Chlorine-36 as a tracer of perchlorate origin
N.C. Sturchio, M. Caffee, Abelardo D. Beloso Jr., L.J. Heraty, J.K. Böhlke, P.B. Hatzinger, W.A. Jackson, B. Gu, J.M. Heikoop, M. Dale
2009, Environmental Science & Technology (43) 6934-6938
Perchlorate (ClO4−) is ubiquitous in the environment. It is produced naturally by atmospheric photochemical reactions, and also is synthesized in large quantities for military, aerospace, and industrial applications. Nitrate-enriched salt deposits of the Atacama Desert (Chile) contain high concentrations of natural ClO4−, and have been exported worldwide...
Copper isotope fractionation in acid mine drainage
B.E. Kimball, R. Mathur, A.C. Dohnalkova, A.J. Wall, R.L. Runkel, S.L. Brantley
2009, Geochimica et Cosmochimica Acta (73) 1247-1263
We measured the Cu isotopic composition of primary minerals and stream water affected by acid mine drainage in a mineralized watershed (Colorado, USA). The δ65Cu values (based on 65Cu/63Cu) of enargite (δ65Cu = −0.01 ± 0.10‰; 2σ) and chalcopyrite (δ65Cu = 0.16 ± 0.10‰) are within the range of reported values for terrestrial primary Cu sulfides (−1‰ < δ65Cu < 1‰). These mineral...
Assessing the impact of land use change on hydrology by ensemble modeling (LUCHEM). I: Model intercomparison with current land use
L. Breuer, J. A. Huisman, P. Willems, H. Bormann, A. Bronstert, B.F.W. Croke, H.-G. Frede, T. Graff, L. Hubrechts, A.J. Jakeman, G. Kite, J. Lanini, G. Leavesley, D.P. Lettenmaier, G. Lindstrom, J. Seibert, M. Sivapalan, N.R. Viney
2009, Advances in Water Resources (32) 129-146
This paper introduces the project on 'Assessing the impact of land use change on hydrology by ensemble modeling (LUCHEM)' that aims at investigating the envelope of predictions on changes in hydrological fluxes due to land use change. As part of a series of four papers, this paper outlines the motivation...
Water uptake and nutrient concentrations under a floodplain oak savanna during a non-flood period, lower Cedar River, Iowa
K. E. Schilling, P. Jacobson
2009, Hydrological Processes (23) 3006-3016
Floodplains during non-flood periods are less well documented than when flooding occurs, but non-flood periods offer opportunities to investigate vegetation controls on water and nutrient cycling. In this study, we characterized water uptake and nutrient concentration patterns from 2005 to 2007 under an oak savanna located on the floodplain of...
Rapid changes in small fish mercury concentrations in estuarine wetlands: Implications for wildlife risk and monitoring programs
Collin A. Eagles-Smith, Joshua T. Ackerman
2009, Environmental Science & Technology (43) 8658-8664
Small fish are commonly used to assess mercury (Hg) risk to wildlife and monitor Hg in wetlands. However, limited research has evaluated short-term Hg variability in small fish, which can have important implications for monitoring programs and risk assessment. We conducted a time-series study of Hg concentrations in two small...
Introduction to special section on impacts of land use change on water resources
David A. Stonestrom, Bridget R. Scanlon, Lu Zhang
2009, Water Resources Research (45)
Changes in land use have potentially large impacts on water resources, yet quantifying these impacts remains among the more challenging problems in hydrology. Water, food, energy, and climate are linked through complex webs of direct and indirect effects and feedbacks. Land use is undergoing major changes due not only to...
Fluvial fluxes of water, suspended particulate matter, and nutrients and potential impacts on tropical coastal water Biogeochemistry: Oahu, Hawai'i
D.J. Hoover, F.T. MacKenzie
2009, Aquatic Geochemistry (15) 547-570
Baseflow and storm runoff fluxes of water, suspended particulate matter (SPM), and nutrients (N and P) were assessed in conservation, urban, and agricultural streams discharging to coastal waters around the tropical island of Oahu, Hawai'i. Despite unusually low storm frequency and intensity during the study, storms accounted for 8-77% (median...
Is there evidence of adaptation to tidal flooding in saplings of baldcypress subjected to different salinity regimes?
K. W. Krauss, T.W. Doyle, R.J. Howard
2009, Environmental and Experimental Botany (67) 118-126
Plant populations may adapt to environmental conditions over time by developing genetically based morphological or physiological characteristics. For tidal freshwater forested wetlands, we hypothesized that the conditions under which trees developed led to ecotypic difference in response of progeny to hydroperiod. Specifically, we looked for evidence of ecotypic adaptation for...
Linking hydraulic properties of fire-affected soils to infiltration and water repellency
J. A. Moody, D.A. Kinner, X. Ubeda
2009, Journal of Hydrology (379) 291-303
Heat from wildfires can produce a two-layer system composed of extremely dry soil covered by a layer of ash, which when subjected to rainfall, may produce extreme floods. To understand the soil physics controlling runoff for these initial conditions, we used a small, portable disk infiltrometer to measure two hydraulic...
UZIG USGS research: Advances through interdisciplinary interaction
J. R. Nimmo, Brian J. Andraski, M.-C. Rafael
2009, Vadose Zone Journal (8) 411-413
BBecause vadose zone research relates to diverse disciplines, applications, and modes of research, collaboration across traditional operational and topical divisions is especially likely to yield major advances in understanding. The Unsaturated Zone Interest Group (UZIG) is an informal organization sponsored by the USGS to encourage and support interdisciplinary collaboration in...
Respiratory arsenate reductase as a bidirectional enzyme
C. Richey, P. Chovanec, S.E. Hoeft, R.S. Oremland, P. Basu, J.F. Stolz
2009, Biochemical and Biophysical Research Communications (382) 298-302
The haloalkaliphilic bacterium Alkalilimnicola ehrlichii is capable of anaerobic chemolithoautotrophic growth by coupling the oxidation of arsenite (As(III)) to the reduction of nitrate and carbon dioxide. Analysis of its complete genome indicates that it lacks a conventional arsenite oxidase (Aox), but instead possesses two operons that each encode a putative...
Predicting the biological condition of streams: Use of geospatial indicators of natural and anthropogenic characteristics of watersheds
D.M. Carlisle, J. Falcone, M. R. Meador
2009, Environmental Monitoring and Assessment (151) 143-160
We developed and evaluated empirical models to predict biological condition of wadeable streams in a large portion of the eastern USA, with the ultimate goal of prediction for unsampled basins. Previous work had classified (i.e., altered vs. unaltered) the biological condition of 920 streams based on a biological assessment of...
Age-distribution estimation for karst groundwater: Issues of parameterization and complexity in inverse modeling by convolution
Andrew J. Long, L.D. Putnam
2009, Journal of Hydrology (376) 579-588
Convolution modeling is useful for investigating the temporal distribution of groundwater age based on environmental tracers. The framework of a quasi-transient convolution model that is applicable to two-domain flow in karst aquifers is presented. The model was designed to provide an acceptable level of statistical confidence in parameter estimates when...
Enantiomer fractions of chlordane components in sediment from U.S. Geological Survey sites in lakes and rivers
E.M. Ulrich, W.T. Foreman, P. C. Van Metre, J.T. Wilson, S.A. Rounds
2009, Science of the Total Environment (407) 5884-5893
Spatial, temporal, and sediment-type trends in enantiomer signatures were evaluated for cis- and trans-chlordane (CC, TC) in archived core, suspended, and surficial-sediment samples from six lake, reservoir, and river sites across the United States. The enantiomer fractions (EFs) measured in these samples are in good agreement with those reported for sediment, soil,...
Comparing approaches for simulating the reactive transport of U(VI) in ground water
G.P. Curtis, M. Kohler, J.A. Davis
2009, Mine Water and the Environment (28) 84-93
The reactive transport of U(VI) in a well-characterized shallow alluvial aquifer at a former U(VI) mill located near Naturita, CO, was predicted for comparative purposes using a surface complexation model (SCM) and a constant K d approach to simulate U(VI) adsorption. The ground water at the site had U(VI) concentrations that...
Effects of sediment transport and seepage direction on hydraulic properties at the sediment-water interface of hyporheic settings
D.O. Rosenberry, J. Pitlick
2009, Journal of Hydrology (373) 377-391
Relations between seepage flux and hydraulic properties are difficult to quantify in fluvial settings because of the difficulty in measuring these variables in situ. Tests conducted in a 1.5-m diameter by 1.5-m tall sediment-filled tank indicate that hydraulic gradient increased and hydraulic conductivity (K) decreased following the onset of downward...
First-order exchange coefficient coupling for simulating surface water-groundwater interactions: Parameter sensitivity and consistency with a physics-based approach
B.A. Ebel, B.B. Mirus, C.S. Heppner, J.E. VanderKwaak, K. Loague
2009, Hydrological Processes (23) 1949-1959
Distributed hydrologic models capable of simulating fully-coupled surface water and groundwater flow are increasingly used to examine problems in the hydrologic sciences. Several techniques are currently available to couple the surface and subsurface; the two most frequently employed approaches are first-order exchange coefficients (a.k.a., the surface conductance method) and enforced...
Distinguishing iron-reducing from sulfate-reducing conditions
F. H. Chapelle, P. M. Bradley, M.A. Thomas, P.B. McMahon
2009, Ground Water (47) 300-305
Ground water systems dominated by iron‐ or sulfate‐reducing conditions may be distinguished by observing concentrations of dissolved iron (Fe2+) and sulfide (sum of H2S, HS−, and S= species and denoted here as “H2S”). This approach is based on the observation that concentrations of Fe2+ and H2S in ground water systems tend to...
Biological soil crusts exhibit a dynamic response to seasonal rain and release from grazing with implications for soil stability
Aguilar A. Jimenez, E. Huber-Sannwald, J. Belnap, D.R. Smart, Moreno J.T. Arredondo
2009, Journal of Arid Environments (73) 1158-1169
In Northern Mexico, long-term grazing has substantially degraded semiarid landscapes. In semiarid systems, ecological and hydrological processes are strongly coupled by patchy plant distribution and biological soil crust (BSC) cover in plant-free interspaces. In this study, we asked: 1) how responsive are BSC cover/composition to a drying/wetting cycle and two-year...
Isoscapes to address large-scale earth science challenges
G.J. Bowen, J. B. West, B. H. Vaughn, T. E. Dawson, J.R. Ehleringer, M. L. Fogel, K. Hobson, J. Hoogewerff, C. Kendall, C.-T. Lai, C.C. Miller, D. Noone, H. Schwarcz, C.J. Still
2009, Eos, Transactions, American Geophysical Union (90) 109-110
No abstract available....
Assigning land use to supply wells for the statistical characterization of regional groundwater quality: Correlating urban land use and VOC occurrence
T.D. Johnson, K. Belitz
2009, Journal of Hydrology (370) 100-108
Many national and regional groundwater studies have correlated land use "near" a well, often using a 500 m radius circle, with water quality. However, the use of a 500 m circle may seem counterintuitive given that contributing areas are expected to extend up-gradient from wells, and not be circular in...
Numerical models of caldera deformation: Effects of multiphase and multicomponent hydrothermal fluid flow
M. Hutnak, S. Hurwitz, S. E. Ingebritsen, P. A. Hsieh
2009, Journal of Geophysical Research B: Solid Earth (114)
Ground surface displacement (GSD) in large calderas is often interpreted as resulting from magma intrusion at depth. Recent advances in geodetic measurements of GSD, notably interferometric synthetic aperture radar, reveal complex and multifaceted deformation patterns that often require complex source models to explain the observed GSD. Although hydrothermal fluids have...
Combining particle-tracking and geochemical data to assess public supply well vulnerability to arsenic and uranium
S.R. Hinkle, L. J. Kauffman, M.A. Thomas, C. J. Brown, K. A. McCarthy, S. M. Eberts, Michael R. Rosen, B. G. Katz
2009, Journal of Hydrology (376) 132-142
Flow-model particle-tracking results and geochemical data from seven study areas across the United States were analyzed using three statistical methods to test the hypothesis that these variables can successfully be used to assess public supply well vulnerability to arsenic and uranium. Principal components analysis indicated that arsenic and uranium concentrations...
Effects of introduced fish on macroinvertebrate communities in historically fishless headwater and kettle lakes
Emily Gaenzle Schilling, Cynthia S. Loftin, Alexander D. Huryn
2009, Biological Conservation (142) 3030-3038
Widespread fish introductions have led to a worldwide decline in the number of fishless lakes and their associated communities. Studies assessing effects of fish stocking on native communities in historically fishless lakes have been limited to high-elevation headwater lakes stocked with non-native trout. Little is known about the effect of...
Elevated naturally occurring arsenic in a semiarid oxidizing system, Southern High Plains aquifer, Texas, USA
Bridget R. Scanlon, J.-P. Nicot, R.C. Reedy, D. Kurtzman, A. Mukherjee, D. Kirk Nordstrom
2009, Applied Geochemistry (24) 2061-2071
High groundwater As concentrations in oxidizing systems are generally associated with As adsorption onto hydrous metal (Al, Fe or Mn) oxides and mobilization with increased pH. The objective of this study was to evaluate the distribution, sources and mobilization mechanisms of As in the Southern High Plains (SHP) aquifer, Texas,...
