Historical perspectives on the concept of ecosystem degradation
W. L. Halvorson
2004, Conference Paper, International Journal of Ecology and Environmental Sciences
The concept of environmental degradation has evolved with the development of human society and settlement. In early human development, tribes went through a series of cycles of taming or developing mastery over the environment, to utilizing the resources of that environment until they could no longer support the population, which...
Modeling the Death Valley regional ground-water flow system
F. A. D’Agnese, C.C. Faunt, M. C. Hill
2004, Conference Paper, Joint Conference on Water Resource Engineering and Water Resources Planning and Management 2000: Building Partnerships
The development of a regional ground-water flow model of the Death Valley region in the southwestern United States is discussed in the context of the fourteen guidelines of Hill. This application of the guidelines demonstrates how they may be used for model calibration and evaluation, and to direct further model...
Local sediment scour model tests for the Woodrow Wilson Bridge piers
D.M. Sheppard, J.S. Jones, M. Odeh, T. Glasser
2004, Conference Paper, Joint Conference on Water Resource Engineering and Water Resources Planning and Management 2000: Building Partnerships
The Woodrow Wilson Bridge on I-495 over the Potomac River in Prince Georges County, Maryland is being replaced. Physical local scour model studies for the proposed piers for the new bridge were performed in order to help establish design scour depths. Tests were conducted in two different flumes, one in...
Using borehole flow data to characterize the hydraulics of flow paths in operating wellfields
F. Paillet, J. Lundy
2004, Conference Paper, Joint Conference on Water Resource Engineering and Water Resources Planning and Management 2000: Building Partnerships
Understanding the flow paths in the vicinity of water well intakes is critical in the design of effective wellhead protection strategies for heterogeneous carbonate aquifers. High-resolution flow logs can be combined with geophysical logs and borehole-wall-image logs (acoustic televiewer) to identify the porous beds, solution openings, and fractures serving as...
Wave run-up on a high-energy dissipative beach
P. Ruggiero, R.A. Holman, R.A. Beach
2004, Journal of Geophysical Research C: Oceans (109)
Because of highly dissipative conditions and strong alongshore gradients in foreshore beach morphology, wave run-up data collected along the central Oregon coast during February 1996 stand in contrast to run-up data currently available in the literature. During a single data run lasting approximately 90 min, the significant vertical run-up elevation...
Recent increases in sediment and nutrient accumulation in Bear Lake, Utah/Idaho, USA
J.M. Smoak, P.W. Swarzenski
2004, Hydrobiologia (525) 175-184
This study examines historical changes in sediment and nutrient accumulation rates in Bear Lake along the northeastern Utah/Idaho border, USA. Two sediment cores were dated by measuring excess 210Pb activities and applying the constant rate of supply (CRS) dating model. Historical rates of bulk sediment accumulation were calculated based on...
Wave- and tidally-driven flow and sediment flux across a fringing coral reef: Southern Molokai, Hawaii
C. D. Storlazzi, A.S. Ogston, Michael H. Bothner, M.E. Field, M.K. Presto
2004, Continental Shelf Research (24) 1397-1419
The fringing coral reef off the south coast of Molokai, Hawaii is currently being studied as part of a US Geological Survey (USGS) multi-disciplinary project that focuses on geologic and oceanographic processes that affect coral reef systems. For this investigation, four instrument packages were deployed across the fringing coral reef...
Upper crustal structure of southwestern British Columbia from the 1998 Seismic Hazards Investigation in Puget Sound
K. Ramachandran, S.E. Dosso, C.A. Zelt, G.D. Spence, R.D. Hyndman, T.M. Brocher
2004, Journal of Geophysical Research B: Solid Earth (109)
This paper applies nonlinear three-dimensional travel time tomography to refraction data recorded during the 1998 Seismic Hazards Investigation in Puget Sound (SHIPS) to derive the first large-scale, high-resolution upper crustal velocity model for southwestern British Columbia. A minimum structure P wave velocity model is constructed using 175,000 first arrival travel...
Wind-related processes detected by the Spirit rover at Gusev crater, Mars
R. Greeley, S. W. Squyres, R. E. Arvidson, P. Bartlett, J.F. Bell III, D. Blaney, N.A. Cabrol, J. Farmer, B. Farrand, M.P. Golombek, S.P. Gorevan, J. A. Grant, A. F. C. Haldemann, Kenneth E. Herkenhoff, J. Johnson, G. Landis, M.B. Madsen, S.H. McLennan, J. Moersch, J. W. Rice Jr., L. Richter, S. Ruff, R.J. Sullivan, S.D. Thompson, A. Wang, C.M. Weitz, P. Whelley
2004, Science (305) 810-821
Wind-abraded rocks, ripples, drifts, and other deposits of windblown sediments are seen at the Columbia Memorial Station where the Spirit rover landed. Orientations of these features suggest formative winds from the north-northwest, consistent with predictions from atmospheric models of afternoon winds in Gusev Crater. Cuttings from the rover Rock Abrasion...
Variance of size-age curves: Bootstrapping with autocorrelation
S.H. Bullock, R. M. Turner, J.R. Hastings, M. Escoto-Rodriguez, Z.R.A. Lopez, J. L. Rodrigues-Navarro
2004, Ecology (85) 2114-2117
We modify a method of estimating size-age relations from a minimal set of individual increment data, recognizing that growth depends not only on size but also varies greatly among individuals and is consistent within an individual for several to many time intervals. The method is exemplified with data from a...
The effects of storms and storm-generated currents on sand beaches in Southern Maine, USA
H.W. Hill, J. T. Kelley, D. F. Belknap, S.M. Dickson
2004, Marine Geology (210) 149-168
Storms are one of the most important controls on the cycle of erosion and accretion on beaches. Current meters placed in shoreface locations of Saco Bay and Wells Embayment, ME, recorded bottom currents during the winter months of 2000 and 2001, while teams of volunteers profiled the topography of nearby...
Pancam multispectral imaging results from the Spirit Rover at Gusev crater
J.F. Bell III, S. W. Squyres, R. E. Arvidson, H.M. Arneson, D. Bass, D. Blaney, N. Cabrol, W. Calvin, J. Farmer, W. H. Farrand, W. Goetz, M. Golombek, J. A. Grant, R. Greeley, E. Guinness, A. G. Hayes, M.Y.H. Hubbard, Kenneth E. Herkenhoff, M. J. Johnson, J. R. Johnson, J. Joseph, K.M. Kinch, M.T. Lemmon, R. Li, M.B. Madsen, J.N. Maki, M. Malin, E. McCartney, S. McLennan, H.Y. McSween Jr., D. W. Ming, J.E. Moersch, R.V. Morris, E.Z.N. Dobrea, T. J. Parker, J. Proton, J. W. Rice Jr., F. Seelos, J. Soderblom, Laurence A. Soderblom, J. N. Sohl-Dickstein, R.J. Sullivan, M.J. Wolff, A. Wang
2004, Science (305) 800-806
Panoramic Camera images at Gusev crater reveal a rock-strewn surface interspersed with high- to moderate-albedo fine-grained deposits occurring in part as drifts or in small circular swales or hollows. Optically thick coatings of fine-grained ferric iron-rich dust dominate most bright soil and rock surfaces. Spectra of some darker rock surfaces...
Flood-formed dunes in Athabasca Valles, Mars: Morphology, modeling, and implications
D.M. Burr, P.A. Carling, R.A. Beyer, N. Lancaster
2004, Icarus (171) 68-83
Estimates of discharge for martian outflow channels have spanned orders of magnitude due in part to uncertainties in floodwater height. A methodology of estimating discharge based on bedforms would reduce some of this uncertainty. Such a methodology based on the morphology and granulometry of flood-formed ('diluvial') dunes has been developed...
Age structure and mortality of walleyes in Kansas reservoirs: Use of mortality caps to establish realistic management objectives
M.C. Quist, J.L. Stephen, C.S. Guy, R.D. Schultz
2004, North American Journal of Fisheries Management (24) 990-1002
Age structure, total annual mortality, and mortality caps (maximum mortality thresholds established by managers) were investigated for walleye Sander vitreus (formerly Stizostedion vitreum) populations sampled from eight Kansas reservoirs during 1991-1999. We assessed age structure by examining the relative frequency of different ages in the population; total annual mortality of...
Re-evaluation of heat flow data near Parkfield, CA: Evidence for a weak San Andreas Fault
P.M. Fulton, D.M. Saffer, Reid N. Harris, B.A. Bekins
2004, Geophysical Research Letters (31)
Improved interpretations of the strength of the San Andreas Fault near Parkfield, CA based on thermal data require quantification of processes causing significant scatter and uncertainty in existing heat flow data. These effects include topographic refraction, heat advection by topographically-driven groundwater flow, and uncertainty in thermal conductivity. Here, we re-evaluate...
Gene expression fingerprints of largemouth bass (Micropterus salmoides) exposed to pulp and paper mill effluents
N. D. Denslow, J. Kocerha, M. S. Sepulveda, Timothy Gross, S. E. Holm
2004, Mutation Research - Fundamental and Molecular Mechanisms of Mutagenesis (552) 19-34
Effluents from pulp and paper mills that historically have used elemental chlorine in the bleaching process have been implicated in inhibiting reproduction in fish. Compounds with estrogenic and androgenic binding affinities have been found in these effluents, suggesting that the impairment of reproduction is through an endocrine-related mode of action....
Geotechnical reconnaissance of the 2002 Denali fault, Alaska, earthquake
R. Kayen, E. Thompson, D. Minasian, R.E.S. Moss, B.D. Collins, N. Sitar, D. Dreger, G. Carver
2004, Earthquake Spectra (20) 639-667
The 2002 M7.9 Denali fault earthquake resulted in 340 km of ruptures along three separate faults, causing widespread liquefaction in the fluvial deposits of the alpine valleys of the Alaska Range and eastern lowlands of the Tanana River. Areas affected by liquefaction are largely confined to Holocene alluvial deposits, man-made...
Surface complexation model of uranyl sorption on Georgia kaolinite
T.E. Payne, J.A. Davis, G.R. Lumpkin, R. Chisari, T.D. Waite
2004, Applied Clay Science (26) 151-162
The adsorption of uranyl on standard Georgia kaolinites (KGa-1 and KGa-1B) was studied as a function of pH (3–10), total U (1 and 10 μmol/l), and mass loading of clay (4 and 40 g/l). The uptake of uranyl in air-equilibrated systems increased with pH and reached...
Visible/near-infrared spectrogoniometric observations and modeling of dust-coated rocks
J. R. Johnson, W.M. Grundy, M.K. Shepard
2004, Icarus (171) 546-556
Interpretations of visible/near-infrared reflectance spectra of Mars are often complicated by the effects of dust coatings that obscure the underlying materials of interest. The ability to separate the spectral reflectance signatures of coatings and substrates requires an understanding of how their individual and combined reflectance properties vary with phase angle....
Response of desert biological soil crusts to alterations in precipitation frequency
J. Belnap, S. L. Phillips, M. E. Miller
2004, Oecologia (141) 306-316
Biological soil crusts, a community of cyanobacteria, lichens, and mosses that live on the soil surface, occur in deserts throughout the world. They are a critical component of desert ecosystems, as they are important contributors to soil fertility and stability. Future climate scenarios predict alteration of the timing and amount...
Has the conversion of natural wetlands to agricultural land increased the incidence and severity of damaging freezes in south Florida?
C. H. Marshall, R.A. Pielke Sr., L. T. Steyaert
2004, Monthly Weather Review (132) 2243-2258
On several occasions, winter freezes have wrought severe destruction on Florida agriculture. A series of devastating freezes around the turn of the twentieth century, and again during the 1980s, were related to anomalies in the large-scale flow of the ocean–atmosphere system. During the twentieth century, substantial areas of wetlands in...
Impact of antecedent climate on fire regimes in coastal California
Jon E. Keeley
2004, International Journal of Wildland Fire (13) 173-182
Severe fire weather is a major determinant of fire size in coastal California; however, it is unclear to what extent antecedent climate also controls fire activity. This study investigates the relationship between fire activity and climate in central coastal and southern California. Climate variables included the Palmer Drought Severity Index...
Geospatial data resampling and resolution effects on watershed modeling: A case study using the agricultural non-point source pollution model
E.L. Usery, M.P. Finn, Daniel J. Scheidt, S. Ruhl, T. Beard, M. Bearden
2004, Journal of Geographical Systems (6) 289-306
Researchers have been coupling geographic information systems (GIS) data handling and processing capability to watershed and waterquality models for many years. This capability is suited for the development of databases appropriate for water modeling. However, it is rare for GIS to provide direct inputs to the models. To demonstrate the...
Linear model describing three components of flow in karst aquifers using 18O data
Andrew J. Long, L.D. Putnam
2004, Journal of Hydrology (296) 254-270
The stable isotope of oxygen, 18O, is used as a naturally occurring ground-water tracer. Time-series data for ??18O are analyzed to model the distinct responses and relative proportions of the conduit, intermediate, and diffuse flow components in karst aquifers. This analysis also describes mathematically the dynamics of the transient fluid...
Subsurface temperature as a passkey for exploration of mature basins: Hot anticlines - A key to discovery?
D. F. Merriam
2004, Oil & Gas Journal (102) 29-34
Temperature anomalies associated with oil-producing structures in the US Midcontinent and similar cratonic areas probably can be used reliably as a passkey for petroleum exploration in mature areas, and thus the concept of hot anticlines could be a key to discovery. Analysis of accumulated data during the past several decades...
