selenium Antagonism in the Environment

The investigator and his research group at the University of California Davis will study how interactions between mercury and selenium influence the cycling and bioaccumulation of mercury in the environment. Mercury is a prevalent global contaminant that impacts both environmental and human health worldwide. The research of this project aims to fill critical knowledge gaps in our understanding of mercury-selenium interactions, which will permit improved management of complex freshwater environments and accurate risk assessment of mercury to wildlife and humans.

Beyond research, the investigator will work to broaden public interest in metal contaminants through citizen science at U.S. national parks and develop new undergraduate curriculum with project data. The educational materials developed will be published on a public digital library for educators.

Three research hypotheses will be pursued to establish the mechanisms by which selenium influences the methylation of mercury, the uptake of neurotoxic methylmercury in food webs, and the biomineralization of methylmercury to mercury selenide. Natural lakes with defined inputs of mercury and selenium will be used for field sampling and experimentation.

A suite of interdisciplinary atomic- and molecular-level techniques will be used, including microbial genomics, X-ray absorption spectroscopy, and protein purification. These methods will be applied on sediments, within components of food webs, and with purified protein to investigate the underlying geochemical and biomineralization reactions responsible for mercury-selenium antagonism in the environment.

Undergraduate, graduate, and postdoctoral researchers will cross-train with collaborators within and outside the university, co-convene sessions at conferences, and co-develop problem-based learning activities for the classroom and educational materials for the public. These efforts aim to develop a diverse and globally competitive STEM workforce to address future environmental challenges beyond the topic of mercury-selenium antagonism.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.