Mount Elbert Gas Hydrate Stratigraphic Test Well, Alaska North Slope: Coring operations, core sedimentology, and lithostratigraphy
K. Rose, R. Boswell, Timothy S. Collett
2011, Marine and Petroleum Geology (28) 311-331
In February 2007, BP Exploration (Alaska), the U.S. Department of Energy, and the U.S. Geological Survey completed the BPXA-DOE-USGS Mount Elbert Gas Hydrate Stratigraphic Test Well (Mount Elbert well) in the Milne Point Unit on the Alaska North Slope. The program achieved its primary goals of validating the pre-drill estimates...
CyberShake: A Physics-Based Seismic Hazard Model for Southern California
R. Graves, T.H. Jordan, S. Callaghan, E. Deelman, Edward H. Field, G. Juve, C. Kesselman, P. Maechling, G. Mehta, K. Milner, D. Okaya, P. Small, K. Vahi
2011, Pure and Applied Geophysics (168) 367-381
CyberShake, as part of the Southern California Earthquake Center’s (SCEC) Community Modeling Environment, is developing a methodology that explicitly incorporates deterministic source and wave propagation effects within seismic hazard calculations through the use of physics-based 3D ground motion simulations. To calculate a waveform-based seismic hazard estimate for a site of...
A behavior-oriented dynamic model for sandbar migration and 2DH evolution
K.D. Splinter, R.A. Holman, Nathaniel G. Plant
2011, Journal of Geophysical Research C: Oceans (116)
A nonlinear model is developed to study the time‐dependent relationship between the alongshore variability of a sandbar, a(t), and alongshore‐averaged sandbar position, xc(t). Sediment transport equations are derived from energetics‐based formulations. A link between this continuous physical representation and a parametric form describing the migration of sandbars of constant shape is established...
The Regionalization of National-Scale SPARROW Models for Stream Nutrients
Gregory E. Schwarz, Richard B. Alexander, Richard A. Smith, Stephen D. Preston
2011, Journal of the American Water Resources Association (47) 1151-1172
This analysis modifies the parsimonious specification of recently published total nitrogen (TN) and total phosphorus (TP) national‐scale SPAtially Referenced Regressions On Watershed attributes models to allow each model coefficient to vary geographically among three major river basins of the conterminous United States. Regionalization of the national models reduces the standard...
A reverse genetics system for the Great Lakes strain of viral hemorrhagic septicemia virus: the NV gene is required for pathogenicity
Arun Ammayappan, Gael Kurath, Tarin M. Thompson, Vikram N. Vakharia
2011, Marine Biotechnology (13) 672-683
Viral hemorrhagic septicemia virus (VHSV), belonging to the genus Novirhabdovirus in the family of Rhabdoviridae, causes a highly contagious disease of fresh and saltwater fish worldwide. Recently, a novel genotype of VHSV, designated IVb, has invaded the Great Lakes in North America, causing large-scale epidemics in wild fish. An efficient...
The efficacy of salvage logging in reducing subsequent fire severity in conifer-dominated forests of Minnesota, USA
S. Fraver, T. Jain, J.B. Bradford, A.W. D’Amato, D. Kastendick, B. Palik, D. Shinneman, J. Stanovick
2011, Ecological Applications (21) 1895-1901
Although primarily used to mitigate economic losses following disturbance, salvage logging has also been justified on the basis of reducing fire risk and fire severity; however, its ability to achieve these secondary objectives remains unclear. The patchiness resulting from a sequence of recent disturbances—blowdown, salvage logging, and wildfire—provided an excellent...
Episodic growth of a Late Cretaceous and Paleogene intrusive complex of pegmatitic leucogranite, Ruby Mountains core complex, Nevada, USA
Keith A. Howard, J. L. Wooden, C. G. Barnes, W. R. Premo, A.W. Snoke, S.-Y. Lee
2011, Geosphere (7) 1220-1248
Gneissic pegmatitic leucogranite forms a dominant component (>600 km3) of the midcrustal infrastructure of the Ruby Mountains–East Humboldt Range core complex (Nevada, USA), and was assembled and modified episodically into a batholithic volume by myriad small intrusions from ca. 92 to 29 Ma. This injection complex consists of deformed sheets...
Feasibility of waveform inversion of Rayleigh waves for shallow shear-wave velocity using a genetic algorithm
C. Zeng, J. Xia, R. D. Miller, G.P. Tsoflias
2011, Journal of Applied Geophysics (75) 648-655
Conventional surface wave inversion for shallow shear (S)-wave velocity relies on the generation of dispersion curves of Rayleigh waves. This constrains the method to only laterally homogeneous (or very smooth laterally heterogeneous) earth models. Waveform inversion directly fits waveforms on seismograms, hence, does not have such a limitation. Waveforms of...
Comparative phylogeography of a coevolved community: Concerted population expansions in Joshua trees and four Yucca moths
C.I. Smith, S. Tank, W. Godsoe, J. Levenick, Espen Strand, T. Esque, O. Pellmyr
2011, PLoS ONE (6)
Comparative phylogeographic studies have had mixed success in identifying common phylogeographic patterns among co-distributed organisms. Whereas some have found broadly similar patterns across a diverse array of taxa, others have found that the histories of different species are more idiosyncratic than congruent. The variation in the results of comparative phylogeographic...
Using a genetic mixture model to study phenotypic traits: Differential fecundity among Yukon river Chinook Salmon
Jeffrey F. Bromaghin, D.F. Evenson, T.H. McLain, Blair G. Flannery
2011, Transactions of the American Fisheries Society (140) 235-249
Fecundity is a vital population characteristic that is directly linked to the productivity of fish populations. Historic data from Yukon River (Alaska) Chinook salmon Oncorhynchus tshawytscha suggest that length‐adjusted fecundity differs among populations within the drainage and either is temporally variable or has declined. Yukon River Chinook salmon have been harvested in...
Estimating water supply arsenic levels in the New England bladder cancer study
J.R. Nuckols, Freeman L.E. Beane, J.H. Lubin, M.S. Airola, D. Baris, J. D. Ayotte, A. Taylor, C. Paulu, M.R. Karagas, J. Colt, M.H. Ward, A.-T. Huang, W. Bress, S. Cherala, D.T. Silverman, K.P. Cantor
2011, Environmental Health Perspectives (119) 1279-1285
Background: Ingestion of inorganic arsenic in drinking water is recognized as a cause of bladder cancer when levels are relatively high (≥ 150 µg/L). The epidemiologic evidence is less clear at the low-to-moderate concentrations typically observed in the United States. Accurate retrospective exposure assessment over a long time period is...
Predicting community responses to perturbations in the face of imperfect knowledge and network complexity
M. Novak, J.T. Wootton, D.F. Doak, M. Emmerson, J. A. Estes, M. T. Tinker
2011, Ecology (92) 836-846
How best to predict the effects of perturbations to ecological communities has been a long-standing goal for both applied and basic ecology. This quest has recently been revived by new empirical data, new analysis methods, and increased computing speed, with the promise that ecologically important insights may be obtainable from...
East Antarctic rifting triggers uplift of the Gamburtsev Mountains
Fausto Ferraccioli, Carol A. Finn, Tom A. Jordan, Robin E. Bell, Lester M. Anderson, Detlef Damaske
2011, Nature (479) 388-392
The Gamburtsev Subglacial Mountains are the least understood tectonic feature on Earth, because they are completely hidden beneath the East Antarctic Ice Sheet. Their high elevation and youthful Alpine topography, combined with their location on the East Antarctic craton, creates a paradox that has puzzled researchers since the mountains were...
A Bayesian network to predict coastal vulnerability to sea level rise
B.T. Gutierrez, N.G. Plant, E.R. Thieler
2011, Journal of Geophysical Research F: Earth Surface (116)
Sea level rise during the 21st century will have a wide range of effects on coastal environments, human development, and infrastructure in coastal areas. The broad range of complex factors influencing coastal systems contributes to large uncertainties in predicting long-term sea level rise impacts. Here we explore and demonstrate the...
Testing earthquake source inversion methodologies
M. Page, P.M. Mai, D. Schorlemmer
2011, Eos, Transactions, American Geophysical Union (92) 75-75
Source Inversion Validation Workshop; Palm Springs, California, 11-12 September 2010; Nowadays earthquake source inversions are routinely performed after large earthquakes and represent a key connection between recorded seismic and geodetic data and the complex rupture process at depth. The resulting earthquake source models quantify the spatiotemporal evolution of ruptures. They...
2-D inner-shelf current observations from a single VHF WEllen RAdar (WERA) station
G. Voulgaris, N. Kumar, K.-W. Gurgel, John C. Warner, Jeffrey H. List
2011, Conference Paper, 2011 IEEE/OES/CWTM 10th working conference on current, waves and turbulence measurement, CWTM 2011
The majority of High Frequency (HF) radars used worldwide operate at medium to high frequencies (8 to 30 MHz) providing spatial resolutions ranging from 3 to 1.5 km and ranges from 150 to 50 km. This paper presents results from the deployment of a single Very High Frequency (VHF, 48...
Sensitivity of leaf size and shape to climate: Global patterns and paleoclimatic applications
D.J. Peppe, D.L. Royer, B. Cariglino, S.Y. Oliver, S. Newman, E. Leight, G. Enikolopov, M. Fernandez-Burgos, F. Herrera, J.M. Adams, E. Correa, E.D. Currano, J.M. Erickson, L.F. Hinojosa, J.W. Hoganson, A. Iglesias, C.A. Jaramillo, K.R. Johnson, G.J. Jordan, N.J.B. Kraft, E.C. Lovelock, C.H. Lusk, U. Niinemets, J. Penuelas, G. Rapson, S.L. Wing, I.J. Wright
2011, New Phytologist (190) 724-739
Paleobotanists have long used models based on leaf size and shape to reconstruct paleoclimate. However, most models incorporate a single variable or use traits that are not physiologically or functionally linked to climate, limiting their predictive power. Further, they often underestimate paleotemperature relative to other proxies.Here we quantify leaf–climate correlations...
Allelopathic cover crop prior to seeding is more important than subsequent grazing/mowing in Grassland establishment
D.G. Milchunas, Mark W. Vandever, L.O. Ball, S. Hyberg
2011, Rangeland Ecology and Management (64) 291-300
The effects of grazing, mowing, and type of cover crop were evaluated in a previous winter wheat–fallow cropland seeded to grassland under the Conservation Reserve Program in eastern Colorado. Prior to seeding, the fallow strips were planted to forage sorghum or wheat in alternating strips (cover crops), with no grazing, moderate to...
A Digital Hydrologic Network Supporting NAWQA MRB SPARROW Modeling--MRB_E2RF1WS
J. W. Brakebill, S.E. Terziotti
2011, Report
A digital hydrologic network was developed to support SPAtially Referenced Regression on Watershed attributes (SPARROW) models within selected regions of the United States. These regions correspond with the U.S. Geological Survey's National Water Quality Assessment (NAWQA) Program Major River Basin (MRB) study units 2, 3, 4, 5, and 7 (Preston...
Are patterns in nutrient limitation belowground consistent with those aboveground: Results from a 4 million year chronosequence
Sasha C. Reed, P.M. Vitousek, C.C. Cleveland
2011, Biogeochemistry (106) 323-336
Accurately predicting the effects of global change on net carbon (C) exchange between terrestrial ecosystems and the atmosphere requires a more complete understanding of how nutrient availability regulates both plant growth and heterotrophic soil respiration. Models of soil development suggest that the nature of nutrient limitation changes over the course...
O2 reduction and denitrification rates in shallow aquifers
Anthony J. Tesoriero, Larry J. Puckett
2011, Water Resources Research (47)
O2 reduction and denitrification rates were determined in shallow aquifers of 12 study areas representing a wide range in sedimentary environments and climatic conditions. Zero‐ and first‐order rates were determined by relating reactant or product concentrations to apparent groundwater age. O2 reduction rates varied widely within and between sites, with zero‐order rates...
Hydrostratigraphic analysis of the MADE site with full-resolution GPR and direct-push hydraulic profiling
M. Dogan, R. L. Van Dam, Geoffrey C. Bohling, J.J. Butler Jr., D.W. Hyndman
2011, Geophysical Research Letters (38)
Full‐resolution 3D Ground‐Penetrating Radar (GPR) data were combined with high‐resolution hydraulic conductivity (K) data from vertical Direct‐Push (DP) profiles to characterize a portion of the highly heterogeneous MAcro Dispersion Experiment (MADE) site. This is an important first step to better understand the influence of aquifer heterogeneities on observed anomalous...
Effects of human-induced alteration of groundwater flow on concentrations of naturally-occurring trace elements at water-supply wells
J. D. Ayotte, Z. Szabo, M. J. Focazio, S. M. Eberts
2011, Applied Geochemistry (26) 747-762
The effects of human-induced alteration of groundwater flow patterns on concentrations of naturally-occurring trace elements were examined in five hydrologically distinct aquifer systems in the USA. Although naturally occurring, these trace elements can exceed concentrations that are considered harmful to human health. The results show that pumping-induced hydraulic gradient changes...
High-frequency Born synthetic seismograms based on coupled normal modes
F. Pollitz
2011, Geophysical Journal International (187) 1420-1442
High-frequency and full waveform synthetic seismograms on a 3-D laterally heterogeneous earth model are simulated using the theory of coupled normal modes. The set of coupled integral equations that describe the 3-D response are simplified into a set of uncoupled integral equations by using the Born approximation to calculate scattered...
Bat ecology and public health surveillance for rabies in an urbanizing region of Colorado
Thomas J. O’Shea, D.J. Neubaum, M.A. Neubaum, Paul M. Cryan, Laura E. Ellison, T.R. Stanley, C. E. Rupprecht, W.J. Pape, R. A. Bowen
2011, Urban Ecosystems (14) 665-697
We describe use of Fort Collins, Colorado, and nearby areas by bats in 2001–2005, and link patterns in bat ecology with concurrent public health surveillance for rabies. Our analyses are based on evaluation of summary statistics, and information-theoretic support for results of simple logistic regression. Based on captures in mist...
