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Hourly Precipitation Climatology Of The Southeast United States, Vincent Brown

LSU Doctoral Dissertations

Precipitation changes are one of the most important potential outcomes of a warming climate because of how essential it is to society and ecosystems. Sub-daily precipitation time series provide more information on precipitation characteristics, particularly frequency, intensity, and duration compared to daily data. In a series of four peer-reviewed manuscripts, this research investigates sub-daily precipitation characteristics from a climatological perspective. The first study introduces a climatology of hourly precipitation for four first-order weather stations across Louisiana, explores possible changes in the hourly precipitation distribution, and links winter Gulf of Mexico sea surface temperatures to the frequency of hours with precipitation. …

Eocene Terrestrial Mammals From Central Georgia, Parker D. Rhinehart, Alfred J. Mead, Dennis Parmley

Georgia Journal of Science

Descriptions of fossils of Eocene terrestrial mammals from the southeastern United States are rare, and particularly so in the Eocene sediments of Georgia. Here we describe a small collection of fossilized teeth and tooth fragments representing four mammalian taxa. The fossils were recovered by surface collecting overburden sediments and screen washing in situ Clinchfield Formation sediments exposed in an inactive kaolin mine, Hardie Mine, in Wilkinson County, Georgia. The Clinchfield Formation has been described as a Late Eocene coastal unit with abundant gastropods, bivalves, sharks, and rays. This is the first detailed description of terrestrial mammals from this unit. Although …

Climate Change Impacts On Winter Wheat Yield In Northern China, Xiu Geng, Fang Wang, Wei Ren, Zhixin Hao

Plant and Soil Sciences Faculty Publications

Exploring the impacts of climate change on agriculture is one of important topics with respect to climate change. We quantitatively examined the impacts of climate change on winter wheat yield in Northern China using the Cobb–Douglas production function. Utilizing time-series data of agricultural production and meteorological observations from 1981 to 2016, the impacts of climatic factors on wheat production were assessed. It was found that the contribution of climatic factors to winter wheat yield per unit area (WYPA) was 0.762–1.921% in absolute terms. Growing season average temperature (GSAT) had a negative impact on WYPA for the period of 1981–2016. A …

Cogongrass (Imperata Cylindrica (L.) Beauv.) In Louisiana: Cause And Consequence, Lorissa A. Radunzel-Davis

LSU Master's Theses

Cogongrass (Imperata cylindrica (L.) Beauv.), an invasive species from East Asia, is found worldwide and is problematic in several countries. In the United States, it grows primarily in the Southeast, reducing biodiversity by growing in dense patches and potentially causing mortality and reducing value of native and planted pinelands due to a high burning temperature. Using Lee Memorial Forest, a Louisiana State University AgCenter property in Washington Parish as a study site, this thesis explores cogongrass in Louisiana with emphasis on soil microbes and soil legacy effects on native plant species. Cogongrass populations at Lee Memorial Forest were more …

Unexplored Diversity Of The Mesophotic Echinoderm Fauna Of The Easter Island Ecoregion, Ariadna Mecho, Erin E. Easton, Javier Sellanes, Matthias Gorny, Christopher Mah

School of Earth, Environmental, & Marine Sciences Faculty Publications

The Easter Island ecoregion (EIE) is one of the most remote marine areas of the world and encompasses a vast and fragile ecosystem including oceanic islands and seamounts. In January 2014 and March 2016, a remotely operated vehicle was used to explore a subsurface peak off Easter Island (27.23°S, 109.48°W) and a seamount (26.92°S, 110.26°W), respectively located 10 km southwest and 98 km west of the island. More than 950 echinoderms were observed in the 5 h of video recorded during the seven dives conducted at depths between ~ 160 and 280 m. The communities of echinoderms observed at these …

Hydrologic Trends And Spatial Relationships Of Stream Temperature And Discharge In Urbanizing Watersheds In The Portland Metropolitan Area Of The Pacific Northwest, Emma Lee Brenneman

Dissertations and Theses

This study explores various relationships of streamflow and stream temperature over the Portland Metropolitan area in two urbanizing watersheds. Four stream temperature and discharge metrics were derived from USGS stream gauges in the Tualatin River and Johnson Creek watersheds and were analyzed for monotonic trends. Additionally, this study explored the sensitivity of stream temperature to air temperature and streamflow to assess where locations throughout the watershed may be more sensitive to these changes. Relationships among stream temperature, air temperature, and streamflow were assessed using linear and nonlinear bivariate regression for yearly values and summer months. Additionally, this study seeks to …

Usu Sponsors Recent Ucowr Conference At Snowbird, Ut, Utah Water Research Laboratory

News

USU recently sponsored the UCOWR/NIWR Annual Water Resources Conference at Snowbird, Utah, June 11-13, 2019. UWRL faculty member and UCOWR lead delegate David Stevens served as Conference Chair, and the conference planning committee consisted of delegates David Stevens, Chair (UWRL); Jeffery Horsburgh (UWRL), Bethany Neilson (UWRL); and David Rosenberg (UWRL); and Mac McKee (Retired). Additional USU delegates include Belize Lane (UWRL), Joanna Endter-Wada (Biology/NR), Laurie McNeill (UWRL), and Joe Wheaton (Watershed Sci). USU students and faculty also participated with presentations and posters over the course of the four-day conference.

Scenes From The Swale: Investigating Spatial And Temporal Dimensions Of Nitrogen Cycling In Urban Stormwater Bioretention Facilities, Erin Nicole Looper

Dissertations and Theses

Urban development is transforming landscapes at unprecedented rates. Human activities and landscape modifications associated with urbanization extensively increase hydrologic demands and modify natural hydrologic systems; consequently, population growth occurring in urban areas increases pressure on water resources. Urban aquatic ecosystems are vulnerable to impacts associated with increased connectivity with urban surfaces and hydrologic changes that initiate long-term changes in receiving waterbodies. Nitrogen (N) loading from urban and suburban catchments to receiving surface waters can lead to impairment of aquatic ecosystems and is a concern in many cities with water quality issues. To improve urban water quality, cities are increasingly adopting …

Rare Earth Geochemistry Of Apatitic Fossils From The Middle-Upper Ordovician Southern Margin Of Laurentia, Rafael Adrian Villanueva

LSU Master's Theses

Widespread deposition of phosphate and a transition from tropical to cool water carbonates is seen throughout Middle-Upper Ordovician Nashville Dome area spanning the M4/M5 sequence boundary. Hypotheses explaining the onset of these lithologic changes have included the onset of glaciation, drawdown of CO₂ related to the Guttenburg Isotope Carbon Excursion (GICE), and siliciclastic weathering, yet none of these studies have provided definitive evidence that shows any of these are the sole factor driving paleoenvironmental changes across the M4/M5 boundary. In order to test whether rapid subsidence along the southeastern margin of Laurentia may have caused an influx of phosphate …

Development Of An Rfid Tracking System For Coarse Sediment Transport In A Flume Setting, Peter Mahoney Jr.

ENGS 88 Honors Thesis (AB Students)

Development of an RFID Tracking System for Coarse Sediment Transport in a Flume Setting

Peter E. Mahoney

Professor Carl Renshaw

Understanding how sediment moves through a fluvial system has important implications for the study of river systems, sediment flux, and flood events. Over the past decade, RFID (radio frequency identification) technology has emerged as a useful method for tracking the movement and transport of coarse sediment clasts. This approach has been used to measure the transport of large clasts in mid-sized streams, ephemeral channels, and laboratory flume settings. However, this research utilized finite transport of sediment and focused on accurately …

Chronostratigraphic Correlation Of The Burnt Bluff Group Across The Michigan Basin, Usa, Mohammed A. Al-Musawi

Masters Theses

In the Michigan Basin, the Burnt Bluff Group (BBG) is lower Middle Silurian in age (Llandovery), and is composed of limestones and dolostones. The BBG is bounded above by the Schoolcraft Formation and below by the Cabot Head Shale. The BBG in northern Lower Michigan is composed of three formations, including the Lime Island, Byron, and Hendricks, which reflect deposition on a broad shallow marine shelf. In contrast, the BBG in central Michigan is composed of a single lithologic unit called informally the “undifferentiated BBG (UD-BBG),” which reflects deposition in a deeper marine basin. Lithostratigraphically, the three formations in the …

An Analysis Of Differential Reflectivity Arc Characteristics In 109 Supercell Storms, Matthew Wilson

Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research

Differential reflectivity (Z_DR)arcs are one of the most prominent dual-polarization features of supercell storms, and are manifest as an arc-shaped area of high Z_DR along a supercell’s forward flank reflectivity gradient. Since previous modelling studies have hypothesized that the magnitude of the drop-size sorting by the storm-relative wind which creates the arc signature is related to the strength of the low-level shear and SRH in a storm’s environment, the presence of a strong Z_DR arc is often said to indicate that a storm may have the potential to develop strong low-level rotation and potentially become tornadic. …

Characterization Of Cross-Bed Depositional Processes In The Coconino Sandstone, Sarah A. Maithel

Loma Linda University Electronic Theses, Dissertations & Projects

The Permian Coconino Sandstone of northern and central Arizona is widely recognized as a classic eolian dune deposit, with conspicuous large-scale cross-beds that are interpreted as preserved dune foresets. On modern bedforms, fine-scale processes – which include grainflow, grainfall, and ripple migration – transport and deposit sediment, and these may provide useful analogs for interpreting ancient deposits. Even though the Coconino Sandstone is well known, such fine-scale process models have not been adequately developed to explain its cross-bed deposition. Furthermore, observed discrepancies between the sandstone and some eolian criteria suggest that additional study is needed to explore and refine these …

Behavioral Causes Of Paleopathologies In Cretaceous Edmontosaurus Annectens, Lance Formation, Wyoming, Bethania C. T. Siviero

Loma Linda University Electronic Theses, Dissertations & Projects

The study of dinosaur paleopathology has enriched our understanding of their living conditions and their intra- and interspecific behavior. In this study, I examined lesions on bones from a monospecific bone bed (Edmontosaurus annectens) and their implications for E. annectens behavior and the ecological conditions that affected this population. The bone bed contains abundant, mostly well-preserved, scattered, and disarticulated bones, mostly representing an adult population of E. annectens. From the 3013 bones examined, 96 bones displayed genuine pathologies such as: hypertrophic ossification, healed fractures, tooth traces, idiopathic or traumatic shaft angulation, bone fusion, degenerative joint diseases, osteochondrosis, infection, neoplasm, and …

Mercury Cycling In The North Pacific Subtropical Gyre As Revealed By Mercury Stable Isotope Ratios, Laura C. Motta, Joel D. Blum, Marcus W. Johnson, Blaire P. Umhau, Brian N. Popp, Spencer J. Washburn, Jeffrey C. Drazen, Claudia R. Benitez-Nelson, Cecelia C. S. Hannides, Hilary G. Close, Carl H. Lamborg

Faculty Publications

The oceans are an important global reservoir for mercury (Hg), and marine fish consumption is the dominant human exposure pathway for its toxic methylated form. A more thorough understanding of the global biogeochemical cycle of Hg requires additional information on the mechanisms that control Hg cycling in pelagic marine waters. In this study, Hg isotope ratios and total Hg concentrations are used to explore Hg biogeochemistry in oligotrophic marine environments north of Hawaii. We present the first measurements of the vertical water column distribution of Hg concentrations and the Hg isotopic composition in precipitation, marine particles, and zooplankton near Station …

Genetic Sequencing For Measuring Biodiversity In Recent And Ancient Marine Sediments, Lauren Judge

Celebration of Learning

Taxonomic biodiversity, measured by counting the number of species present in a given area, is the most common method of capturing ecosystem biodiversity in recent and ancient environments. While this method is widely accepted, it is limited by poor preservation and identification of many individuals, making it impossible to include every species within an ecosystem and resulting in the loss of some diversity information. To address this issue, we measured the genetic biodiversity (in which species are determined based on sequencing of their DNA) of shallow marine ecosystems by extracting and sequencing the 18S ribosomal gene from bulk carbonate sediment …

Managing Agroecosystems For Soil Microbial Carbon Use Efficiency: Ecological Unknowns, Potential Outcomes, And A Path Forward, Cynthia M. Kallenbach, Matthew D. Wallenstein, Meagan E. Schipanksi, A. Stuart Grandy

Faculty Publications

Agricultural systems are increasingly managed for improving soil carbon (C) accumulation. However, there are limits to C returns in agricultural systems that constrain soil C accumulation capacity. Increasing the efficiency of how soil microbes process C is gaining interest as an important management strategy for increasing soil C and is a key feature of soil C dynamics in many new microbial-explicit models. A higher microbial C use efficiency (CUE) may increase C storage while reducing C system losses and is a fundamental trait affecting community assembly dynamics and nutrient cycling. However, the numerous ecological unknowns influencing CUE limit our ability …

Seamless Lidar Surveys Reveal Rates And Patterns Of Subsidence In The Mississippi River Delta, Celeste E. Woock

LSU New Orleans Theses and Dissertations

Light Detection and Ranging (Lidar) data are used to report the temporal and spatial patterns of subsidence as well as the potential contributors to subsidence within the Barataria and Terrebonne Bays. In recent decades, subsidence in southeast Louisiana has become a topic of substantial and growing concern to the scientific community, the local residents, and all those invested in the region. Lidar data were acquired from the United States Geological Survey (USGS) and the LSU Center for Geoinformatics. The data has been manipulated to map the differenced Lidar, complete an instantaneous slope analysis, and determine the thickness of the Holocene …

Toward The Ultrasonic Sensing Of Organic Carbon In Seagrass-Bearing Sediments, Gabriel R. Venegas, Abdullah Rahman, Kevin M. Lee, Megan S. Ballard, Preston S. Wilson

School of Earth, Environmental, & Marine Sciences Faculty Publications

Ten percent of all organic carbon (Corg) absorbed by the ocean each year is stored in seagrass-bearing sediments. The preservation of these carbon stores is considered a vital method to mitigate climate change. Seagrass-bearing sediments have been correlated with sediment geophysical properties yet have not been related to sediment acoustic properties. For this purpose, sediment cores were collected from a Thalassia testudinum seagrass meadow in South Texas, USA, where geophysical, acoustical, and Corg properties were measured. It is hypothesized that when deposits of Corg adsorb onto mineral surfaces and are stored in pore spaces, compliant layers between grain contacts and …

The Effect Of Depositional Environment And Early Marine Diagenesis On Carbonate-Associated Sulfate, Jocelyn Ann Richardson

Arts & Sciences Graduate Student Theses and Dissertations

The long-term redox state of Earth’s surface environments is governed by the relative burial proportions of redox-sensitive carbon and sulfur species throughout geologic time. The sulfur isotopic signature of seawater sulfate (δ34SSO4) traces the relative proportions of sulfur buried as sulfide (commonly pyrite) and sulfate (as evaporites, barite or carbonate-associated sulfate) and weathering source to the ocean. Thus, δ34SSO4 is a powerful tool to understand the evolution of redox conditions and the marine biogeochemical sulfur cycle. Due to the spatial and temporal extent of carbonates in the rock record, carbonate-associated sulfate (δ34SCAS) is a common proxy for the isotopic composition …

Cave Temperature And Management Implications In Lehman Caves, Great Basin National Park, Usa, Stanka Šebela, Gretchen Baker, Barbara Luke

Civil and Environmental Engineering and Construction Faculty Research

Cave air temperature was measured at six locations in Lehman Caves (USA) for one year at hourly intervals. Lehman is a show cave in a national park, treasured for its geological and biological resources. The two monitoring locations that are off of the tour route and, also, relatively distant from the cave’s entrances displayed nearly constant air temperature during the year. The other four sites, along the tour route, show daily temperature variation as well as annual fluctuation. After visitation levels decreased in the autumn, cave temperatures lagged but eventually reached an equilibrium which demonstrates recovery in the quiet winter. …

Understanding The Meaning Of Microbialites As Geobiological Archives, Scott Randall Beeler

Arts & Sciences Graduate Student Theses and Dissertations

Microbialites, sedimentary structures formed from the interaction of microorganisms with their environment, provide one of the oldest and most complete records of life on Earth, making them an invaluable tool in the field of geobiology. However, much of the information that could be gained from microbialites remains obscured due to our incomplete understanding of how variability in the microbial, geochemical, and physical processes driving their formation affect their morphological and geochemical characteristics. Modern environments of active microbialite formation provide the opportunity to study the relationship between variability in these environmental processes and the resultant mineral product and can act as …

Detecting Ocean Microplastics With Remote Sensing In The Near-Infrared: A Feasibility Study, Jandlyn Bentley

Honors Program Theses and Projects

Since plastic began entering the oceans in the 1950s, trends have shown that this pollution has been and will continue to increase in the future. The only method to estimate the abundance and distribution of ocean plastic pollution is by computer-generated models using data from in-situ plankton net tows, which are costly, time consuming, and cover a relatively small scale. This project investigates the potential of detecting ocean microplastics with satellite remote sensing based on theoretically elevated near-infrared (NIR) reflectance. Emphasis was placed on the Great Pacific Garbage Patch in the North Pacific Ocean, notorious for its extremely high concentration …

Floodwater Impact On Galveston Bay Phytoplankton Taxonomy, Pigment Composition And Photo-Physiological State Following Hurricane Harvey From Field And Ocean Color (Sentinel-3a Olci) Observations, Eurico D'Sa

Faculty Publications

Phytoplankton taxonomy, pigment composition and photo-physiological state were studied in Galveston Bay (GB), Texas (USA), following the extreme flooding associated with Hurricane Harvey (25-29 August 2017) using field and satellite ocean color observations. The percentage of chlorophyll a (Chl a) in different phytoplankton groups was determined from a semi-analytical IOP (inherent optical property) inversion algorithm. The IOP inversion algorithm revealed the dominance of freshwater species (diatom, cyanobacteria and green algae) in the bay following the hurricane passage (29 September 2017) under low salinity conditions associated with the discharge of floodwaters into GB. Two months after the hurricane (29-30 October 2017), …

Fluid Transport In Porous Media For Engineering Applications, Eric M. Benner

Chemical and Biological Engineering ETDs

This doctoral dissertation presents three topics in modeling fluid transport through porous media used in engineering applications. The results provide insights into the design of fuel cell components, catalyst and drug delivery particles, and aluminum- based materials. Analytical and computational methods are utilized for the modeling of the systems of interest. Theoretical analysis of capillary-driven transport in porous media show that both geometric and evaporation effects significantly change the time dependent behavior of liquid imbibition and give a steady state flux into the medium. The evaporation–capillary number is significant in determining the time-dependent behavior of capillary flows in porous media. …

Root Hair Single Cell Type Specific Profiles Of Gene Expression And Alternative Polyadenylation Under Cadmium Stress, Jingyi Cao, Congting Ye, Guijie Hao, Carole Dabney-Smith, Arthur G. Hunt, Qingshun Q. Li

Plant and Soil Sciences Faculty Publications

Transcriptional networks are tightly controlled in plant development and stress responses. Alternative polyadenylation (APA) has been found to regulate gene expression under abiotic stress by increasing the heterogeneity at mRNA 3′-ends. Heavy metals like cadmium pollute water and soil due to mining and industry applications. Understanding how plants cope with heavy metal stress remains an interesting question. The Arabidopsis root hair was chosen as a single cell model to investigate the functional role of APA in cadmium stress response. Primary root growth inhibition and defective root hair morphotypes were observed. Poly(A) tag (PAT) libraries from single cell types, i.e., root …

Chloride Signature And Transport In An Urban-Agricultural Watershed, Andrew Oberhelman

Theses and Dissertations

Manual and high frequency observations (n = 535) of chloride (Cl-), bromide (Br-), nitrate (NO3-N), sodium (Na+), calcium (Ca2+), and potassium (K+) of stream and tile-drain waters were conducted in an urban-agricultural watershed (8% urban, 87% agriculture) to investigate the importance of stormflow to Cl- transport and to explore potential differences in the signature of Cl- originating from an urban source as compared to an agricultural source. The study was conducted in Evergreen Lake Watershed (ELW) located in central Illinois. Manual samplings were conducted on a weekly interval from February 2018 to February 2019 at three station along Six Mile …

Grain Size And Vegetation As Controlling Variables Of Stream Channel Morphology, Grant Colip

Senior Honors Projects, 2010-2019

Streams are one of the major driving forces that shape the landscapes in the Shenandoah Valley of Virginia and the eastern United States as a whole, and they serve an important role in transporting both water and sediment to the Atlantic Ocean. However, streams are often modified for human use, thus altering their natural equilibrium. These alterations have frequently led to the degradation of channel stability as well as damage to property and infrastructure. A better understanding of how both grain size (D₅₀) and vegetation impact stream sinuosity (S) is needed to analyze the prevalence of channel degradation …

The Potential Acidification Of The Mulberry River, Arkansas, Jason Richard Burgess-Conforti

Graduate Theses and Dissertations

The Mulberry River is a 110 km long tributary of the Arkansas River in northwest Arkansas and has been designated as a National Wild and Scenic River since 1992. In 2008, the Mulberry River was added to the 303(d) list of impaired water bodies due to the low pH of a 14.6 km segment of the river which has since increased to 68.7 km. To date, there has been little research performed on the Mulberry River and long-term routinely sampled water quality data is unavailable. The objectives of this dissertation were 1) to evaluate changes in water quality of the …

Analysis Of Permaculture’S Water Conservation And Crop Supporting Abilities, Hannah Chaney

Mahurin Honors College Capstone Experience/Thesis Projects

In the Middle East, virtually all agriculturally viable land is under high threat of desertification due to poor land and resource management and climate change. Mulching using straw flakes (straw mulch permaculture) is a method commonly used in successful dry land permaculture projects in the Middle East. We proposed that straw mulch permaculture would increase the amount of soil moisture during dry periods and that this method would not impact the growth and survival of the crop. In order to test this hypothesis, we took soil samples from plots with and without straw mulch permaculture in Bowling Green, KY and …