Validation of daily ring deposition in the otoliths of age-0 channel catfish
P.C. Sakaris, E.R. Irwin
2008, North American Journal of Fisheries Management (28) 212-218
We developed and validated methods for estimating the daily age of age-0 channel catfish Ictalurus punctatus. Two clutches of channel catfish eggs were hatched in the laboratory; subsequently, one was stocked in a 186-m2 earthen nursery pond and the other in a 757-L outdoor circular tank. Before stocking, subsamples of...
Factors affecting bottom trawl catches: Implications for monitoring the fishes of Lake Superior
D.L. Yule, J.V. Adams, J.D. Stockwell, O. T. Gorman
2008, North American Journal of Fisheries Management (28) 109-122
An annual daytime bottom trawl survey of the Lake Superior fish community designed in 1978 does not adequately assess the entire community. Whereas recent studies have recommended that pelagic species be surveyed with a combination of acoustic and midwater trawling methods (AC-MT), we used bottom trawling to study the effects...
Relationships between microbial communities and environmental parameters at sites impacted by mining of volcanogenic massive sulfide deposits, Prince William Sound, Alaska
A. L. Foster, L. Munk, R.A. Koski, Wayne C. Shanks III, L.L. Stillings
2008, Applied Geochemistry (23) 279-307
The relations among geochemical parameters and sediment microbial communities were examined at three shoreline sites in the Prince William Sound, Alaska, which display varying degrees of impact by acid-rock drainage (ARD) associated with historic mining of volcanogenic massive sulfide deposits. Microbial communities were examined using total fatty acid methyl esters...
Ways of learning: Observational studies versus experiments
T.L. Shaffer, Douglas H. Johnson
2008, Journal of Wildlife Management (72) 4-13
Manipulative experimentation that features random assignment of treatments, replication, and controls is an effective way to determine causal relationships. Wildlife ecologists, however, often must take a more passive approach to investigating causality. Their observational studies lack one or more of the 3 cornerstones of experimentation: controls, randomization, and replication. Although...
Dynamic stresses, Coulomb failure, and remote triggering
David P. Hill
2008, Bulletin of the Seismological Society of America (98) 66-92
Dynamic stresses associated with crustal surface waves with 15-30-sec periods and peak amplitudes < 1 MPa are capable of triggering seismicity at sites remote from the generating mainshock under appropriate conditions. Coulomb failure models based on a frictional strength threshold offer one explanation for instances of rapid-onset triggered seismicity that...
Structural equation modeling for observational studies
J.B. Grace
2008, Journal of Wildlife Management (72) 14-22
Structural equation modeling (SEM) represents a framework for developing and evaluating complex hypotheses about systems. This method of data analysis differs from conventional univariate and multivariate approaches familiar to most biologists in several ways. First, SEMs are multiequational and capable of representing a wide array of complex hypotheses about how...
Relation between species assemblages of fishes and water quality in salt ponds and sloughs in South San Francisco Bay
F. Mejia, M. K. Saiki, John Y. Takekawa
2008, Southwestern Naturalist (53) 335-345
This study was conducted to characterize fishery resources inhabiting salt-evaporation ponds and sloughs in South San Francisco Bay, and to identify key environmental variables that influence distribution of fishes. The ponds, which were originally constructed and operated for commercial production of salt, have undergone preliminary modifications (installation of culverts, gates,...
Immunization of black-tailed prairie dog against plague through consumption of vaccine-laden baits
Tonie E. Rocke, Susan Smith, D.T. Stinchcomb, Jorge E. Osorio
2008, Journal of Wildlife Diseases (44) 930-937
Prairie dogs (Cynomys spp.) are highly susceptible to Yersinia pestis and, along with other wild rodents, are significant reservoirs of plague for other wildlife and humans in the western United States. A recombinant raccoon poxvirus, expressing the F1 antigen of Y. pestis, was incorporated into a palatable bait and offered to three groups (n=18,...
A simulation model for projecting changes in salinity concentrations and species dominance in the coastal margin habitats of the Everglades
S.Y. Teh, D.L. DeAngelis, L.D.S.L. Sternberg, F. R. Miralles-Wilhelm, T.J. Smith, H. L. Koh
2008, Ecological Modelling (213) 245-256
Sharp boundaries typically separate the salinity tolerant mangroves from the salinity intolerant hardwood hammock species, which occupy the similar geographical areas of southern Florida. Evidence of strong feedback between tree community-type and the salinity of the unsaturated (vadose) zone of the soil suggests that a severe disturbance that significantly tilts...
Susceptibility to enhanced chemical migration from depression-focused preferential flow, High Plains aquifer
Jason J. Gurdak, Michelle Ann Walvoord, Peter B. McMahon
2008, Vadose Zone Journal (7) 1172-1184
Aquifer susceptibility to contamination is controlled in part by the inherent hydrogeologic properties of the vadose zone, which includes preferential-flow pathways. The purpose of this study was to investigate the importance of seasonal ponding near leaky irrigation wells as a mechanism for depression-focused preferential flow and enhanced chemical migration through...
Rare measurements of a sprite with halo event driven by a negative lightning discharge over Argentina
M.J. Taylor, M.A. Bailey, P.D. Pautet, S.A. Cummer, N. Jaugey, J.N. Thomas, N.N. Solorzano, Sabbas F. Sao, R.H. Holzworth, O. Pinto, N.J. Schuch
2008, Geophysical Research Letters (35)
As part of a collaborative campaign to investigate Transient Lummous Events (TLEs) over South America, coordinated optical, ELF/VLF, and lightning measurements were made of a mesoscale thunderstorm observed on February 22-23, 2006 over northern Argentina that produced 445 TLEs within a ???6 hour period. Here, we report comprehensive measurements of...
Cost-effective management alternatives for Snake river chinook salmon: A biological-economic synthesis
D.L. Halsing, M.R. Moore
2008, Conservation Biology (22) 338-350
The mandate to increase endangered salmon populations in the Columbia River Basin of North America has created a complex, controversial resource-management issue. We constructed an integrated assessment model as a tool for analyzing biological-economic trade-offs in recovery of Snake River spring- and summer-run chinook salmon (Oncorhynchus tshawytscha). We merged 3...
Correlation of the Deccan and Rajahmundry Trap lavas: Are these the longest and largest lava flows on Earth?
Stephen Self, Anne E. Jay, Michael Widdowson, Laszlo P. Keszthelyi
2008, Journal of Volcanology and Geothermal Research (172) 3-19
We propose that the Rajahmundry Trap lavas, found near the east coast of peninsular India,are remnants of the longest lava flows yet recognized on Earth (∼ 1000 km long). These outlying Deccan-like lavas are shown to belong to the main Deccan Traps. Several previous studies have already suggested this correlation, but have...
The distribution of nuclear genetic variation and historical demography of sea otters
A. Aguilar, David A. Jessup, J. Estes, J.C. Garza
2008, Animal Conservation (11) 35-45
The amount and distribution of population genetic variation is crucial information for the design of effective conservation strategies for endangered species and can also be used to provide inference about demographic processes and patterns of migration. Here, we describe variation at a large number of nuclear genes in sea otters...
Association among active seafloor deformation, mound formation, and gas hydrate growth and accumulation within the seafloor of the Santa Monica Basin, offshore California
C. K. Paull, W. R. Normark, W. Ussler III, D.W. Caress, R. Keaten
2008, Marine Geology (250) 258-275
Seafloor blister-like mounds, methane migration and gas hydrate formation were investigated through detailed seafloor surveys in Santa Monica Basin, offshore of Los Angeles, California. Two distinct deep-water (??? 800??m water depth) topographic mounds were surveyed using an autonomous underwater vehicle (carrying a multibeam sonar and a chirp sub-bottom profiler) and...
Near-surface location, geometry, and velocities of the Santa Monica Fault Zone, Los Angeles, California
R. D. Catchings, G. Gandhok, M. R. Goldman, D. Okaya, M. J. Rymer, G.W. Bawden
2008, Bulletin of the Seismological Society of America (98) 124-138
High-resolution seismic-reflection and seismic-refraction imaging, combined with existing borehole, earthquake, and paleoseismic trenching data, suggest that the Santa Monica fault zone in Los Angeles consists of multiple strands from several kilometers depth to the near surface. We interpret our seismic data as showing two shallow-depth low-angle fault strands and multiple...
Linking environmental risk assessment and communication: An experiment in co-evolving scientific and social knowledge
E.A. Graffy, N.L. Booth
2008, International Journal of Global Environmental Issues (8) 132-146
Dissemination of information to decision-makers and enhanced methods of public participation are often put forward as antidotes to a perceived disconnect between risk assessment and risk communication in the public domain. However, mechanisms that support both the provision of routine, timely and relevant technical knowledge to the public and meaningful...
Isotopic variations of dissolved copper and zinc in stream waters affected by historical mining
David M. Borrok, David Nimick, Richard B. Wanty, William I. Ridley
2008, Geochimica et Cosmochimica Acta (72) 329-344
Zinc and Cu play important roles in the biogeochemistry of natural systems, and it is likely that these interactions result in mass-dependent fractionations of their stable isotopes. In this study, we examine the relative abundances of dissolved Zn and Cu isotopes in a variety of stream waters draining six historical...
The 2005 eruption of Sierra Negra volcano, Galápagos, Ecuador
Dennis J. Geist, Karen S. Harpp, Terry R. Naumann, Michael P. Poland, William W. Chadwick, Minard Hall, Erika Rader
2008, Bulletin of Volcanology (70) 655-673
Sierra Negra volcano began erupting on 22 October 2005, after a repose of 26 years. A plume of ash and steam more than 13 km high accompanied the initial phase of the eruption and was quickly followed by a ~2-km-long curtain of lava fountains. The eruptive fissure opened inside the north rim...
Stratigraphic and compositional complexities of the late Quaternary Lethe tephra in South-central Alaska
J.R. Riehle, T. A. Ager, R.D. Reger, D.S. Pinney, D. S. Kaufman
2008, Quaternary International (178) 210-228
Recently discovered Lethe tephra has been proposed as a latest Pleistocene marker bed in Bristol Bay lowland NE to the Cook Inlet region, Alaska, on the basis of correlations involving a single "Lethe average" glass composition. Type deposits in the Valley of Ten Thousand Smokes, however, are chemically heterogeneous-individual lapilli...
Fish passage in a western Iowa stream modified by grade control structures
M.E. Litvan, C.L. Pierce, T.W. Stewart, C.J. Larson
2008, North American Journal of Fisheries Management (28) 1384-1397
Grade control structures (GCSs) are commonly used in streams of western Iowa to control bank erosion and channel headcutting but may be barriers to fish passage. From May 2002 to May 2006, we used mark-recapture methods to evaluate fish passage over a total of five GCSs, ranging in slope (run...
Biological and chemical characterization of metal bioavailability in sediments from Lake Roosevelt, Columbia River, Washington, USA
J.M. Besser, W. G. Brumbaugh, C.D. Ivey, C.G. Ingersoll, P.W. Moran
2008, Archives of Environmental Contamination and Toxicology (54) 557-570
We studied the bioavailability and toxicity of copper, zinc, arsenic, cadmium, and lead in sediments from Lake Roosevelt (LR), a reservoir on the Columbia River in Washington, USA that receives inputs of metals from an upstream smelter facility. We characterized chronic sediment toxicity, metal bioaccumulation, and metal concentrations in sediment...
Using heat to characterize streambed water flux variability in four stream reaches
H.I. Essaid, C.M. Zamora, K. A. McCarthy, J. R. Vogel, J.T. Wilson
2008, Journal of Environmental Quality (37) 1010-1023
Estimates of streambed water flux are needed for the interpretation of streambed chemistry and reactions. Continuous temperature and head monitoring in stream reaches within four agricultural watersheds (Leary Weber Ditch, IN; Maple Creek, NE; DR2 Drain, WA; and Merced River, CA) allowed heat to be used as a tracer to...
Analysis of trade-offs between threats of invasion by nonnative brook trout (Salvelinus fontinalis) and intentional isolation for native westslope cutthroat trout (Oncorhynchus clarkii lewisi)
D.P. Peterson, B.E. Rieman, J. B. Dunham, K.D. Fausch, M.K. Young
2008, Canadian Journal of Fisheries and Aquatic Sciences (65) 557-573
Native salmonid fishes often face simultaneous threats from habitat fragmentation and invasion by nonnative trout species. Unfortunately, management actions to address one may create or exacerbate the other. A consistent decision process would include a systematic analysis of when and where intentional use or removal of barriers is the most...
Talc friction in the temperature range 25°–400 °C: relevance for fault-zone weakening
Diane E. Moore, David A. Lockner
2008, Tectonophysics (449) 120-132
Talc is one of the weakest minerals that is associated with fault zones. Triaxial friction experiments conducted on water-saturated talc gouge at room temperature yield values of the coefficient of friction, μ(shear stress, τ/effective normal stress, σ′N) in the range 0.16–0.23, and μ increases with increasing σ′N. Talc gouge heated to temperatures of 100°–400 °C is...
