Project: Collaborative Research: Defining the Role of Biologically Produced Reactive Oxygen Species in Dark Mercury Cycling

NSF Abstract:

Mercury (Hg) is a toxic trace element that bioaccumulates into marine food webs, imposing a health threat to humans through the consumption of seafood. However, controls on the cycling of Hg in the ocean are poorly understood. Most research to date has focused on sun-lit and/or Hg-laden environments, where light-induced chemical and mercury resistance reactions, respectively, have been identified as dominant pathways for Hg cycling. The paradigm that dark Hg reactions are irrelevant is fading and it is now apparent that dark redox reactions, both reduction and oxidation, are important in the cycling of Hg. In this study, researchers at the Woods Hole Oceanographic Institution and Colorado School of Mines will obtain a better understanding of the biogeochemical reactions responsible for dark redox transformations of mercury (Hg) in marine systems. The researchers will explore the relationship between microbial activity, reactive oxygen species, and Hg speciation in a series of laboratory- and field-based investigations to obtain a mechanistic understanding of dark Hg cycling. By identifying new controls on the redox cycling of Hg in the ocean, this research will help inform global and ecosystem models used to predict Hg bioavailability.

Broader Impacts: The proponents plan to educate high school teachers from Boston Green Academy in South Boston on mercury biogeochemistry and have one teacher participate in the summer research cruises, as well as develop science curricula to engage the underrepresented students at the school in science. One postdoc and one graduate student from Woods Hole Oceanographic Institution and one graduate student from the Colorado School of Mines would be supported and trained as part of this project. It is anticipated that undergraduate students would have the opportunity to participate in the study as summer interns.