John Karl Bohlke, PhD
Dr. John Karl Bohlke is a Scientist Emeritus affiliated with the Earth Systems Processes Division and the Reston Stable Isotope Laboratory of the USGS Water Resources Mission Area.
Dr. John Karl (JK) Bohlke retired as a Senior Research Scientist and currently serves as a Scientist Emeritus affiliated with the Earth System Processes Division and the Reston Stable Isotope Laboratory of the Water Mission Area. During his career with USGS, he has studied processes related to both mineral resources and water resources. His published work includes field and laboratory-based studies of water-rock interactions, geochronology, and chemical transport in diverse hydrogeologic settings. Recent activities include development of stable isotopic methods and applications in hydrology and biogeochemistry, use of isotopes and environmental tracers to determine transport and reaction rates in groundwater and surface water, and multidisciplinary investigations of contaminant origin and migration. Selected priority topics related to water quality include excess nutrients and inorganic contaminants, effects of agriculture and wastewater disposal practices, watershed responses to land use change, groundwater/surface water interactions, and environmental forensics.
Professional Experience
Hydrologist, National Research Program and Earth System Processes Division, Water Mission Area, US Geological Survey, Reston, Virginia (since 1991)
Geologist, Eastern Mineral Resources, US Geological Survey, Reston, Virginia
Postdoc (Geoscience), Argonne National Laboratory, Chicago, Illinois
Geologist, Western Mineral Resources, US Geological Survey, Menlo Park, California
Cartographer, US Soil Conservation Service, Hyattsville, Maryland
Education and Certifications
PhD (Geology and Geophysics), University of California, Berkeley, California
MS (Marine Geology), Rosenstiel School of Marine and Atmospheric Sciences, University of Miami, Florida
BS (Geology), University of Michigan, Ann Arbor, Michigan
Science and Products
Filter Total Items: 200
Strontium isotope geochemistry of groundwaters and streams affected by agriculture, Locust Grove, MD Strontium isotope geochemistry of groundwaters and streams affected by agriculture, Locust Grove, MD
The effects of agriculture on the isotope geochemistry of Sr were investigated in two small watersheds in the Atlantic coastal plain of Maryland. Stratified shallow oxic groundwaters in both watersheds contained a retrievable record of increasing recharge rates of chemicals including NO3−, Cl, Mg, Ca and Sr that were correlated with increasing fertilizer use between about 1940 and 1990...
Authors
J.K. Böhlke, M. Horan
Monthly variability and possible sources of nitrate in ground water beneath mixed agricultural land use, Suwannee and Lafayette Counties, Florida Monthly variability and possible sources of nitrate in ground water beneath mixed agricultural land use, Suwannee and Lafayette Counties, Florida
In an area of mixed agricultural land use in Suwannee and Lafayette Counties of northern Florida, water samples were collected monthly from 14 wells tapping the Upper Floridan aquifer during July 1998 through June 1999 to assess hydrologic and land-use factors affecting the variability in nitrate concentrations in ground water. Unusually high amounts of rainfall in September and October...
Authors
Brian G. Katz, J.K. Böhlke
Chemical and isotopic composition of water from springs, wells, and streams in parts of Shenandoah National Park, Virginia, and vicinity, 1995-1999 Chemical and isotopic composition of water from springs, wells, and streams in parts of Shenandoah National Park, Virginia, and vicinity, 1995-1999
No abstract available.
Authors
Niel Plummer, Eurybiades Busenberg, John Karl Bohlke, R.W. Carmody, G.C. Casile, T. B. Coplen, M. W. Doughten, J.E. Hannon, Wandee Kirkland, R.L. Michel, D.L. Nelms, B.C. Norton, K.E. Plummer, Haiping Qi, Kinga Revesz, Peter Schlosser, Shane Spitzer, J.E. Wayland, P.K. Widman
Use of nitrogen isotopes to determine sources of nitrate contamination in two desert basins in California Use of nitrogen isotopes to determine sources of nitrate contamination in two desert basins in California
Nitrogen-15/14 isotope ratios (δ15N) were measured in groundwater, infiltrating wastewater, and natural uncontaminated soil to determine the source of high NO3- concentrations in two desert basins at Fort Irwin National Training Center in the Mojave Desert. The abundance and isotopic composition of dissolved nitrogen gas were measured in some of the groundwater samples to determine the...
Authors
J.N. Densmore, J.K. Böhlke
Sources and chronology of nitrate contamination in spring waters, Suwannee River basin, Florida Sources and chronology of nitrate contamination in spring waters, Suwannee River basin, Florida
A multi-tracer approach, which consisted of analyzing water samples for n aturally occurring chemical and isotopic indicators, was used to better understand sources and chronology of nitrate contamination in spring wate rs discharging to the Suwannee and Santa Fe Rivers in northern Florida. Dur ing 1997 and 1998, as part of a cooperative study between the Suwannee River Water Management...
Authors
Brian G. Katz, H.D. Hornsby, J. K. Bohlke, M.F. Mokray
U.S. Geological Survey Toxic Substances Hydrology Program: Proceedings of the technical meeting, Charleston, South Carolina, March 8-12, 1999: Volume 3 (Part C) U.S. Geological Survey Toxic Substances Hydrology Program: Proceedings of the technical meeting, Charleston, South Carolina, March 8-12, 1999: Volume 3 (Part C)
This report contains papers presented at the seventh Technical Meeting of the U.S. Geological Survey (USGS), Toxic Substances Hydrology (Toxics) Program. The meeting was held March 8-12, 1999, in Charleston, South Carolina. Toxics Program Technical Meetings are held periodically to provide a forum for presentation and discussion of results of recent research activities.The objectives of...
Sources of nitrate in water from springs and the Upper Floridan aquifer, Suwannee River basin, Florida Sources of nitrate in water from springs and the Upper Floridan aquifer, Suwannee River basin, Florida
In the Suwannee River basin of northern Florida, nitrate-N concentrations are 1.5 to 20 mg 1-1 in waters of the karstic Upper Floridan aquifer and in springs that discharge into the middle reach of the Suwannee River. During 1996-1997, fertilizers and animal wastes from farming operations in Suwannee County contributed approximately 49% and 45% of the total N input, respectively. Values...
Authors
B. G. Katz, H.D. Hornsby, J.K. Böhlke
Denitrification in marine shales in northeastern Colorado Denitrification in marine shales in northeastern Colorado
Parts of the South Platte River alluvial aquifer in northeastern Colorado are underlain by the Pierre Shale, a marine deposit of Late Cretaceous age that is
Authors
Peter B. McMahon, J.K. Böhlke, Breton W. Bruce
δ18O and δ15N determination in nitrate δ18O and δ15N determination in nitrate
No abstract available.
Authors
K. Revesz, J.K. Böhlke, T. Yoshinari
Preliminary estimates of residence times and apparent ages of ground water in the Chesapeake Bay watershed, and water-quality data from a survey of springs Preliminary estimates of residence times and apparent ages of ground water in the Chesapeake Bay watershed, and water-quality data from a survey of springs
Knowledge of the residence times of the ground-water systems in Chesapeake Bay watershed helps resource managers anticipate potential delays between implementation of land-management practices and any improve-ments in river and estuary water quality. This report presents preliminary estimates of ground-water residence times and apparent ages of water in the shallow aquifers of the...
Authors
Michael J. Focazio, Niel Plummer, John K. Bohlke, Eurybiades Busenberg, L. Joseph Bachman, David S. Powars
Non-USGS Publications**
Sturchio, N.C., Böhlke, J.K., and Binz, C.M., 1989, Radium-thorium disequilibrium and zeolite-water ion exchange in a Yellowstone hydrothermal environment. Geochimica et Cosmochimica Acta, v. 53, p. 1025-1034, https://doi.org/10.1016/0016-7037(89)90207-X.
Abrajano, T.A., Bates, J.K., and Böhlke, J.K., 1988, Linear free energy relationships in glass corrosion. Materials Issues in Art and Archeaology, Materials Research Society Proceedings, v. 125, p. 383-392, https://www.osti.gov/biblio/7179346/.
Abrajano, T.A., Sturchio, N.C., Böhlke, J.K., Poreda, R.J., Lyon, G.L., and Stevens, C.M., 1988, Methane-hydrogen gas seeps, Zambales, Philippines: Deep or shallow origin. Chemical Geology, v. 71, p. 211-222, https://doi.org/10.1016/0009-2541(88)90116-7.
Böhlke, 1988, Carbonate-sulfide equilibria and "stratabound" disseminated epigenetic gold mineralization: A proposal based on examples from Alleghany, California. Applied Geochemistry, v. 3, p. 499-516, https://doi.org/10.1016/0883-2927(88)90022-4.
Böhlke, J.K., Alt, J.C., and Muehlenbachs, K., 1984, Oxygen isotope-water relations in altered deep-sea basalts: Low temperature mineralogic controls. Canadian Journal of Earth Sciences, v. 21, p. 67-77, https://doi.org/10.1139/e84-008.
Böhlke, J.K., Honnorez, J., Honnorez-Guerstein, B.M., Muehlenbachs, K., and Petersen, N., 1981, Heterogeneous alteration of the upper oceanic crust: Correlation of rock chemistry, magnetic properties, and O-isotope ratios with alteration patterns in basalts from Site 396B, DSDP. Journal of Geophysical Research, Solid Earth, v. 86, p. 7935-7950, https://doi.org/10.1029/JB086iB09p07935.
Böhlke, J.K., Honnorez, J., and Honnorez-Guerstein, B.-M., 1980, Alteration of basalts from Site 396B, Deep Sea Drilling Project, petrographic and mineralogic studies. Contributions to Mineralogy and Petrology, v. 73, p. 341-364, https://doi.org/10.1007/BF00376628.
**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
Filter Total Items: 200
Strontium isotope geochemistry of groundwaters and streams affected by agriculture, Locust Grove, MD Strontium isotope geochemistry of groundwaters and streams affected by agriculture, Locust Grove, MD
The effects of agriculture on the isotope geochemistry of Sr were investigated in two small watersheds in the Atlantic coastal plain of Maryland. Stratified shallow oxic groundwaters in both watersheds contained a retrievable record of increasing recharge rates of chemicals including NO3−, Cl, Mg, Ca and Sr that were correlated with increasing fertilizer use between about 1940 and 1990...
Authors
J.K. Böhlke, M. Horan
Monthly variability and possible sources of nitrate in ground water beneath mixed agricultural land use, Suwannee and Lafayette Counties, Florida Monthly variability and possible sources of nitrate in ground water beneath mixed agricultural land use, Suwannee and Lafayette Counties, Florida
In an area of mixed agricultural land use in Suwannee and Lafayette Counties of northern Florida, water samples were collected monthly from 14 wells tapping the Upper Floridan aquifer during July 1998 through June 1999 to assess hydrologic and land-use factors affecting the variability in nitrate concentrations in ground water. Unusually high amounts of rainfall in September and October...
Authors
Brian G. Katz, J.K. Böhlke
Chemical and isotopic composition of water from springs, wells, and streams in parts of Shenandoah National Park, Virginia, and vicinity, 1995-1999 Chemical and isotopic composition of water from springs, wells, and streams in parts of Shenandoah National Park, Virginia, and vicinity, 1995-1999
No abstract available.
Authors
Niel Plummer, Eurybiades Busenberg, John Karl Bohlke, R.W. Carmody, G.C. Casile, T. B. Coplen, M. W. Doughten, J.E. Hannon, Wandee Kirkland, R.L. Michel, D.L. Nelms, B.C. Norton, K.E. Plummer, Haiping Qi, Kinga Revesz, Peter Schlosser, Shane Spitzer, J.E. Wayland, P.K. Widman
Use of nitrogen isotopes to determine sources of nitrate contamination in two desert basins in California Use of nitrogen isotopes to determine sources of nitrate contamination in two desert basins in California
Nitrogen-15/14 isotope ratios (δ15N) were measured in groundwater, infiltrating wastewater, and natural uncontaminated soil to determine the source of high NO3- concentrations in two desert basins at Fort Irwin National Training Center in the Mojave Desert. The abundance and isotopic composition of dissolved nitrogen gas were measured in some of the groundwater samples to determine the...
Authors
J.N. Densmore, J.K. Böhlke
Sources and chronology of nitrate contamination in spring waters, Suwannee River basin, Florida Sources and chronology of nitrate contamination in spring waters, Suwannee River basin, Florida
A multi-tracer approach, which consisted of analyzing water samples for n aturally occurring chemical and isotopic indicators, was used to better understand sources and chronology of nitrate contamination in spring wate rs discharging to the Suwannee and Santa Fe Rivers in northern Florida. Dur ing 1997 and 1998, as part of a cooperative study between the Suwannee River Water Management...
Authors
Brian G. Katz, H.D. Hornsby, J. K. Bohlke, M.F. Mokray
U.S. Geological Survey Toxic Substances Hydrology Program: Proceedings of the technical meeting, Charleston, South Carolina, March 8-12, 1999: Volume 3 (Part C) U.S. Geological Survey Toxic Substances Hydrology Program: Proceedings of the technical meeting, Charleston, South Carolina, March 8-12, 1999: Volume 3 (Part C)
This report contains papers presented at the seventh Technical Meeting of the U.S. Geological Survey (USGS), Toxic Substances Hydrology (Toxics) Program. The meeting was held March 8-12, 1999, in Charleston, South Carolina. Toxics Program Technical Meetings are held periodically to provide a forum for presentation and discussion of results of recent research activities.The objectives of...
Sources of nitrate in water from springs and the Upper Floridan aquifer, Suwannee River basin, Florida Sources of nitrate in water from springs and the Upper Floridan aquifer, Suwannee River basin, Florida
In the Suwannee River basin of northern Florida, nitrate-N concentrations are 1.5 to 20 mg 1-1 in waters of the karstic Upper Floridan aquifer and in springs that discharge into the middle reach of the Suwannee River. During 1996-1997, fertilizers and animal wastes from farming operations in Suwannee County contributed approximately 49% and 45% of the total N input, respectively. Values...
Authors
B. G. Katz, H.D. Hornsby, J.K. Böhlke
Denitrification in marine shales in northeastern Colorado Denitrification in marine shales in northeastern Colorado
Parts of the South Platte River alluvial aquifer in northeastern Colorado are underlain by the Pierre Shale, a marine deposit of Late Cretaceous age that is
Authors
Peter B. McMahon, J.K. Böhlke, Breton W. Bruce
δ18O and δ15N determination in nitrate δ18O and δ15N determination in nitrate
No abstract available.
Authors
K. Revesz, J.K. Böhlke, T. Yoshinari
Preliminary estimates of residence times and apparent ages of ground water in the Chesapeake Bay watershed, and water-quality data from a survey of springs Preliminary estimates of residence times and apparent ages of ground water in the Chesapeake Bay watershed, and water-quality data from a survey of springs
Knowledge of the residence times of the ground-water systems in Chesapeake Bay watershed helps resource managers anticipate potential delays between implementation of land-management practices and any improve-ments in river and estuary water quality. This report presents preliminary estimates of ground-water residence times and apparent ages of water in the shallow aquifers of the...
Authors
Michael J. Focazio, Niel Plummer, John K. Bohlke, Eurybiades Busenberg, L. Joseph Bachman, David S. Powars
Non-USGS Publications**
Sturchio, N.C., Böhlke, J.K., and Binz, C.M., 1989, Radium-thorium disequilibrium and zeolite-water ion exchange in a Yellowstone hydrothermal environment. Geochimica et Cosmochimica Acta, v. 53, p. 1025-1034, https://doi.org/10.1016/0016-7037(89)90207-X.
Abrajano, T.A., Bates, J.K., and Böhlke, J.K., 1988, Linear free energy relationships in glass corrosion. Materials Issues in Art and Archeaology, Materials Research Society Proceedings, v. 125, p. 383-392, https://www.osti.gov/biblio/7179346/.
Abrajano, T.A., Sturchio, N.C., Böhlke, J.K., Poreda, R.J., Lyon, G.L., and Stevens, C.M., 1988, Methane-hydrogen gas seeps, Zambales, Philippines: Deep or shallow origin. Chemical Geology, v. 71, p. 211-222, https://doi.org/10.1016/0009-2541(88)90116-7.
Böhlke, 1988, Carbonate-sulfide equilibria and "stratabound" disseminated epigenetic gold mineralization: A proposal based on examples from Alleghany, California. Applied Geochemistry, v. 3, p. 499-516, https://doi.org/10.1016/0883-2927(88)90022-4.
Böhlke, J.K., Alt, J.C., and Muehlenbachs, K., 1984, Oxygen isotope-water relations in altered deep-sea basalts: Low temperature mineralogic controls. Canadian Journal of Earth Sciences, v. 21, p. 67-77, https://doi.org/10.1139/e84-008.
Böhlke, J.K., Honnorez, J., Honnorez-Guerstein, B.M., Muehlenbachs, K., and Petersen, N., 1981, Heterogeneous alteration of the upper oceanic crust: Correlation of rock chemistry, magnetic properties, and O-isotope ratios with alteration patterns in basalts from Site 396B, DSDP. Journal of Geophysical Research, Solid Earth, v. 86, p. 7935-7950, https://doi.org/10.1029/JB086iB09p07935.
Böhlke, J.K., Honnorez, J., and Honnorez-Guerstein, B.-M., 1980, Alteration of basalts from Site 396B, Deep Sea Drilling Project, petrographic and mineralogic studies. Contributions to Mineralogy and Petrology, v. 73, p. 341-364, https://doi.org/10.1007/BF00376628.
**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.