Tritium-helium 3 dating under complex conditions in hydraulically stressed areas of a buried-valley aquifer
Stephanie Dunkle Shapiro, Gary L. Rowe, Peter Schlosser, Andrea Ludin, Martin Stute
1998, Water Resources Research (34) 1165-1180
The 3H-3He dating method is applied in a buried-valley aquifer near Dayton, Ohio. The study area is large, not all sampling locations lie along well-defined flow paths, and existing wells with variable screen lengths and diameters are used. Reliable use of the method at this site requires addressing several complications: (1)...
Nonlinear refraction and reflection travel time tomography
Jiahua Zhang, Uri S. ten Brink, M.N. Toksoz
1998, Journal of Geophysical Research B: Solid Earth (103) 29743-29757
We develop a rapid nonlinear travel time tomography method that simultaneously inverts refraction and reflection travel times on a regular velocity grid. For travel time and ray path calculations, we apply a wave front method employing graph theory. The first-arrival refraction travel times are calculated on the basis of cell...
Birds of the Indigirka River Delta, Russia: Historical and biogeographic comparisons
John M. Pearce, Daniel Esler, Andrei G. Degtyarev
1998, Arctic (51) 361-370
We documented the breeding status and relative abundance of all avian species on the coastal portion of the Indigirka River Delta during spring and summer 1993-95. Data on avifaunal composition were then compared to data from adjacent areas from Eastern Siberia to the Chukotka Peninsula to evaluate how species composition...
Boron-rich mud volcanoes of the Black Sea region: Modern analogues to ancient sea-floor tourmalinites associated with Sullivan-type Pb-Zn deposits?
J. F. Slack, R.J.W. Turner, P.L.G. Ware
1998, Geology (26) 439-442
Large submarine mud volcanoes in the abyssal part of the Black Sea south of the Crimean Peninsula are similar in many respects to synsedimentary mud volcanoes in the Mesoproterozoic Belt-Purcell basin. One of the Belt-Purcell mud volcanoes directly underlies the giant Sullivan Pb-Zn-Ag...
Classification of surface types using SIR-C/X-SAR, Mount Everest Area, Tibet
Thomas P. Albright, Thomas H. Painter, Dar A. Roberts, Jiancheng Shi, Jeff Dozier, Eric Fielding
1998, Journal of Geophysical Research E: Planets (103) 25823-25833
Imaging radar is a promising tool for mapping snow and ice cover in alpine regions. It combines a high-resolution, day or night, all-weather imaging capability with sensitivity to hydrologic and climatic snow and ice parameters. We use the spaceborne imaging radar-C/X-band synthetic aperture radar (SIR-C/X-SAR) to map snow and glacial...
Degradation of chloroacetanilide herbicides: The prevalence of sulfonic and oxanilic acid metabolites in Iowa groundwaters and surface waters
Stephen J. Kalkhoff, Dana W. Kolpin, E.M. Thurman, I. Ferrer, D. Barcelo
1998, Environmental Science & Technology (32) 1738-1740
Water samples were collected from 88 municipal wells throughout Iowa during the summer and were collected monthly at 12 stream sites in eastern Iowa from March to December 1996 to study the occurrence of the sulfonic and oxanilic metabolites of acetochlor, alachlor, and metolachlor. The sulfonic and oxanilic metabolites were...
Issues and prospects for the next generation of the spatial data transfer standard (SDTS)
D. Arctur, D. Hair, G. Timson, E.P. Martin, R. Fegeas
1998, International Journal of Geographical Information Science (12) 403-425
The Spatial Data Transfer Standard (SDTS) was designed to be capable of representing virtually any data model, rather than being a prescription for a single data model. It has fallen short of this ambitious goal for a number of reasons, which this paper investigates. In addition to issues that might...
Frequency of effective wave activity and the recession of coastal bluffs: Calvert Cliffs, Maryland
P.R. Wilcock, D. S. Miller, R.H. Shea, R.T. Kerkin
1998, Journal of Coastal Research (14) 256-268
The Calvert Cliffs, Chesapeake Bay, Maryland, USA, erode by direct wave undercutting or by freeze/thaw erosion accompanied by wave removal of slope debris. Directly undercut slopes recede more rapidly, with long-term rates exceeding 1.0 m/yr; freeze/thaw slopes recede at rates approaching 0.5 m/yr. The frequency of wave height and water...
Selecting remediation goals by assessing the natural attenuation capacity of groundwater systems
Francis H. Chapelle, Paul M. Bradley
1998, Bioremediation Journal (2) 227-238
Remediation goals for the source areas of a chlorinated ethene‐contaminated groundwater plume were identified by assessing the natural attenuation capacity of the aquifer system. The redox chemistry of the site indicates that sulfate‐reducing (H2 ∼ 2 nanomoles [nM]) per liter conditions near the contaminant source grade to Fe(III)‐reducing conditions (H2...
Riverine based eco-tourism: Trinity River non-market benefits estimates
A. J. Douglas, J. G. Taylor
1998, International Journal of Sustainable Development and World Ecology (5) 136-148
California's Central Valley Project (CVP) was approved by voters in a statewide referendum in 1933. CVP referendum approval initiated funding for construction of important water development projects that had far reaching effects on regional water supplies. The construction of Trinity Dam in 1963 and the subsequent transbasin diversion of Trinity...
Riparian control of stream-water chemistry: Implications for hydrochemical basin models
R. P. Hooper, Brent T. Aulenbach, Douglas A. Burns, J. McDonnell, J. Freer, C. Kendall, K. Beven
1998, IAHS-AISH Publication (248) 451-458
End-member mixing analysis has been used to determine the hydrological structure for basin hydrochemical models at several catchments. Implicit in this use is the assumption that controlling end members have been identified, and that these end members represent distinct landscape locations. At the Panola Mountain Research Watershed, the choice of...
History and status of introduced mammals and impacts to breeding seabirds on the California channel and Northwestern Baja California Islands
G.J. McChesney, B.R. Tershy
1998, Waterbirds (21) 335-347
The California Channel Islands, U.S.A., and Northwestern Baja California Islands, Mexico, host important breeding populations of several seabird species, including the endemic Black-vented Shearwater (Puffinus opisthomelas) and Xantus' Murrelet (Synthliboramphus hypoleucus). Mammals introduced to nearly all of the islands beginning in the late 1800s to early 1900s include: cats (Felis...
Soil carbon stocks and their rates of accumulation and loss in a boreal forest landscape
G. Rapalee, S.E. Trumbore, E.A. Davidson, Jennifer W. Harden, H. Veldhuis
1998, Global Biogeochemical Cycles (12) 687-701
Boreal forests and wetlands are thought to be significant carbon sinks, and they could become net C sources as the Earth warms. Most of the C of boreal forest ecosystems is stored in the moss layer and in the soil. The objective of this study was to estimate soil C...
Application of the surface complexation concept to complex mineral assemblages
J.A. Davis, J.A. Coston, D.B. Kent, C. C. Fuller
1998, Environmental Science & Technology (32) 2820-2828
Two types of modeling approaches are illustrated for describing inorganic contaminant adsorption in aqueous environments: (a) the component additivity approach and (b) the generalized composite approach. Each approach is applied to simulate Zn2+ adsorption by a well-characterized sediment collected from an aquifer at Cape Cod, MA. Zn2+ adsorption by the...
Correlation of 2,3,7,8-tetrachlorodibenzo-p-dioxin-induced apoptotic cell death in the embryonic vasculature with embryotoxicity
Susannah M. Cantrell, Jennifer Joy-Schlezinger, John J. Stegeman, Donald E. Tillitt, Mark D. Hannington
1998, Toxicology and Applied Pharmacology (148) 24-34
Vertebrate embryos are particularly sensitive to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Identification of tissues that are susceptible to the adverse effects of TCDD is requisite for understanding the embryo toxic effects of TCDD. The objective of the present study was to quantitate the temporal appearance of and dose dependence of apoptosis in TCDD-exposed...
DDE, mercury, and selenium in biota, sediments, and water of the Rio Grande - Rio Bravo Basin, 1965-95
M.A. Mora, S.E. Wainwright
1998, Book chapter, Reviews of environmental contamination and toxicology
No abstract available....
Assessment of smolt condition for travel time analysis. Project review 1987-1997
R. M. Schrock, J.W. Beeman, P.V. Haner, K.M. Hans, J.D. Hotchkiss, S.T. Sauter, S. P. VanderKooi, W.L. Gale, P.A. Petrusso, A.G. Maule
1998, Report
Abstract not available...
Chemical and biological characteristics of desert rock pools in intermittent streams of Capitol Reef National Park, Utah
Jill Baron, Toben LaFrancois, Boris C. Kondratieff
1998, Great Basin Naturalist (58) 250-264
Chemical variability and biological communities of rock pools found in small desert drainage basins of Capitol Reef National Park were characterized over 8 mon in 1994. Neither flooding, drying, nor the presence or absence of surrounding vegetated wetlands had a great effect on chemical composition, which was very dilute and...
Trace element trophic transfer in aquatic organisms: A critique of the kinetic model approach
J.R. Reinfelder, N.S. Fisher, S. N. Luoma, J.W. Nichols, W.-X. Wang
1998, Science of the Total Environment (213) 117-135
The bioaccumulation of trace elements in aquatic organisms can be described with a kinetic model that includes linear expressions for uptake and elimination from dissolved and dietary sources. Within this model, trace element trophic transfer is described by four parameters: the weight-specific ingestion rate (IR); the assimilation efficiency (AE); the...
A nowcast model for tides and tidal currents in San Francisco Bay, California
Ralph T. Cheng, Richard E. Smith
1998, Conference Paper
National Oceanographic and Atmospheric Administration (NOAA) installed Physical Oceanographic Real-Time System (PORTS) in San Francisco Bay, California to provide observations of tides, tidal currents, and meteorological conditions. PORTS data are used for optimizing vessel operations, increasing margin of safety for navigation, and guiding hazardous material spill prevention and response. Because...
KERNELHR: A program for estimating animal home ranges
D.E. Seaman, B. Griffith, R. A. Powell
1998, Wildlife Society Bulletin (26) 95-100
Kernel methods are state of the art for estimating animal home-range area and utilization distribution (UD). The KERNELHR program was developed to provide researchers and managers a tool to implement this extremely flexible set of methods with many variants. KERNELHR runs interactively or from the command line on any personal...
Flow and suspended particulate transport in a tidal bottom layer, south San Francisco Bay, California
R. T. Cheng, J. W. Gartner, D.A. Cacchione, G. B. Tate
1998, Conference Paper, Physics of estuaries and coastal seas: Proceedings of the 8th International Biennial Conference on Physics of Estuaries and Coastal Seas
Field investigations of the hydrodynamics and the resuspension and transport of particulate matter in a bottom boundary layer were carried out in South San Francisco Bay, California during March-April 1995. The GEOPROBE, an instrumented bottom tripod, and broad-band acousti Doppler current profilers were used in this investigation. The instrument assemblage...
Carbon cycling in terrestrial environments: Chapter 17
Yang Wang, Thomas G. Huntington, Laurie J. Osher, Leonard I Wassenaar, Susan E. Trumbore, Ronald Amundson, Jennifer W. Harden, Diane M. McKnight, Sherry L. Schiff, George R. Aiken, W. Berry Lyons, Ramon O. Aravena, Jill Baron
1998, Book chapter, Isotope tracers in catchment hydrology
This chapter reviews a number of applications of isotopic techniques for the investigation of carbon cycling processes. Carbon dioxide (C02) is an important greenhouse gas. Its concentration in the atmosphere has increased from an estimated 270 ppm at the beginning of the industrial revolution to ∼ 360 ppm at present....
Scientific foundation for the natural community conservation planning / coastal sage scrub program
P.A. Stine
1998, Book chapter, Bioregional Assessments.
No abstract available at this time...
Estimating maize production in Kenya using NDVI: Some statistical considerations
J.E. Lewis, James Rowland, A. Nadeau
1998, International Journal of Remote Sensing (19) 2609-2617
A regression model approach using a normalized difference vegetation index (NDVI) has the potential for estimating crop production in East Africa. However, before production estimation can become a reality, the underlying model assumptions and statistical nature of the sample data (NDVI and crop production) must be examined rigorously. Annual maize...
