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University of Nebraska - Lincoln

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Articles 871 - 900 of 1402

Full-Text Articles in Oceanography and Atmospheric Sciences and Meteorology

Occurrence Of Antimicrobials And Antimicrobial Resistance Genes In Beef Cattle Storage Ponds And Swine Treatment Lagoons, Yuping Zhang, Chiqian Zhang, David B. Parker, Daniel D. Snow, Zhi Zhou, Xu Li Jan 2013

Occurrence Of Antimicrobials And Antimicrobial Resistance Genes In Beef Cattle Storage Ponds And Swine Treatment Lagoons, Yuping Zhang, Chiqian Zhang, David B. Parker, Daniel D. Snow, Zhi Zhou, Xu Li

Nebraska Water Center: Faculty Publications

Livestock manure treatment and storage structures are potential environmental sources of antimicrobials and antimicrobial resistance genes (ARGs). In this study, the occurrence of antimicrobials and ARGs was investigated in the water and the sludge compartments of beef cattle storage ponds and swine lagoons. Analysis was focused on two families of antimicrobials (sulfonamide and tetracycline) and the corresponding ARGs (sul1, sul2, tetO, tetQ and tetX). Results showed that the pseudo-partitioning coefficients of tetracyclines were higher than those of sulfonamides, suggesting different distributions of these two classes of antimicrobials between water and sludge. The ARGs tested were …

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Critical Research Needs For Successful Food Systems Adaptation To Climate Change, Michelle Miller, Molly Anderson, Charles A. Francis, Chad Kruger, Carol Barford, Jacob Park, Brent H. Mccown Jan 2013

Critical Research Needs For Successful Food Systems Adaptation To Climate Change, Michelle Miller, Molly Anderson, Charles A. Francis, Chad Kruger, Carol Barford, Jacob Park, Brent H. Mccown

Department of Agronomy and Horticulture: Faculty Publications

There is a growing sense of the fragility of agricultural production in the Global North and South and of increasing risks to food security, as scientific observations confirm significant changes in the Gulf Stream, polar ice, atmospheric CO2, methane release, and other measures of climate change. This sense is heightened as each of us experiences extreme weather, such as the increasing frequency of droughts, floods, unseasonal temperatures, and erratic seasonality. The central research challenge before us is how global, national, regional, and local food systems may adapt to accelerating climate change stresses and uncertainties to ensure the availability, …

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Climate Change: What Does It Mean For Nebraska?, Martha D. Shulski, Natalie A. Umphlett, Tapan B. Pathak, Kenneth G. Hubbard Jan 2013

Climate Change: What Does It Mean For Nebraska?, Martha D. Shulski, Natalie A. Umphlett, Tapan B. Pathak, Kenneth G. Hubbard

High Plains Regional Climate Center: Staff Publications

Because Nebraska’s location on the North American continent is far removed from large bodies of water, Nebraskans experience a strong continental type climate. As such, residents do not benefit from the moderating influence of the ocean, and temperatures can have wide swings from day to day and season to season. Typical characteristics for a continental climate at this latitude are large temperature variability with warm summers dominated by convective thunderstorms, and cold winters influenced by snow and wind from mid-latitude cyclones.

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Impacts Of Migratory Sandhill Cranes (Grus Canadensis) On Microbial Water Quality In The Central Platte River, Nebraska, Usa, Jason R. Vogel, Dale W. Griffin, Hon S. Ip, Nicholas J. Ashbolt, Matthew T. Moser, Jingrang Lu, Mary K. Beitz, Hodon Ryu, Jorge W. Santo Domingo Jan 2013

Impacts Of Migratory Sandhill Cranes (Grus Canadensis) On Microbial Water Quality In The Central Platte River, Nebraska, Usa, Jason R. Vogel, Dale W. Griffin, Hon S. Ip, Nicholas J. Ashbolt, Matthew T. Moser, Jingrang Lu, Mary K. Beitz, Hodon Ryu, Jorge W. Santo Domingo

United States Geological Survey: Staff Publications

Wild birds have been shown to be significant sources of numerous types of pathogens that are relevant to humans and agriculture. The presence of large numbers of migratory birds in such a sensitive and important ecosystem as the Platte River in central Nebraska, USA, could potentially serve a significant source of birdderived pathogens in the water/sediment and riverine environment. In 2009 and 2010, a study was completed to investigate the potential water-quality impacts of Sandhill Cranes and Snow Geese on the microbial water quality of the central Platte River during their spring migration period. Fecal material, river-bottom sediment, and water …

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Controls On Recent Alaskan Lake Changes Identified From Water Isotopes And Remote Sensing, Lesleigh Anderson, Jennifer Rover, Nikki Gaulager, Jean Birks Jan 2013

Controls On Recent Alaskan Lake Changes Identified From Water Isotopes And Remote Sensing, Lesleigh Anderson, Jennifer Rover, Nikki Gaulager, Jean Birks

United States Geological Survey: Staff Publications

High-latitude lakes are important for terrestrial carbon dynamics and waterfowl habitat driving a need to better understand controls on lake area changes. To identify the existence and cause of recent lake area changes in the Yukon Flats, a region of discontinuous permafrost in north central Alaska, we evaluate remotely sensed imagery with lake water isotope compositions and hydroclimatic parameters. Isotope compositions indicate that mixtures of precipitation, river water, and groundwater source ~95% of the studied lakes. The remaining minority are more dominantly sourced by snowmelt and/or permafrost thaw. Isotope-based water balance estimates indicate 58% of lakes lose more than half …

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Ice-Age Megafauna In Arctic Alaska: Extinction, Invasion, Survival, Daniel H. Mann, Pamela Groves, Michael L. Kunz, Richard E. Reanier, Benjamin V. Gaglioti Jan 2013

Ice-Age Megafauna In Arctic Alaska: Extinction, Invasion, Survival, Daniel H. Mann, Pamela Groves, Michael L. Kunz, Richard E. Reanier, Benjamin V. Gaglioti

United States Geological Survey: Staff Publications

Radical restructuring of the terrestrial, large mammal fauna living in arctic Alaska occurred between 14,000 and 10,000 years ago at the end of the last ice age. Steppe bison, horse, and woolly mammoth became extinct, moose and humans invaded, while muskox and caribou persisted. The ice age mega fauna was more diverse in species and possibly contained 6x more individual animals than live in the region today. Mega faunal biomass during the last ice age may have been 30x greater than present. Horse was the dominant species in terms of number of individuals. Lions, short-faced bears, wolves, and possibly grizzly …

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Loess And Its Geomorphic, Stratigraphic, And Paleoclimatic Significance In The Quaternary, Daniel R. Muhs Jan 2013

Loess And Its Geomorphic, Stratigraphic, And Paleoclimatic Significance In The Quaternary, Daniel R. Muhs

United States Geological Survey: Staff Publications

Loess is aeolian silt visible in the field as a sedimentary body. It covers a significant portion of the land surface of the Earth. Loess thickness, particle size, and carbonate content decrease downwind from sources, useful trends for paleowinds. Many loess sections consist of relatively thick deposits of mostly unaltered sediment with intercalated paleosols. Paleosols represent periods of landscape stability when loess deposition slowed significantly. Loess in most regions was deposited during glacial periods and paleosols formed during interglacial periods. Loess has the potential to record the timing and environment of glacial–interglacial cycles of the Quaternary on many continents.

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Assessing Total Nitrogen In Surface-Water Samples: Precision And Bias Of Analytical And Computational Methods, David L. Rus, Charles J. Patton, David K. Mueller, Charles G. Crawford Jan 2013

Assessing Total Nitrogen In Surface-Water Samples: Precision And Bias Of Analytical And Computational Methods, David L. Rus, Charles J. Patton, David K. Mueller, Charles G. Crawford

United States Geological Survey: Water Reports and Publications

The characterization of total-nitrogen (TN) concentrations is an important component of many surface-water-quality programs. However, three widely used methods for the determination of total nitrogen—(1) derived from the alkaline-persulfate digestion of whole-water samples (TN-A); (2) calculated as the sum of total Kjeldahl nitrogen and dissolved nitrate plus nitrite (TN-K); and (3) calculated as the sum of dissolved nitrogen and particulate nitrogen (TN-C)—all include inherent limitations. A digestion process is intended to convert multiple species of nitrogen that are present in the sample into one measureable species, but this process may introduce bias. TN-A results can be negatively biased in the …

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Riparian Evapotranspiration In Nebraska, Brent M. Hall, David L. Rus Jan 2013

Riparian Evapotranspiration In Nebraska, Brent M. Hall, David L. Rus

United States Geological Survey: Water Reports and Publications

With increasing demands being placed on the water resources of Nebraska, characterizing evapotranspiration (ET) from riparian vegetation has gained importance to water users and managers. This report summarizes and compares the results from several studies of the ET from cottonwood-dominated riparian forests, riparian grasslands, and common reed, Phragmites australis, in Nebraska. Reported results show that the highest seasonal ET amounts were associated with Phragmites australis, followed by riparian forests, with riparian grasslands experiencing the lowest total ET of the studied vegetation communities.

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Reviews Of Science For Science Librarians: Drought In The Agricultural And Geosciences Literature, Leslie M. Delserone, Adonna Fleming Jan 2013

Reviews Of Science For Science Librarians: Drought In The Agricultural And Geosciences Literature, Leslie M. Delserone, Adonna Fleming

University of Nebraska-Lincoln Libraries: Faculty Publications

Drought is a hot topic, given the climatic events of summer 2012 in the United States. This article provides a fundamental understanding of drought—its definitions, classifications, ratings, and impact on agriculture. Also included are introductions to drought-related research areas in the geosciences—specifically geology, hydrology, and atmospheric sciences—as well as pointers to reliable sources of information about drought from the agricultural and geosciences literature.

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The Floodplain Food Web Mosaic: A Study Of Its Importance To Salmon And Steelhead With Implications For Their Recovery, J. Ryan Bellmore, Colden V. Baxter, Kyle Martens, Patrick J. Connolly Jan 2013

The Floodplain Food Web Mosaic: A Study Of Its Importance To Salmon And Steelhead With Implications For Their Recovery, J. Ryan Bellmore, Colden V. Baxter, Kyle Martens, Patrick J. Connolly

United States Geological Survey: Staff Publications

Although numerous studies have attempted to place species of interest within the context of food webs, such efforts have generally occurred at small scales or disregard potentially important spatial heterogeneity. If food web approaches are to be employed to manage species, studies are needed that evaluate the multiple habitats and associated webs of interactions in which these species participate. Here, we quantify the food webs that sustain rearing salmon and steelhead within a floodplain landscape of the Methow River, Washington, USA, a location where restoration has been proposed to restore side channels in an attempt to recover anadromous fishes. We …

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Predictive Models For Escherichia Coli Concentrations At Inland Lake Beaches And Relationship Of Model Variables To Pathogen Detection, Donna S. Francy, Erin A. Stelzer, Joseph W. Duris, Amie M. G. Brady, John H. Harrison, Heather E. Johnson, Michael W. Ware Jan 2013

Predictive Models For Escherichia Coli Concentrations At Inland Lake Beaches And Relationship Of Model Variables To Pathogen Detection, Donna S. Francy, Erin A. Stelzer, Joseph W. Duris, Amie M. G. Brady, John H. Harrison, Heather E. Johnson, Michael W. Ware

United States Geological Survey: Staff Publications

Predictive models, based on environmental and water quality variables, have been used to improve the timeliness and accuracy of recreational water quality assessments, but their effectiveness has not been studied in inland waters. Sampling at eight inland recreational lakes in Ohio was done in order to investigate using predictive models for Escherichia coli and to understand the links between E. coli concentrations, predictive variables, and pathogens. Based upon results from 21 beach sites, models were developed for 13 sites, and the most predictive variables were rainfall, wind direction and speed, turbidity, and water temperature. Models were not developed at sites …

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The Malthusian–Darwinian Dynamic And The Trajectory Of Civilization, Jeffrey C. Nekola, Craig D. Allen, James H. Brown, Joseph R. Burger, Ana D. Davidson, Trevor S. Fristoe, Marcus J. Hamilton, Sean T. Hammond, Astrid Kodric-Brown, Norman Mercado-Silva, Jordan G. Okie Jan 2013

The Malthusian–Darwinian Dynamic And The Trajectory Of Civilization, Jeffrey C. Nekola, Craig D. Allen, James H. Brown, Joseph R. Burger, Ana D. Davidson, Trevor S. Fristoe, Marcus J. Hamilton, Sean T. Hammond, Astrid Kodric-Brown, Norman Mercado-Silva, Jordan G. Okie

United States Geological Survey: Staff Publications

Two interacting forces influence all populations: the Malthusian dynamic of exponential growth until resource limits are reached, and the Darwinian dynamic of innovation and adaptation to circumvent these limits through biological and/or cultural evolution. The specific manifestations of these forces in modern human society provide an important context for determining how humans can establish a sustainable relationship with the finite Earth.

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Reproductive Health Of Yellow Perch Perca Flavescens In Selected Tributaries Of The Chesapeake Bay, Vicki S. Blazer, Alfred E. Pinkney, Jill A. Jenkins, Luke R. Iwanowicz, Steven Minkkinen, Rassa O. Draugelis-Dale, James H. Uphoff Jan 2013

Reproductive Health Of Yellow Perch Perca Flavescens In Selected Tributaries Of The Chesapeake Bay, Vicki S. Blazer, Alfred E. Pinkney, Jill A. Jenkins, Luke R. Iwanowicz, Steven Minkkinen, Rassa O. Draugelis-Dale, James H. Uphoff

United States Geological Survey: Staff Publications

Reduced recruitment of yellow perch has been noted for a number of years in certain urbanized watersheds (South and Severn Rivers) of the Chesapeake Bay. Other rapidly developing watersheds such as Mattawoman Creek are more recently showing evidence of reduced recruitment of anadromous fishes. In this study, we used a battery of biomarkers to better document the reproductive health of adult yellow perch collected during spring spawning in 2007–2009. Perch were collected in the South and Severn Rivers, Mattawoman Creek and the less developed Choptank and Allen's Fresh watersheds for comparison. Gonadosomatic indices, plasma reproductive hormone concentrations, plasma vitellogenin concentrations …

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Performance Of Human Fecal Anaerobe-Associated Pcr-Based Assays In A Multi-Laboratory Method Evaluation Study, Blythe A. Layton, Yiping Cao, Darcy L. Ebentier, Kaitlyn Hanley, Elisenda Balleste, Joao Brandao, Muruleedhara Byappanahalli, Reagan Converse, Andreas H. Farnleitner, Jennifer Gentry-Shields, Maribeth L. Gidley, Michele Gourmelon, Chang Soo Lee, Jiyoung Lee, Solen Lozach, Tania Madi, Wim G. Meijer, Rachel Noble, Lindsay Peed, Georg H. Reischer, Raquel Rodrigues, Joan B. Rose, Alexander Schriewer, Chris Sinigalliano, Sangeetha Srinivasan, Jill Stewart, Laurie C. Van De Werfhorst, Dan Wang, Richard Whitman, Stefan Wuertz, Jenny Jay, Patricia A. Holden, Alexandria B. Boehm, Orin Shanks, John F. Griffith Jan 2013

Performance Of Human Fecal Anaerobe-Associated Pcr-Based Assays In A Multi-Laboratory Method Evaluation Study, Blythe A. Layton, Yiping Cao, Darcy L. Ebentier, Kaitlyn Hanley, Elisenda Balleste, Joao Brandao, Muruleedhara Byappanahalli, Reagan Converse, Andreas H. Farnleitner, Jennifer Gentry-Shields, Maribeth L. Gidley, Michele Gourmelon, Chang Soo Lee, Jiyoung Lee, Solen Lozach, Tania Madi, Wim G. Meijer, Rachel Noble, Lindsay Peed, Georg H. Reischer, Raquel Rodrigues, Joan B. Rose, Alexander Schriewer, Chris Sinigalliano, Sangeetha Srinivasan, Jill Stewart, Laurie C. Van De Werfhorst, Dan Wang, Richard Whitman, Stefan Wuertz, Jenny Jay, Patricia A. Holden, Alexandria B. Boehm, Orin Shanks, John F. Griffith

United States Geological Survey: Staff Publications

A number of PCR-based methods for detecting human fecal material in environmental waters have been developed over the past decade, but these methods have rarely received independent comparative testing in large multi-laboratory studies. Here, we evaluated ten of these methods (BacH, BacHum-UCD, Bacteroides thetaiotaomicron (BtH), BsteriF1, gyrB, HF183 endpoint, HF183 SYBR, HF183 Taqman®, HumM2, and Methanobrevibacter smithii nifH (Mnif)) using 64 blind samples prepared in one laboratory. The blind samples contained either one or two fecal sources from human, wastewater or non-human sources. The assay results were assessed for presence/absence of the human markers and also quantitatively while …

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Human-Caused Mortality Influences Spatial Population Dynamics: Pumas In Landscapes With Varying Mortality Risks, Jesse R. Newby, L. Scott Mills, Toni K. Ruth, Daniel H. Pletscher, Michael S. Mitchell, Howard B. Quigley, Kerry M. Murphy, Rich Desimone Jan 2013

Human-Caused Mortality Influences Spatial Population Dynamics: Pumas In Landscapes With Varying Mortality Risks, Jesse R. Newby, L. Scott Mills, Toni K. Ruth, Daniel H. Pletscher, Michael S. Mitchell, Howard B. Quigley, Kerry M. Murphy, Rich Desimone

United States Geological Survey: Staff Publications

An understanding of how stressors affect dispersal attributes and the contribution of local populations to multi-population dynamics are of immediate value to basic and applied ecology. Puma (Puma concolor) populations are expected to be influenced by inter-population movements and susceptible to human induced source–sink dynamics. Using long-term datasets we quantified the contribution of two puma populations to operationally define them as sources or sinks. The puma population in the Northern Greater Yellowstone Ecosystem (NGYE) was largely insulated from human-induced mortality by Yellowstone National Park. Pumas in the western Montana Garnet Mountain system were exposed to greater human-induced mortality, …

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A Causal Examination Of The Effects Of Confounding Factors On Multimetric Indices, Donald R. Schoolmaster Jr., James B. Grace, E. William Schweiger, Brian R. Mitchell, Glenn R. Guntenspergen Jan 2013

A Causal Examination Of The Effects Of Confounding Factors On Multimetric Indices, Donald R. Schoolmaster Jr., James B. Grace, E. William Schweiger, Brian R. Mitchell, Glenn R. Guntenspergen

United States Geological Survey: Staff Publications

The development of multimetric indices (MMIs) as a means of providing integrative measures of ecosystem condition is becoming widespread. An increasingly recognized problem for the interpretability of MMIs is controlling for the potentially confounding influences of environmental covariates. Most common approaches to handling covariates are based on simple notions of statistical control, leaving the causal implications of covariates and their adjustment unstated. In this paper, we use graphical models to examine some of the potential impacts of environmental covariates on the observed signals between human disturbance and potential response metrics. Using simulations based on various causal networks, we show how …

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An Algorithmic And Information-Theoretic Approach To Multimetric Index Construction, Donald R. Schoolmaster Jr., James B. Grace, E. William Schweiger, Glenn R. Guntenspergen, Brian R. Mitchell, Kathryn M. Miller, Amanda M. Little Jan 2013

An Algorithmic And Information-Theoretic Approach To Multimetric Index Construction, Donald R. Schoolmaster Jr., James B. Grace, E. William Schweiger, Glenn R. Guntenspergen, Brian R. Mitchell, Kathryn M. Miller, Amanda M. Little

United States Geological Survey: Staff Publications

The use of multimetric indices (MMIs), such as the widely used index of biological integrity (IBI), to measure, track, summarize and infer the overall impact of human disturbance on biological communities has been steadily growing in recent years. Initially, MMIs were developed for aquatic communities using preselected biological metrics as indicators of system integrity. As interest in these bioassessment tools has grown, so have the types of biological systems to which they are applied. For many ecosystem types the appropriate biological metrics to use as measures of biological integrity are not known a priori. As a result, a variety of …

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Extending Airborne Electromagnetic Surveys For Regional Active Layer And Permafrost Mapping With Remote Sensing And Ancillary Data, Yukon Flats Ecoregion, Central Alaska, Neal J. Pastick, M. Torre Jorgenson, Bruce K. Wylie, Burke J. Minsley, Lei Ji, Michelle A. Walvoord, Bruce D. Smith, Jared D. Abraham, Joshua R. Rose Jan 2013

Extending Airborne Electromagnetic Surveys For Regional Active Layer And Permafrost Mapping With Remote Sensing And Ancillary Data, Yukon Flats Ecoregion, Central Alaska, Neal J. Pastick, M. Torre Jorgenson, Bruce K. Wylie, Burke J. Minsley, Lei Ji, Michelle A. Walvoord, Bruce D. Smith, Jared D. Abraham, Joshua R. Rose

United States Geological Survey: Staff Publications

Machine-learning regression tree models were used to extrapolate airborne electromagnetic resistivity data collected along flight lines in the Yukon Flats Ecoregion, central Alaska, for regional mapping of permafrost. This method of extrapolation (r = 0.86) used subsurface resistivity, Landsat Thematic Mapper (TM) at-sensor reflectance, thermal, TM-derived spectral indices, digital elevation models and other relevant spatial data to estimate near-surface (0–2.6-m depth) resistivity at 30-m resolution. A piecewise regression model (r = 0.82) and a presence/absence decision tree classification (accuracy of 87%) were used to estimate active-layer thickness (ALT) (< 101 cm) and the probability of near-surface (up to 123-cm depth) permafrost occurrence from field data, modelled near-surface (0–2.6m) resistivity, and other relevant remote sensing and map data. At site scale, the predicted ALTs were similar to those previously observed for different vegetation types. At the landscape scale, the predicted ALTs tended to be thinner on higher-elevation loess deposits than on low-lying alluvial and sand sheet deposits of the Yukon Flats. The ALT and permafrost maps provide a baseline for future permafrost monitoring, serve as inputs for modelling hydrological and carbon cycles at local to regional scales, and offer insight into the ALT response to fire and thaw processes. Published 2013. This article is a U.S. Government work and is in the public domain in the USA.

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A Review Of Environmental Impacts Of Salts From Produced Waters On Aquatic Resources, Aida M. Farag, David D. Harper Jan 2013

A Review Of Environmental Impacts Of Salts From Produced Waters On Aquatic Resources, Aida M. Farag, David D. Harper

United States Geological Survey: Staff Publications

Salts are frequently amajor constituent ofwastewaters produced during oil and gas production. These produced waters or brines must be treated and/or disposed and provide a daily challenge for operators and resourcemanagers. Some elements of salts are regulated with water quality criteria established for the protection of aquatic wildlife, e.g. chloride (Cl−), which has an acute standard of 860 mg/L and a chronic standard of 230 mg/L. However, data for establishing such standards has only recently been studied for other components of produced water, such as bicarbonate (HCO3 −), which has acute median lethal concentrations (LC50s) ranging from …

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Loess Origin, Transport, And Deposition Over The Past 10,000 Years, Wrangell-St. Elias National Park, Alaska, Daniel R. Muhs, James R. Budahn, John P. Mcgeehin, E. Arthur Bettis Iii, Gary Skipp, James B. Paces, Elisabeth A. Wheeler Jan 2013

Loess Origin, Transport, And Deposition Over The Past 10,000 Years, Wrangell-St. Elias National Park, Alaska, Daniel R. Muhs, James R. Budahn, John P. Mcgeehin, E. Arthur Bettis Iii, Gary Skipp, James B. Paces, Elisabeth A. Wheeler

United States Geological Survey: Staff Publications

Contemporary glaciogenic dust has not received much attention, because most research has been on glaciogenic dust of the last glacial period or non-glaciogenic dust of the present interglacial period. Nevertheless, dust from modern glaciogenic sources may be important for Fe inputs to primary producers in the ocean. Adjacent to the subarctic Pacific Ocean, we studied a loess section near Chitina, Alaska along the Copper River in Wrangell-St. Elias National Park, where dust has been accumulating over the past ~10,000 years. Mass accumulation rates for the fine-grained (<20 >µm) fraction of this loess section are among the highest reported for the …

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Chronology And Provenance Of Last-Glacial (Peoria) Loess In Western Iowa And Paleoclimatic Implications, Daniel R. Muhs, E. Arthur Bettis Iii, Helen M. Roberts, Stephen S. Harlan, James B. Paces, Richard L. Reynolds Jan 2013

Chronology And Provenance Of Last-Glacial (Peoria) Loess In Western Iowa And Paleoclimatic Implications, Daniel R. Muhs, E. Arthur Bettis Iii, Helen M. Roberts, Stephen S. Harlan, James B. Paces, Richard L. Reynolds

United States Geological Survey: Staff Publications

Geologic archives show that the Earth was dustier during the last glacial period. One model suggests that increased gustiness (stronger, more frequent winds) enhanced dustiness. We tested this at Loveland, Iowa, one of the thickest deposits of last-glacial-age (Peoria) loess in the world. Based on K/Rb and Ba/Rb, loess was derived not only from glaciogenic sources of the Missouri River, but also distal loess from non-glacial sources in Nebraska. Optically stimulated luminescence (OSL) ages provide the first detailed chronology of Peoria Loess at Loveland. Deposition began after ~27 ka and continued until ~17 ka. OSL ages also indicate that mass …

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Origin Of The Sinai-Negev Erg, Egypt And Israel: Mineralogical And Geochemical Evidence For The Importance Of The Nile And Sea Level History, Daniel R. Muhs, Joel Roskin, Haim Tsoar, Gary Skipp, James Budahn, Amihai Sneh, Naomi Porat, Jean-Daniel Stanley, Itzhak Katra, Dan G. Blumberg Jan 2013

Origin Of The Sinai-Negev Erg, Egypt And Israel: Mineralogical And Geochemical Evidence For The Importance Of The Nile And Sea Level History, Daniel R. Muhs, Joel Roskin, Haim Tsoar, Gary Skipp, James Budahn, Amihai Sneh, Naomi Porat, Jean-Daniel Stanley, Itzhak Katra, Dan G. Blumberg

United States Geological Survey: Staff Publications

The Sinai-Negev erg occupies an area of 13,000 km2 in the deserts of Egypt and Israel. Aeolian sand of this erg has been proposed to be derived from the Nile Delta, but empirical data supporting this view are lacking. An alternative source sediment is sand from the large Wadi El Arish drainage system in central and northern Sinai. Mineralogy of the Negev and Sinai dunes shows that they are high in quartz, with much smaller amounts of K-feldspar and plagioclase. Both Nile Delta sands and Sinai wadi sands, upstream of the dunes, also have high amounts of quartz relative …

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Toxic Exposure Of Songbirds To Lead In The Southeast Missouri Lead Mining District, W. Nelson Beyer, J. Christian Franson, John B. French, Thomas May, Barnett A. Rattner, Valerie I. Shearn-Bochsler, Sarah E. Warner, John Weber, David Mosby Jan 2013

Toxic Exposure Of Songbirds To Lead In The Southeast Missouri Lead Mining District, W. Nelson Beyer, J. Christian Franson, John B. French, Thomas May, Barnett A. Rattner, Valerie I. Shearn-Bochsler, Sarah E. Warner, John Weber, David Mosby

United States Geological Survey: Staff Publications

Mining and smelting in the Southeast Missouri Lead Mining District has caused widespread contamination of soils with lead (Pb) and other metals. Soils from three study sites sampled in the district contained from approximately 1,000–3,200 mg Pb/kg. Analyses of earthworms [33–4,600 mg Pb/kg dry weight (dw)] collected in the district showed likely high Pb exposure of songbirds preying on soil organisms. Mean tissue Pb concentrations in songbirds collected from the contaminated sites were greater (p < 0.05) than those in songbirds from reference sites by factors of 8 in blood, 13 in liver, and 23 in kidney. Ranges of Pb concentrations in livers (mg Pb/kg dw) were as follows: northern cardinal (Cardinalis cardinalis) = 0.11–3.0 (reference) and 1.3–30 (contaminated) and American robin (Turdus migratorius) = 0.43–8.5 (reference) and 7.6–72 (contaminated). Of 34 …

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Comparative Embryotoxicity Of A Pentabrominated Diphenyl Ether Mixture To Common Terns (Sterna Hirundo) And American Kestrels (Falco Sparverius), Barnett A. Rattner, Rebecca S. Lazarus, Gary H. Heinz, Natalie K. Karouna-Renier, Sandra L. Schultz, Robert C. Hale Jan 2013

Comparative Embryotoxicity Of A Pentabrominated Diphenyl Ether Mixture To Common Terns (Sterna Hirundo) And American Kestrels (Falco Sparverius), Barnett A. Rattner, Rebecca S. Lazarus, Gary H. Heinz, Natalie K. Karouna-Renier, Sandra L. Schultz, Robert C. Hale

United States Geological Survey: Staff Publications

Concentrations of polybrominated diphenyl ethers (PBDEs) in Forster’s tern (Sterna forsteri) eggs from San Francisco Bay have been reported to range up to 63 µg g-1 lipid weight. This value exceeds the lowest-observed-adverse-effect level (1.8 µg g-1 egg wet weight; ~32 µg g-1 lipid weight) reported in an embryotoxicity study with American kestrels (Falco sparverius). As a surrogate for Forster’s terns, common tern (Sterna hirundo) eggs were treated by air cell injection with corn oil vehicle (control) or a commercial penta-BDE formulation (DE-71) at nominal concentrations of 0.2, 2, and 20 µg g …

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A Global Standard For Monitoring Coastal Wetland Vulnerability To Accelerated Sea-Level Rise, Edward L. Webb, Daniel A. Friess, Ken W. Krauss, Donald R. Cahoon, Glenn R. Guntenspergen, Jacob Phelps Jan 2013

A Global Standard For Monitoring Coastal Wetland Vulnerability To Accelerated Sea-Level Rise, Edward L. Webb, Daniel A. Friess, Ken W. Krauss, Donald R. Cahoon, Glenn R. Guntenspergen, Jacob Phelps

United States Geological Survey: Staff Publications

Sea-level rise threatens coastal salt-marshes and mangrove forests around the world, and a key determinant of coastal wetland vulnerability is whether its surface elevation can keep pace with rising sea level. Globally, a large data gap exists because wetland surface and shallow subsurface processes remain unaccounted for by traditional vulnerability assessments using tide gauges. Moreover, those processes vary substantially across wetlands, so modelling platforms require relevant local data. The low-cost, simple, high-precision rod surface-elevation table–marker horizon (RSET-MH) method fills this critical data gap, can be paired with spatial data sets and modelling and is financially and technically accessible to every …

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Use Of Nmr Logging To Obtain Estimates Of Hydraulic Conductivity In The High Plains Aquifer, Nebraska, Usa, Katherine Dlubac, Rosemary Knight, Yi-Qiao Song, Nate Bachman, Ben Grau, Jim Cannia, John Williams Jan 2013

Use Of Nmr Logging To Obtain Estimates Of Hydraulic Conductivity In The High Plains Aquifer, Nebraska, Usa, Katherine Dlubac, Rosemary Knight, Yi-Qiao Song, Nate Bachman, Ben Grau, Jim Cannia, John Williams

United States Geological Survey: Staff Publications

Hydraulic conductivity (K) is one of the most important parameters of interest in groundwater applications because it quantifies the ease with which water can flow through an aquifer material. Hydraulic conductivity is typically measured by conducting aquifer tests or wellbore flow (WBF) logging. Of interest in our research is the use of proton nuclear magnetic resonance (NMR) logging to obtain information about water-filled porosity and pore space geometry, the combination of which can be used to estimate K. In this study, we acquired a suite of advanced geophysical logs, aquifer tests, WBF logs, and sidewall cores at the …

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Spatially Explicit Models For Inference About Density In Unmarked Or Partially Marked Populations, Richard B. Chandler, J. Andrew Royle Jan 2013

Spatially Explicit Models For Inference About Density In Unmarked Or Partially Marked Populations, Richard B. Chandler, J. Andrew Royle

United States Geological Survey: Staff Publications

Recently developed spatial capture-recapture (SCR) models represent a major advance over traditional capture-recapture (CR) models because they yield explicit estimates of animal density instead of population size within an unknown area. Furthermore, unlike non-spatial CR methods, SCR models account for heterogeneity in capture probability arising from the juxtaposition of animal activity centers and sample locations. Although the utility of SCR methods is gaining recognition, the requirement that all individuals can be uniquely identified excludes their use in many contexts. In this paper, we develop models for situations in which individual recognition is not possible, thereby allowing SCR concepts to be …

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The Geologic Records Of Dust In The Quaternary, Daniel R. Muhs Jan 2013

The Geologic Records Of Dust In The Quaternary, Daniel R. Muhs

United States Geological Survey: Staff Publications

Study of geologic records of dust composition, sources and deposition rates is important for understanding the role of dust in the overall planetary radiation balance, fertilization of organisms in the world’s oceans, nutrient additions to the terrestrial biosphere and soils, and for paleoclimatic reconstructions. Both glacial and non-glacial processes produce fine-grained particles that can be transported by the wind. Geologic records of dust flux occur in a number of depositional archives for sediments: (1) loess deposits; (2) lake sediments; (3) soils; (4) deep-ocean basins; and (5) ice sheets and smaller glaciers. These archives have several characteristics that make them highly …

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Metr 200: Weather And Climate—A Peer Review Of Teaching Project Benchmark Portfolio, Matthew S. Van Den Broeke Jan 2013

Metr 200: Weather And Climate—A Peer Review Of Teaching Project Benchmark Portfolio, Matthew S. Van Den Broeke

UNL Faculty Course Portfolios

This benchmark portfolio is meant to be an assessment of how well the objectives of METR 200 (Weather and Climate) are being attained by students in several classifications of academic major. Students from a wide range of backgrounds enroll in this course as a general science elective, and for many, it will be the only science course taken in college. Thus, it is important that course material be sufficiently accessible for all students, while providing meaningful information which will be applicable by students of all backgrounds once they leave the course. In this portfolio, an analysis will be presented showing …

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