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
The influence of sample matrix on the accuracy of nitrite N and O isotope ratio analyses with the azide method
Assessing the seasonal dynamics of nitrate and sulfate aerosols at the South Pole utilizing stable isotopes
Seasonal and spatial variation in the location and reactivity of a nitrate-contaminated groundwater discharge zone in a lakebed
Methane and nitrous oxide temporal and spatial variability in two midwestern USA streams containing high nitrate concentrations
Constraining the oxygen isotopic composition of nitrate produced by nitrification
IUPAC Periodic Table of the Elements and Isotopes (IPTEI) for the education community (IUPAC Technical Report)
Seasonality of nitrate sources and isotopic composition in the Upper Illinois River
Four-dimensional isotopic approach to identify perchlorate sources in groundwater: Application to the Rialto-Colton and Chino subbasins, southern California (USA)
Geochemical conditions and nitrogen transport in nearshore groundwater and the subterranean estuary at a Cape Cod embayment, East Falmouth, Massachusetts, 2013–14
Tracing the cycling and fate of the munition, Hexahydro-1,3,5-trinitro-1,3,5-triazine in a simulated sandy coastal marine habitat with a stable isotopic tracer, 15N-[RDX]
Minimum energy requirements for desalination of brackish groundwater in the United States with comparison to international datasets
Validation of stable isotope ratio analysis to document the biodegradation and natural attenuation of RDX, ESTCP Project ER-201208
Science and Products
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Filter Total Items: 193
The influence of sample matrix on the accuracy of nitrite N and O isotope ratio analyses with the azide method
RationaleThe isotope ratios of nitrogen (15N/14N) and oxygen (18O/16O) in nitrite (NO2−) can be measured by conversion of the nitrite into nitrous oxide (N2O) with azide, followed by mass spectrometric analysis of N2O by gas chromatography isotope ratio mass spectrometry (GC/IRMS). While applying this method to brackish samples, we noticed that the N and O isotope ratio measurements of NO2− are hiAuthorsJulie Granger, Danielle S. Boshers, John K. Böhlke, Dan Yu, Nengwang Chen, Craig R. TobiasAssessing the seasonal dynamics of nitrate and sulfate aerosols at the South Pole utilizing stable isotopes
Atmospheric nitrate (NO3− = particulate NO3− + gas‐phase nitric acid [HNO3]) and sulfate (SO42−) are key molecules that play important roles in numerous atmospheric processes. Here, the seasonal cycles of NO3− and total suspended particulate sulfate (SO42−(TSP)) were evaluated at the South Pole from aerosol samples collected weekly for approximately 10 months (26 January to 25 October) in 2002 andAuthorsW.W. Walters, G. Michalski, John K. Böhlke, B. Alexander, J. Savarino, M.H. ThiemensSeasonal 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, grounAuthorsRichard L. Smith, Deborah A. Repert, Deborah Stoliker, Douglas B. Kent, Bongkeun Song, Denis R. LeBlanc, Timothy McCobb, John K. Böhlke, Sung Pil Hyun, Hee Sun MoonMethane and nitrous oxide temporal and spatial variability in two midwestern USA streams containing high nitrate concentrations
Concentrations and emissions of greenhouse gases CO2, CH4, and N2O commonly are examined individually in aquatic environments in which each is expected to be relatively important; however, their co-occurrence and dynamic interactions in fluvial settings could provide important information about their controlling biogeochemical processes and potential contributions to global climate change. SpatialAuthorsRichard L. Smith, John K. BöhlkeConstraining the oxygen isotopic composition of nitrate produced by nitrification
Measurements of the stable isotope ratios of nitrogen (15N/14N) and oxygen (18O/16O) in nitrate (NO3–) enable identification of sources, dispersal, and fate of natural and contaminant NO3– in aquatic environments. The 18O/16O of NO3– produced by nitrification is often assumed to reflect the proportional contribution of oxygen atom sources, water, and molecular oxygen, in a 2:1 ratio. Culture and sAuthorsDanielle S. Boshers, Julie Granger, Craig R. Tobias, John K. Böhlke, Richard L. SmithIUPAC Periodic Table of the Elements and Isotopes (IPTEI) for the education community (IUPAC Technical Report)
The IUPAC (International Union of Pure and Applied Chemistry) Periodic Table of the Elements and Isotopes (IPTEI) was created to familiarize students, teachers, and non-professionals with the existence and importance of isotopes of the chemical elements. The IPTEI is modeled on the familiar Periodic Table of the Chemical Elements. The IPTEI is intended to hang on the walls of chemistry laboratorieAuthorsNorman E. Holden, Tyler B. Coplen, John K. Böhlke, Lauren V. Tarbox, Jacqueline Benefield, John R. de Laeter, Peter G. Mahaffy, Glenda O’Connor née Singleton, Etienne Roth, Dorothy Tepper, Thomas Walczyk, Michael E. Wieser, Shigekazu YonedaSeasonality of nitrate sources and isotopic composition in the Upper Illinois River
To improve understanding of spatial, seasonal, and inter-annual variations in nitrate sources and in-stream processes in the Illinois River system, nitrate concentrations and isotopic compositions were measured in 445 water samples collected over a four-year period (2004–2008) from the Upper Illinois River Basin (UIRB). Samples included surface water in the river and major tributaries, effluent saAuthorsJiajia Lin, John K. Böhlke, Sheng Huang, Miquel Gonzalez-Meler, Neil C. SturchioFour-dimensional isotopic approach to identify perchlorate sources in groundwater: Application to the Rialto-Colton and Chino subbasins, southern California (USA)
Perchlorate (ClO4−) in groundwater can be from synthetic or natural sources. Natural sources include ClO4− associated with historical application of imported natural nitrate fertilizer from the Atacama Desert of Chile, and indigenous ClO4− that accumulates locally in arid regions from atmospheric deposition. The Rialto-Colton groundwater subbasin, 80 km east of Los Angeles, California, includes twAuthorsPaul B. Hatzinger, John K. Böhlke, Neil C. Sturchio, John A. Izbicki, Nicholas F. TeagueGeochemical conditions and nitrogen transport in nearshore groundwater and the subterranean estuary at a Cape Cod embayment, East Falmouth, Massachusetts, 2013–14
Nitrogen transport and transformation were studied during 2013 to 2014 by the U.S. Geological Survey, in cooperation with the U.S. Environmental Protection Agency, in a subterranean estuary beneath onshore locations on the Seacoast Shores peninsula, a residential area in Falmouth, Massachusetts, served by septic systems and cesspools, and adjacent offshore locations in the Eel River, a saltwater eAuthorsJohn A. Colman, Denis R. LeBlanc, John K. Böhlke, Timothy D. McCobb, Kevin D. Kroeger, Marcel Belaval, Thomas C. Cambareri, Gillian F. Pirolli, T. Wallace Brooks, Mary E. Garren, Tobias B. Stover, Ann KeeleyTracing the cycling and fate of the munition, Hexahydro-1,3,5-trinitro-1,3,5-triazine in a simulated sandy coastal marine habitat with a stable isotopic tracer, 15N-[RDX]
Coastal marine habitats become contaminated with the munitions constituent, Hexahydro-1,3,5-trinitro-1,3,5-trazine (RDX), via military training, weapon testing and leakage of unexploded ordnance. This study used 15N labeled RDX in simulated aquarium-scale coastal marine habitat containing seawater, sediment, and biota to track removal pathways from surface water including sorption onto particulateAuthorsThivanka Ariyarathna, Mark Ballentine, Penny Vlahos, Richard W. Smith, Christopher Cooper, John K. Böhlke, Stephen Fallis, Thomas J. Groshens, Craig R. TobiasMinimum energy requirements for desalination of brackish groundwater in the United States with comparison to international datasets
This paper uses chemical and physical data from a large 2017 U.S. Geological Surveygroundwater dataset with wells in the U.S. and three smaller international groundwater datasets with wells primarily in Australia and Spain to carry out a comprehensive investigation of brackish groundwater composition in relation to minimum desalinationenergy costs. First, we compute the site-specific least work reAuthorsYvana D. Ahdab, Gregory P. Thiel, John K. Böhlke, Jennifer S. Stanton, John H. LienhardValidation of stable isotope ratio analysis to document the biodegradation and natural attenuation of RDX, ESTCP Project ER-201208
Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) is a common soil contaminant at current and former military facilities, including many training and testing ranges. Because RDX is readily transported through soils to the subsurface, this nitramine explosive now also impacts groundwater and drinking water at numerous locations across the country. A significant issue with RDX contamination on ranges anAuthorsPaul B. Hatzinger, Mark E. Fuller, Neil C. Sturchio, John K. Böhlke