Fish mercury data from State monitoring programs and research studies within the Chesapeake Bay were compiled and summarized to provide a comprehensive overview of the variation in fish mercury concentrations among species and habitats within the watershed. These data are put into context with existing health benchmarks for humans, birds, and fish. Scientists also provide a roadmap for an...
In a study designed to help resource managers when considering mercury exposure risk, scientists determined that sulfur cycling—a process closely related to mercury methylation rates—and ecological conditions that influence exposure are important factors affecting fish mercury concentrations in estuarine wetlands.
The FRESC Contaminant Ecology research program evaluates the distribution, movement, and ecological effects of environmental contaminants across the landscape and strives to provide relevant science in support of natural resource conservation, management, and decision making.
Mercury (Hg) is a serious environmental problem that is impacting ecological and human health on a global scale. However, local and regional processes are largely responsible for producing methylmercury, which drives ecological risk. This is particularly true in western North America where the combination of diverse landscapes, habitat types, climates, and Hg sources may disproportionally...
Montane meadows are areas of high biodiversity and provide many important ecosystem services; however, degradation of 40–60% of these habitats in the Sierra Nevada region of California has left many of these areas impaired. The “pond-and-plug” meadow-restoration technique is 1 type of treatment implemented to restore montane meadows. The...
Tennant, Lora; Eagles-Smith, Collin; Willacker, James; Johnson, Matthew We conducted a national-scale assessment of mercury (Hg) bioaccumulation in aquatic ecosystems using dragonfly larvae as biosentinels, by developing a citizen science network to facilitate biological sampling. Implementing a carefully designed sampling methodology for citizen scientists, we developed an effective framework for landscape-level...
Eagles-Smith, Collin; Willacker, James; Nelson, Sarah J.; Flanagan Pritz, Collen M; Krabbenhoft, David P.; Chen, Celia Y.; Ackerman, Joshua T.; Campbell Grant, Evan H.; Pilliod, David Chemical contaminants are a threat to the Chesapeake Bay watershed, with mercury (Hg) among the most prevalent causes of impairment. Despite this, large-scale patterns of Hg concentrations, and the potential risks to fish, wildlife, and humans across the watershed, are poorly understood. We compiled fish Hg data from state monitoring programs and...
Willacker, James; Eagles-Smith, Collin; Blazer, Vicki S. Mercury (Hg) and selenium (Se) are contaminants of concern for fish in the Upper Colorado River Basin (UCRB). We explored Hg and Se in fish tissues (2,324 individuals) collected over 50 years (1962–2011) from the UCRB. Samples include native and non-native fish collected from lotic waterbodies spanning 7 major tributaries to the Colorado River....
Day, Natalie K.; Schmidt, Travis; Roberts, James J.; Osmundson, Barbara C.; Willacker, James; Eagles-Smith, Collin Timber harvest has many effects on aquatic ecosystems, including changes in hydrological, biogeochemical, and ecological processes that can influence mercury (Hg) cycling. Although timber harvest’s influence on aqueous Hg transformation and transport are well studied, the effects on Hg bioaccumulation are not. We evaluated Hg bioaccumulation,...
Willacker, James; Eagles-Smith, Collin A.; Kowalski, Brandon M; Danehy, Robert J; Jackson, Allyson K.; Adams, Evan M.; Evers, David C.; Eckley, Chris S.; Tate, Michael T.; Krabbenhoft, David P. Estuaries are transitional habitats characterized by complex biogeochemical and ecological gradients that result in substantial variation in fish total mercury concentrations (THg). We leveraged these gradients and used carbon (δ13C), nitrogen (δ15N), and sulfur (δ34S) stable isotopes to examine the ecological and biogeochemical processes...
Willacker, James J.; Eagles-Smith, Collin A.; Ackerman, Joshua T. Anthropogenic manipulation of aquatic habitats can profoundly alter mercury (Hg) cycling and bioaccumulation. The impoundment of fluvial systems is among the most common habitat manipulations and is known to increase fish Hg concentrations immediately following impoundment. However, it is not well understood how Hg concentrations differ between...
Willacker, James J.; Eagles-Smith, Collin A.; Lutz, Michelle A.; Tate, Michael T.; Lepak, Jesse M.; Ackerman, Joshua T. Fish represent high quality protein and nutrient sources, but Hg contamination is ubiquitous in aquatic ecosystems and can pose health risks to fish and their consumers. Potential health risks posed to fish and humans by Hg contamination in fish were assessed in western Canada and the United States. A large compilation of inland fish Hg...
Lepak, Jesse M.; Hooten, Mevin; Eagles-Smith, Collin A.; Tate, Michael T.; Lutz, Michelle A.; Ackerman, Joshua T.; Willacker, James J.; Jackson, Allyson K.; Evers, David C.; Wiener, James G.; Pritz, Colleen Flanagan; Davis, Jay The widespread distribution of mercury (Hg) threatens wildlife health, particularly piscivorous birds. Western North America is a diverse region that provides critical habitat to many piscivorous bird species, and also has a well-documented history of mercury contamination from legacy mining and atmospheric deposition. The diversity of landscapes...
Jackson, Allyson K.; Evers, David C.; Eagles-Smith, Collin A.; Ackerman, Joshua T.; Willacker, James J.; Elliott, John E.; Lepak, Jesse M.; Vander Pol, Stacy S.; Bryan, Colleen E. Western North America is a region defined by extreme gradients in geomorphology and climate, which support a diverse array of ecological communities and natural resources. The region also has extreme gradients in mercury (Hg) contamination due to a broad distribution of inorganic Hg sources. These diverse Hg sources and a varied landscape create a...
Eagles-Smith, Collin A.; Wiener, James G.; Eckley, Chris S.; Willacker, James J.; Evers, David C.; Marvin-DiPasquale, Mark C.; Obrist, Daniel; Fleck, Jacob; Aiken, George R.; Lepak, Jesse M.; Jackson, Allyson K.; Webster, Jackson; Stewart, Robin; Davis, Jay; Alpers, Charles N.; Ackerman, Joshua T. Methylmercury contamination of fish is a global threat to environmental health. Mercury (Hg) monitoring programs are valuable for generating data that can be compiled for spatially broad syntheses to identify emergent ecosystem properties that influence fish Hg bioaccumulation. Fish total Hg (THg) concentrations were evaluated across the Western...
Eagles-Smith, Collin A.; Ackerman, Joshua T.; Willacker, James J.; Tate, Michael T.; Lutz, Michelle A.; Fleck, Jacob; Stewart, Robin; Wiener, James G.; Evers, David C.; Lepak, Jesse M.; Davis, Jay A.; Pritz, Colleen Flanagan
Mercury is a globally distributed pollutant that threatens human and ecosystem health. Even protected areas, such as national parks, are subjected to mercury contamination because it is delivered through atmospheric deposition, often after long-range transport. In aquatic ecosystems, certain environmental conditions can promote microbial processes...
Eagles-Smith, Collin A.; Nelson, Sarah J.; Willacker,, James J.; Flanagan Pritz, Colleen M.; Krabbenhoft, David P.
The ‘‘pond-and-plug’’ meadow-restoration technique, in which ponds are formed by excavating the floodplain and plugging incised channels with the excavated material, is commonly used in montane meadows in the Sierra Nevada.
Despite the prevalence of mercury contamination in the Chesapeake Bay, large-scale patterns of mercury concentrations, and potential risks to fish, wildlife, and humans across the watershed, are poorly understood.
Land use change is an important driver of global mercury cycling. Timber harvest is a common land use that can alter associated aquatic ecosystems, yet little is known about how it affects mercury concentrations and associated food web changes.