Effect of hydrological conditions on nitrous oxide, methane, and carbon dioxide dynamics in a bottomland hardwood forest and its implication for soil carbon sequestration
K. Yu, S.P. Faulkner, M.J. Baldwin
2008, Global Change Biology (14) 798-812
This study was conducted at three locations in a bottomland hardwood forest with a distinct elevation and hydrological gradient: ridge (high, dry), transition, and swamp (low, wet). At each location, concentrations of soil greenhouse gases (N2O, CH4, and CO2), their fluxes to the atmosphere, and soil redox potential (Eh) were...
Evaluation of statistical treatments of left-censored environmental data using coincident uncensored data sets: I. Summary statistics
Ronald C. Antweiler, Howard E. Taylor
2008, Environmental Science & Technology (42) 3732-3738
The main classes of statistical treatment of below-detection limit (left-censored) environmental data for the determination of basic statistics that have been used in the literature are substitution methods, maximum likelihood, regression on order statistics (ROS), and nonparametric techniques. These treatments, along with using all instrument-generated data (even those below detection),...
Anthropogenic influences on the input and biogeochemical cycling of nutrients and mercury in Great Salt Lake, Utah, USA
D. Naftz, C. Angeroth, T. Kenney, B. Waddell, N. Darnall, S. Silva, C. Perschon, J. Whitehead
2008, Applied Geochemistry (23) 1731-1744
Despite the ecological and economic importance of Great Salt Lake (GSL), little is known about the input and biogeochemical cycling of nutrients and trace elements in the lake. In response to increasing public concern regarding anthropogenic inputs to the GSL ecosystem, the US Geological Survey (USGS) and US Fish and...
Redox processes and water quality of selected principal aquifer systems
P.B. McMahon, F. H. Chapelle
2008, Ground Water (46) 259-271
Reduction/oxidation (redox) conditions in 15 principal aquifer (PA) systems of the United States, and their impact on several water quality issues, were assessed from a large data base collected by the National Water-Quality Assessment Program of the USGS. The logic of these assessments was based on the observed ecological succession...
Impairment of the reproductive potential of male fathead minnows by environmentally relevant exposures to 4-nonylphenolf
H.L. Schoenfuss, S.E. Bartell, T.B. Bistodeau, R.A. Cediel, K.J. Grove, Larry Zintek, K. E. Lee, L. B. Barber
2008, Aquatic Toxicology (86) 91-98
The synthetic organic compound 4-nonylphenol (NP) has been detected in many human-impacted surface waters in North America. In this study, we examined the ability of NP to alter reproductive competence in male fathead minnows after a 28 day flow-through exposure in a range of...
Mass balance and isotope effects during nitrogen transport through septic tank systems with packed-bed (sand) filters
S.R. Hinkle, J.K. Böhlke, L.H. Fisher
2008, Science of the Total Environment (407) 324-332
Septic tank systems are an important source of NO3− to many aquifers, yet characterization of N mass balance and isotope systematics following septic tank effluent discharge into unsaturated sediments has received limited attention. In this study, samples of septic tank effluent before and after transport through single-pass packed-bed filters...
The importance of hydrology in restoration of bottomland hardwood wetland functions
R.G. Hunter, S.P. Faulkner, K.A. Gibson
2008, Wetlands (28) 605-615
Bottomland hardwood (BLH) forests have important biogeochemical functions and it is well known that certain structural components, including pulsed hydrology, hydric soils, and hydrophytic vegetation, enhance these functions. It is unclear, however, how functions of restored BLH wetlands compare to mature, undisturbed wetlands. We measured a suite of structural and...
Geochemical investigation of weathering processes in a forested headwater catchment: Mass-balance weathering fluxes
B.F. Jones, J.S. Herman
2008, Conference Paper, Mineralogical Magazine
Geochemical research on natural weathering has often been directed towards explanations of the chemical composition of surface water and ground water resulting from subsurface water-rock interactions. These interactions are often defined as the incongruent dissolution of primary silicates, such as feldspar, producing secondary weathering products, such as clay minerals and...
Estimating groundwater recharge in Hebei Plain, China under varying land use practices using tritium and bromide tracers
B. Wang, M. Jin, J. R. Nimmo, L. Yang, W. Wang
2008, Journal of Hydrology (356) 209-222
Tritium and bromide were used as applied tracers to determine groundwater recharge in Hebei Plain, North China, to evaluate the impacts of different soil types, land use, irrigation, and crop cultivation practice on recharge. Additional objectives were to evaluate temporal variability of recharge and the effect on results of the...
Multi-residue method for the analysis of 85 current-use and legacy pesticides in bed and suspended sediments
K.L. Smalling, K.M. Kuivila
2008, Journal of Chromatography A (1210) 8-18
A multi-residue method was developed for the simultaneous determination of 85 current-use and legacy organochlorine pesticides in a single sediment sample. After microwave-assisted extraction, clean-up of samples was optimized using gel permeation chromatography and either stacked carbon and alumina solid-phase extraction cartridges or a deactivated Florisil column. Analytes were determined...
Chemical contaminants, health indicators, and reproductive biomarker responses in fish from rivers in the Southeastern United States
J.E. Hinck, V. S. Blazer, N. D. Denslow, K. R. Echols, R.W. Gale, C. Wieser, T.W. May, M. Ellersieck, J.J. Coyle, D. E. Tillitt
2008, Science of the Total Environment (390) 538-557
Largemouth bass (Micropterus salmoides) and common carp (Cyprinus carpio) were collected from 13 sites located in the Mobile (MRB), Apalachicola–Flint–Chattahoochee (ARB), Savannah (SRB), and Pee Dee (PRB) River Basins to document spatial trends in accumulative chemical contaminants, health indicators, and reproductive biomarkers. Organochlorine residues,...
Decomposition of soil organic matter from boreal black spruce forest: Environmental and chemical controls
K.P. Wickland, J. C. Neff
2008, Biogeochemistry (87) 29-47
Black spruce forests are a dominant covertype in the boreal forest region, and they inhabit landscapes that span a wide range of hydrologic and thermal conditions. These forests often have large stores of soil organic carbon. Recent increases in temperature at northern latitudes may be stimulating decomposition rates of...
Permeability of continental crust influenced by internal and external forcing
S.A. Rojstaczer, S. E. Ingebritsen, D.O. Hayba
2008, Geofluids (8) 128-139
The permeability of continental crust is so highly variable that it is often considered to defy systematic characterization. However, despite this variability, some order has been gleaned from globally compiled data. What accounts for the apparent coherence of mean permeability in the continental crust (and permeability–depth relations) on a very...
Middle to late cenozoic geology, hydrography, and fish evolution in the American Southwest
J.E. Spencer, G.R. Smith, T.E. Dowling
2008, Conference Paper, Special Paper of the Geological Society of America
An evaluation of the poorly understood Cenozoic hydrologic history of the American Southwest using combined geological and biological data yields new insights with implications for tectonic evolution. The Mesozoic Cordilleran orogen next to the continental margin of southwestern North America probably formed the continental divide. Mountain building migrated eastward to...
Acetylene as fast food: Implications for development of life on anoxic primordial earth and in the outer solar system
R.S. Oremland, M.A. Voytek
2008, Astrobiology (8) 45-58
Acetylene occurs, by photolysis of methane, in the atmospheres of jovian planets and Titan. In contrast, acetylene is only a trace component of Earth's current atmosphere. Nonetheless, a methane-rich atmosphere has been hypothesized for early Earth; this atmosphere would also have been...
Understanding the relationship between audiomagnetotelluric data and models, and borehole data in a hydrological environment
D.K. McPhee, L. Pellerin
2008, Conference Paper, SEG Technical Program Expanded Abstracts
Audiomagnetotelluric (AMT) data and resulting models are analyzed with respect to geophysical and geological borehole logs in order to clarify the relationship between the two methodologies of investigation of a hydrological environment. Several profiles of AMT data collected in basins in southwestern United States are being used for groundwater exploration...
NMR and mass spectrometry of phosphorus in wetlands
H. El-Rifai, M. Heerboth, T.E. Gedris, S. Newman, W. Orem, W.T. Cooper
2008, European Journal of Soil Science (59) 517-525
There is at present little information on the long-term stability of phosphorus sequestered in wetlands. Phosphorus sequestered during high loading periods may be relatively unstable and easily remobilized following changes in nutrient status or hydrological regime, but the chemical forms of sequestered phosphorus that do remobilize are largely unknown at...
Reply to comment by J. Szilagyi on "Comparison of 15 evaporation methods applied to a small mountain lake in the northeastern USA" [J. Hydrol. 340 (3-4) (2007) 149-166]
D.O. Rosenberry, T. C. Winter, D.C. Buso, G.E. Likens
2008, Journal of Hydrology (348) 566-567
[No abstract available]...
Isotopic variations of dissolved copper and zinc in stream waters affected by historical mining
David M. Borrok, David Nimick, Richard B. Wanty, William I. Ridley
2008, Geochimica et Cosmochimica Acta (72) 329-344
Zinc and Cu play important roles in the biogeochemistry of natural systems, and it is likely that these interactions result in mass-dependent fractionations of their stable isotopes. In this study, we examine the relative abundances of dissolved Zn and Cu isotopes in a variety of stream waters draining six historical...
Pathogen and chemical transport in the karst limestone of the Biscayne aquifer: 2. Chemical retention from diffusion and slow advection
Allen M. Shapiro, Robert A. Renken, Ronald W. Harvey, Michael R. Zygnerski, David W. Metge
2008, Water Resources Research (44)
A tracer experiment, using a nonreactive tracer, was conducted as part of an investigation of the potential for chemical and pathogen migration to public supply wells that draw groundwater from the highly transmissive karst limestone of the Biscayne aquifer in southeastern Florida. The tracer was injected into the formation over...
A multi-residue method for the analysis of pesticides and pesticide degradates in water using HLB solid-phase extraction and gas chromatography-ion trap mass spectrometry
M.L. Hladik, K.L. Smalling, K.M. Kuivila
2008, Bulletin of Environmental Contamination and Toxicology (80) 139-144
A method was developed for the analysis of over 60 pesticides and degradates in water by HLB solid-phase extraction and gas-chromatography/mass spectrometry. Method recoveries and detection limits were determined using two surface waters with different dissolved organic carbon (DOC) concentrations. In the lower DOC water, recoveries and detection limits...
Determination of dominant biogeochemical processes in a contaminated aquifer-wetland system using multivariate statistical analysis
S. E. Baez-Cazull, J.T. McGuire, I.M. Cozzarelli, M.A. Voytek
2008, Journal of Environmental Quality (37) 30-46
Determining the processes governing aqueous biogeochemistry in a wetland hydrologically linked to an underlying contaminated aquifer is challenging due to the complex exchange between the systems and their distinct responses to changes in precipitation, recharge, and biological activities. To evaluate temporal and spatial processes in the wetland-aquifer system, water samples...
Influences of organic matter and calcification rate on trace elements in aragonitic estuarine bivalve shells
R.K. Takesue, C. R. Bacon, J.K. Thompson
2008, Geochimica et Cosmochimica Acta (72) 5431-5445
A suite of elements (B, Na, Mg, S, K, Ca, V, Mn, Cr, Sr, and Ba) was measured in aragonitic shells of the estuarine bivalve Corbula amurensis, the Asian clam, using the Sensitive High-Resolution Ion MicroProbe with Reverse Geometry (SHRIMP RG). Our initial intent...
Complex seasonal patterns of primary producers at the land-sea interface
J. E. Cloern, A.D. Jassby
2008, Ecology Letters (11) 1294-1303
Seasonal fluctuations of plant biomass and photosynthesis are key features of the Earth system because they drive variability of atmospheric CO2, water and nutrient cycling, and food supply to consumers. There is no inventory of phytoplankton seasonal cycles in nearshore coastal ecosystems where forcings from ocean,...
Reply to comment by T. N. Narasimhan on “A method to estimate groundwater depletion from confining layers”
Christopher E. Neuzil, Leonard F. Konikow
2008, Water Resources Research (44)
We thank T. N. Narasimhan for his comment on our paper [Konikow and Neuzil, 2007] and for extending the discussion with a historical perspective, additional examples, and some considerations we did not discuss, including implications for water management. We support and agree with the thrust of his comments....
