Recent sedimentation patterns within the central Atchafalaya Basin, Louisiana
C.R. Hupp, C. R. Demas, D.E. Kroes, Richard H. Day, T.W. Doyle
2008, Wetlands (28) 125-140
Sediment deposition and storage are important functions of forested bottomlands, yet documentation and interpretation of sedimentation processes in these systems remain incomplete. Our study was located in the central Atchafalaya Basin, Louisiana, a distributary of the Mississippi River and contains the largest contiguously forested riparian wetland in North America, which...
The effects of water-level fluctuations on vegetation in a Lake Huron wetland
D.A. Wilcox, S. J. Nichols
2008, Wetlands (28) 487-501
The diversity and resultant habitat value of wetland plant communities in the Laurentian Great Lake's are dependent on water-level fluctuations of varying frequency and amplitude. Conceptual models have described the response of vegetation to alternating high and low lake levels, but few quantitative studies have documented the changes that occur....
Simulated natural hydrologic regime of an intermountain playa conservation site
J.S. Sanderson, N.B. Kotliar, D.A. Steingraeber, C. Browne
2008, Wetlands (28) 363-377
An intermountain playa wetland preserve in Colorado's San Luis Valley was studied to assess how its current hydrologic function compares to its natural hydrologic regime. Current hydrologic conditions were quantified, and on-site effects of off-site water use were assessed. A water-budget model was developed to simulate an unaltered (i.e., natural)...
Environmental tracers as indicators of karst conduits in groundwater in South Dakota, USA
Andrew J. Long, J.F. Sawyer, L.D. Putnam
2008, Hydrogeology Journal (16) 263-280
Environmental tracers sampled from the carbonate Madison aquifer on the eastern flank of the Black Hills, South Dakota, USA indicated the approximate locations of four major karst conduits. Contamination issues are a major concern because these conduits are characterized by direct connections to sinking streams, high groundwater velocities, and proximity...
Tracing ground water input to base flow using sulfate (S, O) isotopes
A. Gu, F. Gray, C.J. Eastoe, L.M. Norman, O. Duarte, A. Long
2008, Ground Water (46) 502-509
Sulfate (S and O) isotopes used in conjunction with sulfate concentration provide a tracer for ground water contributions to base flow. They are particularly useful in areas where rock sources of contrasting S isotope character are juxtaposed, where water chemistry or H and O isotopes fail to distinguish water sources,...
Diets of Lesser Scaup during spring migration throughout the upper-Midwest are consistent with the spring condition hypothesis
M.J. Anteau, A. D. Afton
2008, Waterbirds (31) 97-106
The spring condition hypothesis (SCH) states that the current decline of the North American scaup population (Lesser [Aythya affinis] and Greater Scaup [A. marila] combined) is due to a decline in quality or availability of scaup foods on wintering, spring migration, or breeding areas that has caused a reduction in...
Population structure and genetic diversity of black redhorse (Moxostoma duquesnei) in a highly fragmented watershed
S.M. Reid, C.C. Wilson, N.E. Mandrak, L.M. Carl
2008, Conservation Genetics (9) 531-546
Dams have the potential to affect population size and connectivity, reduce genetic diversity, and increase genetic differences among isolated riverine fish populations. Previous research has reported adverse effects on the distribution and demographics of black redhorse (Moxostoma duquesnei), a threatened fish species in Canada. However, effects on genetic diversity and...
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...
Wide-area estimates of stand structure and water use of tamarix spp. on the lower colorado river: Implications for restoration and water management projects
P.L. Nagler, E. P. Glenn, K. Didan, J. Osterberg, F. Jordan, J. Cunningham
2008, Restoration Ecology (16) 136-145
Tamarix spp. removal has been proposed to salvage water and allow native vegetation to recolonize western U.S. riparian corridors. We conducted wide-area studies on the Lower Colorado River to answer some of the scientific questions about Tamarix water use and the consequences of removal, combining ground surveys with remote sensing...
Chromium, chromium isotopes and selected trace elements, western Mojave Desert, USA
J. A. Izbicki, J.W. Ball, T.D. Bullen, S. J. Sutley
2008, Applied Geochemistry (23) 1325-1352
Chromium(VI) concentrations in excess of the California Maximum Contaminant Level (MCL) of 50 μg/L occur naturally in alkaline, oxic ground-water in alluvial aquifers in the western Mojave Desert, southern California. The highest concentrations were measured in aquifers eroded from mafic rock, but Cr(VI)...
Occurrence and fate of pesticides in four contrasting agricultural settings in the United States
G. V. Steele, H.M. Johnson, Mark W. Sandstrom, P. D. Capel, J.E. Barbash
2008, Journal of Environmental Quality (37) 1116-1132
Occurrence and fate of 45 pesticides and 40 pesticide degradates were investigated in four contrasting agricultural settings—in Maryland, Nebraska, California, and Washington. Primary crops included corn at all sites, soybeans in Maryland, orchards in California and Washington, and vineyards in Washington. Pesticides and pesticide degradates detected in water samples from...
Hydrography and bottom boundary layer dynamics: Influence on inner shelf sediment mobility, Long Bay, North Carolina
L.A. Davis, L.A. Leonard, G.A. Snedden
2008, Southeastern Geology (45) 97-109
This study examined the hydrography and bottom boundary-layer dynamics of two typical storm events affecting coastal North Carolina (NC); a hurricane and the passages of two small consecutive extratropical storms during November 2005. Two upward-looking 1200-kHz Acoustic Doppler Current Profilers (ADCP) were deployed on the inner shelf in northern Long...
Longitudinal gradients along a reservoir cascade
L.E. Miranda, M.D. Habrat, S. Miyazono
2008, Transactions of the American Fisheries Society (137) 1851-1865
Reservoirs have traditionally been regarded as spatially independent entities rather than as longitudinal segments of a river system that are connected upstream and downstream to the river and other reservoirs. This view has frustrated advancement in reservoir science by impeding adequate organization of available information and by hindering interchanges with...
Remote sensing and GIS approach for water-well site selection, southwest Iran
K. Rangzan, A. Charchi, E. Abshirini, J. Dinger
2008, Environmental & Engineering Geoscience (14) 315-326
The Pabdeh-Lali Anticline of northern Khuzestan province is located in southwestern Iran and occupies 790 km2. This structure is situated in the Zagros folded belt. As a result of well-developed karst systems in the anticlinal axis, the water supply potential is high and is drained by many peripheral springs. However,...
Influence of flow-through and renewal exposures on the toxicity of copper to rainbow trout
P.G. Welsh, J. Lipton, C.A. Mebane, J.C.A. Marr
2008, Ecotoxicology and Environmental Safety (69) 199-208
We examined changes in water chemistry and copper (Cu) toxicity in three paired renewal and flow-through acute bioassays with rainbow trout (Oncorhynchus mykiss). Test exposure methodology influenced both exposure water chemistry and measured Cu toxicity. Ammonia and organic carbon concentrations were higher and the fraction of dissolved Cu lower in...
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...
A characterization of non-biotic environmental features of prairies hosting the Dakota Skipper (Hesperia dacotae, Hesperiidae) across its remaining U.S. range
R.A. Royer, R.A. McKenney, W.E. Newton
2008, Journal of the Lepidopterists' Society (62) 1-17
Within the United States, the Dakota Skipper now occurs only in Minnesota, North Dakota, and South Dakota. In these states it has been associated with margins of glacial lakes and calcareous mesic prairies that host warm-season native grasses. Preliminary geographic information system (GIS) analysis in North Dakota has indicated a...
Environmental occurrence of the enterococcal surface protein (esp) gene is an unreliable indicator of human fecal contamination
M.N. Byappanahalli, K. Przybyla-Kelly, D.A. Shively, R.L. Whitman
2008, Environmental Science & Technology (42) 8014-8020
The enterococcal surface protein (esp) gene found in Enterococcus faecalis and E. faecium has recently been explored as a marker of sewage pollution in recreational waters but its occurrence and distribution in environmental enterococci has not been well-documented. If the esp gene is found in environmental samples, there are potential...
Population genetic structure in Atlantic and Pacific Ocean common murres (Uria aalge): Natural replicate tests of post-Pleistocene evolution
J. A. Morris-Pocock, S.A. Taylor, T.P. Birt, M. Damus, John F. Piatt, K.I. Warheit, Vicki L. Friesen
2008, Molecular Ecology (17) 4859-4873
Understanding the factors that influence population differentiation in temperate taxa can be difficult because the signatures of both historic and contemporary demographics are often reflected in population genetic patterns. Fortunately, analyses based on coalescent theory can help untangle the relative influence of these historic and contemporary factors. Common murres (Uria...
Distribution of icy particles across Enceladus' surface as derived from Cassini-VIMS measurements
R. Jaumann, K. Stephan, G. B. Hansen, R. N. Clark, B. J. Buratti, R. H. Brown, K. H. Baines, S.F. Newman, G. Bellucci, G. Filacchione, A. Coradini, D. P. Cruikshank, C.A. Griffith, C. A. Hibbitts, T. B. McCord, R.M. Nelson, P. D. Nicholson, Christophe Sotin, R. Wagner
2008, Icarus (193) 407-419
The surface of Enceladus consists almost completely of water ice. As the band depths of water ice absorptions are sensitive to the size of particles, absorptions can be used to map variations of icy particles across the surface. The Visual and Infrared Mapping Spectrometer (VIMS) observed Enceladus with a high...
Eddy correlation measurements of submarine groundwater discharge
John Crusius, P. Berg, D.J. Koopmans, L. Erban
2008, Marine Chemistry (109) 77-85
This paper presents a new, non-invasive means of quantifying groundwater discharge into marine waters using an eddy correlation approach. The method takes advantage of the fact that, in virtually all aquatic environments, the dominant mode of vertical transport near the sediment–water interface is turbulent mixing. The technique thus relies on...
Pesticide fate and transport throughout unsaturated zones in five agricultural settings, USA
T.C. Hancock, Mark W. Sandstrom, J. R. Vogel, R.M.T. Webb, E.R. Bayless, J.E. Barbash
2008, Journal of Environmental Quality (37) 1086-1100
Pesticide transport through the unsaturated zone is a function of chemical and soil characteristics, application, and water recharge rate. The fate and transport of 82 pesticides and degradates were investigated at five different agricultural sites. Atrazine and metolachlor, as well as several of the degradates of atrazine, metolachlor, acetochlor, and...
Low-Level detections of halogenated volatile organic compounds in groundwater: Use in vulnerability assessments
Niel Plummer, E. Busenberg, S. M. Eberts, L. M. Bexfield, C. J. Brown, L.S. Fahlquist, B. G. Katz, M.K. Landon
2008, Journal of Hydrologic Engineering (13) 1049-1068
Concentrations of halogenated volatile organic compounds (VOCs) were determined by gas chromatography (GC) with an electron-capture detector (GC-ECD) and by gas chromatography with mass spectrometry (GC-MS) in 109 groundwater samples from five study areas in the United States. In each case, the untreated water sample was used...
Biomorphodynamics: Physical-biological feedbacks that shape landscapes
A.B. Murray, M.A.F. Knaapen, M. Tal, M. L. Kirwan
2008, Water Resources Research (44)
Plants and animals affect morphological evolution in many environments. The term "ecogeomorphology" describes studies that address such effects. In this opinion article we use the term "biomorphodynamics" to characterize a subset of ecogeomorphologic studies: those that investigate not only the effects of organisms on physical processes and morphology but also...
Nitrogen biogeochemistry of submarine groundwater discharge
K.D. Kroeger, M.A. Charette
2008, Limnology and Oceanography (53) 1025-1039
To investigate the role of the seepage zone in transport, chemical speciation, and attenuation of nitrogen loads carried by submarine groundwater discharge, we collected nearshore groundwater samples (n = 328) and examined the distribution and isotopic signature (δ15N) of nitrate and ammonium. In addition, we estimated nutrient fluxes from terrestrial...
