Contributed Session.
Lead Organizer: Remington Poulin, University of North Carolina Wilmington (poulinr@uncw.edu)
Presentations
09:00 AM
Effects of host-introduction events on the dispersal and diversity of eukaryotic and prokaryotic microbial communities in the marine animal host Delphinapterus leucas (9608)
Primary Presenter: Susan Smith, Sea Research Foundation, Mystic Aquarium (susan.smith@uconn.edu)
Megafaunal hosts offer a unique evolutionary context in the global transport and distribution of their microbial symbionts in the marine environment. However, little is known regarding the transmission of host-associated microbes among host individuals as climate change dynamics increase population overlap. The following project combines prokaryotic and eukaryotic microbiome analyses to elucidate microbial transfer between marine animal hosts when they are confronted with the introduction of a new host population. Using beluga whales (Delphinapterus leucas) as a representative marine animal host maintained under professional human care and taking advantage of a sampling regime surrounding controlled host introduction events, this study evaluated the dynamics of microbial interchange with sociality between resident and introduced hosts over time. Analyses includes oral, blowhole, and respiratory exhalate samples from D. leucas individuals taken: (1) Prior: samples taken from initial hosts prior to arrival of new hosts; (2) Arrival: samples taken continually within days of introduction event, and (3) Post-Habitation: samples collected bi-monthly (2x/30 days) extending twelve months after study initiation. Samples also include water collected from the habitat throughout the study period. While preliminary, this study enhances our understanding of host-associated transmission and dispersal of host-associated microbes in the marine environment.
09:15 AM
Development and Validation of Quantitative PCR Assays for Detecting and Monitoring Caribbean Spiny Lobster (Panulirus argus) in Environmental DNA Samples (9391)
Primary Presenter: Reneisha Sweet, Jackson State University, Jackson, MS (J00836759@students.jsums.edu)
The Caribbean spiny lobster, Panulirus argus, which inhabits waters on the southeastern coast of the United States and is particularly abundant in the seagrass and coral reef habitats of South Florida, is an important commercial and sport fisheries species throughout the region. In recent years, populations of P. argus have declined by more than 50%, which is believed to be due, in part, to habitat degradation. Monitoring the population of the Caribbean spiny lobster is crucial for effective conservation and fisheries management efforts; however, traditional methods for assessing the abundance of P. argus, including catch-per-unit effort (CPUE) analyses and visual surveys, are dependent upon the accuracy of fisheries data and can be costly due to high labor costs associated with visual surveys. Here, we present two probe-based qPCR assays targeting the COI and 16S rDNA gene regions in P. argus and demonstrate their use for a non-invasive eDNA-based approach to supplement traditional methods for monitoring the abundance of P. argus. After validation using mesocosm eDNA samples with gBlocks spike-ins of known concentrations, these probes were used to characterize the abundance of P. argus DNA in 36 samples from 12 sites in Florida Bay using both qPCR and dPCR. The results of these analyses were compared to the results of visual surveys conducted by FWRI at the time of sample collection. Initial results suggest that P. argus DNA can be identified in eDNA samples. Still, additional samples from abundant sites are needed to clarify the correlation between eDNA and lobster abundance.
09:30 AM
Integrating DNA Metabarcoding with Morphological Identification for Comparative Analysis of Extraction and PCR Protocols (9427)
Primary Presenter: Kambrial Love, Jackson State University (J00828901@students.jsums.edu)
Phytoplankton are critical in shaping global biogeochemical cycles through the uptake of carbon and inorganic compounds, as well as the production of oxygen. Traditional assessments, relying on microscopy, require considerable taxonomic expertise and often fail to document the genetic diversity within phytoplankton communities. DNA metabarcoding offers a promising alternative for assessing community composition, though inconsistent sampling protocols hinder cross-study comparisons. Here we examine the effects of DNA extraction replication on assessing community composition and the detection of rare species in phytoplankton communities using DNA metabarcoding in samples collected from the Ocean Springs Harbor Pier in Ocean Springs, MS. Prior to DNA extractions, replicate plankton samples were either divided into thirds before extraction or maintained as a single volume for DNA extraction. Each sample was then metabarcoded using two loci (i.e., rbcL, and 23S). Results from the metabarcoding analysis are compared between those amplified from 1/3rd sample DNA extractions and full volume DNA extractions and estimates of community composition determined for each. These results are then compared with community composition estimates from traditional morphological analyses conducted at the Hollings Marine Lab in Charleston, SC, to evaluate the strengths and limitations of each approach. Results suggests that metabarcoding of multiple smaller extractions yields a more diverse community estimate, but it is unclear if the substantially higher costs are justified. Keywords: Phytoplankton, DNA metabarcoding, DNA extraction, PCR replication, sequencing depth, phytoplankton community composition, morphological identification, ecological assessment
09:45 AM
IMPACT OF WARM-CORE EDDIES AND DIEL VERTICAL MIGRATION ON ZOOPLANKTON DISTRIBUTIONS (9397)
Primary Presenter: Annette Govindarajan, Woods Hole Oceanographic Institution (afrese@whoi.edu)
The ocean’s mesopelagic, or twilight, zone is critically important to biogeochemical processes influencing Earth’s climate. Through their feeding and migratory behaviors, mesopelagic zooplankton play key roles in the biological carbon pump, which transfers carbon from the surface ocean to the deep sea where it is sequestered. However, more information is needed on zooplankton species diversity and factors affecting their distributions. The goals of this study were to determine the impact of a warm-core eddy on zooplankton diversity and vertical distributions in the Northwest Atlantic Ocean. The study takes advantage of depth-stratified MOCNESS zooplankton tows conducted in neighboring Slope Water stations during a 2019 oceanographic cruise on the NOAA Ship Henry B. Bigelow, with different water mass characteristics reflecting the influence of a warm-core eddy in one of the stations. Two nighttime and two daytime tows were conducted in the eddy-influenced sampling station and two nighttime and one daytime tow were conducted in a nearby area outside the influence of the eddy. DNA metabarcoding of the species-specific COI barcode marker was conducted on the net contents. We found that that the eddy-influenced station had greater species richness, reflecting the mixing of animal communities of different origins. We additionally determined the daytime and nighttime depth distributions of the different species and identified typical as well as many reverse vertical migrators. We discuss the implications of our findings for understanding mesopelagic zooplankton functional roles.
10:00 AM
Automated imaging in Long-Term Ecological Research reveals taxon-specific bloom anomalies in phytoplankton (8896)
Primary Presenter: Heidi Sosik, Woods Hole Oceanographic Institution (hsosik@whoi.edu)
Coastal pelagic waters support complex and dynamic ecosystems that depend on planktonic food webs. These systems are challenging to observe at the appropriate spatial, temporal, and taxonomic scales. We are working to meet this challenge with automated microscopic imaging at the Northeast U.S. Shelf Long-Term Ecological Research (NES-LTER) site. For over a decade, we have deployed Imaging FlowCytobot both at a nearshore cabled observatory and on-board research vessels surveying across the shelf seasonally. With this vast dataset (>1.5 billion images) and machine-learning for image classification, we are now able to document where and when unusual blooms of specific taxa or groups of phytoplankton occur. These atypical blooms are surprisingly common in the dataset, but also highly variable both in which taxa occur and in spatial and temporal location and extent. This presentation will highlight examples of decade-scale outlier abundances of specific diatoms, dinoflagellates, and haptophytes. We will show that some events appear to be nearshore phenomena with timescales of weeks while others are localized in mid- or outer- shelf waters over similar timeframes, and furthermore that certain massive, unprecedented blooms can persist for months and extend over 100s of kilometers along the NES. While we have an evolving understanding about factors promoting some of these types of blooms, in many cases they remain mysterious to explain.
CS04 - Biodiversity
Description
Time: 9:00 AM
Date: 28/3/2025
Room: W208