Digital Commons Network^™

Development And Evaluation Of An Automated Tactical Tillage Tool To Control Weeds In Row-Crop Production Systems, Grace Mccormick Friday

Theses and Dissertations

Weed control is an integral part of a successful overall production strategy in row- cropping systems and has the potential to reduce or eliminate yield losses that negatively affect profitability. Timely and correctly selected herbicide applications are the major keys for effective weed control in a majority of instances. However, there are negative factors that contribute to ineffectiveness and weed escape issues that currently lack viable options for management. Sparsely populated late-season weeds that emerge after lay-by herbicide applications and weeds that have become tolerant and resistant to traditional herbicide chemistries are of greatest concern. Historically, these weeds would have …

Evaluating The Relationship Between Methane Seeps And Seafloor Geomorphology On The Northern Us Atlantic Margin, Gabriel Hernandez

Theses and Dissertations

Methane seeps are a transport pathway for carbon from seafloor sediments to the marine environment with important implications for global biogeochemical cycling. Accordingly, there is substantial interest in better understanding the processes that control seep location and predicting the distribution of seeps with existing seafloor datasets. Visual evaluation of methane seeps, in multibeam sonar water column data, suggests a spatial relationship between seeps and specific seafloor morphologic features such as ridge crests. In this thesis, seafloor geomorphology at 1996 seep detection sites on the US Atlantic margin was quantitatively characterized by geomorphologic phonotype, bathymetric position index, slope, rugosity, and aspect …

Rapidly Changing Range Limits In A Warming World: Critical Data Limitations And Knowledge Gaps For Advancing Understanding Of Mangrove Range Dynamics In The Southeastern Usa, Rémi Bardou, Michael J. Osland, Steven Scyphers, Christine Shepard, Karen E. Aerni, Jahson B. Alemu I, Robert Crimian, Richard H. Day, Nicholas M. Enwright, Christopher A. Gabler

School of Earth, Environmental, & Marine Sciences Faculty Publications

Climate change is altering species’ range limits and transforming ecosystems. For example, warming temperatures are leading to the range expansion of tropical, cold-sensitive species at the expense of their cold-tolerant counterparts. In some temperate and subtropical coastal wetlands, warming winters are enabling mangrove forest encroachment into salt marsh, which is a major regime shift that has significant ecological and societal ramifications. Here, we synthesized existing data and expert knowledge to assess the distribution of mangroves near rapidly changing range limits in the southeastern USA. We used expert elicitation to identify data limitations and highlight knowledge gaps for advancing understanding of …

Small Community Water Systems Have The Highest Prevalence Of Mn In Drinking Water In California, Usa, Miranda Aiken, Samantha C. Ying

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Manganese (Mn) is currently regulated as a secondary contaminant in California, USA; however, recent revisions of the World Health Organization drinking water guidelines have increased regulatory attention of Mn in drinking water due to increasing reports of neurotoxic effects in infants and children. In this study, Mn concentrations reported to California’s Safe Drinking Water Information System were used to estimate the potentially exposed population within California based on system size. We estimate that between 2011 and 2021, over 525,000 users in areas with reported Mn data are potentially exposed to Mn concentrations exceeding the WHO health-based guideline (80 μg L …

Paleotemperature Estimates From Diatom Morphometrics In The Amundsen Sea For Marine Isotope Stage 5, Cesar Lopez

Honors Capstones

Because of ever rising temperatures driven by anthropogenic climate change, much attention has been given to the West Antarctic Ice Sheet (WAIS) by the scientific community. This is due to its sensitivity to global climate change and vulnerability for collapse as evidenced by Pleistocene interglacial events. Paleotemperature estimates from the Amundsen Sea are crucial for understanding how global temperature changes impacted WAIS throughout the Pleistocene. Marine Isotope Stage 5 (MIS 5) is of particular interest as it contains different substages and intervals of fluctuating temperatures. This period also is estimated to have had temperatures equal to, or slightly higher than …

The Dynamics Of Sedimentary Chlorophyll Α At A High-Energy Beach, Sarah (Gray) Abel

Honors Theses

Productive sandy beaches are one of the most crucial areas serving our ecosystem today. While often overlooked in scientific research, productive beaches have many essential functions that lead to the preservation and protection of many different species as well as ecological wellness and stability. A key factor that is linked to this productivity is the presence of chlorophyll in the sediments. Piston cores of the sediments at the low-tide mark at Waties Island, South Carolina, were collected across multiple years and subsequently analyzed for chlorophyll concentrations through fluorometry after acetone extraction and acidification. Each core profile was processed to calculate …

Improvements To Isru For Rocket Fuel Generation, Justin Sharp

James Madison Undergraduate Research Journal (JMURJ)

The development of efficient in-situ resource utilization (ISRU) technologies is crucial for the establishment of an extraterrestrial, self-sustaining colony. The generation of rocket fuel at potential colony locations is necessary to provide the transportation of people and cargo to and from these locations.Three processes are discussed for the improvement of ISRU methods to generate rocket fuel: electrolysis and electrochemical improvements to the process of crude fuel production, physical and chemical methods for separation of gaseous H2 and O2, and materials and cryogenics engineering for storage and transportation of liquid hydrogen (LH2) and liquid oxygen (LOX). Storage and transportation of cryogenics …

Downstream Hydrochemistry And Irrigation Water Quality Of The Syr Darya, Aral Sea Basin, South Kazakhstan, Bagdat Satybaldiyev, Baimurat Ismailov, Nurbek Nurpeisov, Kairat Kenges, Daniel D. Snow, Arindam Malakar, Omirzhan Taukebayev, Bolat Uralbekov

Daugherty Water for Food Global Institute: Faculty Publications

New hydrochemical measurements from the Syr Darya provide insights into factors affecting the composition and quality of a major freshwater source replenishing the Aral Sea. This river is heavily used for power and irrigation and crosses territories of four Central Asia republics. It is intensely managed, draining several major tributaries, many reservoirs, and numerous irrigation distribution systems and canals. Analysis of seasonal changes in dissolved ion concentrations using geochemical diagrams, elemental ratios, statistical correlation, and equilibrium modeling allowed the characterization of mineral formation processes that control the dissolved chemical composition. Measured water hydrochemistry and composition type differs substantially from previous …

Hymenachne Amplexicaluis [(Rudge) Nees] Genetic Resources Collection In México, A Suitable Grass For Flood Plains In Tropical Areas, J. F. Enriquez-Quiroz, A. R. Quero-Carrillo, J. Perez-Perez, A. Hernandez-Garay, E. Garcia-Moya

IGC Proceedings (1977-2023)

Hymenachne amplexicaluis [( Rudge ) Nees; 2n= 2x= 24; Azuche, West Indian marsh grass] is a native Central and South America C₃ grass that grows well under intermittent flooding conditions. It produces good seed set and stolons to thrive on new areas assuring its survival, combined with an efficient N metabolism to promote vigorous new growing leaves and tillers (Antel et al., 1998). Azuche is a dual attribute species when introduced to new areas; it has valuable forage attributes but also is a potential weed (Hill, 2000). As Azuche is a native species, one must deal with in …

Critical Analysis Of Tropical Forage Breeding In Brazil, J. A. Usberti Jr., P. B. Alcantara

IGC Proceedings (1977-2023)

Forage grasses account for 90% of the Brazilian forage seed market while the genera Brachiaria, Panicum and others are responsible for 85, 10 and 5% of the traded grass seeds, respectively. Most of the forage grass and legume cultivars available for sowing in Brazil were selected in germplasm banks during the last 20 years, while few of them were derived from artificial crossings, followed by selection for desirable forage traits. The selection of new genetic materials in germplasm banks (exploitation of naturally-occurring genetic variability) is still feasible but the chances of success are decreasing through time. From now on, …

New Insights Into The Paleovegetation Of The Ancient Underwater Forest Located In The Northern Gulf Of Mexico, Karla Lizarraga Garcia

Master's Theses

A well-preserved remnant of an ancient bald cypress forest (hereafter, Underwater Forest) constitutes the only known archive of a glacial refuge on the once exposed continental shelf of the Northern Gulf of Mexico. This forest existed around 41-72 yBP (MIS 3-5) according to the existing dating methods applied on previous studies. As the climate conditions and sea levels changed, the vegetation of this glacial refuge shifted from bald cypress forests to open marshes, altering the vegetation dynamics. The present research analyzed four new cores (21DF-5A, 21DF-5B, 15DF-6, and 16DF-3A), which provided additional insights into the vegetation that once existed in …

Evaluation Of Hydrogeochemical Characteristics Of San Joaquin, Tulare, And Mojave Aquifers, Southern California, Maedeh Hassanvand

Graduate Theses and Dissertations

Before making attempts to enhance and manage the quality of water, a thorough understanding of these processes is necessary since the chemical quality of groundwater is impacted by a number of linked processes. This would be more important in arid and semiarid regions like the southern part of California where more rely on groundwater for agriculture and drinking water uses than the other states. As a result, fundamental knowledge of the governing processes of groundwater chemistry is required for effective water resource management. Thus, this study is primarily concerned with three aspects in Mojave, Tulare, and San Joaquin aquifers: The …

Investigation Of Microplastics In River Bottom Sediment Along The Musconetcong River, Nicole Perkins

Theses, Dissertations and Culminating Projects

The knowledge of microplastics remains limited since there are scientific challenges in understanding long-term effects and health risks associated with microplastics in all environments. Challenges associated with microplastics investigations include limited approaches to microplastics sampling and analyses, understanding long‐term behavior of microplastics, the organismal and ecosystem health risks, and finding alternatives to using plastic. The research on microplastics has focused mainly on microplastics abundance and distribution in the environment, while their transport and pathways have remained rather understudied. The goal of this study was to expand our knowledge of microplastics in river sediment.

This microplastics investigation consisted of sampling the …

A Glimpse Into The Climate, Seasonality, Hydrological Cycle, Carbonate Chemistry And Marine Ecosystem Shift Of The Pre-Petm And The Petm Using Ncar Cesm1.2, Jiayi Wang

Earth & Environmental Sciences Dissertations - Archive

The Paleocene-Eocene Thermal Maximum (PETM, ~56 my ago, 170,000y event) is characterized by a negative δ13C excursion into the atmosphere. This event caused global temperature to increase by about 5-6 °C, followed by climate responses such as marine acidification, ocean stratification, shoaling of calcite compensation depth (CCD), stronger hydrological cycle, and significant changes in marine ecosystems. It is one of the very few analogies of today’s global warming climate and thus is valuable to study. It still holds much potential for research, including using the state-of-the-art model CESM1.2. Proxy records are limited due to the nature of geological preservation and …

Seasonal Variations In Nutrient And Total Suspended Solids Sources And Fluxes In Rivers Of Northern New Jersey And Newark Bay, Usa, Jing Nie

Theses, Dissertations and Culminating Projects

In recent decades, aquatic systems have experienced major problems with water quality due to high nutrient concentrations from both point and non-point sources resulting from industrialization, urbanization, and population growth. While nutrient pollution due to land use change cannot be ignored, point sources such as combined sewer overflows and discharging sites have also contributed to the problem. Integrated hydrodynamic, chemical, and biological models have been developed to simulate nutrient transportation from both sources. This paper reviews and analyzes water quality data from published literature to evaluate nutrient pollution in aquatic systems and emphasizes the need for a continuously developed integrated …

Assessment Of Phytoplankton Assemblages And Harmful Algal Blooms In New Jersey, Yaritza Acosta Caraballo

Theses, Dissertations and Culminating Projects

Urbanization, industrialization, and climate change have played a major role in the pollution of waterways, leading to a global increasing trend of harmful algal blooms (HAB) while jeopardizing water quality. Phytoplankton and HAB were evaluated within the highly urbanized and historically polluted state of New Jersey to help provide statewide baseline data for HAB and water quality management. A total of three studies were included in this dissertation. In the first study, phytoplankton communities were characterized in freshwaters of New Jersey during the cyanobacterial HAB season and their relationships to water quality at both statewide and ecoregion levels were examined. …

Quantifying Heterogeneity Along A Hillslope Using Seismic Refraction, Structure From Motion, And X-Ray Fluorescence In The Piedmont, South Carolina, Leah Topping

All Theses

The critical zone (CZ) is the life sustaining outer layer of the earth that spans from the top of unweathered bedrock to the tops of the trees. This dynamic zone is always evolving because a variety of chemical, physical, and biological processes transform bedrock into regolith, creating a spatially heterogeneous CZ architecture. This study aims to investigate the relationships between regolith thickness, seismic velocities, and chemical profiles as a function of slope position and it is hypothesized bedrock composition, fracture density, and foliation are the key factors controlling the physical heterogeneity in the top 1-2 meters of the CZ. To …

Net-Zero Target And Emissions From Land Conversions: A Case Study Of Maryland's Climate Solutions Now Act, Philip Hutton

All Theses

Many climate change “solution” plans include net-zero goals, which involve balancing the anthropogenic greenhouse gas emissions (GHG) with their removal. Achieving net-zero goals is particularly problematic for soils because they are often excluded from GHG inventories and reduction plans. For example, Maryland’s Climate Solutions Now Act (Senate Bill 528) put forward a target of net-zero emissions by 2045. To achieve these goals, the state of Maryland (MD) needs to quantify GHG emissions. Soils are currently excluded from MD’s GHG assessments. This study examines the challenges in meeting net-zero goals by using carbon dioxide (CO₂). The current study quantified …

The Terroir Of Swiss Cheese: A Temporal And Geomorphological Investigation Of The Martian Co2 Sublimation Pits, Racine D. Cleveland

Graduate Theses and Dissertations

Observations by NASA Mars Global Surveyor showed evidence of rough topography on the South Pole of Mars. The topography is the result of CO2 sublimation processes that occur through the changing seasons on the red planet. These sublimation areas are known to scientists as Swiss Cheese Features (SCF). SCF are erosional degradation pits that have been studied for over two decades. Studies show that these SCF increase in area over time, but these values are collected by hand on a per feature basis. Models for the pit evolution have also played a part in understanding these SCF. This work is …

The Last Drought Frontier: Building A Drought Index For The State Of Alaska, Olivia Campbell

School of Natural Resources: Dissertations, Theses, and Student Research

Drought is characterized by periods of below average precipitation. There are five major types of drought recognized in the literature: meteorological, hydrological, agricultural, socioeconomic, and ecological. A relatively new concept in the drought literature is “snow drought.” A key part of the definition of drought is that it is not always accompanied by extreme heat. This means drought can occur even in cold climates, cold seasons, and higher latitudes and altitudes, like Alaska. Drought is a natural part of climate variability, but Alaska’s climate is changing faster than any other state in the United States. Alaska is no stranger to …

Application Of A High-Resolution Climate Model Dataset To Assess Habitat Suitability For Spotted Wing Drosophila In Southwest Idaho, Elizabeth Padian

Boise State University Theses and Dissertations

As global climate change continues to produce large deviations from the normals of the 19th and 20th centuries, the agricultural sector will need to adapt to these changes in order to maintain yields and feed the global population. Crop selections, yield amounts, and pest management techniques may need to be adjusted to adapt. The Spotted Wing Drosophila (SWD) is a small fruit fly-like bug that can infest berries and stone fruit crops by burrowing into the fruit (at most points in the fruit’s lifecycle) and laying its eggs. These eggs will hatch and the larvae will burrow back out of …

Study Of Trace Elements In Southern Nevada Spring Waters And Lakes, Hyejeong Lee

UNLV Theses, Dissertations, Professional Papers, and Capstones

Comprehending the natural water resource is imperative for the entire state of Nevada and of particular significance for Southern Nevada, where rapid population growth and climate change are placing significant strain on supplies. This research underscores the significance of water chemistry in identifying potential water source areas through trace elements. For the first time, the study proposed measuring the compositions of the entire suite of metal elements, ranging from Li to U, in over 40 springs in the Moapa Valley and its upper gradient valleys, utilizing the iCAP Qc ICP-MS (Inductively Coupled Plasma Mass Spectrometer) at UNLV. The research evaluated …

College Of Natural Sciences Newsletter, March - May 2023, College Of Natural Sciences

College of Natural Sciences Newsletters and Reports

Volume 4, Issue 2

Page 1 Dean's Message
Page 2-7 Awards and Recognition
Page 8 March 3rd Corothers Seminar
Page 9 54th Geography Convention
Page 10 Spring 2023 Day of Scholars
Page 11 2023 URSCAD Snaps
Page 12-14 Media Coverage of CNS
Page 15 Open PRAIRIE Data

Glacialwater: A Dynamic Microbial Medium, Gilda Varliero, Pedro H. Lebre, Andrew G. Fountain, Beat Frey, Alexandre M. Anesio, Don A. Cowan

Geology Faculty Publications and Presentations

Microbial communities and nutrient dynamics in glaciers and ice sheets continuously change as the hydrological conditions within and on the ice change. Glaciers and ice sheets can be considered bioreactors as microbiomes transform nutrients that enter these icy systems and alter the meltwater chemistry. Global warming is increasing meltwater discharge, affecting nutrient and cell export, and altering proglacial systems. In this review, we integrate the current understanding of glacial hydrology, microbial activity, and nutrient and carbon dynamics to highlight their interdependence and variability on daily and seasonal time scales, as well as their impact on proglacial environments.

Petrographic Observations Of Stromatolites In The Late Cambrian To Early Ordovician Knox Group, Northwest Georgia And Their Relationship To Stromatolitic Fabrics Over Geologic Time, Evan Ritchey

Honors Theses

Silica deposits are common in Proterozoic carbonate platforms and are interpreted to form early in the diagenetic history of the carbonate strata. Black early diagenetic chert deposits are often associated with evidence of ancient microbial mats, or stromatolites. Proterozoic chert nodules can contain well-preserved microfossils, because silicification occurs rapidly; however, silica deposition has changed over time and it is unclear if similar deposits exist in the Cambrian period after silica-utilizing organisms evolved. The Copper Ridge Dolomite in the Knox Group, northwest Georgia, which was deposited in the late Cambrian to early Ordovician, contains black chert nodules that follow the structure …

Interactive Effects Of Fungal Community Structure And Soil Moisture On Wyoming Big Sagebrush Performance, Arden Marlene Engel

Boise State University Theses and Dissertations

Large swathes of the North American sagebrush steppe have been converted to grazing and agricultural use. Remaining fragmented areas are threatened by invasive annual grasses and associated perpetuation of increased fire frequency, with efforts to restore sagebrush after fire largely unsuccessful. Lack of success may be due, in part, to poor interactions between sagebrush seed sourced from distant locations and unfamiliar soil fungi.

A greenhouse experiment was designed to evaluate effects of soil fungal community composition on sagebrush reestablishment by answering: (1) How does inoculation with ‘coevolved’ versus ‘foreign’ fungal inoculum impact sagebrush fitness? (2) How does moisture availability modify …

An Overview Of Serial Depletions Of Global Marine Fisheries 1950 To 2019, Alison Follmer

Biological Sciences Undergraduate Honors Theses

Overfishing is a global issue that poses a significant risk to the entire ocean ecosystem in diminishing biodiversity and ecosystem function. This thesis examined the pattern and pace of fisheries depletions due to commercial fishing during the past 70 years. The Food and Agriculture Organization of the United Nations (FAO) Division of Fisheries and Aquaculture maintains a database of global hauls of marine taxa (reported in metric tonnes) from 1950 – 2019. These data were queried to determine the total number and sequence of fisheries depletions documented by the historic record. Analysis of this database showed progressive, linearly-increasing exploitation of …

Long-Term Spatial And Temporal Assessment Of Criteria Air Pollutants Concentration Trends In The Lower Rio Grande Valley Region Of Texas, Usa, Md Salahuddin Majumder

Theses and Dissertations

Air pollution is a substantial environmental challenge all over the world. This study investigated the long-term air pollution levels in the Lower Rio Grande Valley region, by utilizing data collected from five continuous ambient monitoring stations in two counties over 23 years, from January 2000 to December 2022, to analyze daily, monthly, and seasonal variations of different pollutants, including ground-level ozone, particulate matter, and carbon monoxide. This study also identified distinct daily and seasonal patterns for O3, PM2.5, PM10, and CO at each monitoring site, influenced by factors such as traffic emissions, temperature, solar radiation, indoor heating, and weather conditions. …

Identifying Taphonomic Distribution Patterns At The Gray Fossil Site, Shawn Haugrud

Electronic Theses and Dissertations

Since the early days of the discovery of the Gray Fossil Site (GFS), meticulous efforts to preserve the spatial data were a priority. Direct surveying of fossils prior to recovery, as well as grid mapping the site, provided relative spatial data within a square meter. Such efforts meant that even fragments and microfossils, recovered during the screening operations and eventual concentrate picking, maintained some spatial data. Available spatial data are used to identify smaller deposits within the greater system, as well as non-random distribution patterns among a number of GFS taxa. Patterns are particularly pronounced in the large-bodied taxa, Teleoceras …

Hydrothermal Fluid Transport Pathways Along Fractures And Veins At Brothers Volcano, Southern Kermadec Arc, Robert Atnip

Master's Theses

Hydrothermal fluid flow in fractures and veins is a key component in the mineralization of economic metals within calderas. But there are several methods by which fractures can form. Regional extension, episodic caldera collapse, and fluid overpressure all have the potential to create brittle features. Current studies focus on the formation of fractures and veins by these methods, but do not focus on the preferred movement of hydrothermal fluids through brittle features, nor which features are more dominant in active hydrothermal systems. This thesis introduces multiple studies to better understand which method of fracture creation dominates Brothers volcano. Data from …