Zooplankton are fundamental to aquatic ecosystems, influencing not only biogeochemical cycles but also broader ecological dynamics. As primary consumers, they link lower trophic levels, such as phytoplankton, to higher trophic levels, including fish and other predators, thereby shaping food web structures. This session will delve into the ecological roles of zooplankton across aquatic environments, with a focus on their contributions to biogeochemical cycles and their adaptive responses to environmental changes.
In both marine and freshwater systems, zooplankton contribute to carbon cycling through the biological pump. They graze on phytoplankton, respire carbon dioxide, and repackage organic matter into fecal pellets that can sink to deeper waters or sediments, a process crucial for sequestering atmospheric carbon dioxide. Additionally, zooplankton excrete dissolved inorganic nutrients that are rapidly assimilated by phytoplankton, sustaining primary production in nutrient-depleted areas.
We invite contributions on the latest findings in zooplankton ecology, including their distribution, behavior, and interactions with other organisms in both marine and freshwater ecosystems. The session will also encompass studies on zooplankton-mediated carbon and nutrient cycling, examining factors that influence export efficiency, such as species traits, community dynamics, and environmental changes like climate change, ocean acidification, and deoxygenation.
The session will also highlight cutting-edge methodologies advancing our understanding of zooplankton ecology. Innovations in imaging, molecular tools, and biogeochemical modeling are providing new insights into zooplankton distributions, behaviors, and ecological roles. We encourage presentations showcasing these technologies and their applications in contemporary research.
This session aims to synthesize current knowledge, identify research gaps, and prioritize future studies in zooplankton biogeochemistry. We will explore how these small but ecologically vital organisms can be integrated into global biogeochemical models, with implications for climate predictions and resource management.
By bringing together experts in aquatic biology, ecology, limnology, oceanography, and biogeochemistry to foster interdisciplinary collaboration. It is designed to attract researchers, educators, policymakers, and students focused on the ecological and biogeochemical roles of zooplankton and their responses to environmental change. Through this exchange, we aim to deepen our understanding of the ecological importance of zooplankton and their role in maintaining healthy aquatic ecosystems.
The session’s importance lies in its potential to advance our understanding of the critical roles zooplankton as ecological keystones in aquatic environments. As we face unprecedented environmental challenges, it is crucial to integrate zooplankton ecology into broader scientific frameworks to preserve aquatic biodiversity and ensure the sustainability of global biogeochemical cycles.
Lead Organizer: Yuuki Niimi, Arizona State University (yniimi@asu.edu)
Co-organizers:
Leocadio Blanco-Bercial, Arizona State University/Bermuda Institute of Ocean Science (leocadio@asu.edu)
Susanne Neuer, Arizona State University (Susanne.Neuer@asu.edu)
Presentations
06:00 PM
Seasonal water column stratification drives the ontogeny of pelagic tunicates in shallow shelf systems (9725)
Primary Presenter: Laura Treible, Savannah State University (laura.treible@gmail.com)
Pelagic tunicates, including salps and doliolids, can substantially impact microbial processes, carbon cycling, and the fate of primary production in continental shelf systems. However, the mechanisms behind their capacity to form blooms remain unclear. The precise oceanographic conditions experienced by these animals and their vertical migrations throughout ontogeny are needed to resolve the environmental drivers of their location, patchiness, abundance, and transport. To fill this knowledge gap, an in-situ imaging system was deployed in the northern Gulf of Mexico (nGOM) during the fall and summer of 2015-2016. The nGOM undergoes a seasonal shift from highly stratified summer conditions to fully mixed waters by mid-fall, making this location ideal to examine the impacts of vertical water column structure on salp and doliolid distributions. Images from multiple transects were manually classified into different life stages, including doliolid gonozooids, phorozooids, and nurses, and individual salps, salp rings, and chains. In summer, salps were consistently located within and around the pycnocline, regardless of their life stage. In contrast, doliolid stages showed distinct vertical distribution, with gonozooids and phorozooids primarily found above the pycnocline, and most nurses deeper in hypoxic (<2 mg/L) bottom waters. Even in the well-mixed conditions in fall, doliolids preferred deeper waters further offshore, suggesting that their patchiness is influenced by factors beyond vertical oceanographic structure.
06:00 PM
Understanding Zooplankton Community Dynamics and Functional Diversity (9496)
Primary Presenter: GABRIELLE Corradino, Barnard College of Columbia University (gabrielle.corradino@gmail.com)
To assess the ecological significance of zooplankton in Florida’s Central Atlantic, this study examined the community structure and copepod functional diversity of surface (1-6m) tow samples (n = 133) collected in 2021 and 2022. Our findings reveal a diverse plankton community dominated by adult copepods, with significant contributions from bivalve larvae, larvaceans and chaetognaths. Within the copepod fraction the genera Acartia, Nannocalanus and Paracalanus were the most common across both sampling seasons. Functional diversity analysis, based on 16 functional entities, provides additional insights into the ecological roles of copepods. Functional diversity indices and functional space were similar across the two years, although community composition changed. By understanding the dynamics of zooplankton communities, we can better appreciate their crucial roles in marine food webs and biogeochemical cycles, ultimately contributing to the preservation of healthy and resilient coastal ecosystems.
06:00 PM
THE GENERATIONAL EFFECTS OF TEMPERATURE AND VISCOSITY ON FRESHWATER COPEPOD BODY SIZE (8832)
Primary Presenter: Zachary Wagner, Georgia Institute of Technology (zwagner7@gatech.edu)
Bergmann’s Rule is an ecogeographical theory that states that closely related organisms will be larger in higher latitudes than those of lower latitudes. Copepods, small crustacean zooplankton that live at Intermediate Reynolds Numbers, closely follow this trend. While temperature is often stated to be the major driver behind this trend in body size, one little studied variable linked to temperature is viscosity. To test the effects of viscosity on copepod body size, two lineages of subtropical, freshwater Mesocyclops sp. copepods were grown for five generations in cultures of differing temperatures, 30C and 18C, and viscosities, natural and altered to mimic 18C while at 30C. Adult females were collected and measured, and their nauplii used to begin the next culture, the process repeated for each generation. It was found that copepods grown at 30C were on average 13.20% smaller than those grown at 18C, regardless of viscosity. Copepods grown in 30C cultures with the viscosity of 18C had no body size differences when compared to copepods grown at 30C and natural viscosity. Additionally, Mesocyclops sp. reached sexual maturity after 9 days while grown at 30C, and 11 days while grown at 18C, with viscosity playing no role in maturation time. This study provides further support for temperature driving copepod body size, with the physics of the environment playing no role in the body size of these small organisms. This is especially surprising due to copepod movement, feeding, and sensory ecology being reliant on the viscous properties of water.
06:00 PM
COPEPOD-PROTIST INTERACTIONS ALONG ENVIRONMENTAL GRADIENTS WITHIN THE GULF OF MEXICO DURING SUMMER AND FALL OF 2021 (9455)
Primary Presenter: Will McClure, North Carolina State University (wtmcclur@ncsu.edu)
Copepods are important consumers of primary producers and primary consumers within the marine ecosystem. Most copepods operate as omnivorous suspension feeders that ingest varying protists, small metazoans, and detritus. In turn, these crustaceans provide an important food source for higher trophic levels, facilitating transfer of energy to a variety of consumers including fish, shellfish, seabirds, and mammals. Assessing natural copepod diets can be a complex task due to their ability to feed on a wide variety of prey. Copepods may also select for prey or adjust their feeding strategies in response to a changing prey environment. This study characterizes copepod-protist trophic interactions in mesotrophic nearshore and in oligotrophic offshore waters from shipboard incubations conducted on the Gulf of Mexico Ecosystems and Carbon Cruise (GOMECC-4) in September-October 2021. The goal of this study was to contribute to our understanding of protist-copepod dynamics in the Gulf of Mexico and explore potential trends in copepod grazing related to environmental gradients. Particle analysis for prey abundance and biovolume calculations was conducted using fluid imaging microscopy (FlowCam). Carbon-based copepod ingestion rates and estimates of copepod community grazing are further discussed in relation to prey carbon stocks and prey community structure. Dissolved oxygen was the most significant driver in explaining variability in the prey community across environmental gradients, with trophic index being a major factor in impacting copepod ingestion rates.
06:00 PM
TRAIT-BASED INSIGHTS INTO COPEPOD MIGRATION: THE ROLE OF SIZE AND TRANSPARENCY IN DVM BEHAVIOR (9217)
Primary Presenter: Rocio Rodriguez Perez, Arizona State University (rocioblrodriguez@gmail.com)
Copepods play a vital role in marine ecosystems, particularly in carbon export through Diel Vertical Migration (DVM). Traditionally, body size has been recognized as the primary factor influencing DVM amplitude, with larger copepods undertaking more pronounced vertical migrations. However, other morphological traits, such as transparency, may also affect DVM behavior. In this study, we explore the role of transparency, a less commonly considered trait, in shaping migration patterns. Using MOCNESS tows and ZooScan imaging, we quantified a range of morphological descriptors to assess copepod community structure and distribution. Our findings reveal that both size and transparency related variables are significant factors influencing DVM. While size remains a key determinant of DVM amplitude, we found that transparency is also closely linked to migration depth. More transparent copepods face reduced predation risk, allowing them to stay closer to the surface. Interestingly, while size-related DVM amplitude varied across regions, transparency-related migration patterns were consistent, suggesting it is a more conserved trait. These results emphasize the importance of incorporating both size and transparency into ecological models to better understand zooplankton behavior and their contributions to biogeochemical cycles.
06:00 PM
OPTIMIZING DNA PRESERVATION METHODS FOR MOLECULAR GUT CONTENT ANALYSIS STUDIES IN FIELD COLLECTED GELATINOUS ZOOPLANKTON (9046)
Primary Presenter: Alyssa Fritz, University of Georgia (alyssa.fritz@uga.edu)
Molecular gut content analysis (MGCA) is a commonly utilized approach for assessing the diet of a variety of animal species. MGCA is especially appropriate for assessing the cryptic diets of small consumers including insects and aquatic and marine zooplankton species. MGCA approaches typically involve extracting DNA from the consumer followed by sequence-based identification of non-host DNA. As it is often not practical in remote field conditions to purify and store extracted DNA, preservation for MGCA analysis is often required. In this study the efficacy of two tissue stabilizing solutions containing chaotropic salts were investigated for eventual use in investigating the diets of enigmatic marine pelagic tunicate species whose trophic ecology is poorly understood. In these studies, two commercially available tissue stabilization solutions were investigated and their extraction efficiencies and suitability with commercially available DNA purification protocols explored. Tissue preservation solutions included Zymo Research DNA/RNA Shield™ and Qiagen’s AllprotectTissue Reagent. Initial results suggest that these solutions do not greatly hinder the quality or quantity of DNA extracted from samples after being submerged in either solution. Further experiments incorporating more biological variation are being explored to identify the optimal method for DNA preservation in future MGCA studies in gelatinous zooplankton.
SS44P - Ocean and Freshwater Zooplankton Ecology
Description
Time: 6:00 PM
Date: 29/3/2025
Room: Exhibit Hall A