Open Access. Powered by Scholars. Published by Universities.®
- Discipline
-
- Geology (511)
- Environmental Sciences (363)
- Hydrology (291)
- Life Sciences (257)
- Oceanography and Atmospheric Sciences and Meteorology (177)
-
- Water Resource Management (163)
- Other Earth Sciences (151)
- Environmental Monitoring (133)
- Geophysics and Seismology (129)
- Other Environmental Sciences (125)
- Plant Sciences (116)
- Soil Science (108)
- Environmental Indicators and Impact Assessment (96)
- Geochemistry (82)
- Climate (81)
- Animal Sciences (79)
- Natural Resources Management and Policy (79)
- Social and Behavioral Sciences (74)
- Engineering (72)
- Natural Resources and Conservation (70)
- Forest Sciences (68)
- Sustainability (68)
- Environmental Health and Protection (65)
- Agriculture (62)
- Natural Resource Economics (62)
- Sedimentology (54)
- Geomorphology (50)
- Civil and Environmental Engineering (46)
- Institution
-
- University of Nebraska - Lincoln (205)
- Western Kentucky University (64)
- University of Kentucky (55)
- University of South Florida (55)
- University of Arkansas, Fayetteville (47)
-
- Missouri University of Science and Technology (40)
- Utah State University (38)
- City University of New York (CUNY) (34)
- Boise State University (30)
- TÜBİTAK (30)
- Portland State University (29)
- University of Colorado Law School (29)
- West Virginia University (29)
- Purdue University (24)
- University of Texas at El Paso (24)
- Michigan Technological University (23)
- Old Dominion University (22)
- University of South Carolina (21)
- Central Washington University (18)
- Louisiana State University (18)
- Stephen F. Austin State University (16)
- Western Michigan University (16)
- Brigham Young University (15)
- Illinois State University (15)
- National Taiwan Ocean University (14)
- University of Texas Rio Grande Valley (14)
- University of New Hampshire (13)
- Western University (13)
- Wright State University (13)
- Montana Tech Library (12)
- Keyword
-
- Geology (52)
- Earth sciences (43)
- Geochemistry (34)
- Groundwater (22)
- Climate change (16)
-
- Hydrogeology (15)
- Drought (14)
- Hydrology (14)
- News (14)
- Utah Water Research Laboratory (14)
- GIS (13)
- Karst (13)
- UWRL (13)
- Water quality (13)
- Biological sciences (12)
- Irrigation (12)
- Agriculture (11)
- Eras (11)
- Periods (11)
- Remote sensing (11)
- Seismic (11)
- Stratigraphy (11)
- Applied sciences (10)
- Geophysics (10)
- Tectonics (10)
- Antarctica (9)
- Cretaceous (9)
- Evapotranspiration (9)
- Geomorphology (9)
- Soil (9)
- Publication
-
- Mammoth Cave Research Symposia (53)
- United States Geological Survey: Staff Publications (47)
- United States Agricultural Commodities in Drought Archive (42)
- Theses and Dissertations (40)
- Graduate Theses and Dissertations (32)
-
- Masters Theses (31)
- Turkish Journal of Earth Sciences (30)
- Electronic Theses and Dissertations (27)
- Readings and Notes (27)
- School of Geosciences Faculty and Staff Publications (25)
- Open Access Theses & Dissertations (24)
- Publications and Research (24)
- Coping with Water Scarcity in River Basins Worldwide: Lessons Learned from Shared Experiences (Martz Summer Conference, June 9-10) (22)
- Dissertations and Theses (19)
- Dissertations, Master's Theses and Master's Reports (19)
- USF Tampa Graduate Theses and Dissertations (18)
- Department of Earth and Atmospheric Sciences: Faculty Publications (17)
- Faculty Publications (16)
- National Drought Mitigation Center: Faculty Publications (15)
- Plant and Soil Sciences Faculty Publications (15)
- United States Environmental Protection Agency: Publications (15)
- Journal of Marine Science and Technology–Taiwan (14)
- News (14)
- Boise State University Theses and Dissertations (13)
- Earth Sciences Publications (13)
- Geosciences Faculty Publications and Presentations (13)
- Graduate Theses & Non-Theses (12)
- Kentucky Grazing Conference (12)
- Open Access Dissertations (12)
- School of Earth, Environmental, & Marine Sciences Faculty Publications (12)
- Publication Type
- File Type
Articles 511 - 540 of 1252
Full-Text Articles in Earth Sciences
Fire And Fuels: Vegetation Change Over Time In The Zuni Mountains, New Mexico, Luke Wylie
Fire And Fuels: Vegetation Change Over Time In The Zuni Mountains, New Mexico, Luke Wylie
Master's Theses
The Zuni Mountains are a region that has been dramatically changed by human interference. Anthropogenically, fire suppression practices have allowed a buildup of fuels and caused a change in the fire-adapted ponderosa pine ecosystem such that the new ecosystem now incorporates many fire-intolerant species. As a result, the low-severity fires that the ecosystem once depended on to regenerate the forest are much reduced, and these low-severity fires are now replaced by crown-level infernos that threaten the forest and nearby towns. In order to combat these effects, land managers are implementing fuel reduction practices and are striving to better understand the …
Alluvial Sedimentation Associated With Logging In Low Gradient Watersheds In Desoto National Forest, Mississippi, Andrew W. Simmons
Alluvial Sedimentation Associated With Logging In Low Gradient Watersheds In Desoto National Forest, Mississippi, Andrew W. Simmons
Master's Theses
Forestry and related businesses are an important factor of Mississippi’s economy, contributing between $11 and $14 billion annually (Mississippi Forestry Commission, 2006). The timber industry is not only important in Mississippi but is an important sector of the economy throughout the Gulf Coast region. While providing positive economic benefits to the region, the forestry industry can also negatively affect soil properties, hillslope stability, and increase sedimentation rates in local streams and rivers. The aim of this research is to determine if forestry removal causes an increase of soil erosion and how it affects floodplain sedimentation in the low gradient watershed …
Agroecosystem And Ecosystem Resiliency To Extreme Hydrometeorological And Climate Events, Katherine M. Werner
Agroecosystem And Ecosystem Resiliency To Extreme Hydrometeorological And Climate Events, Katherine M. Werner
Department of Agricultural and Biological Systems Engineering: Dissertations, Theses, and Student Research
The purpose of this study was to understand how a large-scale representation of agroecosystems and ecosystems respond to extreme hydrometeorological and climate extreme events (EHCE) within the Platte River Basin. The ability for agroecosystems and ecosystems to adapt to a changing and variable climate is vital for global water, energy, and food security. Two model experiments were performed, the first with a time span from 2000 to 2013 in which a dynamic leaf area index (LAI) MODIS15A2 product was implemented. The second experiment ran from 1950 through 2013 used a climatological fixed seasonal cycle calculated as the average from the …
Peccaries (Artiodactyla: Tayassuidae) From The Late Miocene To Early Pliocene Gray Fossil Site: Regional Implications With A Review Of Tayassuinae, Evan M. Doughty
Peccaries (Artiodactyla: Tayassuidae) From The Late Miocene To Early Pliocene Gray Fossil Site: Regional Implications With A Review Of Tayassuinae, Evan M. Doughty
Electronic Theses and Dissertations
Analysis of the Gray Fossil Site peccary material indicates the presence of up to three species. Comparisons with the tayassuid material known from the Tyner Farm and Bone Valley Formation of Florida allows the identification of Mylohyus elmorei and at the GFS. Within the GFS material, Prosthennops cf. P. serus and cf. Catagonus sp. are also tentatively recognized but further verification is required. The known range for Prosthennops is expanded into the Appalachian region. Presence of M. elmorei at the Gray Fossil Site provides the first known occurrence of this species outside of the Palmetto fauna of Florida, indicating that …
Potential And Timescales For Oxygen Depletion In Coastal Upwelling Systems: A Box-Model Analysis, Cheryl S. Harrison, B. Hales, S. Siedlecki, R. M. Samelson
Potential And Timescales For Oxygen Depletion In Coastal Upwelling Systems: A Box-Model Analysis, Cheryl S. Harrison, B. Hales, S. Siedlecki, R. M. Samelson
School of Earth, Environmental, & Marine Sciences Faculty Publications
A simple box model is used to examine oxygen depletion in an idealized ocean-margin upwelling system. Near-bottom oxygen depletion is controlled by a competition between flushing with oxygenated offshore source waters and respiration of particulate organic matter produced near the surface and retained near the bottom. Upwelling-supplied nutrients are consumed in the surface box, and some surface particles sink to the bottom where they respire, consuming oxygen. Steady states characterize the potential for hypoxic near-bottom oxygen depletion; this potential is greatest for faster sinking rates, and largely independent of production timescales except in that faster production allows faster sinking. Timescales …
Description, Taphonomy, And Paleoecology Of The Late Pleistocene Peccaries (Artiodactyla: Tayassuidae) From Bat Cave, Pulaski County, Missouri, Aaron L. Woodruff
Description, Taphonomy, And Paleoecology Of The Late Pleistocene Peccaries (Artiodactyla: Tayassuidae) From Bat Cave, Pulaski County, Missouri, Aaron L. Woodruff
Electronic Theses and Dissertations
The late Pleistocene faunal assemblage from Bat Cave, central Ozarks, Missouri provides an opportunity to assess specific aspects of behavior, ecology, and ontogeny of the extinct peccary Platygonus compressus. All identifiable elements referable to this taxon were catalogued and examined, and a minimum number of individuals of 70 was determined for the sample. The presence of distinct, non-overlapping age groups suggests that P. compressus utilized Bat Cave on a seasonal basis. A predator-prey relationship with Canis dirus, the second most abundant vertebrate from the Bat Cave site, is also described in this study. Damage patterns suggest that the …
New Records Of Colubrids From The Late Hemphillian Gray Fossil Site Of Northeastern Tennessee, Derek J. Jurestovsky
New Records Of Colubrids From The Late Hemphillian Gray Fossil Site Of Northeastern Tennessee, Derek J. Jurestovsky
Electronic Theses and Dissertations
The Gray Fossil Site is a rich Hemphillian (North American Land Mammal Age) locality located in northeastern Tennessee which has produced tens-of-thousands of fossils of multiple taxa including hundreds of individual snake skeletal remains. Analyzed here are cranial and vertebral fossils identified as belonging to various colubrid taxa including Carphophis sp., Gyalopion sp., Heterodon sp., Natricinae indeterminate, Thamnophis sp., and a new, undescribed genus and species. In addition, multiple new features of snake vertebrae are described, some of which question the validity of the genus Neonatrix. Finally, the distribution and paleoecology of the listed genera allows an interpretation of …
Validation Of An Internal Camera Based Volume Determination System For Triaxial Testing, Leah D. Miramontes
Validation Of An Internal Camera Based Volume Determination System For Triaxial Testing, Leah D. Miramontes
Civil Engineering Undergraduate Honors Theses
Accurate strain and volume measurements are critical to phase relationships and strength determination for saturated and unsaturated soils. In recent years, laboratory-based photographic techniques of monitoring soil specimens have become more common. These techniques have been used to reconstruct 3D models and to determine strain and volumetric changes of triaxial specimens. A new technique that utilized digital photographs of the soil specimen, captured from within a triaxial testing cell, was utilized. Photographs were processed using photogrammetry software to reconstruct 3D models of the soil specimens. By placing camera equipment within the cell, the technique eliminated the need to account for …
Analyzing The Phenologic Dynamics Of Kudzu (Pueraria Montana) Infestations Using Remote Sensing And The Normalized Difference Vegetation Index., Faye Peters
Electronic Theses and Dissertations
Non-native invasive species are one of the major threats to worldwide ecosystems. Kudzu (Pueraria montana) is a fast-growing vine native to Asia that has invaded regions in the United States making management of this species an important issue. Estimated normalized difference vegetation index (NDVI) values for the years 2000 to 2015 were calculated using data collected by Landsat and MODIS platforms for three infestation sites in Kentucky. The STARFM image-fusing algorithm was used to combine Landsat- and MODIS-derived NDVI into time series with a 30 m spatial resolution and 16 day temporal resolution. The fused time series was …
Resolving Paragneiss Provenance At Grollier Lake In The Athabasca Granulite Terrane, Western Canadian Shield, Dustin Ply
Resolving Paragneiss Provenance At Grollier Lake In The Athabasca Granulite Terrane, Western Canadian Shield, Dustin Ply
Graduate Theses and Dissertations
U-Pb crystallization ages of metamorphic and detrital zircons from all three paragneiss samples fall into the range of ca. 1.85-2.59 Ga, excluding two much older grains. Evidence suggests that the paragneiss of Grollier Lake record deformation exclusively from the Taltson and Trans-Hudson orogenies. It is apparent from geochronological data that the Taltson orogeny played an exceedingly larger role in the deformation of these rocks than the Trans-Hudson. Deposition of the paragneiss protoliths most likely culminated between ca. 2037-1994 Ma with metamorphism ceasing by 1852.1 ± 11.1 Ma. The oldest overgrowth considered to be concordant is 1994 ± 12 Ma and …
Evaluation Of Rusle 2 To Estimate Soil Loss From Pastures, Stasha Katrina Balkissoon
Evaluation Of Rusle 2 To Estimate Soil Loss From Pastures, Stasha Katrina Balkissoon
Graduate Theses and Dissertations
The accurate estimation of soil erosion by the Revised Universal Soil Loss Equation version 2 (RUSLE2) is critical for several conservation assessments, least of which is its use in the Phosphorus Index (PI) to identify and rank the vulnerability of agricultural fields to phosphorus (P) runoff. Earlier versions of RUSLE reported a soil loss overestimation, which were revised to give RUSLE2, where biomass production in different climatic regions was more accurately represented. RUSLE version 2.0, which contains the new vegetative biomass production routine, was evaluated using two performance indices, the Nash Sutcliffe Efficiency Index (NSE) and Index of Agreement (D) …
Characterizing The Earliest Stages Of Partial Melting: A Study Of The Pyrometamorphic Aureole Of Miocene Mt. Perkins Pluton, Northwest Arizona, Mathew Beshears
Characterizing The Earliest Stages Of Partial Melting: A Study Of The Pyrometamorphic Aureole Of Miocene Mt. Perkins Pluton, Northwest Arizona, Mathew Beshears
UNLV Theses, Dissertations, Professional Papers, and Capstones
Partial melting is an important process in the evolution of continental crust. Due to its progressive nature, evidence of the early stages of partial melting is often overprinted by later, advanced stages of partial melting. Experimental work has provided a model for the early stages of partial melting, but is limited to timescales of hours to weeks. Pyrometamorphic environments within the contact aureole of mafic intrusions provide natural laboratories for the study of the earliest stages of partial melt production on geologic time scales of 102 collected along two traverses of the tilted pyrometamorphic aureole of the Mt. Perkins pluton …
(U-Th)/He Studies Of The Southern Snake Range Metamorphic Core Complex, Nv And Gypsum Valley Salt Wall, Paradox Basin, Co, Usa, Sarah Lynn Evans
(U-Th)/He Studies Of The Southern Snake Range Metamorphic Core Complex, Nv And Gypsum Valley Salt Wall, Paradox Basin, Co, Usa, Sarah Lynn Evans
UNLV Theses, Dissertations, Professional Papers, and Capstones
This dissertation presents three studies that investigate extension in the Southern Snake Range (SSR) metamorphic core complex (MCC) of east-central Nevada and a thermal anomaly associated with the Gypsum Valley salt wall (GVSW) of southwestern Colorado. Low temperature thermochronologic studies using the (U-Th)/He system have been applied in numerous geologic settings to understand erosional and tectonic denudation processes. Two of the studies presented use (U-Th)/He thermochronology, combined with other techniques, to investigate the extensional history of the SSR and the extent of the GVSW thermal anomaly. Both of these studies present novel methods for understanding the thermal histories of the …
Effects Of Hydraulic Connections On Unsaturated Flow In Dual-Permeability Media, Jeevan Jayakody
Effects Of Hydraulic Connections On Unsaturated Flow In Dual-Permeability Media, Jeevan Jayakody
UNLV Theses, Dissertations, Professional Papers, and Capstones
A geological medium that exhibits two distinct types of flow is known as dual-permeability medium. Unconsolidated deposits composed of coarse (> 2 mm diameter) clasts (gravel, talus, rockslide debris), engineered systems (heap leach piles, capillary barriers, rock fill), and mine/construction waste fall into this category. The large inter-clast pores that are characteristic of this type of media will drain at near zero matric potentials constraining flow to the interiors of porous clasts and/or the clast surfaces. In either case, water must pass through hydraulic bridges (porous contacts and/or pendular water) that form physical connections between neighboring clasts. Therefore, properties of …
Water Balance And Moisture Dynamics Of An Arid And Semi-Arid Soil: A Weighing Lysimeter And Field Study, Jeremy E. Koonce
Water Balance And Moisture Dynamics Of An Arid And Semi-Arid Soil: A Weighing Lysimeter And Field Study, Jeremy E. Koonce
UNLV Theses, Dissertations, Professional Papers, and Capstones
Semi-arid and arid environments are characterized by low precipitation and high evapotranspiration (ET), leaving little water available for discharge into surface water bodies and groundwater recharge. For these water-limited environments, understanding the relationships between precipitation, ET, and soil moisture is critical. These relationships not only affect water resources in these increasingly populated regions but are also necessary to predict the impact of climate change on semi-arid and arid ecosystems.
The overall goal of this dissertation was to shed light on the quantitative relationships between precipitation, evaporation, ET and soil moisture dynamics in an arid and a semi-arid environment. A three-step …
11th New World Luminescence Dating Workshop Scientific Program And Abstracts And Field Trip Guide Book, P.R. Hanson, James B. Swinehart, Joseph Mason
11th New World Luminescence Dating Workshop Scientific Program And Abstracts And Field Trip Guide Book, P.R. Hanson, James B. Swinehart, Joseph Mason
Conservation and Survey Division: Faculty and Staff Publications
No abstract provided.
Establishing A Vegetative Cap For Sustainable Stabilization Of Copper Contaminated Soils In Torch Lake, Michigan, Virinder Pal Singh Sidhu
Establishing A Vegetative Cap For Sustainable Stabilization Of Copper Contaminated Soils In Torch Lake, Michigan, Virinder Pal Singh Sidhu
Theses, Dissertations and Culminating Projects
Extensive mining activities during the late 19th and early 20th centuries in the Upper Peninsula, Michigan have resulted in a number of contaminated sites with mine tailings. Several million metric tons of mine tailings were generated during the peak of copper (Cu) mining activities in this region. These tailings are called “stamp sands” because they were generated by crushing native Cu containing rocks, by a process known as stamping. The stamp sands were discharged into Lake Superior, other interior lakes and their shorelines, converting these areas into vast, fallow lands. The Cu contaminated stamp sands are being eroded back into …
Linear Trend Analysis: Implications For A Structural Fracture System And Applications Of Subsurface Fluid Migration, Northwest Arkansas And Eastern Oklahoma, Loren Labusch
Graduate Theses and Dissertations
Lineaments are mappable, simple or composite linear or curvilinear features of the Earth’s surface longer than one mile, which differ from the patterns of adjacent features and are presumed to reflect subsurface phenomenon such as faults and fractures. The usage of the term refers to the description Lattman published in 1958 and was the foundation for work by MacDonald in 1977, which is the basis for this project. Remote sensing techniques have provided a valuable means to analyze lineaments on a large scale in a relatively short time in comparison to field mapping methods. The products of such fracture studies …
Investigating Mineral Stability Under Venus Conditions: A Focus On The Venus Radar Anomalies, Erika Kohler
Investigating Mineral Stability Under Venus Conditions: A Focus On The Venus Radar Anomalies, Erika Kohler
Graduate Theses and Dissertations
Radar studies of the surface of Venus have identified regions with high radar reflectivity concentrated in the Venusian highlands: between 2.5 and 4.75 km above a planetary radius of 6051 km, though it varies with latitude. Previous research has proposed several theories on the source of these anomalies, including increased surface roughness, metallic materials with higher dielectric constants, or ferroelectric materials. Prior work suggests several processes that could be the origin of these anomalies, such as surface-atmospheric interactions or low lying clouds or fog. Alternatively, these anomalies could result from a semi-metallic compound trapped at the cooler conditions in the …
A Geochemical Analysis Of The Arkansas Novaculite And Comparison To The Siliceous Deposits Of The Boone Formation, John Byron Scott Philbrick
A Geochemical Analysis Of The Arkansas Novaculite And Comparison To The Siliceous Deposits Of The Boone Formation, John Byron Scott Philbrick
Graduate Theses and Dissertations
Geochemical analyses of the Arkansas Novaculite, located within core structures of the Ouachita Mountains in west-central Arkansas, and penecontemporaneous chert of the lower Boone Formation, located atop the Springfield Plateau of southwest Missouri, northwest Arkansas, and northeast Oklahoma, have identified a significant concentration of both aluminum and potassium. This would seem to eliminate a biogenic origin and favor a volcanic source of the silica that comprises these units. Trace and rare earth element (REE) analysis also suggests that the Arkansas Novaculite and the chert in the lower Boone Formation may have both been formed from the same volcanic source.
The …
The Mass Flux Of Non-Renewable Energy For Humanity, Edwin Dale Solomon
The Mass Flux Of Non-Renewable Energy For Humanity, Edwin Dale Solomon
Graduate Theses and Dissertations
The global energy supply relies on non-renewable energy sources, coal, crude oil, and natural gas, along with nuclear power from uranium and these finite resources are located within the upper few kilometers of the Earth’s crust. The total quantity of non-renewable energy resources consumed relative to the total quantity available is an essential question facing humanity. Analyses of energy consumption was conducted for the period 1800 – 2014 using data from the U. S. Energy Information Administration (EIA) and World Energy Production, 1800-1985 to determine the balance between non-renewable energy resources consumed and ultimately recoverable reserves. Annual energy consumption was …
Isotopic Identification Of Multiple Contributors Of Metal Ions In Mississippi Valley-Type Ore Deposits Along The Cincinnati Arch In South-Central Kentucky, William Travis Garmon
Isotopic Identification Of Multiple Contributors Of Metal Ions In Mississippi Valley-Type Ore Deposits Along The Cincinnati Arch In South-Central Kentucky, William Travis Garmon
Graduate Theses and Dissertations
Mississippi Valley-Type (MVT) ores are economically-viable deposits of sulfide minerals, often dominated by sphalerite (zinc-sulfide) in carbonate facies, and galena (lead-sulfide) in siliciclastic facies. MVT ores precipitate from migrating fluids, which carry base metals often complexed with chlorine ions within a basinal brine. This study identifies metal-contributing source-regions of the Burkesville MVT deposit using Pb-isotope ratios within sphalerite samples collected from the Burkesville deposit. The deposit is found in south-central Kentucky within the Middle-Tennessee ore district along the crest of the Cincinnati Arch, which is the anticlinal divide between the Appalachian Basin and the Illinois Basin. Competing theories argue that …
Stratigraphic Interpretation And Reservoir Implications Of The Arbuckle Group (Cambrian-Ordovician) Using 3d Seismic, Osage County, Oklahoma, Ryan Marc Keeling
Stratigraphic Interpretation And Reservoir Implications Of The Arbuckle Group (Cambrian-Ordovician) Using 3d Seismic, Osage County, Oklahoma, Ryan Marc Keeling
Graduate Theses and Dissertations
The Arbuckle Group in northeastern Oklahoma consists of multiple carbonate formations, along with several relatively thin sandstone units. The group is a part of the “Great American Carbonate Bank” of the mid-continent and can be found regionally as far east as the Arkoma Basin in Arkansas, and as far west as the Anadarko Basin in Oklahoma. The Arbuckle is part of the craton-wide Sauk sequence, which is both underlain and overlain by regional unconformities.
Arbuckle is not deposited directly on top of a source rock. In order for reservoirs within the Arbuckle to become charged with hydrocarbons, they must be …
Influences Of Channel Dredging On Avulsion Potential At The Atchafalaya River, Gordon William Mccain
Influences Of Channel Dredging On Avulsion Potential At The Atchafalaya River, Gordon William Mccain
Graduate Theses and Dissertations
In 1950, the U.S. Army Corps of Engineers (USACE) reported a rapid increase of water discharge from the Mississippi River to its distributary channel; the Atchafalaya River. If not prevented by man-made structures, the complete capture of the Mississippi River by the Atchafalaya River was predicted. The USACE report cites multiple causes for the observed increase in discharge partitioning, yet fails to assess the largescale channel dredging operations conducted throughout the Atchafalaya River Basin during the 1930's and 1940's as a potential cause for the increased discharge. To assess the role man-made interventions, specifically channel dredging, played in the increase …
Dietary Effects On The Stoichiometry Of Growth, Regulation, And Wastes Of Ozark Stream Insect Detritivores, Halvor Matthew Halvorson
Dietary Effects On The Stoichiometry Of Growth, Regulation, And Wastes Of Ozark Stream Insect Detritivores, Halvor Matthew Halvorson
Graduate Theses and Dissertations
A widespread stressor, anthropogenic nitrogen (N) and phosphorus (P) pollution can increase resource nutrient content and alter animal community composition in freshwater ecosystems. In this dissertation, I used ecological stoichiometry theory to examine effects of diet nutrient content and leaf litter type on growth, regulation, and wastes of aquatic invertebrate detritivores. I tested effects of leaf litter diet carbon:phosphorus (C:P) on growth and stoichiometric regulation of the detritivorous caddisfly Pycnopsyche lepida and used results to determine a threshold elemental ratio of oak litter C:P=1620 that confers peak growth of this species. This empirical, growth-based approach provided a more accurate estimate …
Statistical Analysis Of Fluvial Channel Belts, Kyle Ryan Spencer
Statistical Analysis Of Fluvial Channel Belts, Kyle Ryan Spencer
Graduate Theses and Dissertations
As meandering rivers laterally migrate over time, they build channel belts. The accumulation of all previous flow paths creates the channel belt. To better understand these ancient rivers, modern river systems are being mapped to find statistical relationships between current flow path and the channel belt of river systems. It is important to examine a wide range of systems in terms of age, size, and location. The rivers are being mapped using an ImageJ, interpretations from Saucier (1994) and Google Earth. Three channel belt morphologies are mapped for 15 modern channel belts; the width of the river in relation to …
Description Of Cranial Elements And Ontogenetic Change Within Tropidolaemus Wagleri (Serpentes: Crotalinae)., Nicolette L. Hill
Description Of Cranial Elements And Ontogenetic Change Within Tropidolaemus Wagleri (Serpentes: Crotalinae)., Nicolette L. Hill
Electronic Theses and Dissertations
Tropidolaemus wagleri is a species of Asian pitviper with a geographic range including Thailand, Vietnam, Malaysia, Singapore, Bruniei, parts of Indonesia, and the hilippines. Tropidolaemus is a member of the Crotalinae subfamily, within Viperidae. The genus Tropidolaemus includes five species, and was once included within the genus Trimeresurus. While some osteologic characteristics have been noted a comprehensive description of cranial elements has not been produced for T. wagleri. An in-depth description of the cranial skeleton of Tropidolaemus wagleri lays the foundation for future projects to compare and contrast other taxa within Crotalinae and Viperidae. The chosen reference specimen …
Ecological Niche Modeling Of The North American Giant Salamander: Predicting Current And Future Potential Distributions And Examining Environmental Influences, Selena S. Roark
Electronic Theses and Dissertations
North American Giant Salamanders (Cryptobranchus alleganiensis), commonly known as hellbenders, have been experiencing a population decline for decades due to human influences, such as pollution and habitat destruction. Many efforts are underway to save the hellbender but their entire potential geographical range has not been well-studied. Currently, hellbender populations are delineated by county boundaries and are on the International Union for Conservation of Nature Red List. The Genetic Algorithm for Rule-set Production, an Ecological Niche Model, was used to model the current hellbender potential distribution at a macro-scale under two different environmental scenarios. Additionally, future potential distributions were …
Modeling The Influence Of The Heterogeneous Substrate On The Transport Of The Jet Fuel Solute Plume, Kirtland Air Force Base, Albuquerque, New Mexico, Hannah Sarah Gatz-Miller
Modeling The Influence Of The Heterogeneous Substrate On The Transport Of The Jet Fuel Solute Plume, Kirtland Air Force Base, Albuquerque, New Mexico, Hannah Sarah Gatz-Miller
Earth and Planetary Sciences ETDs
A subsurface model was developed to characterize the influence of heterogeneity on solute phase plume migration of the Jet Fuel spill of Kirtland Air Force Base. Core –logs from KAFB boreholes were compiled, and lithology was interpolated across the study area using transition probability geostatistics (T-PROGS). High conductivity materials in the travel path resulted in a faster than average breakthrough time while, if low conductivity materials were placed in the travel path, particles were either forced to divert around the low K material, which added time and changed the direction of travel, or were forced by the hydraulic gradient to …
Spatial Distribution And Geomorphic Factors Of Lead Contamination On Floodplains Affected By Historical Mining, Big Rover, S.E. Missouri, David Bower Huggins
Spatial Distribution And Geomorphic Factors Of Lead Contamination On Floodplains Affected By Historical Mining, Big Rover, S.E. Missouri, David Bower Huggins
Graduate Theses/Dissertations
Historical mining in the Old Lead Belt resulted in lead (Pb) contamination of floodplain soils for over 170 km along the Big River in southeastern Missouri. The overall pattern of contamination are understood. However, Pb distribution across floodplain surfaces has not been investigated at the scale needed for site-level remediation planning. The goal of this project is to examine spatial distribution of Pb with more detail and identify the role of geomorphic processes. Predictive models are needed to evaluate factors affecting Pb distribution such as elevation, distance from the channel, and geochemistry. This study evaluates Pb distribution at three ~1km …