Research

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Human activities have resulted in the release and perturbation of metal contaminants and have disrupted other element cycles that influence metals. Our research covers a variety of topics on metal contaminants, with a focus on the metal mercury (Hg). The overarching theme of our research is to address the scientific needs to advance understanding and propel mitigation of metal exposure in both man-made and natural environments. Active areas of research include:

 

Mechanisms of Mercury-Selenium Interactions in the Environment

 

Summary: The uptake of mercury in aquatic food webs is known to be influenced by interactions between mercury and selenium, generally termed “mercury-selenium antagonism”. This project aims to establish the mechanisms by which selenium influences the formation of toxic methylmercury, the uptake of methylmercury in biota, and the biomineralization of methylmercury to mercury selenide in higher organisms. The results are anticipated to permit improved management of complex freshwater environments and accurate risk assessment of mercury to wildlife and humans.

Project MembersBen Peterson

Collaborations: Alain Manceau (Univ. Grenoble Alpes); Sarah Janssen and Collin Eagles-Smith (U.S. Geological Survey); Heidi Goenaga-Infante (LGC Group, UK); Michelle Villegas-Frazier (UC Davis Native American Academic Student Success Center).

Funding Source: NSF Geobiology and Low Temperature Geochemistry Program (EAR-2143243)

Hg Se interactions
Research questions (Q1-Q3) on Hg-Se interactions. (credit: Brett Poulin)

 

Sulfur, Carbon, and Mercury Dynamics in Subtropical Wetlands

 

Summary: Water quality remains one of the biggest issues facing the restoration of the Florida Everglades, an iconic ecosystem of subtropical wetlands. The Florida Everglades receive pressure from land use / water management decisions and from sea-level rise. This research project aims to provide the science to understand how internal drivers (e.g., water management or ecosystem restoration efforts) versus external drivers (e.g., sea-level rise) impact the cycling of sulfur, carbon, and mercury in the greater Everglades ecosystem. The goal is to improve the ability to predict the biogeochemical responses of the Florida Everglades to land and water management efforts and sea-level rise.

Project Members: Bryce Cook, Ben Peterson

Collaborations: Dave Krabbenhoft, Sarah Janssen, and Bill Orem (U.S. Geological Survey)

Funding Sources and Support: U.S. Geological Survey Priority Ecosystems Sciences Program, NSF Geobiology and Low Temperature Geochemistry Program (EAR-1629698).

Mercury cycling in the Florida Everglades (credit: Brett Poulin)
Mercury cycling in the Florida Everglades (credit: Brett Poulin)

 

Remediation of Arid-Land Reservoirs

 

Summary: For much of the Western U.S., surface water is scarce and often present as large water-supply or hydroelectric reservoirs. Improving the management of these systems is critical to addressing their negative ecologic impacts while meeting energy and water resource needs. The goals of this project are to provide the science to support the improved management of arid-land reservoirs to mitigate the uptake of mercury in aquatic food webs and releases of methylmercury in outflow waters.

Project Members: Virginia Krause

Collaborations: Dave Krabbenhoft, Austin Baldwin, and Collin Eagles-Smith (U.S. Geological Survey); Jesse Naymik (Idaho Power Company); Reed Harris (Reed Harris Environmental Ltd.).

Funding Sources: Idaho Power Company, U.S. Geological Survey Environmental Health Program

HCC photo
Hells Canyon Reservoir, Idaho (credit: Brett Poulin)

 

Fate of Permafrost Mercury and Carbon in Arctic Landscapes

 

Summary: Permafrost soils of the Arctic contain large stores of ancient mercury that are being released to freshwater and coastal marine environments from thawing soils due to a warming Arctic. The central questions surrounding mercury in the Arctic are the relative importance of ancient mercury released from thawing permafrost soils versus newer mercury from the atmosphere, and how rapidly changing conditions in Arctic landscapes will affect the transformations and food web uptake of these different sources of mercury. To address these questions, this study uses multiple approaches to track the releases, transformations, and uptake of both carbon and mercury from permafrost soils to aquatic ecosystems and subsequently to resident fish in northwest Alaska.

Project Members: Ben Peterson, Jeff Murray

Collaborations: Elchin Jafarov (Woodwell Climate Research Center); Sarah Janssen, Michael Carey, and Josh Koch (U.S. Geological Survey); Jon O’Donnell and Nina Chambers (U.S. National Park Service); Michelle Villegas-Frazier (UC Davis Native American Academic Student Success Center); 

Funding Source: NSF Arctic Natural Sciences Program (ANS-2211426)

Eli River Beaver Pond, Noatak Nat. Preserve Alaska (credit: Brett Poulin)
Eli River Beaver Pond, Noatak Nat. Preserve Alaska (credit: Brett Poulin)

 

Toxic Metal Releases in E-cigarette Aerosols

 

Summary: Electronic cigarettes have gained worldwide popularity as an alternative to traditional cigarettes, particularly among adolescence. Yet, the factors governing the releases of metals in e-cigarette aerosols is poorly characterized. This research aims to profile the operational factors influencing the release of toxic metals in e-cigarette aerosols.

Collaborations: Tran Nguyen (project PI), Kent Pinkerton (co-PI), and Amy Madl (UC Davis)

Funding Source: University of California Tobacco-Related Disease Research Program