Digital Commons Network^™

Hypothetical Bias Mitigation In Representative And Convenience Samples, Jerrod M. Penn, Daniel R. Petrolia, J. Matthew Fannin

Faculty Publications

This is a case study comparing outcomes for a probability-based representative sample versus a non-probability convenience sample for the valuation of beach condition information among Gulf of Mexico residents. We test the efficacy of several techniques used to adjust for hypothetical bias and sample weighting to reduce hypothetical willingness to pay (WTP). Weighting makes the WTP between the two samples similar, but model equivalence with respect to the significance of explanatory variables is rejected. The results support the use of certainty follow-ups, which consistently reduced WTP, regardless of the sampling approach or weighting.

Subaqueous Topographic Deformation In Abandoned Delta Lobes—A Case Study In The Yellow River Delta, China, Yunfeng Zhang, Yingying Chai, Caiping Hu, Yijun Xu, Yuyan Zhou, Huanliang Chen, Zijun Li, Shenting Gang, Shuwei Zheng

Faculty Publications

Reduction in river discharge and sediment load has left deltaic lobes in the world’s many river deltas starving, but knowledge of how the subaqueous topography of these abandoned subdeltas responds to environmental changes is limited. In this study, we aimed to determine the long-term dynamics of the subaqueous seabed of abandoned delta lobes to advance current knowledge. As a case study, we selected an abandoned subdelta on the Yellow River Delta of the Bohai Sea, China, for which three-decade long (1984–2017) bathymetric data and long-term river discharge and sediment load records are available. We analyzed the seafloor surface change and …

Indirect Functional Effects Of Neighbors On Food Web Compartments Could Not Overcome Density-Dependent Limited Growth Of A Grazing Minnow, Garrett W. Hopper, Keith B. Gido, Caryn C. Vaughn

Faculty Publications

Ecosystems include diverse taxonomic and functional groups of animals with variable levels of niche overlap that can lead to direct and indirect interactions with positive or negative outcomes. Species feeding at low trophic positions might be sensitive to interactions with co-occurring functional groups (neighbors) that influence their food resources through various processes, such as indirect nutrient subsidies and trophic cascades. Employing a target-neighbor experimental design using large, outdoor mesocosms, we tested whether adding neighbors with different functional traits affected food web compartments relative to a control group that had grazing minnows, Campostoma anomalum (Central Stoneroller). Additionally, we tested whether growth …

A Delayed Intervention Start Randomized Controlled Trial Of High- And Low-Tech Communication Training Approaches For School-Age Autistic Children With Co-Occurring Intellectual Disability, Shawn P. Gilroy, Joseph P. Mccleery, Geraldine Leader

Faculty Publications

The researchers designed a delayed intervention start randomized controlled trial to compare improvements in functional communication following augmentative and alternative communication (AAC) interventions. The study compared outcomes from function-based applied behavior analytic (ABA) and eclectic non-ABA forms of classroom-based communication strategies (waitlist control) as well as from high- and low-tech forms of AAC. High-tech AAC consisted of tablet-based communication, and low-tech AAC used an exchange of picture cards. The community-based sample consisted of 29 autistic children with a co-occurring intellectual disability. Participants were randomized to groups (AAC, waitlist control), and each group received approximately 3 months of communication intervention. Multilevel …

A Simple Trail Camera Modification Reveals Red-Bellied Woodpeckers As Important Egg Predators Of Box-Nesting Wood Ducks, Dylan L. Bakner, Kevin M. Ringelman

Faculty Publications

Artificial nesting structures have been used to aid the recovery and maintenance of certain avian populations such as the wood duck (Aix sponsa). The success of nest boxes for wood ducks relies on excluding common nest predators such as raccoons (Procyon lotor) and rat snakes (Pantherophis spp.) via the use of predator guards; however, woodpeckers cannot be excluded. Red-bellied woodpeckers (Melanerpes carolinus) are foraging generalists and have been anecdotally observed preying on wood duck eggs where documenting predation events is difficult to accomplish through traditional nest box monitoring. Here, we used custom-modified trail cameras to document egg depredations and foraging …

Immune Genotypes, Immune Responses, And Survival In A Wild Bird Population, Martha J. Nelson-Flower, Leanne A. Grieves, Jane M. Reid, Ryan R. Germain, Savo Lazic, Sabrina S. Taylor, Elizabeth A. Macdougall-Shackleton, Peter Arcese

Faculty Publications

Individuals vary in their immune genotype, inbreeding coefficient f, immune responses, survival to adulthood, and adult longevity. However, whether immune genes predict survival or longevity, whether such relationships are mediated through immune responses, and how f affects immune genotype remain unclear. We use a wild song sparrow (Melospiza melodia) population in which survival to adulthood, adult longevity, and f were measured precisely, and in which immune responses have previously been assessed. We investigate four toll-like receptor (TLR) and the major histocompatibility complex (MHC) class IIB exon 2 genes. We test whether immune genes predict fitness (survival to adulthood or adult …

Students' Consumption Of High And Low Nutrition Foods And Reduced Plate Waste By Schools' Wellness-Related Policies And Garden Program Participation, Andrea S. Richardson, Alvin Nugroho, Tamara Dubowitz, Dana Schultz, Corby K. Martin

Clinical Research Faculty Publications

Background: Participation in school-based programs that may support children's nutritious dietary behaviours varies across schools. We examined school participation in wellness-related policies, school-based garden programs and students' dietary behaviours. Methods: Among matching schools who did and did not participate in school-based garden programs, we analysed the lunches of 80 Pittsburgh Public Schools (PPS) students in 1st, 2nd, 6th and 7th grades during Autumn 2019 using digital food photography. We also acquired school wellness policy data. Using cross-sectional linear regression, we estimated the association between school-based garden programming, wellness-related policies and dietary outcomes, adjusting for grade. Results: School's implementation of nutrition …

A Comparison Of Bat Calls Recorded By Two Acoustic Monitors, Jane M. Kunberger, Ashley M. Long

Faculty Publications

Recent advances in low-cost autonomous recording unit (ARU) technology have made large-scale bat monitoring projects more practical, but several key features of ARUs (e.g., microphone quality and triggering thresholds) can influence their ability to detect and record bats. As such, it is important to quantify and report variation in ARU performance as new recording systems become available. We used the automated classification software SonoBat to compare the numbers of call files, echolocation pulses, and species recorded by a commonly used, full-spectrum bat detector-the Song Meter SM4BAT-FS-and a less expensive, open-source ARU that can detect ultrasound-the AudioMoth. We deployed paired ARUs …

Demystifying Longitudinal Data Analyses Using Structural Equation Models In School Psychology, Garret J. Hall, Kelly N. Clark

Faculty Publications

Structural equation models (SEM) are a method of latent variable analysis that offer a high degree of flexibility in terms of modeling methods for applied research questions. Recent advancements associated with longitudinal SEM have unlocked innovative ways to decompose variance and to estimate mean trends over time (e.g., Allison et al., 2017; Berry & Willoughby, 2017; Hamaker et al., 2015; McArdle & Nesselroade, 2014). However, these longitudinal methods are not necessarily readily accessible to scholars seeking to advance theory and practice in school psychology. Importantly, not all longitudinal data are the same and not all longitudinal SEMs are the same; …

Associations Between Neuropsychiatric Symptoms Of Affective And Vegetative Domains And Brain Morphology In Aging People With Mild Cognitive Impairment And Alzheimer's Disease, Adriana Cannizzaro, Lucas Ronat, Lyna Mariam El Haffaf, Alexandru Hanganu, Michael Weiner, Paul Aisen, Paul Aisen, Paul Aisen, Ronald Petersen, Clifford R. Jack, William Jagust, William Jagust, John Q. Trojanowki, John Q. Trojanowki, Arthur W. Toga, Arthur W. Toga, Laurel Beckett, Laurel Beckett, Robert C. Green, Robert C. Green, Andrew J. Saykin, Andrew J. Saykin, John Morris, Enchi Liu, Tom Montine, Ronald Petersen, Ronald Petersen, Anthony Gamst, Anthony Gamst, Ronald G. Thomas, Michael Donohue, Michael Donohue, Sarah Walter, Devon Gessert

Clinical Research Faculty Publications

Objective: Neuropsychiatric symptoms (NPS) are common in mild cognitive impairment (MCI) and even more in Alzheimer's disease (AD). The symptom-based cluster including nighttime disturbances, depression, appetite changes, anxiety, and apathy (affective and vegetative symptoms) was associated with an increased risk of dementia in MCI and has common neuroanatomical associations. Our objective was to investigate the differences in brain morphology associations with affective and vegetative symptoms between three groups: cognitively normal older adults (CN), MCI and AD. Material and Methods: Alzheimer's Disease Neuroimaging Initiative data of 223 CN, 367 MCI and 175 AD, including cortical volumes, surface areas and thicknesses and …

Regional Neuroanatomic Effects On Brain Age Inferred Using Magnetic Resonance Imaging And Ridge Regression, Roy J. Massett, Alexander S. Maher, Phoebe E. Imms, Anar Amgalan, Nikhil N. Chaudhari, Nahian F. Chowdhury, Andrei Irimia, Michael W. Weiner, Paul Aisen, Ronald Petersen, Clifford R. Jack, William Jagust, John Q. Trojanowki, Arthur W. Toga, Laurel Beckett, Robert C. Green, Andrew J. Saykin, John C. Morris, Richard J. Perrin, Leslie M. Shaw, Zaven Khachaturian, Maria Carrillo, William Potter, Lisa Barnes, Marie Bernard, Hector González, Carole Ho, John K. Hsiao, Jonathan Jackson, Eliezer Masliah, Donna Masterman, Ozioma Okonkwo, Laurie Ryan, Nina Silverberg

Clinical Research Faculty Publications

The biological age of the brain differs from its chronological age (CA) and can be used as biomarker of neural/cognitive disease processes and as predictor of mortality. Brain age (BA) is often estimated from magnetic resonance images (MRIs) using machine learning (ML) that rarely indicates how regional brain features contribute to BA. Leveraging an aggregate training sample of 3 418 healthy controls (HCs), we describe a ridge regression model that quantifies each region’s contribution to BA. After model testing on an independent sample of 651 HCs, we compute the coefficient of partial determination R̄2p for each regional brain volume to …

Quantum Fluctuations Spatial Mode Profiler, Charris Gabaldon, Pratik Barge, Savannah L. Cuozzo, Irina Novikova, Hwang Lee, Lior Cohen, Eugeniy E. Mikhailov

Faculty Publications

The spatial mode is an essential component of an electromagnetic field description, yet it is challenging to characterize it for optical fields with the low average photon number, such as in a squeezed vacuum. We present a method for the reconstruction of the spatial modes of such fields based on the homodyne measurements of their quadrature noise variance performed with a set of structured masks. We show theoretically that under certain conditions, we can recover individual spatial mode distributions by using the weighted sum of the basis masks, where weights are determined using measured variance values and phases. We apply …

8(Meso)-Pyridyl-Bodipys: Effects Of 2,6-Substitution With Electron-Withdrawing Nitro, Chloro, And Methoxycarbonyl Groups, Caroline Ndung’U, Petia Bobadova-Parvanova, Daniel J. Lamaster, Dylan Goliber, Frank R. Fronczek, Maria Da Graça H. Vicente

Faculty Publications

The introduction of electron-withdrawing groups on 8(meso)-pyridyl-BODIPYs tends to increase the fluorescence quantum yields of this type of compound due to the decrease in electronic charge density on the BODIPY core. A new series of 8(meso)-pyridyl-BODIPYs bearing a 2-, 3-, or 4-pyridyl group was synthesized and functionalized with nitro and chlorine groups at the 2,6-positions. The 2,6-methoxycarbonyl-8-pyridyl-BODIPYs analogs were also synthesized by condensation of 2,4-dimethyl-3-methoxycarbonyl-pyrrole with 2-, 3-, or 4-formylpyridine followed by oxidation and boron complexation. The structures and spectroscopic properties of the new series of 8(meso)-pyridyl-BODIPYs were investigated both experimentally and computationally. The BODIPYs bearing 2,6-methoxycarbonyl groups showed enhanced …

The Distribution Of Surface Soil Moisture Over Space And Time In Eastern Taylor Valley, Antarctica, Mark R. Salvatore, John E. Barrett, Laura E. Fackrell, Eric R. Sokol, Joseph S. Levy, Lily C. Kuentz, Michael N. Gooseff, Byron J. Adams, Sarah N. Power, J. Paul Knightly, Haley M. Matul, Brian Szutu, Peter T. Doran

Faculty Publications

Available soil moisture is thought to be the limiting factor for most ecosystem processes in the cold polar desert of the McMurdo Dry Valleys (MDVs) of Antarctica. Previous studies have shown that microfauna throughout the MDVs are capable of biological activity when sufficient soil moisture is available (~2–10% gravimetric water content), but few studies have attempted to quantify the distribution, abundance, and frequency of soil moisture on scales beyond that of traditional field work or local field investigations. In this study, we present our work to quantify the soil moisture content of soils throughout the Fryxell basin using multispectral satellite …

Constraints On The Timing Of The India-Asia Collision And Unroofing History Of The Himalayan Orogen Using Detrital Zircon U-Pb-Hf And Whole-Rock Sr-Nd Isotopes In Cretaceous-Miocene Lesser Himalayan Sedimentary Rocks, Wei Feng, Qingquan Meng, Chunhui Song, Xiaomin Fang, Guangsheng Zhuang, Pengju He, Shufen Yang, Jing Zhang, Yongfa Chen, Yihu Zhang

Faculty Publications

Cretaceous-Miocene sedimentary rocks in the Nepalese Lesser Himalaya provide an opportunity to decipher the timing of India-Asia collision and unroofing history of the Himalayan orogen, which are significant for understanding the growth processes of the Himalayan-Tibetan orogen. Our new data indicate that detrital zircon ages and whole-rock Sr-Nd isotopes in Cretaceous-Miocene Lesser Himalayan sedimentary rocks underwent two significant changes. First, from the Upper Cretaceous-Palaeocene Amile Formation to the Eocene Bhainskati Formation, the proportion of late Proterozoic-early Palaeozoic zircons (quantified by an index of 500–1200 Ma/1600–2800 Ma) increased from nearly 0 to 0.7–1.4, and the percentage of Mesozoic zircons decreased from …

Thermoset Polymer Composites With Gradient Natural And Synthetic Fiber Reinforcement: Self-Healing, Shape-Memory, And Fiber Recyclability, Sakil Mahmud, John Konlan, Jenny Deicaza, Rachel Anna Schmidt, Guoqiang Li

Faculty Publications

Natural fibers have high potential as renewable reinforcement for polymers; however, their lower load-carrying capacity compared to synthetic fibers significantly limits the wide application in fiber-reinforced polymer composites. In laminated composite beams under bending load, the normal stress is the highest on the top and bottom layers but is zero at the mid-plane, with almost a linear normal strain distribution. Although the shear stress is the highest at the mid-plane, it may not be a major concern as most polymers can survive the high shear stress. Using this concept, we have designed a hybrid fiber reinforcement in a gradient manner: …

Voting In The Mall - Understanding Political Consumerism In The United States And Europe, Kwadwo Poku-Agyemang

LSU Doctoral Dissertations

This dissertation explores the various traits that predispose individuals or groups to participate in political boycotts by refraining from purchasing goods and services from companies with the goal of promoting their political beliefs and goals. Specifically, this research considers the effects of political ideology, attitudes toward historically-marginalized groups, and identification with grievance groups shape self-reported participation in political consumerism in the United States and Europe. Using data from the 2016 and 2020 American National Election Survey and the eighth, nineth and tenth rounds of the European Social Survey, I find that although political consumerism has been seen as a liberal …

Contrasting Responses Of Atlantic And Pacific Tropical Cyclone Activity To Atlantic Multidecadal Variability, Huanping Huang, William D. Collins, Christina M. Patricola, Yohan Ruprich-Robert, Paul A. Ullrich, Alexander J. Baker

Faculty Publications

This research assesses the influences of Atlantic Multidecadal Variability (AMV) on global tropical cyclones (TCs) using two large ensembles of idealized global climate model simulations with opposite signs of AMV forcings superimposed (i.e., AMV+ and AMV–). We first detect TCs and then compare TC activity by basin in the two AMV experiments. We find contrasting responses of Atlantic and Pacific TC frequency to the AMV anomalies. Compared to AMV–, AMV+ significantly increases TC frequency in the North Atlantic, including those making landfalls. The increase is explained by warmer sea surface temperature, higher relative humidity, increased relative vorticity, and weaker vertical …

Synthesis Of An Acinetobacter Baumannii Lipooligosaccharide Subunit, James M. Armstrong Ii

LSU Doctoral Dissertations

Acinetobacter baumannii is a Gram-negative, multi drug-resistant bacterium that was placed on the World Health Organization’s watchlist of drug-resistant bacteria. A. baumannii is an ESKAPE pathogen, one of six increasingly antimicrobial-resistant bacteria that are responsible for nosocomial infections. Alternative therapies, such as vaccines, are required to decrease the world’s reliance on antimicrobial agents. Specifically, glycoconjugate vaccines such as those used against Haemophilus influenzae B, Streptococcus pneumoniae, and Neisseria meningitidis are used globally and are highly effective. These vaccines consist of an antigenic bacterial glycan bound to a carrier protein. The glycan is usually a capsular polysaccharide (CPS), however, the notion …

The Coralhydro2k Database: A Global, Actively Curated Compilation Of Coral Δ18o And Sr/Ca Proxy Records Of Tropical Ocean Hydrology And Temperature For The Common Era, Rachel M. Walter, Hussein R. Sayani, Thomas Felis, Kim M. Cobb, Nerilie J. Abram, Ariella K. Arzey, Alyssa R. Atwood, Logan D. Brenner, Émilie P. Dassié, Kristine L. Delong, Bethany Ellis, Julien Emile-Geay, Matthew J. Fischer, Nathalie F. Goodkin, Jessica A. Hargreaves, K. Halimeda Kilbourne, Hedwig Krawczyk, Nicholas P. Mckay, Andrea L. Moore, Sujata A. Murty, Maria Rosabelle Ong, Riovie D. Ramos, Emma V. Reed, Dhrubajyoti Samanta, Sara C. Sanchez, Jens Zinke

Faculty Publications

The response of the hydrological cycle to anthropogenic climate change, especially across the tropical oceans, remains poorly understood due to the scarcity of long instrumental temperature and hydrological records. Massive shallow-water corals are ideally suited to reconstructing past oceanic variability as they are widely distributed across the tropics, rapidly deposit calcium carbonate skeletons that continuously record ambient environmental conditions, and can be sampled at monthly to annual resolution. Climate reconstructions based on corals primarily use the stable oxygen isotope composition (δ18O), which acts as a proxy for sea surface temperature (SST), and the oxygen isotope composition of seawater (δ18Osw), a …

Progress Toward A Comprehensive Model For Mass Transfer In Structured Packings, Jack Wilfert, Brian F. Hanley

Faculty Publications

Significant effort has been devoted to the study of mass transfer in sheet metal structured packings over the past half century. A number of mass transfer correlations have appeared in the literature as a result of those efforts. Unfortunately, none of these correlations has shown itself to be reliable over the full range of chemical systems, column operating conditions, and packing topologies encountered today. In an attempt to rectify some of the shortcomings of earlier correlations for sheet metal structured packings, we have employed a new data analysis methodology which simultaneously fits «HETP»data and mass transfer area data. The correlation …

Coral Reproduction In The Equatorial Eastern Pacific: Reproductive Trends And Seasonal Parameters, Susan Beth Colley

LSU Doctoral Dissertations

Most equatorial eastern Pacific (EEP) corals can reproduce year-round (Glynn et al. 1991, 1994, 1996, 2000, 2008, 2011, 2012, Colley et al. 2000). Gamete development occurs in several cycles throughout the year with a variable number of maturation cycles and presumably spawning events. The length of the breeding seasons in these corals is species-specific and can be locale-specific. The long-term reproductive dataset of these prior studies was utilized for Diaseris distorta, Pavona gigantea and Psammocora stellata (Colley et al. 2000, Glynn et al. 1996, 2012). Gametogenic trends are investigated in association with seasonal change of several environmental variables in …

Roleplaying Games And Performance, Benjamin Joseph Munise

LSU Doctoral Dissertations

Roleplaying Games and Performance calls to mind popular appearances of roleplaying games on stage and screen, like Stranger Things or Qui Nguyen’s popular play, She Kills Monsters. However, inquiry into the way roleplaying games appear in these titles reveals the way they have been instrumentalized to serve the ends of their respective mediums. Scholars writing about roleplaying games also tend to leap straight to analyses of video games, with many words spilled over World of Warcraft while a live site of analog performance sits before them. In this work, I address the tabletop roleplaying game as a medium with …

Confirmatory Factor Analysis Of The Adult Coping Inventory, Kristen Ashley Hollas

LSU Doctoral Dissertations

There are few psychometrically sound measures that assess coping in adults. For example, a widely used measure of coping, the COPE, has highly unstable sub-scales and was developed using a homogenous sample (Lyne & Roger, 2000). Because of these limitations, the Adult Coping Inventory (ACI) was developed. The ACI is a 57-item measure that contains five factors including Problem Solving, Mindfulness, Maladaptive Coping, Social Support and Avoidance. Initial reliability and validity analyses demonstrate good construct, concurrent and incremental validity. The current study involved conducting a confirmatory factor analysis to confirm the factor structure of the ACI. The participant sample consisted …

Experiments And Data Analysis For Modulated Phase Gratings In X-Rays, Sydney B. Carr

LSU Master's Theses

Purpose: Modulated Phase Grating (MPG) interferometry has been shown in theory and simulations to produce observable fringes on a clinical detector without requiring fluence absorbing analyzer. In this work, we will experimentally show that the MPG X-ray system produces observable fringes and multi-modal X-ray images.

Motivation:Nearly 1 in 8 women in the US will develop invasive breast cancer in their lifetime, accounting for approximately 40,000 deaths each year [1-2]. In order to pursue the best treatment option available, cancer itself must be adequately imaged and staged, based on size and level of metastasis, on the order of Stage I-IV. …

The Effectiveness Of Eye-Hand Coordination Training In Virtual Reality, Kelley Burger

LSU Doctoral Dissertations

Virtual environments (VE) and virtual reality (VR) through head-mounted displays (HMD) have been used to test and train eye-hand coordination skills in a way that is more immersive than traditional 2D video training. As this technology continues to evolve, researchers have sought to determine the degree to which these new technologies can augment training. This research attempts to expand the literature on sport skill training in VE and VR to elucidate the training protocols that support learning. The first study was designed to determine how a single session of occlusion training would affect football catching skills in VR. While adding …

Reducing Recycling Contamination Using An Information Nudge, Mimi Rivette

LSU Master's Theses

Recycling contamination is a central challenge to recycling programs but is infrequently studied due to the difficulty of measuring contents and the inconvenience of sorting through recycling bags by hand. We conducted two simultaneous experiments to address both the issue of recycling contamination and the infrequency of its study at Louisiana State University in Fall 2021. We implemented two signage treatments, the first explicitly instructing passersby not to recycle a short list of common recycling contaminants, including Styrofoam, food wrappers, plastic bags, and face masks, and the second generally encouraging recycling but excluding specific instructions on what to recycle. To …

Remote Sensing And Artificial Intelligence-Based Modeling And Prediction Of Harmful Algal Blooms In Lake Pontchartrain, Ian Smith

LSU Master's Theses

Harmful Algal Blooms (HABs) and particularly toxic cyanobacterial harmful algal blooms (CyanoHABs) have become a growing threat to the environment, economy, communities, and human and animal health. This is particularly true for Lake Pontchartrain. Forecasting the occurrence of cyanobacterial HABs in Lake Pontchartrain is a process that currently does not exist, as nowcasting by the NCCOS Algal Bloom Monitoring System or the similar system implemented by the U.S. EPA is currently the only method to monitor HAB production in the Lake. This thesis made this process possible by identifying antecedent environmental conditions controlling CyanoHABs, describing the conditions using NASA satellite …

Reconstruction Of Volumetric Modulated Arc Therapy-Computed Tomography, Chia-Lung Chien

LSU Doctoral Dissertations

Purpose: Volumetric modulated arc therapy-computed tomography (VMAT-CT) was proposed in 2010 as the CBCT reconstruction technique using portal images collected during VMAT. Yet, its clinical applications were impeded by the poor image quality due to motion blurs from fast movements of multi-leaf collimator (MLC) and projection data deficiency due to truncations from MLC. The goal of this study is to develop systematic preprocessing methods, and a novel iterative reconstruction algorithm to generate quality VMAT-CT and lower the number of failure cases of VMAT-CT reconstruction.

Methods: Systematic image preprocessing methods, including Online region-based active contouring (ORACM), MLC motion modeling and outlier …

Ross Sea Ocean-Temperature Reconstruction And Marine Radiocarbon Reservoir Effect Calibration From Modern And Pre-Modern Scleractinia, Colby Knight

LSU Master's Theses

Warm Circumpolar Deep Water (CDW) upwelling in the Southern Ocean currently circulates underneath Antarctic ice shelves in many areas. The associated melting reduces the ice-shelf buttressing effect, which can subsequently accelerate flow and cause retreat of grounded and floating ice. Upwelled CDW may have also been a primary driver of post-Last Glacial Maximum (LGM) deglaciation, but there are few proxy data from which upwelling history and paleo-ocean temperatures can be reconstructed. Here we build on previous deep, cold-water coral studies (e.g., Stewart et al., 2020) to detect CDW intrusion on the western Ross Sea continental shelf using lithium-to-magnesium ratios (Li/Mg) …