Dietary biomagnification of organochlorine contaminants in Alaskan polar bears
T.W. Bentzen, Erich H. Follmann, Steven C. Amstrup, G.S. York, M. J. Wooller, D.C.G. Muir, T. M. O'Hara
2008, Canadian Journal of Zoology (86) 177-191
Concentrations of organochlorine contaminants in the adipose tissue of polar bears (Ursus maritimus Phipps, 1774) vary throughout the Arctic. The range in concentrations has not been explained fully by bear age, sex, condition, location, or reproductive status. Dietary pathways expose polar bears to a variety of contaminant profiles and concentrations....
Simulation of Na D emission near Europa during eclipse
T.A. Cassidy, R.E. Johnson, P.E. Geissler, F. Leblanc
2008, Journal of Geophysical Research E: Planets (113)
The Cassini imaging science subsystem observed Europa in eclipse during Cassini's Jupiter flyby. The disk-resolved observations revealed a spatially nonuniform emission in the wavelength range of 200-1050 nm (clear filters). By building on observations and simulations of Europa's Na atmosphere and torus we find that electron-excited Na in Europa's tenuous...
Geomorphic evidence for former lobate debris aprons at low latitudes on Mars: Indicators of the Martian paleoclimate
E. Hauber, S. Van Gasselt, M. G. Chapman, G. Neukum
2008, Journal of Geophysical Research E: Planets (113)
Circumferential depressions enclosing mesas and plateaus in the northern Kasei Valles and in the Tartarus Colles regions of Mars are interpreted as indicators of the former extent of lobate debris aprons, thought to be mixtures of ice and elastic particles. These former lobate debris aprons existed about 1 Ga ago...
In situ estimation of the effective chemical diffusion coefficient of a rock matrix in a fractured aquifer
R.A. Gebrekristos, A.M. Shapiro, B.H. Usher
2008, Hydrogeology Journal (16) 629-639
An in situ method of estimating the effective diffusion coefficient for a chemical constituent that diffuses into the primary porosity of a rock is developed by abruptly changing the concentration of the dissolved constituent in a borehole in contact with the rock matrix and monitoring the time-varying concentration. The...
Transport and distribution of trace elements and other selected inorganic constituents by suspended particulates in the Salton Sea Basin, California, 2001
L.A. LeBlanc, R. A. Schroeder
2008, Hydrobiologia (604) 123-135
In order to examine the transport of contaminants associated with river-derived suspended particles in the Salton Sea, California, large volume water samples were collected in transects established along the three major rivers emptying into the Salton Sea in fall 2001. Rivers in this area carry significant aqueous and particulate contaminant...
Modeling unobserved sources of heterogeneity in animal abundance using a Dirichlet process prior
R.M. Dorazio, B. Mukherjee, L. Zhang, M. Ghosh, H.L. Jelks, F. Jordan
2008, Biometrics (64) 635-644
In surveys of natural populations of animals, a sampling protocol is often spatially replicated to collect a representative sample of the population. In these surveys, differences in abundance of animals among sample locations may induce spatial heterogeneity in the counts associated with a particular sampling protocol. For some species, the...
Processes of coastal bluff erosion in weakly lithified sands, Pacifica, California, USA
B.D. Collins, N. Sitar
2008, Geomorphology (97) 483-501
Coastal bluff erosion and landsliding are currently the major geomorphic processes sculpting much of the marine terrace dominated coastline of northern California. In this study, we identify the spatial and temporal processes responsible for erosion and landsliding in an area of weakly lithified sand coastal bluffs located south of San...
Lead sequestration and species redistribution during soil organic matter decomposition
A.W. Schroth, B.C. Bostick, J.M. Kaste, A. J. Friedland
2008, Environmental Science & Technology (42) 3627-3633
The turnover of soil organic matter (SOM) maintains a dynamic chemical environment in the forest floor that can impact metal speciation on relatively short timescales. Here we measure the speciation of Pb in controlled and natural organic (O) soil horizons to quantify changes in metal partitioning during SOM decomposition in...
Using HEM surveys to evaluate disposal of by-product water from CBNG development in the Powder River Basin, Wyoming
B.A. Lipinski, J.I. Sams, B. D. Smith, W. Harbert
2008, Geophysics (73)
Production of methane from thick, extensive coal beds in the Powder River Basin of Wyoming has created water management issues. Since development began in 1997, more than 650 billion liters of water have been produced from approximately 22,000 wells. Infiltration impoundments are used widely to dispose of by-product water from...
Limited occurrence of denitrification in four shallow aquifers in agricultural areas of the United States
C.T. Green, L.J. Puckett, J.K. Böhlke, B.A. Bekins, S.P. Phillips, L. J. Kauffman, J. M. Denver, H.M. Johnson
2008, Journal of Environmental Quality (37) 994-1009
The ability of natural attenuation to mitigate agricultural nitrate contamination in recharging aquifers was investigated in four important agricultural settings in the United States. The study used laboratory analyses, field measurements, and flow and transport modeling for monitoring well transects (0.5 to 2.5 km in length) in the San Joaquin...
Composition and quality of coals in the Huaibei Coalfield, Anhui, China
Lingyun Zheng, Gaisheng Liu, L. Wang, C. L. Chou
2008, Journal of Geochemical Exploration (97) 59-68
The Huaibei Coalfield, Anhui Province, China, is one of the largest coalfields in China. The coals of Permian age are used mainly for power generation. Coal compositions and 47 trace elements of the No. 10 Coal of the Shanxi Formation, the No. 7, 5, and 4 Coals of the Lower...
Climate controls on C3 vs. C4 productivity in North American grasslands from carbon isotope composition of soil organic matter
J.C. von Fischer, L.L. Tieszen, D. S. Schimel
2008, Global Change Biology (14) 1141-1155
We analyzed the ??13 C of soil organic matter (SOM) and fine roots from 55 native grassland sites widely distributed across the US and Canadian Great Plains to examine the relative production of C3 vs. C4 plants (hereafter %C4) at the continental scale. Our climate vs. %C4 results agreed well...
Biomarkers of mercury exposure at a mercury recycling facility in Ukraine
H.J. Gibb, K. Kozlov, J.P. Buckley, J. Centeno, V. Jurgenson, A. Kolker, K. Conko, E. Landa, B. Panov, Y. Panov, H. Xu
2008, Journal of Occupational and Environmental Hygiene (5) 483-489
This study evaluates biomarkers of occupational mercury exposure among workers at a mercury recycling operation in Gorlovka, Ukraine. The 29 study participants were divided into three occupational categories for analysis: (1) those who worked in the mercury recycling operation (Group A, n = 8), (2) those...
Terrace aggradation during the 1978 flood on Powder River, Montana, USA
J. A. Moody, R.H. Meade
2008, Geomorphology (99) 387-403
Flood processes no longer actively increase the planform area of terraces. Instead, lateral erosion decreases the area. However, infrequent extreme floods continue episodic aggradation of terraces surfaces. We quantify this type of evolution of terraces by an extreme flood in May 1978 on Powder River in southeastern Montana. Within an...
Impact effects and regional tectonic insights: Backstripping the Chesapeake Bay impact structure
T. Hayden, M. Kominz, David S. Powars, Lucy E. Edwards, K.G. Miller, J.V. Browning, A.A. Kulpecz
2008, Geology (36) 327-330
The Chesapeake Bay impact structure is a ca. 35.4 Ma crater located on the eastern seaboard of North America. Deposition returned to normal shortly after impact, resulting in a unique record of both impact-related and subsequent passive margin sedimentation. We use backstripping to show that the impact strongly affected sedimentation...
Soil nutrient-landscape relationships in a lowland tropical rainforest in Panama
F.K. Barthold, R.F. Stallard, H. Elsenbeer
2008, Forest Ecology and Management (255) 1135-1148
Soils play a crucial role in biogeochemical cycles as spatially distributed sources and sinks of nutrients. Any spatial patterns depend on soil forming processes, our understanding of which is still limited, especially in regards to tropical rainforests. The objective of our study was to investigate the effects of landscape properties,...
Middle UV to near-IR spectrum of electron-excited SO2
J.M. Ajello, A. Aguilar, R.S. Mangina, G.K. James, P. Geissler, L. Trafton
2008, Journal of Geophysical Research E: Planets (113)
We investigated the electron impact–induced fluorescence spectrum of SO2 to provide excitation cross sections for modeling Io's emission spectrum and analyzing Cassini Imaging Science Subsystem observations. The electron-excited middle-ultraviolet visible optical near-infrared (VOIR) emission spectrum of SO2 gas was generated in the laboratory and studied from 2000 to 11,000 Å at a...
Use of an annular chamber for testing thermal preference of westslope cutthroat trout and rainbow trout
T.E. McMahon, E.A. Bear, A.V. Zale
2008, Journal of Freshwater Ecology (23) 55-63
Remaining populations of westslope cutthroat trout (Oncorhynchus clarkii lewisi) in western North America are primarily confined to cold headwaters whereas nonnative rainbow trout (Oncorhynchus mykiss) predominate in warmer, lower elevation stream sections historically occupied by westslope cutthroat trout. We tested whether differing thermal preferences could account for the spatial segregation...
Multidecadal climate-induced variability in microseisms
R.C. Aster, D.E. McNamara, P.D. Bromirski
2008, Seismological Research Letters (79) 194-202
Microseisms are the most ubiquitous continuous seismic signals on Earth at periods between approximately 5 and 25 s (Peterson 1993; Kedar and Webb 2005). They arise from atmospheric energy converted to (primarily) Rayleigh waves via the intermediary of wind-driven oceanic swell and occupy a period band that is uninfluenced by...
More than 400 million years of evolution and some plants still can't make it on their own: Plant stress tolerance via fungal symbiosis
R. Rodriguez, R. Redman
2008, Conference Paper, Journal of Experimental Botany
All plants in natural ecosystems are thought to be symbiotic with mycorrhizal and/or endophytic fungi. Collectively, these fungi express different symbiotic lifestyles ranging from parasitism to mutualism. Analysis of Colletotrichum species indicates that individual isolates can express either parasitic or mutualistic lifestyles depending on the host genotype colonized. The endophyte...
Effects of scoria-cone eruptions upon nearby human communities
M.H. Ort, M.D. Elson, K.C. Anderson, W. A. Duffield, J.A. Hooten, D.E. Champion, G. Waring
2008, Geological Society of America Bulletin (120) 476-486
Scoria-cone eruptions are typically low in volume and explosivity compared with eruptions from stratovolcanoes, but they can affect local populations profoundly. Scoria-cone eruption effects vary dramatically due to eruption style, tephra blanket extent, climate, types of land use, the culture and complexity of the affected group, and resulting governmental action....
Creation of a continent recorded in zircon zoning
D.E. Moser, J. R. Bowman, J. Wooden, J.W. Valley, F. Mazdab, N. Kita
2008, Geology (36) 239-242
We have discovered a robust microcrystalline record of the early genesis of North American lithosphere preserved in the U-Pb age and oxygen isotope zoning of zircons from a lower crustal paragneiss in the Neoarchean Superior province. Detrital igneous zircon cores with ??18O values of 5.1???-7.1??? record creation of primitive to...
Eruption dynamics at Mount St. Helens imaged from broadband seismic waveforms: Interaction of the shallow magmatic and hydrothermal systems
G.P. Waite, B. A. Chouet, P.B. Dawson
2008, Journal of Geophysical Research B: Solid Earth (113)
The current eruption at Mount St. Helens is characterized by dome building and shallow, repetitive, long-period (LP) earthquakes. Waveform cross-correlation reveals remarkable similarity for a majority of the earthquakes over periods of several weeks. Stacked spectra of these events display multiple peaks between 0.5 and 2 Hz that are common...
Temporal downscaling of decadal sediment load estimates to a daily interval for use in hindcast simulations
N. K. Ganju, N. Knowles, D. H. Schoellhamer
2008, Journal of Hydrology (349) 512-523
In this study we used hydrologic proxies to develop a daily sediment load time-series, which agrees with decadal sediment load estimates, when integrated. Hindcast simulations of bathymetric change in estuaries require daily sediment loads from major tributary rivers, to capture the episodic delivery of sediment during multi-day freshwater flow pulses....
Gender identification of Caspian Terns using external morphology and discriminant function analysis
Joshua T. Ackerman, John Y. Takekawa, J.D. Bluso, J.L. Yee, Collin A. Eagles-Smith
2008, Wilson Journal of Ornithology (120) 378-383
Caspian Tern (Sterna caspia) plumage characteristics are sexually monochromatic and gender cannot easily be distinguished in the field without extensive behavioral observations. We assessed sexual size dimorphism and developed a discriminant function to assign gender in Caspian Terns based on external morphology. We collected and measured Caspian Terns in San...
