The nature of the crust under Cayman Trough from gravity
Uri S. ten Brink, D.F. Coleman, William P. Dillon
2002, Marine and Petroleum Geology (19) 971-987
Considerable crustal thickness variations are inferred along Cayman Trough, a slow-spreading ocean basin in the Caribbean Sea, from modeling of the gravity field. The crust to a distance of 50 km from the spreading center is only 2–3 km thick in agreement with dredge and dive results. Crustal thickness increases to ∼5.5 km...
Unconventional shallow biogenic gas systems
G. W. Shurr, J.L. Ridgley
2002, American Association of Petroleum Geologists Bulletin (86) 1939-1969
Unconventional shallow biogenic gas falls into two distinct systems that have different attributes. Early-generation systems have blanketlike geometries, and gas generation begins soon after deposition of reservoir and source rocks. Late-generation systems have ringlike geometries, and long time intervals separate deposition of reservoir and source rocks from gas generation. For...
Influences of spatial and temporal variation on fish-habitat relationships defined by regression quantiles
J. B. Dunham, B.S. Cade, J.W. Terrell
2002, Transactions of the American Fisheries Society (131) 86-98
We used regression quantiles to model potentially limiting relationships between the standing crop of cutthroat trout Oncorhynchus clarki and measures of stream channel morphology. Regression quantile models indicated that variation in fish density was inversely related to the width:depth ratio of streams but not to stream width or depth alone....
Antimicrobial residues in animal waste and water resources proximal to large-scale swine and poultry feeding operations
E.R. Campagnolo, K.R. Johnson, A. Karpati, C.S. Rubin, D.W. Kolpin, M. T. Meyer, J. Emilio Esteban, R.W. Currier, K. Smith, K.M. Thu, M. McGeehin
2002, Science of the Total Environment (299) 89-95
Expansion and intensification of large-scale animal feeding operations (AFOs) in the United States has resulted in concern about environmental contamination and its potential public health impacts. The objective of this investigation was to obtain background data on a broad profile of antimicrobial residues in animal wastes and surface water and...
The National Biological Information Infrastructure as an E-Government tool
R. Sepic, K. Kase
2002, Government Information Quarterly (19) 407-424
Coordinated by the U.S. Geological Survey (USGS), the National Biological Information Infrastructure (NBII) is a Web-based system that provides access to data and information on the nation's biological resources. Although it was begun in 1993, predating any formal E-Government initiative, the NBII typifies the E-Government concepts outlined in the President's...
Spatial correlations of Diceroprocta apache and its host plants: Evidence for a negative impact from Tamarix invasion
A.R. Ellingson, D.C. Andersen
2002, Ecological Entomology (27) 16-24
1. The hypothesis that the habitat-scale spatial distribution of the Apache cicada Diceroprocta apache Davis is unaffected by the presence of the invasive exotic saltcedar Tamarix ramosissima was tested using data from 205 1-m2 quadrats placed within the flood-plain of the Bill Williams River, Arizona, U.S.A. Spatial dependencies within and...
Distribution of metals in water and bed sediment in a mineral-rich watershed, Montana, USA
Sonia A. Nagorski, Johnnie N Moore, David B. Smith
2002, Mine Water and the Environment (21) 121-136
We sampled the Blackfoot River (Montana) and its major tributaries from the headwaters of the basin to near its confluence with the Clark Fork River over the course of 5 days in August 1998. We measured streamflow, collected fine-grained (<63 μm) streambed sediment, and sampled the dissolved (operationally defined as...
Estradiol-induced gene expression in largemouth bass (Micropterus salmoides)
C.J. Bowman, K.J. Kroll, T.G. Gross, N. D. Denslow
2002, Molecular and Cellular Endocrinology (196) 67-77
Vitellogenin (Vtg) and estrogen receptor (ER) gene expression levels were measured in largemouth bass to evaluate the activation of the ER-mediated pathway by estradiol (E2). Single injections of E2 ranging from 0.0005 to 5 mg/kg up-regulated plasma Vtg in a dose-dependent manner. Vtg and ER mRNAs were measured using partial...
Nitrogen dynamics in an Alaskan salt marsh following spring use by geese
Amy B. Zacheis, Roger W. Ruess, Jerry W. Hupp
2002, Oecologia (130) 600-608
Lesser snow geese (Anser caerulescens caerulescens) and Canada geese (Branta canadensis) use several salt marshes in Cook Inlet, Alaska, as stopover areas for brief periods during spring migration. We investigated the effects of geese on nitrogen cycling processes in Susitna Flats, one of the marshes. We...
Structure and flow-induced variability of the subtidal salinity field in northern San Francisco Bay
Stephen G. Monismith, Wim Kimmerer, Jon R. Burau, Mark T. Stacey
2002, Journal of Physical Oceanography (32) 3003-3019
The structure of the salinity field in northern San Francisco Bay and how it is affected by freshwater flow are discussed. Two datasets are examined: the first is 23 years of daily salinity data taken by the U.S. Bureau of Reclamation along the axis of northern San Francisco Bay; the...
Alkylcyclohexanes in environmental geochemistry
F. D. Hostettler, K.A. Kvenvolden
2002, Conference Paper, Environment Canada Arctic and Marine Oil Spill Program Technical Seminar (AMOP) Proceedings
Two case studies of oil spills that demonstrate the changing distribution patterns resulting from long-term anaerobic microbial degradation were presented. These spills were the 1979 crude-oil spill in Bemidji, MN, and a chronic diesel-fuel spillage from 1953-1991 at Mandan, ND. The alkylcyclohexanes in both spilled oil products were affected by...
Global petroleum resources: A view to the future
Thomas S. Ahlbrandt, P.J. McCabe
2002, Geotimes (47) 14-18
It is necessary to periodically reassess petroleum resources, not only because new data become available and better geologic models are developed; but also because many non-geologic factors determine which part of the crustal abundance of petroleum will be economic and acceptable over the foreseeable future. In 2000, the U.S. Geological...
Scaling roads and wildlife: The Cinderella principle
J.A. Bissonette
2002, Conference Paper, Zeitschrift fur Jagdwissenschaft
It is clear that a reduction in both direct and indirect effects of roads and road networks must be the goal of management agencies. However, increased permeability of roaded landscapes can only be achieved by up-front planning and subsequent mitigative actions. The key is to understand that roads must be...
Evidence for two surface ruptures in the past 500 years on the San Andreas fault at Frazier Mountain, California
S. C. Lindvall, T. K. Rockwell, T. E. Dawson, J. G. Helms, K. W. Bowman
2002, Bulletin of the Seismological Society of America (92) 2689-2703
We conducted paleoseismic studies in a closed depression along the San Andreas fault on the north flank of Frazier Mountain near Frazier Park, California. We recognized two earthquake ruptures in our trench exposure and interpreted the most recent rupture, event 1, to represent the historical 1857 earthquake. We also exposed...
Considerations for sampling inorganic constituents in ground water using diffusion samplers
D.A. Vroblesky, M.D. Petkewich, T.R. Campbell
Gavaskar A.R.Chen A.S.C., editor(s)
2002, Conference Paper, Proceedings of the Third International Conference on Remediation of Chlorinated and Recalcitrant Compounds
Data indicate that nylon-screen and dialysis diffusion samplers are capable of obtaining concentrations of inorganic solutes in ground water from wells that closely correspond to concentrations obtained by low-flow sampling. Conservative solutes, such as chloride, can be sampled by filling the diffusion samplers with oxygenated water. The samplers should be...
Chemical attributes of some clouds amid a forest ecosystem's trees
Thomas P. DeFelice
2002, Atmospheric Research (65) 35-50
Simultaneous physical and chemical characteristics of clouds amid and above the trees of a montane forest, located about 3.3 km southwest of Mt. Mitchell, NC, were collected between 13 and 22 June 1993. This paper summarizes the chemical characteristics of the cloud droplets amid the trees. The ionic composition and...
Determining mineral weathering rates based on solid and solute weathering gradients and velocities: Application to biotite weathering in saprolites
A. F. White
2002, Chemical Geology (190) 69-89
Chemical weathering gradients are defined by the changes in the measured elemental concentrations in solids and pore waters with depth in soils and regoliths. An increase in the mineral weathering rate increases the change in these concentrations with depth while increases in the weathering velocity decrease the change. The solid-state...
Nestling sex ratio in the Southwestern Willow Flycatcher
E. H. Paxton, M. K. Sogge, T.D. McCarthey, P. Keim
2002, Condor (104) 877-881
Using molecular-genetic techniques, we determined the gender of 202 Southwestern Willow Flycatcher (Empidonax traillii extimus) nestlings from 95 nests sampled over a five-year period. Overall nestling sex ratio did not vary significantly from 50:50 among years, by clutch order, or by mating strategy (monogamous vs. polygamous pairings). However, we did...
Fate and effects of the triazinone herbicide metribuzin in experimental pond mesocosms
J.F. Fairchild, L.C. Sappington
2002, Archives of Environmental Contamination and Toxicology (43) 198-202
Metribuzin is a triazinone herbicide that is widely used for the control of grasses and broad-leaved weeds in soybeans, sugarcane, and numerous other crops. Metribuzin is highly toxic to freshwater macrophytes and algae under laboratory conditions (median plant EC50 = 31 ??g/L; n = 11 species) but has not been...
The flora of Oktibbeha County, Mississippi
A. Leidolf, S. McDaniel, T. Nuttle
2002, SIDA, Contributions to Botany (20) 691-765
We surveyed the flora of Oktibbeha County, Mississippi, U.S.A., from February 1994 to 1996. Occupying 118 square kilometers in east-central Mississippi, Oktibbeha County lies among 3 physiographic regions that include, from west to east, Interior Flatwoods, Pontotoc Ridge, and Black Prairie. Accordingly, the county harbors a diverse flora. Based on...
Evidence for large-scale reworking of Campanian sediments into the Upper Maastrichtian Peedee formation at Burches Ferry, South Carolina
Self-Trail J.M., R. A. Christopher, D.C. Prowell
2002, Southeastern Geology (41) 145-158
A 44-ft-deep corehole (FLO-311) was drilled at Burches Ferry, Florence County, S.C., in order to document the lithologic and paleontologic characteristics of the boundary between the upper Campanian Donoho Creek Formation and the upper Maastrichtian Peedee Formation. Palynomorph and calcareous nannofossil data provide detailed age control for these sediments. Examination...
Performance of a satellite-linked GPS on Pacific walruses (Odobenus rosmarus divergens)
Chadwick V. Jay, Gerald W. Garner
2002, Polar Biology (25) 235-237
We evaluated the utility of a satellite-linked GPS in obtaining location data from Pacific walruses (Odobenus rosmarus divergens). A unit was attached to one of the tusks of each of three adult male walruses in Bristol Bay, Alaska. The units were designed to relay GPS positions through the Argos Data...
Patterns of food abundance for breeding waterbirds in the San Luis Valley of Colorado
James H. Gammonley, Murray K. Laubhan
2002, Wetlands (22) 499-508
We measured the amount and distribution of macroinvertebrates and seeds in four wetland habitats (short emergent, seasonal open water, semipermanent/permanent open water, and saltgrass [Distichlis spicata]) used by breeding ducks and shorebirds at a wetland complex in the San Luis Valley, Colorado, USA. Density of macroinvertebrates did not differ among...
National Wildlife Health Center's Quarterly Mortality Report
K. A. Converse, R. Sohn, G. McLaughlin, C. Lemanksi
2002, Supplement to the Journal of Wildlife Diseases (38)
A step increase in streamflow in the conterminous United States
G.J. McCabe, D.M. Wolock
2002, Geophysical Research Letters (29) 38-1-38-4
Annual minimum, median, and maximum daily streamflow for 400 sites in the conterminous United States (U.S.), measured during 1941-1999, were examined to identify the temporal and spatial character of changes in streamflow statistics. Results indicate a noticeable increase in annual minimum and median daily streamflow around 1970, and a less...
