A basin-scale approach to estimating stream temperatures of tributaries to the lower Klamath River, California
L. E. Flint, A. L. Flint
2008, Journal of Environmental Quality (37) 57-68
Stream temperature is an important component of salmonid habitat and is often above levels suitable for fish survival in the Lower Klamath River in northern California. The objective of this study was to provide boundary conditions for models that are assessing stream temperature on the main stem for the purpose...
Transient simulations of nitrogen load for a coastal aquifer and embayment, Cape Cod, MA
J.A. Colman, John P. Masterson
2008, Environmental Science & Technology (42) 207-213
A time-varying, multispecies, modular, three-dimensional transport model (MT3DMS) was developed to simulate groundwater transport of nitrogen from increasing sources on land to the shore of Nauset Marsh, a coastal embayment of the Cape Cod National Seashore. Simulated time-dependent nitrogen loads at the coast can be used to correlate with current...
Determination of dominant biogeochemical processes in a contaminated aquifer-wetland system using multivariate statistical analysis
S. E. Baez-Cazull, J.T. McGuire, I.M. Cozzarelli, M.A. Voytek
2008, Journal of Environmental Quality (37) 30-46
Determining the processes governing aqueous biogeochemistry in a wetland hydrologically linked to an underlying contaminated aquifer is challenging due to the complex exchange between the systems and their distinct responses to changes in precipitation, recharge, and biological activities. To evaluate temporal and spatial processes in the wetland-aquifer system, water samples...
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...
Visually assessing the level of development and soil surface stability of cyanobacterially dominated biological soil crusts
J. Belnap, S. L. Phillips, D.L. Witwicki, M. E. Miller
2008, Journal of Arid Environments (72) 1257-1264
Biological soil crusts (BSCs) are an integral part of dryland ecosystems and often included in long-term ecological monitoring programs. Estimating moss and lichen cover is fairly easy and non-destructive, but documenting cyanobacterial level of development (LOD) is more difficult. It requires sample collection for laboratory analysis, which causes soil surface...
Response of pendulums to complex input ground motion
V. Graizer, E. Kalkan
2008, Soil Dynamics and Earthquake Engineering (28) 621-631
Dynamic response of most seismological instruments and many engineering structures to ground shaking can be represented via response of a pendulum (single-degree-of-freedom oscillator). In most studies, pendulum response is simplified by considering the input from uni-axial translational motion alone. Complete ground motion however, includes not only translational components but also...
Distribution of pesticides, PAHs, PCBs, and bioavailable metals in depositional sediments of the lower Missouri River, USA
K. R. Echols, W. G. Brumbaugh, C.E. Orazio, T.W. May, B.C. Poulton, P.H. Peterman
2008, Archives of Environmental Contamination and Toxicology (55) 161-172
The lower Missouri River was studied to determine the distribution of selected persistent organic pollutants and bioavailable metals in depositional sediments. Nineteen sites between Omaha, Nebraska and Jefferson City, Missouri were sampled. This stretch of the river receives point-source and non-point-source inputs from industrial, urban, and agricultural activities. As part...
Reply to Bridge (2008) Discussion of articles in "Sedimentary features of tsunami deposits"
B. E. Jaffe, R.A. Morton, S. Kortekaas, A.G. Dawson, D.E. Smith, G. Gelfenbaum, I.D.L. Foster, D. Long, S. Shi
2008, Sedimentary Geology (211) 95-97
[No abstract available]...
Molecular and phenotypic diversity in Chionactis occipitalis (Western Shovel-nosed Snake), with emphasis on the status of C. o. klauberi (Tucson Shovel-nosed Snake).
D.A. Wood, J.M. Meik, A.T. Holycross, Robert N. Fisher, Amy G. Vandergast
2008, Conservation Genetics (9) 1489-1507
Chionactis occipitalis (Western Shovel-nosed Snake) is a small colubrid snake inhabiting the arid regions of the Mojave, Sonoran, and Colorado deserts. Morphological assessments of taxonomy currently recognize four subspecies. However, these taxonomic proposals were largely based on weak morphological differentiation and inadequate geographic sampling. Our goal was to explore evolutionary...
Ecosystem conceptual model- Mercury
Charles N. Alpers, Collin A. Eagles-Smith, Chris Foe, Susan Klasing, Mark C. Marvin-DiPasquale, Darell Slotton, Lisamarie Windham-Myers
2008, Report, Sacramento-San Joaquin Delta Regional Ecosystem Restoration Implementation Plan
Mercury has been identified as an important contaminant in the Delta, based on elevated concentrations of methylmercury (a toxic, organic form that readily bioaccumulates) in fish and wildlife. There are health risks associated with human exposure to methylmercury by consumption of sport fish, particularly top predators such as bass species....
U.S. federal water quality web service collaboration
J. Scott, D. Gellenbeck, D. Young, N. Booth
2008, Eos, Transactions, American Geophysical Union (89) 543-544
[No abstract available]...
The biological soil crusts of the San Nicolas Island: Enigmatic algae from a geographically isolated ecosystem
V.R. Flechtner, J.R. Johansen, J. Belnap
2008, Western North American Naturalist (68) 405-436
Composite soil samples from 7 sites on San Nicolas Island were evaluated quantitatively and qualitatively for the presence of cyanobacteria and eukaryotic microalgae. Combined data demonstrated a rich algal flora with 19 cyanobacterial and 19 eukaryotic microalgal genera being identified, for a total of 56 species. Nine new species were...
A consistent framework for Horton regression statistics that leads to a modified Hack's law
P.R. Furey, B.M. Troutman
2008, Geomorphology (102) 603-614
A statistical framework is introduced that resolves important problems with the interpretation and use of traditional Horton regression statistics. The framework is based on a univariate regression model that leads to an alternative expression for Horton ratio, connects Horton regression statistics to distributional simple scaling, and improves the accuracy in...
Dissolved and labile concentrations of Cd, Cu, Pb, and Zn in the South Fork Coeur d'Alene River, Idaho: Comparisons among chemical equilibrium models and implications for biotic ligand models
Laurie S. Balistrieri, R.G. Blank
2008, Applied Geochemistry (23) 3355-3371
In order to evaluate thermodynamic speciation calculations inherent in biotic ligand models, the speciation of dissolved Cd, Cu, Pb, and Zn in aquatic systems influenced by historical mining activities is examined using equilibrium computer models and the diffusive gradients in thin films...
Metalliferous sediment and a silica-hematite deposit within the Blanco fracture zone, Northeast Pacific
J.R. Hein, D.A. Clague, R.A. Koski, R.W. Embley, R.E. Dunham
2008, Marine Georesources and Geotechnology (26) 317-339
A Tiburon ROV dive within the East Blanco Depression (EBD) increased the mapped extent of a known hydrothermal field by an order of magnitude. In addition, a unique opal-CT (cristobalite-tridymite)-hematite mound was discovered, and mineralized sediments and rock were collected and analyzed. Silica-hematite mounds have not previously been found on...
Ichthyoplankton assemblages of coastal west-central Lake Erie and associated habitat characteristics
J.E. McKenna Jr., R. Douglas Hunter, M.C. Fabrizio, J.F. Savino, T. N. Todd, M. Bur
2008, Journal of Great Lakes Research (34) 755-769
Early life stage survival often determines fish cohort strength and that survival is affected by habitat conditions. The structure and dynamics of ichthyoplankton assemblages can tell us much about biodiversity and fish population dynamics, but are poorly understood in nearshore areas of the Great Lakes, where most spawning and nursery...
Diet composition and feeding periodicity of wild and hatchery subyearling Chinook salmon in Lake Ontario
J. H. Johnson
2008, Journal of Great Lakes Research (34) 590-598
Diel feeding periodicity, daily ration, and diet composition of wild and hatchery subyearling Chinook salmon Oncorhynchus tshawytscha were examined in Lake Ontario and the Salmon River, New York. The diet of wild riverine salmon was composed mainly of aquatic invertebrates (63.4%), mostly ephemeropterans (25.8%), chiromomids (15.8%), and trichopterans (8.3%). The...
Predators of Greater Sage-Grouse nests identified by video monitoring
P.S. Coates, J.W. Connelly, D.J. Delehanty
2008, Journal of Field Ornithology (79) 421-428
Nest predation is the primary cause of nest failure for Greater Sage-Grouse (Centrocercus urophasianus), but the identity of their nest predators is often uncertain. Confirming the identity of these predators may be useful in enhancing management strategies designed to increase nest success. From 2002 to 2005, we monitored 87 Greater...
Cliff swallows Petrochelidon pyrrhonota as bioindicators of environmental mercury, Cache Creek Watershed, California
Roger L. Hothem, Bonnie S. Trejo, Marissa L. Bauer, John J. Crayon
2008, Archives of Environmental Contamination and Toxicology (55) 111-121
To evaluate mercury (Hg) and other element exposure in cliff swallows (Petrochelidon pyrrhonota), eggs were collected from 16 sites within the mining-impacted Cache Creek watershed, Colusa, Lake, and Yolo counties, California, USA, in 1997-1998. Nestlings were collected from seven sites in 1998. Geometric mean total Hg (THg) concentrations ranged from...
Predicted effects of proposed new regulation plans on sedge/grass meadows of Lake Ontario
D.A. Wilcox, Y. Xie
2008, Journal of Great Lakes Research (34) 745-754
Previously described models for predicting the percent of Lake Ontario wetlands that would be occupied by sedge/grass-dominated meadow marsh were used to test four proposed new plans for regulation of lake levels and to make comparisons with the current plan and unregulated conditions. The models for drowned river mouth, barrier...
Experimental approaches to assessing the impact of a cesium chloride radiological dispersal device
S. Lee, Snyder E. Gibb, J. Barzyk, J. McGee, A. Koenig
2008, Conference Paper, Proceedings of the 31st AMOP Technical Seminar on Environmental Contamination and Response
The US EPA, as a part of the Chemical, Biological, Radiological-Nuclear, and Explosives (CBRNE) Research and Technology Initiative (CRTI) project team, is currently working to assess the impacts of an urban radiological dispersion device (RDD) and to develop containment and decontamination strategies. Three efforts in this area are currently underway:...
Evaluation of MODIS NDVI and NDWI for vegetation drought monitoring using Oklahoma Mesonet soil moisture data
Yingxin Gu, E. Hunt, B. Wardlow, J.B. Basara, Jesslyn F. Brown, J. P. Verdin
2008, Geophysical Research Letters (35) 1-5
The evaluation of the relationship between satellite-derived vegetation indices (normalized difference vegetation index and normalized difference water index) and soil moisture improves our understanding of how these indices respond to soil moisture fluctuations. Soil moisture deficits are ultimately tied to drought stress on plants. The diverse terrain and climate of...
Thermal stability of ladderane lipids as determined by hydrous pyrolysis
A. Jaeschke, M. D. Lewan, E.C. Hopmans, S. Schouten, Damste J.S. Sinninghe
2008, Organic Geochemistry (39) 1735-1741
Anaerobic ammonium oxidation (anammox) has been recognized as a major process resulting in loss of fixed inorganic nitrogen in the marine environment. Ladderane lipids, membrane lipids unique to anammox bacteria, have been used as markers for the detection of anammox in marine settings. However, the fate of ladderane lipids after...
Does urbanization influence the spatial ecology of Gila monsters in the Sonoran Desert?
M.A. Kwiatkowski, G.W. Schuett, R.A. Repp, E.M. Nowak, B.K. Sullivan
2008, Journal of Zoology (276) 350-357
To assess whether urbanization influences the spatial ecology of a rare and protected venomous reptilian predator, the Gila monster Heloderma suspectum, we compared home range (HR) size and movement parameters at three sites varying in degree of urbanization in the Sonoran Desert. We predicted that the urban population of H....
