Mercury Cycling and Effects on Ecological Communities

Science Center Objects

Mercury contamination is a serious issue that impacts both ecosystem and human health on a global scale. In its organic (methylmercury) form, mercury is highly bioaccumulative and is among the most toxic compounds commonly found in the environment. Mercury is a relatively distinctive contaminant in the sense that the risk of deleterious environmental effects is more strongly related to ecological factors that control its cycling than to its inputs and sources.

Thus, even with limited inorganic mercury loading, an ecosystem can suffer serious harmful impacts. The ecological risk of mercury toxicity is directly related to the production of the bioaccumulative and toxic form, methylmercury, which is driven by specific biogeochemical parameters. Importantly, those parameters are directly linked to landscape scale factors such as land use, landscape disturbance, habitat type, water inundation and wetting and drying cycles, organic carbon and nutrient cycling, and inputs from upland terrestrial habitats. Bioaccumulation is driven by population dynamics, habitat use, and food-web structure.

The Contaminant Ecology Research Program (CERP) at the USGS Forest and Rangeland Ecosystem Science Center in Corvallis, Oregon is actively engaged in a broad suite of ongoing mercury studies across the western United States, with a strong focus on habitats and locations within the Pacific Northwest. Our research focuses on two primary themes: (1) landscape and food web factors that influence mercury bioaccumulation and (2) the effects of mercury exposure on vertebrate physiology, behavior, and reproduction. Within those themes some of our active research includes studies about mercury bioaccumulation in wetland habitats and the influence of different wetland management practices on controlling mercury risk; mercury bioaccumulation in food webs of high-elevation lakes on public (National Park Service and U.S. Forest Service) lands; the impacts of non-native fish introductions to food-web energetics and mercury exposure in native amphibians; the role and impact of timber harvest on mercury cycling and bioavailability in the Pacific Northwest; the role of seabirds as vectors of marine-derived mercury to freshwater lakes in oceanic islands; the spatial extent of legacy mining impacts on downstream mercury bioaccumulation, and mercury exposure and associated physiological responses in songbirds, shorebirds, and piscivorous birds across a gradient of habitat types.

Additionally, USGS FRESC is currently leading a new collaborative initiative to synthesize the landscape and climate influences on mercury distribution, cycling, and bioaccumulation across western North America. This initiative involves dozens of scientists from federal and state agencies, academic institutions, and non-profit organizations.

Active Projects

  • Western North America Mercury Synthesis: A Landscape-Scale Analysis of Mercury Cycling, Bioaccumulation, and Risk Linking Long-term Datasets
  • Effects of Non-native Fishes on Mercury Bioaccumulation and Risk to Pond-breeding Salamanders in Olympic National Park
  • Experimental Control of Methylmercury in Rice Wetlands Using Alternative Rice Harvest Practices
  • Forestry Effects on Mercury Cycling and Bioaccumulation at a Watershed Scale
  • Incorporating Wildlife Mercury Exposure and Risk Estimates Using Biomagnification Factors into BOG California Lake Monitoring
  • Mercury Bioaccumulation in Fish from High-Elevation Lakes in National Parks across the Western United States
  • Mercury Bioaccumulation in Terrestrial Songbirds and the Influence of Aquatic Energy Subsidies
  • Mercury Bioaccumulation in Waterbodies of the Wallowa-Whitman National Forest
  • Mercury Contamination in Waterbird Eggs and Risk to Avian Reproduction at Bear River Migratory Bird Refuge and Great Salt Lake
  • Mercury Cycling and Bioaccumulation across the Aleutian Archipelago: Landscape Patterns of Wildlife Risk within the North Pacific Ocean
  • Mercury Cycling and Ecological Risk across Habitats in Mount Rainier National Park
  • Mercury Effects on Avian Reproduction in San Francisco Bay
  • Mercury Exposure and Risk to Purple Martins Breeding in the Willamette Valley, Oregon
  • Off-channel Habitats in the Willamette River: Implications for Methylmercury Cycling, Bioaccumulation, and Risk
  • The Effects of Wetland Restoration on Mercury Bioaccumulation in the South Bay Salt Pond Restoration Project: Using the Biosentinel Toolbox to Monitor Changes across Multiple Habitats and Spatial Scales