A log-normal distribution model for the molecular weight of aquatic fulvic acids
S.E. Cabaniss, Q. Zhou, P.A. Maurice, Y.-P. Chin, G. R. Aiken
2000, Environmental Science & Technology (34) 1103-1109
The molecular weight of humic substances influences their proton and metal binding, organic pollutant partitioning, adsorption onto minerals and activated carbon, and behavior during water treatment. We propose a lognormal model for the molecular weight distribution in aquatic fulvic acids to provide a conceptual framework for studying these size effects....
USGS National Seismic Hazard Maps
A.D. Frankel, C.S. Mueller, T. P. Barnhard, E. V. Leyendecker, R. L. Wesson, S. C. Harmsen, F. W. Klein, D. M. Perkins, N.C. Dickman, S.L. Hanson, M. G. Hopper
2000, Earthquake Spectra (16) 1-19
The U.S. Geological Survey (USGS) recently completed new probabilistic seismic hazard maps for the United States, including Alaska and Hawaii. These hazard maps form the basis of the probabilistic component of the design maps used in the 1997 edition of the NEHRP Recommended Provisions for Seismic Regulations for New Buildings and...
Chlorofluorocarbon dating of herbicide-containing well waters in Fresno and Tulare counties, California
F. Spurlock, K. Burow, N. Dubrovsky
2000, Journal of Environmental Quality (29) 474-483
Simazine, diuron, and bromacil are the most frequently detected currently registered pesticides in California groundwater. These herbicides have been used for several decades in Fresno and Tulare counties, California; however, previous data are inadequate to determine whether the detections are a result of recent or historical applications (i.e., within the...
Terrain analysis of the racetrack basin and the sliding rocks of Death Valley
P. Messina, P. Stoffer
2000, Geomorphology (35) 253-265
The Racetrack Playa's unusual surface features known as sliding rocks have been the subject of an ongoing debate and several mapping projects for half a century, although the causative mechanism remains unresolved. Clasts ranging in volume from large pebbles to medium boulders have, unwitnessed, maneuvered around the nearly flat dry...
The southwestern Alaska mercury belt and its relationship to the circum-Pacific metallogenic mercury province
J. E. Gray, C. A. Gent, L.W. Snee
2000, Polarforschung (68) 187-196
A belt of small but numerous mercury deposits extends for about 500 km in the Kuskokwim River region of southwestern Alaska. The southwestern Alaska mercury belt is part of widespread mercury deposits of the circumPacific region that are similar to other mercury deposits throughout the world because they are epithermal...
Waterfowl research priorities in the northern Great Plains
R. R. Cox Jr., Douglas H. Johnson, M. A. Johnson, R.E. Kirby, J.W. Nelson, R. E. Reynolds
2000, Wildlife Society Bulletin (28) 558-564
It is necessary periodically to identify research priorities so that future research will be directed toward the most pertinent issues in waterfowl ecology and management. To that end, Northern Prairie Wildlife Research Center convened a quorum of experts on the ecology of breeding waterfowl, the Waterfowl Working Group, to 1)...
Bias survival estimates from tag-recovery models where catch-and-release is common, with an example from Atlantic striped bass (Morone saxatilis)
D. R. Smith, K.P. Burnham, D.M. Kahn, X. He, C.J. Goshorn, K.A. Hattala, A.W. Kahnle
2000, Canadian Journal of Fisheries and Aquatic Sciences (57) 886-897
Forest gradient response in Sierran landscapes: the physical template
Dean L. Urban, Carol Miller, Patrick N. Halpin, Nathan L. Stephenson
2000, Landscape Ecology (15) 603-620
Vegetation pattern on landscapes is the manifestation of physical gradients, biotic response to these gradients, and disturbances. Here we focus on the physical template as it governs the distribution of mixed-conifer forests in California's Sierra Nevada. We extended a forest simulation model to examine montane environmental gradients, emphasizing factors affecting...
Response of geese to aircraft disturbances
David H. Ward, Robert A. Stehn, Dirk V. Derksen
2000, Conference Paper, Effects of noise on wildlife conference (Terra Borealis no. 2)
Low-flying aircraft can affect behavior, physiology, and distribution of wildlife (Manci et al., 1988), and over time, may impact a population by reducing survival and reproductive performance. Thus, it is important to identify the particular aspects of overflights that affect animals so that management strategies can be developed to minimize...
Comparison of one and two-dimensional open channel flow models for a small habitat stream
T.J. Waddle, P. Steffler, A. Ghanem, C. Katopodis, A. Locke
2000, Rivers (7) 205-220
No abstract available....
Effect of elevation on distribution of female bats in the Black Hills, South Dakota
P.M. Cryan, M.A. Bogan, J.S. Altenbach
2000, Journal of Mammalogy (81) 719-725
Presumably, reproductive female bats are more constrained by thermoregulatory and energy needs than are males and nonreproductive females. Constraints imposed on reproductive females may limit their geographic distribution relative to other bats. Such constraints likely increase with latitude and elevation. Males of 11 bat species that inhabit the Black Hills...
Combining binary decision tree and geostatistical methods to estimate snow distribution in a mountain watershed
Benjamin Balk, Kelly Elder
2000, Water Resources Research (36) 13-26
We model the spatial distribution of snow across a mountain basin using an approach that combines binary decision tree and geostatistical techniques. In April 1997 and 1998, intensive snow surveys were conducted in the 6.9‐km2 Loch Vale watershed (LVWS), Rocky Mountain National Park, Colorado. Binary decision trees were used to model...
Effects of feeding ration on larval swimming speed and responsiveness to predator attacks: Implications for cohort survival
J.H. Chick, M.J. Van Den Avyle
2000, Canadian Journal of Fisheries and Aquatic Sciences (57) 106-115
We conducted laboratory experiments to examine the effects of feeding ration on the routine swimming speed of larval striped bass (Morone saxatilis) and their responsiveness to simulated-predator attacks. Striped bass were reared in low (7 prey ?? L-1), medium (354 prey ?? L-1), or high (740 prey ?? L-1) prey...
Comparison of conventional K-Ar and 40Ar/39Ar dating of young mafic volcanic rocks
M. A. Lanphere
2000, Quaternary Research (53) 294-301
K-Ar and 40Ar/39Ar ages have been measured on nine mafic volcanic rocks younger than 1 myr from the Snake River Plain (Idaho), Mount Adams (Washington), and Crater Lake (Oregon). The K-Ar ages were calculated from Ar measurements made by isotope dilution and K2O measurements by flame photometry. The 40Ar/39Ar ages...
Moment-tensor solutions estimated using optimal filter theory: Global seismicity, 1998
S.A. Sipkin, C. G. Bufe, M.D. Zirbes
2000, Physics of the Earth and Planetary Interiors (118) 169-179
Moment-tensor solutions, estimated using optimal filter theory, are listed for 204 moderate-to-large size earthquakes that occurred during 1998. (C) 2000 Published by Elsevier Science B.V....
A method for producing digital probabilistic seismic landslide hazard maps
R.W. Jibson, E. L. Harp, J. A. Michael
2000, Engineering Geology (58) 271-289
The 1994 Northridge, California, earthquake is the first earthquake for which we have all of the data sets needed to conduct a rigorous regional analysis of seismic slope instability. These data sets include: (1) a comprehensive inventory of triggered landslides, (2) about 200 strong-motion records of the mainshock, (3) 1:24...
Using a metal detector to determine lead sinker abundance in waterbird habitat
A.E. Duerr, S. DeStefano
2000, Wildlife Society Bulletin (27) 952-958
Waterbirds have died of lead poisoning from ingesting lead fishing sinkers in the United States and Europe. Estimating abundance and distribution of sinkers in the environment will help researchers to understand the potential effects of lead poisoning from sinker ingestion. We used a metal detector to test how environmental conditions...
A field technique for estimating aquifer parameters using flow log data
Frederick L. Paillet
2000, Ground Water (38) 510-521
A numerical model is used to predict flow along intervals between producing zones in open boreholes for comparison with measurements of borehole flow. The model gives flow under quasi-steady conditions as a function of the transmissivity and hydraulic head in an arbitrary number of zones communicating with each other along...
Winter survival of adult female harlequin ducks in relation to history of contamination by the Exxon Valdez oil spill
Daniel Esler, Joel A. Schmutz, R. L. Jarvis, D.M. Mulcahy
2000, Journal of Wildlife Management (64) 839-847
Harlequin duck (Histrionicus histrionicus) life-history characteristics make their populations particularly vulnerable to perturbations during nonbreeding periods. The 1989 Exxon Valdez oil spill was a major perturbation to nonbreeding habitats of harlequin ducks in Prince William Sound, Alaska, which resulted in population injury. To assess the status of population recovery from...
A modern earth narrative: What will be the fate of the biosphere?
R.S. Williams
2000, Technology in Society (22) 303-339
The modern Earth Narrative is the scientific description of the natural and human history of the Earth, and it is based on two fundamental concepts: Deep (or Geologic) Time and Biological Evolution. Changes in the Earth's biosphere and geosphere are discussed from the perspective of natural variability and impacts of...
Determination of hydrologic pathways during snowmelt for alpine/subalpine basins, Rocky Mountain National Park, Colorado
Julie K. Suecker, Joseph N. Ryan, Carol Kendall, Robert D. Jarrett
2000, Water Resources Research (36) 63-75
Alpine/subalpine ecosystems in Rocky Mountain National Park may be sensitive to atmospherically derived acidic deposition. Two‐ and three‐component hydrograph separation analyses and correlation analyses were performed for six basins to provide insight into streamflow generation during snowmelt and to assess basin sensitivity to acidic deposition. Three‐component hydrograph separation results for...
Colorado River sediment transport: 2. Systematic bed‐elevation and grain‐size effects of sand supply limitation
David J. Topping, David M. Rubin, Jonathan M. Nelson, Paul J. Kinzel III, Ingrid C. Corson
2000, Water Resources Research (36) 543-570
The Colorado River in Marble and Grand Canyons displays evidence of annual supply limitation with respect to sand both prior to [Topping et al, this issue] and after the closure of Glen Canyon Dam in 1963. Systematic changes in bed elevation and systematic coupled changes in suspended‐sand concentration and grain...
Pyroclast/snow interactions and thermally driven slurry formation. Part 1: Theory for monodisperse grain beds
J. S. Walder
2000, Bulletin of Volcanology (62) 105-118
Lahars are often produced as pyroclastic flows move over snow. This phenomenon involves a complicated interplay of mechanical and thermal processes that need to be separated to get at the fundamental physics. The thermal physics of pyroclast/snow interactions form the focus of this paper. A theoretical model is developed of...
Quantifying time-varying ground-water discharge and recharge in wetlands of the northern Florida Everglades
Jungyill Choi, Judson W. Harvey
2000, Wetlands (20) 500-511
Developing a more thorough understanding of water and chemical budgets in wetlands depends in part on our ability to quantify time-varying interactions between ground water and surface water. We used a combined water and solute mass balance approach to estimate time-varying ground-water discharge and recharge in the Everglades Nutrient Removal...
Development and application of a comprehensive simulation model to evaluate impacts of watershed structures and irrigation water use on streamflow and groundwater: The case of Wet Walnut Creek Watershed, Kansas, USA
S.R. Ramireddygari, M.A. Sophocleous, J.K. Koelliker, S.P. Perkins, R.S. Govindaraju
2000, Journal of Hydrology (236) 223-246
This paper presents the results of a comprehensive modeling study of surface and groundwater systems, including stream-aquifer interactions, for the Wet Walnut Creek Watershed in west-central Kansas. The main objective of this study was to assess the impacts of watershed structures and irrigation water use on streamflow and groundwater levels,...
