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
09:00 AM
To B12 or not to B12: Investigating the effects of vitamin B12 and symbiotic bacteria on the thermal performance of phytoplankton (8825)
Primary Presenter: Brandon Chan, University of Connecticut (brandon.w.chan@uconn.edu)
Phytoplankton are closely linked to symbiotic relationships with their bacteria, impacting each partner’s physiology, the environmental chemistry, and species diversity in the ecosystem. Yet phytoplankton and bacteria interactions are highly impacted by the environment, influencing both the strength and type of interactions. With climate change altering the environmental landscape, it is crucial to understand how changes in temperature will impact symbiotic interactions now and in the future. In this study, we examined how the mutualism between a vitamin B12 producing bacteria in exchange for algal carbohydrates from a phytoplankton is impacted across a temperature range. More specifically, we examined how vitamin B12 (presence/absence) and bacteria (no bacteria, with a vitamin B12 producer, with a non-vitamin B12 producer, and a mixed community) affects the growth rate of the cosmopolitan diatom, Phaeodactylum tricornutum, across its thermal range. Our results suggest that vitamin B12 and vitamin B12 producing bacteria increases phytoplankton growth rate near the thermal optimum compared to no vitamin B12 in the environment. Yet, neither vitamin B12 nor bacteria increase the thermal optimum or maximum of P. tricornutum. These results indicate that mutualistic interactions between phytoplankton and bacteria may not allow phytoplankton to persist when exposed to warmer temperatures, which may negatively impact the aquatic environment and ecosystem in a warming world.
09:15 AM
Impact of Heat Waves Examined Through the Feeding Mechanisms of the Sabellid Worm, Parasabella microphthalmus (8849)
Primary Presenter: Immanuel Burns, Old Dominion University (iburn001@odu.edu)
Climate change and extreme climatic events pose a threat to the biodiversity and productivity of estuarine and coastal ecosystems. Filter-feeding organisms play a critical role in these environments, providing ecosystem functions and services. Heat waves are expected to impact filter-feeding invertebrates by affecting their metabolism, altering their feeding behavior, and impairing feeding mechanisms, such as particle capture and transport. Using the filter-feeding, tube-dwelling feather duster worm Parasabella microphthalmus (Annelida), I propose to study the feeding structures, behavior, and biomechanics of this species under different heat wave scenarios. Marine annelids are an ecologically important, yet under-studied group in climate change biology. They exhibit remarkable diversity and adaptability, as evidenced by their varied feeding strategies, and serve an important role as disturbance indicators in human-impacted habitats. I will use Scanning Electron Microscopy (SEM) to study the morphology of the feeding structures of P. microphthalmus, and Digital Particle Image Velocimetry (DPIV) to explore their filter-feeding mechanisms and behavior. My results will provide a mechanistic understanding of the responses of this species to heat waves and its chances to persist under such conditions, ultimately advancing our knowledge of how anomalous thermal events will affect these coastal filter-feeders.
09:30 AM
Growth & Ingestion Rate of Ochromonas CCMP 1391 Under Nutrient Limitation (8878)
Primary Presenter: Alejandro Mapula, Texas A&M University at Galveston (alexdmapula@gmail.com)
Protistan plankton were historically classified as either strict phototrophs or heterotrophs; we now understand that mixotrophs - organisms that can use multiple trophic modes for nutrient acquisition - are far more prevalent than previously thought. This flexibility between trophic modes may be induced by oligotrophic conditions, but more research is needed to understand the impact of nutrient limitation with the onset of, or increase in, mixotrophic prey ingestion. One mixotroph, Ochromonas sp. (CCMP 1391), is a constitutive mixotroph and a facultative phagotroph. We evaluated the growth and ingestion rates of Ochromonas under nutrient-limited conditions to test the hypothesis that Ochromonas would overcome nutrient limitation by phagotrophically ingesting prokaryotic or eukaryotic prey. To do so, xenic Ochromonas cultures were grown in filtered seawater (FSW)- and artificial seawater (ASW)-based L1 media, under nutrient-replete, reduced nitrogen (-N), and reduced phosphorus (-P) conditions. Nutrient limitation led to diminished Ochromonas growth. The impact of nutrient limitation on the ingestion of algal prey was assessed by growing Ochromonas with the prey species Micromonas and Green fluorescent protein E. coli (in separate trials), while monitoring ingestion rates. While Ochromonas was ingesting the Micromonas and GFP E. coli, we did not find significant differences between nitrogen limitation and the control (control: μ = 8 d-1, -N: μ =5 d-1). Similarly, light limitation did not induce a measurably different ingestion rate relative to the control (light: μ = 2 d-1). Ingestion rates were lower than in previous studies, suggesting that Ochromonas in our experiments could have been feeding on unlabeled prey, and that further investigation is needed to determine a potential impact of prey preference on ingestion rate.
09:45 AM
A PATHWAY TO UNDERSTANDING SOUTHEAST ALASKA’S BIOGEOGRAPHY: COMPARING OCEANOGRAPHIC VARIABLES WITH HUMPBACK WHALE (MEGAPTERA NOVAEANGLIAE) SIGHTINGS IN JUNEAU, AK (8900)
Primary Presenter: Gabrille Lopez, University of Alaska Fairbanks (gabrille.lopez@gmail.com)
Marine conservation depends on understanding ecosystems in their entirety. This is pertinent when predicting an ecosystem’s resilience to climate change as effects from climate change vary among marine habitats. Southeast Alaska (SEAK) has complicated bathymetry and oceanographic processes suggested to be influenced by climate change. Primary productivity is high and areas like Juneau support a diverse assemblage of marine species where humpback whales (Megaptera novaeangliae) migrate annually to feed. Despite SEAK’s vulnerability to climate change and little knowledge of local (i.e. Juneau) processes, no study has yet focused on understanding local oceanographic characteristics and their effects on local biogeography. This study aims to investigate these unknown connections by piloting oceanographic data collection in Juneau, along with whale sightings, to determine environmental drivers of a SEAK marine ecosystem. As whales alter their feeding behavior in relation to prey density, we hypothesize that whales can act as ocean sentinels, serving as determinants to ocean health. The first season of data collection occurred June-Sept. 2024. Oceanographic properties (temperature, salinity, depth, pressure, fluorescence) were collected via a Conductivity Temperature Depth instrument at pre-defined sampling sites in waters near Juneau. Whale data collection consisted of whale location, behavior, and group size. Results will provide insight into regional oceanographic characteristics and how these might indicate broader-scale processes which affect marine ecosystem functioning.
10:00 AM
Phylogenetic and Physiological Characterization of Amino Acid Nitrogen Stable Isotopes in Phytoplankton (8920)
Primary Presenter: Jesus Baca, Texas A&M University - Corpus Christi (bacaje12@gmail.com)
The nitrogen isotope ratios (δ15N) of individual amino acid (AA) have been increasingly used as tracers in contemporary and paleo marine biogeochemistry and trophic ecology. The observed distinctive δ15N signatures among different AAs, in particular phenylalanine (Phe) and glutamic acid (Glu), known as the canonical “source” and “trophic” AAs have been used to retrieve N isotope baseline of food webs and estimate the numbers of trophic transfers in various sample matrices like biota, particles, coral skeletons, and sediments. Although these applications heavily depend on the δ15N -AA produced by phytoplankton, the potential variations of δ15N -AA fabricated by different phylogenetic species remain poorly understood. Here, we aim to help to bridge this gap in knowledge by analyzing the Phe and Glu δ15N values as well as the concentration of AAs within different, well known phytoplankton species, cultured under the same nutrient conditions and in different growth phases and examine its potential effect on trophic position.
10:15 AM
MONITORING DISPERSAL RATES DURING INITIAL OUTPLANTING OF FUNCTIONALLY EXTINCT HATCHERY RAISED HALIOTIS KAMTSCHATKANA (PINTO ABALONE) (8930)
Primary Presenter: Larkin Garden, Catawba College (larkingarden@gmail.com)
Haliotis kamtschatkana, or the pinto abalone, is the only abalone native to and present along Washington’s coast. Its population has severely declined in the last fifty years due to overharvest. Subsequent recruitment failure resulted in it being considered functionally extinct in Washington. Efforts are in progress to restore pinto abalone populations to self-sustaining densities through conservation aquaculture and the outplanting of hatchery-raised juveniles. Alongside other partners, the Washington Department of Fish and Wildlife and Puget Sound Restoration Fund have outplanted thousands of juveniles at dozens of sites across the San Juan Islands since the late 2000s and have refined many of their outplanting methods. However, the effects of outplant tube density on abalone dispersal are unknown. We examined density’s impact on dispersal rate from tubes by outplanting abalone in three densities and recording the number of abalone remaining in each tube for a week afterward. We counted the tubes every hour for the first 16 hours after outplanting which facilitated other interesting observations. We observed predation of what we believe to be healthy abalone by Amphissa columbiana and the possibility of dispersal encouraged by light sensitivity.
SS01A - ASLO Multicultural Program Student Symposium
Description
Time: 9:00 AM
Date: 27/3/2025
Room: W206A