U.S. Geological Survey (USGS) scientists prepare a tracer solution to conduct a natural gradient tracer test to measure anammox activity in groundwater. The tracer solution is prepared by pumping groundwater into a gas impermeable bladder to maintain the in situ dissolved oxygen concentration and then mixing in the tracer chemicals.
Deborah Repert
Deb Repert is a Microbiologist for the USGS Water Resources Mission Area.
Deb Repert has worked with the USGS since 1998 as a microbiologist focusing on nitrogen cycling processes in aquatic environments. She is interested in the physical, chemical and microbiological processes controlling the transport and fate of nutrients in both pristine and contaminated environments.
She received an undergraduate degree in Biology from Clarkson University and a Master's degree in Zoology with an emphasis in microbiology and stream ecology from Michigan State University.
Education
M.S. - Zoology, emphasis in microbiology and stream ecology, Michigan State University, 1992
B.S. - Biology, Clarkson University, 1988
Employment
Microbiologist, National Research Program, US Geological Survey, Boulder, CO, 1998-present
Research Technician, The Louis Calder Center, Fordham University, Armonk, NY, 1993-1997
Stream Research Coordinator, Arctic LTER Project, The Ecosystems Center, Marine Biological Laboratory, Woods Hole, MA ,1992-1993
Laboratory Technician, Clarkson University, Potsdam, NY, 1988-1989
Science and Products
Filter Total Items: 19
Data from laboratory experiments to assess seasonal carbon, nitrogen, and phosphorus processing in water and sediments from the Illinois River near Starved Rock Lock and Dam, 2022.
Data on carbon and nutrient processing in key locations and over seasonal time scales can provide critical information about the concentrations and potential utilization rates of bioavailable constituents that are known to have a role in cyanobacteria harmful algal blooms (cyanoHABs). Laboratory experiments were performed to measure seasonal nutrient processing rates of carbon, nitrogen...
Biogeochemical Data from Field Samples and Laboratory Experiments, Boulder Creek Watershed, Colorado (2019-2023)
Biogeochemical processes are key drivers of chemical solubility and mobilization. Understanding these processes will lead to improved predictive capabilities and may aid with watershed management decisions. This data release presents results from the Boulder Creek, Colorado watershed, including analyses of water and sediment. From April to August 2019, water samples were collected weekly...
Water chemistry data observed in experimental laboratory mesocosms exposed to different nitrapyrin and nitrogen amendments in the presence or absence of a nitrifier enriched microbial (NEM) community
These data describe the results of a controlled laboratory mesocosm experiment evaluating the effect of nitrapyrin, a nitrification inhibitor, on nitrification in a nitrifier enriched microbial (NEM) community. Parameters described include the water chemistry and nitrapyrin measurement results of experimental mesocosms. Microbial community data is described in a separate data release.
Water-Quality Data in and near Groundwater Flow-Through Kettle-Hole Lakes, Western Cape Cod, Massachusetts, 2003 - 2018
This U.S. Geological Survey (USGS) data release provides a comprehensive dataset of water-quality results, physical-parameter measurements, hydrologic measurements, and site information collected to study the nature and extent of water quality along groundwater flow paths adjacent to glacial-kettle lakes on Cape Cod, Massachusetts. Water-quality samples were collected in 2003, 2005, and...
Biological N-cycling data from soils collected along an elevation gradient in the CO Front Range (2018-2019) (ver. 2.0, November 2024)
Atmospheric deposition of reactive nitrogen (Nr) can impact the soil microbial community structure and function and thus ecosystem processing and export of nutrients. Ecosystem response to atmospheric inputs of nitrogen depends on several factors, including elevational climate conditions (freeze/thaw cycles, precipitation), geology, soil and vegetation type, N speciation and microbial...
Seasonal Atmospheric Nitrate and Ammonium Deposition along an Elevation Gradient in the Colorado Front Range using Ion Exchange Resin Columns (2018-2019)
Atmospheric deposition of reactive nitrogen (Nr) due to human activities can have measurable effects on ecosystem processing and export of nutrients, groundwater and surface-water quality. Rates of Nr deposition to lower-elevation forests immediately adjacent to the Denver/Boulder urban area, however, have only recently been measured. The focus of this study was to determine the extent...
Concentrations of Per- and Polyfluoroalkyl Substances (PFAS) in Lake-Bottom Sediments of Ashumet Pond on Cape Cod, Massachusetts, 2020 (ver. 2.0, February 2024)
Lake-bottom sediment and associated quality-control samples were collected in August 2020 from one coring location (U.S. Geological Survey station 413756070321301, ASHUMET POND, MASHPEE MI-ASHPD-0011) in Ashumet Pond downgradient from a former fire-training area on Cape Cod, Massachusetts. The core was collected to determine if per- and polyfluoroalkyl substances (PFAS) were present in...
Diel and synoptic sampling data from Boulder Creek and South Boulder Creek, near Boulder, Colorado, September–October 2019
Multiple sampling campaigns were conducted near Boulder, Colorado, to quantify constituent concentrations and loads in Boulder Creek and its tributary, South Boulder Creek. Diel sampling was initiated at approximately 1100 hours on September 17, 2019, and continued until approximately 2300 hours on September 18, 2019. During this time period, samples were collected at two locations on...
Water-Chemistry and Isotope Data for Selected Springs, Geysers, Streams, and Rivers in Yellowstone National Park, Wyoming (ver. 2.0, March 2025)
There are over 10,000 hydrothermal features in Yellowstone National Park (YNP), where waters have pH values ranging from about 1 to 10 and surface temperatures up to 95 °C. Active hydrothermal areas in YNP provide insight into a variety of processes occurring at depth, such as water-rock and oxidation-reduction (redox) reactions, the formation of alteration minerals, and microbial...
Temporal Viral Viability Data from Avian Influenza A Viruses Maintained in Alaska Wetlands Under Experimental and Environmental Conditions
Data sets containing: (1) sample collection and influenza A virus (IAV) screening information for wild ducks, (2) water temperature data from four wetlands within the Izembek National Wildlife Refuge in Alaska, USA (3) water quality measurement from four wetlands within the Izembek National Wildlife Refuge in Alaska, USA, (4) genetic sequence data for IAVs recovered from replicate...
Chemical Data From 40 Years of Monitoring a Treated-Wastewater Groundwater Plume in a Sand and Gravel Aquifer, Cape Cod, Massachusetts, 1978-2018 (ver. 1.1, April 2025)
This U.S. Geological Survey data release provides a comprehensive dataset of water-quality data and sampling-site characteristics collected in 1978–2018 during a study of the effects of land disposal of treated wastewater on groundwater quality in an unconsolidated sand and gravel aquifer on Cape Cod, Massachusetts. Treated sewage-derived wastewater was discharged to rapid-infiltration...
Microbial Community and N-cycling gene abundance from Ponds and Groundwater on Cape Cod, MA (2015 - 2018)
Surface water, pore water, pond bottom sediments, and groundwater were sampled within and downgradient from five groundwater flow-through ponds that ranged from oligotrophic to eutrophic in Cape Cod, Massachusetts during different seasons from 2015 – 2018. The sampled ponds included Ashumet, Santuit, Snake, Shubael, and Longs. Pore water was collected between 15 to 100 cm below the pond...
U.S. Geological Survey scientists prepare a tracer solution
U.S. Geological Survey scientists prepare a tracer solution
U.S. Geological Survey (USGS) scientists prepare a tracer solution to conduct a natural gradient tracer test to measure anammox activity in groundwater. The tracer solution is prepared by pumping groundwater into a gas impermeable bladder to maintain the in situ dissolved oxygen concentration and then mixing in the tracer chemicals.
Filter Total Items: 24
Relationship of atmospheric nitrogen deposition to soil nitrogen cycling along an elevation gradient in the Colorado Front Range
Microbial processing of atmospheric nitrogen (N) deposition regulates the retention and mobilization of N in soils, with important implications for water quality. Understanding the links between N deposition, microbial communities, N transformations, and water quality is critical as N deposition shifts toward reduced N and remains persistently high in many regions. Here, we investigated...
Authors
Deborah A. Repert, Ruth C. Heindel, Sheila F. Murphy, Kaitlyn M. Jeanis
Influence of four veterinary antibiotics on constructed treatment wetland nitrogen transformation
The use of wetlands as a treatment approach for nitrogen in runoff is a common practice in agroecosystems. However, nitrate is not the sole constituent present in agricultural runoff and other biologically active contaminants have the potential to affect nitrate removal efficiency. In this study, the impacts of the combined effects of four common veterinary antibiotics (chlortetracycline...
Authors
Matthew V. Russell, Tiffany L. Messer, Deborah A. Repert, Richard L. Smith, Shannon Bartelt-Hunt, Daniel D. Snow, Ariel P. Reed
Spatial, seasonal, and diel controls of nitrogen-carbon-oxygen cycling during lake-water infiltration to an aquifer
Many freshwater lakes are groundwater flow-through systems. Although lakes commonly are considered to be sinks for nitrogen inputs, relatively little is known about carbon and nitrogen export from lakes to groundwater. The current study focused on lake-bottom biogeochemical processes accompanying the transport of nitrogen, dissolved oxygen (O2), and dissolved organic carbon (DOC) during...
Authors
Richard L. Smith, Deborah A. Repert, Jennifer C. Underwood, J.K. Böhlke, Denis R. LeBlanc, Robert B. Hull, Douglas B. Kent, Ariel P. Reed, Stanley J. Mroczkowski
Urbanization and water management control stream water quality along a mountain to plains transition
Urbanization can have substantial effects on water quality due to altered hydrology and introduction of constituents to water bodies. In arid and semi-arid environments, streams are further stressed by dewatering as a result of diversions. We conducted a high-resolution synoptic survey of two streams in Colorado, USA that transition abruptly from granitic/metamorphic forested mountains...
Authors
Sheila F. Murphy, Robert L. Runkel, Edward G. Stets, Alex J Nolan, Deborah A. Repert
Elevated nitrogen deposition to fire-prone forests adjacent to urban and agricultural areas, Colorado front range, USA
As humans increasingly dominate the nitrogen cycle, deposition of reactive nitrogen (Nr) will continue to have adverse consequences for ecosystems. In the Rocky Mountains, Nr deposition remains elevated and has become increasingly dominated by ammonium, despite efforts to reduce emissions. Currently, spatial models of Nr deposition do not fully account for urban and agricultural...
Authors
Ruth C. Heindel, Sheila F. Murphy, Deborah A. Repert, Gregory A. Wetherbee, Alexander Liethen, David Clow, Toby A. Halamka
Evidence for interannual persistence of infectious influenza A viruses in Alaska wetlands
Influenza A viruses (IAVs) deposited by wild birds into the environment may lead to sporadic mortality events and economically costly outbreaks among domestic birds. There is a paucity of information, however, regarding the persistence of infectious IAVs within the environment following deposition. In this investigation, we assessed the persistence of 12 IAVs that were present in the...
Authors
Andrew M. Ramey, Andrew B. Reeves, Benjamin Joel Lagassé, Vijay P. Patil, Laura E. Hubbard, Dana W. Kolpin, R. Blaine McCleskey, Deborah A. Repert, David E. Stallknecht, Rebecca L. Poulson
Nitrogen biogeochemistry in a boreal headwater stream network in interior Alaska
High latitude, boreal watersheds are nitrogen (N)-limited ecosystems that export large amounts of organic carbon (C). Key controls on C cycling in these environments are the biogeochemical processes affecting the N cycle. A study was conducted in Nome Creek, an upland headwater tributary of the Yukon River, and two first-order tributaries to Nome Creek, to examine the relation between...
Authors
Richard L. Smith, Deborah A. Repert, Joshua C. Koch
Atmospheric dust deposition varies by season and elevation in the Colorado Front Range, USA
As atmospheric dust deposition continues to increase across the southwestern United States, it has the potential to alter ecosystem productivity and structure by delivering nutrients, base cations, and pollutants to remote mountain sites. Due to the sparse distribution of dust monitoring sites, open questions remain about the spatial and temporal variability of dust fluxes and...
Authors
Ruth C. Heindel, Annie L. Putman, Sheila F. Murphy, Deborah A. Repert, Eve-Lyn S. Hinckley
Reactive transport modeling to understand attenuation of arsenic concentrations in anoxic groundwater during Fe(II) oxidation by nitrate
A previously published field-experimental investigation showed that injection of nitrate in anoxic groundwater that contained aqueous and sediment-bound Fe(II) diminished concentrations of As(V) and As(III) to below drinking-water limits. In the current study, reactive transport modeling confirmed that the observed attenuation was consistent with oxidation of Fe(II) by nitrate, leading...
Authors
Douglas B. Kent, Richard L. Smith, James Jamieson, J.K. Böhlke, Deborah A. Repert, Henning Prommer
Seasonal and spatial variation in the location and reactivity of a nitrate-contaminated groundwater discharge zone in a lakebed
Groundwater discharge delivering anthropogenic N from surrounding watersheds can impact lake nutrient budgets. However, upgradient groundwater processes and changing dynamics in N biogeochemistry at the groundwater-lake interface are complex and difficult to resolve. In this study, hydrograph variations in a groundwater flow-through lake altered discharge patterns of a wastewater-derived...
Authors
Richard L. Smith, Deborah A. Repert, Deborah Stoliker, Douglas B. Kent, Bongkeun Song, Denis R. LeBlanc, Timothy McCobb, J.K. Böhlke, Sung Pil Hyun, Hee Sun Moon
Anoxic nitrate reduction coupled with iron oxidation and attenuation of dissolved arsenic and phosphate in a sand and gravel aquifer
Nitrate has become an increasingly abundant potential electron acceptor for Fe(II) oxidation in groundwater, but this redox couple has not been well characterized within aquifer settings. To investigate this reaction and some of its implications for redox-sensitive groundwater contaminants, we conducted an in situ field study in a wastewater-contaminated aquifer on Cape Cod. Long-term...
Authors
Richard L. Smith, Douglas B. Kent, Deborah A. Repert, J.K. Böhlke
Hydrologic controls on nitrogen cycling processes and functional gene abundance in sediments of a groundwater flow-through lake
The fate and transport of inorganic nitrogen (N) is a critically important issue for human and aquatic ecosystem health because discharging N-contaminated groundwater can foul drinking water and cause algal blooms. Factors controlling N-processing were examined in sediments at three sites with contrasting hydrologic regimes at a lake on Cape Cod, MA. These factors included water...
Authors
Deborah Stoliker, Deborah A. Repert, Richard L. Smith, Bongkeun Song, Denis R. LeBlanc, Timothy McCobb, Christopher Conaway, Sung Pil Hyun, Dong-Chan Koh, Hee Sun Moon, Douglas B. Kent
Science and Products
Filter Total Items: 19
Data from laboratory experiments to assess seasonal carbon, nitrogen, and phosphorus processing in water and sediments from the Illinois River near Starved Rock Lock and Dam, 2022.
Data on carbon and nutrient processing in key locations and over seasonal time scales can provide critical information about the concentrations and potential utilization rates of bioavailable constituents that are known to have a role in cyanobacteria harmful algal blooms (cyanoHABs). Laboratory experiments were performed to measure seasonal nutrient processing rates of carbon, nitrogen...
Biogeochemical Data from Field Samples and Laboratory Experiments, Boulder Creek Watershed, Colorado (2019-2023)
Biogeochemical processes are key drivers of chemical solubility and mobilization. Understanding these processes will lead to improved predictive capabilities and may aid with watershed management decisions. This data release presents results from the Boulder Creek, Colorado watershed, including analyses of water and sediment. From April to August 2019, water samples were collected weekly...
Water chemistry data observed in experimental laboratory mesocosms exposed to different nitrapyrin and nitrogen amendments in the presence or absence of a nitrifier enriched microbial (NEM) community
These data describe the results of a controlled laboratory mesocosm experiment evaluating the effect of nitrapyrin, a nitrification inhibitor, on nitrification in a nitrifier enriched microbial (NEM) community. Parameters described include the water chemistry and nitrapyrin measurement results of experimental mesocosms. Microbial community data is described in a separate data release.
Water-Quality Data in and near Groundwater Flow-Through Kettle-Hole Lakes, Western Cape Cod, Massachusetts, 2003 - 2018
This U.S. Geological Survey (USGS) data release provides a comprehensive dataset of water-quality results, physical-parameter measurements, hydrologic measurements, and site information collected to study the nature and extent of water quality along groundwater flow paths adjacent to glacial-kettle lakes on Cape Cod, Massachusetts. Water-quality samples were collected in 2003, 2005, and...
Biological N-cycling data from soils collected along an elevation gradient in the CO Front Range (2018-2019) (ver. 2.0, November 2024)
Atmospheric deposition of reactive nitrogen (Nr) can impact the soil microbial community structure and function and thus ecosystem processing and export of nutrients. Ecosystem response to atmospheric inputs of nitrogen depends on several factors, including elevational climate conditions (freeze/thaw cycles, precipitation), geology, soil and vegetation type, N speciation and microbial...
Seasonal Atmospheric Nitrate and Ammonium Deposition along an Elevation Gradient in the Colorado Front Range using Ion Exchange Resin Columns (2018-2019)
Atmospheric deposition of reactive nitrogen (Nr) due to human activities can have measurable effects on ecosystem processing and export of nutrients, groundwater and surface-water quality. Rates of Nr deposition to lower-elevation forests immediately adjacent to the Denver/Boulder urban area, however, have only recently been measured. The focus of this study was to determine the extent...
Concentrations of Per- and Polyfluoroalkyl Substances (PFAS) in Lake-Bottom Sediments of Ashumet Pond on Cape Cod, Massachusetts, 2020 (ver. 2.0, February 2024)
Lake-bottom sediment and associated quality-control samples were collected in August 2020 from one coring location (U.S. Geological Survey station 413756070321301, ASHUMET POND, MASHPEE MI-ASHPD-0011) in Ashumet Pond downgradient from a former fire-training area on Cape Cod, Massachusetts. The core was collected to determine if per- and polyfluoroalkyl substances (PFAS) were present in...
Diel and synoptic sampling data from Boulder Creek and South Boulder Creek, near Boulder, Colorado, September–October 2019
Multiple sampling campaigns were conducted near Boulder, Colorado, to quantify constituent concentrations and loads in Boulder Creek and its tributary, South Boulder Creek. Diel sampling was initiated at approximately 1100 hours on September 17, 2019, and continued until approximately 2300 hours on September 18, 2019. During this time period, samples were collected at two locations on...
Water-Chemistry and Isotope Data for Selected Springs, Geysers, Streams, and Rivers in Yellowstone National Park, Wyoming (ver. 2.0, March 2025)
There are over 10,000 hydrothermal features in Yellowstone National Park (YNP), where waters have pH values ranging from about 1 to 10 and surface temperatures up to 95 °C. Active hydrothermal areas in YNP provide insight into a variety of processes occurring at depth, such as water-rock and oxidation-reduction (redox) reactions, the formation of alteration minerals, and microbial...
Temporal Viral Viability Data from Avian Influenza A Viruses Maintained in Alaska Wetlands Under Experimental and Environmental Conditions
Data sets containing: (1) sample collection and influenza A virus (IAV) screening information for wild ducks, (2) water temperature data from four wetlands within the Izembek National Wildlife Refuge in Alaska, USA (3) water quality measurement from four wetlands within the Izembek National Wildlife Refuge in Alaska, USA, (4) genetic sequence data for IAVs recovered from replicate...
Chemical Data From 40 Years of Monitoring a Treated-Wastewater Groundwater Plume in a Sand and Gravel Aquifer, Cape Cod, Massachusetts, 1978-2018 (ver. 1.1, April 2025)
This U.S. Geological Survey data release provides a comprehensive dataset of water-quality data and sampling-site characteristics collected in 1978–2018 during a study of the effects of land disposal of treated wastewater on groundwater quality in an unconsolidated sand and gravel aquifer on Cape Cod, Massachusetts. Treated sewage-derived wastewater was discharged to rapid-infiltration...
Microbial Community and N-cycling gene abundance from Ponds and Groundwater on Cape Cod, MA (2015 - 2018)
Surface water, pore water, pond bottom sediments, and groundwater were sampled within and downgradient from five groundwater flow-through ponds that ranged from oligotrophic to eutrophic in Cape Cod, Massachusetts during different seasons from 2015 – 2018. The sampled ponds included Ashumet, Santuit, Snake, Shubael, and Longs. Pore water was collected between 15 to 100 cm below the pond...
U.S. Geological Survey scientists prepare a tracer solution
U.S. Geological Survey scientists prepare a tracer solution
U.S. Geological Survey (USGS) scientists prepare a tracer solution to conduct a natural gradient tracer test to measure anammox activity in groundwater. The tracer solution is prepared by pumping groundwater into a gas impermeable bladder to maintain the in situ dissolved oxygen concentration and then mixing in the tracer chemicals.
U.S. Geological Survey (USGS) scientists prepare a tracer solution to conduct a natural gradient tracer test to measure anammox activity in groundwater. The tracer solution is prepared by pumping groundwater into a gas impermeable bladder to maintain the in situ dissolved oxygen concentration and then mixing in the tracer chemicals.
Filter Total Items: 24
Relationship of atmospheric nitrogen deposition to soil nitrogen cycling along an elevation gradient in the Colorado Front Range
Microbial processing of atmospheric nitrogen (N) deposition regulates the retention and mobilization of N in soils, with important implications for water quality. Understanding the links between N deposition, microbial communities, N transformations, and water quality is critical as N deposition shifts toward reduced N and remains persistently high in many regions. Here, we investigated...
Authors
Deborah A. Repert, Ruth C. Heindel, Sheila F. Murphy, Kaitlyn M. Jeanis
Influence of four veterinary antibiotics on constructed treatment wetland nitrogen transformation
The use of wetlands as a treatment approach for nitrogen in runoff is a common practice in agroecosystems. However, nitrate is not the sole constituent present in agricultural runoff and other biologically active contaminants have the potential to affect nitrate removal efficiency. In this study, the impacts of the combined effects of four common veterinary antibiotics (chlortetracycline...
Authors
Matthew V. Russell, Tiffany L. Messer, Deborah A. Repert, Richard L. Smith, Shannon Bartelt-Hunt, Daniel D. Snow, Ariel P. Reed
Spatial, seasonal, and diel controls of nitrogen-carbon-oxygen cycling during lake-water infiltration to an aquifer
Many freshwater lakes are groundwater flow-through systems. Although lakes commonly are considered to be sinks for nitrogen inputs, relatively little is known about carbon and nitrogen export from lakes to groundwater. The current study focused on lake-bottom biogeochemical processes accompanying the transport of nitrogen, dissolved oxygen (O2), and dissolved organic carbon (DOC) during...
Authors
Richard L. Smith, Deborah A. Repert, Jennifer C. Underwood, J.K. Böhlke, Denis R. LeBlanc, Robert B. Hull, Douglas B. Kent, Ariel P. Reed, Stanley J. Mroczkowski
Urbanization and water management control stream water quality along a mountain to plains transition
Urbanization can have substantial effects on water quality due to altered hydrology and introduction of constituents to water bodies. In arid and semi-arid environments, streams are further stressed by dewatering as a result of diversions. We conducted a high-resolution synoptic survey of two streams in Colorado, USA that transition abruptly from granitic/metamorphic forested mountains...
Authors
Sheila F. Murphy, Robert L. Runkel, Edward G. Stets, Alex J Nolan, Deborah A. Repert
Elevated nitrogen deposition to fire-prone forests adjacent to urban and agricultural areas, Colorado front range, USA
As humans increasingly dominate the nitrogen cycle, deposition of reactive nitrogen (Nr) will continue to have adverse consequences for ecosystems. In the Rocky Mountains, Nr deposition remains elevated and has become increasingly dominated by ammonium, despite efforts to reduce emissions. Currently, spatial models of Nr deposition do not fully account for urban and agricultural...
Authors
Ruth C. Heindel, Sheila F. Murphy, Deborah A. Repert, Gregory A. Wetherbee, Alexander Liethen, David Clow, Toby A. Halamka
Evidence for interannual persistence of infectious influenza A viruses in Alaska wetlands
Influenza A viruses (IAVs) deposited by wild birds into the environment may lead to sporadic mortality events and economically costly outbreaks among domestic birds. There is a paucity of information, however, regarding the persistence of infectious IAVs within the environment following deposition. In this investigation, we assessed the persistence of 12 IAVs that were present in the...
Authors
Andrew M. Ramey, Andrew B. Reeves, Benjamin Joel Lagassé, Vijay P. Patil, Laura E. Hubbard, Dana W. Kolpin, R. Blaine McCleskey, Deborah A. Repert, David E. Stallknecht, Rebecca L. Poulson
Nitrogen biogeochemistry in a boreal headwater stream network in interior Alaska
High latitude, boreal watersheds are nitrogen (N)-limited ecosystems that export large amounts of organic carbon (C). Key controls on C cycling in these environments are the biogeochemical processes affecting the N cycle. A study was conducted in Nome Creek, an upland headwater tributary of the Yukon River, and two first-order tributaries to Nome Creek, to examine the relation between...
Authors
Richard L. Smith, Deborah A. Repert, Joshua C. Koch
Atmospheric dust deposition varies by season and elevation in the Colorado Front Range, USA
As atmospheric dust deposition continues to increase across the southwestern United States, it has the potential to alter ecosystem productivity and structure by delivering nutrients, base cations, and pollutants to remote mountain sites. Due to the sparse distribution of dust monitoring sites, open questions remain about the spatial and temporal variability of dust fluxes and...
Authors
Ruth C. Heindel, Annie L. Putman, Sheila F. Murphy, Deborah A. Repert, Eve-Lyn S. Hinckley
Reactive transport modeling to understand attenuation of arsenic concentrations in anoxic groundwater during Fe(II) oxidation by nitrate
A previously published field-experimental investigation showed that injection of nitrate in anoxic groundwater that contained aqueous and sediment-bound Fe(II) diminished concentrations of As(V) and As(III) to below drinking-water limits. In the current study, reactive transport modeling confirmed that the observed attenuation was consistent with oxidation of Fe(II) by nitrate, leading...
Authors
Douglas B. Kent, Richard L. Smith, James Jamieson, J.K. Böhlke, Deborah A. Repert, Henning Prommer
Seasonal and spatial variation in the location and reactivity of a nitrate-contaminated groundwater discharge zone in a lakebed
Groundwater discharge delivering anthropogenic N from surrounding watersheds can impact lake nutrient budgets. However, upgradient groundwater processes and changing dynamics in N biogeochemistry at the groundwater-lake interface are complex and difficult to resolve. In this study, hydrograph variations in a groundwater flow-through lake altered discharge patterns of a wastewater-derived...
Authors
Richard L. Smith, Deborah A. Repert, Deborah Stoliker, Douglas B. Kent, Bongkeun Song, Denis R. LeBlanc, Timothy McCobb, J.K. Böhlke, Sung Pil Hyun, Hee Sun Moon
Anoxic nitrate reduction coupled with iron oxidation and attenuation of dissolved arsenic and phosphate in a sand and gravel aquifer
Nitrate has become an increasingly abundant potential electron acceptor for Fe(II) oxidation in groundwater, but this redox couple has not been well characterized within aquifer settings. To investigate this reaction and some of its implications for redox-sensitive groundwater contaminants, we conducted an in situ field study in a wastewater-contaminated aquifer on Cape Cod. Long-term...
Authors
Richard L. Smith, Douglas B. Kent, Deborah A. Repert, J.K. Böhlke
Hydrologic controls on nitrogen cycling processes and functional gene abundance in sediments of a groundwater flow-through lake
The fate and transport of inorganic nitrogen (N) is a critically important issue for human and aquatic ecosystem health because discharging N-contaminated groundwater can foul drinking water and cause algal blooms. Factors controlling N-processing were examined in sediments at three sites with contrasting hydrologic regimes at a lake on Cape Cod, MA. These factors included water...
Authors
Deborah Stoliker, Deborah A. Repert, Richard L. Smith, Bongkeun Song, Denis R. LeBlanc, Timothy McCobb, Christopher Conaway, Sung Pil Hyun, Dong-Chan Koh, Hee Sun Moon, Douglas B. Kent