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Maps Showing The Physical Hydrogeology And Changes In Saturated Thickness (Predevelopment To Spring 2016 And Spring 2011 To Spring 2016) In The Middle Republican Natural Resources District, Southwestern Nebraska., Jesse T. Korus Dr., Leslie M. Howard 2019 University of Nebraska-Lincoln

Maps Showing The Physical Hydrogeology And Changes In Saturated Thickness (Predevelopment To Spring 2016 And Spring 2011 To Spring 2016) In The Middle Republican Natural Resources District, Southwestern Nebraska., Jesse T. Korus Dr., Leslie M. Howard

Conservation and Survey Division

This report accompanies fourteen new maps summarizing the hydrogeology and changes in saturated thickness in the Middle Republican Natural Resources District (MRNRD). The purpose of these maps is to assist the MRNRD in their groundwater management programs and in planning and installing an observation well network. Maps include:

• base of the principal aquifer;

• water table surfaces for predevelopment, Spring 2011, and Spring 2016;

• saturated thicknesses for predevelopment, Spring 2011, and Spring 2016;

• changes in saturated thickness (both in absolute magnitude and in percent) from predevelopment to Spring 2016 and from Spring 2011 to Spring 2016;

• transmissivity.

A series of comprehensive ...


Refining The Onset Timing And Slip History Along The Northern Part Of The Teton Fault, Rachel Montague Hoar 2019 University of Kentucky

Refining The Onset Timing And Slip History Along The Northern Part Of The Teton Fault, Rachel Montague Hoar

Theses and Dissertations--Earth and Environmental Sciences

A new apatite (U-Th)/He (AHe) dataset from subvertical transects collected in the Teton and Gallatin Ranges in the Teton-Yellowstone region provides insight for the slip history and length of the Teton fault. Along the northernmost segment of the Teton fault, inverse thermal history modeling of AHe data from Eagles Rest Peak yield a ~9 Ma age for onset of fault slip. This age supports previous interpretations that Mount Moran may be the true center of the Teton fault. This refined interpretation coupled with lengthdisplacement fault scaling analysis and previous estimates of total fault displacement (~6 km) indicates that the ...


Response Of Vegetation In Open And Partially Wooded Fens To Prescribed Burning At Seney National Wildlife Refuge, Jane E. Austin, Wesley E. Newton 2019 U.S. Department of the Interior & U.S. Geological Survey

Response Of Vegetation In Open And Partially Wooded Fens To Prescribed Burning At Seney National Wildlife Refuge, Jane E. Austin, Wesley E. Newton

Publications of the US Geological Survey

The health and function of northern peatlands, particularly for fens, are strongly affected by fire and hydrology. Fens are important to several avian species of conservation interest, notably the yellow rail (Coturnicops noveboracensis). Fire suppression and altered hydrology often result in woody encroachment, altering the plant community and structure. Woody encroachment and its effects on biodiversity have become an increasing concern in the conservation and management of plant communities. This study evaluated the effects of spring and summer prescribed burns on the plant community, cover, and structure in open and partially wooded fens at Seney National Wildlife Refuge, Michigan, using ...


Mineral Exploration And Sustainable Development: A Case Study In The Republic Of South Sudan, Cosmas Pitia Kujjo 2019 University of Kentucky

Mineral Exploration And Sustainable Development: A Case Study In The Republic Of South Sudan, Cosmas Pitia Kujjo

Theses and Dissertations--Earth and Environmental Sciences

South Sudan, a new country formed in 2011, has been planning to develop its mineral sector by allocating exploration licenses to investors. This decision requires preliminary knowledge of geology and mineral occurrences, both of which are unavailable because the country has been engaged in a civil war for more than 50 years. Exploration of mineral resources in South Sudan has lagged behind its petroleum industry, except for artisanal gold mining, which is practiced intermittently by local communities. Freely available satellite gravity and remote-sensing data were used to map the basement architecture as well as zones of hydrothermal alteration in the ...


Mycorrhizal Colonization And Its Relationship With Plant Performance Differs Between Exotic And Native Grassland Plant Species, Aleksandra Checinska Sielaff, H. Wayne Polley, Andres Fuentes-Ramirez, Kirsten Hofmockel, Brian J. Wilsey 2019 Iowa State University

Mycorrhizal Colonization And Its Relationship With Plant Performance Differs Between Exotic And Native Grassland Plant Species, Aleksandra Checinska Sielaff, H. Wayne Polley, Andres Fuentes-Ramirez, Kirsten Hofmockel, Brian J. Wilsey

Ecology, Evolution and Organismal Biology Publications

Many grasslands have been transformed by exotic species with potentially novel ecological interactions. We hypothesized that exotic and native plant species differ, on average, in their percentage mycorrhizal colonization, and that mycorrhizal colonization is positively related to plant performance in the field. We compared colonization by arbuscular mycorrhizae (AM) fungi in perennial native and exotic species that were paired phylogenetically and by functional groups and grown under a common environment in field plots in Central Texas, USA. Roots were collected from plants in monoculture plots, stained, and percent colonization was assessed with a microscope. Aboveground biomass and dominance in mixture ...


High Resolution Spatial Variability In Spring Snowmelt For An Arctic Shrub-Tundra Watershed, Branden J. Walker, Philip Marsh Dr 2019 Wilfrid Laurier University

High Resolution Spatial Variability In Spring Snowmelt For An Arctic Shrub-Tundra Watershed, Branden J. Walker, Philip Marsh Dr

Theses and Dissertations (Comprehensive)

Arctic tundra environments are characterized by spatially heterogeneous end-of-winter snow cover because of high winds that erode, transport and deposit snow over the winter. This spatially variable end-of-winter snow cover subsequently influences the spatial and temporal variability of snowmelt and results in a patchy snowcover over the melt period. Documenting changes in both snow cover area (SCA) and snow water equivalent (SWE) during the spring melt is essential for understanding hydrological systems, but the lack of high-resolution SCA and SWE datasets that accurately capture micro-scale changes are not commonly available, and do not exist for the Canadian Arctic. This study ...


Characterization Of Claypan Soils In Southeastern Kansas, M. A. Mathis II, S. E. Tucker-Kulesza, G. F. Sassenrath 2019 Kansas State University

Characterization Of Claypan Soils In Southeastern Kansas, M. A. Mathis Ii, S. E. Tucker-Kulesza, G. F. Sassenrath

Kansas Agricultural Experiment Station Research Reports

Soil erosion reduces topsoil depth. In areas with a claypan, removal of productive topsoil reduces crop yield where the claypan layer is near the surface. The topsoil and claypan layer each have unique characteristics that impact crop production and within-field variability. To better understand these differences, the soil from an area of low crop yield and high crop yield were collected and laboratory tests were performed to determine the soil classification and undrained shear strength. Understanding the soil properties and the interaction between the topsoil and claypan layers may aid in under­standing the process by which topsoil is being ...


Changes In Soil Microbiology Under Conventional And No-Till Production During Crop Rotation, C. J. Hsiao, G. F. Sassenrath, L. Zeglin, G. Hettiarachchi, C. Rice 2019 Kansas State University

Changes In Soil Microbiology Under Conventional And No-Till Production During Crop Rotation, C. J. Hsiao, G. F. Sassenrath, L. Zeglin, G. Hettiarachchi, C. Rice

Kansas Agricultural Experiment Station Research Reports

Soil microbial activity is important for crop production. Soil microbes are involved in nutrient and water cycling within the soil, and interact with crop plants to provide the basic nutrient and water resources needed for crop production. Claypan soils have unique physical characteristics that impact soil biology. This study explored the tempo­ral changes in soil microbiology in a claypan soil under conventional and no-till produc­tion during a crop rotation of corn/winter wheat/soybean/fallow commonly planted in southeast Kansas. We found soil microbial activity changed more in the top two inches of soil than in the lower ...


Using Paleolimnology To Establish Baseline Conditions For Metal Contaminants In Advance Of Proposed Mining To Inform A Northern Community-Led Aquatic Monitoring Program, Tłı̨Chǫ Lands, Northwest Territories, Canada., James Telford 2019 Wilfrid Laurier University

Using Paleolimnology To Establish Baseline Conditions For Metal Contaminants In Advance Of Proposed Mining To Inform A Northern Community-Led Aquatic Monitoring Program, Tłı̨Chǫ Lands, Northwest Territories, Canada., James Telford

Theses and Dissertations (Comprehensive)

The Marian Watershed Stewardship Program (MWSP), a community-driven aquatic ecosystem monitoring program, was developed by the Tłı̨chǫ Government to address concerns regarding the cumulative impacts of multiple potential stressors. In particular, the MWSP aims to develop methods that will be effective for detecting potential pollution from the proposed cobalt-gold-copper-bismuth NICO mine within Tłı̨chǫ Lands. In collaboration with the MWSP, paleolimnological methods and geochemical normalization are used to establish pre-mine baselines of lake sediment metals concentrations in the Marian River watershed prior to mine development. This baseline framework can be used to assess for pollution from surficial sediment once ...


Biogeochemical And Hydrological Impacts Of A Low-Severity Wildfire In The Wetland-Dominated Zone Of Discontinuous Permafrost, Caren J. Ackley 2019 Wilfrid Laurier University

Biogeochemical And Hydrological Impacts Of A Low-Severity Wildfire In The Wetland-Dominated Zone Of Discontinuous Permafrost, Caren J. Ackley

Theses and Dissertations (Comprehensive)

Northern regions are experiencing rapid climate warming. As these regions warm, the occurrences of naturally ignited wildfires are increasing in frequency, severity and area burned, calling for a more thorough understanding of post-fire eco-hydrological impacts. Changes in runoff chemistry, and soil moisture and thermal regimes, have been attributed to the significant loss of organic matter (OM) and exposure of deeper soils, leading to enhanced permafrost degradation, ground surface subsidence and the conversion of peat landscapes from long-term C sinks to sources. However, low-severity wildfires often result in minor OM loss. Due to the significant and immediate threats posed to the ...


Geomorphic Effects Of Engineered Log Structures And Response To A Catastrophic Flood Event In A Missouri Ozarks River, Joseph S. Nash 2019 Missouri State University

Geomorphic Effects Of Engineered Log Structures And Response To A Catastrophic Flood Event In A Missouri Ozarks River, Joseph S. Nash

MSU Graduate Theses

Engineered log structures (ELSs) composed of local tree logs have been installed in river channels throughout the Pacific Northwest as a restoration technique. However, ELSs have not been tested for use in the Ozark Highlands until recently. In October 2016 the U.S. Forest Service installed four ELSs to stabilize banks along the North Fork of the White River in Ozark County, Missouri. The purpose here is to report on monitoring studies of pre- and post-restoration channel conditions and to assess geomorphic responses to floods. Over a ten-day period in April 2017 there were two bankfull floods, and on April ...


Cheating The (Eco)System: Potential For Invasive Grass Growth Above Treeline, Halina North 2019 University of Colorado, Boulder

Cheating The (Eco)System: Potential For Invasive Grass Growth Above Treeline, Halina North

Undergraduate Honors Theses

Invasive species are increasing in abundance globally and have had detrimental effects on ecosystems by altering nutrient cycling and harming native biodiversity. Generally, high-elevation alpine ecosystems are believed to be the least invaded global biomes. One particularly problematic invasive in the American West is Bromus tectorum, commonly known as Cheatgrass, which is an aggressive competitor and can displace native species. While there is a plethora of research concerning its invasive range in the Great Basin, few studies have addressed what inhibits growth at its high elevation range margin. An earlier study showed that while increased temperatures and N deposition increased ...


Experimental Observation For Ooid Nucleation On Quartz Grains, Christopher Benben 2019 University of Colorado, Boulder

Experimental Observation For Ooid Nucleation On Quartz Grains, Christopher Benben

Undergraduate Honors Theses

Ooids are fascinating carbonate grains. What insights they can provide for Earth history, are still yet to be completely understood. Potential areas of interest include ancient seawater chemistry and the role of biotic factors in carbonate precipitation. Understanding the how and why of ooid formation remains an active area of research. This study examines the effect of nucleus composition on calcium carbonate precipitation for ooid growth. Abrasion mills were used to nucleate ooids onto quartz grains of multiple sizes. Low overall precipitation levels, as evidenced by both Camsizer imaging, and scanning electron microscope element mapping and imaging, may indicate an ...


Numerical Simulations Of Convection With A Horizontal Magnetic Field, Talal Al-Refae 2019 University of Colorado, Boulder

Numerical Simulations Of Convection With A Horizontal Magnetic Field, Talal Al-Refae

Undergraduate Honors Theses

A numerical study of magnetoconvection with a horizontal magnetic field in a plane layer geometry is conducted. Novel dynamical regimes are observed beyond those occurring in classical (i.e non-magnetic) Rayleigh-Bénard convection. Imposed magnetic field strengths up to Chandrasekhar numbers of Q = 106 are investigated. The most unstable flow configuration is two-dimensional rolls oriented parallel to the direction of the imposed magnetic field in which the induced magnetic field is identically zero. The convective roll structure exhibits a preferential flow alignment along the direction of the imposed magnetic field thereby sustaining an anisotropic flow field. Deviations away from the ...


Systematic Exploration Of The Inverse Cascade In Rapidly Rotating Convection, Mitchell Krouss 2019 University of Colorado, Boulder

Systematic Exploration Of The Inverse Cascade In Rapidly Rotating Convection, Mitchell Krouss

Undergraduate Honors Theses

A detailed investigation of the formation of large-scale vortices (LSVs) in rapidly rotating convection is carried out with an asymptotically-reduced model. The LSVs are generated by an inverse cascade of kinetic energy, which transfers kinetic energy from small length scales to large length scales. We can identify parameters, describing fluids, containing the presence of an inverse cascade by evaluating the transfer of kinetic energy to different wave numbers. We find a critical vertical Reynolds number that delineates the transition to flows which show a robust inverse cascade. The vertical Reynolds number can be fit with a multi-parameter power law, which ...


Bacterial Lipids In Holocene Sediments From Baffin Island: Insights Into Temperature Reconstructions In Arctic Environments, Lucy Camuti 2019 University of Colorado, Boulder

Bacterial Lipids In Holocene Sediments From Baffin Island: Insights Into Temperature Reconstructions In Arctic Environments, Lucy Camuti

Undergraduate Honors Theses

This research study assesses the validity of bacterial branched glycerol dialkyl glycerol tetraethers (brGDGTs) for temperature reconstructions in Arctic settings from a sediment core extracted from Brother of Fog lake, Baffin Island. The distribution of brGDGTs in lake sediments have been shown to correlate with mean annual air temperature (MAAT) and serve as a proxy for paleotemperature reconstructions. This study aims to reconstruct temperature variability over the Holocene (~11500 years) and the applicability of this proxy for high latitude lakes. The results show a large bias within the brGDGT-inferred temperature reconstruction when applying the Russell et al. 2018 calibration. Due ...


Comparison Of The Practical Applications And Limitations Of Insar And Structure From Motion Depictions Of Surface Elevation Flux For Academic Purposes, John Andrew Scherer 2019 University of Colorado, Boulder

Comparison Of The Practical Applications And Limitations Of Insar And Structure From Motion Depictions Of Surface Elevation Flux For Academic Purposes, John Andrew Scherer

Undergraduate Honors Theses

This paper seeks to identify the strengths and weaknesses of two remote sensing methods used for determining surface elevation flux (the difference in land surface elevation heights over a given time period): Interferometric Synthetic Aperture Radar (InSAR) and Drone Imagery processed using Structure from Motion (SFM) Techniques. This goal was accomplished by processing imagery from both platforms separately, before conducting a study of the same area and comparing the two methods analytically. A time-series of interferograms was generated on the study area of the Climax Mine and Mill near Leadville, CO and multiple drone flights were flown over an additional ...


Nitrogen Cycle Dynamics During The Cretaceous Oceanic Anoxic Event 2 (Oae2; ~94 Ma) In The Western Interior Seaway, Jonn M. van Oosten-Edl 2019 University of Colorado, Boulder

Nitrogen Cycle Dynamics During The Cretaceous Oceanic Anoxic Event 2 (Oae2; ~94 Ma) In The Western Interior Seaway, Jonn M. Van Oosten-Edl

Undergraduate Honors Theses

The Cretaceous Ocean Anoxic Event 2 (OAE2, ~94 Ma), a time period of high sea-level and a warm greenhouse climate, was characterized by enhanced marine productivity and carbon burial in sediments, which resulted in the widespread deposition of black shales and a global perturbation of the carbon cycle. While decades of research have disentangled complex ecological dynamics during OAE2, a detailed understanding of the nitrogen cycle during this event (i.e., nitrogen transformations through metabolic and/or water-column redox reactions), remains elusive. I present a high-resolution (~300-3,000 years) bulk organic nitrogen stable isotope record from an expanded sedimentary section ...


Multi-Diffusion Domain Modeling Of Meteorite 40ar/39ar Data, Evan Tucker 2019 University of Colorado, Boulder

Multi-Diffusion Domain Modeling Of Meteorite 40ar/39ar Data, Evan Tucker

Undergraduate Honors Theses

The majority of 40Ar/39Ar analyses involving extraterrestrial samples were collected from bulk rock samples due to fine grain sizes. This present challenges in modeling the diffusion kinetics and thermal histories of these samples because of the presence of multiple-diffusion domains. Since Lovera et al. (1989) developed the multi-diffusion domain (MDD) method of modeling, many attempts have been made to automate the modeling process. However, existing software to model diffusion parameters and thermal histories falls short in that it is either restricted in availability, restricted in flexibility, or is cumbersome to use. I have created a new program ...


Interpretation Of High Frequency Climate Signals In Antarctic Ice Cores, Wyatt Hansen 2019 University of Colorado, Boulder

Interpretation Of High Frequency Climate Signals In Antarctic Ice Cores, Wyatt Hansen

Undergraduate Honors Theses

Stable isotopes of hydrogen and oxygen in ice cores are useful for understanding hydrologic cycle processes, including local temperature, regional atmospheric circulation, and conditions at the moisture source. Spectral analysis of these isotopes, in terms of frequency content and the associated amplitudes, gives insight into the climate cycles that governed past climate changes. This study examines the West Antarctic Ice Sheet (WAIS) Divide ice core (WDC) and the South Pole ice core (SPC) using Multi-Taper Method (MTM) spectral analysis. The 3-7, 4-15, 15-30, and 30-50 year-1 bands are investigated in relation to past climate change. In prior studies, multi-year and ...


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