2026 Abstracts

Poster 1

From Seaweed to Seedlings: Characterizing Sargassum-Derived Biostimulants for Sustainable Agriculture
Emma Ackleson William and Mary MBL, Mayra Sánchez-García, M.S. MBL, Loretta Roberson, Ph.D. MBL

Funding
Schmidt Sciences and the Foundation for Food and Agriculture Research

Abstract
Holopelagic Sargassum is a type of brown macroalgae native to the Atlantic Ocean that has increasingly formed major blooms and coastal accumulations. This is negatively affecting marine biodiversity and coastal ecosystems and decreasing overall environmental health. Converting Sargassum biomass into bioproducts may provide a sustainable strategy for managing these accumulations. One potential application is the production of agricultural biostimulants to reduce reliance on synthetic fertilizers that contribute to environmental degradation. This study characterized Sargassum biostimulants and evaluated their effect on Arabidopsis thaliana plants. Three extraction methods were investigated: autoclave extraction, alkaline hydrolysis, and pressate extraction. These were then compared with a commercial biostimulant derived from the brown algae Ascophyllum nodosum. Each treatment was analyzed for carbohydrate content, antioxidant capacity, reducing sugars, total phenolic content, protein concentration, and Mannitol concentration. The biological activity of the extracts was evaluated using A. thaliana seedlings grown in well plates on agar-based media supplemented with each biostimulant treatment. Seedlings were imaged weekly and assessed for root length, lateral root number, root branching density, leaf area, chlorosis, and survival. Preliminary results indicate that the autoclave extraction biostimulant produced the highest specific growth rate (% day-1), lowest chlorosis scores, and highest survival rate among the various treatments, therefore supporting its potential as an affective biostimulant. Variation among different treatment groups suggests that extraction methods influence both the chemical composition and biological activity of Sargassum-derived biostimulants. These findings demonstrate the potential of converting Sargassum biomass into agricultural biostimulants to support both coastal biomass management and the development of more sustainable crop-production systems, reducing the dependence on synthetic fertilizers.

Poster 2

Skating Away: The Predatory Response of the Juvenile Little Skate
Jocelyn Acosta (Middlebury College), Stacy Farina (Howard University), Allen Mensinger (University of Minnesota Duluth)

Funding
NSF- REU Site Biological Discovery in Woods Hole
DBI- 2349548

Abstract
Sensory systems are often studied under ideal conditions for sensory function. However, the physical environments of organisms present many situations in which sensory function could be obscured or diminished. For example, elasmobranchs, especially batoids (skates and rays), may experience reduced sensitivity of the lateral line when they are buried in the sand, hindering predator detection. In general, little is known about the role of the lateral line and electroreceptive systems in predator avoidance. While the ventral lateral line and electroreceptive organs have been hypothesized to be obscured when skates and rays are resting on the substrate, it is unclear whether the dorsal lateral line system could also be affected by sand deposition during a predator detection event. To test this, we quantified the ventilation rate of juvenile Little Skate (Leucoraja erinacea) individuals before and after a 10-second predator stimulus. We simulated tail movements of a common predator (Atlantic Cod) using a silicone tail made from a custom 3D-printed mold connected to a servo motor to replicate a tailbeat frequency of 5 Hz. Twenty individuals were acclimated to a tank with sand for at least one hour before the stimulus, and most individuals buried themselves during acclimation. A negative correlation was found between percent coverage and the difference between mean ventilation rate before and after the predator stimulus. Further research on the response differences between females and males as well as the importance of burying as a predator avoidance response should be explored.

Poster 3

Investigating the Evolution of Indirect Neurogenesis in Crustaceans
Priyanshu Arora (Patel Lab) UChicago

Funding
Metcalf

Abstract
The human cortex is a highly evolved brain structure that regulates diverse higher-order behaviors. Outer radial glia generate the neurons of the cortex by dividing asymmetrically to self-renew and generate transit-amplifying intermediate neural progenitors. Similar to outer radial glia, Drosophila Type II neural stem cells generate intermediate neural progenitors that produce neurons of the central complex, a conserved higher-order brain structure that regulates complex behaviors such as navigation and sleep. During evolution, these specialized neural stem cells appear to generate more complex and diverse neurons. Whether this type of neural stem cell exists in a primitive crustacean is unknown. Drosophila Type II neural stem cells express the transcription factors Pointed and Earmuff, known markers differentiating them from the other neural stem cells. Using antibody staining and HCR in situ hybridization, we screened for Deadpan across Parhyale embryonic stages to test whether its expression localizes to candidate neural stem cells. In future studies, we will perform single-cell RNA sequencing of the Parhyale brain, which will help us identify more molecular markers and neuron types of the embryonic and adult Parhyale. These studies are the first attempt to investigate indirect neurogenesis in crustaceans, and the findings will provide insights into the evolution of indirect neurogenesis.

Poster 4

Funding
University of Chicago Jeff Metcalf Internship Program
NIH/NINDS 1U19NS12038-01

Abstract
Adenosine Deaminase Acting on RNA (ADAR) is an enzyme present in all animals. It hydrolyzes Adenosine into Inosine, a base that ribosomes read as Guanosine, often leading to re-coding events. Site-directed RNA Editing (SDRE) is a therapeutic tool that uses ADAR’s re-coding capacity to change protein function. In SDRE, the catalytic domain of ADAR is fused to an RNA binding domain that recognizes particular structures within a guide RNA, which guides ADAR to the target A. In our system, a bacteriophage protein, λN, redirects ADAR's activity by recognizing RNA hairpins present in guide RNAs.

Because of λN’s viral origin, it may trigger an immune response when introduced as a therapeutic. This project tests an alternate system that uses ADAR’s Z nucleic acid binding domain Zα as opposed to λN. Zα recognizes Z-nucleic acids, which are left-handed helices characterized by a zigzag backbone. Zα from humans and from squid were tested, as cephalopods naturally edit re-coding regions at high levels and the difference between human and squid Zα is a focus of the lab. Z-DNA was added to guide RNAs for Zα to guide ADAR to the target A.

An mRNA edit in a sodium channel predicted to suppress pain signals was used to test the new system. The guide RNA and the Zα-Deaminase Domain were transfected into HEK cells that express the channel. RNA was then extracted and editing efficiencies were determined.

Preliminary results show that the Zα systems can drive editing, indicating that Zα recognizes the Z-DNA in guide RNAs. Interestingly, squid Zα drove higher editing than the human Zα and the established λN system. This indicates a difference in affinity between human and squid Zα. Furthermore, the Zα systems appear to be more precise than the λN. Thus, Zα offers a non-viral alternative to our current SDRE model.

Poster 5

Funding
Funding: National Science Foundation under Grant No.2517807

Abstract
Dynamic cell shape remodeling and migration require coordinated interactions between the cell membrane and the actin cytoskeleton, mediated by integrins and other cell adhesion molecules. The neural cell adhesion molecule NCAM/CD56, an Ig superfamily adhesion molecule highly expressed on human natural killer (NK) cells, plays a key role in regulating integrin-mediated adhesion turnover, actin cytoskeletal remodeling, and directed cell migration.   NCAM-knockout (KO) NK cells show impaired migration on two-dimensional surfaces coated with integrin ligands. This impaired migration is accompanied by an increased density of high-affinity LFA-1 integrin clusters and dysregulated actin remodeling. These data suggest that NCAM is required for proper NK cell adhesion and migration. To further investigate the role of NCAM in a three-dimensional context, we implemented a larval zebrafish xenograft model. In order to analyze the effect of NCAM deletion on 3D migration dynamics in a complex microenvironment, we imaged lymphocytes expressing fluorescently labeled LifeAct-mScarlet that were injected into vasculature of Tg(fli1:EGFP) zebrafish larvae. Our data suggest that loss of NCAM does not impair NK cell extravasation within the zebrafish vasculature. These findings show that even though NCAM is important for integrin-mediated migration on two dimensional substrates, its role in migration and extravasation  within a complex three dimensional in vivo environment differs. Current studies will further quantify migratory behavior, cell localization, and trafficking dynamics to better define the role of NCAM in NK cell migration in vivo.

POSTER 6

Funding
DBI- 2349548 NSF- REU Site Biological Discovery in Woods Hole;
2311106 LTREB Renewal: Nutrients and climate as drivers of carbon sequestration and ecosystem metabolism in a nitrogen-enriched, shallow coastal ecosystem

Abstract
Eutrophication can alter community composition of an ecosystem when nutrient levels and sources change. West Falmouth Harbor, a eutrophied estuary in Cape Cod, Massachusetts, has seen a 25% decrease in N loading two decades after the Town of Falmouth Wastewater Treatment Facility upgraded its treatment plan. We aimed to use marine macrophytes as indicators of eutrophication by quantifying their abundance and N composition to determine N source and supply. Benthic samples were taken at four subsites in three sections of the estuary in summer 2026. Seagrass and macroalgae were sorted and biomass quantified. Tissue was analyzed for %N and δ15N. Our results showed seagrass was the most abundant benthic primary producer in Outer Harbor and Middle Harbor, with the highest biomass found in Middle Harbor. Macroalgal biomass was relatively similar in these sites. By contrast, biomass of seagrass and macroalgae in Snug Harbor was lower overall. Relative macroalgae biomass varied with Chlorophyta and Phaeophyta dominant in Outer Harbor and Rhodophyta and Phaeophyta dominant in Middle Harbor and Snug Harbor. Current levels of tissue %N of primary producers in Middle Harbor and Snug Harbor were 1% higher than in Outer Harbor, indicating a higher supply of N at those sites. δ15N values were heavier in Outer Harbor at 7.2 ‰, lighter in Middle Harbor at -2.9 ‰, and in between in Snug Harbor at 1.5 ‰, indicating at least 2 different N sources. Current δ15N values differed from historical data, with the most notable change being a large decrease in Middle Harbor, suggesting a shift in N source from wastewater to atmospheric or regenerated N. Our results give a current snapshot of benthic community abundance and N source and supply in West Falmouth Harbor which can be compared to historical data to detect changes in ecosystem health and recovery.

POSTER 7

Funding
Florida Atlantic University: School of Environmental, Coastal, and Ocean Sustainability (WLW-ECOS)

Abstract
Decades of high Nitrogen loading from septic systems has altered the ecological and biochemical processes in most Cape Cods estuaries, resulting in extensive recovery efforts from state and local government. The leading restoration strategy is watershed sewering with Little Pond being among the first to undergo this method. To examine this system, we divided the watershed boundary into three catchment areas upper, east, and west. A mass-balance table was developed by combining meteorological, water quality, and local municipality datasets from the past decade to model annual flux. Total nitrogen input was considered from atmospheric deposition, streamflow, and tidal exchange, as well as septic flow prior to complete sewer installation. The results of this analysis indicated that total nitrogen loading and net loss to Vineyard Sound both significantly decreased from 2016 to 2025. This suggests that the reduction in nitrogen exported was not totally proportional to the reduction in inputs. From these results we can infer that Little Pond is recovering at a substantial rate, but net nitrogen retention has not changed significantly post sewering. These results indicate that the estuary is now becoming more efficient at internal nitrogen processes before exporting to Vineyard Sound.  It is plausible that this is due to an increase in denitrification and sediment burial; however, further research would need to be conducted to corroborate this hypothesis.  The results of this study were beneficial in quantifying estuarine response to a significant reduction in nitrogen loading, and this model can be applied to other affected estuaries to evaluate system response time.

POSTER 8

Funding
Non-traditional model organisms fellowship program

Abstract
Parrotfishes are coral reef-dwelling members of the Labridae family, which primarily propel themselves using their pectoral fins. Within Labridae, a gradient of swimming strategies exist: some fish row through the water with drag-based forces, some fish fly through the water, taking advantage of lift-based forces, and others utilize intermediate strategies. Parrotfish reside on the lift-based end of this spectrum. Resultingly, the pectoral fins of parrotfish are specialized for aquatic flight and contain branching patterns and stiffness gradients which differ from the fins of their rowing wrasse relatives. Parrotfish are an ideal model for the study of aquatic flight and trends in locomotor evolution but are difficult to study due to size limitations as well as a lack of breeding and functional genetics. Biomimetic robotic models, however, can circumnavigate these limitations and provide insight into the design of underwater submersibles as well as tackle evolutionary questions surrounding the radiation and diversity of coral reef fishes. We constructed a robotic actuator that was able to replicate the fin stroke of a parrotfish using kinematic data. When combined with model pectoral fins, the robot was able to generate decinewton thrust forces in water.

POSTER 9

Funding
This work was supported by the University of Chicago Jeff Metcalf Summer Undergraduate Research Fellowship

Abstract
When many vertebrates, such as humans, experience severe tissue damage, their bodies will heal by generating scar tissue. While this method effectively supports the integrity of the tissue, it leads to a loss of function. However, there are some vertebrates that can heal without generating scar tissue and that can maintain functionality, such as the axolotl (Ambystoma mexicanum). The axolotl has immense regenerative capabilities, able to reform limbs, regrow a spinal cord with full function, and much more. By studying the underlying molecular mechanisms of their regenerative abilities, we can investigate how we might be able to create treatments to maintain function and scar-free healing after acute trauma. One such mechanism is the use of neuropeptides as neurotransmitters to signal the regrowth and reformation of lost tissues. Previously, specific neuropeptides were found to be upregulated in the brain after a distal injury, indicating that they play a role in the regenerative process. Here, we are investigating the role of Galanin, a neuropeptide that was found to be upregulated in the hypothalamus one day post injury after spinal cord. I will present preliminary data on the effects of inhibiting this neuropeptide on tail and limb regeneration.

POSTER 10

Funding
This research was supported by the Dartmouth College E.E. Just Program for STEM Advancement, the Owens Family Foundation, and the Vetelsen Foundation.

Abstract
Bacteria adapt to environmental and biological pressures through genomic variation. Diversity-generating retroelements (DGRs) can promote more protein variation than any other genetic mechanism found in nature by introducing targeted mutations into specific genes. However, it remains unknown whether exposure to environmental virus-like particles affects DGR-mediated diversification in cyanobacteria. To investigate this question, we developed a method for challenging the cyanobacterium Nostoc punctiforme with virus-like particles collected from a freshwater stream near Eel Pond in Woods Hole, Massachusetts. Bacterial cultures of N. punctiforme were inoculated with concentrated virus-like particles from environmental soil and water samples and maintained untreated cultures as controls. DNA was collected before inoculation, 48h post-inoculation, and 96h post-inoculation, and DGR variable regions were targeted with amplicon sequencing. The pending sequencing analysis will compare DGR-target sequence variation between exposed and control cultures over time. In parallel, comparative-genomics analysis revealed that closely related DGRs are found in other model isolates of the genus Nostoc. Together, these approaches examine both the short-term response and broader evolutionary distribution of cyanobacterial DGRs. This work establishes a framework for testing whether DGR-mediated diversification contributes to cyanobacterial responses to biotic stress.

POSTER 11

Funding

Abstract
Mines generate large volumes of acidic wastewater enriched in dissolved metals that upon discharge contaminate surface water and groundwater, disrupting aquatic communities, and threatening human health through bioaccumulation. Conventional treatment of such effluent is costly, motivating interest in macroalgal biomass as a low-cost biosorbent. This study evaluates the remediation potential of three macroalgae representing the major algal lineages: Sargassum spp. (Phaeophyceae), Ulva expansa (Chlorophyta), and Gracilaria mammillaris (Rhodophyta). Initially, we tested the absorption capacity of live and dried biomass by exposing the biomass to 1 ppm Cu, and a 1 ppm metal mix exposure containing As, Fe, Cu, Co, Ni. In addtion, G. mammillaris and U. expansa were exposed to mine-influenced water (pH 5.0; 20 ppt) sourced from an Arizona copper mine site. Samples were exposed to the treatment for 72 hr at a density of 24 g L-1 , 70-100 mol m -2 s -1, 12:12 hr light:dark cycle. We determine the Specific growth rate (SGR) for live biomass to determine survivability and all biomass was air dry for major and minor elemental composition and carbohydrate analysis. SGR varied among species, G. mammillaris sustained positive growth across every treatment, including the mixed metals and influenced mining water. Sargassum grew consistently under both metal treatments. In contrast, U. expansa declined considerably under Cu and metal mix exposures, yet tolerated  influenced mine water. These responses identify live Sargassum and G. mammillaris as the more potential candidate for mine influenced water; forthcoming tissue metal concentrations will quantify their biosorption capacities.

POSTER 12

Funding
DBI- 2349548   NSF- REU Site Biological Discovery in Woods Hole

Abstract
Cephalopods are venomous predators that use toxins produced in the posterior salivary gland (PSG) to immobilize prey and facilitate feeding. In many cephalopod species, males and females differ in morphology, ecology, and reproductive investment, and growing evidence suggests that venom composition may also vary with sex and reproductive maturity. To investigate these patterns in Doryteuthis pealeii, we are using an integrated comparative approach to characterize venom composition across maturity stages (juveniles and adults) and sexes (females and males). As part of this study, posterior salivary glands and reproductive tissues were dissected, and sex was confirmed using a quantitative PCR (qPCR) assay that measures gene dosage of a Z-linked marker. This assay distinguishes homogametic males (ZZ) from hemizygous females (Z0), providing accurate sex assignment for downstream venom analyses.

POSTER 13

Funding
DBI- 2349548 NSF- REU Site Biological Discovery in Woods Hole

Abstract
As anthropogenically-sourced CO2 in the atmosphere increases, oceanic temperatures are expected to rise, and pH is expected to drop. As pH and temperature conditions reach abnormal levels, corals expel the symbionts that provide them with food. Ocean acidification also decreases aragonite saturation in seawater, making it difficult for corals to build skeletons. A 4-week controlled experiment was conducted to observe the impact of decreased pH and increased heat on Astrangia poculata. Treatments with decreased pH, increased heat, or both simulated projected ambient conditions in 2050. Treatments also included a coculture with Sargassum filipendula to test if the seaweed mediated the effects of added CO2 on the corals, as photosynthesis removes CO2 from the water. Calcification rate was calculated by measuring buoyant weight at the beginning and end of the experiment, then using an equation from the literature. Symbiont density was measured by counting symbionts in a given area pre- and post- experiment. Maximum photosynthetic yield was measured weekly using a Walz Germany P2500. Corals in treatment with low pH, high heat, and S. filipendula had significantly fewer symbionts post-experiment. Calcification rate did not significantly vary between treatments. In ambient conditions, A. poculata in coculture with S. filipendula showed a trend of higher photosynthetic yield than A. poculata without S. filipendula. However, in high heat and pH treatments, S. filipendula presence did not prevent decreases in photosynthetic yield. From these results, we cannot conclude that S. filipendula mitigates the effects of environmental stress on A. poculata. However, as A. poculata can survive with a lower symbiont density and in freezing temperatures, continuing to study A. poculata and its interactions with other species provides valuable insight into the effects of climate change on corals, and informs tropical coral conservation.

POSTER 14

Funding
University of Chicago Non-Tradition Model Organisms Fellowship

Abstract
Despite many advances in genetics research over the past decades, the use of CRISPR in non-model organisms remains limited. This raises the question: why are there so few CRISPR transformation protocols in non-model organisms? CRISPR is widely used in crop development and plant science, but its application is largely restricted to Arabidopsis and a handful of other well-established species. It remains difficult to functionally characterize genes in non-model systems - which limits the applications of research outside of a lab environment. We aim to establish CRISPR-mediated gene editing in Boechera stricta to facilitate functional characterization of genes in this ecological model system.

Our goal was to develop a protocol for CRISPR-mediated transformation in Boechera stricta. We focused on the gene PDS3, a common proof-of-concept target in gene editing because it is conserved across most plant species and produces a discernible phenotype (albinism) when knocked out. We staggered plant growth to test several CRISPR-introduction methods: floral dip, explant transformation, and protoplast transformation. Using Primer-BLAST, we designed gRNAs to target PDS3 in Boechera and developed primers to sequence across the targeted region. Through PCR and Sanger sequencing, we confirmed that these primers successfully amplify the targeted region in untransformed plants.

We will use Golden Gate assembly in combination with Agrobacterium-mediated delivery for CRISPR transformation, and are currently refining plasmid transformation into competent E. coli cells. Ultimately, we hope to establish a reliable protocol for CRISPR-mediated transformation in Boechera, expanding the toolkit available to plant geneticists and encouraging broader research into non-model organisms.

POSTER 15

Funding
Florida Atlantic University, School of Environmental, Coastal, and Ocean Sustainability

Abstract
Seagrass is a key organism in coastal communities and climate resilience, contributing to habitat space, food sources, and carbon storage. Currently seagrass is disappearing due to climate change, pollution, coastal development, and other anthropogenic phenomena. This work is a subproject of a larger scale restoration effort, as it aims to assess the impacts of different cultivation methods on seagrass growth and health metrics. Genetically identical plants of eelgrass (Zostera marina) were planted in two sediment types: a natural mixture of sand and mud collected locally, and artificial sand spiked with fertilizer. To evaluate impacts between sediment types, we measured the following health indicators:  growth rates, photosynthetic performance, and carbon and nitrogen storage. Growth rates were slightly higher in natural sediment compared to artificial sediment. Carbon and nitrogen pools indicate the natural sediment supplied more nutrients than artificial, supporting the observed trend in growth and indicating that future studies should potentially use higher fertilizer concentrations with artificial sediments. However, both cultivation methods show an adjustment period equally in photosynthetic rates and lower stress indicators. These results suggest that artificial sediment may be a viable, scalable alternative for larger seagrass restoration efforts, and can be applied to other restoration efforts where natural sediment is not easily accessible or feasible to collect in large quantities.

POSTER 16

Funding
DBI-2349548 NSF- REU Site Biological Discovery in Woods Hole

Abstract
The biology and behavior of many organisms are influenced by the daily cycle of light and dark. This response is controlled by the circadian oscillator, which impacts the sleep-wake cycle, hormone production, and behavioral patterns. We aimed to investigate how the circadian cycle impacts the sea star Patiria miniata, a model for reproduction and early development that lives in low oceanic intertidal zones. Studies had previously established that the core circadian oscillator cycles in mouse ovarian tissues. Additionally, as the main soft organ, the P. miniata ovary has been shown to adopt some functions generally assigned to the brain in vertebrates, so we investigated circadian gene expression in sea star ovaries. We collected ovary samples from two females at 4 hour intervals over a 24-hour period and analyzed expression of circadian oscillator, ovarian function, and melatonin-production-related genes using qPCR. We repeated this collection with one-week-old larvae to compare these results to the ovary samples. We found similar oscillation patterns of melatonin receptor 1B-A-like for both ovary samples and the larvae, and also found oscillation patterns for core circadian oscillator genes. Motivated by behaviors noted during the ovary collection and differences in the qPCR results between the two females, we wanted to look at movement patterns in light and dark periods. We used a GoPro to take images every five minutes for 65 hours and performed motion tracking for each individual. Most of the movement occurred in long, continued paths and the majority of stars traveled further in the light than dark. These results suggest that sea star gene expression and behavior are at least somewhat circadian, though not all genes are. Future studies could investigate a possible correlation between circadian gene expression and typical movement patterns on a single-animal level.

POSTER 17

Funding
DBI- 2349548   NSF- REU Site Biological Discovery in Woods Hole

Abstract
Biofilms are structured microbial communities with ecological and population dynamics similar to macrobiotic communities. Like trees within a forest, biofilms are also shaped by foundational species that have an outsized influence on the community structure and function. Here, we investigated the cellular lifecycle of Granulosicoccus, a bacterium known to be one of the most abundant and metabolically active organisms within the bull kelp (Nereocystis luetkeana) microbiome. Using live-cell time-lapse microscopy and fluorogenic probes, we visualized the cellular structure and cell division dynamics of Granulosicococcus biofilms. Airyscan super resolution imaging on a Zeiss LSM 990 microscope system revealed that the biofilm was composed of multiple cell types, including motile cells and symplasmata-like structures. Further long-term observation showed that Granulosicococcus divides by binary fission, with nucleoids replicating during each cell generation. Unlike typical bacterial division, binary fission was not coupled with a physical separation of cells, leading to the formation of multicellular aggregates. Our results extend the known range of marine bacterial cell lifecycles and will help future researchers explain how Granulosicococcus biofilm dynamics shape the bull kelp microbiome.

POSTER 18

Funding
Funding was provided by the Office of Naval Research and The Ben-Veniste Grell Family Foundation.

Abstract
Interest in invertebrate welfare is increasing as growing research demonstrates that environmental enrichment can influence behavior, physiology, and overall welfare in invertebrate species. Cephalopods are of interest given their complex nervous systems and growing use as laboratory models. Environmental enrichment may improve welfare by supporting species-typical behavior and reducing stress, but evidence-based recommendations remain limited. We evaluated whether tank enrichment affected exploratory behavior and habituation to a standardized stress challenge in Octopus bimaculoides and characterized the body patterns and behaviors observed during the challenge. Nine octopuses were assessed for baseline exploratory behavior using two behavioral assays: the time spent outside the den and the frequency with which they pursued a crab lure. Based on a composite exploratory behavior score ranging from low to high, octopuses were pair-matched and randomly assigned to enriched housing (den plus environmental enrichment, n = 5) or control housing (den structure only, n = 4). Each octopus was transferred to a barren aquarium for a 10-min stress challenge, during which deimatic and protean body patterns and behaviors were recorded, which was repeated once weekly for six weeks. Den-emergence and crab pursuit assessments were also repeated weekly to determine if there was an effect of enrichment over time on octopuses' exploratory behavior. Light-to-dark color change, long-mantle posture, and papillae expression all decreased significantly across weekly stress challenges in both groups. Environmental enrichment did not have a measurable effect on behavioral stress responses or changes in exploratory behavior. Instead, the changes observed in both groups were consistent with habituation to repeated testing and environmental tank conditions. This study provides a method for quantifying stress-related body patterns and behaviors expressed in laboratory octopuses and presents the first illustrated ethogram of stress-related body patterning during a standardized laboratory challenge to promote recognition of stress indicators in octopuses and improve laboratory animal care.

POSTER 19

Funding
WLW Externship, FAU.

Abstract
Seagrass meadows play an important role in providing habitat, supporting biodiversity, improving water quality, and stabilizing coastal sediments, but are increasingly being lost due to anthropogenic disturbances, making it essential to understand the conditions that promote the regrowth in degraded areas of Zostera marina (Eelgrass). Traditional moorings create scars in seagrass meadows due to their chains dragging across the seabed with changing winds and tides, uprooting vegetation and preventing recovery. In West Falmouth Harbor, many traditional moorings were replaced with conservation moorings in 2020, leaving bare spots in the eelgrass bed that have not fully regrown. This study examined sediment chemistry (bulk density and organic matter) in mooring-impacted areas to contrast spots where seagrass is regrowing from where it is not to understand the sediment conditions that drive successful eelgrass recolonization. Using sonar, mooring scars at various stages of recovery were identified, sediment cores were collected from recovering scars, unvegetated scars, and adjacent eelgrass beds to evaluate whether differences in sediment organic matter and bulk density influence eelgrass recovery. Bulk density and loss on ignition were measured through the top 8 cm of the sediment profile and analyzed in R Studio. We found no relationship between sediment organic matter or bulk density and the presence of new eelgrass growth within former mooring scars. It was surprising that neither sediment organic content nor bulk density was associated with eelgrass recolonization within mooring scars considering organic matter regulates sediment biogeochemistry, including sulfide accumulation and redox conditions, while bulk density is a proxy for sediment texture, distinguishing coarse sandy sediments from fine silt- and clay-rich sediments, which is known to affect seagrass health. Although these variables remain important indicators of sediment quality, our findings suggest that other chemical or physical characteristics play a more important role in determining where eelgrass can successfully reestablish.

POSTER 20

Funding
This work was supported by the University of Chicago Jeff Metcalf Summer Undergraduate Research Fellowship. This work was supported by the Marine Biological Laboratory 2026 McCarter Family Metcalf Fellowship.

Abstract
Many teleost fishes have facial appendages with diverse functions, and these functions are reflected in their anatomy. For example, the facial barbels of catfishes function in gustation, and are enriched in taste buds. Lionfish also have elaborate facial tentacles, but the function of these appendages is not known. In this project, we investigated the function of lionfish facial tentacles using comparative anatomy, histology, and immunofluorescence, comparing them with the well-characterized sensory barbels of two catfish species. Unlike catfish barbels, lionfish facial tentacles lack taste buds and therefore are unlikely to function in gustation. Instead, we find that these tentacles are extensively innervated with a central nerve, peripheral nerve fibers extending to the epidermis, and a synaptic marker expressed in both the core and periphery of the tissue. We also identify epidermal cells that express neural markers and that may represent a sensory cell type. Although lionfish facial tentacles have been proposed to function in disruptive camouflage, our findings suggest that they may also serve a previously unrecognized sensory function.

POSTER 21

Funding
University of Chicago Metcalf

Abstract
Identifying autonomous transposable element (TE) families and subfamilies in newly sequenced eukaryotic genomes remains slow and challenging. We present Hawkeye, a pipeline for rapid in silico detection and classification of autonomous TEs into families and subfamilies in unannotated genomes. Hawkeye uses known TE catalytic cores, characteristic of each TE superfamily, and identifies genome sequences that map to them. To do this, Hawkeye takes a list of known superfamilies and Position-Specific Scoring Matrices (PSSMs) of catalytic cores of known superfamilies of DNA transposons and retrotransposons, and uses psi-tblastn (position-specific iterative search against translated nucleotide database) to detect DNA sequences encoding amino acid sequences similar to the corresponding catalytic cores. These sequences can be viewed as internal parts of autonomous TE copies. They are then clustered with MMseqs2, an ultra-fast computational tool for grouping massive datasets based on sequence similarity. The clusters obtained are approximations of the families and subfamilies of TEs. These families and subfamilies are further characterized by comparing multiple alignments and the consensus sequences derived from them. The average identity (or equivalently, 1 minus divergence or Kimura distance) of a family/subfamily’s members to the consensus is used as an approximation of the family age. If a cluster is a subfamily, its consensus is ≥ 75% identical for over ≥ 75% of the length of its family consensus DNA sequence. By definition, a family is always older than its subfamilies. In clusters composed of 1 or 2 sequences, Hawkeye does not derive consensus sequences. However, these clusters are available in the output data set. Given that MMseqs2 is faster than RECON, used by RepeatModeler, the most popular TE detection tool, Hawkeye is expected to be faster than RepeatModeler. Given that psi-tblastn is more sensitive than tblastn/blastn, used by RepeatModeler, Hawkeye is expected to be more sensitive than RepeatModeler.

POSTER 22

Funding
Patel Lab

Abstract
Lepidoptera (butterfly) oogenesis (egg development inside the ovary) is controlled by a network of signaling pathways. Signaling pathways are chains of chemical reactions that allow cells to communicate, receive messages, and control vital actions like growth, movement, and death Most of what we know comes about lepidoptera oogenesis comes from studies in Drosophila. This is because Lepidoptera uses many of the same pathways, with some species-specific differences. Both Lepidoptera and Drosophila use many signaling pathways, and receptor proteins during development. In this experiment many signaling pathways, and receptor genes were probed for, these various pathways are what eventually code for wing and body growth, segmentation, and patterning of eyespots. However, it also does many things inside of the embryo and ovariole (maternal pattern genes) before and after fertilization. Not only do the genes do things on their own, but they also work together to do different, more complex tasks during body and wing development. this experiment will go look at the not just the role of the signaling pathways and receptor genes and how they work together, but also the maternal role in early development and the signaling pathways used pre and post fertilization embryos of different lepidoptera species.

POSTER 23

Funding
NSF-DBI2349548

Abstract
Burial occurs when an organism displaces sediment to fully or partially submerge itself into the substrate. The Northern Pufferfish, Sphoeroides maculatus, bury themselves in the sand to rest and protect themselves from predators. We investigated the kinematics and synchronization of body and fin undulations during burial in juvenile and adult pufferfish. Video analysis showed that during burial the fish will use its head and body to roll in the sand, then the fish will increase the undulation frequency of its caudal fin to fully (or partially) submerge itself in the sand. We quantified the duration of burial and frequency of body motion from high-speed videos. We performed statistical tests to determine the correlation between the fins and body movement. Our experiment focused on juvenile pufferfish who bury more readily; we believe this could be due to the smaller body size allowing for faster and more efficient transition into the sand. In both juvenile and adult pufferfish, the body rolling and tail undulation show strong synchronization with Q values being > 0.56 and associated with a p-value < 0.0001. Paired t-tests performed in R showed that the period of body rolling was shorter in duration than the following period of tail undulation, and the latter period showed an increase in tailbeat frequency. Our observations of the Northern Pufferfish show a clear two–step process in which the fish will perform a body roll and then use high frequency tail movement to submerge into the sediment.

POSTER 24

Funding
University of Chicago

Abstract
Little Pond is an urban estuary in Falmouth, Massachusetts with a small freshwater stream input at the north end and an inlet to the ocean on the southern end. Historically, the estuary received substantial nitrogen inputs from residential septic systems resulting in eutrophication. In 2016 the bordering neighborhoods were sewered, effectively lowering the N input. Since then, although ecological recovery has been observed, the response has been notably slow given the substantial reduction in external nitrogen inputs. Our hypothesis is that legacy nitrogen in the sediment slowly seeping back into the water column partially drives this slow ecosystem response. By analyzing the amount of legacy nitrogen and carbon buried in the sediment we can obtain data that could aid in future research on rates of eutrophication across the estuary. Sediment cores were collected along a longitudinal transect from the Northern parts of the estuary to the Southern inlet covering both vegetated and unvegetated areas. Each core was sectioned into multiple 1, 2, or 5cm intervals, and analyzed for carbon and nitrogen. The average nitrogen content across all cores was 0.67%N ranging from 0.12% to 1.12%, while the average carbon content was 6.49%C, ranging from 1.2% to 10.7%. These are relatively high concentrations and are consistent with organic-rich sediments in a eutrophic estuary. The C and N profiles showed no consistent changes with depth, the longitudinal transect, or between vegetated and unvegetated areas. Despite the substantial reduction in external N inputs following sewering 10 years ago, the expected decrease in N content toward the sediment surface was not apparent in the sediment profiles. These results indicate substantial carbon and nitrogen storage in Little Pond sediments, but no clear sedimentary signal of reduced nitrogen loading following sewering, highlighting the complexity of legacy nitrogen and its potential role in the estuary’s slow recovery.

POSTER 25

Funding
This work was supported by the University of Chicago Biological Sciences Collegiate Division Undergraduate Research Fellowship - Working with Non-Traditional Model Organisms in the Biological Sciences.

Abstract
Most animals need to establish an anterior-posterior (AP) axis during embryogenesis. In most flies, this process is initiated by a maternally deposited, anteriorly enriched mRNA of a transcription factor-encoding gene. In the fruit fly Drosophila, this transcription factor is Bicoid, which functions as the anterior determinant by activating the anterior part of the segmentation network. Despite its essential role, bicoid is only found in brachyceran flies and has been lost within this group multiple times, raising the question of how these flies establish their AP axis. Here, I investigate this question in a brachyceran fly that has lost Bicoid: the grey flesh fly, Sarcophaga bullata. To identify candidate anterior determinants, I used transcriptomic profiling of anterior and posterior egg halves, which revealed a small set of anteriorly enriched genes. I characterized their expression using RNA-seq datasets spanning multiple tissues and developmental stages, together with in situ hybridization chain reaction staining. These analyses identified a duplicated copy of the highly conserved ER translocation protein Sec62 as the strongest candidate anterior determinant because it is maternally expressed, anteriorly enriched, and its transcripts disappear after zygotic genome activation. We have named this gene Sec62like (Sec62L). Ongoing knockdown, knockout, and gain-of-function experiments will test whether Sec62L functions as the anterior determinant. If confirmed, Sec62L would represent the first known membrane protein to function as an anterior determinant, pointing to a previously undescribed mechanism of AP axis specification in flies.

POSTER 26

Funding
Edwin S. Linton Endowment Fund; Schmidt Sciences and the Foundation for Food and Agricultural Research.

Abstract
Halopelagic Sargassum is a group of three brown macroalgae (S. natans var. natans, S. natans var. wingei (sn8), and S. fluitans III) that grow in the Northwest Atlantic Ocean. Since 2011, a steady increase in Sargassum strandings on beaches have been reported in the Caribbean region. When washed ashore, Sargassum decomposes and affects nearby wildlife, ecosystems, and coastal communities. Transforming this excess Sargassum into a resource in the impacted countries could provide financial aid, as well as improve environmental conditions. A promising use for Sargassum is as an agricultural resource. This study focused on the biostimulant capacity of a mix of the three Sargassum species. We characterized the chemical composition from three extraction methods (autoclave extraction, alkaline extraction, and pressate extraction) by measuring antioxidant capacity, total phenolic content, protein, reducing sugar, carbohydrate, and mannitol concentrations. We compared these extractions to a commercially available biostimulant made from Ascophyllum nodosum, another type of brown seaweed that is known to improve plant growth. A second round of measurements were taken 2-3 weeks from the initial analysis to determine if any degradation occurred over time (i.e., shelf life). Preliminary results show that the alkaline and pressate treatment had a higher total phenolic content than the autoclave treatment, though significantly lower than that of the commercial A. nodosum biostimulant. Both the alkaline and pressate treatment had high carbohydrate and mannitol content as well, suggesting that these extraction methods could be the most effective for producing biostimulants with Sargassum. Total carbohydrate concentrations, along with antioxidant capacity and total phenolic content, reduced significantly two weeks from the initial measurements, indicating a short shelf life for Sargassum-based biostimulants.

POSTER 27

Funding
MBL

Abstract
Arthropod development is most commonly studied in Drosophila, but its segments form nearly simultaneously, making it difficult to study segmentation as a sequential process. Parhyale hawaiensis, a crustacean model organism, segments anterior-to-posterior like vertebrates, offering a valuable opportunity to study segmentation sequentially. This mode of segmentation differs from Drosophila and may represent an ancestral condition within arthropods. Parhyale is also easy to maintain and its embryos are readily accessible through non-invasive methods, further supporting its use as a model system.
This study investigates the role of Notch signaling in segmentation timing by treating embryos with the Notch inhibitor DAPT and examining how inhibition affects the timing and patterning of segment formation. Using Hybridization Chain Reaction (HCR), we visualized the expression of delta, even-skipped, odd-skipped, and hedgehog across staged embryos to assess how Notch inhibition alters segmentation dynamics relative to untreated controls. Future work will test a more potent Notch inhibitor, LY411575, to more precisely define Notch's contribution to segmentation timing.

POSTER 28

Funding
This work was supported by the University of Chicago Biological Sciences Collegiate Division Undergraduate Research Fellowship - Working with Non-Traditional Model Organisms in the Biological Sciences.

Abstract
Across many species, largely shared genomes can produce multiple discrete morphs. A well-known example is sexual dimorphism, in which gene regulatory networks direct the development of distinct male and female phenotypes across sexes. Wing patterning in swallowtail butterflies offers a compelling system to investigate the genetic basis of this phenomenon because closely related Papilio swallowtails include monomorphic, dimorphic, and polymorphic species. Previous studies have shown that the switches between Papilio wing-pattern forms in the subgenus Menelaides is controlled by a single gene, doublesex; however, how gene expression programs are modified to produce alternate morphs remains poorly understood. To characterize these developmental programs, RNA-seq analysis was performed using temporal gene expression data from hindwings of P. nephelus, a monomorphic species, and P. lowii, a sexually dimorphic and polymorphic species. The analyses focused on sex-biased expression within and between species. In both species, the late larval stage showed a high number of differentially expressed genes between males and females. Although this stage precedes visible wing pigmentation, wing specification and patterning has already begun, suggesting that late larval development may represent a critical window for sex differentiation. Surprisingly, P. nephelus had similar counts of DEGs to that of P. lowii suggesting that visibly subtle or non-obvious sexual dimorphism may depend on differential expression of key signaling molecules or transcription factors. Only 11 orthologous DEGs were shared between the two species. Among these, mirror shows a conserved expression pattern whereas Notch shows divergent expression across the species. To further investigate the role of these candidate genes, RNAi knockdown experiments will be performed in both sexes and species to assess their effects on the adult wing phenotype. To characterize the spatial expression patterns of mirror, Notch, and other DEGs, HCR will be performed across developmental stages, sexes, and species.  

POSTER 29

Funding
NSF REU - Plum Island LTER

Abstract
The soft-shell clam (Mya arenaria) is an infaunal bivalve native to the northwest Atlantic Ocean. For centuries, soft-shell clams have been an abundant food staple for local communities, allowing for the development of a robust shellfishing industry. Beginning in the 1940s, soft-shell clam populations began to plummet throughout the northeast United States. Local shellfishermen and officials attributed the decline to the range-expanding, invasive European green crab, Carcinus maenas. Local stakeholders in the Plum Island Estuary have raised concerns over soft-shell clam scarcity, where the drivers of population decline remain largely unknown. Therefore, this study investigates variation in larval supply and post-settlement mortality across the Plum Island Estuary, in Essex County, Massachusetts, and the possible mechanisms impacting the observed spatial variation. Mesh-covered boxes were set out along an estuarine gradient for a two-month period (May-July) to collect settling soft-shell clam larvae, which were then counted and measured. Soft-shell clam recruits were then outplanted throughout the estuary to observe possible mechanisms of spatial variation in recruitment. We found that post-settlement mortality played a significant role in soft-shell clam abundance in the lower and upper estuary zones, whereas minimal larval supply was a major driving force in the middle estuary. Potential mechanisms for the observed spatial variation include habitat suitability, temporal variation in recruitment, and differential predation pressures. These findings highlight that variation in larval supply and post-settlement mortality drive differential soft-shell clam recruitment throughout the estuary. Local stakeholders can use these results to inform public management decisions to protect and revitalize the soft-shell clam industry in the northeastern United States. 

POSTER 30

Funding
Funding came from the PIE LTER REU from the NSF

Abstract
Beaver ponds have become much more abundant in recent decades due to the resurgence of beaver populations. In beaver ponds, flooded organic material is broken down by microbes, creating methane. It is unknown how greenhouse gas emissions vary over space and time within the ponds. This study looks at the spatial variation of methane ebullition in a one-year-old beaver pond in Cart Creek, Newbury, Massachusetts. Methane ebullition volume was measured across a range of water depths (0.2m-0.5m) using funnels deployed during July-August 2026. The average daily volume of ebulliated methane was consistent over the four week period  at each site, but the volume varied between sites averaging 32.4 ml/day (ranging from 12.9 to 59.2 ml/day). There was no clear pattern between volume and water depth in the pond. This may be due to the presence of other uncontrolled factors, such as how recently the area was flooded or varying features of the pond (trees, rocks, etc.) impacting the distribution of organic material. These results indicate that the factors influencing methane emissions are complex and not fully understood. Given that greenhouse gas emissions from beaver ponds can be significant at a local scale, further research is necessary to explore this relationship.

POSTER 31

Funding
DBI- 2349548  NSF- REU Site Biological Discovery in Woods Hole

Abstract
Anthropogenic sounds have the potential to disrupt reproduction, feeding, and migration of aquatic organisms. Many boat motors overlap with fish auditory frequency sensitivity. Striped Bass, Morone saxatilis migrate to Eel Pond, Woods Hole, MA each spring and are impacted daily by boat sound. Fish interactions during sound playback and during operation of the research vessel Gemma were characterized using Garmin Livescope Forward-facing sonar to monitor fish presence, location, movement, and swimming speed. The ethogram constructed provides a non-invasive method to evaluate the auditory sensitivity of wild fish. Fish were exposed to pure tones (200 Hz or and 2000 Hz) that were followed by supplemental feeding. The sound stimulus played underwater for five minutes, and food was provided after one minute. The stimulus, food type, feeding interval, and a five-minute observation period before and after the acoustic cue, were kept consistent. Within four trials, an increased number of bass were present with 20 seconds of sound onset, prior to food delivery. After conditioning, fish ignored the 2000 Hz signal which was hypothesized to be outside the hearing range of the fish. The results indicate that fish impacted by anthropogenic sound retains hearing sensitivity and can be conditioned to associate sound with a food reward.  Future studies will test different frequencies and intensities to assess the hearing range of a wild population of striped bass.

POSTER 32

Funding
DBI- 2349548   NSF- REU Site Biological Discovery in Woods Hole

Abstract
Octopuses are highly curious animals that rely on their arms to explore and interact with their environment. Previous studies have shown that octopus suckers possess chemotactile and chemosensory capabilities, allowing them to detect chemical cues through direct contact and coordinate sensory information between neighboring suckers, other arms, and the central nervous system. Little is known about how these sensory cues influence arm recruitment during exploration. To investigate this question, we developed a behavioral assay using agarose gels infused with different chemical extracts. Results indicate that crab-infused agarose elicited the greatest number of arm recruitments. Recruitment occurred overwhelmingly within the distal region of the arms, while no preference was observed between anterior and posterior arm recruitment. Ongoing analyses of recruitment speed and the relationship between the initial contacting arm and the recruited arm will provide further insight into arm recruitment behavior, laying the groundwork for future studies of sensory integration in octopuses.

POSTER 33

Funding
NSF REU - Plum Island Ecosystems Long-Term Ecological Research

Abstract
Phytoplankton are the foundation of marine food webs, major contributors to global primary production, and indicators of environmental change. In coastal estuaries, understanding phytoplankton community composition (PCC) is important for ecosystem health and understanding processes affecting fisheries and harmful algal blooms. Evaluating strengths and limitations of various methods to characterize PCC is necessary for interpreting ecological patterns and identifying groups underrepresented by a particular approach. This study compares methods of assessing PCC in the Plum Island Estuary and Essex Bay, Massachusetts: size-fractionated chlorophyll-a concentrations via benchtop fluorometry, microscopy, and high-performance liquid chromatography (HPLC) pigments. Water samples were collected for chlorophyll and microscopy analysis in June-July 2026. A historical HPLC dataset collected from 2003-2025 was compared to Summer 2026 data. Sites showed considerable variability in phytoplankton size structure: no size fraction dominated across the estuary. Microscopy showed that as salinity increased, diatom abundance decreased while dinoflagellate abundance increased. This revealed a different pattern than HPLC data, which suggested that diatoms would dominate all sites in the summer. Despite differences in PCC, chlorophyll-a degradation was relatively uniform. While pigments can identify broad groups from all size fractions, they mask taxon-specific information seen through microscopy, particularly for groups that share pigments or have diverse feeding strategies. Microscopy was conducted with the 5x objective after sampling with a 64um phytoplankton net, preventing visualization of smaller size fractions of phytoplankton (<5um and 5-20um), which were assessed via fluorometry. This study highlights the importance of observing PCC across methods, as the microscopy data revealed a dinoflagellate population that was obscured by the HPLC data. Summer 2026 HPLC data will enable direct comparison with microscopy to evaluate pigment-based estimates of dinoflagellate abundance. Methods for characterizing PCC should be selected based on research questions, considering the strengths and limitations of each approach for identifying different components of PCC.

POSTER 34

Funding
NSF REU Plum Island Ecosystems Long Term Ecological Research

Abstract
The range of the Marsh Fiddler Crab (Minuca pugnax) has expanded north in the last 12 years due to climate shifts. Now, M. pugnax inhabit much of the coastal regions in the Gulf of Maine, including the Plum Island Estuary (PIE) in Massachusetts. Given that salt marshes are among the most productive estuaries, it is important to study active range expansions in these ecosystems. Our main goal was to identify the abiotic factors driving fiddler crab location within the salt marsh to further understand their impact on PIE. We conducted a 90 site survey of the upper, middle, and lower regions of PIE, taking measurements of percent habitat cover, soil compaction, elevation, and burrow density at each site. Data were analyzed using a generalized linear model and the distribution of ranges was assessed for each variable. Presence was not limited by any individually tested variable. Yet, a sediment compaction range of 1.25-3.5 kg/cm^2 was correlated with fiddler crab presence in all three PIE regions. At the estuarine level, the presence of S. alterniflora, S. patens, other vegetation, and bare ground all had no significant relationship with fiddler crab presence within the estuary. Although regionally, vegetation trends were observed in the upper and lower estuary. Soil compaction has the greatest impact on marsh fiddler crab presence in the PIE ecosystem. However, there are likely additional abiotic drivers influencing their presence. Overall, our results suggest fiddler crabs will likely expand further in PIE. Additionally, we’ve demonstrated how abiotic surveys can be applied to future range-expanding species which may be impacted by similar ecological variation.

POSTER 35

Funding
We thank the US National Science Foundation Chemical and Biological Oceanography Programs for their continuous support of the Oceanic Flux Program (OFP) time-series since 1978, most recently through NSF grant OCE 2122619, OCE 2414704 and OCE 2421112.

Abstract
Recently, Sargassum blooms have been increasing in size, causing coastal ecological and economic challenges, but not all Sargassum washes ashore. As Sargassum ages, it loses buoyancy and sinks, carrying its carbon, nutrients, and epiphytes to the deep ocean. Pelagic Sargassum supports diverse epiphytic communities, including carbonate-producing organisms such as bryozoans, serpulids, and goose barnacles. The Oceanic Flux Program mooring (OFP, 1978 - Present), located ~75km southeast of Bermuda, with sediment traps at 500m, 1500m, and 3200m, is ideally situated to intercept sinking Sargassum. This study evaluates the export of Sargassum over two decades (2004-2023) combining imaging, carbonate mass estimates and stable isotope analysis of the Sargassum epiphytes. Machine learning (Ilastik and FiftyOne) was used to quantify epiphyte area in the OFP images, which was then converted to dry mass using a calibration mass/area to estimate Sargassum epiphyte flux. Carbonate content of OFP-collected Sargassum-derived epiphytes was consistent across depth but varied by type, averaging ~72% in bryozoan, ~90% in serpulids and ~95% in goose barnacles. Carbonate δ13C and δ18O were similar across depth and varied by epiphyte type, suggesting differences in minerology and biomineralization. The absence of a depth effect in both carbonate content and isotopic composition indicates that sinking Sargassum fragments preserve the surface epiphyte community as they are exported to the deep. Bryozoan and serpulid carbonate fluxes can reach up to 0.2 mg m-2 d-1 during peak events. While both epiphyte types can impact the sinking rate due to their density, there is no significant covariance between bryozoan and serpulid fluxes. This study, together with our previous work focusing on the organic carbon export of Sargassum, provides the first evaluation of the contribution and composition of Sargassum-derived carbon to the deep ocean.

POSTER 36

Funding
This work was supported by the University of Chicago Biological Sciences Collegiate Division Undergraduate Research Fellowship - Working with Non-Traditional Model Organisms in the Biological Sciences.

Abstract
Mechanotransduction, the conversion of mechanical stimuli into cellular signals, underlies essential sensory functions including hearing, touch, and balance. In vertebrate hair cells, mechanical force is transmitted to mechanotransduction (TMC) channels through extracellular tip links composed of Cadherin-23 (CDH23) and Protocadherin-15 (PCDH15). Previous studies demonstrated that cnidarian mechanosensory cells possess hair bundle-like structures and TMC5/7-dependent mechanotransduction, suggesting that key components of this machinery may have originated before the evolution of vertebrates. However, the molecular identity of the extracellular tether in cnidarians has remained unknown.

In this study, we investigated the evolutionary conservation of tether-based mechanotransduction in jellyfish nematocytes by identifying candidate tip-link proteins. Transcriptomic and bioinformatic analyses identified cadherin and protocadherin homologs through differential expression analysis, homology searches, phylogenetic reconstruction, protein domain annotation, and structural prediction. Candidate genes were cloned into fluorescent expression constructs and introduced into jellyfish embryos by microinjection to examine their subcellular localization within the stereovillar bundle using fluorescence microscopy. In parallel, RNA interference (RNAi)-mediated knockdown constructs were generated and delivered by microinjection to evaluate the functional roles of candidate genes in mechanotransduction. Functional analyses, including FM dye uptake, nematocyst discharge, and hair bundle morphology assays, are currently underway.

Together, these computational and experimental approaches established a framework for identifying and functionally characterizing candidate extracellular tether proteins in cnidarians. This work provides a foundation for testing whether cadherin-based tether mechanisms predate vertebrate hearing and offers new insights into the evolutionary origins of animal mechanosensation. 

POSTER 37

Effects of Syn3 on Neuronal Ion Current and Membrane Potential Activity
Ava Yu (MBL, Kenyon College), Elizabeth Jonas (MBL, Yale University), Liman Liu (Yale University)

Funding
NIH/NINDS

Abstract
Brain-derived neurotrophic factor (BDNF) is one of the most important proteins in supporting synaptic growth and survival. Reduced BDNF signaling was previously shown in the development of diabetic retinopathy and has been suggested to contribute to the pathophysiology of depression as well as neurological disorders such as Angelman syndrome. Subsequently, the neuroprotective cyclic peptide Syn3 (synapsin-3) was developed as a BDNF signaling enhancer that targets the tropomyosin receptor kinase B (TrkB)/postsynaptic density protein-95 (PSD-95) in the BDNF signaling pathway. Syn3 and similar peptidomimetic compounds were recently demonstrated to alleviate retinal cell ganglion degeneration in diabetic retinopathy and improve seizure outcomes in an Angelman syndrome mouse model.

In this experiment, we performed single-cell patch clamp electrophysiology on control and Syn3-treated rat hippocampal neurons to determine if changes occur in ion channels or membrane potential activity between the two groups over a 72-hour time course. Each cell was recorded with a voltage clamp to measure ion current flow at a steady membrane potential, and a current clamp to measure cell excitability via fluctuations in membrane potential with consistent current injections. Preliminary data show slight increases in potassium current and action potential firing rates in the Syn3-treated cells. However, continued data collection and further analysis is needed to determine the long-term effects of the drug in neuronal membrane potential patterns and channel activity.

POSTER 38

Funding
University of Chicago Biological Sciences Collegiate Division Undergraduate Research Fellowship - Working with Non-Traditional Model Organisms in the Biological Sciences

Abstract
The molecular mechanisms underlying trait gain in wild species remain less understood than those underlying trait loss. To address this, our lab has been developing sea robins as a new research organism. Sea robins are saltwater fish that exhibit intriguing evolutionary innovations, including expanded, wing-like pectoral fins and leg-like structures that allow the fish to walk and taste for food. We crossed two sea robin species to produce hybrids and to explore the genetic basis of species-specific differences, including significant pectoral fin size variation. RNA-sequencing and allele-specific expression analysis on the pectoral fins of both species and hybrids showed that aldh1a2, a gene involved in retinoic acid synthesis, was upregulated in the species with larger pectoral fins and is regulated in cis-. Notably, aldh1a2 appears to promote increased forelimb size in other species, while reduced expression correlates with smaller wings in the emu. When we disrupted aldh1a2 in sea robins using CRISPR-Cas9 editing, we found that larvae developed without pectoral fins. Using zebrafish ATAC-sequencing data, we identified putative enhancers downstream of aldh1a2 that are conserved in sea robins but show marked sequence divergence in the species with enlarged pectoral fins. Intriguingly, we also identified a large insertion in this species immediately downstream of aldh1a2, comprising an 89bp sequence repeated 400 times in tandem. To test for regulatory activity, we will clone putative enhancer sequences and the repeat array upstream of a minimal promoter driving GFP, inject into sea robin embryos, and assay reporter expression. We will also use CRISPR-Cas9 editing to perturb these regions to assess their in vivo contribution to pectoral fin development. Together, these studies will provide a mechanistic understanding of how variation in noncoding elements can contribute to evolutionary innovations.

POSTER 39

Funding
DBI- 2349548   NSF- REU Site Biological Discovery in Woods Hole

Abstract
Cuttlefish rely on rapid body pattern changes for both camouflage and secondary defensive displays, such as deimatic patterning (threat/startle displays). One such pattern, the Fragmented Dark Mantle (FDM) is a high-contrast pattern component that has been identified in Acanthosepion pharaonis. While this component has not been fully contextualized, this type of high contrast patterning is most often observed in deimatic displays. The FDM has been reported to be routinely expressed during cuttlefish prey capture and has been observed anecdotally in our lab in scenarios where the animal is presented with a disturbance. In this study, we attempt to determine the frequency, duration, and intensity of the FDM in different contexts and to gain an understanding of the evolutionary purpose of this component. To do this, three late juvenile cuttlefish were tested across three repeated trials in four conditions: 1) prey, 2) predator, 3) both prey and predator, and 4) control. Animals were filmed during each trial and FDM expression was scored over time based on pattern intensity, identified as contrast multiplied by definition. Here we show that significant differences were found in FDM intensity score per trial between the control condition and prey and predator condition (p = .027). There were also differences in the amount of time that the FDM was expressed at different contrast levels across conditions, with high contrast showing a significant difference across conditions and moderate contrast approaching significant differences across conditions. Our findings suggest that the Fragmented Dark Mantle functions as a deimatic display that is expressed at its highest intensity when both prey and predator are present simultaneously. This is consistent with the idea that cuttlefish increase threat displays during periods of heightened vulnerability, such as while capturing and eating prey.