Can arsenic occurrence rate in bedrock aquifers be predicted?
Qiang Yang, Hun Bok Jung, Robert G. Marvinney, Charles W. Culbertson, Yan Zheng
2012, Environmental Science & Technology (46) 2080-2087
A high percentage (31%) of groundwater samples from bedrock aquifers in the greater Augusta area, Maine was found to contain greater than 10 μg L–1 of arsenic. Elevated arsenic concentrations are associated with bedrock geology, and more frequently observed in samples with high pH, low dissolved oxygen, and low nitrate. These...
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...
Field experiment provides ground truth for surface nuclear magnetic resonance measurement
R. Knight, E. Grunewald, T. Irons, K. Dlubac, Y. Song, H.N. Bachman, B. Grau, D. Walsh, J.D. Abraham, J. Cannia
2012, Geophysical Research Letters (39) 1-7
The need for sustainable management of fresh water resources is one of the great challenges of the 21st century. Since most of the planet's liquid fresh water exists as groundwater, it is essential to develop non-invasive geophysical techniques to characterize groundwater aquifers. A field experiment was conducted in the High...
A preliminary assessment of the spatial sources of contemporary suspended sediment in the Ohio River basin, United States, using water quality data from the NASQAN programme in a source tracing procedure
Y.-S. Zhang, A.L. Collins, Arthur J. Horowitz
2012, Hydrological Processes (26) 326-334
Reliable information on catchment scale suspended sediment sources is required to inform the design of management strategies for helping abate the numerous environmental issues associated with enhanced sediment mobilization and off‐site loadings. Since sediment fingerprinting techniques avoid many of the logistical constraints associated with using more traditional indirect measurement methods...
Impact of wildfire and slope aspect on soil temperature in a mountainous environment
Brian A. Ebel
2012, Vadose Zone Journal (11)
Soil temperature changes after landscape disturbance impact hydrology, ecology, and geomorphology. This study used field measurements to examine wildfire and aspect effects on soil temperatures. Combustion of the litter and duff layers on north-facing slopes removed pre-fire aspect-driven soil temperature controls.Wildfire is one of the most significant disturbances in mountainous...
Viral hemorrhagic septicemia
William N. Batts, James R. Winton
2012, Book chapter
Viral hemorrhagic septicemia (VHS) is one of the most important viral diseases of finfish worldwide. In the past, VHS was thought to affect mainly rainbow trout Oncorhynchus mykiss reared at freshwater facilities in Western Europe where it was known by various names including Egtved disease and infectious kidney swelling and...
Overwintering tadpoles and loss of fitness correlates in Polypedates braueri tadpoles that use artificial pools in a lowland agroecosystem
Juei-Ling Hsu, Yeong-Choy Kam, Gary M. Fellers
2012, Herpetologica (68) 184-194
We studied growth, development, and metamorphic traits of Polypedates braueri tadpoles in Taiwan to elucidate the cause of tadpole overwintering in man-made water containers in lowland orchards on the Bagua Terrace. Polypedates braueri bred from March to August, but tadpoles were present year round. Laboratory experiments demonstrated that tadpole overwintering...
KINEROS2/AGWA: Model use, calibration and validation
D.C. Goodrich, I.S. Burns, C.L. Unkrich, Darius J. Semmens, D.P. Guertin, M. Hernandez, S. Yatheendradas, Jeffrey R. Kennedy, Lainie R. Levick
2012, Transactions of the ASABE (55) 1561-1574
KINEROS (KINematic runoff and EROSion) originated in the 1960s as a distributed event-based model that conceptualizes a watershed as a cascade of overland flow model elements that flow into trapezoidal channel model elements. KINEROS was one of the first widely available watershed models that interactively coupled a finite difference approximation...
Near‐surface void detection using a seismic landstreamer and horizontal velocity and attenuation tomography
Sean F. Buckley, John W. Lane Jr.
2012, Conference Paper, Symposium on the Application of Geophysics to Engineering and Environmental Problems 2012
The detection and characterization of subsurface voids plays an important role in the study of karst formations and clandestine tunnels. Horizontal velocity and attenuation tomography (HVAT) using offset‐fan shooting and a towed seismic land streamer is a simple, rapid, minimally invasive method that shows promise for detecting near‐surface voids and...
Dissolved organic matter enhances microbial mercury methylation under sulfidic conditions
Andrew M. Graham, George R. Aiken, Cynthia Gilmour
2012, Environmental Science & Technology (46) 2715-2723
Dissolved organic matter (DOM) is generally thought to lower metal bioavailability in aquatic systems due to the formation of metal–DOM complexes that reduce free metal ion concentrations. However, this model may not be pertinent for metal nanoparticles, which are now understood to be ubiquitous, sometimes dominant, metal species in the...
Relationships between Δ14C and the molecular quality of dissolved organic carbon in rivers draining to the coast from the conterminous United States
David Butman, Peter A. Raymond, Kenna D. Butler, George R. Aiken
2012, Global Biogeochemical Cycles (26)
Dissolved organic carbon (DOC) in natural waters possesses chemical and molecular qualities indicative of its source and age. The apportionment of DOC by age into millennial and decadal pools is necessary to understand the temporal connection between terrestrial and aquatic ecosystems in the global carbon cycle. We measured Δ14C-DOC and...
Relating stick-slip friction experiments to earthquake source parameters
Arthur F. McGarr
2012, Geophysical Research Letters (39)
Analytical results for parameters, such as static stress drop, for stick-slip friction experiments, with arbitrary input parameters, can be determined by solving an energy-balance equation. These results can then be related to a given earthquake based on its seismic moment and the maximum slip within its rupture zone, assuming that...
Scientific basis for safely shutting in the Macondo Well after the April 20, 2010 Deepwater Horizon blowout
Stephen H. Hickman, Paul A. Hsieh, Walter D. Mooney, Catherine B. Enomoto, Philip H. Nelson, Larry Mayer, Peter Flemings, Kathryn Moran, Thomas S. Weber, Marcia K. McNutt
James R. Rice, editor(s)
2012, PNAS (109) 20268-20273
As part of the government response to the Deepwater Horizon blowout, a Well Integrity Team evaluated the geologic hazards of shutting in the Macondo Well at the seafloor and determined the conditions under which it could safely be undertaken. Of particular concern was the possibility that, under the anticipated high...
Use of occupancy models to evaluate expert knowledge-based species-habitat relationships
Monica N. Iglecia, Jaime A. Collazo, Alexa McKerrow
2012, Avian Conservation and Ecology (7) 1-13
Expert knowledge-based species-habitat relationships are used extensively to guide conservation planning, particularly when data are scarce. Purported relationships describe the initial state of knowledge, but are rarely tested. We assessed support in the data for suitability rankings of vegetation types based on expert knowledge for three terrestrial avian species in...
Community-level response of fishes and aquatic macroinvertebrates to stream restoration in a third-order tributary of the Potomac River, USA
S.M. Selego, C.L. Rose, G.T. Merovich Jr., Stuart A. Welsh, James T. Anderson
2012, International Journal of Ecology (2012)
Natural stream channel design principles and riparian restoration practices were applied during spring 2010 to an agriculturally impaired reach of the Cacapon River, a tributary of the Potomac River which flows into the Chesapeake Bay. Aquatic macroinvertebrates and fishes were sampled from the restoration reach, two degraded control, and two...
Climate change and human health: Spatial modeling of water availability, malnutrition, and livelihoods in Mali, Africa
Marta M. Jankowska, David Lopez-Carr, Chris Funk, Gregory J. Husak, Z.A. Chafe
2012, Applied Geography (33) 4-15
This study develops a novel approach for projecting climate trends in the Sahel in relation to shifting livelihood zones and health outcomes. Focusing on Mali, we explore baseline relationships between temperature, precipitation, livelihood, and malnutrition in 407 Demographic and Health Survey (DHS) clusters with a total of 14,238 children, resulting...
Grizzly Valley fault system, Sierra Valley, CA
Ryan Gold, William Stephenson, Jack Odum, Rich Briggs, Anthony Crone, Steve Angster
2012, Report, Guidebook: neotectonics of the Lake Tahoe and Carson and Sierra Valleys, F.O.P. 2012
The Grizzly Valley fault system (GVFS) strikes northwestward across Sierra Valley, California and is part of a network of active, dextral strike-slip faults in the northern Walker Lane (Figure 1). To investigate Quaternary motion across the GVFS, we analyzed high-resolution (0.25 m) airborne LiDAR data (Figure 2) in combination with...
Ordovician of the Sauk megasequence in the Ozark region of northern Arkansas and parts of Missouri and adjacent states
Raymond L. Ethington, John E. Repetski, James R. Derby
2012, AAPG Memoir (98) 275-300
Exposures of Ordovician rocks of the Sauk megasequence in Missouri and northern Arkansas comprise Ibexian and lower Whiterockian carbonates with interspersed sandstones. Subjacent Cambrian strata are exposed in Missouri but confined to the subsurface in Arkansas. The Sauk-Tippecanoe boundary in this region is at the base of the St. Peter...
Forest Succession and Maternity Day roost selection by Myotis septentrionalis in a mesophytic hardwood forest
Alexander Silvis, W. Mark Ford, Eric R. Britzke, Nathan R. Beane, Joshua B. Johnson
2012, International Journal of Forestry Research (2012)
Conservation of summer maternity roosts is considered critical for bat management in North America, yet many aspects of the physical and environmental factors that drive roost selection are poorly understood. We tracked 58 female northern bats (Myotis septentrionalis) to 105 roost trees of 21 species on the Fort Knox military...
Synthesis study of an erosion hot spot, Ocean Beach, California
Patrick L. Barnard, Jeff E. Hansen, Li H. Erikson
2012, Journal of Coastal Research (28) 903-922
A synthesis of multiple coastal morphodynamic research efforts is presented to identify the processes responsible for persistent erosion along a 1-km segment of 7-km-long Ocean Beach in San Francisco, California. The beach is situated adjacent to a major tidal inlet and in the shadow of the ebb-tidal delta at the...
Pathogenic human viruses are present in residential canals
Dale W. Griffin
2012, Book chapter, Tropical connections: south Florida's marine environment
No abstract available....
Building on crossvalidation for increasing the quality of geostatistical modeling
Ricardo A. Olea
2012, Stochastic Environmental Research and Risk Assessment (26) 73-82
The random function is a mathematical model commonly used in the assessment of uncertainty associated with a spatially correlated attribute that has been partially sampled. There are multiple algorithms for modeling such random functions, all sharing the requirement of specifying various parameters that have critical influence on the results. The...
Climate model simulations of the mid-Pliocene: Earth's last great interval of global warmth
A.M. Dolan, A.M. Haywood, H.J. Dowsett
2012, Eos, Transactions, American Geophysical Union (93) 18-18
Pliocene Model Intercomparison Project Workshop; Reston, Virginia, 2–4 August 2011 The Pliocene Model Intercomparison Project (PlioMIP), supported by the U.S. Geological Survey's (USGS) Pliocene Research, Interpretation and Synoptic Mapping (PRISM) project and Powell Center, is an integral part of a third iteration of the Paleoclimate Modelling Intercomparison Project (PMIP3). PlioMIP's...
Supplementing seed banks to rehabilitate disturbed Mojave Desert shrublands: Where do all the seeds go?
Lesley A. DeFalco, Todd Esque, Melissa B. Nicklas, Jeffrey M. Kane
2012, Restoration Ecology (20) 85-94
Revegetation of degraded arid lands often involves supplementing impoverished seed banks and improving the seedbed, yet these approaches frequently fail. To understand these failures, we tracked the fates of seeds for six shrub species that were broadcast across two contrasting surface disturbances common to the Mojave Desert—sites compacted by concentrated...
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...
