Timing of seed dispersal generates a bimodal seed bank depth distribution
J. L. Espinar, K. Thompson, L. V. Garcia
2005, American Journal of Botany (92) 1759-1763
The density of soil seed banks is normally highest at the soil surface and declines monotonically with depth. Sometimes, for a variety of reasons, peak density occurs below the surface but, except in severely disturbed soils, it is generally true that deeper seeds are older. In seasonally dry habitats that...
Evaluation of ecological risk to populations of a threatened plant from an invasive biocontrol insect
S. M. Louda, T. A. Rand, A. E. Arnett, A. S. McClay, A. K. McEachern
2005, Ecological Applications (15) 234-249
Controversy exists over estimation of ecological risk in biological control. At present, the risk to the rare, federally listed Pitcher's thistle (Cirsium pitcheri) in North America from Rhinocyllus conicus, a biological control weevil now feeding on many native thistles, is unknown. We hypothesized that quantification of host specificity and potential...
Basal tissue structure in the earliest euconodonts: Testing hypotheses of developmental plasticity in euconodont phylogeny
X.-P. Dong, P.C.J. Donoghue, J.E. Repetski
2005, Palaeontology (48) 411-421
The hypothesis that conodonts are vertebrates rests solely on evidence of soft tissue anatomy. This has been corroborated by microstructural, topological and developmental evidence of homology between conodont and vertebrate hard tissues. However, these conclusions have been reached on the basis of evidence from highly derived euconodont taxa and the...
Eastern rim of the Chesapeake Bay impact crater: Morphology, stratigraphy, and structure
C. W. Poag
2005, Special Paper of the Geological Society of America 117-130
This study reexamines seven reprocessed (increased vertical exaggeration) seismic reflection profiles that cross the eastern rim of the Chesapeake Bay impact crater. The eastern rim is expressed as an arcuate ridge that borders the crater in a fashion typical of the "raised" rim documented in many well preserved complex impact...
Petrophysics of Lower Silurian sandstones and integration with the tectonic-stratigraphic framework, Appalachian basin, United States
J.W. Castle, A.P. Byrnes
2005, American Association of Petroleum Geologists Bulletin (89) 41-60
Petrophysical properties were determined for six facies in Lower Silurian sandstones of the Appalachian basin: fluvial, estuarine, upper shoreface, lower shoreface, tidal channel, and tidal flat. Fluvial sandstones have the highest permeability for a given porosity and exhibit a wide range of porosity (2-18%) and permeability (0.002-450 md). With a...
Total mercury concentrations in fillets of bluegill, redear sunfish, largemouth bass, and other fishes from Lake Natoma, Sacramento County, California
M. K. Saiki, B.A. Martin, T.W. May, Charles N. Alpers
2005, California Fish and Game (91) 193-206
This study was conducted during September-October 2002 to verify preliminary findings of elevated total mercury concentrations in skinless fillets of sportfishes inhabiting Lake Natoma. Although we measured total mercury concentrations, most mercury in fish flesh occurs in the methylated form. In August 2000, other investigators collected a small number of...
Development of a bioenergetics model for humpback chub and evaluation of water temperature changes in the Grand Canyon, Colorado River
J.H. Petersen, C.P. Paukert
2005, Transactions of the American Fisheries Society (134) 960-974
The construction of Glen Canyon Dam above the Grand Canyon (Arizona) has reduced the water temperature in the Colorado River and altered the growth rate and feeding patterns of the federally endangered humpback chub Gila cypha. A bioenergetics model for humpback chub was developed and used to examine how warmer...
Do wintering Harlequin Ducks forage nocturnally at high latitudes?
Daniel Rizzolo, Daniel Esler, Daniel D. Roby, Robert L. Jarvis
2005, Condor (107) 173-177
We monitored radio-tagged Harlequin Ducks (Histrionicus histrionicus) to determine whether nocturnal feeding was part of their foraging strategy during winter in south-central Alaska. Despite attributes of our study site (low ambient temperatures, harsh weather, short day length) and study species (small body size, high daytime foraging rates) that would be...
Transient population dynamics: Relations to life history and initial population state
D. N. Koons, J.B. Grand, B. Zinner, R.F. Rockwell
2005, Ecological Modelling (185) 283-297
Most environments are variable and disturbances (e.g., hurricanes, fires) can lead to substantial changes in a population's state (i.e., age, stage, or size distribution). In these situations, the long-term (i.e., asymptotic) measure of population growth rate (??1) may inaccurately represent population growth in the short-term. Thus, we calculated the short-term...
Overview of radiometric ages in three allochthonous belts of northern Venezuela: Old ones, new ones, and their impact on regional geology
V.B. Sisson, H.G. Ave Lallemant, M. Ostos, A.E. Blythe, Lawrence W. Snee, Peter Copeland, J.E. Wright, R.A. Donelick, L.R. Guth
2005, Special Paper of the Geological Society of America (394) 91-117
The margin of northern Venezuela is a complex zone representing the orogenic events from basement formation to subsequent subduction and exhumation during transpressional collision. This boundary zone has six east-west–trending belts that each record a different segment of its development. This geologic complexity requires radiometric ages to unravel, and we...
Cortisol receptor blockade and seawater adaptation in the euryhaline teleost Fundulus heteroclitus
W.S. Marshall, R.R.F. Cozzi, Ryan M. Pelis, S. D. McCormick
2005, Journal of Experimental Zoology Part A: Comparative Experimental Biology (303) 132-142
To examine the role of cortisol in seawater osmoregulation in a euryhaline teleost, adult killifish were acclimated to brackish water (10???) and RU486 or vehicle was administered orally in peanut oil daily for five days at low (40 mg.kg-1) or high dose (200 mg.kg-1). Fish were transferred to 1.5 x...
Comment on "How can seismic hazard around the New Madrid seismic zone be similar to that in California?" by Arthur Frankel
Z. Wang, B. Shi, J. D. Kiefer
2005, Seismological Research Letters (76) 466-471
A recent paper in the September/October 2004 issue of Seismological Research Letters, “How Can Seismic Hazard around the New Madrid Seismic Zone Be Similar to That in California?”, by Arthur Frankel, concludes “I have demonstrated how probabilistic seismic hazard for New Madrid can be greater than that at San Francisco at low...
Subsidence hazards due to evaporite dissolution in the United States
Kenneth S. Johnson
2005, Environmental Geology (48) 395-409
Evaporites, including gypsum (or anhydrite) and salt, are the most soluble of common rocks; they are dissolved readily to form the same type of karst features that typically are found in limestones and dolomites, and their dissolution can locally result in major subsidence structures. The four basic requirements for evaporite...
Burrowing mayflies as indicators of ecosystem health: Status of populations in western Lake Erie, Saginaw Bay and Green Bay
T.A. Edsall, M.T. Bur, O. T. Gorman, J.S. Schaeffer
2005, Aquatic Ecosystem Health & Management (8) 107-116
The U.S. Environmental Protection Agency and Environment Canada are supporting the development of indicators of ecosystem health that can be used to report on progress in restoring and maintaining the Great Lakes ecosystem, as called for in the Great Lakes Water Quality Agreement between the United States and Canada. One...
Development of ground-motion prediction equations relevant to shallow-mining-induced seismicity in the Trial Mountain area, Emery County, Utah
Art McGarr, Joe B. Fletcher
2005, Bulletin of the Seismological Society of America (95) 31-47
To provide a basis for assessing the seismic hazard to the Joes Valley Dam due to future coal mining in the nearby Cottonwood Tract, central Utah, we developed ground-motion prediction relations using data recorded by a seismic network, established and operated by the University of Utah Seismograph Stations. The network...
"Sour gas" hydrothermal jarosite: Ancient to modern acid-sulfate mineralization in the southern Rio Grande Rift
V.W. Lueth, R. O. Rye, L. Peters
2005, Chemical Geology (215) 339-360
As many as 29 mining districts along the Rio Grande Rift in southern New Mexico contain Rio Grande Rift-type (RGR) deposits consisting of fluorite-barite??sulfide-jarosite, and additional RGR deposits occur to the south in the Basin and Range province near Chihuahua, Mexico. Jarosite occurs in many of these deposits as a...
Manatee occurrence in the northern Gulf of Mexico, west of Florida
D. Fertl, A. J. Schiro, G. T. Regan, Cathy A. Beck, N. Adimey, L. Price-May, A. Amos, Graham A.J. Worthy, R. Crossland
2005, Gulf and Caribbean Research (17) 69-94
Reports of West Indian manatees (Trichechus manatus) in the US Gulf of Mexico west of Florida have increased during the last decade. We reviewed all available manatee sighting, capture, and carcass records (n = 377) from Alabama, Louisiana, Mississippi, and Texas since the early 1900s; only 40 of these were...
Effects of biotic and abiotic factors on the distribution of trout and salmon along a longitudinal stream gradient
Hoz Franco De La Franco, E. A., P. Budy
2005, Environmental Biology of Fishes (72) 379-391
We examined the influence of biotic and abiotic factors on the distribution, abundance, and condition of salmonid fishes along a stream gradient. We observed a longitudinal change in fish distribution with native cutthroat trout, Oncorhynchus clarki utah, and introduced brown trout, Salmo trutta, demonstrating a distinct pattern of allopatry. Cutthroat...
Sheet flow and suspended sediment due to wave groups in a large wave flume
C. M. Dohmen-Janssen, D.M. Hanes
2005, Continental Shelf Research (25) 333-347
A series of sand bed experiments was carried out in the Large Wave Flume in Hannover, Germany as a component of the SISTEX99 experiment. The experiments focussed on the dynamic sediment response due to wave group forcing over a flat sand bed in order to improve understanding of cross-shore sediment...
Evidence for a global seismic-moment release sequence
C. G. Bufe, D. M. Perkins
2005, Bulletin of the Seismological Society of America (95) 833-843
Temporal clustering of the larger earthquakes (foreshock-mainshock-aftershock) followed by relative quiescence (stress shadow) are characteristic of seismic cycles along plate boundaries. A global seismic-moment release history, based on a little more than 100 years of instrumental earthquake data in an extended version of the catalog of Pacheco and Sykes (1992),...
Use of dissolved and vapor‐phase gases to investigate methanogenic degradation of petroleum hydrocarbon contamination in the subsurface
Richard T. Amos, K. Ulrich Mayer, Barbara A. Bekins, Geoffrey N. Delin, Randi L. Williams
2005, Water Resources Research (41)
At many sites contaminated with petroleum hydrocarbons, methanogenesis is a significant degradation pathway. Techniques to estimate CH4 production, consumption, and transport processes are needed to understand the geochemical system, provide a complete carbon mass balance, and quantify the hydrocarbon degradation rate. Dissolved and vapor‐phase gas data collected at a petroleum hydrocarbon...
A method for the use of landscape metrics in freshwater research and management
F.R. Kearns, N.M. Kelly, J.L. Carter, V.H. Resh
2005, Landscape Ecology (20) 113-125
Freshwater research and management efforts could be greatly enhanced by a better understanding of the relationship between landscape-scale factors and water quality indicators. This is particularly true in urban areas, where land transformation impacts stream systems at a variety of scales. Despite advances in landscape quantification methods, several studies...
Clustered streamlined forms in Athabasca Valles, Mars: Evidence for sediment deposition during floodwater ponding
D. Burr
2005, Geomorphology (69) 242-252
A unique clustering of layered streamlined forms in Athabasca Valles is hypothesized to reflect a significant hydraulic event. The forms, interpreted as sedimentary, are attributed to extensive sediment deposition during ponding and then streamlining of this sediment behind flow obstacles during ponded water outflow. These streamlined forms are analogous to...
Catastrophic meltwater discharge down the Hudson Valley: A potential trigger for the Intra-Allerød cold period
Jeffrey P. Donnelly, Neal W. Driscoll, Elazar Uchupi, Loyd D. Keigwin, William C. Schwab, E. Robert Thieler, Stephen A. Swift
2005, Geology (33) 89-92
Glacial freshwater discharge to the Atlantic Ocean during deglaciation may have inhibited oceanic thermohaline circulation, and is often postulated to have driven climatic fluctuations. Yet attributing meltwater-discharge events to particular climate oscillations is problematic, because the location, timing, and amount of meltwater discharge are often poorly constrained. We present evidence...
Movements of walruses radio-tagged in Bristol Bay, Alaska
Chadwick V. Jay, Susan Hills
2005, Arctic (58) 192-202
Satellite radio-location data from 57 adult male Pacific walruses (Odobenus rosmarus divergens) were used to estimate haul-out fidelity, broadly describe seasonal foraging distributions, and determine the approximate timing of autumn migration from Bristol Bay, Alaska. Data were collected intermittently during 1987–91 and 1995–2000, primarily during the period from May to...
