Depth distribution dynamics of the sculpin community in Lake Michigan
C.P. Madenjian, D.B. Bunnell
2008, Transactions of the American Fisheries Society (137) 1346-1357
Using data from our annual lakewide bottom trawl survey of Lake Michigan, we calculated the mean depths of capture for deepwater sculpin Myoxocephalus thompsonii and slimy sculpin Cottus cognatus for each combination of transect (Frankfort, Ludington, Saugatuck, and Manistique in Michigan, Waukegan in Illinois, and Port Washington and Sturgeon Bay...
Observations and interpretation of fundamental mode Rayleigh wavefields recorded by the Transportable Array (USArray)
F. F. Pollitz
2008, Journal of Geophysical Research B: Solid Earth (113)
Broadband recordings of the dense Transportable Array (TA) in the western United States provide unparalleled detailed images of long-period seismic surface wavefields. With 400 stations spanning most of the western United States, wavefronts of fundamental mode Rayleigh waves may be visualized coherently across the array at periods ???40 s. In...
An improved state-parameter analysis of ecosystem models using data assimilation
M. Chen, S. Liu, L.L. Tieszen, D.Y. Hollinger
2008, Ecological Modelling (219) 317-326
Much of the effort spent in developing data assimilation methods for carbon dynamics analysis has focused on estimating optimal values for either model parameters or state variables. The main weakness of estimating parameter values alone (i.e., without considering state variables) is that all errors from input, output, and model structure...
Model predictions of realgar precipitation by reaction of As(III) with synthetic mackinawite under anoxic conditions
T.J. Gallegos, Y.-S. Han, K.F. Hayes
2008, Environmental Science & Technology (42) 9338-9343
This study investigates the removal of As(III) from solution using mackinawite, a nanoparticulate reduced iron sulfide. Mackinawite suspensions (0.1−40 g/L) effectively lower initial concentrations of 1.3×10−5 M As(III) from pH 5−10, with maximum removal occurring under acidic conditions. Based on Eh measurements, it was found that the redox state of the system...
Trends and spatial distribution of annual and seasonal rainfall in Ethiopia
W.H. Cheung, G.B. Senay, A. Singh
2008, International Journal of Climatology (28) 1723-1734
As a country whose economy is heavily dependent on low-productivity rainfed agriculture, rainfall trends are often cited as one of the more important factors in explaining various socio-economic problems such as food insecurity. Therefore, in order to help policymakers and developers make more informed decisions, this study investigated the temporal...
Seasonal variation in sensitivity of larval sea lampreys to the lampricide 3-trifluoromethyl-4-nitrophenol
R.J. Scholefield, K.S. Slaght, B.E. Stephens
2008, North American Journal of Fisheries Management (28) 1609-1617
We evaluated the sensitivity of larval sea lampreys Petromyzon marinus to the lampricide 3-trifluoromethyl-4-nitrophenol (TFM) in a series of toxicity tests in spring and summer. Although noted previously, the seasonal variation in sensitivity to TFM had never been tested as a means of reducing TFM usage in stream treatments. A...
Mechanical and electromagnetic properties of northern Gulf of Mexico sediments with and without THF hydrates
J.Y. Lee, J.C. Santamarina, C. Ruppel
2008, Marine and Petroleum Geology (25) 884-895
Using an oedometer cell instrumented to measure the evolution of electromagnetic properties, small strain stiffness, and temperature, we conducted consolidation tests on sediments recovered during drilling in the northern Gulf of Mexico at the Atwater Valley and Keathley Canyon sites as part of the 2005 Chevron Joint Industry Project on...
Estimation of the bottleneck size in Florida panthers
M. Culver, P.W. Hedrick, K. Murphy, S. O'Brien, M.G. Hornocker
2008, Animal Conservation (11) 104-110
We have estimated the extent of genetic variation in museum (1890s) and contemporary (1980s) samples of Florida panthers Puma concolor coryi for both nuclear loci and mtDNA. The microsatellite heterozygosity in the contemporary sample was only 0.325 that in the museum samples although our sample size and number of loci...
Modeling mechanisms of vegetation change due to fire in a semi-arid ecosystem
J.D. White, K.J. Gutzwiller, W.C. Barrow, L.J. Randall, P. Swint
2008, Ecological Modelling (214) 181-200
Vegetation growth and community composition in semi-arid environments is determined by water availability and carbon assimilation mechanisms specific to different plant types. Disturbance also impacts vegetation productivity and composition dependent on area affected, intensity, and frequency factors. In this study, a new spatially explicit ecosystem model is presented for the...
Measuring real-time streamflow using emerging technologies: Radar, hydroacoustics, and the probability concept
J. Fulton, J. Ostrowski
2008, Journal of Hydrology (357) 1-10
Forecasting streamflow during extreme hydrologic events such as floods can be problematic. This is particularly true when flow is unsteady, and river forecasts rely on models that require uniform-flow rating curves to route water from one forecast point to another. As a result, alternative methods for measuring streamflow are needed...
Refraction tomography mapping of near-surface dipping layers using landstreamer data at East Canyon Dam, Utah
J. Ivanov, R. D. Miller, R.D. Markiewicz, J. Xia
2008, Conference Paper, SEG Technical Program Expanded Abstracts
We apply the P-wave refraction-tomography method to seismic data collected with a landstreamer. Refraction-tomography inversion solutions were determined using regularization parameters that provided the most realistic near-surface solutions that best matched the dipping layer structure of nearby outcrops. A reasonably well matched solution was obtained using an unusual set of...
Assessing manure management strategies through small-plot research and whole-farm modeling
A.M. Garcia, T.L. Veith, P.J.A. Kleinman, C.A. Rotz, L.S. Saporito
2008, Journal of Soil and Water Conservation (63) 204-211
Plot-scale experimentation can provide valuable insight into the effects of manure management practices on phosphorus (P) runoff, but whole-farm evaluation is needed for complete assessment of potential trade offs. Artificially-applied rainfall experimentation on small field plots and event-based and long-term simulation modeling were used to compare P loss in runoff...
Seasonal survival of radiomarked emperor geese in western Alaska
Jerry W. Hupp, Joel A. Schmutz, Craig R. Ely
2008, Journal of Wildlife Management (72) 1584-1595
The population of emperor geese (Chen canagica) in western Alaska, USA, declined by >50% from the 1960s to the mid‐1980s and has increased only slightly since. Rates of population increase among arctic geese are especially sensitive to changes in adult survival. Improving adult survival in seasons or geographic areas where...
Importance of physical and hydraulic characteristics to unionid mussels: A retrospective analysis in a reach of large river
S. J. Zigler, T.J. Newton, J. J. Steuer, M.R. Bartsch, J.S. Sauer
2008, Hydrobiologia (598) 343-360
Interest in understanding physical and hydraulic factors that might drive distribution and abundance of freshwater mussels has been increasing due to their decline throughout North America. We assessed whether the spatial distribution of unionid mussels could be predicted from physical and hydraulic variables in a reach of the Upper Mississippi...
Constraints on the Pleistocene chronology of sediments from the Lomonosov Ridge
M. O’Regan, J. King, J. Backman, M. Jakobsson, H. Palike, K. Moran, C. Heil, T. Sakamoto, T. M. Cronin, R.W. Jordan
2008, Paleoceanography (23)
Despite its importance in the global climate system, age-calibrated marine geologic records reflecting the evolultion of glacial cycles through the Pleistocene are largely absent from the central Arctic Ocean. This is especially true for sediments older than 200 ka. Three sites cored during the Integrated Ocean Drilling Program's Expedition 302,...
A trade-off between model resolution and variance with selected Rayleigh-wave data
J. Xia, R. D. Miller, Y. Xu
2008, Conference Paper, SEG Technical Program Expanded Abstracts
Inversion of multimode surface-wave data is of increasing interest in the near-surface geophysics community. For a given near-surface geophysical problem, it is essential to understand how well the data, calculated according to a layered-earth model, might match the observed data. A data-resolution matrix is a function of the data kernel...
Response in the water quality of the Salton Sea, California, to changes in phosphorus loading: An empirical modeling approach
Dale M. Robertson, S.G. Schladow
2008, Hydrobiologia (604) 5-19
Salton Sea, California, like many other lakes, has become eutrophic because of excessive nutrient loading, primarily phosphorus (P). A Total Maximum Daily Load (TMDL) is being prepared for P to reduce the input of P to the Sea. In order to better understand how P-load reductions should affect the average...
Water movement within the unsaturated zone in four agricultural areas of the United States
L.H. Fisher, R. W. Healy
2008, Journal of Environmental Quality (37) 1051-1063
Millions of tons of agricultural fertilizer and pesticides are applied annually in the USA. Due to the potential for these chemicals to migrate to groundwater, a study was conducted in 2004 using field data to calculate water budgets, rates of groundwater recharge and times of water travel through the unsaturated...
Herpetological Monitoring Using a Pitfall Trapping Design in Southern California
Robert Fisher, Drew Stokes, Carlton Rochester, Cheryl Brehme, Stacie Hathaway, Ted Case
2008, Techniques and Methods 2-A5
The steps necessary to conduct a pitfall trapping survey for small terrestrial vertebrates are presented. Descriptions of the materials needed and the methods to build trapping equipment from raw materials are discussed. Recommended data collection techniques are given along with suggested data fields. Animal specimen processing procedures, including toe- and...
Documentation of a Gulf sturgeon spawning site on the Yellow River, Alabama, USA
Brian R. Kreiser, J. Berg, M. Randall, F. Parauka, S. Floyd, B. Young, Kenneth J. Sulak
2008, Gulf and Caribbean Research (20) 91-95
The Gulf Sturgeon Recovery Plan (USFWS, GSMFC and NMFS 1995) stressed the need to provide maximum protection to Gulf sturgeon spawning habitat. The approach employed by various Gulf sturgeon researchers, including ourselves, to document spawning has been to identify potential spawning habitat on the basis of physical characteristics and/or tracking...
Age-class structure and variability of two populations of the bluemask darter etheostoma (Doration) sp.
J.W. Simmons, James B. Layzer, D.D. Smith
2008, American Midland Naturalist (160) 300-309
The bluemask darter Etheostoma (Doration) sp. is an endangered fish endemic to the upper Caney Fork system in the Cumberland River drainage in central Tennessee. Darters (Etheostoma spp.) are typically short-lived and exhibit rapid growth that quickly decreases with age. Consequently, estimating age of darters from length-frequency distributions can be...
Regional nitrate and pesticide trends in ground water in the eastern San Joaquin Valley, California
K.R. Burow, James L. Shelton, N. M. Dubrovsky
2008, Conference Paper, Journal of Environmental Quality
Protection of ground water for present and future use requires monitoring and understanding of the mechanisms controlling long-term quality of ground water. In this study, spatial and temporal trends in concentrations of nitrate and pesticides in ground water in the eastern San Joaquin Valley, California, were evaluated to determine the...
Differences in evaporation between a floating pan and class a pan on land
J.R. Masoner, D.I. Stannard, S. C. Christenson
2008, Journal of the American Water Resources Association (44) 552-561
Research was conducted to develop a method for obtaining floating pan evaporation rates in a small (less than 10,000 m2) wetland, lagoon, or pond. Floating pan and land pan evaporation data were collected from March 1 to August 31, 2005, at a small natural wetland located in the alluvium of the...
Downflow limestone beds for treatment of net-acidic, oxic, iron-laden drainage from a flooded anthracite mine, Pennsylvania, USA: 2. Laboratory evaluation
C.A. Cravotta III, S.J. Ward, J. M. Hammarstrom
2008, Mine Water and the Environment (27) 86-99
Acidic mine drainage (AMD) containing elevated concentrations of dissolved iron and other metals can be neutralized to varying degrees by reactions with limestone in passive treatment systems. We evaluated the chemical and mineralogical characteristics and the effectiveness of calcitic and dolomitic limestone for the neutralization of net-acidic, oxic, iron-laden AMD...
Decadal-scale changes of pesticides in ground water of the United States, 1993-2003
L. M. Bexfield
2008, Conference Paper, Journal of Environmental Quality
Pesticide data for ground water sampled across the United States between 1993-1995 and 2001-2003 by the U.S. Geological Survey National Water-Quality Assessment Program were evaluated for trends in detection frequency and concentration. The data analysis evaluated samples collected from a total of 362 wells located in 12 local well networks...
