Open Access. Powered by Scholars. Published by Universities.®

Digital Commons Network™

Open Access. Powered by Scholars. Published by Universities.®

Earth Sciences

Institution
Keyword
Publication Year
Publication
Publication Type
File Type

Articles 11461 - 11490 of 17808

Full-Text Articles in Entire DC Network

Uptake, Metabolism, And Elimination Of Fungicides From Coated Wheat Seeds In Japanese Quail (Coturnix Japonica), Michael S. Gross, Thomas G. Bean, Michelle L. Hladik, Barnett A. Rattner, Kathryn M. Kuivila Jan 2020

Uptake, Metabolism, And Elimination Of Fungicides From Coated Wheat Seeds In Japanese Quail (Coturnix Japonica), Michael S. Gross, Thomas G. Bean, Michelle L. Hladik, Barnett A. Rattner, Kathryn M. Kuivila

United States Geological Survey: Staff Publications

Pesticides coated to the seed surface potentially pose an ecological risk to granivorous birds that consume incompletely buried or spilled seeds. To assess the toxicokinetics of seeds treated with current-use fungicides, Japanese quail ( Coturnix japonica) were orally dosed with commercially coated wheat seeds. Quail were exposed to metalaxyl, tebuconazole, and fludioxonil at either a low dose (0.0655, 0.0308, and 0.0328 mg/kg of body weight, respectively) or a high dose (0.196, 0.0925, and 0.0985 mg/kg of body weight, respectively). Fungicides were rapidly absorbed and distributed to tissues. Tebuconazole was metabolized into tert-butylhydroxy-tebuconazole. All compounds were eliminated to below detection limits …


Understanding South Dakota Farmers’ Intentions To And Adoption Of Conservation Practices: An Examination Of The Theory Of Planned Behavior, Edem Avemegah Jan 2020

Understanding South Dakota Farmers’ Intentions To And Adoption Of Conservation Practices: An Examination Of The Theory Of Planned Behavior, Edem Avemegah

Electronic Theses and Dissertations

Conservation agriculture practice is a sustainable farming method based on three principle: crop diversification, minimal soil disturbance or movement and permanent or semi-permanent of soil cover. Government and stakeholders within the agricultural sector in the United States are promoting conservation farming practices but limited voluntary adoption still exists among producers at the farm level. This research study investigated the factors that influence the adoption of conservation practices among producers in the eastern and central parts of South Dakota (SD). A modified theory of planned behavior (TPB) is used as a framework alongside socioeconomic and demographic indicators to understand farmers’ current …


Crop Rotations, Tillage And Cover Crops Influences On Soil Health, Greenhouse Gas Emissions And Farm Profitability, Jasdeep Singh Jan 2020

Crop Rotations, Tillage And Cover Crops Influences On Soil Health, Greenhouse Gas Emissions And Farm Profitability, Jasdeep Singh

Electronic Theses and Dissertations

This study assessed the effects of three levels of crop rotation: [2-yr; corn (Zea mays L.)- soybean (Glycine max L.), 3-yr; corn-soybean-oat (Avena sativa L.) or 4-yr; cornsoybean- oat-winter wheat (Triticum aestivum L.)], two tillage [conventional-till (CT) and no-till (NT)], and two winter cover cropping systems [cover crop (CC) or fallow control (NC)] on soil biochemical and physical properties, greenhouse gas emissions (GHG), microbial community composition, crop yield and farm profitability under silty clay loam soil of south eastern South Dakota. Experimental design was a randomized complete block design in a split-split plot treatment arrangement with four replications. Rotations, tillage …


Tidal-Groundwater Study Of The Slaughter Beach Salt Marsh In Slaughter Beach, De, Michael Powers Jan 2020

Tidal-Groundwater Study Of The Slaughter Beach Salt Marsh In Slaughter Beach, De, Michael Powers

West Chester University Master’s Theses

Seasonal and decadal monitoring of salt marsh at Slaughter Beach, DE documented long-term and short-term variations in number and sizes of salt ponds. Over 400 salt ponds ranging in size between 0.5 m2 to 0.11 km2 were identified on 5.5 km2 salt marsh platform. The purpose of this study is to quantify hydrologic conditions and measure groundwater discharge of a salt marsh, particularly the impact of tidal forces on groundwater fluctuation.

Four wells with nests of mini-piezometers with ONSET Pressure Transducers were installed along a transect crossing the largest salt pond (0.11 km2) in the …


Paleofloods And Landform Development Influence Carbon Storage In A Humid-Subtropical River Valley, Christopher Lance Stewart Jan 2020

Paleofloods And Landform Development Influence Carbon Storage In A Humid-Subtropical River Valley, Christopher Lance Stewart

Murray State Theses and Dissertations

Floodplains can store large amounts of soil organic carbon (SOC) despite covering a small fraction of the global land area. Since these valley-bottom landforms build through the action of flooding, the century to millennial-scale record of overbank deposition could be important in understanding controls on deep (>30 cm) SOC storage. Yet, the influence of flood history and landform development on carbon content is surprisingly not well known. I use a combined geological and pedological approach to characterize the sedimentation, soil development, and SOC of fluvial terraces along an impounded reach of the humid-subtropical Tennessee River valley, U.S.A. The standardized …


Soil Physical And Hydrological Properties, And Greenhouse Gas Emissions Under Integrated Crop-Livestock Agroecosystems, Navdeep Singh Jan 2020

Soil Physical And Hydrological Properties, And Greenhouse Gas Emissions Under Integrated Crop-Livestock Agroecosystems, Navdeep Singh

Electronic Theses and Dissertations

Cover crops (CCs) and grazing play a critical role in successful implementation of the integrated crop-livestock system (ICLS) because they can have a direct impact on soils and greenhouse gas emissions. The objectives of this study were to (i) evaluate the short-term impacts of CCs [grass dominated cover crops (GdC) and legume dominated cover crops (LdC)] and grazed CCs and corn (Zea mays L.) residue under oat (Avena sativa L.)–CC–corn rotation on soil physical and hydrological properties; (ii) quantify the architecture of soil pores using X-ray computed tomography (CT) for soils managed under long-term ICLS, native grazed pasture and corn-soybean …


Isotopic And Geochemical Tracers Of Groundwater Flow In The Shivwits Plateau, Grand Canyon National Park, Jonathan W. Wilson Jan 2020

Isotopic And Geochemical Tracers Of Groundwater Flow In The Shivwits Plateau, Grand Canyon National Park, Jonathan W. Wilson

Theses and Dissertations--Earth and Environmental Sciences

As the impacts of global climate change on water resources continue to become more apparent, proper understanding and management of groundwater resources will be needed as supplies become more strained. Traditional methods of characterizing groundwater systems are time-intensive, costly, and can be difficult to complete in remote areas. Using ambient geochemical tracers from discrete sampling could aid in characterizing spring systems through determining flow paths, recharge areas, and carbon cycling. However, using discrete seasonal samples to understand the hydrogeology of complex, mixed-lithology aquifers has not been extensively examined. Here we explore using δ13C of dissolved organic carbon (DOC), …


Stable Carbon And Oxygen Isotopes As Environmental Indicators Of The Late Pleistocene Inel Arenoso, Sonora, Northwest Mexico, Victor Adrian Perez Crespo, Tamara Cruz Y Cruz, Alejandro Terrazas Mata, Pedro Morales Puente, Martha Benavente, Edith Cienfuegos-Alvrado, Francisco J. Otero Jan 2020

Stable Carbon And Oxygen Isotopes As Environmental Indicators Of The Late Pleistocene Inel Arenoso, Sonora, Northwest Mexico, Victor Adrian Perez Crespo, Tamara Cruz Y Cruz, Alejandro Terrazas Mata, Pedro Morales Puente, Martha Benavente, Edith Cienfuegos-Alvrado, Francisco J. Otero

Turkish Journal of Earth Sciences

The paleoenvironment conditions that existed in the Late Pleistocene at the archaeological-paleontological site of El Arenoso, Sonora, NW Mexico, were inferred using the carbon and oxygen stable isotopes from one bison, one mammoth, and thirteen horses as well as the pedological characteristics and the carbon isotopes of calcium carbonates from paleosoil. The values δ13C of the bison (-1.4‰), the horses (-2.8‰), and the mammoth (-4.3‰) show that these animals fed mainly on C4 plants and carbon isotopic values from profile horizons of locality 4Bgk (-3.4‰), 3Ck (-3.4‰), and 2Bgk2 (-5.7‰) indicated the presence of C3/C4 vegetation mixed in El Arenoso. …


Paleoecological Insights On Latest Oligocene-Early Miocene Planktonic Foraminifera From The J-Anomaly Ridge (Iodp Hole U1406a), Alessio Fabbrini, Luca Maria Foresi Jan 2020

Paleoecological Insights On Latest Oligocene-Early Miocene Planktonic Foraminifera From The J-Anomaly Ridge (Iodp Hole U1406a), Alessio Fabbrini, Luca Maria Foresi

Turkish Journal of Earth Sciences

This paper focuses on a paleoecological study conducted on planktonic foraminifera from upper Oligocene-lower Miocene deposits of the J-Anomaly Ridge (North Atlantic Ocean). Paleoclimatic studies are crucial to better comprehend how climatic changes occurred in the past and how they might influence global climate in the next few decades. Oceanic currents are the predominant vehicle for heat transport across the globe and therefore organisms living within the water mass can supply much information on paleoceanographic settings. In total, 53 samples from IODP Hole U1406A were selected in the core interval 96-24 CCSF-M to perform statistical analyses (R-mode cluster analysis, principal …


Determining The Lake Protected Zones Using Gis-Based Drastic Model To Groundwatervulnerability In Salda Lake Basin (Burdur/Turkey), Si̇mge Varol, Ayşen Davraz, Erhan Şener, Şehnaz Şener, Fatma Aksever, Bülent Kirkan, Ahmet Tokgözlü Jan 2020

Determining The Lake Protected Zones Using Gis-Based Drastic Model To Groundwatervulnerability In Salda Lake Basin (Burdur/Turkey), Si̇mge Varol, Ayşen Davraz, Erhan Şener, Şehnaz Şener, Fatma Aksever, Bülent Kirkan, Ahmet Tokgözlü

Turkish Journal of Earth Sciences

Groundwater quality is a crucial parameter for sustainable wetland management. The evaluation of the aquifer vulnerability is important for the protection of groundwater resources. The DRASTIC model is the most significant technique for the assessment of aquifer vulnerability. This study aimed to build a vulnerability map for groundwater of the Salda Lake wetland basin by DRASTIC method in a GIS environment. Seven environmental parameters (depth to water table, net recharge, aquifer media, soil media, topography, impact of the vadose zone media, and hydraulic conductivity of the aquifer) were used in the DRASTIC method and GIS was used to constitute a …


Daily Variations In Stratification In İzmit Bay, Hüsne Altiok, Lalehan Can, Sabri̇ Mutlu Jan 2020

Daily Variations In Stratification In İzmit Bay, Hüsne Altiok, Lalehan Can, Sabri̇ Mutlu

Turkish Journal of Earth Sciences

We studied the diurnal variation of stratification in İzmit Bay with temperature and current velocity, and investigated the influence of atmospheric conditions. In the east of the bay entrance, 10-min temperature and hourly current measurements were made between the dates of 4 February 2015 and 24 April 2015, down to about 40 m depth in the water column. In addition to this, hourly temperature and salinity with depth data were collected between the dates of 4 and 7 February 2015 by a research vessel. The meteorological parameters for the atmospheric conditions were obtained from the closest weather stations (Yalova, Çınarcık, …


Heavy Metal Contamination In Groundwater And Surface Water Due To Active Pb-Zn-Cumine Tails And Water-Rock Interactions: A Case Study From The Küre Mine Area (Turkey), Tülay Ekemen Keski̇n, Emre Özler Jan 2020

Heavy Metal Contamination In Groundwater And Surface Water Due To Active Pb-Zn-Cumine Tails And Water-Rock Interactions: A Case Study From The Küre Mine Area (Turkey), Tülay Ekemen Keski̇n, Emre Özler

Turkish Journal of Earth Sciences

This study aimed at elucidating the groundwater and surface water pollution resulting from water-rock interaction, mine tailings, and mining activities at Küre (Kastamonu) sulfidic Pb-Zn-Cu mine area and its vicinity. The study area has a surface area of approximately 2990 km2. The Küre River drainage site covering the study area is approximately 440 km2. The concentrations of SO4, Al, As, Ba, Mn, Ni, Sb, and Pb in some groundwater (K10, K20, K21, K27, K28, K29, K30), and surface water (KR3) exceed the maximum limit values with respect to the Turkish Standards for Water Intended For Human Consumption and World Health …


New Geosite Candidates From Urla (İzmir, Western Anatolia, Turkey): A List Of Geologicalassets Nested With Antique And Modern Cultural Heritage, Ökmen Sümer, Mehmet Akbulut, Hülya İnaner Jan 2020

New Geosite Candidates From Urla (İzmir, Western Anatolia, Turkey): A List Of Geologicalassets Nested With Antique And Modern Cultural Heritage, Ökmen Sümer, Mehmet Akbulut, Hülya İnaner

Turkish Journal of Earth Sciences

The Urla Basin is an approximately 20 km wide and 30 km long N-S-trending strike-slip basin, located in the westernmost part of the Western Anatolia Extensional Province. Although the basin-fill units are generally composed of sedimentary and volcanic rocks of Miocene to Recent, Triassic and Late Cretaceous-Paleocene sedimentary rocks are also exposed in the middle and western part of the basin. In addition to this geological diversity, the basin hosts many ancient settlements due to its geographical position and close contact with the Aegean Sea. This study mostly focuses on the northern part of the basin with a concentration on …


Estimating Abiotic Thresholds For Sagebrush Condition Class In The Western United States, Stephen Boyte, Bruce K. Wylie, Yingxin Gu, Donald J. Major Jan 2020

Estimating Abiotic Thresholds For Sagebrush Condition Class In The Western United States, Stephen Boyte, Bruce K. Wylie, Yingxin Gu, Donald J. Major

United States Geological Survey: Staff Publications

Sagebrush ecosystems of the western United States can transition from extended periods of relatively stable conditions to rapid ecological change if acute disturbances occur. Areas dominated by native sagebrush can transition from species-rich native systems to altered states where non-native annual grasses dominate, if resistance to annual grasses is low. The non-native annual grasses provide relatively little value to wildlife, livestock, and humans and function as fuel that increases fire frequency. The more land area covered by annual grasses, the higher the potential for fire, thus reducing the potential for native vegetation to reestablish, even when applying restoration treatments. Mapping …


Phytoremediation Of Saline-Sodic Soils In East Central South Dakota Utilizing Perennial Grass Mixtures, Douglas J. Fiedler Jan 2020

Phytoremediation Of Saline-Sodic Soils In East Central South Dakota Utilizing Perennial Grass Mixtures, Douglas J. Fiedler

Electronic Theses and Dissertations

Several decades of above average precipitation in South Dakota has increased the area of saline and sodic soils, which reduce crop yields and inhibit sensitive plant growth. Saline and sodic soils are difficult to remediate using traditional agricultural crops. Establishing salt tolerant perennial species may restore productivity to salt affected areas. Two perennial grass mixtures (mix 1: slender wheatgrass, beardless wildrye; mix 2: slender wheatgrass, western wheatgrass, green wheatgrass, creeping meadow foxtail) were dormant frost seeded along a topographic gradient in Clark Co., SD. Soils were Forman-Cresbard loam and a Cresbard-Cavour loam with surface electrical conductivity (EC1:1) that …


Lake Or Estuary? Sedimentary And Benthic Foraminiferal Characterization Of A Gulf Of Mexico Coastal Dune Lake, Kaylyn C. Bellais, Samuel T. Barber, Donald A. Beebe, Murlene W. Clark Jan 2020

Lake Or Estuary? Sedimentary And Benthic Foraminiferal Characterization Of A Gulf Of Mexico Coastal Dune Lake, Kaylyn C. Bellais, Samuel T. Barber, Donald A. Beebe, Murlene W. Clark

Gulf and Caribbean Research

Coastal dune lakes are shallow estuaries located within dune environments that share a permanent or intermittent connection with the sea. Because coastal dune lakes are found in few locations worldwide (e.g. Australia, New Zealand, Florida, etc.) they represent unique environments worthy of protection. However; there is a distinct lack of scientific data related to the function and ecology of coastal dune lakes, especially in the Gulf of Mexico. Therefore, the purpose of this study was to characterize the sedimentology and foraminifera of a representative coastal dune lake in Walton County, FL (i.e. Eastern Lake) and determine whether it shares geologic …


Aquatic Plants And Their Application To Successful Floating Treatment Wetlands, Katherine May Mazanec Jan 2020

Aquatic Plants And Their Application To Successful Floating Treatment Wetlands, Katherine May Mazanec

Masters Theses

“This research aims to mitigate eutrophication of freshwater habitats affected by urban stormwater runoff. Two highly impacted urban ponds near the Missouri S&T campus in Rolla were the focus of this research on the application of floating treatment wetlands (FTWs). An FTW consists of a man-made floating mat that is planted with emergent or floating macrophytes. The plants grow on the mat and their roots extend into the water column below the mat. Plant tissues, especially roots in direct contact with the water, take up nutrients, act as biofilm growth sites, and may facilitate precipitation of nutrients. With urbanization, ponds …


Mariana Serpentinite Mud Volcanism Exhumes Subducted Seamount Materials: Implications For The Origin Of Life, Patricia Freyer, C. G. Wheat, Trevor Williams, Christopher Kelley, Kevin Johnson, Jeffrey Ryan, Walter Kurz, John Shervais, Elmar Albers, Barbara Bekins Jan 2020

Mariana Serpentinite Mud Volcanism Exhumes Subducted Seamount Materials: Implications For The Origin Of Life, Patricia Freyer, C. G. Wheat, Trevor Williams, Christopher Kelley, Kevin Johnson, Jeffrey Ryan, Walter Kurz, John Shervais, Elmar Albers, Barbara Bekins

School of Geosciences Faculty and Staff Publications

The subduction of seamounts and ridge features at convergent plate boundaries plays an important role in the deformation of the overriding plate and influences geochemical cycling and associated biological processes. Active serpentinization of forearc mantle and serpentinite mud volcanism on the Mariana forearc (between the trench and active volcanic arc) provides windows on subduction processes.  Here, we present (1) the first observation of an extensive exposure of an undeformed Cretaceous seamount currently being subducted at the Mariana Trench inner slope; (2) vertical deformation of the forearc region related to subduction of Pacific Plate seamounts and thickened crust; (3) recovered Ocean …


Scientist Of The Week!, Sarah L. Sheffield, Lisette Melendez, Kristin Houdyshell, Mathew Burgos Jan 2020

Scientist Of The Week!, Sarah L. Sheffield, Lisette Melendez, Kristin Houdyshell, Mathew Burgos

School of Geosciences Faculty and Staff Publications

No abstract provided.


Boosting Computational Effectiveness In Big Spatial Flow Data Analysis With Intelligent Data Reduction, Ran Tao, Zhaoya Gong, Qiwei Ma, Jean-Claude Thill Jan 2020

Boosting Computational Effectiveness In Big Spatial Flow Data Analysis With Intelligent Data Reduction, Ran Tao, Zhaoya Gong, Qiwei Ma, Jean-Claude Thill

School of Geosciences Faculty and Staff Publications

One of the enduring issues of spatial origin-destination (OD) flow data analysis is the computational inefficiency or even the impossibility to handle large datasets. Despite the recent advancements in high performance computing (HPC) and the ready availability of powerful computing infrastructure, we argue that the best solutions are based on a thorough understanding of the fundamental properties of the data. This paper focuses on overcoming the computational challenge through data reduction that intelligently takes advantage of the heavy-tailed distributional property of most flow datasets. We specifically propose the classification technique of head/tail breaks to this end. We test this approach …


Estimating Dispersal And Evolutionary Dynamics In Diploporan Blastozoans (Echinodermata) Across The Great Ordovician Biodiversification Event, Adriane R. Lam, Sarah L. Sheffield, Nicholas J. Matzke Jan 2020

Estimating Dispersal And Evolutionary Dynamics In Diploporan Blastozoans (Echinodermata) Across The Great Ordovician Biodiversification Event, Adriane R. Lam, Sarah L. Sheffield, Nicholas J. Matzke

School of Geosciences Faculty and Staff Publications

Echinoderms make up a substantial component of Ordovician marine invertebrates, yet their speciation and dispersal history as inferred within a rigorous phylogenetic and statistical framework is lacking. We use biogeographic stochastic mapping (BSM; implemented in the R package BioGeoBEARS) to infer ancestral area relationships and the number and type of dispersal events through the Ordovician for diploporan blastozoans and related species. The BSM analysis was divided into three time slices to analyze how dispersal paths changed before and during the great Ordovician biodiversification event (GOBE) and within the Late Ordovician mass extinction intervals. The best-fit biogeographic model incorporated jump dispersal, …


Uncovering Host-Microbiome Interactions In Global Systems With Collaborative Programming: A Novel Approach Integrating Social And Data Sciences [Version 1; Peer Review: Awaiting Peer Review], Jenna Oberstaller, Swamy Rakesh Adapa, Guy Dayhoff Ii, Justin Gibbons, Gregory S. Herbert Jan 2020

Uncovering Host-Microbiome Interactions In Global Systems With Collaborative Programming: A Novel Approach Integrating Social And Data Sciences [Version 1; Peer Review: Awaiting Peer Review], Jenna Oberstaller, Swamy Rakesh Adapa, Guy Dayhoff Ii, Justin Gibbons, Gregory S. Herbert

School of Geosciences Faculty and Staff Publications

Microbiome data are undergoing exponential growth powered by rapid technological advancement. As the scope and depth of microbiome research increases, cross-disciplinary research is urgently needed for interpreting and harnessing the unprecedented data output. However, conventional research settings pose challenges to much-needed interdisciplinary research efforts due to barriers in scientific terminologies, methodology and research-culture. To breach these barriers, our University of South Florida OneHealth Codeathon was designed to be an interactive, hands-on event that solves real-world data problems. The format brought together students, postdocs, faculty, researchers, and clinicians in a uniquely cross-disciplinary, team-focused setting. Teams were formed to encourage equitable distribution …


F2.3 Seasonal Freshwater Lakes, R. T. Kingsford, R. Mac Nally, Mark C. Rains, B. J. Robson, K. Irvine, D. A. Keith Jan 2020

F2.3 Seasonal Freshwater Lakes, R. T. Kingsford, R. Mac Nally, Mark C. Rains, B. J. Robson, K. Irvine, D. A. Keith

School of Geosciences Faculty and Staff Publications

No abstract provided.


F1.1 Permanent Upland Streams, R. T. Kingsford, R. Mac Nally, P. S. Giller, Mark C. Rains, M. Kelly-Quinn, A. H. Arthington, D. A. Keith Jan 2020

F1.1 Permanent Upland Streams, R. T. Kingsford, R. Mac Nally, P. S. Giller, Mark C. Rains, M. Kelly-Quinn, A. H. Arthington, D. A. Keith

School of Geosciences Faculty and Staff Publications

No abstract provided.


Serpentinization As A Route To Liberating Phosphorus On Habitable Worlds, Matthew Pasek, Arthur Omran, Carolyn Lang, Maheen Gull, Josh Abbatiello, Tian Feng, Lyle Garong, Heather Abbott-Lyon Jan 2020

Serpentinization As A Route To Liberating Phosphorus On Habitable Worlds, Matthew Pasek, Arthur Omran, Carolyn Lang, Maheen Gull, Josh Abbatiello, Tian Feng, Lyle Garong, Heather Abbott-Lyon

School of Geosciences Faculty and Staff Publications

Planetary habitability is in part governed by nutrient availability, including the availability of the element phosphorus. The nutrient phosphorus plays roles in various necessary biochemical functions, and its biogeochemical cycling has been proposed to be extremely slow due to a strong coupling to the rock cycle via mineral weathering. Here we show a route to P liberation from water-rock reactions that are thought to be common throughout the Solar System. We report the speciation of phosphorus in serpentinite rocks to include the ion phosphite (HPO32- with P3+) and show that reduction of phosphate to phosphite is predicted from thermodynamic models …


An Assessment Of Convergence In The Feeding Morphology Of Xiphactinus Audax And Megalops Atlanticus Using Landmark-Based Geometric Morphometrics, Edward Chase Shelburne Jan 2020

An Assessment Of Convergence In The Feeding Morphology Of Xiphactinus Audax And Megalops Atlanticus Using Landmark-Based Geometric Morphometrics, Edward Chase Shelburne

Master's Theses or Doctor of Nursing Practice

Convergence is an evolutionary phenomenon wherein distantly related organisms independently develop features or functional adaptations to overcome similar environmental constraints. Historically, convergence among organisms has been speculated or asserted with little rigorous or quantitative investigation. More recent advancements in systematics has allowed for the detection and study of convergence in a phylogenetic context, but this does little to elucidate convergent anatomical features in extinct taxa with poorly understood evolutionary histories. The purpose of this study is to investigate one potentially convergent system—the feeding structure of Xiphactinus audax (Teleostei: Ichthyodectiformes) and Megalops atlanticus (Teleostei: Elopiformes)—using a comparative anatomical approach to assess …


Microdialysis: A Method For Quantifying In Situ Nitrogen Fluxes In Soil Microsites, Srusti Maddala, Mary C. Savin, Julie A. Stenken, Lisa S. Wood Jan 2020

Microdialysis: A Method For Quantifying In Situ Nitrogen Fluxes In Soil Microsites, Srusti Maddala, Mary C. Savin, Julie A. Stenken, Lisa S. Wood

Discovery, The Student Journal of Dale Bumpers College of Agricultural, Food and Life Sciences

Microdialysis, a diffusion-based sampling technique commonly used in biomedical research, has recently been recognized as a candidate for monitoring chemical changes in the rhizosphere. The information it provides about nutrient diffusion may improve nitrogen use efficiency, leading to enhanced management and success of restoration projects. The objective of this study was to determine the efficacy of microdialysis sampling to quantify the relative recoveries (RR%) of nitrate-N and ammonium-N, the two inorganic nitrogen compounds typically found in soil. The effects of microdialysis flow rate, sample medium concentration, and the presence of both analytes in solution on the relative recoveries obtained from …


An Expanded Stratigraphic Record Of The Devonian-Carboniferous Boundary Hangenberg Biogeochemical Event From Southeast Iowa (U.S.A.), Brittany M. Stolfus, Bradley D. Cramer, Ryan J. Clark, Nicholas J. Hogancamp, James E. Day, Stephanie A. Tassier-Surine, Brian J. Witzke Jan 2020

An Expanded Stratigraphic Record Of The Devonian-Carboniferous Boundary Hangenberg Biogeochemical Event From Southeast Iowa (U.S.A.), Brittany M. Stolfus, Bradley D. Cramer, Ryan J. Clark, Nicholas J. Hogancamp, James E. Day, Stephanie A. Tassier-Surine, Brian J. Witzke

Faculty Publications - Geography, Geology, and the Environment

The Devonian-Carboniferous boundary in the type area of the Mississippian subsystem (tri-state area of Iowa, Illinois, and Missouri) has been historically difficult to identify. Many of the localities contain similar lithologies and stratigraphic successions, but chronostratigraphic correlation of seemingly identical lithologies can vary greatly in this interval and frequently this has led to miscorrelation. In particular, the similar lithofacies that comprise the McCraney Formation and Louisiana Formation have been a source of stratigraphic confusion for over 100 years. To investigate the Devonian-Carboniferous boundary interval in the Mississippian type area we selected two localities in southeastern Iowa, the H-28 core from …


A Multi-Method Investigation Of The Modern Sedimentation And Late Holocene Paleolimnology Of June Lake (Mono County, Ca), And A Survey-Based Analysis Of Ninth Graders’ Attitudes Towards Geology, Eva Lyon Jan 2020

A Multi-Method Investigation Of The Modern Sedimentation And Late Holocene Paleolimnology Of June Lake (Mono County, Ca), And A Survey-Based Analysis Of Ninth Graders’ Attitudes Towards Geology, Eva Lyon

Theses and Dissertations--Earth and Environmental Sciences

Three distinct manuscripts comprise this dissertation. The first analyzes the modern sedimentary basin of June Lake, a small glacial lake in the eastern Sierra Nevada of California (USA) using a number of data sets, including bathymetry, surface sediment composition, and seismic stratigraphy. The seismic survey revealed sublacustrine morphological features that suggest the basin originated due to ice scour, as well as four acoustically distinct stratigraphic units that reflect the history of sedimentation following glacial scouring. Corroborating the seismic record, sediment cores from the youngest unit are composed of hemipelagically deposited, organic-rich, laminated diatomaceous oozes alternating with coarse tephra beds. The …


Biogeomorphology Of Bedrock Fluvial Systems: Example From Shawnee Run, Kentucky, Usa, Tasnuba Jerin Jan 2020

Biogeomorphology Of Bedrock Fluvial Systems: Example From Shawnee Run, Kentucky, Usa, Tasnuba Jerin

Theses and Dissertations--Geography

The dynamic interactions between fluvial processes and vegetation vary in different environments and are uncertain in bedrock settings. Bedrock streams are much less studied than alluvial in all aspects, and in many respects act in qualitatively different ways. This research seeks to fill this lacuna by studying bedrock streams from a biogeomorphic perspective. The first part of this research aims to identify the impacts of woody vegetation that may be common to fluvial systems and rocky hillslopes in general, or that may be unique to bedrock channels. A review of the existing literature on biogeomorphology — mostly fluvial and rocky …