David Krabbenhoft is a Scientist Emeritus with the Upper Midwest Water Science Center.
David Krabbenhoft received his Ph.D. from the University of Wisconsin-Madison in 1988 and has been a research scientist with the U.S. Geological Survey since. He has general research interests are in biogeochemistry and hydrogeology of aquatic ecosystems. Dave began working on environmental mercury cycling, transformations, and fluxes in aquatic ecosystems with the Mercury in Temperate Lakes project in 1988; since then, the topic has consumed his professional life. In 1994, Dave established the USGS’s Mercury Research Laboratory, which includes a team of multi-disciplinary mercury investigators and a state-of-the-art analytical facility strictly dedicated to low-level speciation analysis of mercury. In 1995 he initiated the multi-agency Aquatic Cycling of Mercury in the Everglades (ACME) project, which is still ongoing. More recently, Dave has been a Primary Investigator on the internationally conducted Mercury Experiment To Assess Atmospheric Loadings in Canada and the US (METAALICUS) project, which is a novel effort to examine the ecosystem-level response to loading an entire watershed with mercury. Currently, Dave’s research team is active on projects that span environments as far ranging as the Pacific Ocean to freshwater systems in Alaska to Florida, and from California to New England. In recent years, the Mercury Research Team entered into the realm of atmospheric research by constructing and deployed the USGS Mobile Atmospheric Mercury Lab, which has the capability for rapid deployment and advanced study of mercury in the atmosphere. Since 1990, he has authored or coauthored over 100 papers on mercury in the environment. In August 2006, Dave served as the Co-Chair for the 8th International Conference on Mercury as a Global Pollutant.
Professional Experience
Research Hydrologist/Geochemist, U.S. Geological Survey, Wisconsin Water Science Center, 8505 Research Way, Middleton, Wisconsin, July 1988 to present.
Adjunct, University of Wisconsin-Madison, 2001 to present.
USGS Mercury Research Lab, Team Leader, 1994 to present.
Education and Certifications
Ph.D. 1988, University of Wisconsin-Madsion, Department of Geology and Geophysics; research emphasis isotope geochemistry, limnology, and hydrogeology
M.S. 1984, University of Wisconsin-Madsion, Department of Geology and Geophysics; research emphasis geochemistry and hydrogeology
B.S. 1982, North Dakota St. University, Major: Geology, Minor: Chemistry
Honors and Awards
Shoemaker Lifetime Achievement Award for Excellence in Science Communications (October 2013)
USGS performance awards (received on 24 occasions from 1988-2013)
Department of the Interior, U.S. Geological Survey, In Recognition for Meritorious Service (2003)
Department of the Interior, U.S. Geological Survey, In Recognition for Superior Service (1997)
Exxon Research Scholarship, University of Wisconsin-Madison (1982)
Summa Cum Laude, North Dakota State University (19
Science and Products
Long-Term Monitoring Reveals How Water and Biota in Remote Lakes Respond Differently to Changes in Atmospheric Deposition of Mercury
Areas of Concern: Development of St. Louis River AOC Remedial Targets for Mercury
How are Mercury Sources Determined?
Food Web Changes Dampen Expected Reductions in Lake Trout Mercury Levels in Lake Michigan—Invasive Species Play Major Role
Mercury Isotope Ratios used to Determine Sources of Mercury to Fish in Northeast U.S. Streams
Mercury studies
Mercury studies
North American and European Atmospheric Mercury Declines Explained by Local and Regional Emission Reductions
New Tool to Track Sources and Exposure Pathways of Mercury in the Environment — Application for Predatory Fish in the Great Lakes
Complex Response to Decline in Atmospheric Deposition of Mercury
Mercury cycling, bioaccumulation, and risk across western North America: a landscape scale synthesis linking long-term datasets
Environmental Mercury Cycling and Global Change
Chemical characterization of water, sediments, and fish from Water Conservation Areas and Canals of the Florida Everglades (USA), 2012 to 2019
Total mercury, bulk density, percent organic matter, and percent organic carbon measured in permafrost cores from the interior and northern slope of Alaska and previously published studies
Mercury and biogeochemical parameters in surface water and sediment from U.S. National Parks, 2014-2015
Total and Methyl Mercury Water and Fish Concentrations within Everglades National Park
Isotopic Examination of Mercury Methylation and Demethylation Rates in Yellowstone National Park Thermal Features
Yellowstone Thermal Feature Mercury and Methylmercury Characterization
Mercury source identification in the Mobile and Tombigbee Rivers
Mercury and selenium chemical characteristics and speciation data of bird, fish, and earthworm tissues
Chemical characterization of water and suspended sediment of the Snake River and Hells Canyon Complex (Idaho, Oregon) (ver. 2.0, November 2022)
Sediment biogeochemistry and subsequent mercury biomagnification in wetland food webs of the San Francisco Bay, CA
Mercury Concentrations and Mercury Isotopes in Salmonid fishes from the Snake River and tributaries in Idaho and Oregon, 2015 and 2019 (ver. 2.0, February 2021)
Mercury Bioaccumulation in US National Parks Using Dragonfly Larvae as Biosentinels, 2009-2018
Biogeochemical and hydrologic synergy control mercury fate in an arid land river-reservoir system
National-scale assessment of total gaseous mercury isotopes across the United States
The influence of short-term temporal variability on the efficacy of dragonfly larvae as mercury biosentinels
In-reservoir physical processes modulate aqueous and biological methylmercury export from a seasonally anoxic reservoir
Assessment of mercury in sediments and waters of Grubers Grove Bay, Wisconsin
Decadal trends of mercury cycling and bioaccumulation within Everglades National Park
Methylmercury stable isotopes: New insights on assessing aquatic food web bioaccumulation in legacy impacted regions
Using carbon, nitrogen, and mercury isotope values to distinguish mercury sources to Alaskan lake trout
Mercury isotope fractionation by internal demethylation and biomineralization reactions in seabirds: Implications for environmental mercury science
Demethylation of methylmercury in bird, fish, and earthworm
Isotope fractionation from In Vivo methylmercury detoxification in waterbirds
Examining historical mercury sources in the Saint Louis River estuary: How legacy contamination influences biological mercury levels in Great Lakes coastal regions
Great Lakes Mercury Sources Revealed
A new "fingerprinting" tool, developed by USGS and collaborators at University of Wisconsin-Madison, can now indicate sources of mercury in the environment.
Science and Products
- Science
Long-Term Monitoring Reveals How Water and Biota in Remote Lakes Respond Differently to Changes in Atmospheric Deposition of Mercury
A comparison of regional mercury atmospheric deposition data with water, yellow perch, and dragonfly larvae samples from lakes in Voyageurs National Park indicates that decreases in mercury emissions resulted in mercury reduction in water from these remote lakes, but mercury declines in biota were significant in only one of three lakes, likely because resident biota integrate exposure over much...Areas of Concern: Development of St. Louis River AOC Remedial Targets for Mercury
The St. Louis River Area of Concern (SLRAOC) was designated in 1987 owing to the presence of a variety of legacy pollutants, including mercury. Elevated fish-mercury levels lead fish consumption advisories by both Minnesota and Wisconsin, which resulted in Beneficial Use Impairments (BUIs).How are Mercury Sources Determined?
USGS scientists use innovative isotopic identification methods to determine mercury sources in air, water, sediments, and wildlife.Food Web Changes Dampen Expected Reductions in Lake Trout Mercury Levels in Lake Michigan—Invasive Species Play Major Role
Combined analyses of mercury, nitrogen, and carbon isotopes in archived lake trout (Salvelinus namaycush) tissues and sediment cores in Lake Michigan from 1978 to 2012 indicated that lake trout mercury concentrations mirrored declines in mercury sources prior to the arrival of invasive species that changed mercury transfer through the food and dampened the expected decreases in mercury...Mercury Isotope Ratios used to Determine Sources of Mercury to Fish in Northeast U.S. Streams
Mercury isotope analyses were used to distinguish different sources of mercury to fish in 23 streams along a forested-rural to urban-industrial land-use gradient in the Northeastern United States. The use of mercury isotope measurements in fish tissue allow for distinguishing different sources of mercury that are bioaccumulating into the food web. Mercury isotope signatures in fish in forested...Mercury studies
The USGS Mercury Research Lab is a national leader in advancing mercury research and science, specializing in low-level mercury speciation and isotope analysis and mercury-source fingerprinting. The MRL leads national cutting-edge collaborative studies, including state-of-the-art sample analysis, methods development for field and lab procedures, and data interpretation and dissemination.Mercury studies
The USGS Mercury Research Lab is a national leader in advancing mercury research and science, specializing in low-level mercury speciation and isotope analysis and mercury-source fingerprinting. The MRL leads national cutting-edge collaborative studies, including state-of-the-art sample analysis, methods development for field and lab procedures, and data interpretation and dissemination.North American and European Atmospheric Mercury Declines Explained by Local and Regional Emission Reductions
Recent findings from a consortium of university, State, and U.S. Geological Survey (USGS) scientists indicate that declining atmospheric concentrations of mercury (Hg) can be explained by the phaseout of mercury in many commercial products and by reduced emissions from utilities over the past two decades.New Tool to Track Sources and Exposure Pathways of Mercury in the Environment — Application for Predatory Fish in the Great Lakes
The US Geological Survey (USGS) and collaborators at the University of Wisconsin-Madison have developed a new tool for attributing (fingerprinting) mercury sources to the Great Lakes. This new fingerprinting tool helps resource managers understand which mitigation strategies will be most effective for reducing mercury loading and exposure to fish and wildlife.Complex Response to Decline in Atmospheric Deposition of Mercury
U.S. Geological Survey (USGS) scientists found that mercury concentrations in shallow waters and methylmercury (MeHg) concentrations in fish in four lakes in Voyageurs National Park, Minnesota, were not consistent with decreases in the wet atmospheric deposition of mercury recorded at nearby monitoring stations for over a decade. Methylmercury is a toxic form of mercury (Hg) that accumulates and...Mercury cycling, bioaccumulation, and risk across western North America: a landscape scale synthesis linking long-term datasets
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 impact tEnvironmental Mercury Cycling and Global Change
Rising global temperatures and changing human actions will significantly affect the environmental distribution of mercury worldwide, according to a recent article in Science by U.S. Geological Survey (USGS) and Harvard University scientists. Higher temperatures and weaker air circulation patterns from climate change will likely have significant impacts on the atmospheric lifetime and patterns of... - Data
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Chemical characterization of water, sediments, and fish from Water Conservation Areas and Canals of the Florida Everglades (USA), 2012 to 2019
This dataset includes field and laboratory measurements of surface waters, pore waters, sediment, and fish from Water Conservation Areas and adjacent canals of the Florida Everglades (USA). Water, sediment, and fish samples were collected from Water Conservation Areas 1 (Arthur R. Marshall Loxahatchee National Wildlife Refuge), 2, and 3 and neighboring canals between 2012 and 2019. The sites samplTotal mercury, bulk density, percent organic matter, and percent organic carbon measured in permafrost cores from the interior and northern slope of Alaska and previously published studies
This data release contains two datasets (see child items below). The first dataset, "MasterDB-csv-published-final.csv", includes 11,000 published measurements of sediment total mercury (STHg, nanograms per gram of soil, dry), bulk density (BD, grams per cm3 of soil, dry), percent of soil organic matter (%OM, loss on ignition, LOI), percent of soil organic carbon (%SOC, calculated using the RedfiMercury and biogeochemical parameters in surface water and sediment from U.S. National Parks, 2014-2015
Comma-separated values (.csv) file containing data related to mercury and biogeochemical parameters in surface water and aquatic sediment collected from U.S. National Parks in 2014-2015.Total and Methyl Mercury Water and Fish Concentrations within Everglades National Park
The data in this data release includes results from the analysis of water and fish from 76 sites in the Everglades National Park (ENP). Water and particulate matter samples were collected from 2008 to 2018 and analyzed for total mercury (THg) and methylmercury (MeHg). Filtered water samples were also analyzed for dissolved organic carbon (DOC), specific ultraviolet absorbance (SUVA), and major aniIsotopic Examination of Mercury Methylation and Demethylation Rates in Yellowstone National Park Thermal Features
Data in this data release were obtained for water samples collected under Yellowstone National Park Research Permit YELL-05194 in 2017 through the Integrated Yellowstone Studies Project funded by the Mineral Resources Program. Isotope-spiked incubations were carried out to determine methylation and demethylation potential for Frying Pan spring, Crystal Sister East, Crystal Sister West, and TurbuleYellowstone Thermal Feature Mercury and Methylmercury Characterization
Data in this data release were obtained from water samples collected under Yellowstone National Park (YNP) Research Permit YELL-05194 in 2017, 2019, and 2020 through the Integrated Yellowstone Studies Project funded by the Mineral Resources Program. These samples were used to assess mercury cycling within YNP. Water samples were analyzed for total mercury and methylmercury, the bioaccumulated formMercury source identification in the Mobile and Tombigbee Rivers
This dataset details mercury concentrations and mercury stable isotope values collected as part of an environmental mercury assessment encompassing the Mobile and Tombigbee Rivers as well as two U.S. Environmental Protection Agency Superfund sites. The Tensaw River was also sampled as part of this study as a reference site, absent of mercury contamination. As a part of this survey, sediments, wateMercury and selenium chemical characteristics and speciation data of bird, fish, and earthworm tissues
Birds (Clark's grebe, Aechmophorus clarkii; Forster's Tern, Sterna forsteri), fish (Peacock bass, Cichla temensis, Cichla monoculus; Pescada, Plagioscion squamosissimus) and earthworms were analyzed for selenium, total mercury, and methyl mercury concentration and mercury speciation. A Clark's grebe was collected from Lake Berryessa (California, United States) in September 2012. A Forster's Tern wChemical characterization of water and suspended sediment of the Snake River and Hells Canyon Complex (Idaho, Oregon) (ver. 2.0, November 2022)
This dataset includes laboratory analyses of surface water samples and sediment trap material collected from (1) locations upstream, downstream, and within the Hells Canyon Complex (Idaho, Oregon) of the Snake River, (2) tributaries of the Snake River, and (3) two reservoirs near Boise, Idaho, from 2014 to 2021. The study area spans approximately 232 river miles of the Snake River and includes: twSediment biogeochemistry and subsequent mercury biomagnification in wetland food webs of the San Francisco Bay, CA
Methylmercury (MeHg) is a globally pervasive contaminant that biomagnifies in food webs and can reach toxic concentrations in consumers at higher trophic levels, including wildlife and humans. The production of MeHg, and its subsequent entry and biomagnification in food webs, is governed by a complex suite of biogeochemical, physical, and ecological processes, resulting in variation in the distribMercury Concentrations and Mercury Isotopes in Salmonid fishes from the Snake River and tributaries in Idaho and Oregon, 2015 and 2019 (ver. 2.0, February 2021)
Comma-separated values (.csv) file containing data related to mercury in Salmonid fishes collected from the Snake River and tributaries, Idaho and Oregon.Mercury Bioaccumulation in US National Parks Using Dragonfly Larvae as Biosentinels, 2009-2018
Comma-separated values (.csv) files containing data related to a National-scale assessment of mercury bioaccumulation in the US National Parks using dragonfly larvae as biosentinels through a citizen science framework. - Multimedia
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Filter Total Items: 188
Biogeochemical and hydrologic synergy control mercury fate in an arid land river-reservoir system
Reservoirs in arid landscapes provide critical water storage and hydroelectric power but influence the transport and biogeochemical cycling of mercury (Hg). Improved management of reservoirs to mitigate the supply and uptake of bioavailable methylmercury (MeHg) in aquatic food webs will benefit from a mechanistic understanding of inorganic divalent Hg (Hg(II)) and MeHg fate within and downstream oAuthorsBrett Poulin, Michael T. Tate, Jacob M. Ogorek, Sara Breitmeyer, Austin K. Baldwin, Alysa Muir Yoder, Reed C. Harris, Jesse Naymik, Nick Gastelecutto, Charles Hoovestol, Christopher F. Larsen, Ralph Myers, George R. Aiken, David P. KrabbenhoftNational-scale assessment of total gaseous mercury isotopes across the United States
With the 2011 promulgation of the Mercury and Air Toxics Standards by the U.S. Environmental Protection Agency, and the successful negotiation by the United Nations Environment Program of the Minamata Convention, emissions of mercury (Hg) have declined in the United States. While the declines in atmospheric Hg concentrations in North America are encouraging, linking the declines to changing domestAuthorsMichael T. Tate, Sarah E. Janssen, Ryan F. Lepak, Laura Elizabeth Flucke, David P. KrabbenhoftThe influence of short-term temporal variability on the efficacy of dragonfly larvae as mercury biosentinels
Mercury (Hg) exposure to fish, wildlife, and humans is widespread and of global concern, thus stimulating efforts to reduce emissions. Because the relationships between rates of inorganic Hg loading, methylmercury (MeHg) production, and bioaccumulation are extremely complex and challenging to predict, there is a need for reliable biosentinels to understand the distribution of Hg in the environmentAuthorsJames Willacker, Collin Eagles-Smith, Sarah J. Nelson, Colleen M. Flanagan-Pritz, David P. KrabbenhoftIn-reservoir physical processes modulate aqueous and biological methylmercury export from a seasonally anoxic reservoir
Anoxic conditions within reservoirs related to thermal stratification and oxygen depletion lead to methylmercury (MeHg) production, a key process governing the uptake of mercury in aquatic food webs. Once formed within a reservoir, the timing and magnitude of the biological uptake of MeHg and the relative importance of MeHg export in water versus biological compartments remain poorly understood. WAuthorsAustin K. Baldwin, Collin Eagles-Smith, James Willacker, Brett Poulin, David P. Krabbenhoft, Jesse Naymik, Michael T. Tate, Dain Bates, Nick Gastelecutto, Charles Hoovestol, Christopher F. Larsen, Alysa Muir Yoder, James A. Chandler, Ralph MyersAssessment of mercury in sediments and waters of Grubers Grove Bay, Wisconsin
Mercury is a global contaminant that can be detrimental to wildlife and human health. Anthropogenic emissions and point sources are primarily responsible for elevated mercury concentrations in sediments and waters. Mercury can physically move and chemically transform in the environment, resulting in biomagnification of mercury, in the form of methylmercury, in the food web and causing elevated merAuthorsEvan J. Routhier, Sarah E. Janssen, Michael T. Tate, Jacob M. Ogorek, John F. DeWild, David P. KrabbenhoftDecadal trends of mercury cycling and bioaccumulation within Everglades National Park
Mercury (Hg) contamination has been a persistent concern in the Florida Everglades for over three decades due to elevated atmospheric deposition and the system's propensity for methylation and rapid bioaccumulation. Given declines in atmospheric Hg concentrations in the conterminous United States and efforts to mitigate nutrient release to the greater Everglades ecosystem, it was vital to assess hAuthorsSarah E. Janssen, Michael T. Tate, Brett Poulin, David P. Krabbenhoft, John F DeWild, Jacob M. Ogorek, Matthew S. Varonka, William H. Orem, Jeffrey D KlineMethylmercury stable isotopes: New insights on assessing aquatic food web bioaccumulation in legacy impacted regions
Through stable isotope measurements of total mercury (HgT), identification of crucial processes and transformations affecting different sources of mercury (Hg) has become possible. However, attempting to use HgT stable isotopes to track bioaccumulation of Hg sources among different food web compartments can be challenging, if not impossible, when tissues have varying methylmercury (MeHg) contents.AuthorsTylor Rosera, Sarah E. Janssen, Michael T. Tate, Ryan F. Lepak, Jacob M. Ogorek, John F. DeWild, David P. Krabbenhoft, James P. HurleyUsing carbon, nitrogen, and mercury isotope values to distinguish mercury sources to Alaskan lake trout
Lake trout (Salvelinus namaycush), collected from 13 remote lakes located in southwestern Alaska, were analyzed for carbon, nitrogen, and mercury (Hg) stable isotope values to assess the importance of migrating oceanic salmon, volcanic activity, and atmospheric deposition to fish Hg burden. Methylmercury (MeHg) bioaccumulation in phytoplankton (5.0–6.9 kg L–1) was also measured to quantify the basAuthorsRyan F. Lepak, Jacob M. Ogorek, Krista K. Bartz, Sarah E. Janssen, Michael T. Tate, Yin Runsheng, James P. Hurley, Daniel B. Young, Collin Eagles-Smith, David P. KrabbenhoftMercury isotope fractionation by internal demethylation and biomineralization reactions in seabirds: Implications for environmental mercury science
A prerequisite for environmental and toxicological applications of mercury (Hg) stable isotopes in wildlife and humans is quantifying the isotopic fractionation of biological reactions. Here, we measured stable Hg isotope values of relevant tissues of giant petrels (Macronectes spp.). Isotopic data were interpreted with published HR-XANES spectroscopic data that document a stepwise transformationAuthorsAlain Manceau, Romain Brossier, Sarah E. Janssen, Tylor Rosera, David P. Krabbenhoft, Yves Cherel, Paco Bustamante, Brett PoulinDemethylation of methylmercury in bird, fish, and earthworm
Toxicity of methylmercury (MeHg) to wildlife and humans results from its binding to cysteine residues of proteins, forming MeHg-cysteinate (MeHgCys) complexes that hinder biological functions. MeHgCys complexes can be detoxified in vivo, yet how this occurs is unknown. We report that MeHgCys complexes are transformed into selenocysteinate (Hg(Sec)4) complexes in multiple animals from two phyla (aAuthorsAlain Manceau, Jean-Paul Bourdineaud, Ricardo B. Oliveira, Sandra LF Sarrazin, David P. Krabbenhoft, Collin Eagles-Smith, Josh T. Ackerman, Robin Stewart, Christian Ward-Deitrich, M Estela del Castillo Busto, Heidi Goenaga-Infante, Aude Wack, Marius Retegan, Blanka Detlefs, Pieter Glatzel, Paco Bustamante, Kathryn L. Nagy, Brett PoulinIsotope fractionation from In Vivo methylmercury detoxification in waterbirds
The robust application of stable mercury (Hg) isotopes for mercury source apportionment and risk assessment necessitates the understanding of mass-dependent fractionation (MDF) due to internal transformations within organisms. Here, we used high energy-resolution XANES spectroscopy and isotope ratios of total mercury (δ202THg) and methylmercury (δ202MeHg) to elucidate the chemical speciation of HgAuthorsBrett Poulin, Sarah Elizabeth Janssen, Tylor Rosera, David P. Krabbenhoft, Collin Eagles-Smith, Josh T. Ackerman, Robin Stewart, Eunhee Kim, Zofia Baumann, Jeong-Hoon Kim, Alain ManceauExamining historical mercury sources in the Saint Louis River estuary: How legacy contamination influences biological mercury levels in Great Lakes coastal regions
Industrial chemical contamination within coastal regions of the Great Lakes can pose serious risks to wetland habitat and offshore fisheries, often resulting in fish consumption advisories that directly affect human and wildlife health. Mercury (Hg) is a contaminant of concern in many of these highly urbanized and industrialized coastal regions, one of which is the Saint Louis River estuary (SLRE)AuthorsSarah E. Janssen, Joel C. Hoffman, Ryan F. Lepak, David P. Krabbenhoft, David Walters, Collin Eagles-Smith, Greg Peterson, Jacob M. Ogorek, John F. DeWild, Anne M Cotter, Mark Pearson, Michael T. Tate, Roger B. Yeardley, Marc A. Mills - News
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Great Lakes Mercury Sources Revealed
A new "fingerprinting" tool, developed by USGS and collaborators at University of Wisconsin-Madison, can now indicate sources of mercury in the environment.