Effects of heterogeneity in aquifer permeability and biomass on biodegradation rate calculations: Results from numerical simulations
Martha A. Scholl
2000, Ground Water (38) 702-712
Numerical simulations were used to examine the effects of heterogeneity in hydraulic conductivity (K) and intrinsic biodegradation rate on the accuracy of contaminant plume‐scale biodegradation rates obtained from field data. The simulations were based on a steady‐state BTEX contaminant plume undergoing biodegradation under sulfate‐reducing conditions, with the electron acceptor in...
Depletion of Appalachian coal reserves - how soon?
R. C. Milici
2000, International Journal of Coal Geology (44) 251-266
Much of the coal consumed in the US since the end of the last century has been produced from the Pennsylvanian strata of the Appalachian basin. Even though quantities mined in the past are less than they are today, this basin yielded from 70% to 80% of the nation's annual...
Geographic patterns and dynamics of Alaskan climate interpolated from a sparse station record
Michael D. Fleming, F. Stuart Chapin III, W. Cramer, Gary L. Hufford, Mark C. Serreze
2000, Global Change Biology (6) 49-58
Data from a sparse network of climate stations in Alaska were interpolated to provide 1-km resolution maps of mean monthly temperature and precipitation-variables that are required at high spatial resolution for input into regional models of ecological processes and resource management. The interpolation model is based on thin-plate smoothing splines,...
Information technology developments within the national biological information infrastructure
Gladys Cotter, Mike Frame
2000, Mathematics and Computers in Modern Science - Acoustics and Music, Biology and Chemistry, Business and Economics 206-211
Looking out an office window or exploring a community park, one can easily see the tremendous challenges that biological information presents the computer science community. Biological information varies in format and content depending whether or not it is information pertaining to a particular species (i.e. Brown Tree Snake), or a...
Methodology and application of combined watershed and ground-water models in Kansas
M. Sophocleous, S.P. Perkins
2000, Journal of Hydrology (236) 185-201
Increased irrigation in Kansas and other regions during the last several decades has caused serious water depletion, making the development of comprehensive strategies and tools to resolve such problems increasingly important. This paper makes the case for an intermediate complexity, quasi-distributed, comprehensive, large-watershed model, which falls between the fully distributed,...
The dependence of permeability on effective stress for an injection test in the Higashi-Hachimantai Geothermal Field
M. Nathenson
2000, Geophysical Research Letters (27) 589-592
A simple inverse-power relation for the influence of effective stress on permeability is used to explain the flow behavior during an injection test at the Higashi-Hachimantai geothermal field, Japan. The new analytical expression successfully models data from the experiment involving high-pressure injection and monitoring at an observation well....
Estimating formation properties from early-time oscillatory water levels in a pumped well
A.M. Shapiro, D.S. Oki
2000, Journal of Hydrology (236) 91-108
Hydrologists often attempt to estimate formation properties from aquifer tests for which only the hydraulic responses in a pumped well are available. Borehole storage, turbulent head losses, and borehole skin, however, can mask the hydraulic behavior of the formation inferred from the water level in the pumped well. Also, in...
Sedimentary record of the 1872 earthquake and "Tsunami" at Owens Lake, southeast California
J. P. Smoot, R. J. Litwin, J. L. Bischoff, S. J. Lund
2000, Sedimentary Geology (135) 241-254
In 1872, a magnitude 7.5-7.7 earthquake vertically offset the Owens Valley fault by more than a meter. An eyewitness reported a large wave on the surface of Owens Lake, presumably initiated by the earthquake. Physical evidence of this event is found in cores and trenches from Owens Lake, including soft-sediment...
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...
Aseismic inflation of Westdahl volcano, Alaska, revealed by satellite radar interferometry
Z. Lu, Charles Wicks, D. Dzurisin, W. Thatcher, J.T. Freymueller, S.R. McNutt, Dorte Mann
2000, Geophysical Research Letters (27) 1567-1570
Westdahl volcano, located at the west end of Unimak Island in the central Aleutian volcanic arc, Alaska, is a broad shield that produced moderate-sized eruptions in 1964, 1978-79, and 1991-92. Satellite radar interferometry detected about 17 cm of volcano-wide inflation from September 1993 to October 1998. Multiple independent interferograms reveal...
Evapotranspiration from a bulrush-dominated wetland in the Klamath Basin, Oregon
W. R. Bidlake
2000, Journal of the American Water Resources Association (36) 1309-1320
Growing-season evapotranspiration and surface energy and water balances were investigated for an extensive, bulrush-dominated wetland in the Upper Klamath National Wildlife Refuge of south-central Oregon, a semi-arid region with competing demands for scarce water resources. Turbulent fluxes of sensible and latent heat were measured by eddy covariance for 1.2 to...
Europa's Crust and Ocean: Origin, Composition, and the Prospects for Life
J.S. Kargel, J.Z. Kaye, J. W. Head III, G.M. Marion, R. Sassen, J.K. Crowley, O.P. Ballesteros, S.A. Grant, D.L. Hogenboom
2000, Icarus (148) 226-265
We have considered a wide array of scenarios for Europa's chemical evolution in an attempt to explain the presence of ice and hydrated materials on its surface and to understand the physical and chemical nature of any ocean that may lie below. We postulate that, following formation of the jovian...
Temporal and spectral characteristics of seismicity observed at Popocatepetl volcano, central Mexico
A. Arciniega-Ceballos, C. Valdes-Gonzalez, P. Dawson
2000, Journal of Volcanology and Geothermal Research (102) 207-216
Popocatepetl volcano entered an eruptive phase from December 21, 1994 to March 30, 1995, which was characterized by ash and fumarolic emissions. During this eruptive episode, the observed seismicity consisted of volcano-tectonic (VT) events, long-period (LP) events and sustained tremor. Before the initial eruption on December 21, VT seismicity exhibited...
Ground deformation associated with the March 1996 earthquake swarm at Akutan volcano, Alaska, revealed by satellite radar interferometry
Z. Lu, C. Wicks Jr., J.A. Power, D. Dzurisin
2000, Journal of Geophysical Research B: Solid Earth (105) 21483-21495
In March 1996 an intense swarm of volcano-tectonic earthquakes (???3000 felt by local residents, Mmax = 5.1, cumulative moment of 2.7 ??1018 N m) beneath Akutan Island in the Aleutian volcanic arc, Alaska, produced extensive ground cracks but no eruption of Akutan volcano. Synthetic aperture radar interferograms that span the...
Sediment distribution and transport along a rocky, embayed coast: Monterey Peninsula and Carmel Bay, California
C. D. Storlazzi, M.E. Field
2000, Marine Geology (170) 289-316
Field measurements of beach morphology and sedimentology were made along the Monterey Peninsula and Carmel Bay, California, in the spring and summer of 1997. These data were combined with low-altitude aerial imagery, high-resolution bathymetry, and local geology to understand how coastal geomorphology, lithology, and tectonics influence the distribution and transport...
Unsaturated‐zone wedge beneath a large, natural lake
Donald O. Rosenberry
2000, Water Resources Research (36) 3401-3409
Lake Belle Taine (480 ha) in north central Minnesota receives on average 76,000 m3 d−1 of water from Little Sand Creek but has no outlet. Water seeps out of the lake, flows through glacial outwash, and discharges into three nearby lakes with stages 13–14 m lower than Belle Taine. Seepage‐meter data indicate...
The 2000 revision of the joint UK/US geomagnetic field models and an IGRF 2000 candidate model
S. Macmillan, J.M. Quinn
2000, Earth, Planets and Space (52) 1149-1162
The method of derivation of the joint UK/US spherical harmonic geomagnetic main-field and secular-variation models is presented. Early versions of these models, with the main field truncated at degree 10, are the UK/US candidates for the IGRF 2000 model. The main-field model describes the Earth’s magnetic field at the 2000.0...
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...
Modelling carbon responses of tundra ecosystems to historical and projected climate: A comparison of a plot- and a global-scale ecosystem model to identify process-based uncertainties
Joy S. Clein, B.L. Kwiatkowski, A. D. McGuire, J.E. Hobbie, E. B. Rastetter, J. M. Melillo, D. W. Kicklighter
2000, Global Change Biology (6) 127-140
We are developing a process-based modelling approach to investigate how carbon (C) storage of tundra across the entire Arctic will respond to projected climate change. To implement the approach, the processes that are least understood, and thus have the most uncertainty, need to be identified and studied. In this paper,...
Influence of a nonionic surfactant (Triton X-100) on contaminant distribution between water and several soil solids
J.-F. Lee, P.-M. Liao, C.-C. Kuo, H.-T. Yang, C. T. Chiou
2000, Journal of Colloid and Interface Science (229) 445-452
The influence of a nonionic surfactant (Triton X-100) on the contaminant distribution coefficients in solid–water mixtures was determined for a number of relatively nonpolar compounds (contaminants) on several natural solids. The studied compounds consisted of BTEX (benzene, toluene, ethylbenzene, and p-xylene) and chlorinated pesticides...
Ecophysiology of wetland plant roots: A modelling comparison of aeration in relation to species distribution
B.K. Sorrell, I.A. Mendelssohn, K.L. McKee, R.A. Woods
2000, Annals of Botany (86) 675-685
This study examined the potential for inter-specific differences in root aeration to determine wetland plant distribution in nature. We compared aeration in species that differ in the type of sediment and depth of water they colonize. Differences in root anatomy, structure and physiology were applied to aeration models that predicted...
An assessment of calcite crystal growth mechanisms based on crystal size distributions
D. E. Kile, D. D. Eberl, A.R. Hoch, M.M. Reddy
2000, Geochimica et Cosmochimica Acta (64) 2937-2950
Calcite crystal growth experiments were undertaken to test a recently proposed model that relates crystal growth mechanisms to the shapes of crystal size distributions (CSDs). According to this approach, CSDs for minerals have three basic shapes: (1) asymptotic, which is related to a crystal growth mechanism having constant-rate nucleation accompanied...
Influence of acid volatile sulfide and metal concentrations on metal bioavailability to marine invertebrates in contaminated sediments
B.-G. Lee, J.-S. Lee, S. N. Luoma, H.J. Choi, C.-H. Koh
2000, Environmental Science & Technology (34) 4517-4523
An 18-day microcosm study was conducted to evaluate the influence of acid volatile sulfides (AVS) and metal additions on bioaccumulation from sediments of Cd, Ni, and Zn in two clams (Macoma balthica and Potamocorbula amurensis) and three marine polychaetes (Neanthes arenaceodentata, Heteromastus filiformis, and Spiophanes missionensis). Manipulation of AVS by oxidation...
A volcano in North Carolina? A closer look at a tall tale
Susan E. Hough
2000, Seismological Research Letters (71) 704-705
The legacy of the 1811-1812 New Madrid, Central United States, earthquakes is one of tremendous enigma. We are left with just enough contemporary information to provide a measure of constraint on the isoseismal contours and therefore magnitudes of the three principal events (Nuttli, 1973; <a class="link...
Annual bed-elevation regime in the alluvial channel of Squamish River, southwestern British Columbia Canada
S.D. Stanford, M.A. Seidl, G.M. Ashley
2000, Earth Surface Processes and Landforms (25) 991-1009
The aim of this study is to examine the annual regime of channel scour and fill by monitoring bed-elevation changes in a reach of Squamish River in southwestern British Columbia, Canada. Sonar surveys of 13 river cross-sections in a sandy gravel-bed single-channel study reach were repeated biweekly over a full...
