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Person

James J Willacker

Ecologist

Email: jwillacker@usgs.gov
Office Phone: 541-750-0957
ORCID: 0000-0002-6286-5224

Location
3200 S.W. Jefferson Way
Corvallis , OR 97331
US
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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 unique and complex mosaic of ecological risk from Hg impairment associated with differential methylmercury (MeHg) production and bioaccumulation. Understanding the landscape-scale variation in the magnitude and relative importance of processes associated with Hg transport, methylation, and MeHg bioaccumulation requires a multidisciplinary synthesis that transcends small-scale...
Categories: Publication; Types: Citation
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These data were compiled to study mercury and selenium concentrations in fish species and assemblages in lotic waterbodies across the Upper Colorado River Basin. Data were compiled from State and Federal agencies. This data table contains raw concentration data, as well as standardized concentrations corrected for differences based on sample type (i.e., tissue type), species-specific bioaccumulation rates (Table S1), and fish size (Table S2). The data were used in linear mixed effects models to estimate average mercury and selenium concentration in fish species and in fish assemblages, including fish total length (cm), sampling location (Sub basin name and GPS coordinates), and sampling year (Figures 2,3, and 4...
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Comma-separated values (.csv) file containing data related to mercury concentrations in dragonfly samples from U.S. National Parks collected as part of the Dragonfly Mercury Project (DMP). This data release supersedes Eagles-Smith, C.A., Nelson, S.J., Flanagan-Pritz, C.M., Willacker Jr., J.J., and Klemmer, A.J., 2018, Total mercury concentrations in dragonfly larvae from U.S. national parks (ver. 8.0, December 2022): U.S. Geological Survey data release, https://doi.org/10.5066/P9TK6NPT. Please contact fresc_outreach@usgs.gov for access.
Categories: Data, Data Release - Revised; Tags: Acadia National Park, Allegheny Portage Railroad National Historic Site, Amistad National Recreation Area, Apostle Islands National Lakeshore, Appomattox Court House National Historical Park, All tags...
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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 in the west limits the distribution of avian piscivore species, complicating broad comparisons across the region. Mercury risk to avian piscivores was evaluated across the western United States and Canada using a suite of avian piscivore species representing a variety of foraging strategies that together occur broadly across the region. Prey fish Hg concentrations were...
Categories: Publication; Types: Citation
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This dataset includes field hydrologic measurements and laboratory analyses of surface and pore waters, sediments, benthic plants/biofilms, and biota along the Middle Snake River upgradient of the Hells Canyon Complex. The study region for this work focuses on a section of the Snake River heavily utilized for agriculture, with complex systems of irrigation diversion and return drainage, spanning 164 km above the Hells Canyon Complex (Idaho, Oregon). The goal of this study was to identify potential loading sources of methylmercury from the upgradient Snake River into the reservoir complex, with a focus on the tributaries, irrigation return drains, and riparian zones adjacent to agricultural lands along the river....
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