Research Topics
| J K BöhlkeSummaryAffiliation: U.S. Geological Survey Country: USA Publications
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Detail Information
Publications
Oxygen isotopes in nitrate: new reference materials for 18O:17O:16O measurements and observations on nitrate-water equilibrationJ K Böhlke
US Geological Survey, 431 National Center, Reston, VA 20192, USA
Rapid Commun Mass Spectrom 17:1835-46. 2003..2 per thousand; USGS32 has delta(18)O = +25.7 per thousand; USGS34 has delta(18)O = -27.9 per thousand and delta(17)O = -14.8 per thousand; and USGS35 has delta(18)O = +57.5 per thousand and delta(17)O = +51.5 per thousand...
Contrasting residence times and fluxes of water and sulfate in two small forested watersheds in Virginia, USAJohn Karl Böhlke
U S Geological Survey, 431 National Center, Reston, VA 20192, USA
Sci Total Environ 407:4363-77. 2009....
Atacama perchlorate as an agricultural contaminant in groundwater: isotopic and chronologic evidence from Long Island, New YorkJohn Karl Böhlke
U S Geological Survey, 431 National Center, Reston, Virginia 20192, USA
Environ Sci Technol 43:5619-25. 2009....
Isotopic analysis of N and o in nitrite and nitrate by sequential selective bacterial reduction to N2OJohn Karl Böhlke
U S Geological Survey, 431 National Center, Reston, Virginia 20192, USA
Anal Chem 79:5888-95. 2007..A test of these methods in an agricultural watershed in Indiana provides isotopic evidence for both nitrification and denitrification as sources of NO2- in a small stream...
Ground water stratification and delivery of nitrate to an incised stream under varying flow conditionsJ K Böhlke
USGS, 431 National Center, Reston, VA 20192, USA
J Environ Qual 36:664-80. 2007..Results from this and similar studies illustrate the importance of near-stream geomorphology and subsurface geology as controls of riparian zone function and delivery of nitrate to streams in agricultural watersheds...
Mass balance and isotope effects during nitrogen transport through septic tank systems with packed-bed (sand) filtersStephen R Hinkle
U S Geological Survey, 2130 SW 5th Avenue, Portland, OR 97201, USA
Sci Total Environ 407:324-32. 2008..2 to -2.3 per thousand (mean -6.4 per thousand+/-1.8 per thousand), and were intermediate between a 2/3 H2O-O+1/3 O2-O conceptualization and a 100% H2O-O conceptualization of delta18O-NO3(-) generation during nitrification...
Assessment of nitrification potential in ground water using short term, single-well injection experimentsR L Smith
U S Geological Survey, 3215 Marine St, Boulder, CO, USA
Microb Ecol 51:22-35. 2006..Nonetheless, these tests were useful for characterizing ground water nitrification in situ and for comparing potential rates of activity when the tracer cloud included non-limiting ammonium and oxygen concentrations...
Using dual-bacterial denitrification to improve delta15N determinations of nitrates containing mass-independent 17OT B Coplen
US Geological Survey, 431 National Center, Reston, VA 20192, USA
Rapid Commun Mass Spectrom 18:245-50. 2004..The 1-sigma uncertainties of delta(15)N, delta(18)O and Delta(17)O measurements are +/-0.2, +/-0.3 and +/-5 per thousand, respectively...
Biogeochemistry at a wetland sediment-alluvial aquifer interface in a landfill leachate plumeMichelle M Lorah
U S Geological Survey, 5522 Research Park Drive, Baltimore, MD 21228, USA
J Contam Hydrol 105:99-117. 2009..Slough porewater geochemistry also indicated that the slough could be a source of sulfate in dry conditions, potentially providing a terminal electron acceptor for natural attenuation of organic compounds in the leachate plume...
Regional patterns in the isotopic composition of natural and anthropogenic nitrate in groundwater, High Plains, U.S.AP B McMahon
United States Geological Survey, Lakewood, Colorado 80225, USA
Environ Sci Technol 40:2965-70. 2006..The relative importance of different isotope fractionating processes may be influenced by regional climate patterns as well as by local variation in soils, vegetation, topography, and moisture conditions...
Limited occurrence of denitrification in four shallow aquifers in agricultural areas of the United StatesChristopher T Green
U S Geological Survey, 345 Middlefield Rd, Menlo Park, CA 94025, USA
J Environ Qual 37:994-1009. 2008..In the shallow aquifers below these agricultural fields, denitrification is limited in extent and will require residence times of decades or longer to mitigate modern nitrate contamination...
Effects of nitrate and water on the oxygen isotopic analysis of barium sulfate precipitated from water samplesJanet E Hannon
U S Geological Survey, 431 National Center, 12201 Sunrise Valley Drive, Reston, VA 20192, USA
Rapid Commun Mass Spectrom 22:4109-20. 2008..These results have implications for the calibration and use of O isotope data in studies of SO(4) (2-) sources and reaction mechanisms...
Biogeochemical evolution of a landfill leachate plume, Norman, OklahomaI M Cozzarelli
U S Geological Survey, Reston, VA 20192, USA
Ground Water 49:663-87. 2011..Accurately describing the biogeochemical processes that affect the transport of contaminants in this landfill-leachate-affected aquifer required understanding the aquifer's geologic and hydrodynamic framework...
