Christopher Conaway
Christopher Conaway is a Research Chemist in the USGS Water Mission Area Earth System Processes Division, where he conducts research to improve the understanding of environmental aspects of energy resources, climate change, carbon cycling and sequestration, water quality, and subsurface hydrology using geochemical approaches such as the use of isotopic tracers, trace elements, and radioisotopes.
Christopher (Kit) Conaway is a geochemist with the USGS Water Mission Area Earth System Processes Division. His research has focused on the sampling and analysis of produced waters from geologic carbon sequestration studies, geochemical characterization of sediment transport in the coastal zone, the environmental chemistry of mercury in coastal regions, and water quality analysis for samples from areas of mineralized rock, mining activity, and wetlands. His current work focuses principally isotope geochemistry in hydrological and biogeochemical applications.
Christopher completed a B.A. degree in English literature at the Ohio State University in 1993, an M.S. in geology at the Ohio State University in 1999, and a Ph.D. in environmental toxicology and chemistry at the University of California Santa Cruz in 2003. Prior to his current position at USGS, he was a USGS Mendenhall Scholar at the Pacific Coastal and Marine Science Center, and then worked in the USGS National Research Program.
Science and Products
Energy Integrated Science Team
The Energy Lifecycle Integrated Science Team focuses on the potential for contaminant exposures in the environment that might originate from energy resource activities including, extraction, production, transportation, storage, extraction, waste management and restoration. Perceived health risks to humans and other organisms will be distinguished from actual risks, if any. If actual risks are...
Amargosa Desert Research Site
In 1976, the U.S. Geological Survey (USGS) began studies of unsaturated zone hydrology at a site in the Amargosa Desert near Beatty, Nevada, as part of the USGS Low-Level Radioactive Waste Program. The site is near disposal trenches for civilian waste. Over the years, USGS investigations at the Amargosa Desert Research Site (ADRS) have provided long-term "benchmark" information about the hydraulic...
Elemental partitioning between aqueous and solid phases of mercury and other constituents associated with Marcellus Shale Energy and Environment Laboratory (MSEEL) gas well production waste water, Morgantown, WV, 2015 - 2018.
The Marcellus Shale Energy and Environment Laboratory (MSEEL) site is a long-term field site and laboratory at the Northeast Natural Energy LLC (NNE) production facility, adjacent to the Monongahela River, located in western Monongalia County, West Virginia, USA. NNE began drilling two horizontal production wells, MIP (Morgantown Industrial Park) -5H and MIP-3H, in the Marcellus Shale in 2014. The
Geochemistry and microbiology data collected to study the effects of oil and gas wastewater dumping on arid lands in New Mexico
The Permian Basin, straddling New Mexico and Texas, is one of the most productive oil and gas (OG) provinces in the United States. OG production yields large volumes of wastewater that contain elevated concentrations of major ions including salts (also referred to as brines), and trace organic and inorganic constituents. These OG wastewaters pose unknown environmental health risks, particularly in
By
Water Resources Mission Area, Energy Resources Program, Environmental Health Program, Columbia Environmental Research Center, Geology, Energy & Minerals Science Center, Eastern Energy and Environmental Laboratory (EEEL), Reston Biogeochemical Processes in Groundwater Laboratory, Reston Microbiology Laboratory
Geochemistry of surface sediment and sediment cores in Bellingham Bay, Whatcom County, Washington, in February 2020
Geochemical data are reported for surface sediments and long sediment cores from Bellingham Bay, Whatcom County, Washington, collected in early February 2020 after flood conditions on the Nooksack River. Data include total organic carbon content (TOC), carbonate content (CaCO3), ratios of stable carbon 13/12 isotopes (d13C), ratios of total carbon to total nitrogen (C:N), short-lived cosmogenic ra
Polycyclic aromatic hydrocarbons (PAHs) and suspended sediment concentrations in the San Lorenzo River, Santa Cruz, California, USA
Water from the San Lorenzo River in Santa Cruz, California, was sampled to analyze for polycyclic aromatic hydrocarbons (PAHs) and suspended sediment concentrations (SSC) during the rainy seasons from 2008 to 2019 following drought conditions. The samples were collected using a US D-95 depth-integrated water sampler deployed from a bridge-box platform beneath a pedestrian bridge For each suspende
Parent and alkylated polycyclic aromatic hydrocarbons (PAHs) and per- and polyfluoroalkyl substances (PFAS) in north San Francisco Bay, Napa River, and Sonoma Creek in 2018 and 2019
Sediment grain-size distributions, stable carbon isotope ratios (d13C), total carbon to total nitrogen ratios (C:N), short-lived radionuclides (Beryllium-7, Cesium-137, and Lead-210), concentrations of 76 parent and alkylated polycyclic aromatic hydrocarbons (PAHs) and concentrations of 33 per- and polyfluoroalkyl substances (PFAS) were measured in the northern reach of San Francisco Bay (San Pabl
Chemical characterization of water and suspended sediment of the Snake River and Hells Canyon Complex (Idaho, Oregon) (ver. 3.0, November 2023)
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: tw
Microbial Carbon and Nitrogen Metabolism Across a Late Pleistocene Permafrost Chronosequence
This data release includes all of the data presented in the peer-reviewed publication "Life at the frozen limit: Microbial Carbon Metabolism Across a Late Pleistocene Permafrost Chronosequence". We collected permafrost from a Pleistocene chronosequence (19 ka to 33 ka) to examine (1) changes in the functional genetic potential of extant microbial communities to metabolize polysaccharides, (2) shif
Sediment Mercury Profile, Laguna de Pozuelos, Argentine Northwest
The data represent a shallow mercury chronology using sediment core from a playa lake system situated in a high-altitude setting in northwest Argentina. Archive samples were used from sediment core (LP07-1A) that was collected from a location (lat -22.362100, lon -66.003600) in the center of the playa-lake Laguna de Pozuelos in the dry season of 2007, when the water level was 2 to 3 cm. The sample
Permafrost Mapping in Two Wetland Systems North of the Tanana River in Interior Alaska 2014
Surface-based 2D electrical resistivity tomography (ERT) surveys were used to investigate the distribution of permafrost at wetland sites on the alluvial plain north of the Tanana River, 20 km southwest of Fairbanks, Alaska, in June and September 2014. The sites contained habitat types characteristic of interior Alaska, including thermokarst bog, forested permafrost plateau, and a rich fen. These
Data for Biogeochemical and Physical Processes Controlling Mercury Methylation and Bioaccumulation in Lake Powell, Glen Canyon National Recreation Area, Utah and Arizona
This dataset includes the field measurements and laboratory analyses of surface water, seston, and sediment collected from Lake Powell, within Glen Canyon National Recreation area (GLCA), during high flow (May-June 2014) and low flow (August 2015) conditions. The study area includes 12-13 sampling sites that follow a transect spanning the entire length of the reservoir from the Colorado River infl
Filter Total Items: 23
Knowledge gaps and opportunities in water-quality drivers of aquatic ecosystem health
This report identifies key scientific gaps that limit our ability to predict water quality effects on health of aquatic ecosystems and proposes approaches to address those gaps. Topics considered include (1) coupled nutrient-carbon cycle processes and related ecological-flow-regime drivers of ecosystem health, (2) anthropogenic and geogenic toxin bioexposure, (3) fine sediment drivers of aquatic e
Knowledge gaps and opportunities for understanding water-quality processes affecting water availability for beneficial uses
This report describes scientific gaps that limit our ability to predict water-quality effects on water availability for beneficial uses across the United States. Water-quality constituents considered in the report include salinity, geogenic constituents, contaminants of emerging concern, and nitrogen. For each constituent, there is a selection of scientific gaps, approaches, and outcomes to help g
Examining terrestrial and subterranean sediment sources and transport processes in an urban sewershed with an entirely buried stream network, Washington, D.C., United States
Excessive fine-grained sediment runoff due to anthropogenic activities is a major environmental concern for watersheds worldwide, especially so for urban areas such as Washington, D.C. Dated grey infrastructure, i.e., the network of buried pipes and reservoirs managing water resources, can amplify existing issues with sediment runoff and associated pollutants. This infrastructure, which is general
Authors
Zachary Clifton, Allen C. Gellis, Leah Ellen Staub, Matt J. Cashman, Christopher H. Conaway, Cecilia Lane, David Pilat
Mechanisms for retention of low molecular weight organic carbon varies with soil depth at a coastal prairie ecosystem
Though primary sources of carbon (C) to soil are plant inputs (e.g., rhizodeposits), the role of microorganisms as mediators of soil organic carbon (SOC) retention is increasingly recognized. Yet, insufficient knowledge of sub-soil processes complicates attempts to describe microbial-driven C cycling at depth as most studies of microbial-mineral-C interactions focus on surface horizons. We leverag
Authors
Jack McFarland, Corey Lawrence, Courtney Creamer, Marjorie S. Schulz, Christopher H. Conaway, Sara Peek, Mark Waldrop, Sabrina N. Sevilgen, Monica Haw
Permafrost mapping with electrical resistivity tomography in two wetland systems north of the Tanana River, Interior Alaska
Surface-based 2D electrical resistivity tomography (ERT) surveys were used to characterize permafrost distribution at wetland sites on the alluvial plain north of the Tanana River, 20 km southwest of Fairbanks, Alaska, in June and September 2014. The sites were part of an ecologically-sensitive research area characterizing biogeochemical response of this region to warming and permafrost thaw, and
Authors
Christopher H. Conaway, Cordell Johnson, Thomas Lorenson, Merritt R. Turetsky, Eugénie S. Euskirchen, Mark Waldrop, Peter W. Swarzenski
Life at the frozen limit: Microbial carbon metabolism across a Late Pleistocene permafrost chronosequence
Permafrost is an extreme habitat yet it hosts microbial populations that remain active over millennia. Using permafrost collected from a Pleistocene chronosequence (19 to 33 ka), we hypothesized that the functional genetic potential of microbial communities in permafrost would reflect microbial strategies to metabolize permafrost soluble organic matter (OM) in situ over geologic time. We also hypo
Authors
Mary-Cathrine Leewis, Renaud Berlemont, David C. Podgorski, Archana Srinivas, Phoebe Zito, Robert G. M. Spencer, Jack McFarland, Thomas A. Douglas, Christopher H. Conaway, Mark Waldrop, Rachel Mackelprang
Chemical composition of formation water in shale and tight reservoirs: A basin-scale perspective
No abstract available.
Authors
Yousif Kharaka, Kathleen Gans, Elisabeth Rowan, James Thordsen, Christopher H. Conaway, Madalyn S. Blondes, Mark A. Engle
Spatial fingerprinting of biogenic and anthropogenic volatile organic compounds in an arid unsaturated zone
Subsurface volatile organic compounds (VOCs) can pose risks to human and environmental health and mediate biological processes. VOCs have both anthropogenic and biogenic origins, but the relative importance of these sources has not been explored in subsurface environments. This study synthesizes 17 years of VOC data from the Amargosa Desert Research Site (ADRS) with the goal of improving understan
Authors
Christopher Green, Wentai Luo, Christopher H. Conaway, Karl B. Haase, Ronald J. Baker, Brian J. Andraski
Biogeochemical and physical processes controlling mercury methylation and bioaccumulation in Lake Powell, Glen Canyon National Recreation Area, Utah and Arizona, 2014 and 2015
Mercury monitoring results from about 300 Morone saxatilis (striped bass) muscle tissue samples collected by the State of Utah from Lake Powell resulted in a Utah/Arizona fish consumption advisory issued in 2012 for approximately the lower 100 kilometers of the reservoir. Chemical, physical, and biological data were collected during two synoptic sampling cruises on Lake Powell during May/June 2014
Authors
David L. Naftz, Mark Marvin-DiPasquale, David P. Krabbenhoft, George Aiken, Eric S. Boyd, Christopher H. Conaway, Jacob M. Ogorek, Gregory M. Anderson
Unsaturated zone CO2, CH4, and δ13C-CO2 at an arid region low-level radioactive waste disposal site
Elevated tritium, radiocarbon, Hg, and volatile organic compounds associated with low-level radioactive waste (LLRW) at the USGS Amargosa Desert Research Site (ADRS) have stimulated research on factors and processes that affect contaminant gas distribution and transport. Consequently, we examined the sources, mixing, and biogeochemistry of CO2 and CH4, two additional important species in the unsat
Authors
Christopher H. Conaway, Michelle Ann Walvoord, Randall B. Thomas, Christopher Green, R.J. Baker, James J. Thordsen, David A. Stonestrom, Brian J. Andraski
A regime shift in sediment export from a coastal watershed during a record wet winter, California: Implications for landscape response to hydroclimatic extremes
Small, steep watersheds are prolific sediment sources from which sediment flux is highly sensitive to climatic changes. Storm intensity and frequency are widely expected to increase during the 21st century, and so assessing the response of small, steep watersheds to extreme rainfall is essential to understanding landscape response to climate change. During record winter rainfall in 2016–2017, the
Authors
Amy E. East, Andrew W. Stevens, Andrew C. Ritchie, Patrick L. Barnard, Pamela L. Campbell‐Swarzenski, Brian D. Collins, Christopher H. Conaway
Microbial survival strategies in ancient permafrost: insights from metagenomics
In permafrost (perennially frozen ground) microbes survive oligotrophic conditions, sub-zero temperatures, low water availability and high salinity over millennia. Viable life exists in permafrost tens of thousands of years old but we know little about the metabolic and physiological adaptations to the challenges presented by life in frozen ground over geologic time. In this study we asked whether
Authors
Rachel Mackelprang, Alexander Burkert, Monica Haw, Tara Mahendrarajah, Christopher H. Conaway, Thomas A. Douglas, Mark P. Waldrop
Non-USGS Publications**
Flegal, A.R., Gallon, C., Ganguli, P.M., and Conaway, C.H. (2013) All the Lead in China. Critical Reviews in Environmental Science and Technology 43: 1869–1944
Gallon, C, Ranville, M.A., Conaway, C.H., Landing, W., Buck, C., Morton, P., and Flegal, A.R. (2011) Asian industrial lead inputs to the North Pacific evidenced by lead concentrations and isotopic compositions in surface waters and aerosols. Environmental Science & Technology 45(23):9874–9882
Conaway, C.H., Black, F.J., Weiss-Penzias, P., Gault-Ringold, M., and Flegal, A.R. (2010) Mercury speciation in Pacific coastal rainwater, Monterey Bay, California. Atmospheric Environment 44(14): 1788–1797
Black, F.J., Conaway, C.H., and Flegal, A.R. (2009) Stability of dimethyl mercury in seawater and its conversion to monomethyl mercury. Environmental Science & Technology 43(11): 4056–4062
Conaway, C.H., Black, F.J., Gault-Ringold, M., Pennington, J.T., Chavez, F.P., and Flegal, A.R. (2009) Dimethylmercury in coastal upwelling waters, Monterey Bay, California. Environmental Science & Technology 43(5): 1305–1309
N. David, L.J. McKee, F.J. Black, A.R. Flegal, C.H. Conaway, D.H. Schoellhamer, N.K. Ganju
2009, Environmental Toxicology and Chemistry (28) 2091–2100
2009, Environmental Toxicology and Chemistry (28) 2091–2100
Conaway, C.H., Black, F.J., Grieb, T.M, Roy, S., and Flegal, A.R. (2008) Mercury in the San Francisco Estuary. Reviews of Environmental Contamination and Toxicology 194: 29–54
Conaway, C.H., Ross, J.R.M., Looker, R., Mason, R.P., and Flegal, A.R. (2007) Decadal mercury trends in San Francisco Estuary sediments. Environmental Research 105(1): 53–66
Conaway, C.H., Pride D.E., Faure, G., and Tettenhorst, R.T. (2005) Mineralogical and geochemical investigation of sediment in the Snake River arm of the Dillon Reservoir, Summit County, Colorado. Lakes and Reservoirs: Research and Management 10: 235–242
Conaway, C.H., Mason, R.P., Steding, D.J., and Flegal, A.R. (2005) Estimate of mercury emission from gasoline and diesel fuel consumption, San Francisco Bay area, California. Atmospheric Environment 39(1): 101–105
Flegal, A.R., Conaway, C.H., Scelfo, G.M., Hibdon, S., Sañudo-Wilhelmy, S.A. (2005) Factors influencing measurements of decadal variations in metal contamination in San Francisco Bay, California. Ecotoxicolgy 14(6): 645–660
Conaway, C.H., Watson, E. Flanders, J.R., and Flegal, A.R. (2004) Mercury deposition in a tidal marsh of south San Francisco Bay downstream of the historic New Almaden mining district, California. Marine Chemistry 90(1–4): 175–184
Conaway, C.H., Squire, S., Mason, R.P., and Flegal, A.R. (2003) Mercury speciation in the San Francisco Bay estuary. Marine Chemistry 80: 199–225
M.A. Thomas, C.H. Conaway, D.J. Steding, M. Marvin-DiPasquale, K. E. Abu-Saba, A.R. Flegal
2002, Geochemistry: Exploration, Environment, Analysis (2) 211–217
2002, Geochemistry: Exploration, Environment, Analysis (2) 211–217
**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.
Science and Products
- Science
Energy Integrated Science Team
The Energy Lifecycle Integrated Science Team focuses on the potential for contaminant exposures in the environment that might originate from energy resource activities including, extraction, production, transportation, storage, extraction, waste management and restoration. Perceived health risks to humans and other organisms will be distinguished from actual risks, if any. If actual risks are...Amargosa Desert Research Site
In 1976, the U.S. Geological Survey (USGS) began studies of unsaturated zone hydrology at a site in the Amargosa Desert near Beatty, Nevada, as part of the USGS Low-Level Radioactive Waste Program. The site is near disposal trenches for civilian waste. Over the years, USGS investigations at the Amargosa Desert Research Site (ADRS) have provided long-term "benchmark" information about the hydraulic... - Data
Elemental partitioning between aqueous and solid phases of mercury and other constituents associated with Marcellus Shale Energy and Environment Laboratory (MSEEL) gas well production waste water, Morgantown, WV, 2015 - 2018.
The Marcellus Shale Energy and Environment Laboratory (MSEEL) site is a long-term field site and laboratory at the Northeast Natural Energy LLC (NNE) production facility, adjacent to the Monongahela River, located in western Monongalia County, West Virginia, USA. NNE began drilling two horizontal production wells, MIP (Morgantown Industrial Park) -5H and MIP-3H, in the Marcellus Shale in 2014. TheGeochemistry and microbiology data collected to study the effects of oil and gas wastewater dumping on arid lands in New Mexico
The Permian Basin, straddling New Mexico and Texas, is one of the most productive oil and gas (OG) provinces in the United States. OG production yields large volumes of wastewater that contain elevated concentrations of major ions including salts (also referred to as brines), and trace organic and inorganic constituents. These OG wastewaters pose unknown environmental health risks, particularly inByWater Resources Mission Area, Energy Resources Program, Environmental Health Program, Columbia Environmental Research Center, Geology, Energy & Minerals Science Center, Eastern Energy and Environmental Laboratory (EEEL), Reston Biogeochemical Processes in Groundwater Laboratory, Reston Microbiology LaboratoryGeochemistry of surface sediment and sediment cores in Bellingham Bay, Whatcom County, Washington, in February 2020
Geochemical data are reported for surface sediments and long sediment cores from Bellingham Bay, Whatcom County, Washington, collected in early February 2020 after flood conditions on the Nooksack River. Data include total organic carbon content (TOC), carbonate content (CaCO3), ratios of stable carbon 13/12 isotopes (d13C), ratios of total carbon to total nitrogen (C:N), short-lived cosmogenic raPolycyclic aromatic hydrocarbons (PAHs) and suspended sediment concentrations in the San Lorenzo River, Santa Cruz, California, USA
Water from the San Lorenzo River in Santa Cruz, California, was sampled to analyze for polycyclic aromatic hydrocarbons (PAHs) and suspended sediment concentrations (SSC) during the rainy seasons from 2008 to 2019 following drought conditions. The samples were collected using a US D-95 depth-integrated water sampler deployed from a bridge-box platform beneath a pedestrian bridge For each suspendeParent and alkylated polycyclic aromatic hydrocarbons (PAHs) and per- and polyfluoroalkyl substances (PFAS) in north San Francisco Bay, Napa River, and Sonoma Creek in 2018 and 2019
Sediment grain-size distributions, stable carbon isotope ratios (d13C), total carbon to total nitrogen ratios (C:N), short-lived radionuclides (Beryllium-7, Cesium-137, and Lead-210), concentrations of 76 parent and alkylated polycyclic aromatic hydrocarbons (PAHs) and concentrations of 33 per- and polyfluoroalkyl substances (PFAS) were measured in the northern reach of San Francisco Bay (San PablChemical characterization of water and suspended sediment of the Snake River and Hells Canyon Complex (Idaho, Oregon) (ver. 3.0, November 2023)
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: twMicrobial Carbon and Nitrogen Metabolism Across a Late Pleistocene Permafrost Chronosequence
This data release includes all of the data presented in the peer-reviewed publication "Life at the frozen limit: Microbial Carbon Metabolism Across a Late Pleistocene Permafrost Chronosequence". We collected permafrost from a Pleistocene chronosequence (19 ka to 33 ka) to examine (1) changes in the functional genetic potential of extant microbial communities to metabolize polysaccharides, (2) shifSediment Mercury Profile, Laguna de Pozuelos, Argentine Northwest
The data represent a shallow mercury chronology using sediment core from a playa lake system situated in a high-altitude setting in northwest Argentina. Archive samples were used from sediment core (LP07-1A) that was collected from a location (lat -22.362100, lon -66.003600) in the center of the playa-lake Laguna de Pozuelos in the dry season of 2007, when the water level was 2 to 3 cm. The samplePermafrost Mapping in Two Wetland Systems North of the Tanana River in Interior Alaska 2014
Surface-based 2D electrical resistivity tomography (ERT) surveys were used to investigate the distribution of permafrost at wetland sites on the alluvial plain north of the Tanana River, 20 km southwest of Fairbanks, Alaska, in June and September 2014. The sites contained habitat types characteristic of interior Alaska, including thermokarst bog, forested permafrost plateau, and a rich fen. TheseData for Biogeochemical and Physical Processes Controlling Mercury Methylation and Bioaccumulation in Lake Powell, Glen Canyon National Recreation Area, Utah and Arizona
This dataset includes the field measurements and laboratory analyses of surface water, seston, and sediment collected from Lake Powell, within Glen Canyon National Recreation area (GLCA), during high flow (May-June 2014) and low flow (August 2015) conditions. The study area includes 12-13 sampling sites that follow a transect spanning the entire length of the reservoir from the Colorado River infl - Publications
Filter Total Items: 23
Knowledge gaps and opportunities in water-quality drivers of aquatic ecosystem health
This report identifies key scientific gaps that limit our ability to predict water quality effects on health of aquatic ecosystems and proposes approaches to address those gaps. Topics considered include (1) coupled nutrient-carbon cycle processes and related ecological-flow-regime drivers of ecosystem health, (2) anthropogenic and geogenic toxin bioexposure, (3) fine sediment drivers of aquatic eKnowledge gaps and opportunities for understanding water-quality processes affecting water availability for beneficial uses
This report describes scientific gaps that limit our ability to predict water-quality effects on water availability for beneficial uses across the United States. Water-quality constituents considered in the report include salinity, geogenic constituents, contaminants of emerging concern, and nitrogen. For each constituent, there is a selection of scientific gaps, approaches, and outcomes to help gExamining terrestrial and subterranean sediment sources and transport processes in an urban sewershed with an entirely buried stream network, Washington, D.C., United States
Excessive fine-grained sediment runoff due to anthropogenic activities is a major environmental concern for watersheds worldwide, especially so for urban areas such as Washington, D.C. Dated grey infrastructure, i.e., the network of buried pipes and reservoirs managing water resources, can amplify existing issues with sediment runoff and associated pollutants. This infrastructure, which is generalAuthorsZachary Clifton, Allen C. Gellis, Leah Ellen Staub, Matt J. Cashman, Christopher H. Conaway, Cecilia Lane, David PilatMechanisms for retention of low molecular weight organic carbon varies with soil depth at a coastal prairie ecosystem
Though primary sources of carbon (C) to soil are plant inputs (e.g., rhizodeposits), the role of microorganisms as mediators of soil organic carbon (SOC) retention is increasingly recognized. Yet, insufficient knowledge of sub-soil processes complicates attempts to describe microbial-driven C cycling at depth as most studies of microbial-mineral-C interactions focus on surface horizons. We leveragAuthorsJack McFarland, Corey Lawrence, Courtney Creamer, Marjorie S. Schulz, Christopher H. Conaway, Sara Peek, Mark Waldrop, Sabrina N. Sevilgen, Monica HawPermafrost mapping with electrical resistivity tomography in two wetland systems north of the Tanana River, Interior Alaska
Surface-based 2D electrical resistivity tomography (ERT) surveys were used to characterize permafrost distribution at wetland sites on the alluvial plain north of the Tanana River, 20 km southwest of Fairbanks, Alaska, in June and September 2014. The sites were part of an ecologically-sensitive research area characterizing biogeochemical response of this region to warming and permafrost thaw, andAuthorsChristopher H. Conaway, Cordell Johnson, Thomas Lorenson, Merritt R. Turetsky, Eugénie S. Euskirchen, Mark Waldrop, Peter W. SwarzenskiLife at the frozen limit: Microbial carbon metabolism across a Late Pleistocene permafrost chronosequence
Permafrost is an extreme habitat yet it hosts microbial populations that remain active over millennia. Using permafrost collected from a Pleistocene chronosequence (19 to 33 ka), we hypothesized that the functional genetic potential of microbial communities in permafrost would reflect microbial strategies to metabolize permafrost soluble organic matter (OM) in situ over geologic time. We also hypoAuthorsMary-Cathrine Leewis, Renaud Berlemont, David C. Podgorski, Archana Srinivas, Phoebe Zito, Robert G. M. Spencer, Jack McFarland, Thomas A. Douglas, Christopher H. Conaway, Mark Waldrop, Rachel MackelprangChemical composition of formation water in shale and tight reservoirs: A basin-scale perspective
No abstract available.AuthorsYousif Kharaka, Kathleen Gans, Elisabeth Rowan, James Thordsen, Christopher H. Conaway, Madalyn S. Blondes, Mark A. EngleSpatial fingerprinting of biogenic and anthropogenic volatile organic compounds in an arid unsaturated zone
Subsurface volatile organic compounds (VOCs) can pose risks to human and environmental health and mediate biological processes. VOCs have both anthropogenic and biogenic origins, but the relative importance of these sources has not been explored in subsurface environments. This study synthesizes 17 years of VOC data from the Amargosa Desert Research Site (ADRS) with the goal of improving understanAuthorsChristopher Green, Wentai Luo, Christopher H. Conaway, Karl B. Haase, Ronald J. Baker, Brian J. AndraskiBiogeochemical and physical processes controlling mercury methylation and bioaccumulation in Lake Powell, Glen Canyon National Recreation Area, Utah and Arizona, 2014 and 2015
Mercury monitoring results from about 300 Morone saxatilis (striped bass) muscle tissue samples collected by the State of Utah from Lake Powell resulted in a Utah/Arizona fish consumption advisory issued in 2012 for approximately the lower 100 kilometers of the reservoir. Chemical, physical, and biological data were collected during two synoptic sampling cruises on Lake Powell during May/June 2014AuthorsDavid L. Naftz, Mark Marvin-DiPasquale, David P. Krabbenhoft, George Aiken, Eric S. Boyd, Christopher H. Conaway, Jacob M. Ogorek, Gregory M. AndersonUnsaturated zone CO2, CH4, and δ13C-CO2 at an arid region low-level radioactive waste disposal site
Elevated tritium, radiocarbon, Hg, and volatile organic compounds associated with low-level radioactive waste (LLRW) at the USGS Amargosa Desert Research Site (ADRS) have stimulated research on factors and processes that affect contaminant gas distribution and transport. Consequently, we examined the sources, mixing, and biogeochemistry of CO2 and CH4, two additional important species in the unsatAuthorsChristopher H. Conaway, Michelle Ann Walvoord, Randall B. Thomas, Christopher Green, R.J. Baker, James J. Thordsen, David A. Stonestrom, Brian J. AndraskiA regime shift in sediment export from a coastal watershed during a record wet winter, California: Implications for landscape response to hydroclimatic extremes
Small, steep watersheds are prolific sediment sources from which sediment flux is highly sensitive to climatic changes. Storm intensity and frequency are widely expected to increase during the 21st century, and so assessing the response of small, steep watersheds to extreme rainfall is essential to understanding landscape response to climate change. During record winter rainfall in 2016–2017, theAuthorsAmy E. East, Andrew W. Stevens, Andrew C. Ritchie, Patrick L. Barnard, Pamela L. Campbell‐Swarzenski, Brian D. Collins, Christopher H. ConawayMicrobial survival strategies in ancient permafrost: insights from metagenomics
In permafrost (perennially frozen ground) microbes survive oligotrophic conditions, sub-zero temperatures, low water availability and high salinity over millennia. Viable life exists in permafrost tens of thousands of years old but we know little about the metabolic and physiological adaptations to the challenges presented by life in frozen ground over geologic time. In this study we asked whetherAuthorsRachel Mackelprang, Alexander Burkert, Monica Haw, Tara Mahendrarajah, Christopher H. Conaway, Thomas A. Douglas, Mark P. WaldropNon-USGS Publications**
Flegal, A.R., Gallon, C., Ganguli, P.M., and Conaway, C.H. (2013) All the Lead in China. Critical Reviews in Environmental Science and Technology 43: 1869–1944Gallon, C, Ranville, M.A., Conaway, C.H., Landing, W., Buck, C., Morton, P., and Flegal, A.R. (2011) Asian industrial lead inputs to the North Pacific evidenced by lead concentrations and isotopic compositions in surface waters and aerosols. Environmental Science & Technology 45(23):9874–9882Conaway, C.H., Black, F.J., Weiss-Penzias, P., Gault-Ringold, M., and Flegal, A.R. (2010) Mercury speciation in Pacific coastal rainwater, Monterey Bay, California. Atmospheric Environment 44(14): 1788–1797Black, F.J., Conaway, C.H., and Flegal, A.R. (2009) Stability of dimethyl mercury in seawater and its conversion to monomethyl mercury. Environmental Science & Technology 43(11): 4056–4062Conaway, C.H., Black, F.J., Gault-Ringold, M., Pennington, J.T., Chavez, F.P., and Flegal, A.R. (2009) Dimethylmercury in coastal upwelling waters, Monterey Bay, California. Environmental Science & Technology 43(5): 1305–1309N. David, L.J. McKee, F.J. Black, A.R. Flegal, C.H. Conaway, D.H. Schoellhamer, N.K. Ganju
2009, Environmental Toxicology and Chemistry (28) 2091–2100Conaway, C.H., Black, F.J., Grieb, T.M, Roy, S., and Flegal, A.R. (2008) Mercury in the San Francisco Estuary. Reviews of Environmental Contamination and Toxicology 194: 29–54Conaway, C.H., Ross, J.R.M., Looker, R., Mason, R.P., and Flegal, A.R. (2007) Decadal mercury trends in San Francisco Estuary sediments. Environmental Research 105(1): 53–66Conaway, C.H., Pride D.E., Faure, G., and Tettenhorst, R.T. (2005) Mineralogical and geochemical investigation of sediment in the Snake River arm of the Dillon Reservoir, Summit County, Colorado. Lakes and Reservoirs: Research and Management 10: 235–242Conaway, C.H., Mason, R.P., Steding, D.J., and Flegal, A.R. (2005) Estimate of mercury emission from gasoline and diesel fuel consumption, San Francisco Bay area, California. Atmospheric Environment 39(1): 101–105Flegal, A.R., Conaway, C.H., Scelfo, G.M., Hibdon, S., Sañudo-Wilhelmy, S.A. (2005) Factors influencing measurements of decadal variations in metal contamination in San Francisco Bay, California. Ecotoxicolgy 14(6): 645–660Conaway, C.H., Watson, E. Flanders, J.R., and Flegal, A.R. (2004) Mercury deposition in a tidal marsh of south San Francisco Bay downstream of the historic New Almaden mining district, California. Marine Chemistry 90(1–4): 175–184Conaway, C.H., Squire, S., Mason, R.P., and Flegal, A.R. (2003) Mercury speciation in the San Francisco Bay estuary. Marine Chemistry 80: 199–225M.A. Thomas, C.H. Conaway, D.J. Steding, M. Marvin-DiPasquale, K. E. Abu-Saba, A.R. Flegal
2002, Geochemistry: Exploration, Environment, Analysis (2) 211–217**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.
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