Abstracts of Poster Presentations
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Poster Abstracts
Urine protein composition of common bottlenose dolphins (Tursiops truncatus) from the Gulf of Mexico, USA.
Cusick, KN (GPMB, University of Charleston, SC)
Urinary proteins often serve as biomarkers for detecting renal issues in human and domestic veterinary medicine, but studies are lacking in marine mammal medicine. The urine proteome of wild bottlenose dolphins (Tursiops truncatus) will be investigated for the first time to describe variation in protein composition across two Gulf of Mexico populations (Sarasota Bay, FL and Barataria Bay, LA). The present study aims to examine correlations among urinary protein profiles and serum chemistry values, urine osmolality, age, and health status. I will test two hypotheses: 1) urinary protein composition will remain consistent across populations despite geographical distinctions, and 2) antimicrobial proteins will be amongst the most abundant proteins, like California sea lions (Zalophus californianus). Fifteen urine samples from bottlenose dolphin capture-release health assessments were proteolytically digested, and the resulting peptides will be analyzed by nano LC-MS/MS. On average, the Barataria Bay population exhibited significantly higher urine osmolality (1.3-fold) and protein concentration (5.2-fold) than the Sarasota Bay population (p<0.05). These differences could be attributed to the population’s dietary preferences and health status. Following protein identification, the top 30 proteins will be ranked according to an exponentially modified protein abundance index. These significant proteins will undergo ontology searches, essentially “humanizing” them for further assessment of function, origin insights, and comparative analysis across urine proteomes of different mammalian species. Establishing a urine proteome for bottlenose dolphins will serve as a reference point, facilitating the identification of potential markers that can be employed to monitor and evaluate renal health status in these marine mammals.
Characterization of Phthalate Metabolites in the Blubber of Common Bottlenose Dolphins (Tursiops truncatus) in Sarasota Bay, FL, USA.
Knight, MA (GPMB, University of Charleston, SC)
Phthalates are plasticizing chemicals added to a variety of consumer products. They are endocrine disrupting chemicals that can adversely impact mammalian development, reproduction, and metabolism. Phthalates are not chemically bound to the products to which they are added, enabling environmental exposure to humans and wildlife. In fact, phthalates have been detected in air, drinking water, natural water bodies and soil. Recent studies in bottlenose dolphins (Tursiops truncatus) have demonstrated prevalent exposure to phthalates, but current detection methods rely on urine samples collected during capture-release health assessments, which are logistically complicated and require physical handling of animals for sample collection. This study developed protocols for phthalate ester metabolite (mPAE) detection in bottlenose dolphin blubber. Utilizing solid phase extraction, high-performance liquid chromatography-tandem mass spectrometry, and blubber samples from dolphins stranded near Charleston, SC, a method was developed to extract and quantify phthalates in bottlenose dolphin blubber. This method will be utilized to determine if blubber mPAE concentrations correlate with urinary concentrations of Sarasota Bay bottlenose dolphins so that blubber may be used as an additional tissue for phthalate exposure surveillance in the future. Phthalate metabolite detection in blubber will provide another surveillance tool that is not limited to yearly health assessments because blubber samples can be taken via remote biopsy during smaller research operations. By standardizing methods for mPAE detection in bottlenose dolphin blubber, the geographic scope of exposure surveillance can expand to areas where animals are particularly at risk of exposure and corresponding adverse health effects (e.g., urban estuaries, developed coastlines).
Ecophysiology & water quality characterization of aquaculture and in situ macroalgae in Charleston Harbor, SC, USA.
Carbon, CJ (GPMB, University of Charleston, SC)
Charleston Harbor is home to a diverse and under-studied flora of macroalgae. Native macroalgae have great economic potential as sources of food, novel industrial products, biomedical compounds, and as tools for water quality bioindicators and wastewater management. Sea lettuce (Ulva spp.) and graceful redweed (Gracilaria tikvahiae) are abundant in the Charleston area and have been used extensively in aquaculture. Thus, the proposed study will use wild-harvested and aquaculture-raised Ulva spp, and G. tikvahiae as target species to assess their safety for local human consumption, and their potential as bioindicators of long-term water quality. Monthly sampling of algal specimens will occur at three field locations and one aquaculture facility. Monthly sampling will consist of collecting abiotic water quality data, assessing macroalgal physiology via Junior Pulse Amplitude Modulated Fluorometry, and bacterial assays to quantify the abundance of fecal coliform bacteria and Vibrio parahaemolyticus. Additionally, macroalgal tissue will be processed for stable isotope analysis (δ15N), nutrients, and heavy metal content. These data will fill the knowledge gap of ecophysiology of macroalgae in the southeastern United States and elucidate seasonal trends of water nutrients and bacterial abundance in Charleston Harbor. Data obtained from macroalgal tissue nutrient analyses will characterize any potential benefits of utilizing Harbor-grown macroalgae as a sustainable source of carbohydrates, lipids, and protein in a normal diet.
Understanding the Role of Substrate Complexity on Community Composition from Customized Marine Settlement Tiles in Charleston Harbor, SC.
Ware, R (GPMB, College of Charleston, SC)
Biofouling, or the settlement of epifaunal organisms on anthropogenic structures, is seen as a nuisance and can promote the spread of invasive species. This issue is exacerbated by current maritime structure design, which favors flat, smooth surfaces easily proliferated either by invasive species, or a low diversity of organisms. It has been demonstrated that complex artificial structures support diverse arrays of suspension feeders, which support small microcosms of their own and provide ecosystem services. By creating features on or within the surface of a structure, different groups can better recruit and proliferate. It is hypothesized that motile community, as well as sessile epifaunal community diversity and composition will differ among treatments varying in complexity. Artificial substrate panels will be created using 3D-printed material, at three levels of complexity treatments, using canyon structures as a proxy for complexity. One panel of each treatment will be arranged on a PVC frame, grouping them together for ease of retrieval. Three sites around Charleston Harbor, SC, will be selected for the deployment of six frames each from fall-winter and spring-summer. Units will be monitored twice monthly, with photographs and water samples collected. At the end of each deployment period, panels and associated motile fauna will also be collected for lab ID/analysis. Percent cover, diversity, evenness, and richness will be determined and compared across each treatment type. While understudied, the influences of substrate complexity on settlement may be broad and can be selectively used to create communities more resistant to disturbance.
Characterizing the influence of temperature on microplastic uptake and depuration in Eastern oysters, Crassostrea virginica.
Jones, GN (GPMB, College of Charleston, SC)
Microplastics are a contaminant of emerging concern in the marine environment due to the ease of their uptake by organisms. Filter feeders are especially at risk, as they must intake particulate matter to feed and can therefore easily ingest microplastics. In oysters, microplastic ingestion is known to have negative impacts on survival and reproduction. It is thus far unclear how multiple stressors in the face of anthropogenic climate change, such as high water temperature, may affect the uptake and depuration of microplastics in oysters. The objective of this study is to characterize the influence of temperature on the uptake and depuration of microplastic in Eastern oysters, Crassostrea virginica. Oysters will be collected from the Folly River, acclimated to laboratory conditions, and exposed to microplastics (5000 particles/L) at one of three temperatures (20°C, 24°C, or 28°C) and sampled at 0, 24, 48, or 96 hours to assess microplastic concentration and uptake. Individuals remaining after 96 hours will be transferred to microplastic-free seawater at the same temperature to depurate. During depuration, oysters will be sampled at 24, 48, and 96 to assess microplastic concentration. Microplastic concentration in each individual oyster will be assessed by counting the number of particles after digestion of tissues in 10% KOH and subsequent filtration. The results of this study will quantify the impact of temperature on the toxicokinetics of microplastics in oysters and therefore elucidate the risk that these potentially confounding stressors may pose to the oysters and the humans who consume them.
Exploring Spatial Isotopic Variations in Carbon and Nitrogen Isotopes of Reef-Associated Fishes in the Southeastern USA: A Path to Dynamic Environmental Modeling.
Kyridis, D (GPMB, University of Charleston, SC)
Isoscapes, spatial maps of variations in isotopic ratios, are an important baseline in understanding and utilizing Stable Isotope Analysis in ecological research. The objective of this project is two-fold. First, we will establish an isoscape of trends in δ13C and δ15N in reef-associated consumers of the Southeastern United States South Atlantic (SEUSA). Second, we will correlate the observed values with environmental parameters for the creation of generalized, predictive models for each element. 173 samples of Balistes capriscus (Gray Triggerfish, Family Balistidae) and 204 samples of Haemulon aurolineatum (Tomtate, Family Haemulidae) were collected during routine fisheries monitoring in continental shelf waters from Cape Hatteras to Cape Canaveral. A small sample of muscle from the left side of each fish was cleaned, dried, and homogenized to be analyzed for δ13C and δ15N values with an Elemental Analyzer Isotope Ration Mass Spectrometer at the Skidaway Institute of Oceanography. The data will then be appropriately corrected for lipid concentration and/or ontogenetic shifts. Geospatial interpolation (Kriging) will be used on the averaged data from each species at each station to investigate the patterns of the isotopic ratios in space. Lastly, the established patterns will be correlated with publicly available environmental data to create generalized models for each element that can be used in a variety of isotopic studies.
Understanding phytoplankton community composition in Charleston Harbor, South Carolina, USA using a multi-method approach.
Sonnenfeld, MG (GPMB, University of Charleston, SC)
Phytoplankton are an essential part of global freshwater, marine, and estuarine systems. In addition to being responsible for nearly all oceanic primary production, they are essential components of biogeochemical cycling and important indicators of ecosystem health. Many methods have been used to assess phytoplankton community composition (PCC), including traditional microscopy, photosynthetic pigments measured by high performance liquid chromatography (HPLC), flow cytometry, and most recently, high-throughput DNA sequencing (HTS). As understanding phytoplankton communities becomes more imperative due to climate change, evaluating discrepancies and uncertainty in these methodologies becomes vital. Phytoplankton communities in Charleston Harbor are understudied. Charleston Harbor is also experiencing increased urban development and thus represents an interesting system for evaluating methodologies. The objectives of this study are two-fold. The main objective is to examine the phytoplankton community composition, abundance, and diversity in Charleston Harbor. The second objective is to evaluate and examine existing methods for detecting phytoplankton communities. Water samples will be collected in conjunction with those collected by the citizen science group, Charleston WaterKeeper (CWK) from May to October 2023 at four sites in Charleston Harbor. Samples will be evaluated for microscopy, HPLC pigments with CHEMTAX analysis, and metabarcoding DNA analysis using small subunit ribosomal RNA genes. Abiotic parameters will also be obtained to evaluate their relationships with temporal and spatial patterns in PCC. This study is the first comprehensive methodology study of phytoplankton in Charleston Harbor and thus will reveal important insights into this ecosystem.
Feeding and reproductive ecology of three mesophotic octocorals to support restoration in the Northern Gulf of Mexico.
Linde, HS (GPMB, University of Charleston, SC)
In 2010, the explosion of the Deepwater Horizon (DWH) drilling platform triggered an oil spill which released oil and dispersants into the Gulf of Mexico. Both deep-sea and mesophotic benthic habitats were impacted, including several species of mesophotic octocorals. One way to restore these communities is to facilitate the growth of new corals in the laboratory and deploy laboratory-grown corals onto natural reefs. To date, information regarding the nutritional requirements and reproduction of three octocorals impacted by DWH, Swiftia exserta, Muricea pendula, and Thesea nivea, are limited. One way to gain knowledge about octocoral nutrition is through fatty acid analysis. Fatty acids are essential to coral structure, growth, and reproduction. Analyzing fatty acid composition can indicate the origin of fatty acids within tissues, as well as energetic status. This study aims to determine the optimal diet to promote growth and reproductive success in S. exserta, M. pendula, and T. nivea. Results will be achieved by comparing fatty acid composition, health (indicated by polyp behavior and extension), and reproductive traits of octocorals in response to multiple diet treatments. Fatty acid profiles will also be compared in situ, between species and between season, to acquire information regarding feeding and diet. Reproductive success will be analyzed using histology to determine if there is a correlation between reproductive effort and diet. Knowledge gained from this study will support future restoration of Mesophotic and Deep Benthic Communities impacted by DWH, and lead to the restoration of biomass through deployment of healthy corals onto natural reefs.
Prevalence of Toxoplasma gondii in the stranded common bottlenose dolphin (Tursiops truncatus) population and its prey species in Charleston, South Carolina, U.S.A.
McGrew, G (GPMB, University of Charleston, SC)
Climate change directly impacts coastal regions in several ways. Tidal flooding frequency has increased from every 10-24 days a year to every 4-5 days in recent years in the Charleston area. Additionally, since 1958 precipitation during heavy rainfall has increased 27% in the Southeast region. These changes along with other climate change conflicts such as sea-level rise and severe storms have directly contributed to increased runoff in Charleston Harbor. This runoff contains several pathogens that are harmful to the entire marine ecosystem such as Toxoplasma gondii. When oocysts are released via the feces of felids, T. gondii enters the marine environment. T. gondii is a protozoan parasite that infects most species of homothermic animals, including humans. The pathogen is transmitted to definitive hosts through carnivorism or ingestion of sporulated oocysts. Intermediate hosts can be infected through the ingestion of contaminated water or food, intake of uncooked or undercooked meat containing tissue cysts and congenitally from the mother through the placenta. Additionally, oocysts can survive in aquatic ectotherms and maintain infectivity. T. gondii is known to cause mortality in several marine mammal species including the bottlenose dolphin (Tursiops truncatus). A surveillance study from 2003-2007 examining the common bottlenose dolphin in Charleston Harbor found serological evidence of infection by T. gondii in 12 of the 79 dolphins tested. However, few other studies have been conducted on the common bottlenose dolphin with adequate sample size. This project would aim to analyze 100-120 tissue samples ranging from 2010 to the present day. Comparisons between previous studies and this study may be used to relate prevalence of T. gondii over time. This further collection will aid in understanding the implications for the health of the bottlenose dolphin population and its entire ecosystem. Increased detection of antibodies to zoonotic pathogens in marine mammals may be a warning for potential human infection as marine mammals tend to serve as sentinel species. In this study, Polymerase Chain Reaction (PCR) will be used to determine if T. gondii DNA is present in brain and muscle tissues from dolphins collected from 2010-2023. The B1 gene will be targeted and amplified using two primers: forward and reverse based on previous studies. Additionally, brain, muscle, and digestive gland tissues of five common fish species of prey of the common bottlenose dolphin will be analyzed to determine if DNA is present and to potentially link T. gondii infection with prey ingestion.
Effects of Rod and Reel Fishing on the Physiological Stress Response of Southeastern Elasmobranchs and the Post Release Mortality of Atlantic Sharpnose (Rhizoprionodon terraenovae).
Bessette, H (GPMB, University of Charleston, SC)
Catch and release recreational fishing is a common practice in coastal waters like the Charleston Harbor, and is often considered a sustainable method of fishing. However, rod-and-reel fishing can result in physiological stress and mortality for many species. The objectives of this study are to determine the post-release mortality (PRM) of Atlantic sharpnose sharks (Rhizoprionodon terraenovae), and to determine the stress response of Atlantic sharpnose sharks and Bonnetheads (Sphyrna tiburo) to rod-and-reel fishing. To determine post-release mortality, Atlantic sharpnose sharks will be tagged using pop-up satellite archival tags (PSAT), and their movements following release will be monitored. Stress response will be characterized through an analysis of blood samples taken from each shark following capture. This data will be compared to fight time for each shark, as well as environmental parameters and measurements, to determine what relationships exist. A metabolomics approach via Nuclear Magnetic Resonance (NMR) spectroscopy will be used to determine metabolite concentrations found in each blood sample. We predict that Atlantic sharpnose sharks will demonstrate a PRM of approximately 10%, similar to other species in this area. We also predict that both species will see significant changes in metabolite concentrations in response to increased physiological stressors. Determining Atlantic sharpnose shark PRM, in conjunction with the stress data collected, can assist in the effective management of these species. The successful application of NMR spectroscopy to a stress response analysis of elasmobranchs will serve as the first of its kind, allowing for a new avenue of approach when studying elasmobranchs.
Temporal characterization of intertidal macroalgal microbiomes at ‘Ewa Beach, O‘ahu, Hawai‘i.
Dunn, E (GPMB, University of Charleston, SC)
Macroalgae are primary producers and ecosystem engineers that create habitats and food sources for other organisms, and their microbiome is key to their health and morphological development. Macroalgae and their microbiome experience higher light intensity and temperatures at low tide which may alter their microbiome. Changes in the macroalgal bacterial community composition due to abiotic factors, such as excessive temperature and light conditions, can have negative effects on the host organism and impact their success. This study aims to characterize the microbiome of seven species of native and invasive macroalgae during a series of consecutive low-tide events. Algal samples from the phyla Chlorophyta, Rhodophyta, and Ochrophyta were collected from an intertidal bench at ‘Ewa Beach, O‘ahu, HI over five days at low tide in May 2021. Total DNA was extracted and will be amplified via PCR methods using Illumina primers targeting the V3V4 region of the 16S rRNA gene. Cleaned amplicons will be used for community composition analyses addressing variation in alpha- and beta-diversity with observed ASVs, Shannon-Weiner, and Simpson Diversity indices, and non-metric multidimensional scaling ordinations respectively. Temporal changes will be analyzed via redundancy analysis, and PERMANOVA will be used to investigate differences by macroalgal group. Light and temperature data collected in May 2023 during low tide from ‘Ewa Beach were analyzed for trends in intensity along the intertidal bench to characterize variability in abiotic conditions at this site. Understanding microbiome variability in macroalgal communities will determine how these bacteria respond to stress at short time scales, which is important for predicting their response to increasing variability in abiotic conditions from climate change.
Spatiotemporal Prevalence of a Parasitic Dinoflagellate, Hematodinium perezi, in the blue crab, Callinectes sapidus, and the Water Column of the Charleston Harbor Estuary, SC, USA.
Korper, H (GPMB, College of Charleston, SC)
The blue crab (Callinectes sapidus) fishery is one of South Carolina’s oldest and largest fisheries, with landings valued at over $6 million annually. However, since early 2000, commercial blue crab landings have experienced two decades of decline, reaching a 50-year low in 2021. While the decline in blue crab abundance can be associated with a multitude of environmental and ecological changes in the past decades, another focus of concern is the disease dynamic within blue crabs and how it may change over space and time. Blue crabs on the east coast of the United States are susceptible to infection by the parasitic dinoflagellate, Hematodinium perezi, which causes pathological alterations to host organs, tissues, and hemolymph, that can ultimately lead to death. Despite these potential negative impacts, little is known about H. perezi prevalence in the blue crabs and major waterways of South Carolina. The aim of this study is to examine the spatial and temporal prevalence of H. perezi within blue crabs and the water column of the Charleston Harbor Estuary through the genetic detection of the parasite using quantitative polymerase chain reaction (qPCR). The presence of this parasite may covary with environmental conditions, providing foundational information on the dynamics of an influential parasite in the region of South Carolina. This baseline knowledge will be critical for understanding disease dynamics in blue crabs in the Southeast USA and for managing the species.
Ecotoxicological assessment of perfluorooctanesulfonate (PFOS) and temperature on two estuarine fish species, Cyprinodon variegatus and Sciaenops ocellatus.
Thornton, A (GPMB, University of Charleston, SC)
Per- and polyfluoroalkyl substances (PFAS) are widely used in oil and water repellent products and fire-fighting foams. Studies have shown how detrimental PFAS are for the environment and organisms, where they persist and accumulate based on chain length and functional group. One PFAS compound, perfluorooctanesulfonate (PFOS), has been detected in estuarine fish tissues in South Carolina; however, information regarding potential impacts to estuarine fish health and survival is lacking. Rising temperatures due to climate change may alter both organism physiology and the bioavailability of chemical contaminants. This study examines the effects of PFOS on two fishes found in South Carolina estuaries, the red drum (Sciaenops ocellatus) and the sheepshead minnow (Cyprinodon variegatus), under different temperatures. Red drum, a recreationally important fishery in S.C., spend their early life stages in estuaries such as Charleston Harbor, with optimal temperatures between 10oC to 20oC. Sheepshead minnows are a standard toxicity test organism and exhibit a wide thermal tolerance (0-45 oC). They are an ecologically important species, serving as prey for larger fish species including red drum. Acute (96h) toxicity exposures were conducted with juvenile red drum and adult sheepshead minnows to determine the effects of PFOS under optimal and elevated temperatures. Fish survival (LC50 values), respiration rates, endocrine response (cortisol and thyroid hormone levels), and cellular biomarkers (glutathione, lipid peroxidation, and acetylcholinesterase) will be assessed. The results of this study will offer insights into the mechanisms of PFOS toxicity on two estuarine fish. Knowledge of how an important fishery responds to the combination of PFOS and elevated temperature will be essential for creating conservation and management plans.
Behavioral and neurobiological responses to a noxious heat stimulus in the snapping shrimp, Alpheus angulosus: Exploring the potential for pain experience in a decapod crustacean.
Gibbs, JL (GPMB, University of Charleston, SC)
Researchers have an ethical obligation to reduce unnecessary harm to animals that putatively experience pain, and in the United States, policy currently protects only vertebrate animals. A growing body of research suggests that some species of decapod crustaceans are capable of affective pain experience. However, the research in this area has focused on only a handful of species. This study seeks to explore this question in a local species of snapping shrimp (Alpheus angulosus), using behavioral and histological methods. This study’s first aim is to demonstrate conditioned place avoidance in shrimp exposed to a noxious heat stimulus. Injured shrimp will learn to avoid place cues in which they experienced putatively painful stimuli, whereas uninjured, control, and groups treated with lidocaine will not form, or will display significantly reduced, conditioned place avoidance. The second aim is to quantify nitric oxide – a molecule associated with pain processing – in snapping shrimp brains, comparing experimental groups. Heat-injured groups will display a significantly higher density of nitric oxide than uninjured, control, or lidocaine groups, with distribution localized to hemisphere ipsilateral to injury. Support for these hypotheses will represent evidence consistent with the idea of pain in this species. This study will provide a novel characterization of nitric oxide in the snapping shrimp brain and has the potential to provide the first evidence for affective pain experience in a snapping shrimp species, adding to the evidence for sentience in decapod crustaceans. Results from this study have implications for animal welfare policy in research and commercial practice.