Increased groundwater to stream discharge from permafrost thawing in the Yukon River basin: Potential impacts on lateral export of carbon and nitrogen
Michelle Ann Walvoord, Robert G. Striegl
2007, Geophysical Research Letters (34)
Arctic and subarctic watersheds are undergoing climate warming, permafrost thawing, and thermokarst formation resulting in quantitative shifts in surface water - groundwater interaction at the basin scale. Groundwater currently comprises almost one fourth of Yukon River water discharged to the Bering Sea and contributes 5-10% of the dissolved organic carbon...
The geochemistry of pesticides
Jack E. Barbash
2007, Book chapter, Treatise on geochemistry
The mid-1970s marked a major turning point in human history, for it was at that moment that the ability of the Earth’s ecosystems to absorb most of the biological impacts of human activities appears to have been exceeded by the magnitude of those impacts. This conclusion is based partly upon...
Nutrient vectors and riparian processing: A review with special reference to African semiarid savanna ecosystems
Shayne M. Jacobs, J.S. Bechtold, Harry C. Biggs, N. B. Grimm, S. Lorentz, M.E. McClain, R.J. Naiman, Steven S. Perakis, G. Pinay, M.C. Scholes
2007, Ecosystems (10) 1231-1249
This review article describes vectors for nitrogen and phosphorus delivery to riparian zones in semiarid African savannas, the processing of nutrients in the riparian zone and the effect of disturbance on these processes. Semiarid savannas exhibit sharp seasonality, complex hillslope hydrology and high spatial heterogeneity, all of which ultimately impact...
Preface to the Madison declaration and critical synthesis papers on mercury pollution
James P. Hurley, David P. Krabbenhoft, James G. Wiener, Christopher L. Babiarz
2007, Ambio (36) 2-2
No abstract available....
Alpine debris flows triggered by a 28 July 1999 thunderstorm in the central Front Range, Colorado
J. W. Godt, J. A. Coe
2007, Geomorphology (84) 80-97
On 28 July 1999, about 480 alpine debris flows were triggered by an afternoon thunderstorm along the Continental Divide in Clear Creek and Summit counties in the central Front Range of Colorado. The thunderstorm produced about 43??mm of rain in 4??h, 35??mm of which fell in the first 2??h. Several...
Cytherellid species (Ostracoda) and their significance to the Late Quaternary events in the Santos Basin, Brazil
C.T. Bergue, J.C. Coimbra, T. M. Cronin
2007, Senckenbergiana Maritima (37) 5-12
Four autochthonous cytherellid species (Cytherella serratula (BRADY, 1880), C. hermargentina WHATLEY et al. 1998, C. pleistocenica sp. nov. and C. santosensis sp. nov.) have been identified from two offshore cores (44 samples) within the Santos Basin. The distribution of these ostracodes is controlled by local hydrological conditions such as the...
The lakes of Titan
Ellen R. Stofan, Charles Elachi, Jonathan I. Lunine, Ralf D. Lorenz, B. Stiles, K. L. Mitchell, S. Ostro, Laurence A. Soderblom, C. Wood, H. Zebker, S. Wall, Michael A. Janssen, Randolph L. Kirk, Rosaly Lopes, F. Paganelli, Jani Radebaugh, L. Wye, Y. Anderson, M. Allison, R. Boehmer, P. Callahan, P. Encrenaz, E. Flamini, G. Francescetti, Y. Gim, G. Hamilton, S. Hensley, W.T.K. Johnson, K. Kelleher, D. Muhleman, Philipe Paillou, G. Picardi, F. Posa, L. Roth, R. Seu, S. Shaffer, S. Vetrella, R. West
2007, Nature (445) 61-64
The surface of Saturn’s haze-shrouded moon Titan has long been proposed to have oceans or lakes, on the basis of the stability of liquid methane at the surface1,2. Initial visible3 and radar4,5 imaging failed to find any evidence of an ocean, although abundant evidence was found that flowing liquids have existed on...
A field investigation of phreatophyte‐induced fluctuations in the water table
James J. Butler Jr., Gerard J. Kluitenberg, Donald O. Whittemore, Steven P. Loheide II, Wei Jin, Mark A. Billinger, Xiaoyong Zhan
2007, Water Resources Research (43)
Hydrographs from shallow wells in vegetated riparian zones frequently display a distinctive pattern of diurnal water table fluctuations produced by variations in plant water use. A multisite investigation assessed the major controls on these fluctuations and the ecohydrologic insights that can be gleaned from them. Spatial and temporal variations in...
Comparison of local- to regional-scale estimates of ground-water recharge in Minnesota, USA
G. N. Delin, R. W. Healy, D. L. Lorenz, J. R. Nimmo
2007, Journal of Hydrology (334) 231-249
Regional ground-water recharge estimates for Minnesota were compared to estimates made on the basis of four local- and basin-scale methods. Three local-scale methods (unsaturated-zone water balance, water-table fluctuations (WTF) using three approaches, and age dating of ground water) yielded point estimates of recharge that represent spatial scales from about 1...
Assessing the likely value of gravity and drawdown measurements to constrain estimates of hydraulic conductivity and specific yield during unconfined aquifer testing
Joan B. Blainey, Ty P.A. Ferré, Jeffrey T. Cordova
2007, Water Resources Research (43)
Pumping of an unconfined aquifer can cause local desaturation detectable with high‐resolution gravimetry. A previous study showed that signal‐to‐noise ratios could be predicted for gravity measurements based on a hydrologic model. We show that although changes should be detectable with gravimeters, estimations of hydraulic conductivity and specific yield based on...
Population density, biomass, and age-class structure of the invasive clam Corbicula fluminea in rivers of the lower San Joaquin River watershed, California
Larry R. Brown, Janet K. Thompson, K. Higgins, Lisa V. Lucas
2007, Western North American Naturalist (67) 572-586
Corbicula fluminea is well known as an invasive filter-feeding freshwater bivalve with a variety of effects on ecosystem processes. However, C. fluminea has been relatively unstudied in the rivers of the western United States. In June 2003, we sampled C. fluminea at 16 sites in the San Joaquin River watershed of California, which was invaded...
Use of a watershed model to characterize the fate and transport of fluometuron, a soil-applied cotton herbicide, in surface water
R.H. Coupe
2007, International Journal of Environmental Analytical Chemistry (87) 883-896
The Soil and Water Assessment Tool (SWAT) was used to characterize the fate and transport of fluometuron (a herbicide used on cotton) in the Bogue Phalia Basin in northwestern Mississippi, USA. SWAT is a basin-scale watershed model, able to simulate hydrological, chemical, and sediment transport processes. After adjustments to a...
A simple pore water hydrogen diffusion syringe sampler
Don Vroblesky, Francis H. Chapelle, Paul M. Bradley
2007, Ground Water (45) 798-802
Molecular hydrogen (H2) is an important intermediate product and electron donor in microbial metabolism. Concentrations of dissolved H 2 are often diagnostic of the predominant terminal electron-accepting processes in ground water systems or aquatic sediments. H2 concentrations are routinely measured in ground water monitoring wells but are rarely measured in...
Ammonia-oxidizing bacterial community composition in estuarine and oceanic environments assessed using a functional gene microarray
B.B. Ward, D. Eveillard, Julie D. Kirshtein, J.D. Nelson, Mary A. Voytek, G. A. Jackson
2007, Environmental Microbiology (9) 2522-2538
The relationship between environmental factors and functional gene diversity of ammonia-oxidizing bacteria (AOB) was investigated across a transect from the freshwater portions of the Chesapeake Bay and Choptank River out into the Sargasso Sea. Oligonucleotide probes (70-bp) designed to represent the diversity of ammonia monooxygenase (amoA) genes from Chesapeake Bay...
Ordination of breeding birds in relation to environmental gradients in three southeastern United States floodplain forests
J.S. Wakeley, M.P. Guilfoyle, T. J. Antrobus, R.A. Fischer, W.C. Barrow Jr., P.B. Hamel
2007, Wetlands Ecology and Management (15) 417-439
We used an ordination approach to identify factors important to the organization of breeding bird communities in three floodplains: Cache River, Arkansas (AR), Iatt Creek, Louisiana (LA), and the Coosawhatchie River, South Carolina (SC), USA. We used 5-min point counts to sample birds in each study area each spring from...
Influence of groundwater pumping on streamflow restoration following upstream dam removal
James E. Constantz, Hedeff I. Essaid
2007, Hydrological Processes (21) 2823-2834
We compared streamflow in basins under the combined impacts of an upland dam and groundwater pumping withdrawals, by examining streamflow in the presence and absence of each impact. As a qualitative analysis, inter-watershed streamflow comparisons were performed for several rivers flowing into the east side...
A cold phase of the East Pacific triggers new phytoplankton blooms in San Francisco Bay
James E. Cloern, Alan D. Jassby, Janet K. Thompson, Kathryn Hieb
2007, Proceedings of the National Academy of Sciences of the United States of America (104) 18561-18565
Ecological observations sustained over decades often reveal abrupt changes in biological communities that signal altered ecosystem states. We report a large shift in the biological communities of San Francisco Bay, first detected as increasing phytoplankton biomass and occurrences of new seasonal blooms that began in 1999. This phytoplankton increase is...
Effects of flow diversions on water and habitat quality: Examples from California's highly manipulated Sacramento–San Joaquin Delta
Nancy E. Monsen, James E. Cloern, Jon R. Burau
2007, San Francisco Estuary and Watershed Science (5)
We use selected monitoring data to illustrate how localized water diversions from seasonal barriers, gate operations, and export pumps alter water quality across the Sacramento-San Joaquin Delta (California). Dynamics of water-quality variability are complex because the Delta is a mixing zone of water from the Sacramento and San Joaquin Rivers,...
Evaluation of sulfate reduction at experimentally induced mixing interfaces using small-scale push-pull tests in an aquifer-wetland system
T.A. Kneeshaw, Jennifer T. McGuire, Erik W. Smith, Isabelle M. Cozzarelli
2007, Applied Geochemistry (22) 2618-2629
This paper presents small-scale push–pull tests designed to evaluate the kinetic controls on SO42-">SO42- reduction in situ at mixing interfaces between a wetland and aquifer impacted by landfill leachate at the Norman Landfill research site, Norman, OK. Quantifying the...
Mode of occurrence and environmental mobility of oil-field radioactive material at US Geological Survey research site B, Osage-Skiatook Project, northeastern Oklahoma
Robert A. Zielinski, James R. Budahn
2007, Applied Geochemistry (22) 2125-2137
Two samples of produced-water collected from a storage tank at US Geological Survey research site B, near Skiatook Lake in northeastern Oklahoma, have activity concentrations of dissolved 226Ra and 228Ra that are about 1500 disintegrations/min/L (dpm/L). Produced-water also contains minor amounts of small (5–50 μm) suspended grains of Ra-bearing BaSO4 (barite). Precipitation of radioactive...
Hydrology and subsurface transport of oil-field brine at the U.S. Geological Survey OSPER site "A", Osage County, Oklahoma
William N. Herkelrath, Yousif K. Kharaka, James J. Thordsen, Marvin M. Abbott
2007, Applied Geochemistry (22) 2155-2163
Spillage and improper disposal of saline produced water from oil wells has caused environmental damage at thousands of sites in the United States. In order to improve understanding of the fate and transport of contaminants at these sites, the U.S. Geological...
In situ hydrogen consumption kinetics as an indicator of subsurface microbial activity
S.H. Harris, Richard L. Smith, Joseph M. Suflita
2007, FEMS Microbiology Ecology (60) 220-228
There are few methods available for broadly assessing microbial community metabolism directly within a groundwater environment. In this study, hydrogen consumption rates were estimated from in situ injection/withdrawal tests conducted in two geochemically varying, contaminated aquifers as an approach towards developing such a method. The hydrogen consumption first-order rates varied...
Concentration, UV-spectroscopic characteristics and fractionation of DOC in stormflow from an urban stream, Southern California, USA
John A. Izbicki, Isabel Pimentel, Russell Johnson, George R. Aiken, Jerry Leenheer
2007, Environmental Chemistry (4) 35-48
The composition of dissolved organic carbon (DOC) in stormflow from urban areas has been greatly altered, both directly and indirectly, by human activities and there is concern that there may be public health issues associated with DOC, which has unknown composition from different sources within urban watersheds. This...
Space geodetic observation of expansion of the San Gabriel Valley, California, aquifer system, during heavy rainfall in winter 2004-2005
N.E. King, D. Argus, J. Langbein, D.C. Agnew, G. Bawden, R.S. Dollar, Z. Liu, D. Galloway, E. Reichard, A. Yong, F.H. Webb, Y. Bock, K. Stark, D. Barseghian
2007, Journal of Geophysical Research B: Solid Earth (112)
[1] Starting early in 2005, the positions of GPS stations in the San Gabriel valley region of southern California showed statistically significant departures from their previous behavior. Station LONG moved up by about 47 mm, and nearby stations moved away from LONG by about 10 mm....
Effects of habitat management treatments on plant community composition and biomass in a Montane wetland
Jane E. Austin, Janet R. Keough, W.H. Pyle
2007, Wetlands (27) 570-587
Grazing and burning are commonly applied practices that can impact the diversity and biomass of wetland plant communities. We evaluated the vegetative response of wetlands and adjacent upland grasslands to four treatment regimes (continuous idle, fall prescribed burning followed by idle, annual fall cattle grazing, and rotation of summer grazing...
