John Karl Bohlke
Dr. John Karl Bohlke is a Scientist Emeritus with the USGS Water Resources Mission Area and the Reston Stable Isotope Laboratory.
Professional Experience
Hydrologist, National Research Program and Earth System Processes Division, Water Mission Area, US Geological Survey, Reston, Virginia (since 1991)
[Adjunct Assist/Assoc Professor (Geology), University of Maryland (1992-2016)]
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
Groundwater record of halocarbon transport by the Danube River
Determination of δ18O and δ15N in Nitrate
Tritium/3He dating of river infiltration: an example from the Danube in the Szigetkoz Area, Hungary
Chemical and stable-isotope data from an experiment to examine temporal variability in water samples from screened wells on Cape Cod, Massachusetts, 1994
Denitrification and mixing in a stream-aquifer system: Effects on nitrate loading to surface water
Groundwater origin and dating studies in Szigetkoz
Isotope hydrology studies in the Szigetköz region, northwest Hungary
Combined use of groundwater dating, chemical, and isotopic analyses to resolve the history and fate of nitrate contamination in two agricultural watersheds, Atlantic coastal plain, Maryland
Interlaboratory comparison of reference materials for nitrogen-isotope-ratio measurements
Stable isotopes in mid-ocean ridge hydrothermal systems: Interactions between fluids, minerals, and organisms
Effect of ground-water/surface-water interactions on nitrate concentrations in discharge from the South Platte River alluvial aquifer, Colorado
Chemical analyses of ground and surface water from Battle Brook drainage basin, near Princeton, Minnesota
Science and Products
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Filter Total Items: 194
Groundwater record of halocarbon transport by the Danube River
Groundwater dating studies have supported the concept that aquifers with low coefficients of dispersion may contain coherent records of past conditions in recharge areas. Groundwater records can provide unique information about natural or anthropogenic changes in the atmosphere and hydrosphere where long-term monitoring data are not available. Here we describe a 40-year record of halocarbon contamAuthorsJ.K. Böhlke, K. Revesz, E. Busenberg, J. Deak, E. Deseo, M. StuteDetermination of δ18O and δ15N in Nitrate
The analyses of both O and N isotopic compositions of nitrate have many potential applications in studies of nitrate sources and reactions in hydrology, oceanography, and atmospheric chemistry, but simple and precise methods for these analyses have yet to be developed. Testing of a new method involving reaction of potassium nitrate with catalyzed graphite (C + Pd + Au) at 520 °C resulted in quantiAuthorsK. Revesz, J.K. Böhlke, T. YoshinariTritium/3He dating of river infiltration: an example from the Danube in the Szigetkoz Area, Hungary
3H, 3He, 4He, and Ne data were obtained from a shallow ground-water system being recharged by bank infiltration from the Danube River in northwestern Hungary. After correting for excess air, 4He and Ne concentrations reflect a recharge temperature of about 9?? C, close to the mean annual temperature of the Danube (10.4?? C). Values of 3H plus 3Hetrit, ("initial tritium") as a function of the tritiChemical and stable-isotope data from an experiment to examine temporal variability in water samples from screened wells on Cape Cod, Massachusetts, 1994
No abstract available.AuthorsT. E. Reilly, D.R. LeBlanc, K.W. Bussey, T.B. Councell, R. L. Smith, J.K. BöhlkeDenitrification and mixing in a stream-aquifer system: Effects on nitrate loading to surface water
Ground water in terrace deposits of the South Platte River alluvial aquifer near Greeley, Colorado, USA, had a median nitrate concentration of 1857 μmol l−1. Median nitrate concentrations in ground water from adjacent floodplain deposits (468 μmol l−1) and riverbed sediments (461 μmol l−1), both of which are downgradient from the terrace deposits, were lower than the median concentration in the teAuthorsP. B. McMahon, J.K. BöhlkeGroundwater origin and dating studies in Szigetkoz
No abstract available.AuthorsE. Deseo, J. Deak, K. Revesz, John K. Böhlke, M. StuteIsotope hydrology studies in the Szigetköz region, northwest Hungary
No abstract available.AuthorsJ. Deak, E. Deseo, John K. Böhlke, K. ReveszCombined use of groundwater dating, chemical, and isotopic analyses to resolve the history and fate of nitrate contamination in two agricultural watersheds, Atlantic coastal plain, Maryland
The history and fate of groundwater nitrate (NO3−) contamination were compared in 2 small adjacent agricultural watersheds in the Atlantic coastal plain by combined use of chronologic (CCl2F2, 3H), chemical (dissolved solids, gases), and isotopic (δ15N,δ13C, δ34S) analyses of recharging groundwaters, discharging groundwaters, and surface waters. The results demonstrate the interactive effects of cAuthorsJ.K. Böhlke, J. M. DenverInterlaboratory comparison of reference materials for nitrogen-isotope-ratio measurements
Aliquots of seven different reference materials were distributed for an interlaboratory comparison of stable nitrogen-isotope-ratio measurements. Results from 15 laboratories were compiled and evaluated selectively to yield provisional values of 515N for each material, i, with respect to atmospheric N2 (o1SN,7air). The 515N values reported by the different laboratories are correlated in such a wayAuthorsJohn K. Böhlke, Tyler B. CoplenStable isotopes in mid-ocean ridge hydrothermal systems: Interactions between fluids, minerals, and organisms
Studies of abundance variations of light stable isotopes in nature have had a tremendous impact on all aspects of geochemistry since the development, in 1947, of a gas source isotope ratio mass spectrometer capable of measuring small variations in stable isotope ratios (Nice, 1947]. Stable isotope geochemistry is now a mature field, as witnessed by the proliferation of commercially available massAuthorsWayne C. Shanks, John K. Böhlke, Robert R. SealEffect of ground-water/surface-water interactions on nitrate concentrations in discharge from the South Platte River alluvial aquifer, Colorado
Concentrations of dissolved nitrate in recharge-area water from a 200-km2 segment of the South Platte River alluvial aquifer near Greeley, Colorado, range from less than 0.1 to 58 mg/l as nitrogen, and the median concentration is 26 mg/l as nitrogen. Hydraulic-head data indicate that this nitrate-enriched ground water move toward the South Platte River. However, the median concentration of nitrateAuthorsP. B. McMahon, J.K. BöhlkeChemical analyses of ground and surface water from Battle Brook drainage basin, near Princeton, Minnesota
No abstract available.AuthorsR. B. Wanty, M. L. Tuttle, J.K. Böhlke, Paul H. Briggs