Evolution of the Mazatzal province and the timing of the Mazatzal orogeny: Insights from U-Pb geochronology and geochemistry of igneous and metasedimentary rocks in southern New Mexico
J.M. Amato, A.O. Boullion, A.M. Serna, A.E. Sanders, G. L. Farmer, G. E. Gehrels, J. L. Wooden
2008, Geological Society of America Bulletin (120) 328-346
New U-Pb zircon ages, geochemistry, and Nd isotopic data are presented from three localities in the Paleoproterozoic Mazatzal province of southern New Mexico, United States. These data help in understanding the source regions and tectonic setting of magmatism from 1680 to 1620 Ma, the timing of the Mazatzal orogeny, the...
General and specialized media routinely employed for primary isolation of bacterial pathogens of fishes
C. E. Starliper
2008, Journal of Wildlife Diseases (44) 121-132
There are a number of significant diseases among cultured and free-ranging freshwater fishes that have a bacterial etiology; these represent a variety of gram-negative and gram-positive genera. Confirmatory diagnosis of these diseases involves primary isolation of the causative bacterium on bacteriologic media. Frequently used "general" bacteriologic media simply provide the...
Identifying habitat sinks: A case study of Cooper's hawks in an urban environment
R.W. Mannan, R.J. Steidl, C. W. Boal
2008, Urban Ecosystems (11) 141-148
We studied a population of Cooper's hawks (Accipiter cooperii) in Tucson, Arizona from 1994 to 2005. High rates of mortality of nestlings from an urban-related disease prompted speculation that the area represented an ecological trap and habitat sink for Cooper's hawks. In this paper, we used estimates of survival and...
Fluvial channels on Titan: Initial Cassini RADAR observations
R. D. Lorenz, R.M. Lopes, F. Paganelli, J. I. Lunine, Randolph L. Kirk, K. L. Mitchell, Laurence A. Soderblom, E. R. Stofan, G. Ori, M. Myers, H. Miyamoto, J. Radebaugh, B. Stiles, S. D. Wall, C. A. Wood
2008, Planetary and Space Science (56) 1132-1144
Cassini radar images show a variety of fluvial channels on Titan's surface, often several hundreds of kilometers in length. Some (predominantly at low- and mid-latitude) are radar-bright and braided, resembling desert washes where fines have been removed by energetic surface liquid flow, presumably from methane rainstorms. Others (predominantly at high...
Biogeochemical and ecological impacts of livestock grazing in semi-arid southeastern Utah, USA
D. P. Fernandez, J. C. Neff, R. L. Reynolds
2008, Journal of Arid Environments (72) 777-791
Relatively few studies have examined the ecological and biogeochemical effects of livestock grazing in southeastern Utah. In this study, we evaluated how grazing has affected soil organic carbon and nitrogen to a depth of 50 cm in grasslands located in relict and actively-grazed sites in the Canyonlands physiographic section of...
Nitrogen fluxes through unsaturated zones in five agricultural settings across the United States
C.T. Green, L.H. Fisher, B.A. Bekins
2008, Journal of Environmental Quality (37) 1073-1085
The main physical and chemical controls on nitrogen (N) fluxes between the root zone and the water table were determined for agricultural sites in California, Indiana, Maryland, Nebraska, and Washington from 2004 to 2005. Sites included irrigated and nonirrigated fields; soil textures ranging from clay to sand; crops including corn,...
Spectroscopy, morphometry, and photoclinometry of Titan's dunefields from Cassini/VIMS
J. W. Barnes, R. H. Brown, L. Soderblom, Christophe Sotin, S. Le Mouelic, S. Rodriguez, R. Jaumann, R.A. Beyer, B. J. Buratti, K. Pitman, K. H. Baines, R. Clark, P. Nicholson
2008, Icarus (195) 400-414
Fine-resolution (500 m/pixel) Cassini Visual and Infrared Mapping Spectrometer (VIMS) T20 observations of Titan resolve that moon's sand dunes. The spectral variability in some dune regions shows that there are sand-free interdune areas, wherein VIMS spectra reveal the exposed dune substrate. The interdunes from T20 are, variously, materials that correspond...
Natural radionuclide mobility and its influence on U-Th-Pb dating of secondary minerals from the unsaturated zone at Yucca Mountain, Nevada
L.A. Neymark, Y. V. Amelin
2008, Geochimica et Cosmochimica Acta (72) 2067-2089
Extreme U and Pb isotope variations produced by disequilibrium in decay chains of 238U and 232Th are found in calcite, opal/chalcedony, and Mn-oxides occurring as secondary mineral coatings in the unsaturated zone at Yucca Mountain, Nevada. These very slowly growing minerals (mm my-1) contain excess 206Pb and 208Pb formed from...
The effect of terrace geology on ground-water movement and on the interaction of ground water and surface water on a mountainside near Mirror Lake, New Hampshire, USA
T. C. Winter, D.C. Buso, P.C. Shattuck, P. T. Harte, D.A. Vroblesky, D.J. Goode
2008, Hydrological Processes (22) 21-32
The west watershed of Mirror Lake in the White Mountains of New Hampshire contains several terraces that are at different altitudes and have different geologic compositions. The lowest terrace (FSE) has 5 m of sand overlying 9 m of till. The two next successively higher terraces (FS2 and FS1) consist...
Estimation of walrus populations on sea ice with infrared imagery and aerial photography
Mark S. Udevitz, D. M. Burn, M.A. Webber
2008, Marine Mammal Science (24) 57-70
Population sizes of ice-associated pinnipeds have often been estimated with visual or photographic aerial surveys, but these methods require relatively slow speeds and low altitudes, limiting the area they can cover. Recent developments in infrared imagery and its integration with digital photography could allow substantially larger areas to be surveyed...
Influence of plankton mercury dynamics and trophic pathways on mercury concentrations of top predator fish of a mining-impacted reservoir
A.R. Stewart, M. K. Saiki, J.S. Kuwabara, Charles N. Alpers, M. Marvin-DiPasquale, D. P. Krabbenhoft
2008, Canadian Journal of Fisheries and Aquatic Sciences (65) 2351-2366
Physical and biogeochemical characteristics of the aquatic environment that affect growth dynamics of phytoplankton and the zooplankton communities that depend on them may also affect uptake of methylmercury (MeHg) into the pelagic food web of oligotrophic reservoirs. We evaluated changes in the quality and quantity of suspended particulate material, zooplankton...
Effective mitigation of debris flows at Lemon Dam, La Plata County, Colorado
V.G. deWolfe, P.M. Santi, J. Ey, J.E. Gartner
2008, Geomorphology (96) 366-377
To reduce the hazards from debris flows in drainage basins burned by wildfire, erosion control measures such as construction of check dams, installation of log erosion barriers (LEBs), and spreading of straw mulch and seed are common practice. After the 2002 Missionary Ridge Fire in southwest Colorado, these measures were...
Rainbow trout (Oncorhynchus mykiss) invasion and the spread of hybridization with native westslope cutthroat trout (Oncorhynchus clarkii lewisi)
M.C. Boyer, C.C. Muhlfeld, F.W. Allendorf
2008, Canadian Journal of Fisheries and Aquatic Sciences (65) 658-669
We analyzed 13 microsatellite loci to estimate gene flow among westslope cutthroat trout, Oncorhynchus clarkii lewisi, populations and determine the invasion pattern of hybrids between native O. c. lewisi and introduced rainbow trout, Oncorhynchus mykiss, in streams of the upper Flathead River system, Montana (USA) and British Columbia (Canada). Fourteen...
Translocation and early post-release demography of endangered Laysan teal
M.H. Reynolds, N.E. Seavy, M.S. Vekasy, J.L. Klavitter, L.P. Laniawe
2008, Animal Conservation (11) 160-168
In an attempt to reduce the high extinction risk inherent to small island populations, we translocated wild Laysan teal Anas laysanensis to a portion of its presumed prehistoric range. Most avian translocations lack the strategic post-release monitoring needed to assess early population establishment or failure. Therefore, we monitored the survival...
Effects of ionic strength, temperature, and pH on degradation of selected antibiotics
K.A. Loftin, C.D. Adams, M. T. Meyer, R. Surampalli
2008, Journal of Environmental Quality (37) 378-386
Aqueous degradation rates, which include hydrolysis and epimerization, for chlortetracycline (CTC), oxytetracycline (OTC), tetracycline (TET), lincomycin (LNC), sulfachlorpyridazine (SCP), sulfadimethoxine (SDM), sulfathiazole (STZ), trimethoprim (TRM), and tylosin A (TYL) were studied as a function of ionic strength (0.0015, 0.050, or 0.084 mg/L as Na2HPO4), temperature (7, 22, and 35°C), and...
Atmospheric contribution of gas emissions from Augustine volcano, Alaska during the 2006 eruption
K.A. McGee, M.P. Doukas, R. G. McGimsey, C.A. Neal, R.L. Wessels
2008, Geophysical Research Letters (35)
Airborne surveillance of gas emissions from Augustine for SO2, CO2 and H2S showed no evidence of anomalous degassing from 1990 through May 2005. By December 20, 2005, Augustine was degassing 660 td−1 of SO2, and ten times that by January 4, 2006. The highest SO2 emission rate measured during the 2006 eruption was...
Compound-specific isotope analysis: Questioning the origins of a trichloroethene plume
S. M. Eberts, C. Braun, S. Jones
2008, Environmental Forensics (9) 85-95
Stable carbon isotope ratios of trichloroethene (TCE), cis-1,2- dichloroethene, and trans-1,2-dichloroethene were determined by use of gas chromatography-combustion-isotope ratio mass spectroscopy to determine whether compound-specific stable carbon isotopes could be used to help understand the origin and history of a TCE groundwater plume in Fort Worth, TX. Calculated ??13C values...
Integrated impact of tropical cyclones on sea surface chlorophyll in the North Atlantic
M. N. Hanshaw, M.S. Lozier, J.B. Palter
2008, Geophysical Research Letters (35)
Past studies have shown that surface chlorophyll-a concentrations increase in the wake of hurricanes. Given the reported increase in the intensity of North Atlantic hurricanes in recent years, increasing chlorophyll-a concentrations, perhaps an indication of increasing biological productivity, would be an expected consequence. However, in order to understand the impact...
Impairment of the reproductive potential of male fathead minnows by environmentally relevant exposures to 4-nonylphenolf
H.L. Schoenfuss, S.E. Bartell, T.B. Bistodeau, R.A. Cediel, K.J. Grove, Larry Zintek, K. E. Lee, L. B. Barber
2008, Aquatic Toxicology (86) 91-98
The synthetic organic compound 4-nonylphenol (NP) has been detected in many human-impacted surface waters in North America. In this study, we examined the ability of NP to alter reproductive competence in male fathead minnows after a 28 day flow-through exposure in a range of...
High resolution shallow geologic characterization of a late Pleistocene eolian environment using ground penetrating radar and optically stimulated luminescence techniques: North Carolina, USA
D. Mallinson, S. Mahan, Christine Moore
2008, Southeastern Geology (45) 161-177
Geophysical surveys, sedimentology, and optically-stimulated luminescence age analyses were used to assess the geologic development of a coastal system near Swansboro, NC. This area is a significant Woodland Period Native American habitation and is designated the "Broad Reach" archaeological site. 2-d and 3-d subsurface geophysical surveys were performed using a...
Effect of hydrological conditions on nitrous oxide, methane, and carbon dioxide dynamics in a bottomland hardwood forest and its implication for soil carbon sequestration
K. Yu, S.P. Faulkner, M.J. Baldwin
2008, Global Change Biology (14) 798-812
This study was conducted at three locations in a bottomland hardwood forest with a distinct elevation and hydrological gradient: ridge (high, dry), transition, and swamp (low, wet). At each location, concentrations of soil greenhouse gases (N2O, CH4, and CO2), their fluxes to the atmosphere, and soil redox potential (Eh) were...
A quantitative evaluation of the iron-sulfur world and its relevance to life's origins
D.S. Ross
2008, Conference Paper, Astrobiology
The significance of Wa??chtersha??user's iron-sulfur world to the origin of life and the limits to its notional autocatalytic cycles are examined in kinetic simulations of the chain polymerization sequence primitive materials ??? amino acids ??? oligomers The simulations were run for the formation of all oligomers up to the 20-mer...
Embryo toxicity of 2,3,7,8-tetrachlorodibenzo-p-dioxin to the wood duck (Aix sponsa)
T.P. Augspurger, D. E. Tillitt, S.J. Bursian, S.D. Fitzgerald, D.E. Hinton, R.T. Di Giulio
2008, Archives of Environmental Contamination and Toxicology (55) 659-669
We examined the sensitivity of the wood duck (Aix sponsa) embryo to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) by injecting the toxicant into their eggs. Six groups of wood duck eggs (n = 35 to 211 per trial) were injected with 0 to 4600 pg TCDD/g egg between 2003 and 2005. Injections were made...
A rapid method for hydraulic profiling in unconsolidated formations
P. Dietrich, J.J. Butler Jr., K. Faiss
2008, Ground Water (46) 323-328
Information on vertical variations in hydraulic conductivity (K) can often shed much light on how a contaminant will move in the subsurface. The direct-push injection logger has been developed to rapidly obtain such information in shallow unconsolidated settings. This small-diameter tool consists of a short screen located just behind a...
Reproductive ecology of Actinonaias ligamentina (Bivalvia:Unionidae) in a regulated river
K.R. Moles, J.B. Layzer
2008, Journal of the North American Benthological Society (27) 212-222
Factors affecting the reproductive success of freshwater mussels in lotic systems are poorly understood. Gravidity, fecundity, and fertilization success of Actinonaias ligamentina were examined at 4 sites along a 63-km reach of the Green River immediately below the Green River Dam, Kentucky. No gravid females were collected at the site...
