Extreme plasticity in thermoregulatory behaviors of free-ranging black-tailed prairie dogs
E.M. Lehmer, L.T. Savage, M.F. Antolin, E. Biggins
2006, Physiological and Biochemical Zoology (79) 454-467
In the natural environment, hibernating sciurids generally remain dormant during winter and enter numerous deep torpor bouts from the time of first immergence in fall until emergence in spring. In contrast, black-tailed prairie dogs (Cynomys ludovicianus) remain active throughout winter but periodically enter short and shallow bouts of torpor. While...
A genetic algorithm to reduce stream channel cross section data
C. Berenbrock
2006, Journal of the American Water Resources Association (42) 387-394
A genetic algorithm (GA) was used to reduce cross section data for a hypothetical example consisting of 41 data points and for 10 cross sections on the Kootenai River. The number of data points for the Kootenai River cross sections ranged from about 500 to more than 2,500. The GA...
Characterizing the role benthos plays in large coastal seas and estuaries: A modular approach
K.R. Tenore, R.N. Zajac, J. Terwin, F. Andrade, J. Blanton, W. Boynton, D. Carey, R. Diaz, Austin F. Holland, E. Lopez-Jamar, P. Montagna, F. Nichols, R. Rosenberg, H. Queiroga, M. Sprung, R.B. Whitlatch
2006, Conference Paper, Journal of Experimental Marine Biology and Ecology
Ecologists studying coastal and estuarine benthic communities have long taken a macroecological view, by relating benthic community patterns to environmental factors across several spatial scales. Although many general ecological patterns have been established, often a significant amount of the spatial and temporal variation in soft-sediment communities within and among systems...
Regional intensity attenuation models for France and the estimation of magnitude and location of historical earthquakes
W. H. Bakun, O. Scotti
2006, Geophysical Journal International (164) 596-610
Intensity assignments for 33 calibration earthquakes were used to develop intensity attenuation models for the Alps, Armorican, Provence, Pyrenees and Rhine regions of France. Intensity decreases with ?? most rapidly in the French Alps, Provence and Pyrenees regions, and least rapidly in the Armorican and Rhine regions. The comparable Armorican...
Sensitivity of Last Glacial Maximum climate to uncertainties in tropical and subtropical ocean temperatures
S. Hostetler, N. Pisias, A. Mix
2006, Quaternary Science Reviews (25) 1168-1185
The faunal and floral gradients that underlie the CLIMAP (1981) sea-surface temperature (SST) reconstructions for the Last Glacial Maximum (LGM) reflect ocean temperature gradients and frontal positions. The transfer functions used to reconstruct SSTs from biologic gradients are biased, however, because at the warmest sites they display inherently low sensitivity...
The impact of runoff generation mechanisms on the location of critical source areas
S. W. Lyon, M.R. McHale, M. Walter, T.S. Steenhuis
2006, Journal of the American Water Resources Association (42) 793-804
Identifying phosphorus (P) source areas and transport pathways is a key step in decreasing P loading to natural water systems. This study compared the effects of two modeled runoff generation processes - saturation excess and infiltration excess - on total phosphorus (TP) and soluble reactive phosphorus (SRP) concentrations in 10...
Change in atmospheric mineral aerosols in response to climate: Last glacial period, preindustrial, modern, and doubled carbon dioxide climates
N. M. Mahowald, D.R. Muhs, S. Levis, P.J. Rasch, M. Yoshioka, C.S. Zender, C. Luo
2006, Journal of Geophysical Research D: Atmospheres (111)
Desert dust simulations generated by the National Center for Atmospheric Research's Community Climate System Model for the current climate are shown to be consistent with present day satellite and deposition data. The response of the dust cycle to last glacial maximum, preindustrial, modern, and doubled-carbon dioxide climates is analyzed. Only...
Regional-scale assessment of a sequence-bounding paleosol on fluvial fans using ground-penetrating radar, eastern San Joaquin Valley, California
V.G.L. Bennett, G.S. Weissmann, G.S. Baker, D.W. Hyndman
2006, Geological Society of America Bulletin (118) 724-732
Recently developed sequence stratigraphic models for fluvial fans suggest that sequence boundaries in these deposits are marked by laterally extensive paleosols; however, these models were based on paleosol correlations inferred between wells. To test this, we collected ???190 km of ground-penetrating radar (GPR) profiles on three fluvial fans from the...
Water and solute mass balance of five small, relatively undisturbed watersheds in the U.S.
N.E. Peters, J. B. Shanley, Brent T. Aulenbach, R. M. Webb, K. Campbell, R. Hunt, M. C. Larsen, R.F. Stallard, J. Troester, J.F. Walker
2006, Science of the Total Environment (358) 221-242
Geochemical mass balances were computed for water years 1992-1997 (October 1991 through September 1997) for the five watersheds of the U.S. Geological Survey Water, Energy, and Biogeochemical Budgets (WEBB) Program to determine the primary regional controls on yields of the major dissolved inorganic solutes. The sites, which vary markedly with...
Nitrogen loads to estuaries from waste water plumes: Modeling and isotopic approaches
K.D. Kroeger, Marci L. Cole, J.K. York, I. Valiela
2006, Ground Water (44) 188-200
We developed, and applied in two sites, novel methods to measure ground water-borne nitrogen loads to receiving estuaries from plumes resulting from land disposal of waste water treatment plant (WWTP) effluent. In addition, we quantified nitrogen losses from WWTP effluent during transport through watersheds. WWTP load to receiving water was...
Petrography, palynology, and paleoecology of the Lower Pennsylvanian Bon Air coal, Franklin County, Cumberland Plateau, southeast Tennessee
S.A. Shaver, C.F. Eble, J.C. Hower, F.L. Saussy
2006, International Journal of Coal Geology (67) 17-46
Stratigraphy, palynology, petrography, and geochemistry of the Bon Air coal from the Armfield, Dotson, Rutledge, and Shakerag mine sites of Franklin County, Tennessee suggest that Bon Air seams at all sites were small (??? 1.0 mile, 1.6 km), spatially distinct paleomires that evolved from planar to domed within the fluviodeltaic...
Typing mineral deposits using their associated rocks, grades and tonnages using a probabilistic neural network
D.A. Singer
2006, Mathematical Geology (38) 465-474
A probabilistic neural network is employed to classify 1610 mineral deposits into 18 types using tonnage, average Cu, Mo, Ag, Au, Zn, and Pb grades, and six generalized rock types. The purpose is to examine whether neural networks might serve for integrating geoscience information available in large mineral databases to...
Bias and uncertainty in regression-calibrated models of groundwater flow in heterogeneous media
R.L. Cooley, S. Christensen
2006, Advances in Water Resources (29) 639-656
Groundwater models need to account for detailed but generally unknown spatial variability (heterogeneity) of the hydrogeologic model inputs. To address this problem we replace the large, m-dimensional stochastic vector ?? that reflects both small and large scales of heterogeneity in the inputs by a lumped or smoothed m-dimensional approximation ????*,...
Sample size and the detection of a hump-shaped relationship between biomass and species richness in Mediterranean wetlands
J. L. Espinar
2006, Journal of Vegetation Science (17) 227-232
Questions: What is the observed relationship between biomass and species richness across both spatial and temporal scales in communities of submerged annual macrophytes? Does the number of plots sampled affect detection of hump-shaped pattern? Location: Don??ana National Park, southwestern Spain. Methods: A total of 102 plots were sampled during four...
Explicit use of the Biot coefficient in predicting shear-wave velocity of water-saturated sediments
Myung W. Lee
2006, Geophysical Prospecting (54) 177-185
Predicting the shear-wave (S-wave) velocity is important in seismic modelling, amplitude analysis with offset, and other exploration and engineering applications. Under the low-frequency approximation, the classical Biot-Gassmann theory relates the Biot coefficient to the bulk modulus of water-saturated sediments. If the Biot coefficient under in situ conditions can be estimated,...
Scattered surface wave energy in the seismic coda
Y. Zeng
2006, Pure and Applied Geophysics (163) 533-548
One of the many important contributions that Aki has made to seismology pertains to the origin of coda waves (Aki, 1969; Aki and Chouet, 1975). In this paper, I revisit Aki's original idea of the role of scattered surface waves in the seismic coda. Based on the radiative transfer theory,...
Simulation of solute transport across low-permeability barrier walls
P. T. Harte, Leonard F. Konikow, G.Z. Hornberger
2006, Journal of Contaminant Hydrology (85) 247-270
Low-permeability, non-reactive barrier walls are often used to contain contaminants in an aquifer. Rates of solute transport through such barriers are typically many orders of magnitude slower than rates through the aquifer. Nevertheless, the success of remedial actions may be sensitive to these low rates of transport. Two numerical simulation...
Geophysical monitoring of a field-scale biostimulation pilot project
J.W. Lane Jr., F. D. Day-Lewis, C.C. Casey
2006, Ground Water (44) 430-443
The USGS conducted a geophysical investigation in support of a U.S. Naval Facilities Engineering Command, Southern Division field‐scale biostimulation pilot project at Anoka County Riverfront Park (ACP), downgradient of the Naval Industrial Reserve Ordnance Plant, Fridley, Minnesota. The goal of the pilot project is to evaluate...
Regional patterns in the isotopic composition of natural and anthropogenic nitrate in groundwater, High Plains, U.S.A.
P.B. McMahon, J.K. Böhlke
2006, Environmental Science & Technology (40) 2965-2970
Mobilization of natural nitrate (NO3-) deposits in the subsoil by irrigation water in arid and semiarid regions has the potential to produce large groundwater NO3- concentrations. The use of isotopes to distinguish between natural and anthropogenic NO3- sources in these settings could be complicated by the wide range in δ15N...
Demographic patterns of postfire regeneration in Mediterranean-climate shrublands of California
Jon E. Keeley, C. J. Fotheringham, M. Baer-Keeley
2006, Ecological Monographs (76) 235-255
This study uses detailed demographic data to determine the extent to which functional groupings, based on seedling recruitment and resprouting response to fire, capture the dynamics of postfire responses and early successional change in fire-prone ecosystems. Following massive wildfires in southern California, USA, we sampled chaparral and sage scrub vegetation...
Spatial organization of a reintroduced population of bobcats
Duane R. Diefenbach, L.A. Hansen, R.J. Warren, M.J. Conroy
2006, Journal of Mammalogy (87) 394-401
The spacing patterns and mating systems of solitary carnivores have important implications for social behavior and for the survival and reproduction of individuals. Over 2 years, we reintroduced 32 (15 males and 17 females) bobcats (Lynx rufus) to a barrier island off the coast of Georgia and studied patterns of...
The effect of multiple stressors on salt marsh end-of-season biomass
J.M. Visser, C.E. Sasser, B.S. Cade
2006, Estuaries and Coasts (29) 328-339
It is becoming more apparent that commonly used statistical methods (e.g., analysis of variance and regression) are not the best methods for estimating limiting relationships or stressor effects. A major challenge of estimating the effects associated with a measured subset of limiting factors is to account for the effects of...
Multiple hypotheses testing of fish incidence patterns in an urbanized ecosystem
C.J. Chizinski, C.L. Higgins, C.E. Shavlik, K.L. Pope
2006, Aquatic Ecology (40) 97-109
Ecological and evolutionary theories have focused traditionally on natural processes with little attempt to incorporate anthropogenic influences despite the fact that humans are such an integral part of virtually all ecosystems. A series of alternate models that incorporated anthropogenic factors and traditional ecological mechanisms of invasion to account for fish...
Modeling decadal timescale interactions between surface water and ground water in the central Everglades, Florida, USA
J. W. Harvey, J.T. Newlin, S.L. Krupa
2006, Journal of Hydrology (320) 400-420
Surface-water and ground-water flow are coupled in the central Everglades, although the remoteness of this system has hindered many previous attempts to quantify interactions between surface water and ground water. We modeled flow through a 43,000 ha basin in the central Everglades called Water Conservation Area 2A. The purpose of...
The airborne lava-seawater interaction plume at Kilauea Volcano, Hawai'i
M. Edmonds, T.M. Gerlach
2006, Earth and Planetary Science Letters (244) 83-96
Lava flows into the sea at Kīlauea Volcano, Hawaiʻi, and generates an airborne gas and aerosol plume. Water (H2O), hydrogen chloride (HCl), carbon dioxide (CO2), nitrogen dioxide (NO2) and sulphur dioxide (SO2) gases were quantified in the plume in 2004–2005, using Open Path Fourier Transform infra-red Spectroscopy. The molar abundances...
