Jellyfish (cnidarian subphylum Medusozoa and phylum Ctenophora) exist since the Cambrian period. Since then, these members of gelatinous zooplankton have developed various life forms and lifestyles, which enables them to dwell in nearly all habitats of the global ocean. Recent reports on the local and regional increase of jellyfish blooms, triggered debate over the actual cause and consequences of observed fluctuations and dragged the attention of broader scientific community, resulting in mount of evidence on the role, importance and impacts of jellyfish in global ocean ecosystem. At the same time, studies exposed numerous knowledge gaps, which we need to address to accurately integrate jellyfish and jellyfish-derived organic matter into marine food webs, biogeochemical budgets and models. We propose a very broad jellyfish session that brings together researchers from different disciplines to examine jellyfish and related topics from different perspectives filling recognized knowledge gaps. This session welcomes studies that examine jellyfish diversity, distribution, physiology, behaviour, and ecology, their interactions with other members of the marine food web, especially with microbes and jellyfish potential predators, with particular emphasis on studies that use e-DNA, omics approaches and microscale analyses. We seek applied research on advances in jellyfish observation techniques (from remote sensing to systematic transects, drone observations, underwater cameras, ROVs and Citizen Science) and efforts to establish common monitoring standards and criteria. Studies employing all types of modelling, including fluid dynamics, ecosystem models, individual-based models, Lagrangian models, probabilistic models, coupled physical-biogeochemical models, providing insights into jellyfish dynamics and dispersion on local, regional and global scales, are welcomed. Research investigating the causes and consequences of jellyfish blooms for ecosystem functioning, food web structure, biogeochemical state of marine ecosystems, and the role of jellyfish in marine ecosystem services are seeked. We are interested in studies understanding jellyfish in the past (including fossils) and in the context of future changes in oceanic habitats related to increases in seawater temperature, changes in salinity, nutrient regimes, ocean dynamics, ocean sprawl (offshore platforms, aquaculture facilities, wind farms), and the introduction of non-indigenous species. Last, but not least, we want to welcome research tackling jellyfish and human interaction, from the valorisation of jellyfish, as food or fertilisers and in cosmetics and pharmacology as potential producers of bioactive molecules, to the effects of jellyfish on human health and well-being and jellyfish in history, art, and popular culture.
Lead Organizer: Tinkara Tinta, National Institute of Biology (tinkara.tinta@nib.si)
Co-organizers:
Martin Vodopivec, National Institute of Biology (Martin.Vodopivec@nib.si)
Laura Prieto, Instituto de Ciencias Marinas de Andalucia (laura.prieto@icman.csic.es)
Mohamed Najib Daly Yahia, Qatar University (nejibdaly@qu.edu.qa)
Presentations
06:30 PM
Modeling of jellyfish fragmentation and its impact on vertical and lateral mass distribution during settling process (4777)
Primary Presenter: Matjaz Licer, Slovenian Environment Agency, National Institute of Biology (matjaz.licer@gmail.com)
We report on an influence of jellyfish fragmentation on vertical and lateral distribution of its mass during settling period. Jellyfish organism is modeled as a sphere with density which is 0.1% higher than the density of seawater. Organism fragmentation is modeled as a recursive decay of each existing fragmented particle into N new particles, but following exponential mass distribution over all fragmented masses. Strict mass conservation is enforced during each fragmentation event. Decay probability scales as a nonlinear function of mass so that more massive particles decay with larger probability. Vertical settling velocity of each fragment is computed as the terminal velocity of the respective buoyant particle in the linear Stokes drag regime. It scales nonlinearly with mass, making more massive particles sink faster, leading to a vertical dispersion of mass and particle distribution. Settling velocity of the mass distribution maximum seems consistent with reported estimates. Horizontal currents are simulated as a linear combination of semi-diurnal and diurnal tidal signals, perturbed by a stochastic component of similar amplitude. We simulate an ensemble of scenarios over a broad range of decay probabilities, fragmented mass distributions and circulation regimes. This allows us to estimate that fragmented organism in an ocean of 4000 m depth may take hundreds of hours to sink in its entirety. Horizontal distribution of fragmented matter may reach radiuses of several kilometers. Both numbers represent a substantial departure from a non-fragmented terminal velocity settlement of a single organism.
06:30 PM
DECAY OF GELATINOUS ZOOPLANKTON BLOOMS TRIGGERS CONSISTENT METABOLIC REPONSE OF SPECIFIC BACTERIAL TAXA IN COASTAL MARINE ECOSYSTEMS (4832)
Primary Presenter: Tinkara Tinta, National Institute of Biology (tinkaratinta@gmail.com)
Blooms of gelatinous zooplankton represent rapid and significant build-up of protein-rich biomass, inducing major perturbation to the marine ecosystem. These blooms often collapse en masse leading to a release of large amount of labile detrital organic matter (OM) into ambient seawater. We conducted two microcosms experiments, simulating the scenario experienced by coastal bacterial communities after the decay of the jellyfish (Aurelia aurita s.l.) and ctenophore (Mnemiopsis leidyi) bloom in the northern Adriatic Sea. Despite fundamental genetic, biochemical and life history differences between the two gelatinous organisms, high similarities in the metabolic responses of the ambient bacterial communities were observed. Combined metagenomics and metaproteomics analysis revealed that the bacterial consortium degrading both types of gelatinous detritus was dominated by Pseudoalteromonas exhibiting high production of proteolytic exoenzymes and elevated metabolic activity. Interestingly, despite the two experiments were carried out in different years, we were able to reconstruct an almost identical metagenome-assembled genome (nucleic identity >99%) of Pseudoalteromonas phenolica dominating both datasets. Taken together our data suggest that similar to well-studied phytoplankton, also gelatinous blooms likely trigger a consistent response of natural bacterial communities, however, supporting faster growth rates and higher bacterial growth efficiency than phytoplankton-derived OM.
06:30 PM
Stressed out! Jellyfish Developmental and Morphological Responses to Rising Temperatures (4862)
Primary Presenter: Dewi Ford, University of Chester (dewi.ford@gmail.com)
As anthropogenic stressors increasingly impact our oceans, jellyfish may become more prevalent within marine communities, which has a number of ecological and socio-economic implications. This draws our attention to how future climate scenarios will influence jellyfish physiology, and therefore the likelihood of population sizes rising in upcoming years. However, experimental data demonstrating how environmental stressors influence jellyfish physiology is limited. Data considering the potential influence of global warming on growth, behaviour, and morphology of the scyphozoan jellyfish Cassiopea sp. will be presented. Following strobilation, individual development and a suite of morphometrics were tracked over a three-month period. This data is used to assess plasticity and resilience to environmental parameters in relation to climate change. These parameters are also evaluated in Cassiopea sp. reared in darkness to assess of how temperature effects vulnerability to an additional stressor. Finally, environmental drivers of jellyfish morphology that may be considered for taxonomic research are highlighted.
06:30 PM
Mapping the Current and Future Distribution of Arctic Jellyfish (5334)
Primary Presenter: Dmitrii Pantiukhin, Alfred Wegener Institute (dmitrii.pantiu@gmail.com)
The Arctic Ocean is undergoing significant environmental changes that are altering the functioning of its ecosystems. Gelatinous zooplankton (GZ), commonly known as jellyfish, are an important component of the Arctic marine food web. Despite their importance and abundances, GZ remain largely ignored in pelagic studies, challenging predictions on their role and impact in the future state of the Arctic ecosystem. We collected presence records of the distribution of dominant GZ species (2 scyphozoans, 2 hydrozoans, 2 ctenophores, and 2 larvaceans) throughout the Arctic Ocean and adjacent marginal seas using existing scientific literature and public databases. We used this information to build three-dimensional species distribution models to understand the current distribution of species and their realized niches. These models, combined with climate change scenarios, allowed us to project future range shifts, and identify potential climate-change winners and losers. Our projections show that as temperatures continue to rise, several boreal species, such as Cyanea capillata and Periphylla periphylla, will expand their range further north. We discuss the consequences of these projected shifts in the context of the GZ species’ roles in the food web, interactions with fish stocks and the biological carbon pump.
06:30 PM
CANDIDATE FOSSIL MEDUSAE FROM EOCENE FLYSH (ADRIA FORELAND, SLOVENIA) (5346)
Primary Presenter: Alenka Malej, NIB PIRAN (alenka.malej@nib.si)
Medusae are widespread and form blooms in many contemporary marine environments. Despite their presumed abundance in ancient oceans, their fossil record is comparatively rare. A review paper (Young & Hagadorn, 2020) listed only 13 confirmed deposits of fossil medusae associated with specific paleoenvironmental settings. Although most medusa fossils have been preserved in paleoenvironments such as shallow sandy shores, estuaries, and lagoons, they may also be fossilised in deeper muddy environments. The material we studied consists of specimens preserved in the Eocene flysch of the Adriatic foreland near the Dinaric trust front. The fossil medusae in question were discovered in a quarry on the Slovenian coast. The putative medusa moulds occur on the lower bedding plane of the medium-grained sandstone, that was formed by an hyperpicnal flow. They exhibit positive relief, are circular to ellipsoidal, and vary in size from 6.5 to 24.5 cm. Most specimens stand in isolation, but some partially overlap. The morphology of these fossils is consistent with that of cnidarian medusae and appear to be analogues of extant scyphozoan Discomedusae. Fossilisation may have occurred after the sinking of the decaying medusa bloom, followed by possible further benthic downward transport leading to the accumulation of medusa carcasses in deep water. Indeed, recent observations indicate that several extant Discomedusae sink rapidly after the collapse of a bloom and accumulate on the seafloor (jelly-biomass deposits), where they are exposed to further processes.
06:30 PM
Modeling the dispersal of Pelagia noctiluca jellyfish in the Mediterranean Sea (5356)
Primary Presenter: Martin Vodopivec, National Institute of Biology (martin.vodopivec@nib.si)
The mauve stinger Pelagia noctiluca is a holoplanktonic oceanic jellyfish that is known for its major outbreaks at irregular intervals. In the northern Adriatic, large blooms have occurred sporadically in recent decades. However, they are sighted more frequently in some other Mediterranean regions. We investigate the dispersal of Pelagia noctiluca in the Adriatic and Mediterranean Seas using an individual-based model (IBM) based on the OpenDrift Lagrangian particle tracking tool. The model accounts for vertical migrations and was run backward in time to explain sightings of Pelagia noctiluca in the Northern Adriatic. The modeling period spans from 1987-2020, and the currents used to drive the particles were obtained from the Copernicus Med MFC physical reanalysis. There is only partial agreement with observations, which is likely due to oversimplification of the model, but may also be, to some extent, due to the lack of regular monitoring campaigns. We also present preliminary results of additional experiments in which the behavior of particles (superindividuals) is modulated by temperature and food availability.
06:30 PM
Assessment of upside-down jellyfish populations (Genus Cassiopea) as potential bioindicators of human development in coastal ecosystems in Jobos Bay National Estuarine Research Reserve (5535)
Primary Presenter: Natalia Lopez-Figueroa, University of South Florida (natalia28@usf.edu)
Bioindicators are used to detect environmental changes and provide quantifiable metrics of the health of ecosystems. Recent work with scyphozoans of the genus Cassiopea has revealed their potential as bioindicators in tropical coastal ecosystems, responding to disturbance of sediments and to pollutants. The ecosystems of Jobos Bay NERR (JBNERR), Puerto Rico are under constant threat of degradation by anthropogenic activity, sea-level rise and associated hydrological changes. Because migration of these ecosystems is limited by coastal development, implementing effective management-action plans are essential. The focus of this project is to assess the potential of Cassiopea as bioindicators of nutrient pollution and other anthropogenic disturbances in coastal ecosystems. Research goals include to: (1) assess distributions of Cassiopea in the shallow subtidal zone adjacent to JBENRR; (2) determine the physico-chemical conditions that influence their blooms across the reserve; and (3) develop and implement a long-term monitoring strategy for Cassiopea populations in coastal waters of Puerto Rico. Nine sites have been established in areas of Jobos Bay, three each as high, mild, and low human impact. Each site includes five transects within a 10 x 25 m plot. Videographic surveys are performed two ways: (1) a total recording of each transects and (2) recording 0.25 m2 quadrats every 2 m along the 10 m transect for percentage coverage. Random quadrat tosses are also performed within the plot and other monitoring sites to compare methods and determine which provides a better estimate of the population structure. Preliminary data show that Cassiopea populations respond to extreme climatic events such as the passing of Hurricane Fiona when populations migrated from near creek outlets to 3.2 km offshore. This project will further characterize these readily observed organisms as low-cost bioindicators to provide rapid environmental assessment to inform mitigation and restoration practices. We aim to promote communication and collaboration among local agencies, institutions, and organizations with the long-term goal of establishing the first jellyfish biomonitoring program in Puerto Rico and perhaps the Caribbean.
06:30 PM
BluebottleWatch: towards the understanding of bluebottles’ dynamics, deploying 3D-printed models in wave/current/wind flumes. (5770)
Primary Presenter: Anne Molcard, MIO University of Toulon (anne.molcard@mio.osupytheas.fr)
Little is known about Physalia physalis, the bluebottle (BB) in Australia, despite the fact that it is responsible for thousands of stings amongst swimmers every year. In particular, its source, distribution and what causes massive stranding events is unclear. BluebottleWatch is an innovative project between universities and Surf Lifesaving Australia that will shed new light on BB dynamics, pathways, and distribution. In addition to in-situ observations and modelling activities, the project includes laboratory experiments in wave flume and wind/current tank to determine the sensitivity of the trajectories of BBs, in terms of their speed, drifting angle and beaching events in response to winds, waves, and currents. The BBs cannot actively swim, so they are passively advected by the external forcings. Realistic 3D printed plastic models based on scans of stranded BBs are used to test different shapes (left or right-handed, variable sail and body size) and weather and ocean conditions. The objective is to establish empirical relationships between the trajectory of the BBs and the intensity of the wind, current and waves for different morphologies, in order to eventually confirm the theoretical results and explain the variability of observed beachings and fill the knowledge gap on the BBs dynamics.
06:30 PM
EFFECT OF OXYGEN CONCENTRATION ON THE CLEARANCE RATE OF SARSIA TUBULOSA (CNIDARIA, HYDROZOA) AND AURELIA AURITA (CNIDARIA, SCYPHOZOA) EPHYRAE AND MEDUSAE (5881)
Primary Presenter: Marie Meffre, MARBEC, University of Montpellier (marie.meffre@gmail.com)
Low oxygen conditions caused by climate change and eutrophication, are expected to shift the distribution of species that are sensitive to hypoxia. Hypoxia sensitivity varies strongly between species and in general, jellyfish are regarded to be more tolerant to low oxygen conditions compared to fish. Zooplanktivorous fish compete with jellyfish for trophic resources, therefore, oxygen could lead to a competitive advantage of jellyfish over fish. In this study, we combine a literature review about the hypoxia tolerance of different zooplanktivorous fish species, with laboratory experiments to assess the effect of low oxygen conditions on jellyfish feeding rates. We used the jellyfish Sarsia tubulosa (Hydrozoa) and Aurelia aurita (Scyphozoa) and tested feeding rates in relation to high (7 mgO2L-1), intermediate (5 mgO2L-1), and low (2 mgO2L-1) oxygen levels. Our results show no significant effect of oxygen concentration on feeding rates for neither S. tubulosa nor A. aurita ephyra or medusa life stages. Our results indicate that the tested jellyfish species and life stages have a potential competitive advantage over certain fish species at low oxygen levels. Thus, ongoing de-oxygenation in coastal areas could favor jellyfish over fish under climate change.
06:30 PM
MONITORING THE BIOGEOGRAPHIC AND PHENOLOGICAL PATTERNS OF JELLYFISH ALONG THE SPANISH COAST THROUGH CITIZEN SCIENCE (6547)
Primary Presenter: John Dobson, University of Alicante (johnyanezdob@gmail.com)
With increasing human activity in the marine environment, encounters with jellyfish are expected to become more frequent. Despite their potential harm to human health and the economy, there is a lack of knowledge regarding their population dynamics. In an effort to better understand their biogeographical patterns and minimize their impact, we have developed MedusApp - a citizen science tool designed for collecting data on jellyfish sightings in the Spanish Mediterranean. During the period spanning from 2018 to 2021, <em>Pelagia noctiluca</em>, <em>Rhizostoma pulmo</em>, <em>Cotylorhiza tuberculata</em>, and <em>Rhizostoma luteum</em> were the most frequently observed jellyfish species. While sightings of all four species increased during this time, from 62,828 to 85,600 sightings, the Jellyfish Intensity (JI) index did not show a significant overall rise in their abundance. Additionally, the seasonality of these species remained consistent, offering a foundation for the development of efficient management strategies over time. Furthermore, new evidence has emerged that <em>R. luteum</em> is extending its range northward in the Western Mediterranean up to the Balearic islands, and becoming a commonly observed species on the Spanish coastline. The data obtained from MedusApp can be utilized to enhance jellyfish management measures, like monitoring, control, and alert systems, with the goal of minimizing jellyfish conflicts with humans and the environment.
06:30 PM
Impact of Ocean Warming and Ocean Acidification on Asexual Reproduction of two scyphozoans of the genus <em>Rhizostoma</em>: <em>R. pulmo </em> and <em>R. luteum</em> (6639)
Primary Presenter: L Prieto, CSIC (laura.prieto@icman.csic.es)
Ocean acidification and warming are challenging marine organisms and ecosystems around the world. The synergetic effects of these two climate change drivers on jellyfish remain still understudied.Here, we examine the independent and combined effects of these two environmental variables on polyp population dynamics of the scyphozoans <em>Rhizostoma pulmo</em>and <em>Rhizostoma luteum</em>. An experiment was conducted to examine asexual reproduction by podocysts formation and strobilation considering current and ca. 2100 winter (Trial 1, 32 days) and summer (Trial 2, 32 days) conditions under a future scenario of “high CO<sub>2>/sub>emissions”. Trial 1 considered a temperature of 18ºC and two pH levels (ambient: 8.0 and 7.7). In Trial 2, two temperatures of 24 and 30ºC were tested in combination with ambient and acidified pH conditions (8.0 and 7.7, respectively). Our results show that <em>R. pulmo</em>scyphistomae would thrive under the future worst scenario predicted for the Mediterranean Sea, their polyp populations will increase with warming temperatures and will undergo proper strobilation by producing healthy ephyrae. In contrast, the survival of <em>R. luteum</em> scyphistomae will be probably compromised under the more pessimistic future predictions as the capacity of this species to undergo strobilation will cease if temperatures reach 30ºC, thereby affecting medusae recruitment and population dynamics.
06:30 PM
ONTOGENIC SWIMMING SPEED OF CARYBDEA MARSUPIALIS (CUBOZOA): IMPLICATIONS FOR SPATIAL DISTRIBUTION (6811)
Primary Presenter: Eva Fonfria, University of Alicante (eva.fonfria@ua.es)
Carybdea marsupialis has been abundantly detected in some shallow waters in the Spanish Mediterranean. However, in a well-studied population off Dénia the distribution of adults, present in areas of high productivity, does not coincide with the location of juveniles, much more dispersed. The aim of this study was to elucidate the influence of the active swimming ability of C. marsupalis on this spatial distribution by measuring its swimming speed in the laboratory and comparing it with local currents obtained from drifting buoys. The swimming speed of 27 specimens, ranging in size from 1.1 to 36 mm diagonal bell width (DBW), was analyzed in aquaria using video cameras and the video analysis tool Tracker. Small juveniles (DBW<5 mm), medium juveniles (5 mm<DBW<15 mm) and adults (DBW>15 mm) showed a mean swimming speed of 9.65±0.76 mm/s, 21.91±2.29 mm/s and 43.10±1.78 mm/s (mean±SE), respectively, following a linear regression with R2=0.92.Comparing these results with the currents obtained, only adults would be able to swim strongly enough to overcome almost 70% of the currents closer to shore, while small juveniles would not reach 17%, allowing habitat selection by the former and leaving the latter dependent on advection. Although complementary experiments (e.g. adding currents) would be necessary to corroborate this, such information would be useful to feed predictive models of jellyfish distribution and to know in advance their presence since, despite the sting of C. marsupalis not being fatal, severe systemic effects have been described in sensitive patients.
SS056P Jellyfish in the Changing Ocean
Description
Time: 6:30 PM
Date: 7/6/2023
Room: Mezzanine