Spatial and overwinter changes in clam populations of San Pablo Bay, a semiarid estuary with highly variable freshwater inflow
V.K. Poulton, J.R. Lovvorn, John Y. Takekawa
2004, Estuarine, Coastal and Shelf Science (59) 459-473
In many estuaries worldwide, climate trends together with human diversion of fresh water have dramatically impacted the benthos. Such impacts have sometimes been complicated by exotic species, whose invasion and persistence can be mediated by wide variations in freshwater inflow. Monitoring such changes usually involves periodic samples at a few...
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...
Geographic variation in patterns of nestedness among local stream fish assemblages in Virginia
R.R. Cook, P. L. Angermeier, D.S. Finn, N.L. Poff, K.L. Krueger
2004, Oecologia (140) 639-649
Nestedness of faunal assemblages is a multiscale phenomenon, potentially influenced by a variety of factors. Prior small-scale studies have found freshwater fish species assemblages to be nested along stream courses as a result of either selective colonization or extinction. However, within-stream gradients in temperature and other factors are correlated with...
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...
Variation in responses to spawning Pacific salmon among three south-eastern Alaska streams
D. T. Chaloner, G. A. Lamberti, R.W. Merritt, N.L. Mitchell, P.H. Ostrom, M.S. Wipfli
2004, Freshwater Biology (49) 587-599
1. Pacific salmon are thought to stimulate the productivity of the fresh waters in which they spawn by fertilising them with marine-derived nutrients (MDN). We compared the influence of salmon spawners on surface streamwater chemistry and benthic biota among three southeastern Alaska streams. Within each stream, reaches up- and downstream...
Host social behavior and parasitic infection: A multifactorial approach
V.O. Ezenwa
2004, Behavioral Ecology (15) 446-454
I examined associations between several components of host social organization, including group size and gregariousness, group stability, territoriality and social class, and gastrointestinal parasite load in African bovids. At an intraspecific level, group size was positively correlated with parasite prevalence, but only when the parasite was relatively host specific and...
Contaminants in molting long-tailed ducks and nesting common eiders in the Beaufort Sea
J. C. Franson, Tuula E. Hollmén, Paul L. Flint, J.B. Grand, Richard B. Lanctot
2004, Marine Pollution Bulletin (48) 504-513
In 2000, we collected blood from long-tailed ducks (Clangula hyemalis) and blood and eggs from common eiders (Somateria mollissima) at near-shore islands in the vicinity of Prudhoe Bay, Alaska, and at a reference area east of Prudhoe Bay. Blood was analyzed for trace elements and egg contents were analyzed for...
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...
Asymmetrical effects of introduced Bullfrogs (Rana catesbeiana) on native Ranid Frogs in Oregon
C.A. Pearl, M.J. Adams, R.B. Bury, B. McCreary
2004, Copeia 11-20
Introduced American Bullfrogs (Rana catesbeiana) have become widely established in the Pacific Northwest over the last century and are thought to be an important predator of native amphibians throughout the western United States. The Northern Red-Legged Frog (Rana aurora aurora) and Oregon Spotted Frog (Rana pretiosa) historically coexisted in portions...
Diets and foraging behavior of northern Spotted Owls in Oregon
E.D. Forsman, R.G. Anthony, E. Charles Meslow, C.J. Zabel
2004, Journal of Raptor Research (38) 214-230
We describe local, regional, and annual variation in diets of northern Spotted Owls (Strix occidentalis caurina) in Oregon based on 24 497 prey collected at 1118 owl territories in 1970-2003. The sample included 91.5% mammals, 4.3% birds, 4.1% insects, and 0.1% other prey. The diet included ???131 species, including 49...
Discovery of Sphaeroma terebrans, a wood-boring isopod, in the red mangrove, Rhizophora mangle, habitat of northern Florida Bay
R. A. Brooks
2004, Ambio (33) 171-173
No abstract available....
Effects of lowhead dams on riffle-dwelling fishes and macroinvertebrates in a Midwestern river
J.S. Tiemann, D.P. Gillette, M. L. Wildhaber, D.R. Edds
2004, Transactions of the American Fisheries Society (133) 705-717
Many studies have assessed the effects of large dams on fishes and macroinvertebrates, but few have examined the effects of lowhead dams. We sampled fishes, macroinvertebrates, habitat, and physicochemistry monthly from November 2000 to October 2001 at eight gravel bar sites centered around two lowhead dams on the Neosho River,...
A definitive calibration record for the Landsat-5 thematic mapper anchored to the Landsat-7 radiometric scale
P.M. Teillet, D. L. Helder, T.A. Ruggles, R. Landry, F.J. Ahern, N.J. Higgs, J. Barsi, G. Chander, B. L. Markham, J. L. Barker, K. J. Thome, J. R. Schott, Frank Don Palluconi
2004, Canadian Journal of Remote Sensing (30) 631-643
A coordinated effort on the part of several agencies has led to the specification of a definitive radiometric calibration record for the Landsat-5 thematic mapper (TM) for its lifetime since launch in 1984. The time-dependent calibration record for Landsat-5 TM has been placed on the same radiometric scale as the...
Effects of predation risk on habitat selection by water column fish, benthic fish and crayfish in stream pools
D.D. Magoulick
2004, Hydrobiologia (527) 209-221
Predation risk can affect habitat selection by water column stream fish and crayfish, but little is known regarding effects of predation risk on habitat selection by benthic fish or assemblages of fish and crayfish. I used comparative studies and manipulative field experiments to determine whether, (1) habitat selection by stream...
Stratigraphy and sedimentology of the Upper Cretaceous (Campanian) Anacacho Limestone, Texas, USA
C.S. Swezey, E.C. Sullivan
2004, Cretaceous Research (25) 473-497
The Upper Cretaceous Anacacho Limestone is exposed in outcrops between the cities of San Antonio and Del Rio, Texas. A detailed study of four outcrops (Blanco Creek section, Sabinal River section, Seco Creek section, Hondo Creek section) shows that the Anacacho Limestone rests on the Upson Clay (which contains fauna...
Export production in the subarctic North Pacific over the last 800 kyrs: No evidence for iron fertilization?
S.S. Kienast, I.L. Hendy, John Crusius, Thomas F. Pedersen, S.E. Calvert
2004, Journal of Oceanography (60) 189-203
The subarctic North Pacific is a high nitrate-low chlorophyll (HNLC) region, where phytoplankton growth rates, especially those of diatoms, are enhanced when micronutrient Fe is added. Accordingly, it has been suggested that glacial Fe-laden dust might have increased primary production in this region. This paper reviews published palaeoceanographic records of...
Magmatic precursors to the 18 May 1980 eruption of Mount St. Helens, USA
K. V. Cashman, R. Hoblitt
2004, Geology (32) 141-144
Perhaps the most difficult task facing volcanologists today is that of distinguishing between low-level volcanic restlessness and activity that presages a full-scale eruption. We illustrate these difficulties by reexamining the sequence of events that led to the 18 May 1980 eruption of Mount St. Helens, activity that is often presented...
Effects of trichloroethylene and perchloroethylene on wild rodents at Edwards Air Force Base, California, USA
Sarah E. Spring, A. Keith Miles, Michael J. Anderson
2004, Environmental Toxicology and Chemistry (23) 2162-2169
Effects of inhalation of volatilized trichloroethylene (TCE) or perchloroethylene (PCE) were assessed based on the health and population size of wild, burrowing mammals at Edwards Air Force Base (CA, USA). Organic soil-vapor concentrations were measured at three sites with aquifer contamination of TCE or PCE of 5.5 to 77 mg/L...
Effects of model sensitivity and nonlinearity on nonlinear regression of ground water flow
R. M. Yager
2004, Ground Water (42) 390-400
Nonlinear regression is increasingly applied to the calibration of hydrologic models through the use of perturbation methods to compute the Jacobian or sensitivity matrix required by the Gauss-Newton optimization method. Sensitivities obtained by perturbation methods can be less accurate than those obtained by direct differentiation, however, and concern has arisen...
Methods for estimating adsorbed uranium(VI) and distribution coefficients of contaminated sediments
M. Kohler, G.P. Curtis, D.E. Meece, J.A. Davis
2004, Environmental Science & Technology (38) 240-247
Assessing the quantity of U(VI) that participates in sorption/desorption processes in a contaminated aquifer is an important task when investigating U migration behavior. U-contaminated aquifer sediments were obtained from 16 different locations at a former U mill tailings site at Naturita, CO (U.S.A.) and were extracted with an artificial groundwater,...
Fast ground-water mixing and basal recharge in an unconfined, alluvial aquifer, Konza LTER Site, Northeastern Kansas
G.L. Macpherson, M. Sophocleous
2004, Journal of Hydrology (286) 271-299
Ground-water chemistry and water levels at three levels in a well nest were monitored biweekly for two and a half years in a shallow unconfined floodplain aquifer in order to study the dynamics of such shallow aquifers. The aquifer, in northeastern Kansas, consists of high porosity, low hydraulic conductivity fine-grained...
Field and laboratory arsenic speciation methods and their application to natural-water analysis
A.J. Bednar, J.R. Garbarino, M.R. Burkhardt, J. F. Ranville, T.R. Wildeman
2004, Water Research (38) 355-364
The toxic and carcinogenic properties of inorganic and organic arsenic species make their determination in natural water vitally important. Determination of individual inorganic and organic arsenic species is critical because the toxicology, mobility, and adsorptivity vary substantially. Several methods for the speciation of arsenic in groundwater, surface-water, and acid mine...
Remote sensing and the optical properties of the narrow cylindrical leaves of Juncus roemerianus
Elijah W. Ramsey III, A. Rangoonwala
2004, IEEE Transactions on Geoscience and Remote Sensing (42) 1064-1075
To develop a more complete foundation for remote sensing of the marsh grass Juncus roemerianus, we measured the optical properties of its cylindrical leaves at sites of different canopy height, biomass composition and amount, and connectivity to ocean flushing. To measure the leaf optical properties, we adapted a technique used...
Geochemical discrimination of five pleistocene lava-dam outburst-flood deposits, western Grand Canyon, Arizona
C.R. Fenton, R.J. Poreda, B.P. Nash, R. H. Webb, T.E. Cerling
2004, Journal of Geology (112) 91-110
Pleistocene basaltic lava dams and outburst‐flood deposits in the western Grand Canyon, Arizona, have been correlated by means of cosmogenic 3He (3Hec) ages and concentrations of SiO2, Na2O, K2O, and rare earth elements. These data indicate that basalt clasts and vitroclasts in a given outburst‐flood deposit came from a common source,...
Magmatic intrusion west of Three Sisters, central Oregon, USA: The perspective from spring geochemistry
William C. Evans, M.C. van Soest, Robert H. Mariner, S. Hurwitz, S. E. Ingebritsen, C.W. Wicks Jr., M.E. Schmidt
2004, Geology (32) 69-72
A geochemical investigation of springs near Three Sisters volcanoes was conducted in response to the detection of crustal uplift west of the peaks. Dilute, low-temperature springs near the center of uplift show 3He/4He ratios ≥7RA (RA is the ratio in air), and transport in total ∼16...
