Presence of avian influenza viruses in waterfowl and wetlands during summer 2010 in California: Are resident birds a potential reservoir?
V. Henaux, M.D. Samuel, Robert J. Dusek, J. P. Fleskes, Hon S. Ip
2012, PLoS ONE (7)
Although wild waterfowl are the main reservoir for low pathogenic avian influenza viruses (LPAIv), the environment plays a critical role for the circulation and persistence of AIv. LPAIv may persist for extended periods in cold environments, suggesting that waterfowl breeding areas in the northern hemisphere may be an important reservoir...
Hydrological effects of the increased CO2 and climate change in the Upper Mississippi River Basin using a modified SWAT
Y. Wu, S. Liu, O. I. Abdul-Aziz
2012, Climatic Change (110) 977-1003
Increased atmospheric CO2 concentration and climate change may significantly impact the hydrological and meteorological processes of a watershed system. Quantifying and understanding hydrological responses to elevated ambient CO2 and climate change is, therefore, critical for formulating adaptive strategies for an appropriate management of water resources. In this study, the Soil...
Regional scale impacts of Tamarix leaf beetles (Diorhabda carinulata) on the water availability of western U.S. rivers as determined by multi-scale remote sensing methods
Pamela L. Nagler, Tim Brown, Kevin R. Hultine, Charles van Riper III, Daniel W. Bean, Philip E. Dennison, R. Scott Murray, Edward P. Glenn
2012, Remote Sensing of Environment (118) 227-240
Tamarix leaf beetles (Diorhabda carinulata) have been widely released on western U.S. rivers to control introduced shrubs in the genus Tamarix. Part of the motivation to control Tamarix is to salvage water for human use. Information is needed on the impact of beetles on Tamarix seasonal leaf production and subsequent...
Isotopically modified nanoparticles for enhanced detection in bioaccumulation studies
S.K. Misra, A. Dybowska, D. Berhanu, Marie Noele Croteau, Samuel N. Luoma, A.R. Boccaccini, E. Valsami-Jones
2012, Environmental Science & Technology (46) 1216-1222
This work presents results on synthesis of isotopically enriched (99% 65Cu) copper oxide nanoparticles and its application in ecotoxicological studies. 65CuO nanoparticles were synthesized as spheres (7 nm) and rods (7 × 40 nm). Significant differences were observed between the reactivity and dissolution of spherical and rod shaped nanoparticles. The extreme sensitivity...
The use of multiobjective calibration and regional sensitivity analysis in simulating hyporheic exchange
Ramon C. Naranjo, Richard G. Niswonger, Mark Stone, Clinton Davis, Alan McKay
2012, Water Resources Research (48)
We describe an approach for calibrating a two-dimensional (2-D) flow model of hyporheic exchange using observations of temperature and pressure to estimate hydraulic and thermal properties. A longitudinal 2-D heat and flow model was constructed for a riffle-pool sequence to simulate flow paths and flux rates for variable discharge conditions....
Intra- and inter-annual trends in phosphorus loads and comparison with nitrogen loads to Rehoboth Bay, Delaware (USA)
J.A. Volk, J.R. Scudlark, K.B. Savidge, A.S. Andres, R.J. Stenger, W.J. Ullman
2012, Estuarine, Coastal and Shelf Science (96) 139-150
Monthly phosphorus loads from uplands, atmospheric deposition, and wastewater to Rehoboth Bay (Delaware) were determined from October 1998 to April 2002 to evaluate the relative importance of these three sources of P to the Bay. Loads from a representative subwatershed were determined and used in an areal extrapolation to estimate the upland load from the...
Keanakākoʻi Tephra produced by 300 years of explosive eruptions following collapse of Kīlauea's caldera in about 1500 CE
Donald A. Swanson, Timothy R. Rose, Richard S. Fiske, John P. McGeehin
2012, Journal of Volcanology and Geothermal Research (215-216) 8-25
The Keanakākoʻi Tephra at Kīlauea Volcano has previously been interpreted by some as the product of a caldera-forming eruption in 1790 CE. Our study, however, finds stratigraphic and 14C evidence that the tephra instead results from numerous eruptions throughout a 300-year period between about 1500 and 1800. The stratigraphic evidence includes:...
Foraging segregation and genetic divergence between geographically proximate colonies of a highly mobile seabird
Anne E. Wiley, Andreanna J. Welch, P.H. Ostrom, Helen F. James, Craig A. Stricker, R.C. Fleischer, H. Gandhi, Josh Adams, D. G. Ainley, F. Duvall, N. Holmes, D. Hu, S. Judge, J. Penniman, K.A. Swindle
2012, Oecologia (168) 119-130
Foraging segregation may play an important role in the maintenance of animal diversity, and is a proposed mechanism for promoting genetic divergence within seabird species. However, little information exists regarding its presence among seabird populations. We investigated genetic and foraging divergence between two colonies of endangered Hawaiian petrels (Pterodroma sandwichensis)...
Impacts of biofuels production alternatives on water quantity and quality in the Iowa River Basin
Y. Wu, S. Liu
2012, Biomass and Bioenergy (36) 182-191
Corn stover as well as perennial grasses like switchgrass (Panicum virgatum) and miscanthus are being considered as candidates for the second generation biofuel feedstocks. However, the challenges to biofuel development are its effects on the environment, especially water quality. This study evaluates the long-term impacts of biofuel production alternatives (e.g.,...
Automating calibration, sensitivity and uncertainty analysis of complex models using the R package Flexible Modeling Environment (FME): SWAT as an example
Y. Wu, S. Liu
2012, Environmental Modelling and Software (31) 99-109
Parameter optimization and uncertainty issues are a great challenge for the application of large environmental models like the Soil and Water Assessment Tool (SWAT), which is a physically-based hydrological model for simulating water and nutrient cycles at the watershed scale. In this study, we present a comprehensive modeling environment for...
Interlaboratory comparison of real-time pcr protocols for quantification of general fecal indicator bacteria
O.C. Shanks, M. Sivaganesan, L. Peed, C.A. Kelty, A.D. Blackwood, M.R. Greene, R.T. Noble, Rebecca N. Bushon, Erin A. Stelzer, J. Kinzelman, T. Anan'Eva, C. Sinigalliano, D. Wanless, J. Griffith, Y. Cao, S. Weisberg, V.J. Harwood, C. Staley, K.H. Oshima, M. Varma, R.A. Haugland
2012, Environmental Science & Technology (46) 945-953
The application of quantitative real-time PCR (qPCR) technologies for the rapid identification of fecal bacteria in environmental waters is being considered for use as a national water quality metric in the United States. The transition from research tool to a standardized protocol requires information on the reproducibility and sources of...
Tidally driven export of dissolved organic carbon, total mercury, and methylmercury from a mangrove-dominated estuary
Brian A. Bergamaschi, D. P. Krabbenhoft, George Aiken, Eduardo Patino, D.G. Rumbold, William H. Orem
2012, Environmental Science & Technology (46) 1371-1378
The flux of dissolved organic carbon (DOC) from mangrove swamps accounts for 10% of the global terrestrial flux of DOC to coastal oceans. Recent findings of high concentrations of mercury (Hg) and methylmercury (MeHg) in mangroves, in conjunction with the common co-occurrence of DOC and Hg species, have raised concerns...
An approach to regional wetland digital elevation model development using a differential global positioning system and a custom-built helicopter-based surveying system
J. W. Jones, G.B. Desmond, C. Henkle, R. Glover
2012, International Journal of Remote Sensing (33) 450-465
Accurate topographic data are critical to restoration science and planning for the Everglades region of South Florida, USA. They are needed to monitor and simulate water level, water depth and hydroperiod and are used in scientific research on hydrologic and biologic processes. Because large wetland environments and data acquisition challenge...
A new method of calculating electrical conductivity with applications to natural waters
R. Blaine McCleskey, D. Kirk Nordstrom, J. N. Ryan, J. W. Ball
2012, Geochimica et Cosmochimica Acta (77) 369-382
A new method is presented for calculating the electrical conductivity of natural waters that is accurate over a large range of effective ionic strength (0.0004–0.7 mol kg−1), temperature (0–95 °C), pH (1–10), and conductivity (30–70,000 μS cm−1). The method incorporates a reliable set of equations to...
Spatial pattern formation of coastal vegetation in response to external gradients and positive feedbacks affecting soil porewater salinity: A model study
J. Jiang, Donald L. DeAngelis, T. J. Smith III, S.Y. Teh, H. L. Koh
2012, Landscape Ecology (27) 109-119
Coastal vegetation of South Florida typically comprises salinity-tolerant mangroves bordering salinity-intolerant hardwood hammocks and fresh water marshes. Two primary ecological factors appear to influence the maintenance of mangrove/hammock ecotones against changes that might occur due to disturbances. One of these is a gradient in one or more environmental factors. The...
Evaluation of MODFLOW-LGR in connection with a synthetic regional-scale model
T.N. Vilhelmsen, S. Christensen, Steffen W. Mehl
2012, Ground Water (50) 118-132
This work studies costs and benefits of utilizing local‐grid refinement (LGR) as implemented in MODFLOW‐LGR to simulate groundwater flow in a buried tunnel valley interacting with a regional aquifer. Two alternative LGR methods were used: the shared‐node (SN) method and the ghost‐node (GN) method. To conserve flows the SN method...
Modifications to the conduit flow process mode 2 for MODFLOW-2005
Thomas Reimann, S. Birk, C. Rehrl, W. Barclay Shoemaker
2012, Ground Water (50) 144-148
As a result of rock dissolution processes, karst aquifers exhibit highly conductive features such as caves and conduits. Within these structures, groundwater flow can become turbulent and therefore be described by nonlinear gradient functions. Some numerical groundwater flow models explicitly account for pipe hydraulics by coupling the continuum model with...
Photodissolution of soil organic matter
L.M. Mayer, K.R. Thornton, L.L. Schick, J.D. Jastrow, Jennifer W. Harden
2012, Geoderma (170) 314-321
Sunlight has been shown to enhance loss of organic matter from aquatic sediments and terrestrial plant litter, so we tested for similar reactions in mineral soil horizons. Losses of up to a third of particulate organic carbon occurred after continuous exposure to full-strength sunlight for dozens of hours, with similar...
Landscape controls on the timing of spring, autumn, and growing season length in mid-Atlantic forests
A.J. Elmore, S.M. Guinn, B. J. Minsley, A.D. Richardson
2012, Global Change Biology (18) 656-674
The timing of spring leaf development, trajectories of summer leaf area, and the timing of autumn senescence have profound impacts to the water, carbon, and energy balance of ecosystems, and are likely influenced by global climate change. Limited field-based and remote-sensing observations have suggested complex spatial patterns related to geographic...
Response of an algal assemblage to nutrient enrichment and shading in a Hawaiian stream
S.H. Stephens, A.M.D. Brasher, C.M. Smith
2012, Hydrobiologia (683) 135-150
To investigate the effects of nitrate enrichment, phosphate enrichment, and light availability on benthic algae, nutrient-diffusing clay flowerpots were colonized with algae at two sites in a Hawaiian stream during spring and autumn 2002 using a randomized factorial design. The algal assemblage that developed under the experimental conditions was investigated...
Methylation of Hg downstream from the Bonanza Hg mine, Oregon
John E. Gray, Mark E. Hines, David P. Krabbenhoft, Bryn Thoms
2012, Applied Geochemistry (27) 106-114
Speciation of Hg and conversion to methyl-Hg were evaluated in stream sediment, stream water, and aquatic snails collected downstream from the Bonanza Hg mine, Oregon. Total production from the Bonanza mine was >1360t of Hg, during mining from the late 1800s to 1960, ranking it as an intermediate sized Hg...
Oxygen and sulfur isotope systematics of sulfate produced during abiotic and bacterial oxidation of sphalerite and elemental sulfur
N. Balci, B. Mayer, W. C. Pat Shanks III, K.W. Mandernack
2012, Geochimica et Cosmochimica Acta (77) 335-351
Studies of metal sulfide oxidation in acid mine drainage (AMD) systems have primarily focused on pyrite oxidation, although acid soluble sulfides (e.g., ZnS) are predominantly responsible for the release of toxic metals. We conducted a series of biological and abiotic laboratory oxidation experiments with pure and Fe-bearing sphalerite (ZnS &...
Generation and evolution of hydrothermal fluids at Yellowstone: Insights from the Heart Lake Geyser Basin
J. B. Lowenstern, D. Bergfeld, William C. Evans, S. Hurwitz
2012, Geochemistry, Geophysics, Geosystems (13)
We sampled fumaroles and hot springs from the Heart Lake Geyser Basin (HLGB), measured water and gas discharge, and estimated heat and mass flux from this geothermal area in 2009. The combined data set reveals that diverse fluids share an origin by mixing of deep solute-rich parent water with dilute...
Water utilization of the Cretaceous Mussentuchit Member local vertebrate fauna, Cedar Mountain Formation, Utah, USA: Using oxygen isotopic composition of phosphate
C.A. Suarez, Luis A. Gonzalez, G.A. Ludvigson, R.L. Cifelli, E. Tremain
2012, Palaeogeography, Palaeoclimatology, Palaeoecology (313-314) 78-92
While the oxygen isotopic composition of pedogenic carbonate has successfully been used to address the effects of global climate change on the hydrologic cycle, detailed regional paleohydrologic studies are lacking. Since the hydrologic cycle can vary extensively on local or regional scales due to events such as such as...
Spectral definition of the macro-algae Ulva curvata in the back-barrier bays of the Eastern Shore of Virginia, USA
E. Ramsey, A. Rangoonwalaj, M.S. Thomsen, A. Schwarzschild
2012, International Journal of Remote Sensing (33) 586-603
We have developed methods to determine the visible (VIS) to near-infrared (NIR) spectral properties of thalli and epiphytes of bloom-forming and green macrophyte Ulva curvata in back-barrier lagoons in Virginia, USA. A 2% increase in NIR thalli reflectance from winter to summer (ca. 9.5%) matched the drop in summer NIR transmittance (ca....
