This session is for undergraduate and beginning graduate students, primarily affiliated with the ASLO Multicultural Program (ASLOMP). Students will present their research findings in a friendly atmosphere that encourages constructive criticism. Appropriate submission from students not affiliated with ASLOMP will also be considered. Students may present in this session only once. They are encouraged to present subsequent work in regular sessions.
Lead Organizer: Benjamin Cuker, Hampton University (cukerbenjamin@gmail.com)
Co-organizers:
Jeanette Davis, Hampton University (Jeanette.davis@hamptonu.edu)
Presentations
06:00 PM
IS BLACK SPOT SHELL DISEASE RELATED TO JONAH CRAB HEALTH? (8742)
Primary Presenter: Nyla Thompson, Hampton University (nyla.thompson@my.hamptonu.edu)
Jonah Crab (<i>Cancer borealis</i>) is a growing fishery in New England. Despite previous studies on the related <i>C. pagurus</i>, not much information is known about the Jonah crab nor its shell disease, black spot. Due to concerns about the potential severity of black spot, our study aimed to answer the question: Is black spot disease related to Jonah crab health? Black Spot may negatively affect Jonah Crabs health, which could be observed with impaired health metrics with increased disease. Crabs (n = 71) were collected with the Maine Department of Marine Resources through the Ventless Trap Survey near Vinalhaven, Maine. Hemolymph Brix, hepatopancreas % dry weight, septicemia, and hemocyte total counts were assessed in relation to % black spot cover. These health metrics are indicative of energetic resources (Brix and dry weight) and potential secondary infection (septicemia and hemocytes). Although no significant relationship was found between black spot % cover and the health metrics, a significant relationship between Brix and hepatopancreas % dry weight suggests that Brix could serve as a non-lethal proxy for hepatopancreas % dry weight. Our results suggest black spot has no substantial negative effect on Jonah crab health by our assessed metrics, though this may be influenced by our study on mid-summer crab and does not preclude potential disease impacts concurrent with environmental stressors. This information aids fisheries management and understanding the implications of shell disease in crabs.
06:00 PM
Carbon Substrates and Iron Oxides Influence Methane Production and Iron Reduction in Salt Marsh Sediments (8765)
Primary Presenter: Samantha Reynolds, Millersville University of Pennsylvania (sjreynol@millersville.edu)
Coastal wetlands are major emitters of methane; however, the controlling factors of methane production are not well known, especially in salt marshes. Delaware salt marshes contain abundant iron minerals, which may inhibit or promote methane production, depending on the conditions and the microbial populations present. In anoxic salt marsh sediments, methanogens may be outcompeted by iron reducing bacteria they may engage in a syntrophic relationship with them via interspecies electron transfer (IET). Different organic carbon substrates, which may be seasonally variable in salt marsh sediments, can also promote methane production by through distinct methanogenic pathways. Sediment collected from the Great Marsh in Lewes, Delaware was incubated with four carbon substrates and two iron minerals in this study. Carbon substrates for hydrogenotrophic (H2/CO2), acetoclastic (acetate), and methylotrophic (trimethylamine (TMA), dimethyl sulfide (DMS)) methanogenesis were investigated along with two controls. The iron treatments were either hematite, ferrihydrite, or an iron-free control. The results show an increase in methane production in each of the treatments but the most methane production was found in TMA and H2/CO2 incubations. Methane production in ferrihydrite treatments was delayed compared to hematite, likely due to competition from iron reducing bacteria. The results of this experiment shed light on the potential interactions between iron reducers and methanogens and how the presence of different carbon substrates and iron oxides influence methanogenesis.
06:00 PM
SWIMMING IN STYLE: VISCOSITY DRIVES EUCHAETA NORVEGICA SPEED (8767)
Primary Presenter: Jayla Butler, Johns Hopkins University / Bigelow Laboratory for Ocean Science (jaylab020@gmail.com)
Copepods are among the most abundant metazoans on Earth, dominating many marine zooplankton communities. Copepods range between 0.5 and 10 mm in prosome length, where the larger are found in higher latitudes and colder environments. As temperature decreases across latitudes, water density and viscosity increase. The relationship between these variables and the size and speed of an aquatic organism is best described by the Reynolds number, which measures the ratio between inertial and viscous forces. When copepods use their cephalic appendages to perform cruise swimming, they operate at low Reynolds numbers (1-10). This raises questions about the independent effects of viscosity on swimming behavior: is there an independent effect of viscosity on cruise style swimming? The beat frequency of Euchaeta norvegica performing cruise swimming was measured in waters with differing viscosities. Using polyvinylpyrrolidone (PVP-MW-360kD), a polymer that alters viscosity, we determine that as temperature decreases and viscosity increases, the beat frequency decreases. Our data indicates that changes in viscosity alone significantly affect the beat frequency and can explain 4%-23% of the changes in temperature.
06:00 PM
Tracking Abundance and Diversity of Marine Cyanophages Over Time in Coastal Waters of Puerto Rico (8805)
Primary Presenter: Alondra Urrutia, University of Puerto Rico- Mayaguez (alondra.urrutia@upr.edu)
Marine cyanophages, viruses that infect cyanobacteria, are abundant in seawater and influence ocean biogeochemical cycling and host community structures. While marine cyanophages have been the subject of substantial scientific investigation, very minimal work has focused on their population dynamics within tropical regions like Puerto Rico. To address this gap, we assess and analyze the temporal changes in cyanophages abundance and diversity at two coastal sites in Puerto Rico which are Mayagüez Bay and the La Parguera Natural Reserve. For estimating the abundance and isolating cyanophages, techniques of MPN and ED plates were conducted, respectively, using different types of previously isolated and characterized cell strains (i.e., WH7803, WH8101, WH8018, and CC9311). Data from nine months of sampling reveals that Parguera has more cyanophages infecting WH8101 cells and Mayaguez Bay has more cyanophages infecting WH7803 cells. Even when we have that difference, there are more cyanophages that infect WH7803 than cyanophages that infect WH8101. This study provides the first look into cyanophage population dynamics across two geographic locations around Puerto Rico and already has revealed notable trends.
06:00 PM
Investigating Tidal Effects on Longitudinal Dispersion in a California Estuary Using Satellite Remote Sensing (8816)
Primary Presenter: Dana Myers, University of California, Santa Barbara (drmyers@ucsb.edu)
Elkhorn Slough, a vital tidal estuary located along California's central coast, is an ecologically sensitive area and one of the last coastal wetlands in the state. However, the Slough faces significant environmental challenges, including sedimentation and tidal erosion, due to human interventions and climate change. These stressors threaten its biodiversity and the surrounding wetlands, which are critical habitats for numerous bird species and marine life. While numerical models have long been used to study ocean and estuarine water mixing at fine spatial scales, obtaining observational data at these scales remains challenging due to the limitations of traditional in situ sampling and the coarse resolution of many remote sensing platforms. In contrast, PlanetScope imagery, with its unprecedented spatial (3-meter) resolution and daily revisit times, offers a novel and powerful approach for studying the dynamic mixing of riverine and oceanic waters. This project utilizes observational PlanetScope satellite data to calculate dispersion of water mass mixing and to monitor turbidity throughout different tidal phases. By leveraging this high-frequency imagery, I aim to inform management strategies, assess ecosystem resilience, and predict the impacts of climate change on water quality in the Slough at scales that mirror numerical models. This approach represents a cost-effective, state-of-the-art alternative to traditional in situ monitoring, opening new pathways for long-term environmental monitoring.
06:00 PM
Quantifying surface and bottom seawater chemistry variability on shallow coral reefs in Puerto Rico (8817)
Primary Presenter: Juanita Carballeira Martínez, University of Puerto Rico- Mayagüez Campus (juanita.carballeira@upr.edu)
The ongoing global decline of coral reefs under climate change and other human impacts poses an alarming threat in the ability of coral reefs to provide ecosystem services, directly affecting the livelihood of coastal communities. Ocean acidification is a direct threat to the maintenance of coral reef calcium carbonate structures and has even been projected to shift many coral reefs towards net loss of calcium carbonate annually before the end of the century. The effects of global ocean acidification vary locally, making it essential to understand how local-based factors such as benthic community composition and hydrodynamics interact with global-scale climate change to improve predictions for future changes to coral reef systems. In this study, we quantified spatial, temporal, and vertical differences in seawater chemistry across 42 shallow coral reef sites (5-30 meters) around Puerto Rico throughout 2024. Surface and bottom samples were collected for temperature, salinity, dissolved oxygen (DO), and biological oxygen demand (BOD), as well as the carbonate chemistry parameters total alkalinity (TA) and dissolved inorganic carbon (DIC) that were used to calculate seawater saturation state with respect to aragonite (Ωarg) and pH (total scale). We propose that vertical differences in the physicochemistry of seawater in coral reefs are positively correlated with depth, showing greater variability in areas with a higher percentage of coral coverage. To this end, our ongoing project aims to provide a comprehensive assessment of the physicochemical conditions related to the health and resilience of coral reefs around the island of Puerto Rico.
06:00 PM
DRILL or NO DRILL? How Stramonita haemastoma finds its ideal prey (8821)
Primary Presenter: Jonathan Mai, Gonzaga University (jmai@zagmail.gonzaga.edu)
Eastern oysters (Crassostrea virginica) are an economically and ecologically important species that is plagued by high mortality from predators at early life stages, particularly by the southern oyster drill (Stramonita haemastoma) in the Gulf of Mexico. Oysters can detect predator cues and respond by reallocating energy from growth to increasing shell strength, significantly increasing survivorship. While there is extensive research on how oysters respond to predators, relatively little is known on how drills select the ideal oyster for consumption. We investigated how drills locate oysters and discern prey profitability between oysters reared with predator cues (induced-stronger shells) and without cues (control-weaker shells) through a series of predator choice experiments and behavioral assays. We found that drills would perform a series of inspective behaviors to select prey, first with their siphon and then by physically manipulating the oysters with their foot for an extended period before attempting consumption. Although there was no difference in the number of control and induced oysters drills would choose to handle, drills successfully consumed control oysters twice as frequently as induced oysters. Furthermore, soft tissue mass per shell length did not differ between treatments, indicating that the larger control oysters offered more reward, making them a more profitable prey. Our results match expectations from optimal foraging theory and demonstrate that drills maintain a complex suite of behaviors to select prey. Additionally, these findings indicate that early predator exposure may be a viable strategy to reduce oyster mortality, potentially improving industry yield and restoration efforts.
06:00 PM
The Couch Potato Effect: Comparing the Metabolic Rates of Captive and Wild Clearnose Skates (8824)
Primary Presenter: Kristin Lewis, Howard University (kristin.lewis@bison.howard.edu)
Understanding how captivity plays a role on the metabolism of marine animals is crucial, as it can help to determine future laboratory protocols and provide aquariums and other facilities with knowledge about the effects of long-term captivity. Clearnose skates are the most common elasmobranch species in the Delaware Bay, but little knowledge was known about their metabolic processes. We wanted to understand if there was an effect on the routine metabolic rates of Clearnose skates that have been in captivity. Routine metabolic rate is the metabolic rate for a fasted animal swimming normally. Wild skates were caught in the Delaware Bay, making sure they were of similar size to the group of skates in captivity. In order to determine metabolic rate, the oxygen consumption of an animal needs to be found. For each skate, an intermittent flow respirometer was used to accomplish this by allowing the skate to draw down oxygen for two-hour periods. The system was then flushed which re-oxygenated the water and the process was repeated. Dissolved oxygen of the tank was measured throughout the trial and then used as a proxy to calculate routine metabolic rates of the captive skates were compared to those of the wild, splitting the data analysis by sex. There was not a significant difference found between the metabolic rates of the captive and wild skates, but that could’ve been the result of small sample sizes. Our research may confirm that there was no couch potato effect and Clearnose skate metabolic rates aren’t strongly affected by captivity, but more research needed to be done in order to support that conclusion.
06:00 PM
Ribbed Mussel (Geukensia demissa) Aquaculture Techniques: Investigating an Alternative Diet (8850)
Primary Presenter: Emory Barrett, Rutgers University (emory.barrett@rutgers.edu)
Ribbed mussels (Geukensia demissa) are understudied bivalves that play a critical role in US East Coast marshes. They are in high demand due to their ecological engineering applications, but aquaculture for the species is underdeveloped. Due to their ability to feed upon small particles, we hypothesized that Nannochloropsis oculata (Nanno), a small green microalgae with high lipid content, would be a beneficial supplement to the standard diet of Tisochrysis lutea (Tiso), improving survival and growth. We compared the results of feeding larval and juvenile ribbed mussels a controlled diet of 100% Tiso and an experimental diet of 2:1 Nanno:Tiso. Shell lengths of the two larval diets did not statistically differ at the termination of the diet, but the dataset’s linear regression slopes did. The shell lengths of the two juvenile diets did not statistically differ on the termination of the diets well as in their linear regression slopes. A frequency distribution of all shell lengths on the final day of the study suggested competition among the Nanno-mix mussels for the Tiso portion of the mixed diet. This pattern was not seen in the juvenile frequency distributions. There was no statistical difference in percent survival between the two larval diets. These results show that while larval ribbed mussels prefer Tiso, Nanno can be used as a viable “backup” diet. Ribbed mussel juveniles equally prefer Tiso and Nanno. The difference in preference suggests intraspecific niche partitioning, which outlines areas for further study into ribbed mussel population dynamics.
06:00 PM
BENTHIC STORYTELLING: BIOGEOCHEMICAL RESPONSE TO TRAWLING IN JEFFREYS LEDGE AND STELLWAGEN BANK (8837)
Primary Presenter: Fin Li, Northeastern University (li.sop@northeastern.edu)
Bottom trawling is a widespread commercial fishing practice that holds economic and cultural significance for many coastal communities. However, there are concerns about its ecological impacts, including its effects on the carbon cycle via the resuspension of sediment carbon to the pelagic layer, which could influence carbon emissions. This study investigates the effects of trawling on sediment carbon content and benthic ecosystems at two sites in the Gulf of Maine, Jeffreys Ledge and Stellwagen Bank National Marine Sanctuary. To characterize such effects, we collected and synthesized fisheries and oceanographic data including benthic fauna counts, sediment composition, and trawling intensity. Results indicate trawling is concentrated in areas with high carbon content and robust benthic ecosystems, and that changes in trawling activity lead to shifts in demersal community composition and abundance. To fully evaluate responses to trawling, we highlight a need for more comprehensive temporal data on benthic fauna and sediment carbon measurements, which would address uncertainties in sediment carbon dynamics, improve carbon cycle models, and inform marine conservation strategies related to commercial fishing.
06:00 PM
Sediment grain size distribution and composition of coastal environments at Jobos Bay National Estuarine Research Reserve, Puerto Rico (8859)
Primary Presenter: Xiomara Cruz, University of Puerto Rico (xiomara.cruz8@upr.edu)
Estuaries remove sediments and pollutants from rivers and streams before they enter the ocean, resulting in cleaner water for humans and marine life. However, the health of estuaries has declined as a result of coastal development and climate change. This study focused on Jobos Bay National Estuarine Research Reserve (JBNERR) located in southeast Puerto Rico, conducting analyses of sediment texture and composition of surficial sediment samples from its coastal environments. In December 2023, three independent surficial sediment samples were collected from a total of 16 sites within JBNERR. Grain-size analysis included wet-sieving of 10 g to remove the mud fraction, followed by dry sieving of sand and coarser components. All size fractions were weighed, and grain-size percentages were calculated. Sediment samples were also assessed for calcium carbonate and organic matter content utilizing a Loss on Ignition (LOI) protocol. Overall, mud predominated in most of the sites, however, fine sand was common around the offshore cays, and both coarse and fine sand were found in anthropogenic impacted areas. The LOI analysis revealed higher percentages of calcium carbonate around the offshore cays, higher organic carbon and shell fragments in the mangrove area, and the predominance of siliciclastic in the anthropogenically impacted areas. This analysis of sediment composition and organic matter in Jobos Bay highlights variations among different habitats and sources. These results contribute essential information to support the management and conservation strategies that aim to preserve the diverse ecosystems of JBNERR, while also providing additional data for other studies being conducted in the estuary.
06:00 PM
ASSESSING SAN PEDRO BASIN BOTTOM WATER DYNAMICS: MIT GENERAL CIRCULATION MODEL OUTPUT VERSUS USC SPOT IN-SITU MEASUREMENTS (8864)
Primary Presenter: Katie Chan, University of California Los Angeles (chanks7550@gmail.com)
Dichlorodiphenyltrichloroethane (DDT) is a persistent organic pollutant that poses long-term ecological risks through bioaccumulation in marine organisms. It was extensively dumped along the Southern California coast, including the San Pedro Basin, where DDT has now accumulated in the bottom basin. Understanding the movement of bottom water masses—driven by oceanographic processes like flushing events from sill overflows, and changes in temperature and salinity—is crucial for assessing the distribution and potential re-exposure of DDT. This project evaluates how well the MIT General Circulation Model (MITgcm) reproduces bottom water characteristics by comparing model output with in-situ observations from the University of Southern California San Pedro Ocean Time-series (SPOT) collected between 2016 and 2017. We focus on the model’s representation of temperature and salinity profiles, and emphasize the deepest sill at 740 meters in driving bottom water exchanges. Initially, the MITgcm indicated warmer, saltier bottom water and increasing temperatures with depth, contrasting with SPOT observations. After May 2017, model predictions improved, aligning more closely with the observed inverse relationship between temperature and salinity at 800 meters depth. Despite these improvements, the model exhibits a freshwater bias, especially in the last three months of each year, and shows evidence of excessive vertical diffusion. Accurately modeling these dynamics is vital for understanding how DDT disperses in the San Pedro Basin and assessing risks of pollutant exposure in the ocean.
06:00 PM
HOT DRAMA? USING IN SITU IMAGES AND ENVIRONMENTAL DATA TO UNDERSTAND INTERACTIONS BETWEEN LARVAL FISHES, THEIR PREDATORS, AND PREY. (8862)
Primary Presenter: Abby Kong, Amherst College (abbyckong@gmail.com)
Most fishes start their lives as planktonic larvae, and understanding this life stage is critical, as larvae can experience up to 99% mortality. While in the plankton, larval fishes must find adequate food, avoid predators, and grow in order to exit this perilous environment. Larval fish prey availability and predation stress are likely to change with environmental conditions, especially with rising ocean temperatures and changing climates. We used in situ imagery of larval fishes and their planktonic prey and predators to measure predator-prey distances to better understand how these fine-scale interactions may change with the environment. A plankton imager (In situ Ichthyoplankton Imaging System, ISIIS) was deployed on cross-shelf transects near Newport, Oregon in the summers of 2018 and 2019, and a sCNN classified all plankton images. A random sample of 125 image frames containing a larval fish was analyzed by identifying all organisms and measuring the distance from each larval fish to each planktonic organism in the frame. In 2018, temperatures were generally higher while chlorophyll-a and salinity were lower. Concurrently, larval fishes were larger, there were 44% more prey in the same frame, fewer predators, and larval fishes occurred at shallower depths than in 2019. There were no significant differences in larval fish distances to predators or prey between the years. These fine-scale data suggest that the distance between predators and prey is not as useful of a metric as the total number and distribution of larval fishes relative to their prey and predators. Warmer temperatures and abundant prey in 2018 is consistent with the overall larger fish sizes in 2018. Changing temperatures in the future are likely to influence the predator-prey interactions of fish during their larval stage through modulation of prey availability and predator presence.
06:00 PM
ANALYSIS OF MICROBIAL COMMUNITIES OF MACROCYSTIS PYRIFERA GAMETOPHYTES: CHARACTERIZATION OF METAGENOME-ASSEMBLED GENOMES AND ISOLATED BACTERIA (9660)
Primary Presenter: Pascal Cabuzel, University of Southern California (cabuzel@usc.edu)
Macrocystis pyrifera (giant kelp) is a brown macroalga that is found in coastal coldwater marine environments and is known for its accelerated growth. It plays a significant role ecologically (as a keystone species) and economically (as an aquaculture product). Seaweed-associated bacteria play a crucial role in the functional biology of their host. Despite the significance of microbial and kelp interactions, the microbiota of kelp remains understudied. We analyzed the 5 most abundant genera present in a set of 178 gametophytes (haploid life stage) sampled from 4 different sampling sites Channel Islands (Cl), Leo Carrillo (LC), Camp Padleton (CP), Arroyo Quemando (AQ). We compared bacterial MAGs through pangenomes and phylogenetic analysis to determine the dynamic between bacterial phylogeny and the host genotype in consideration of their respective geographical location. Alongside comparative genomics, we created a collection of bacterial isolates that are representative of their host and sample location. We determined if cultured bacteria were similar to those identified in the MAGs. This work expands our basic understanding of these ecological interactions and could support the argument for the presence of a core microbial community during the gametophyte life stage and perhaps suggest kelp selectively of specific bacteria, as well as enabling further scientific investigation. Analysis of the core genes and flexible genes illustrated differences in genes in correlation to the sample sites. These gene differences included contrasts in vitamin B biosynthesis.
06:00 PM
Machine learning identifies fish communities from environmental DNA (eDNA) (8907)
Primary Presenter: Henry Sun, Duke University (hs325@duke.edu)
Biodiversity measurements of fish species are often conducted phenotypically, using extractive methods such as bottom trawls to physically capture and record organisms. In New Jersey waters, proposed offshore wind developments are amplifying the need for such measurements to to evaluate wind farm effects on fisheries. Environmental DNA (eDNA) metabarcoding offers a cost-effective, non-extractive method to survey fish biodiversity and abundance whilst minimizing environmental impacts. However, the complexity of high-dimensional eDNA data often hinders effective data analysis and clustering. We demonstrate that nonlinear dimensionality reduction techniques can outperform linear methods like PCA at visualizing high-level eDNA data in two dimensions. Following initial analysis and visualization of eDNA data, we utilized random forest machine learning (ML) models to predict fish species presence and community composition from oceanographic data. ML models were constructed for winter mixed, summer stratified, and combined seasonal data, using temperature and salinity as predictors. We found models were most accurate at making predictions in summer, correctly predicting species presence 80.6% and community cluster assignment 66.7% of the time. ML models also identified a significant contribution of oceanographic features towards fish community distributions in the Mid-Atlantic Bight. Future research can validate eDNA-derived community clusters against extractive trawl survey data to better inform fish stock assessments and regional offshore wind development.
06:00 PM
MICROPLASTICS IN MARINE SEDIMENTS: EFFECTS ON MICROBIAL STRUCTURE AND FUNCTION REVEALED BY A FLOW-THROUGH REACTOR EXPERIMENT. (8925)
Primary Presenter: Alexis Ruiz Agosto, University of Puerto Rico Humacao (alexis.ruiz9@upr.edu)
Microplastics are prevalent in aquatic environments, their accumulation and integration in marine sediments is imminent. The presence of microplastics complicates our understanding of how pollutants affect microbial dynamics, structure, and function in different environments, and their impacts for ocean biogeochemical cycles. This study investigated microbial interactions with polyethylene (PE) microplastics in estuarine sediments using a flow-through reactor experiment over 14 days. As part of an REU project at the University of New Hampshire, we conducted an experiment to investigate microbial communities found in sediments and their capacity to break down organic matter and compare it to those attached to microplastics. The microplastics were incubated in natural seawater prior to the start of the experiment, representing biofouled microplastics reaching the ocean floor. Sediment flow-through reactor experiments consisted of a constant input of seawater into sediments, where sampling was conducted at three time points (2, 7 and 14 days). The sampling procedure looked at the bacterial cell abundance, microbial community structure (16S rRNA sequencing), biofilm concentration, and potential hydrolytic activity of seven enzymes of sediments and microplastics added to the treatments. Further analysis of our results could lead to the understanding of -who’s there and what are they doing-, related to the microbial interactions with microplastics. Ultimately, our study gives insight into which could be the consequences of microplastics once they reach the ocean floor.
06:00 PM
EXAMINING THE RESPONSE OF WIDESPREAD SEDIMENT ASSOCIATED CABLE BACTERIA ACTIVITY TO A LABORATORY MANIPULATION (8931)
Primary Presenter: Liz Collazo, University of Puerto Rico at Humacao (lizcoll04@gmail.com)
Cable bacteria are long filamentous sediment-associated microbes, found in marine and freshwater environments, capable of electron transport along their filaments from sulfide to oxygen. Their activity is often responsible for a majority of the oxygen consumption and sulfide depletion in sediments. Cable bacteria have an important role in biogeochemical cycles and have the potential to abate toxicity of pollutants in the environment. Cable bacteria serve as electron acceptors where oxygen is not available, potentially stimulating the activity of other beneficial microbes in the sediment environment. To test how cable bacteria interact with other bacteria in sediments, we need a means to interrupt their activity. A previous experiment suggested there may be enhanced activity of cable bacteria following an experimental cutting treatment. Over time, cable bacteria are able to re-orient their position to 'plug' back into oxygen. The objective of this study was to test if the activity of cable bacteria is stimulated by cutting their access from oxygen. My approach was to conduct a time series incubation experiment. In a container, I mixed the upper 20 cm of the sediment cores collected from the main channel in the Chesapeake Bay with artificial sea water; this was then sealed to asphyxiate and subsequently remove macrofauna. Then, I incubated the sediment in core liners with pre-cut slits and hose clamps, pushed up by a few millimeters with a silicone stopper, under oxygenated conditions in aquaria, to stimulate the growth of cable bacteria. Once cable bacteria were growing, in a subset of experimental sediment cores, I performed a 'cutting treatment' by passing a fishing line horizontally through the sediments. I then continued to follow the activity of cable bacteria over time in the intact sediments and in the 'cut treatment' sediments. The activity of cable bacteria was tracked using microsensor profiling. My hypothesis was that the cutting treatment would enhance the activity of cable bacteria, by driving the filaments to reconnect with oxygen. Here, using pH and electric potential microsensors, I assessed the activity of cable bacteria before and after manipulating the sediment to directly observe if cable bacteria activity may be stimulated by a cutting treatment. In this contribution I will discuss how various manipulations impacted the activity of cable bacteria.
06:00 PM
BIODIVERSITY OF HIGH SALINITY SALTERNS IN SOUTHWEST PUERTO RICO (8957)
Primary Presenter: Bianca Rojas, University of Puerto Rico (biancarojasrivera1@gmail.com)
A variety of organisms live within the hypersaline environments of both the active and derelict salterns in southwest Puerto Rico. The stable, tropical conditions in these habitats favor the establishment of steady microbial communities. The unique biocenoses found in salterns are comprised of halophilic organisms including fungi, bacteria, archaea, and algae, each playing a crucial role in nutrient cycling and organic matter decomposition. Little is known about the microbial composition of these extreme biotopes. The fungal assemblage, in particular, is not well characterized. Understanding the biodiversity of Puerto Rican salterns will provide many benefits. High biodiversity can indicate a stable, healthy ecosystem and resilience to changes or stressors. Many organisms in high-salinity environments have developed unique biochemical pathways to survive the harsh conditions. Enzymes from these organisms can be valuable in biotechnology and industry, with potential applications in medicine, biofuels, and agriculture. Saltern ecosystems are sensitive to environmental disruptions, making their population dynamics valuable indicators of broader ecological shifts due to climate change. Changes in microbial diversity, for example, can signal alterations in temperature, salinity, and other environmental factors. We will use molecular phylogenetic approaches to understand the process in the kingdom Fungi. Time series water samples from representative salterns in the Puerto Rican Southwest will be collected and the 18S rRNA will be sequenced and matched to public databases. The water samples will also be used to inoculate media of varying salinities to determine culturability and compare the diversity of lab cultures to environmental samples.
06:00 PM
SPATIAL PATTERNS IN THE CORAL ECOSYSTEMS OF PAPAHĀNAUMOKUĀKEA MARINE NATIONAL MONUMENT (8972)
Primary Presenter: Khrista Nicholas, University of Miami (khristanicholas1@gmail.com)
The Papahānaumokuākea Marine National Monument (PMNM) is a cultural and ecological hub in the Northwestern Hawaiian Islands. Largely undisturbed by local human urbanization, it holds high biodiversity and endemism isolated in the Pacific Ocean. To monitor PMNM’s reef system, research expeditions have collected benthic and fish underwater SCUBA survey data since 2000. Our project used these data to conduct an updated biogeographic analysis of PMNM. This helps characterize the marine resources of PMNM and identify areas where further research and conservation efforts are needed. Our goal is important to the preservation of PMNM in the face of anthropogenic climate change, marine debris, invasive species, and other human impacts. We used the R coding platform to organize data, identify patterns, and create ecological visualizations that represent the benthic and fish populations across the monument. Our results show that PMNM is an interconnected web of coral reef ecosystems, with each island having a unique profile of fish populations, benthic cover, and oceanographic setting. This suggests that each island in PMNM supports a unique marine ecosystem and may have a different standard of what health looks like. More data are needed as we continue to identify patterns through time at multiple atolls. This will help us recognize hotspots of ecological importance and monitor their condition. This is key to improving conservation efforts of PMNM ecosystems that provide resources for vulnerable marine life and local Hawaiian communities in the face of rapidly changing environments.
06:00 PM
SEASONAL MICROPLASTIC ABUNDANCE AND COMPOSITION IN RIVER BIOTA LINKED WITH LAND USE AND SPECIES TRAITS (9008)
Primary Presenter: Alexandra Brown, California State University Bakersfield (abrown84@csub.edu)
Microplastics (MPs; < 5 mm) are a pervasive contaminant in freshwater habitats and biota. Terrestrial-aquatic exchanges move plastic litter into aquatic habitats where they may fragment into MPs and enter the food web. We sought to understand the importance of watershed land use and landcover (LULC) and river tributaries in connection to the sources, abundances, and compositions of MPs entering a freshwater lake. We investigated 1) if seasonal MP abundance in freshwater biota vary with species traits across a LULC gradient, and 2) the potential relationships between MP patterns in biota and their habitats. Eight river tributaries differing in dominant LULC were sampled seasonally for MPs in surface water, benthic sediments, fish, and macroinvertebrates. Preliminary results from 3 of the rivers indicated MP contamination was present in river habitat, fish, and macroinvertebrate samples, with fibers contributing approx. 97-100% of all MP particles. Surface water samples contained an average of 16 particles/sample. Eighty-five percent of fish individuals across functional feeding groups (e.g., detritivore) contained an average of approx. 13 MPs/fish. There was a positive relationship between MP concentrations and fish trophic fraction, suggesting that MPs may move through the food web due to species trophic traits (X2= 14.18, P= 0.001). This study is anticipated to further reveal potential links of MP pollution to environmental variables (e.g., season). This will inform targeted MP mitigation strategies and increase our knowledge of the ecological consequences of MP pollution.
06:00 PM
SENTINELS OF CHANGE: WARMING SIGNALS IN MOUNTAIN LAKE COMMUNITIES OVER THE PAST 25 YEARS (9017)
Primary Presenter: Meili Soriano, University of California, Irvine (sorianomeili0723@gmail.com)
As global temperatures rise, community assemblages in terrestrial, marine, and aquatic ecosystems are shifting, with warmer-adapted species becoming more prevalent while cooler-adapted species decline, a process known as thermophilization. Community thermal indices (CTIs) quantify the thermal affinities of entire communities and are key to forecasting future biodiversity patterns, allowing us to attribute species turnover to climate change and predict the influence of warming on ecosystem function. Our study aims to investigate the impact of environmental change on the thermophilization of zooplankton communities in montane lakes. Utilizing zooplankton diversity and environmental data from the Sierra Lakes Inventory Project (1995-2002) and the Eastern Sierra Nevada Mountain Lakes Long Term Monitoring Program (2013-present), we have determined the thermal affinities of zooplankton species, which range from 15°C for a large-bodied keystone grazer Daphnia melanica to 21°C for a small-bodied cladoceran, Scapholeberis mucronata. We then quantified the CTIs of zooplankton assemblages in Eastern Sierra Nevada lakes. We analyzed long-term shifts in zooplankton CTIs by comparing communities from 1995 to 2024 and assessed short-term differences by examining how CTIs varied with snowpack - an important determinant of water temperature in mountain lakes. Our project demonstrates how zooplankton in montane lakes are responsive to long- and short-term variations in temperature in an era of long-term warming and increased variation in snowpack.
06:00 PM
Identifying mollusk species in the freshwater bodies of New Mexico (9654)
Primary Presenter: Nyrobi Whitfield, Oberlin College (whitfield.nyrobi@gmail.com)
Due to its proximity to the Chihuahuan Desert, New Mexico has an arid environment with sparse water bodies that are remote and undocumented but can also be biodiverse oases. As a result, little research has been done on its native freshwater organisms, leading to the inquiry of what mollusk species reside there. To answer this question, I collected organisms from an ephemeral spring called Ojo del Abo on the southeastern edge of the Manzano Mountains and a pond that was cut off from the Rio Grande River. Preliminary observation of the collected organisms revealed that the vast majority were sinistral snails, a rare trait that allowed for me to recognize them to be a part of the Physidae family. Physidae freshwater snails are known for their unique ability of phenotypic plasticity, which enables them to change their shell morphology in response to biotic and abiotic factors in their immediate environment. This enhances their ability to adapt and causes generations and even individuals to look different from each other. As a result, shell morphology alone could not be used to identify the species, and penial morphology and behavior were used complementary. Identified species from Ojo del Abo included the freshwater snail species of Lymnaea cockerelli, Lymnaea cubensis/viator, and Physa gyrina as well as the freshwater clam species of Sphaerium striatinum. The Rio Grande pond was less diverse and less abundant with only the species of Lymnaea cubensis/viator and Physa gyrina being collected. Phenotypic plasticity was most evident in the Physa gyrina whose varying shell colors and aperture sizes allowed for inferences on the environmental conditions faced by these organisms. These results led to the implication that because climate change and global warming will have significant impacts on the environments of these organisms, it will also impact their morphologies.
06:00 PM
THE ROLE OF TEMPORAL ISOLATION ON REPRODUCTIVE ISOLATION IN FUNDULUS GRANIDS AND F. HETEROCLITUS (9651)
Primary Presenter: Taj Nash, Hampton University (taj.nash@my.hamptonu.edu)
Reproductive barriers are anything that exists in nature and can reduce gene flow between species. It can be physical, such as a geographical constraint, or it can be due to genetic differences that prohibit species from producing viable offspring. These can be either a prezygotic or postzygotic barrier. By studying the impacts of reproductive isolation on gene flow, scientists can grasp a better understanding of how species evole. The objective of the present stuy is to determine the seasonal reproductive cyclyes of two species of killifish in an area of overlap to determine its effect on reproductive isolation. For a year, monthly samples of thirty individuals will be sampled from Bing's Landing, which is one place in which these species overlap with very rare hybridization. With caudal fin clippings, genetic analysis will be performed to genotype species and identify specific alleles. A histological analysis will also be conducted using the Gonadosomatic Index along with Gamete Volume Fractions to estimate species reproductive timing. Each species' reproductive timing will be used to clarify the strength of temporal isolation on reproductive isolation. This study can provide a complete picture on speciation, which is a central concept of biological sciences.
06:00 PM
SEM ESTABLISHES A CONNECTION FOR THE FUSED SETULES OF BARNACLE LARVAL SWIMMING APPENDAGES (9643)
Primary Presenter: Roberto Ponce, California State University of Long Beach (poncer.8575@gmail.com)
Due to small size and slow swimming, most zooplankton exist in a world dominated by viscous forces, Re<1, where movement results from reciprocating appendages with high and low drag postures. Crustacean zooplankton have plumose appendages consisting of setae with setules that form open fans (high drag) and semi-closed or collapsed setal arrays (low drag) during the power stroke-recovery cycle. The thoracic swimming appendages of barnacle cyprids (last larval instar) are unusual in that the setules of adjacent setae are joined at their tips to create a linkage that is an ordered mesh. How these setules are connected was explored with scanning electron microscopy (SEM). Neither light microscopy nor SEM show interlocking or hooked structures at the setule tips. SEM images show the linkages consist of two setules with slightly curved tips that adhere to one another. With SEM we found a similar linkage pattern among the appendages of four balanamorph species. Attempts to chemically disrupt these linkages were unsuccessful. Setal arrays were spread with a coverslip to break the connections and allowed to close to simulate the relaxed position of the appendages. Upon being reopened, the setular linkages were found to have re-formed. What causes the natural adhesion between setule tips is still unknown. Further exploration of adhesion and surface properties of the setules is needed. The result of this study enhances our understanding of the functional anatomy of the swimming appendages of cirriped cyprids and could apply to a similar phenomenon found in copepods, a related taxon.
06:00 PM
Evaluating Salivary Cortisol as a Non-Invasive Alternative to Blood in Beluga Whales (Delphinapterus leucas) (9619)
Primary Presenter: Emily Charles, University of Alaska Anchorage (ercharles@alaska.edu)
Beluga whales (Delphinapterus leucas) reside in Arctic waters, which are ground-zero for climate change. While it is difficult to study wild beluga health, animals under professional human care provide opportunity to gather important data on beluga physiology. The gold standard for monitoring health is blood; however, non-invasive sample matrices offer alternative approaches for rapid, easy, and repeated sampling. This study aimed to determine if beluga salivary cortisol is a relevant alternative to blood by 1) comparing cortisol in saliva vs. blood and 2) determining if construction-related drilling sounds result in a detectable increase in salivary cortisol. Paired saliva and blood samples were collected from three trained whales at Mystic Aquarium over 1 year. Saliva was also collected during exposure to drilling noise. Salivary cortisol was measured using a Cayman Chemical Cortisol ELISA Kit. A single animal showed a significant correlation between blood and saliva cortisol (R=0.721; p=0.019), yet no significant relationship was detected in the total data. The monthly average salivary cortisol was 78.15 +/- 51.20 pg/mL. During noise exposure, two whales had increased cortisol (265.52 and 173.96 pg/mL). While saliva shows promise for monitoring cortisol, more work is needed to determine the blood and saliva relationship and investigate individual variation in physiology. This work contributes to the development of saliva as a non-invasive sample for monitoring health which can be applied experimentally within aquaria to help us understand beluga physiology.
06:00 PM
Response of stream filamentous algae and benthic periphyton to wildfire ash (9591)
Primary Presenter: Carly Steckling, Arizona State University (steckcar21@gmail.com)
Wildfires are novel aridland disturbances due to human activity, invasive grasses, and excessive wet seasons. Sycamore Creek, an intermittent stream in central Arizona, has recently experienced two large fires. Ash is transported during rain storms and influences stream ecosystems by decreasing dissolved oxygen and increasing dissolved organic carbon, organic nitrogen, and inorganic nitrogen. In streams, algae in filaments and periphyton are responsible for most primary production and play an important role in nitrogen and carbon cycling. The nitrogen input from ash is expected to enrich algal biomass growth with increased concentrations of ash exposure. Ash was collected in the mid-reaches of Sycamore Creek, then analyzed for carbon and nitrogen composition. A leachate was created by shaking one part ash with three, five, or ten parts Nanopure water for one hour and letting it sit for 48 hours before removing particles with a 0.45 μm syringe filter. Due to a lack of water in Sycamore Creek, filamentous algae are collected from aridland Rye Creek. Periphyton in Rye Creek is scraped from benthic rock sediment and homogenized in a slurry with Nanopure. 40 glass mesocosms are filled with 200 mL of Nanopure water, 1:3 leachate (10), 1:5 leachate (10), or 1:10 leachate (10). Five mesocosms of each group have 10 grams dry weight of filamentous algae and five mesocosms have 20 mL of periphyton slurry. The mesocosms are placed for one week in a photoperiod and temperature controlled room. Algal biomass is measured as chlorophyll α and ash-free dry mass.
06:00 PM
Sub-Tidal Water Levels on the Coast of Florida from Tide Gauges (9582)
Primary Presenter: Ian Kahn, University of New Mexico (waterjonbeats@gmail.com)
Florida is at a particularly high risk of flooding due to sea level rise. There is a need to understand this risk across the state. Initial studies have indicated a difference between this risk on the east coast and west coast of Florida. The 1975 - 2022 NOAA tide gauge records along the US southeast coast were used to better understand the processes of water level variation in the region. To eliminate the dominant tidal signals, the monthly averages were computed for each station. Long term mean monthly climatology were computed from the monthly averages. The residual water levels were therefore dominated by climate signals. Correlations between the monthly residuals were computed. The east coast stations generally showed high correlations between them. Similarly for the west coast stations, but the correlation between east coast and west coast stations was relatively low. Resilience planning for Florida communities should consider this difference between east coast and west coast sea level variations.
06:00 PM
CONFIRMING SEAL PRESENCE BY ANALYZING ENVIRONMENTAL DNA (eDNA) & RNA (eRNA) (9564)
Primary Presenter: Gavin Pirtle, UC Davis (Gavinatwork1@Gmail.com)
Identification of the aquatic mammal species in environments has been challenging due to constraints with traditional surveys. Moreover, human impact on marine mammals is still unknown. With offshore wind farm development throughout the East Coast, there are potential impacts on marine mammals. Environmental DNA (eDNA) and RNA (eRNA) have successfully been utilized to investigate species’ presence. This research focused on the development and application of eDNA /eRNA detection on gray seals (Halichoerus grypus). The research questions were: 1) Can we identify gray seal DNA/RNA within aquatic environments? 2) How long do the DNA/RNA signals persist within aquatic environments? Water samples were collected from the Animal Rescue Clinic of Mystic Aquarium when the seals were present (Pre) after the seals were removed for release (Post) and during the release back to the ocean (Field). Following filtering, DNA and RNA were extracted simultaneously, and real-time PCR (qPCR) quantification of a mitochondrial control region was performed. The results showed the mean RNA yield (4796ng) and DNA yield (1094ng). qPCR results on eDNA suggest that gray seal species can be observed for up to 11 days and up to 1 day using eRNA following removal. Moreover, the seal eDNA concentrations showed a linear decrease over time (R2 = 0.9595). Preliminary results suggest the possibility of detecting gray seal presence in aquatic environments by examining water. Further validation can potentially be utilized to help determine changes in the distribution of endangered marine mammals due to stressors.
06:00 PM
Predicting Climate Extremes with Synoptic Climatology in the Chesapeake Bay (9543)
Primary Presenter: Tyrell Cooper, The College of Wooster (ty.cooper4242@gmail.com)
Synoptic climatology describes the relationship between the climate system and certain surface conditions. Many studies in the field have focused on understanding changes to long-term and broad climatic processes. This project aims to provide results that will benefit near-shore communities by focusing on better understanding climate extremes. Correlations made between climate modes and climate extremes are observed to be stronger than relationships between climate modes and average weather patterns (St. Laurent et al., 20022). For that reason, we correlated the climate modes North Atlantic Oscillation and Pacific Decadal Oscillation to 16 climate extreme indices (Pirhalla et al. 2024). We collated 39 years of historical sea level pressure (SLP) to weather data being temperature and precipitation for the region. We utilized the principal component analysis (PCA) to reduce high dimensionality among the SLP. We implemented the self-organizing map (SOM) algorithm to create sets of grids representing spatially consistent and temporally distinct pressure patterns. We then visualized the probability of climate extreme occurrence during the SOM’s seasonal distribution using star plots. Select star plots were chosen for correlation due to their high probability and seasonal occurrence. Scatter plots with linear best fit lines and shaded relief for degree of confidence were generated to represent these correlations. The final plots provide us with estimations for the likelihood of extreme events occurring during the respective phase of climate mode.
06:00 PM
LONG-TERM VIABILITY OF MICRORNAS IN MARINE MAMMAL ARCHIVED SAMPLES (9530)
Primary Presenter: Halia Morris, Hampton University (halia.morris@my.hamptonu.edu)
MicroRNAs (miRNAs) are conserved short non-coding RNAs that regulate gene expression in nearly all eukaryotes. These epigenetic markers have been extensively used in disease and organ injury diagnosis in humans but their use in wildlife studies has been limited; little is known about their resilience in samples collected under non-sterile conditions post-mortem. Here, we assessed long-term miRNA viability in marine mammal skin tissues using two approaches: (1) conducting time-series experiments with freshly dead stranded dolphins using various preservatives for over a two-year period and (2) comparing miRNA extracts from samples obtained from live animal biopsies and post-mortem/ stranded skin tissues, in samples archived in formalin, ETOH and salt- saturated DMSO archived for 2-6 years. These approaches revealed that, with the exception of formalin, high quality miRNA extracts can be consistently obtained from dolphin skin biopsies or stranded specimen irrespective of preservative and length of preservation. We observed that freeze-thaw cycles ( greater than 3 cycles) can significantly negatively impact sample viability so we recommend sub-sampling prior to preservation whenever possible. Our study confirms previous reports using human sampling studies that miRNAs are remarkably resilient to degradation, particularly in comparison to messenger RNAs (mRNA). The increased resilience of miRNAs, largely due to their coupling with Argonaute proteins, make them promising markers for wildlife studies.
06:00 PM
Variable levels of genetic population structure across the circumpolar distribution of Weddell seals (9529)
Primary Presenter: Ian Santos Rodriguez, Hampton University (ian.rodriguez1@my.hamptonu.edu)
The rapid warming observed in the Northern Antarctic Peninsula (NAP) has led to a reduction in winter sea ice and significant changes in the ecology of krill-dependent pinniped species have been observed in the past decade. Weddell seals (Leptonychotes weddellii) are extensively studied in Antarctica; however, there is a notable absence of information regarding the NAP region. Broad scale genetic analyses suggest that genetic and geographical distance are correlated and there is significant population differentiation across the species range. Consequently, we hypothesize that Weddell seal populations in the NAP are genetically connected to other northern populations, such as South Georgia. To investigate this hypothesis, we will obtain mtDNA sequencing data from Weddell seal tissue samples (n= 28) collected by the NOAA Antarctic Marine Living Resources program (US AMLR). We will analyze this dataset in the context of publicly available data (n= 395) from other populations across the species circumpolar distribution. The findings of this study will provide valuable insights into the ecology and conservation status of NAP Weddell seals, thereby contributing to the overarching goal of understanding the effects of changing environmental parameters on vulnerable polar mammal species.
06:00 PM
A DIVE INTO THE COLOR MORPHOLOGY OF FIJIAN PORITES CYLINDRICA (9484)
Primary Presenter: Colin Tang, University of Delaware (colin3.14tang@gmail.com)
Shallow-water, reef-building corals are crucial to the ecosystems they inhabit. Their symbiosis with dinoflagellate algae (Symbiodiniaceae) allows them to inhabit and enrich oligotrophic waters, acting as primary producers and structure for other animals. Corals are heavily threatened by climate change, and active restoration has become an increasingly common means of conservation within these ecosystems. In our study, we sought to connect coral thermal tolerances with non-invasive phenometric measurements. We collected and sampled corals from the coral coast in Fiji with a custom-built fluorometer and a coral bleaching automated stress system (CBASS). One of the species in our study set was Porites cylindrica, a fast-growing and relatively heat-tolerant coral which has two color morphologies: brown and yellow. We compared the heat tolerance and phenometric data between the two color morphs. Small, albeit significant, reductions in the absorbance values and in the maximum quantum yield of PSII (Fv/Fm) were observed in response to thermal stress within both color morphs. However, no significant differences in response to thermal stress were observed between color morphs, nor were differences in phenometric data found. Many coral species have multiple color morphs and understanding if thermal stress differs across these color morphs could be important towards improving restoration efforts.
06:00 PM
Mercury Concentrations in Marine Micronekton with Habitat Depth and Distance from Shore in Southern California (9456)
Primary Presenter: Alyssa Raynor, University of South Carolina (raynoralyssa2@gmail.com)
Mercury (Hg) is a neurotoxicant that bioaccumulates to harmful concentrations in high-trophic level animals. Micronekton (mid-trophic organisms between 2-20 cm) are important prey for high-trophic organisms. Hg and drivers affecting Hg bioavailability to micronekton are understudied despite the roles of these mid-trophic taxa in directly exposing high-trophic levels to Hg. For a 9-week research project, we examined how total mercury concentration ([THg]) in micronekton from Southern California varies between crustaceans and fishes, muscle tissue and whole body, habitat depth, and shore station (a proxy for surface productivity). In October 2023, specimens were collected using a 10m2 Multiple Opening/Closing Net and Environmental Sensing System. In the lab, specimens were dissected into muscle tissue and carcass to estimate whole body [THg], and analyzed for [THg] with a Nippon MA-3000 Direct Mercury Analyzer. [THg] did not differ between crustaceans and fishes. Whole body and muscle [THg] varied but were highly correlated within each species, so muscle [THg] can be used to estimate whole body [THg]. [THg] in crustaceans increased with habitat depth but did not increase in fishes, which may be explained by differences in ages or diets of fishes analyzed. [THg] in specimens collected at the offshore station were higher than at the nearshore station for all species examined, but differences between stations were not significant. This research expands our understanding of how Hg in micronekton varies with environmental conditions, affecting Hg exposure to high-trophic levels.
06:00 PM
Discovering Natural Product HDAC Inhibitors from Marine Microbial Crude Extracts (9446)
Primary Presenter: Julia Sutton, Howard University (julia.sutton@bison.howard.edu)
This research, conducted at the Scripps Institution of Oceanography over the summer, focused on exploring marine microbial communities as a source of novel cancer therapeutics. The ocean’s vast biodiversity, particularly its microbial populations, represents an underexplored reservoir of bioactive compounds with significant potential for biomedical research. Employing microbiological culturing techniques alongside advanced analytical chemistry methods, such as compound isolation and structure elucidation, I identified natural products from marine microbes and evaluated their inhibitory effects on cancer cell proliferation through cell-based assays. The results revealed several bioactive compounds, some of which demonstrated significant cancer-inhibiting properties in initial tests, showcasing the promising role of marine microorganisms in drug development. These findings provide new insights into how the ocean can contribute groundbreaking solutions for human health, particularly in cancer treatment. Moreover, the identification of these bioactive compounds highlights the critical role marine ecosystems play in advancing biomedical discoveries. This research underscores the importance of ocean conservation, as preserving marine biodiversity not only sustains the environment but also ensures continued access to invaluable resources for future therapeutic discoveries.
06:00 PM
Analyzing the Seasonality of Rhizaria at BATS (9343)
Primary Presenter: Serena Aguilar, Arizona State University (sgaguil1@asu.edu)
Rhizaria are a super diverse group of skeleton-bearing marine protists that are ubiquitous in the world’s oceans. Foraminifera and Radiolarians are two predominant lineages of Rhizaria found in the Sargasso Sea. Despite their importance to biogeochemical cycling and sinking particles in the ocean there are still limited studies of the seasonality of Rhizaria, especially from those areas where they are more abundant, the mid-ocean subtropical oligotrophic gyres, an environment representing 40% of the Earth's surface. Using zooSCAN image data from samples taken at the Bermuda Atlantic Time Study (BATS) site from March 2016 to May 2017, we found that Rhizaria size remains constant throughout the sampled period, while transparency shows significant change seasonally. The transparency of the images Rhizaria exhibits a bimodal distribution which distinguishes the denser, more opaque Foraminifera from the more transparent Radiolaria. The morphometric analyses allowed us to discriminate between these two groups, indicating a difference in the seasonality patterns for both groups, linked to the hydrographic conditions in the region.
06:00 PM
Using information about population structure to optimize the spatial scale of groundfish stock assessments along the US West Coast (9193)
Primary Presenter: Holland Vernon, Weber State University (hvernon1226@gmail.com)
Sustainable fisheries management relies on understanding the population structure of harvested species in relation to their management units. When spatial variation in genetics, movement, and/or life history traits are unaccounted for, we risk localized depletion or under-utilization of the resource. As such, defining the spatial stock structure of all federally managed species is legally mandated and a high priority for the Pacific Fisheries Management Council (PFMC). Many groundfish species are assessed as a single stock along the US West Coast. When sufficient data are available, finer-scale stock assessments are used to model subpopulations that are often delineated by state boundaries and/or biogeographic breaks. We conducted a comprehensive literature review to qualify evidence of spatial population structure for all species listed in the Pacific Coast Groundfish Fishery Management Plan. First, we synthesized species-specific information related to 1) genetic variation, 2) larval dispersal, 3) adult movement, and 4) other life history traits. We then compared the best scientific information available (BSIA) with the spatial scale of recent stock assessments. Where discrepancies were found, we recommend modifications to the spatial extent of stock assessment models. Better alignment between biological and management processes are likely to improve estimates of stock status and associated management decisions, which can have considerable impacts on coastal communities.
06:00 PM
Exploring Vessel Noise off the Coast of Santa Barbara with Long-Term Passive Acoustic Monitoring (9171)
Primary Presenter: Yovanni Fabian Bernardino, San Diego Miramar College (yovannifabian8@gmail.com)
This study explores vessel noise off the coast of Santa Barbara, adjacent to the Channel Islands National Marine Sanctuary, using long-term passive acoustic monitoring to investigate potential strategies for reducing anthropogenic acoustic presence. Acoustic data from the Channel Islands National Marine Sanctuary, collected between 2015 and 2023 by Scripps Institution of Oceanography UC San Diego, was synchronized with Automatic Identification System (AIS) data to identify the sources of specific noises. Further analysis with Maersk and CMA CGM vessels revealed positive linear relationships between speed and sound intensity, and vessel length and sound intensity. These findings suggest that reducing vessel speed and length could help minimize acoustic impacts.
06:00 PM
EXPLORING THE ROLE OF MARINE RNA VIRUSES IN PHYTOPLANKTON BLOOM DYNAMICS - A MESOCOSM STUDY (9095)
Primary Presenter: Makena Gichuru, University of San Francisco (mkgichuru@dons.usfca.edu)
Marine RNA viruses are abundant and diverse in the global ocean. Their ability to infect a wide range of protistan and invertebrate hosts makes them ecologically relevant, as many confirmed hosts are important primary producers and drivers of carbon export (e.g., diatoms, dinoflagellates, and raphidophytes). Despite their importance, RNA viruses remain understudied with metrics such as biomass, biogeographic distribution, abundance patterns, and ecological significance in marine ecosystems poorly constrained. Our project aims to bridge this gap by observing the relationship between RNA viruses and putative hosts in a controlled experiment. In this study, we stimulated a (mostly diatom) bloom in seawater-filled mesocosms with daily sampling of the microbial and viral communities. DNA and RNA from the mesocosm samples will be extracted and sequenced, bioinformatic analyses will determine the composition of viral, bacterial, and protistan communities, and statistical analysis will be used to infer relationships. The data collected in this study will help us better understand the role that marine RNA viruses play in the progression and potential termination of phytoplankton bloom events. Given that RNA viral hosts are important contributors to oceanic carbon flux, conclusions drawn from this research will have potential applications in global ocean carbon modeling.
06:00 PM
EVALUATING FACTORS INFLUENCING MALE ALLIANCE FORMATION IN TAMANEND’S BOTTLENOSE DOLPHINS (TURSIOPS EREBENNUS) (9056)
Primary Presenter: Angelic Nunez, Bowdoin College (anunez@bowdoin.edu)
Bottlenose dolphins (Tursiops spp.) live in fission-fusion societies, meaning the composition of groups change over relatively short time periods (i.e., hours or days). However, in some populations, long-term bonds are formed between males; the reason why these male alliances form is not well understood. One leading hypothesis for male alliance formation is high dolphin population density. Preliminary analyses indicated Tamanend's bottlenose dolphins (Tursiops erebennus) in estuarine waters near Savannah, Georgia have formed male alliances. Thus, we determined population density and distribution of allied males to evaluate hypotheses of male alliance formation. The population density of dolphins of Savannah, Georgia was 0.899 d/km2, which is under the threshold of 1.0 d/km2 hypothesized by Ermak et al. (2017) to lead to male alliance formation. Sightings of allied (n=4) and non-allied (n=4) male dolphins were mapped to visualize their sighting locations. Allied males were found in less complex habitats with open water, while non-allied males were found in complex habitats with smaller creek widths (p < 0.05). Previous studies have suggested that habitat complexity may deter formation of male alliances, but the waters near Savannah, Georgia have a highly complex habitat and still have male alliances, indicating additional mechanisms leading to alliance formation. It is possible that no single factor influences male alliance formation; rather, locations with or without allied males have multiple factors influencing formation of these bonds.
06:00 PM
IN THEIR SYMBIONT ERA: IDENTIFYING MICROBIAL COMMUNITIES IN MAUI SHALLOW-WATER CORALS IMPACTED BY WASTEWATER (9055)
Primary Presenter: Grace Mathis, University of Mary Hardin-Baylor (graceyvonne2004@yahoo.com)
Nutrient pollution and ocean acidification harm shallow-water coral health by disrupting coral host and symbiont interactions. Zooxanthellae, endosymbiotic algae in coral tissues, provide essential nutrient products from photosynthesis but may be expelled during host stress, increasing the risk of coral bleaching and disease. Corals also rely on a stable prokaryotic population for nutrient cycling and pathogen resistance. In the Kahekili Herbivore Fisheries Management Area (KHFMA) of Maui, Hawaii, scleractinian corals are exposed to high nutrient concentrations and decreased seawater pH from sewage treatment plant wastewater entering the reef through submarine groundwater vents. This study compares microbial communities in KHFMA corals at varying proximity to a vent site. Coral tissue, mucus, and reef water samples collected underwent DNA extraction. We amplified 16S rRNA using V4-V5 primers 515F-Y/926R to characterize prokaryotic associations and enhance our understanding of their roles in coral health and resilience in reef ecosystems impacted by nutrient pollution. We also optimized the PCR protocol with SYM_VAR_5.8S2/SYM_VAR_REV primers, which have increased specificity for the Internal Transcribed Spacer 2 (ITS2) region of Symbiodinium. By assessing Symbiodinium clade diversity at sites near and far from the vent, we aim to uncover unique zooxanthellae responses to stressors and coral recruitment of zooxanthellae in nutrient-polluted areas. This study may aid in developing improved methods to promote coral success for future conservation and restoration efforts.
06:00 PM
EVALUATING THE EFFICACY OF DRY STORAGE OF SHRIMP GILL TISSUE ON FTA CARDS FOR PCR-BASED MONITORING OF THE CILATE RESPONSIBLE FOR SHRIMP BLACK GILL DISEASE (9052)
Primary Presenter: Grace Aduasare, Binghamton University (gaduasa1@binghamton.edu)
Shrimp black gill (sBG) disease is an emerging epidemic in the US Southeastern shrimp fishery (Gulf of Mexico and subtropical western North Atlantic). The causative agent of sBG disease is a newly described parasitic apostome ciliate, Hyalophysa lynni. Previously, to investigate and monitor sBG disease, a diagnostic PCR-based assay was developed. In this study, in an effort to streamline the disease monitoring process, the use of Flinders Technology Associates (FTA) cards was evaluated for storing shrimp gill tissues dry for downstream PCR and other DNA based assessment. Utilizing a model system consisting of grass shrimp (Palamonetes spp) infected by a closely related but non-pathogenic apostome ciliate H. chattoni, the efficacy of storage of gill tissues dried on FTA cards was evaluated. Efficacy was evaluated by determining PCR detection of ciliate DNA from fresh tissue and tissues stored in either a 70% ethanol solution or dried on FTA cards. There was no significant difference in detection of infection prevalence (p = 0.618) associated with these storage methods. These results suggest that FTA cards are suitable for storing dry shrimp gill tissue for disease diagnostic testing by PCR.
06:00 PM
High light tolerance comparisons between five strains of coccolithophore Emiliania huxleyi (9040)
Primary Presenter: Mackenzie Frey, University of Delaware (mfrey@udel.edu)
Emiliania huxleyi is a species of coccolithophore, an abundant and diverse group of phytoplankton. E. huxleyi are able to thrive in most of the world’s oceans despite environmental variability. The ability to bloom across wide environmental gradients indicates either broad tolerance to variable conditions or high intraspecific genetic diversity. In previous studies, high light exposure has negatively affected photosynthetic efficiency (Fv/Fm) in E. huxleyi. Our study expands on past research by comparing Fv/Fm across five strains of E. huxleyi isolated from different environments. Strains were exposed to varying levels of natural sunlight, then allowed to recover in low light intensities. Both the Fv/Fm decrease in response to high light exposure and its subsequent recovery varied with strain. This indicates that intraspecific variability in E. huxleyi light tolerance plays a role in promoting the cosmopolitan distribution of the species. This gives rise to further research questions involving what causes light tolerance in phytoplankton, and how this may reveal why E. huxleyi is able to tolerate the variable conditions of the ocean.
06:00 PM
DETERMINING WHETHER IRON IS A LIMITING IN THE GULF OF MAINE (9036)
Primary Presenter: Kayla Ellerbe, University of Miami (kaylaellerbe@gmail.com)
Trace metals, including iron, play a role in the distribution and productivity of phytoplankton. Iron is found in relatively low concentrations in saltwater systems, due to its low solubility. Previous studies have quantified Fe availability and found it may be a limiting nutrient in the summer in the North Atlantic, but no recent measurements within the Gulf of Maine have been made with trace metal clean sampling. Over two cruises in June and July 2024, we measured dissolved and particulate iron and macronutrients (nitrate+nitrite, phosphate, and silicate) at 15 m at 3 stations along a horizontal transect, and depth profiles at 2 of the stations. Seawater was filtered through a 0.4 um cartridge filter (Acropak) at sea and then acidified with trace metal grade HCl for analysis of dissolved iron. Whole seawater was filtered through a 0.4 um polycarbonate filter and halved for total and labile particulate iron analysis. Inductively coupled plasma mass spectroscopy (ICP-MS) was used to quantify iron and phosphorus concentrations. Macronutrients were measured using standard autoanalyzer methods. Dissolved and particulate iron was lower offshore away from river input and higher toward the benthic layer. Particulate labile Fe/P in reference to phytoplankton stoichiometry of cells showed a large abiotic source of labile Fe that increased with depth. Refractory Fe/Al conclude that iron is enriched over aluminum in comparison to the average crustal values. The dissolved N/Fe values were below 10 mol/mmol, suggesting nitrogen limitation before an iron limitation for surface values.
SS01P - ASLO Multicultural Program Student Symposium
Description
Time: 6:00 PM
Date: 29/3/2025
Room: Exhibit Hall A