Life Sciences Commons^™

Preliminary Analysis Of Identifying Microplastic Polymers Using Ftir Spectroscopy From Surface Waters In The Pacific Northwest, Hannia Larino

Environmental Science Undergraduate Theses

Microplastics (MP) are synthetic polymers < 5 mm in length. They have been found in a range of aquatic environments and inside the organs of human and aquatic species. There have been a number of studies surveying waterways for MP presence and abundance using microscopic analysis, however there is limited research findings on MP polymer identification. For this project, surface water samples were collected from 5 sites in the Pacific Northwest, extraction was done using wet peroxide oxidation, and Fourier Transformed Infrared (FTIR) spectroscopy was used to identify the polymers. Microplastics were found at all 5 sites, with the dominant polymer being polyethylene (> 65%), fragment was the most common morphology (> 74%), black was the most common color (≥ 33%), and the most common lengths were below 1 mm (>50%). Understanding the MP composition in surface waters can help direct policies related to reduction of plastic pollution in aquatic environments. Furthermore, knowing the chemical composition of polymers can help researchers understand how MPs influence the physiology and ecology of biota. Future research should investigate if spatiotemporal variables influence the results.

A Comparison Of Diploid And Triploid Eastern Oysters For Aquaculture Production Under Extreme Temperatures And Salinities, Joshua H. Kim

LSU Master's Theses

Off-bottom aquaculture of Eastern oysters (Crassostrea virginica) is a nascent industry that is increasingly supported by the use of triploid oysters, which grow faster than diploids. Despite their growth advantage, elevated triploid mortality compared to diploids under high temperature, low salinity, or a combination of these conditions challenge consistent triploid production. Identifying the environmental thresholds at which differential triploid mortality occurs and predicting its economic impact are important to informing decision-making in oyster aquaculture. The goal of this thesis was to compare the biological and economic performance of diploid and triploid oysters under high temperature and low salinity conditions. …

A Comparative Analysis Of Extant Oceanic Shark Species Using Trait-Based Ecology, Elizabeth A. Johnson

All HCAS Student Capstones, Theses, and Dissertations

Over the past few decades, scientists have been working together to mitigate human impacts on global shark populations, but deciding which species need the most immediate attention can be difficult. This study uses a newly emerging approach to ecology, trait-based ecology, to identify trends in trait expression with depth and determine which species have the most unique sets of traits. While trait-based ecology has already been applied to numerous fields, a trait-based approach to shark research is still in its infancy. A total of 15 traits across 337 oceanic shark species were examined to identify trends in trait expression and …

The Effects Of Simulated Predation And Nursery Structure On Post-Outplant Survival And Growth Of Sexual Juveniles Of Six Caribbean Coral Species, Jarrod Little

All HCAS Student Capstones, Theses, and Dissertations

Over the past few decades, increasing frequency and severity of direct and indirect anthropogenic stressors have resulted in reef degradation and decreased coral cover and diversity. In South Florida, coral propagation ex situ has gained popularity as a means to restore coral cover. Outplanting sexually propagated corals on the reef is particularly important as it contributes to greater genetic diversity and potentially overall reef resilience. However, these corals typically experience high levels of predation following outplanting, significantly reducing coral survival, and thus constitute a major bottleneck to the success of restoration efforts. This study assessed if simulated predation events on …

Assessment Of Enzyme Stability In Subsurface Sediments By Computational Methods, Kambiz Kalhor

Masters Theses

The microorganisms found in marine subseafloor sediment play a vital role in global carbon and nitrogen cycles, with an estimated 2.9×10²⁹ cells, accounting for about 0.6% of Earth’s total living biomass. These microbes grow at a very slow rate, with carbon turnover occurring over the course of years to thousands of years, about six orders of magnitude slower than sulfate reducing bacteria in pure culture. These slow metabolic rates suggest that the enzymes they produce must also have extended lifespans in order to be effective over such long periods of time. As a result, these enzymes are likely to …

Observing The Response Of The Caspian Sea Microbiome To Crude Oil Amendment Under Oxic And Hypoxic Conditions, Zabrenna Georgiana Griffiths

Doctoral Dissertations

The Caspian Sea is the world’s largest landlocked saline lake positioned between Europe and Asia and for its historic and large-scale oil reserves. These vast oil reserves have led to the development of an intricate network of pipelines, and drilling operations causing the environmental deterioration of the waterbody. Drainage from surrounding river basins brings an influx of pollutants from residential, industrial and agricultural origins which further compounds this issue. The endorheic nature of this waterbody causes the retention and accumulation of these pollutants, ultimately reducing water quality.

The increased nutrient input has steadily intensified eutrophication in this waterbody resulting in …

Biometric Assessment Of Spotted Seatrout (Cynoscion Nebulosus) From Recreational And Commercial Fisheries In Mississippi, Usa, Nimah Folake Osho-Abdulgafar

Master's Theses

Quantitative stock assessments for Mississippi’s Spotted Seatrout use length-, age-, and sex-composition data from fishery-independent sources as proxies to estimate biostatistical characteristics of fisheries harvests due to lack of sector-specific data. In Chapter 2, I examined the age, length, and sex composition of Spotted Seatrout from three fishery-dependent sectors. Between April and December 2023, I collected 210 fish (n = 19, 124, and 67 from private, charter, and commercial sectors, respectively). The length ranged between 373-535mm, 285-523mm, and 345-568mm TL, with mean ± SD lengths of 453 ± 51mm, 393 ± 57mm, and 442 ± 53mm TL, respectively. Age ranged …

Impact Of Thermal-Hydric Stress Of Physiological Performance And Mating Behavior Of Fiddler Crabs, Talene G. Yeghissian

Dissertations

Fiddler crabs live on the edge of their thermal tolerance limits, balancing the need to thermoregulate with the need to mate. Previous research suggests that increased temperature reduces fiddler crab surface activity time, thus decreasing mating opportunities, throughout the range species with greatest impacts to low latitude populations. The less studied missed mating opportunities associated with behavioral compensation for thermal stress are crucial to understanding species vulnerability to climate change. In this dissertation, I describe a combination of experimental and observational approaches in the field and in the laboratory to investigate the physiological and behavioral responses of fiddler crabs to …

Using Unmanned Aircraft Systems (Uas) To Assess Body Condition Of Common Bottlenose Dolphins (Tursiops Truncatus Truncatus) In The Indian River Lagoon, Florida, Jessica Jane Provenzano

Theses and Dissertations

Common bottlenose dolphins (Tursiops truncatus truncatus) in the Indian River Lagoon (IRL) have experienced four Unusual Mortality Events (UMEs). This stock is considered immunocompromised and is routinely subjected to persistent anthropogenic stressors such as fishing gear entanglement, vessel strikes, contaminants, and harmful algal blooms. Previous body condition assessments of this stock have involved invasive capture-release examinations or subjective methods using lateral body images. To improve precision, we investigated the use of photogrammetry data collected from noninvasive unmanned aircraft systems (UAS) combined with models developed from capture-release data to estimate morphometric parameters and subsequently determine the body condition of …

Prochlorococcus Death By A Ubiquitous Zooplankton Filter Feeder, Avery Harman

University Honors Theses

Prochlorococcus is a globally abundant cyanobacterium that can help reveal the ecology of microorganisms in the ocean. Specifically, mortality by zooplankton such as appendicularians is globally important and Prochlorococcus can help reveal some of the choices made around feeding for this ubiquitous filter feeder. Two ecotypes of Prochlorococcus were introduced to appendicularians to determine if appendicularian feed selectively between these ecotypes. Further, a single ecotype of Prochlorococcus was fed to appendicularians over a variety of life stages to determine if retention rate changed with appendicularian life stage. My results reveal that there is no significant selection between the two Prochlorococcus …

Investigating The Regulation Of The Hypothalamic-Pituitary-Interrenal Axis In Atlantic Sturgeon (Acipenser Oxyrinchus) Following An Acute Stressor, Liam Doherty

Undergraduate Theses, Capstones, and Recitals

This study investigated the response to acute stress in Atlantic sturgeon (Acipenser oxyrinchus) and HPI axis regulation of glucocorticoid production during stress by examining the expression of key genes― corticotropin-releasing hormone (crh), corticotropin-releasing hormone receptor (crhr), proopiomelanocortin (pomca/pomcb), melanocortin 2 receptor (mc2r), and steroidogenic acute regulatory protein (star)―that are associated with hypothalamus/pituitary/interrenal (HPI) axis of bony fishes. Additionally, tyrosine hydrogenase (th1 and th2) and phosphoenolpyruvate carboxykinase (pepck), found in catecholamine-producing cells in the head kidney of the sturgeon, were investigated …

Beating The Heat: The Use Of Coral-Benefitting Bacteria For Heat-Stressed Anemones And Inspiring Future Biologists, Navah Eshraghi

Undergraduate Honors Theses

The warming of ocean temperatures has caused mass coral-bleaching events characterized by the expulsion of vital algal symbionts from coral tissues. However, the possibility of algal reuptake and existence of bacteria that support coral-algal symbiosis are two avenues of potential restoration efforts. Using the sea anemone Exaiptasia diaphana as a model for corals, I tested whether the coral-benefitting bacterium Endozoicomonas montiporae could enhance algal uptake under ambient (27°C) and heat-stressed (32°C) conditions. I then turned acquired results into an article modeled after National Geographic Kids to introduce the experiment to younger ages. While temperature was a larger determinant of algal-uptake …

Investigating The Characteristics Of Bacteria Isolated From The Sea Scallop (Placopecten Magellanicus) Larvae And Tanks, Ayodeji Olaniyi

Electronic Theses and Dissertations

Placopecten magellanicus, also known as the Atlantic deep-sea scallop, is a valuable marine species on North America's northeastern coast. Although adult scallops can be successfully bred in hatcheries, a perplexing and destructive event takes place during the last two weeks of larval development: a sudden and severe mortality event that causes a drastic decline in populations, with some reports suggesting that survival from egg to competent larva can sometimes be reduced to as low as 1-10% during a span of 48 hours. The precise reasons for larval mortality in sea scallops remain unclear. Prior studies have investigated infections in …

Predicting Larval Dispersal And Population Connectivity Of Sea Scallops (Placopecten Magellanicus) On The Maine Coast Through An Individual-Based Model, Kelsey M. Ward

Electronic Theses and Dissertations

A hydrodynamic model of the coastal currents in the Gulf of Maine has been adapted to include an individual-based scallop larval development and behaviors module and used to estimate sea scallop (Placopecten magellanicus) larval dispersal along the eastern Maine coast. Larvae are released along the coastline out to a 40 m isobath during September and October, and dispersal is driven using the hydrodynamical model result for the region from 2014 through 2017. The origins of particles that “settle” in focal areas, such as Blue Hill Bay, Jericho Bay, and Narraguagus Bay, are determined from model runs, and the …

Investigation On The Effects Of Biofouling On The Boundary Layer, Adam N. Bacon

University of New Orleans Theses and Dissertations

This study is an investigation of the effect of biofouling on the boundary layer of a flat plate and a NACA 4-digit series foil. Three identical hydrofoils made of resin were placed in the Gulf of Mexico at Grand Isle, Louisiana, and observed and analyzed by marine biologists at the University of New Orleans for their species composition. The resulting biofouling that grew was primarily made up of barnacles and bryozoans. The foils were submerged in an open channel flume at zero incidence and subjected to a series of experiments whose arc-length Reynolds numbers ranged from approximately 13000 to 32000. …

The Historical Biogeography Of Spiny Lobsters In The Genus Panulirus And The Influence Of Environmental Conditions On The Adaptive Evolution Of Mitochondrial Protein-Coding Genes In The Achelata, Alyssa Baker

All Theses

Contemporary and historical changes in marine environmental conditions influence biodiversity drastically. In marine invertebrates with highly dispersive planktonic larvae, diversification is facilitated or constrained by tectonic plate movements altering geography, prevailing current patterns, and climate. The decapod crustacean infraorder Achelata, which contains the spiny (fam. Palinuridae) and slipper (fam. Scyllaridae) lobsters, is characterized by a long-lived phyllosoma larvae stage. Panulirus is the most economically significant and speciose genus of spiny lobsters, with 20 recognized extant species and 5 subspecies distributed throughout shallow tropical and subtropical oceans worldwide. Diversification within these lineages has been proposed to be primarily driven by geological …

Response Of Fish Assemblages To Increased Connectivity And Habitat Restoration In Bayou St. John, A Degraded Waterway In New Orleans, La, Alia Jones

University of New Orleans Theses and Dissertations

Bayou St. John is a degraded waterway located within the City of New Orleans. The Bayou, which is disconnected from Lake Pontchartrain by floodgates, has undergone restoration efforts to improve connectivity through frequent floodgate openings and marsh habitat restoration outside of the floodgates. To assess possible responses of local fish assemblages to these restoration efforts, I analyzed long-term fish assemblage data from three sites located inside of the floodgates and one site located at the restored marsh outside of the floodgates. Two sites inside of the floodgates experienced significant changes in assemblages between the pre-opening period (2006-2012) and post-opening period …

Effects Of Dissolved Oxygen And Ph On Eastern Oyster (Crassostrea Virginica) Growth, Karina D. Ledezma

Honors Theses

Coastal ecosystems, known for their abundant natural resources and role in environmental processes, are facing challenges posed by climate change, pollution and anthropogenic activities. Among these challenges is the expansion of hypoxic zones, characterized by low dissolved oxygen (DO) levels, which poses a significant threat to benthic organisms and oyster fisheries. This research investigates the interaction between hypoxia and pH dynamics, intensified by freshwater input, and the biomineralization of Eastern oysters (Crassostrea virginica). To explore these dynamics, experimental trials were conducted in 24 tanks, simulating normoxic, hypoxic, and fresh hypoxic conditions, to assess the impact of hypoxia on …

Trophic Ecology Of Black Swallowers (Scombriformes: Chiasmodontidae: Chiasmodon) In The Deep-Pelagic Gulf Of Mexico, Travis J. Kirk

All HCAS Student Capstones, Theses, and Dissertations

The ecology of deep-pelagic predatory fishes remains poorly understood despite their importance as ecosystem regulators and energy transfer vectors. This study investigated the trophic ecology of three species of the predatory fish genus Chiasmodon (“black swallowers”) in the Gulf of Mexico, a region that serves as an analog for the global low-latitude deep pelagial, the world’s largest cumulative ecosystem. Foraging habits (e.g., selectivity, chronology, daily ration) of an “advanced” evolutionary fish in a system that is otherwise dominated by basal fish taxa, were quantitatively estimated via high-resolution stomach content analysis. A quantitative dataset of both predator and prey abundance, the …

Euhaplorchis Sp. A Effect On Social Behavior And Familiarity Of Gulf Killifish (Fundulus Grandis), Hannah Bauman

All HCAS Student Capstones, Theses, and Dissertations

Trophically transmitted parasites may manipulate their hosts’ phenotype (e.g., behavior, physiology, morphology) to increase the likelihood of transmission to the definitive host. In fishes, stable social groups develop familiarity over time through repeated interactions among individuals, and social preferences are often developed due to familiarity. Consequently, fishes often shoal with familiar fishes, a behavior that is likely to be protective against predation. Parasites may alter fish social dynamics in two ways: by decreasing association with familiar individuals, thereby isolating infected fish and making them more susceptible to predation by definitive hosts; and/or by incentivizing uninfected individuals to avoid infected fish …

Microplastic Quantification On The Effect Of Endoparasite Communities In Florida Seabirds, Sarah N. Prieto

All HCAS Student Capstones, Theses, and Dissertations

Microplastics are being studied in a variety of different projects to better understand their impact and threat to wildlife species. Although there is an understanding that microplastics are affecting our wildlife, there are still questions about how coastal seabirds come to ingest them and how the ingestion is altering critical biological processes, such as that for endoparasite communities. This project aims to determine a better understanding of two main objectives: assessment of the presence of secondary ingestion of microplastics in coastal seabirds due to the fish species they prey on and relationship between microplastics and endoparasite communities' structure and state …

Addition And Subtraction: Coral Reproduction And Disease In A Changing Ocean, Ashley Rossin

LSU Doctoral Dissertations

Marine diseases are changing the landscapes of coral reefs particularly throughout the Western Atlantic. Stony coral tissue loss disease (SCTLD) swept through this region impacting at least 22 stony coral species. White plague (WP) is a more ephemeral disease, but still has a significant impact on coral reef health and perseverance, especially under a changing ocean. While these impacts are seen on the reef-scale, we can zoom into the tissue-level to identify disease markers for both diseases and identify their differences. This has ramifications for disease intervention, as well as mitigation strategies. Despite continuous disease outbreaks, healthy corals persist and …

Maneuverability Of Cuttlefish And Squid: An Integrated Kinematic And Hydrodynamic Analysis, Alissa Marie Ganley

Biological Sciences Theses & Dissertations

Turning is important for life underwater, playing roles in predator avoidance, prey capture, locomotion, and communication. While turning abilities have been explored in many taxa, little is known about maneuverability of cephalopods, such as cuttlefishes and squids. The objectives of this dissertation include: (1) quantifying the turning abilities of cuttlefish hatchlings and determining whether there are species-specific differences; (2) examining the turning capabilities of adult cuttlefishes, with the goal of comparing adult performance with that of conspecific hatchlings; and (3) quantifying how adult neritic squids perform turns to provide a broader context of maneuvering strategies in cephalopods. To investigate turning, …

Time Series Modeling To Ascertain Age In Fisheries Management, Kathleen Sue Kirch

OES Theses and Dissertations

The ability to assign accurate ages of fish is important to fisheries management. Accurate ageing allows for the most reliable age-based models to be used to support sustainability and maximize economic benefit. Structures used to age include bones, scales, and most commonly ear bones (otoliths). Assigning age relies on validating putative annual marks by evaluating accretional material laid down in patterns in fish otoliths, typically by marginal increment analysis. These patterns often take the shape of a sawtooth wave with an abrupt drop in accretion yearly to form an annual band and are typically validated qualitatively. Researchers have shown keen …

Quantifying The Respiratory Plasticity Of Common Fishes Of The Indian River Lagoon, Logan Exton

Honors Theses

Increasing water temperatures resulting from global climate change introduce new energetic demands for marine organisms. Higher energy input will be required to cope with a subsequently higher metabolic rate, affecting all aspects of an individual’s life and therefore their survival. Because estuaries act as a link between rivers and oceans, they and their inhabitants are considered to be the most threatened by climate change. Therefore, it is crucial to understand how these organisms will respond to increased stressors due to climate change. Checkered pufferfish (Sphoeroides testudineus) are among the most common teleost fish in the Indian River Lagoon, …

Considering Tidal Flooding To Provide A Holistic Approach To Nutrient Input Management, Mary Beth Armstrong

Dissertations, Theses, and Masters Projects

This report explores the integration of tidal flooding impacts into nutrient management frameworks for the Chesapeake Bay, a potentially large gap in current strategies. Coastal communities in the Chesapeake Bay, face an increasing threat from tidal flooding—also known as sunny-day flooding—which occurs without rainfall. In 2023, Norfolk, Virginia experienced 10 days of tidal flooding, but forecasts indicate that by 2075 the area could be experiencing tidal flooding every day. Recent research highlights that even a single tidal flooding event can introduce substantial nutrient loads into the Bay, sometimes exceeding the annual nutrient allocations. This significant increase in both the frequency …

Monitoring Faunal Responses To Biodegradable Oyster Reef Restoration Materials With Camera Traps, Tara L. Blanchard

Honors Undergraduate Theses

Restoration of the oyster reefs has become increasingly crucial due to great population declines around the globe. Intertidal oyster reefs provide essential foraging and loafing grounds to many faunal species, including several threatened/endangered wading bird species. Biodegradable oyster reef restoration materials have been introduced to avoid potential plastic pollution from traditional materials. Studies have shown success regarding oyster recruitment rates to these materials. However, their impacts on fauna using restored oyster reefs are unknown. This project aims to evaluate oyster reef restoration using biodegradable materials to increase faunal diversity, abundance, and foraging behaviors. Camera traps were deployed to observe fauna …

Density Dependent Calling Behavior In North Pacific Humpback Whales, Lucas J. Anderson

Honors Theses and Capstones

Animal density can define factors such as mating success, food acquisition, and communication. Inferring animal density from vocal rates is an important tool for estimating abundance and space use in difficult-to-study species like marine mammals and requires an understanding of the relationship between social context and calling rates. The goal of this project was to investigate the relationship between animal density and call rate in Southeast Alaskan humpback whales (Megaptera novaeangliae). Passive acoustic monitoring data were collected along with visual observations gathered near Frederick Sound and Stephen’s Passage, Southeast Alaska, over two summers (2019, 2022). Observers watched whales …

Characterizing The Habitat Use Of Pacific Coast Feeding Group Gray Whales (Eschrichtius Robustus) And The Spatial And Temporal Variability Of Their Benthic And Planktonic Invertebrate Prey In Northern California, Robyn E. Norman

Cal Poly Humboldt theses and projects

As opportunistic foragers, the Eastern North Pacific population (~20,000) of gray whales (Eschrichtius robustus) feed on diverse benthic and planktonic invertebrates in northern Alaska foraging grounds before they undertake one of the largest yearly migrations of any mammal to breed in Baja California, Mexico. While most of the population travels to the summer foraging grounds in Alaska, a sub-group of whales (~230) called the Pacific Coast Feeding Group (PCFG) summer between British Columbia, Canada, and northern California. The diet of PCFG whales typically includes high-density and/or high-caloric prey items like mysids and diverse species of amphipods, yet a …

Mitochondrial Adaptation In The Green Crab Hybrid Zone Of The Gulf Of Maine, Jared Lynch

Honors Projects

The mitochondrial genome has historically been relegated to a neutral genetic marker, but new evidence suggests mitochondrial DNA to be a target for adaptation to environmental stress. The invasive European green crab (Carcinus maenas) exemplifies this in the Gulf of Maine’s hybrid zone, where interbreeding populations exhibit thermal tolerances influenced by mitochondrial genotype. To better understand the mechanism behind this phenomenon, the effect of mitochondrial genotype on mitochondrial activity was tested by measuring mtDNA copy number (mtCN) and the activity of complex I, II, and IV of the electron transport system via high-resolution respirometry. Mitochondria isolated from frozen …