Estimating recharge rates with analytic element models and parameter estimation
W. R. Dripps, R. J. Hunt, Marilyn P. Anderson
2006, Ground Water (44) 47-55
Quantifying the spatial and temporal distribution of recharge is usually a prerequisite for effective ground water flow modeling. In this study, an analytic element (AE) code (GFLOW) was used with a nonlinear parameter estimation code (UCODE) to quantify the spatial and temporal distribution of recharge using measured base flows as...
Sulfate deposition in subsurface regolith in Gusev crater, Mars
A. Wang, L.A. Haskin, S. W. Squyres, B.L. Jolliff, L. Crumpler, Ralf Gellert, C. Schroder, Kenneth E. Herkenhoff, J. Hurowitz, N.J. Tosca, W. H. Farrand, R. Anderson, A.T. Knudson
2006, Journal of Geophysical Research E: Planets (111)
Excavating into the shallow Martian subsurface has the potential to expose stratigraphic layers and mature regolith, which may hold a record of more ancient aqueous interactions than those expected under current Martian surface conditions. During the Spirit rover's exploration of Gusev crater, rover wheels were used to dig three trenches...
Determination of uranyl incorporation into biogenic manganese oxides using X-ray absorption spectroscopy and scattering
S.M. Webb, C. C. Fuller, B.M. Tebo, J.R. Bargar
2006, Environmental Science & Technology (40) 771-777
Βiogenic manganese oxides are common and an important source of reactive mineral surfaces in the environment that may be potentially enhanced in bioremediation cases to improve natural attenuation. Experiments were performed in which the uranyl ion, UO22+ (U(VI)), at various concentrations was present during manganese oxide biogenesis. At...
Regional and local species richness in an insular environment: Serpentine plants in California
S. Harrison, H.D. Safford, J.B. Grace, J.H. Viers, K.F. Davies
2006, Ecological Monographs (76) 41-56
We asked how the richness of the specialized (endemic) flora of serpentine rock outcrops in California varies at both the regional and local scales. Our study had two goals: first, to test whether endemic richness is affected by spatial habitat structure (e.g., regional serpentine area, local serpentine outcrop area, regional...
Land-use effects on erosion, sediment yields, and reservoir sedimentation: A case study in the Lago Loiza Basin, Puerto Rico
Allen C. Gellis, Richard M. T. Webb, S. C. McIntyre, William J. Wolfe
2006, Physical Geography (27) 39-69
Lago Loíza impounded in 1953 to supply San Juan, Puerto Rico, with drinking water; by 1994, it had lost 47% of its capacity. To characterize sedimentation in Lago Loíza, a study combining land-use history, hillslope erosion rates, and subbasin sediment yields was conducted. Sedimentation rates during the early part of...
Characterization of sediment trapped by macroalgae on a Hawaiian reef flat
R.E. Stamski, M.E. Field
2006, Estuarine, Coastal and Shelf Science (66) 211-216
Reef researchers studying community shifts in the balance between corals and fleshy macroalgae have noted that algae are often covered with sediment. This study characterizes sediment trapping by macroalgae within a Hawaiian reef habitat and constrains the controls on this process. Sediment-laden macroalgae were sampled and macroalgal cover was assessed...
Presence and distribution of wastewater-derived pharmaceuticals in soil irrigated with reclaimed water
C.A. Kinney, E. T. Furlong, S.L. Werner, J.D. Cahill
2006, Environmental Toxicology and Chemistry (25) 317-326
Three sites in the Front Range of Colorado, USA, were monitored from May through September 2003 to assess the presence and distribution of pharmaceuticals in soil irrigated with reclaimed water derived from urban wastewater. Soil cores were collected monthly, and 19 pharmaceuticals, all of which were...
High REE and Y concentrations in Co-Cu-Au ores of the Blackbird district, Idaho
J. F. Slack
2006, Economic Geology (101) 275-280
Analysis of 11 samples of strata-bound Co-Cu-Au ore from the Blackbird district in Idaho shows previously unknown high concentrations of rare earth elements (REE) and Y, averaging 0.53 wt percent ???REE + Y oxides. Scanning electron microscopy indicates REE and Y residence in monazite, xenotime, and allanite that form complex...
The study of ozone variations in the Las Vegas metropolitan area using remote sensing information and ground observations
G. Xian, M. Crane
2006, Conference Paper, 86th AMS Annual Meeting
Urban development in the Las Vegas Valley, Nevada, has grown rapidly in the past fifty years. Associated with this growth has been a change in landscape from natural cover types to developed urban land mixed with planned vegetation canopy throughout in the metropolitan area. Air quality in the Las Vegas...
Trace element geochemistry and surface water chemistry of the Bon Air coal, Franklin County, Cumberland Plateau, southeast Tennessee
S.A. Shaver, J.C. Hower, C.F. Eble, E.D. McLamb, K. Kuers
2006, International Journal of Coal Geology (67) 47-78
Mean contents of trace elements and ash in channel, bench-column, and dump samples of the abandoned Bon Air coal (Lower Pennsylvanian) in Franklin County, Tennessee are similar to Appalachian COALQUAL mean values, but are slightly lower for As, Fe, Hg, Mn, Na, Th, and U, and slightly higher for ash,...
Scaling uncertainties in estimating canopy foliar maintenance respiration for black spruce ecosystems in Alaska
X. Zhang, A. D. McGuire, Roger W. Ruess
2006, Mitigation and Adaptation Strategies for Global Change (11) 147-174
A major challenge confronting the scientific community is to understand both patterns of and controls over spatial and temporal variability of carbon exchange between boreal forest ecosystems and the atmosphere. An understanding of the sources of variability of carbon processes at fine scales and how these contribute to uncertainties in...
Evidence that sea lamprey control led to recovery of the burbot population in Lake Erie
M.A. Stapanian, C.P. Madenjian, L.D. Witzel
2006, Transactions of the American Fisheries Society (135) 1033-1043
Between 1987 and 2003, the abundance of burbot Lota lota in eastern Lake Erie increased significantly, especially in Ontario waters. We considered four hypotheses to explain this increase: (1) reduced competition with lake trout Salvelinus namaycush, the other major coldwater piscivore in Lake Erie; (2) increased abundance of the two main prey species,...
Origin and significance of clay-coated fractures in mudrock fragments of the SAFOD borehole (Parkfield, California)
A.M. Schleicher, B.A. van der Pluijm, J.G. Solum, L.N. Warr
2006, Geophysical Research Letters (33)
The clay mineralogy and texture of rock fragments from the SAFOD borehole at 3067 m and 3436 m measured depth (MD) was investigated by electron microscopy (SEM, TEM) and X-ray-diffraction (XRD). The washed and ultrasonically cleaned samples show slickenfiber striations and thin films of Ca-K bearing smectite that are formed...
CO2 and CH4 exchanges between land ecosystems and the atmosphere in northern high latitudes over the 21st century
Q. Zhuang, J. M. Melillo, M.C. Sarofim, D. W. Kicklighter, A. D. McGuire, B.S. Felzer, A. Sokolov, R.G. Prinn, P.A. Steudler, S. Hu
2006, Geophysical Research Letters (33)
Terrestrial ecosystems of the northern high latitudes (above 50??N) exchange large amounts of CO2 and CH4 with the atmosphere each year. Here we use a process-based model to estimate the budget of CO 2 and CH4 of the region for current climate conditions and for future scenarios by considering effects...
Upper temperature tolerance of loach minnow under acute, chronic, and fluctuating thermal regimes
A.M. Widmer, C.J. Carveth, Scott A. Bonar, J.R. Simms
2006, Transactions of the American Fisheries Society (135) 755-762
We used four methods to estimate the upper lethal temperature of loach minnow Rhinichthys cobitis: the lethal thermal method (LTM), chronic lethal method (CLM), acclimated chronic exposure (ACE) method with static temperatures, and ACE method with diel temperature fluctuations. The upper lethal temperature of this species ranged between 32??C and...
Red mangrove (Rhizophora mangle) reproduction and seedling colonization after Hurricane Charley: Comparisons of Charlotte Harbor and Tampa Bay
C.E. Proffitt, E.C. Milbrandt, S.E. Travis
2006, Estuaries and Coasts (29) 972-978
Reproductive aspects of life history are known to be important in recovery following disturbance in many plant species although this has not been well studied in mangroves. Hurricane Charley devastated large areas of mangroves in Charlotte Harbor, Florida, in August 2004. We surveyed 6 forests in Charlotte Harbor (2002, 2003,...
Mercury in water and biomass of microbial communities in hot springs of Yellowstone National Park, USA
S.A. King, S. Behnke, K. Slack, D. P. Krabbenhoft, D. Kirk Nordstrom, M.D. Burr, Robert G. Striegl
2006, Applied Geochemistry (21) 1868-1879
Ultra-clean sampling methods and approaches typically used in pristine environments were applied to quantify concentrations of Hg species in water and microbial biomass from hot springs of Yellowstone National Park, features that are geologically enriched with Hg. Microbial populations of chemically-diverse hot springs were also characterized using modern methods in...
Eco-informatics and natural resource management
J.B. Cushing, T. Wilson, A. Borning, L. Delcambre, G. Bowker, Mike Frame, J. Schnase, W. Sonntag, J. Fulop, C. Hert, E. Hovy, J. Jones, E. Landis, C. Schweik, L. Brandt, V. Gregg, S. Spengler
2006, Conference Paper, ACM International Conference Proceeding Series
This project highlight reports on the 2004 workshop [1], as well as follow-up activities in 2005 and 2006, regarding how informatics tools can help manage natural resources and decide policy. The workshop was sponsored jointly by sponsored by the NSF, NBII, NASA, and EPA, and attended by practitioners from government...
Effects of nest density, location, and timing on breeding success of Caspian Terns
Michelle Antolos, D.D. Roby, Donald E. Lyons, Scott K. Anderson, K. Collis
2006, Waterbirds (29) 465-472
One of the proposed benefits of colonial nesting in birds is the protection afforded against avian predators. This advantage may be counter-balanced by the negative effects of intraspecific aggression on breeding success. Effects of nest density, nest location within the colony, and timing of nest initiation on productivity of Caspian...
Evaluation of methods to estimate lake herring spawner abundance in Lake Superior
D.L. Yule, J.D. Stockwell, G.A. Cholwek, L.M. Evrard, S. Schram, M. Seider, M. Symbal
2006, Transactions of the American Fisheries Society (135) 680-694
Historically, commercial fishers harvested Lake Superior lake herring Coregonus artedi for their flesh, but recently operators have targeted lake herring for roe. Because no surveys have estimated spawning female abundance, direct estimates of fishing mortality are lacking. The primary objective of this study was to determine the feasibility of using acoustic techniques...
Evolution of a Holocene delta driven by episodic sediment delivery and coseismic deformation, Puget Sound, Washington, USA
W. A. Barnhardt, B.L. Sherrod
2006, Sedimentology (53) 1211-1228
Episodic, large-volume pulses of volcaniclastic sediment and coseismic subsidence of the coast have influenced the development of a late Holocene delta at southern Puget Sound. Multibeam bathymetry, ground-penetrating radar (GPR) and vibracores were used to investigate the morphologic and stratigraphic evolution of the Nisqually River delta. Two fluvial–deltaic facies are...
Reconstructing depositional processes and history from reservoir stratigraphy: Englebright Lake, Yuba River, northern California
N.P. Snyder, S.A. Wright, Charles N. Alpers, L. E. Flint, C. W. Holmes, D. M. Rubin
2006, Journal of Geophysical Research F: Earth Surface (111)
Reservoirs provide the opportunity to link watershed history with its stratigraphic record. We analyze sediment cores from a northern California reservoir in the context of hydrologic history, watershed management, and depositional processes. Observations of recent depositional patterns, sediment‐transport calculations, and 137Cs geochronology support a conceptual model in which the reservoir delta...
Fire severity and plant age in postfire resprouting of woody plants in sage scrub and chaparral
Jon E. Keeley
2006, Madroño (53) 373-379
Postfire resprouting by woody plants confers a marked advantage in rate of recovery over species that regenerate entirely from seed. However, the predictability of this advantage varies markedly between species, with some showing nearly 100% rootcrown survival and others often much lower. This study examined patterns of fire-caused mortality and...
Cassini observations of flow-like features in western Tui Regio, Titan
J. W. Barnes, R. H. Brown, J. Radebaugh, B. J. Buratti, Christophe Sotin, S. Le Mouelic, S. Rodriguez, E. P. Turtle, J. Perry, R. Clark, K. H. Baines, P. D. Nicholson
2006, Geophysical Research Letters (33)
A large (>3 ?? 104 km2), lobate, 5-??m-bright region seen by Cassini on Titan's leading equatorial region is best explained as a flow field. We discuss observations from the Visual and Infrared Mapping Spectrometer and Imaging Science Subsystem of the feature and present a map of the field. We establish...
The prairie dog as a keystone species
Natasha B. Kotliar, Brian J. Miller, Richard P. Reading, Timothy W. Clark
John L. Hoogland, editor(s)
2006, Book chapter, Conservation of the black-tailed prairie dog: Saving North America's western grasslands
The prairie dog has a pronounced impact on its grassland ecosystem (King 1955; Uresk and Bjugstad 1983; Miller et al. 1994; Society for Conservation Biology 1994; Wuerthner 1997; Johnsgard 2005). They maintain short vegetation by their grazing and by selective removal of tall plants and shrubs; provide shelter, foraging grounds,...
