Life Sciences Commons^™

Prochlorococcus Death By A Ubiquitous Zooplankton Filter Feeder, Avery E. 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 …

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 …

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. …

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 …

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 …

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 …

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 …

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, …

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, …

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 …

Investigation Of The Effects Of Ocean Acidification On Juvenile Homarus Americanus Feeding Behavior, Sophia Roy

Honors Theses and Capstones

Climate change has led to increased CO2 absorption by ocean surface waters, resulting in decreased pH levels, a phenomenon known as ocean acidification (OA). A primary class of marine organism behavior is impacted by OA, in particular, olfactory-mediated behaviors related to foraging and feeding success. However, the biological mechanisms responsible for the documented impairment of foraging and feeding-related behaviors remains in question. We find that juvenile American lobsters (H. americanus) exhibit significantly faster rates of total feeding times in response to short-term low pH exposure. However, total search time and total handling time were not affected by pH when examined …

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 …

Image Segmentation By Convolutional Neural Networks In Coral Resilience Research, Jennifer Benbow

Master's Projects

As ocean temperatures rise, coral bleaching is becoming more frequent and severe. Selective breeding experiments show promise for enhancing coral resilience, but scaling these projects is hindered by the labor-intensive nature of taking numerous time series measurements as corals grow. Automating this process with computer vision is one solution to this bottleneck, and to our knowledge, no such tool exists at present. To fill this gap, we have trained a set of machine learning models, based on the Mask R-CNN framework, for segmenting juvenile corals in lab-based coral resilience research. This work shows that retraining the Mask R-CNN architecture through …

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 …

Variation In The Fear Response Of Atlantic Sand Fiddler Crabs (Leptuca Pugilator) To Anthropogenic Disturbance, Katrina L. Buttram

Electronic Theses and Dissertations

Leptuca pugilator is a common inhabitant of southeast Georgia salt marshes. This study examined the boldness of Leptuca pugilator across environmental conditions and human impacts. Here, boldness was defined as time taken to reemerge from a burrow after a fear stimulus. I hypothesized that crabs would vary in their boldness based on their surroundings, reproductive timing, and sex. Field and experimental trials were conducted to isolate which factors most influence boldness. Field trials were conducted at four sites varying in human influence throughout the breeding season. During each survey, vegetation height, substrate temperature, average burrow width, burrow count, and distance …

To Hum Or Not To Hum: Analyzing And Provoking Sound Production In The American Lobster (Homarus Americanus), Renske Kerkhofs

Honors Projects

American lobsters (Homarus americanus) produce humming sounds by vibrating their carapace. These sounds have a fundamental frequency on the order of 100 Hz, with multiple higher harmonics. Though I found no relationship between lobster carapace length and hum frequency, I observed sounds similarly structured to hums but with frequencies an order of magnitude higher, suggesting that lobsters may use a wider range of sounds than previously thought. Using laser vibrometry, I was able to pick up high frequencies of carapace vibration that were similar to those I observed on sound recordings. Lobsters seem to hum most readily when …

Physiological Responses Of The American Lobster Cardiovascular System To Neuropeptide Sgrnflrfamide (Sgrn), Andre Eden

Honors Projects

During every second of a human’s life, the cardiovascular system is modulated by factors both intrinsic and extrinsic to the physiology of the heart. We can uncover new insights regarding the nature of our system through investigations of similar systems in other model species. One example materializes itself in the form of the American Lobster (Homarus americanus) whose single-chambered heart finds resemblance to the function and anatomy to that of humans. The lobster heart is powered by the cardiac ganglion (CG), a group of neurons that drive contractions of surrounding heart muscles, known as the myocardium. Both the …

The Influence Of Intracellular Photosymbiosis On The Evolution And Function Of Cnidarian Immunity, Madison A. Emery

Biology Dissertations

Intracellular photosymbiosis with Symbiodiniaceae is facilitated by cnidarian immunity as it is required for symbiont recognition and is subsequently suppressed to maintain stable intracellular symbiosis. To date, it is unclear how the cnidarian-Symbiodiniaceae symbiosis influences immune gene repertoires, immune gene expression, and disease pathology across its independent evolutions. To address these knowledge gaps, my dissertation approaches studying the cnidarian-Symbiodiniaceae symbiosis through a comparative lens to determine how it shapes immune gene evolution and immune responses in divergent symbiotic cnidarian species. In chapter two I survey eight non-symbiotic and seven symbiotic cnidarians proteomes for four families of pattern recognition receptors (PRRs) …

Tropical Fish Study In Tahiti, French Polynesia, Miranda Brainard, Caitlyn Swango, Paityn Houglan, Richard Londraville

Williams Honors College, Honors Research Projects

In May of 2023, I embarked on an exciting research journey to Moorea, French Polynesia, alongside fellow students and faculty members from the University of Akron and Syracuse University. This expedition was part of the university-sponsored Tropical Vertebrate Biology course, where we delved into the exploration of various tropical species inhabiting the island, including sea urchins, geckos, and my primary focus, the blackspotted rockskipper.

My research team, composed of my co-authors and me, was particularly intrigued by the unique refuge-seeking behavior displayed by blackspotted rockskippers. These amphibious fish are renowned for their remarkable ability to inhabit tide pools and rocky …

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 …

Habitat Utilization Of Marsh And Adjacent Submerged Landscape By Fish And Macroinvertebrates In A Gulf Of Mexico Tidal Oligohaline Environment, Tia Offner

Theses and Dissertations

Estuarine habitats are considered nursery habitats for fishes and invertebrates, but oligohaline environments are critically understudied. Using a seine net and fyke nets, we sampled Back Bay, Mississippi (USA), a low salinity estuary, once a month for a year to explore the temporal use of the marsh and adjacent submerged landscape by nekton species. We also looked at whether there is evidence of habitat preference in the most numerous nekton species. We used a novel habitat usage index (HUI) to compare seine and fyke net catches of our top 10 species, and evaluated catch size in relation to maturation size. …

Spawning Asynchrony Of The Endangered Acropora Cervicornis: Are Light Pollution And Abnormally Warm Temperatures The Culprits?, Krista Laforest

All HCAS Student Capstones, Theses, and Dissertations

The persistence of reefs relies on mature corals spawning synchronously to maximize fertilization and produce larvae to replenish local populations. Corals synchronize the release of gametes by responding to temperature, sun, and moon light cycles; however, abnormalities in these patterns can disrupt synchrony. This study is the first to describe regional asynchronous spawning of Acropora cervicornis by quantifying gamete development and spawning times among two reefs, an in situ nursery off Fort Lauderdale, and an in situ nursery in the Florida Keys. While A. cervicornis in the Florida Keys synchronously spawned within the predicted window of 2-5 days after the …

Evaluating Habitat Use By Nekton In Widgeon Grass (Ruppia Maritima), Shoal Grass (Halodule Wrightii), And Unvegetated Bottom Habitats In The Grand Bay National Estuarine Research Reserve, Jessica Woodall

Master's Theses

Seagrass beds support high biodiversity and animal abundance, serve as feeding grounds for a variety of animals, offer shelter from predation, and act as a nursery habitat for juveniles. The species composition of seagrass beds can impact their use as habitat by animals. Two common species of seagrass in the Gulf of Mexico are Ruppia maritima (widgeon grass) and Halodule wrightii (shoal grass). The shallow coastal waters of the Grand Bay National Estuarine Research Reserve (NERR) support both species, but the use of each seagrass as habitat by nekton is poorly understood, which can limit management decision-making. Nekton communities were …

Biophysical Factors Affecting Habitat Suitability For Crassostrea Virginica, Jason D. Tilley

Dissertations

Oyster reefs provide a variety of important ecosystem services. However, the mortality rate of eastern oyster, Crassostrea virginica, the dominant species that produces oyster reefs in the northern Gulf of Mexico, is increasing at an alarming rate due to a variety of abiotic and biological factors. I examined how biophysical factors, including the less-studied fatty acid profiles of the suspended particulate matter on which oysters feed, influenced morphometric condition of C. virginica.

I sampled suspended particulate matter (SPM) and oysters in-situ in the western Mississippi Sound, which historically supported the majority of oyster production in Mississippi waters. Sampling …

Fishing And Fear Effects Interact To Shape Herbivory On Coral Reefs, Bethany M. Tilton

All HCAS Student Capstones, Theses, and Dissertations

Predation influences animal behavior and shapes ecological structure and function through lethal effects and fear effects. On coral reefs, fear effects can alter the distribution and intensity of herbivory by herbivorous reef fishes. This includes the browsing functional group, which potentially reverses macroalgal phase shifts and promotes reef recovery. Herbivory by multiple functional groups may increase on coral reefs through the use of NTZs (no-take zones) but few studies have examined the extent to which small-scale NTZs (< 0.5 km²) influence fear effects and perceived predator presence on reefs. This study aimed to determine whether fear effects on browsers on …

A Rapid Site Selection Assessment As An Indicator Of Stony Coral Microfragment Outplant Success, John J. Alfirevich

All HCAS Student Capstones, Theses, and Dissertations

Microfragmentation of massive stony coral species is a technique being utilized to propagate corals asexually to help restore coral reefs. Microfragmentation consists of cutting corals into 3 cm diameter or less fragments, which boosts growth rates. However, in some locations the size of microfragments make them vulnerable to parrotfish predation and benthic overgrowth, reducing survival. As such, a method to identify key site characteristics which promotes microfragment outplant success, particularly one that can be performed quickly across multiple areas is needed. A rapid site assessment conducted prior to microfragment outplanting was performed at 12 randomly selected sites within the Kristin …

Psammocora Stellata Distribution At Devil's Crown, Floreana Island, Galápagos Islands, Ecuador, María José Guarderas Sevilla

All HCAS Student Capstones, Theses, and Dissertations

In the Galápagos Archipelago, the free-living nodular coral Psammocora stellata is a common species that does not form reef structures. However, it is a key component of the ecosystem by increasing habitat complexity and, consequently, species diversity. This species experienced a drastic decline in Devil’s Crown channel, Floreana Island, where it disappeared after the 1982-83 El Niño-Southern Oscillation, presumably by displacement of unattached colonies by strong surface waves and currents. This assemblage has now recovered to pre-impact levels. A combination of underwater photoquadrats from 2007 and 2009 and recent (2023) orthomosaics were used to determine changes in coral densities and …

Interactions Between Sediment Mechanical Structure And Infaunal Community Structure Following Physical Disturbance, William Cyrus Roger Clemo

<strong> Theses and Dissertations </strong>

Shallow, river-influenced coastal sediments are important for global carbon storage and nutrient cycling and provide a habitat for diverse communities of invertebrates (infauna). Elevated bed shear stress from extreme storms can resuspend, transport, and deposit sediments, disrupting the cohesive structure of muds, and sorting and depositing sand eroded from beaches. These physical disruptions can also resuspend or smother infauna, decreasing abundances and changing community structure. Infaunal activities such as burrowing, tube construction, and feeding can impact sediment structure and stability. However, little is known about how physical disturbance impacts short and long-term sediment habitat suitability and whether disturbance-tolerant infauna influence …