Historical trace element distribution in sediments from the Mississippi River delta
P.W. Swarzenski, M. Baskaran, R.J. Rosenbauer, W. H. Orem
2006, Estuaries and Coasts (29) 1094-1107
Five sediment cores were collected on the shelf of the inner Mississippi Bight in June 2003 for a suite of radionuclides to establish geochronologies and trace elements to examine patterns of contaminant deposition and accumulation. Core sites were chosen to reflect a matrix of variable water depths, proximity to the...
The origin of neap-spring tidal cycles
E.P. Kvale
2006, Marine Geology (235) 5-18
The origin of oceanic tides is a basic concept taught in most introductory college-level sedimentology/geology, oceanography, and astronomy courses. Tides are typically explained in the context of the equilibrium tidal theory model. Yet this model does not take into account real tides in many parts of the world. Not only...
Comet 81P/wild 2 under a microscope
D. Brownlee, P. Tsou, J. Aleon, Alexander C. M. O’D C. M., T. Araki, S. Bajt, G.A. Baratta, R. Bastien, P. Bland, P. Bleuet, J. Borg, J.P. Bradley, A. Brearley, F. Brenker, S. Brennan, J.C. Bridges, N.D. Browning, J.R. Brucato, E. Bullock, M.J. Burchell, H. Busemann, Anna L. Butterworth, M. Chaussidon, A. Cheuvront, M. Chi, M.J. Cintala, B. C. Clark, S.J. Clemett, G. Cody, L. Colangeli, G. Cooper, P. Cordier, C. Daghlian, Z. Dai, L. D’Hendecourt, Z. Djouadi, G. Dominguez, T. Duxbury, J.P. Dworkin, D.S. Ebel, T.E. Economou, S. Fakra, S.A.J. Fairey, S. Fallon, G. Ferrini, T. Ferroir, H. Fleckenstein, C. Floss, G. Flynn, I.A. Franchi, M. Fries, Z. Gainsforth, J.-P. Gallien, M. Genge, M.K. Gilles, P. Gillet, J. Gilmour, D.P. Glavin, M. Gounelle, Monica M. Grady, G.A. Graham, P.G. Grant, S.F. Green, F. Grossemy, L. Grossman, J. N. Grossman, Y. Guan, K. Hagiya, R. Harvey, P. Heck, G.F. Herzog, P. Hoppe, F. Horz, J. Huth, I.D. Hutcheon, K. Ignatyev, H. Ishii, M. Ito, D. Jacob, C. Jacobsen, S. Jacobsen, S. Jones, D. Joswiak, A. Jurewicz, A.T. Kearsley, L.P. Keller, H. Khodja, A.L.D. Kilcoyne, J. Kissel, A. Krot, F. Langenhorst, A. Lanzirotti, L. Le, L.A. Leshin, J. Leitner, L. Lemelle, H. Leroux, M.-C. Liu, K. Luening, I. Lyon, G. MacPherson, M.A. Marcus, K. Marhas, B. Marty, G. Matrajt, K. McKeegan, A. Meibom, V. Mennella, K. Messenger, S. Messenger, T. Mikouchi, S. Mostefaoui, T. Nakamura, T. Nakano, M. Newville, L.R. Nittler, I. Ohnishi, K. Ohsumi, K. Okudaira, D.A. Papanastassiou, R. Palma, M.E. Palumbo, R. O. Pepin, D. Perkins, M. Perronnet, P. Pianetta, W. Rao, F.J.M. Rietmeijer, F. Robert, D. Rost, A. Rotundi, R. Ryan, S.A. Sandford, C.S. Schwandt, T.H. See, D. Schlutter, J. Sheffield-Parker, A. Simionovici, S. Simon, I. Sitnitsky, C.J. Snead, M. K. Spencer, F.J. Stadermann, A. Steele, T. Stephan
2006, Science (314) 1711-1716
The Stardust spacecraft collected thousands of particles from comet 81P/Wild 2 and returned them to Earth for laboratory study. The preliminary examination of these samples shows that the nonvolatile portion of the comet is an unequilibrated assortment of materials that have both presolar and solar system origin. The comet contains...
Can basin-scale recharge be estimated reasonably with water-balance models?
A.E. Faust, T.P.A. Ferre, M.G. Schaap, A.C. Hinnell, Gordon E. Brown Jr.
2006, Vadose Zone Journal (5) 850-855
We examine in-place recharge as an example of the complex, basin-scale hydrologic processes that are being represented with simplified numerical models. The rate and distribution of recharge depend on local meteorological conditions and hydrogeologic properties. The pattern of recharge is defined predominantly by the distribution of net precipitation (precipitation less...
Mallard brood movements, wetland use, and duckling survival during and following a prairie drought
Gary L. Krapu, P.J. Pietz, D.A. Brandt, R. R. Cox Jr.
2006, Journal of Wildlife Management (70) 1436-1444
We used radiotelemetry to study mallard (Anas platyrhynchos) brood movements, wetland use, and duckling survival during a major drought (1988-1992) and during the first 2 years of the subsequent wet period (1993-1994) at 4 51-km2 sites in prairie pothole landscapes in eastern North Dakota, USA. About two-thirds of 69 radiomarked...
Pigs on the plains: Institutional analysis of a Colorado water quality initiative
D. King, N. Burkardt, Lamb B. Lee
2006, International Journal of Public Administration (29) 1411-1430
We used the Legal-Institutional Analysis Model (LIAM) and Advocacy Coalition Framework (ACF) to analyze the campaign over passage of the Colorado Hogs Rule, an initiative passed by the voters in 1998 to require regulation of swine production facilities in Colorado. Used in tandem, LIAM and ACF provided an opportunity to...
Modeling nearshore morphological evolution at seasonal scale
D.-J.R. Walstra, P. Ruggiero, G. Lesser, G. Gelfenbaum
2006, Conference Paper, Coastal Dynamics 2005 - Proceedings of the Fifth Coastal Dynamics International Conference
A process-based model is compared with field measurements to test and improve our ability to predict nearshore morphological change at seasonal time scales. The field experiment, along the dissipative beaches adjacent to Grays Harbor, Washington USA, successfully captured the transition between the high-energy erosive conditions of winter and the low-energy...
Use of borehole radar tomography to monitor steam injection in fractured limestone
C. Gregoire, P. K. Joesten
2006, Near Surface Geophysics (4) 355-365
Borehole radar tomography was used as part of a pilot study to monitor steam‐enhanced remediation of a fractured limestone contaminated with volatile organic compounds at the former Loring Air Force Base, Maine, USA. Radar tomography data were collected using 100‐MHz electric‐dipole antennae before and during steam injection to evaluate whether...
The global abundance and size distribution of lakes, ponds, and impoundments
J. A. Downing, Y.T. Prairie, J. J. Cole, C.M. Duarte, L.J. Tranvik, Robert G. Striegl, W. H. McDowell, Pirkko Kortelainen, N.F. Caraco, J.M. Melack, J. J. Middelburg
2006, Limnology and Oceanography (51) 2388-2397
One of the major impediments to the integration of lentic ecosystems into global environmental analyses has been fragmentary data on the extent and size distribution of lakes, ponds, and impoundments. We use new data sources, enhanced spatial resolution, and new analytical approaches to provide new estimates of the global abundance...
Global phylogeographic limits of Hawaii's avian malaria
J.S. Beadell, F. Ishtiaq, R. Covas, M. Melo, B.H. Warren, C. T. Atkinson, S. Bensch, G.R. Graves, Y.V. Jhala, M.A. Peirce, A.R. Rahmani, D.M. Fonseca, R.C. Fleischer
2006, Proceedings of the Royal Society B: Biological Sciences (273) 2935-2944
The introduction of avian malaria (Plasmodium relictum) to Hawaii has provided a model system for studying the influence of exotic disease on naive host populations. Little is known, however, about the origin or the genetic variation of Hawaii's malaria and traditional classification methods have confounded attempts to place the parasite...
Predicted changes in subyearling fall Chinook salmon rearing and migratory habitat under two drawdown scenarios for John Day Reservoir, Columbia River
K.F. Tiffan, R.D. Garland, D.W. Rondorf
2006, North American Journal of Fisheries Management (26) 894-907
We evaluated the potential effects of two different drawdown scenarios on rearing and migration habitat of subyearling fall Chinook salmon Oncorhynchus tshawytscha in John Day Reservoir on the Columbia River. We compared habitats at normal operating pool elevation with habitats at drawdown to spillway crest elevation and drawdown to the...
The importance of physiological ecology in conservation biology
C.R. Tracy, K.E. Nussear, T. C. Esque, K. Dean-Bradley, L.A. DeFalco, K.T. Castle, L.C. Zimmerman, R.E. Espinoza, A.M. Barber
2006, Conference Paper, Integrative and Comparative Biology
Many of the threats to the persistence of populations of sensitive species have physiological or pathological mechanisms, and those mechanisms are best understood through the inherently integrative discipline of physiological ecology. The desert tortoise was listed under the Endangered Species Act largely due to a newly recognized upper respiratory disease...
Dynamics of seismogenic volcanic extrusion at Mount St Helens in 2004-05
R.M. Iverson, D. Dzurisin, C. A. Gardner, T.M. Gerlach, R.G. LaHusen, M. Lisowski, J. J. Major, S. D. Malone, J.A. Messerich, S.C. Moran, J.S. Pallister, A.I. Qamar, S. P. Schilling, J.W. Vallance
2006, Nature (444) 439-443
The 2004-05 eruption of Mount St Helens exhibited sustained, near-equilibrium behaviour characterized by relatively steady extrusion of a solid dacite plug and nearly periodic shallow earthquakes. Here we present a diverse data set to support our hypothesis that these earthquakes resulted from stick-slip motion along the margins of the plug...
Grassland songbirds in a dynamic management landscape: Behavioral responses and management strategies
N.G. Perlut, A.M. Strong, T.M. Donovan, N. J. Buckley
2006, Ecological Applications (16) 2235-2247
In recent decades, earlier and more frequent harvests of agricultural grasslands have been implicated as a major cause of population declines in grassland songbirds. From 2002 to 2005, in the Champlain Valley of Vermont and New York, USA, we studied the reproductive success of Savannah Sparrows (Passerculus sandwichensis) and Bobolinks...
Simulating the effects of frequent fire on southern california coastal shrublands
A.D. Syphard, J. Franklin, Jon E. Keeley
2006, Ecological Applications (16) 1744-1756
Fire disturbance is a primary agent of change in the mediterranean-climate chaparral shrublands of southern California, USA. However, fire frequency has been steadily increasing in coastal regions due to ignitions at the growing wildland-urban interface. Although chaparral is resilient to a range of fire frequencies, successively short intervals between fires...
New ghost-node method for linking different models with varied grid refinement
S.C. James, J.E. Dickinson, S.W. Mehl, M. C. Hill, S. A. Leake, G.A. Zyvoloski, A.-A. Eddebbarh
2006, Conference Paper, Proceedings of the 11th International High Level Radioactive Waste Management Conference, IHLRWM
A flexible, robust method for linking grids of locally refined ground-water flow models constructed with different numerical methods is needed to address a variety of hydrologic problems. This work outlines and tests a new ghost-node model-linking method for a refined "child" model that is contained within a larger and coarser...
Relationship between shrubs and foods in mountain plover habitat in Park County, Colorado
S.C. Schneider, Michael B. Wunder, F.L. Knopf
2006, Southwestern Naturalist (51) 197-202
We explored habitat use in terms of vegetation structure and potential forage availability for mountain plovers (Charadrius montanus) in Park County, Colorado. We quantified the percentage cover of bare ground, percentage cover of shrubs (Chrysothamnus visadiflorus), linear distance to nearest shrub, arthropod biomass, and grasshopper density for 102 plots of...
Comparison of local grid refinement methods for MODFLOW
S. Mehl, M. C. Hill, S. A. Leake
2006, Conference Paper, Ground Water
Many ground water modeling efforts use a finite-difference method to solve the ground water flow equation, and many of these models require a relatively fine-grid discretization to accurately represent the selected process in limited areas of interest. Use of a fine grid over the entire domain can be computationally prohibitive;...
Effects of floods on fish assemblages in an intermittent prairie stream
N.R. Franssen, K.B. Gido, C.S. Guy, J.A. Tripe, S.J. Shrank, T.R. Strakosh, K.N. Bertrand, C.M. Franssen, K.L. Pitts, C.P. Paukert
2006, Freshwater Biology (51) 2072-2086
1. Floods are major disturbances to stream ecosystems that can kill or displace organisms and modify habitats. Many studies have reported changes in fish assemblages after a single flood, but few studies have evaluated the importance of timing and intensity of floods on long-term fish assemblage dynamics. 2. We used...
Photometric properties of Titan's surface from Cassini VIMS: Relevance to titan's hemispherical albedo dichotomy and surface stability
R.M. Nelson, R. H. Brown, B.W. Hapke, W. D. Smythe, L. Kamp, M.D. Boryta, F. Leader, K. H. Baines, G. Bellucci, J.-P. Bibring, B. J. Buratti, F. Capaccioni, P. Cerroni, R. N. Clark, M. Combes, A. Coradini, D. P. Cruikshank, P. Drossart, V. Formisano, R. Jaumann, Y. Langevin, D. L. Matson, T. B. McCord, V. Mennella, P. D. Nicholson, B. Sicardy, Christophe Sotin
2006, Planetary and Space Science (54) 1540-1551
The Visual and Infrared Mapping Spectrometer (VIMS) instrument on the Cassini Saturn Orbiter returned spectral imaging data as the spacecraft undertook six close encounters with Titan beginning 7 July, 2004. Three of these flybys each produced overlapping coverage of two distinct regions of Titan's surface. Twenty-four points were selected on...
Nature and origin of the hematite-bearing plains of Terra Meridiani based on analyses of orbital and Mars Exploration rover data sets
R. E. Arvidson, F. Poulet, R.V. Morris, J.-P. Bibring, J.F. Bell III, S. W. Squyres, P. R. Christensen, G. Bellucci, B. Gondet, B.L. Ehlmann, W. H. Farrand, R.L. Fergason, M. Golombeck, J.L. Griffes, J. Grotzinger, E.A. Guinness, Kenneth E. Herkenhoff, J. R. Johnson, G. Klingelhofer, Y. Langevin, D. Ming, K. Seelos, R.J. Sullivan, J.G. Ward, S.M. Wiseman, M.J. Wolff
2006, Journal of Geophysical Research E: Planets (111)
The ∼5 km of traverses and observations completed by the Opportunity rover from Endurance crater to the Fruitbasket outcrop show that the Meridiani plains consist of sulfate‐rich sedimentary rocks that are largely covered by poorly‐sorted basaltic aeolian sands and a lag of granule‐sized hematitic concretions. Orbital reflectance spectra obtained by...
Effects of altered temperature and precipitation on desert protozoa associated with biological soil crusts
B.J. Darby, D.C. Housman, A.M. Zaki, Y. Shamout, S.M. Adl, J. Belnap, D.A. Neher
2006, Journal of Eukaryotic Microbiology (53) 507-514
Biological soil crusts are diverse assemblages of bacteria, cyanobacteria, algae, fungi, lichens, and mosses that cover much of arid land soils. The objective of this study was to quantify protozoa associated with biological soil crusts and test the response of protozoa to increased temperature and precipitation as is predicted by...
Slip on the San Andreas fault at Parkfield, California, over two earthquake cycles, and the implications for seismic hazard
J. Murray, J. Langbein
2006, Bulletin of the Seismological Society of America (96)
Parkfield, California, which experienced M 6.0 earthquakes in 1934, 1966, and 2004, is one of the few locales for which geodetic observations span multiple earthquake cycles. We undertake a comprehensive study of deformation over the most recent earthquake cycle and explore the results in the context of geodetic data collected...
Comparison of the historical record of earthquake hazard with seismic-hazard models for New Zealand and the continental United States
Mark W. Stirling, Mark D. Petersen
2006, Bulletin of the Seismological Society of America (96) 1978-1994
We compare the historical record of earthquake hazard experienced at 78 towns and cities (sites) distributed across New Zealand and the continental United States with the hazard estimated from the national probabilistic seismic-hazard (PSH) models for the two countries. The two PSH models are constructed with similar methodologies and data....
Fuel loads, fire regimes, and post-fire fuel dynamics in Florida Keys pine forests
J.P. Sah, M.S. Ross, J.R. Snyder, S. Koptur, H.C. Cooley
2006, International Journal of Wildland Fire (15) 463-478
In forests, the effects of different life forms on fire behavior may vary depending on their contributions to total fuel loads. We examined the distribution of fuel components before fire, their effects on fire behavior, and the effects of fire on subsequent fuel recovery in pine forests within the National...
