Microbial degradation of jellyfish detritus promotes phytoplankton growth in coastal marine ecosystems

Microbial degradation of jellyfish detritus promotes phytoplankton growth in coastal marine ecosystems | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Article Microbial degradation of jellyfish detritus promotes phytoplankton growth in coastal marine ecosystems Tinkara Tinta, Eduard Fadeev, Mauro Celussi, Cecilia Balestra, and 3 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7053203/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Gelatinous zooplankton, hereinafter cnidarian subphylum Medusozoa and phylum Ctenophora or ‘jellyfish’, are widespread in marine ecosystems, and some species can form massive blooms under favorable environmental conditions. As these blooms decay, they release large amounts of labile, protein-rich organic matter (jelly-OM) into the water column, providing readily available substrate for microbial communities. To investigate the microbial response to jelly-OM, we conducted a two-stage microcosm experiment simulating conditions during a bloom of the invasive ctenophore Mnemiopsis leidyi in a coastal pelagic environment. In the first stage of our experiment, jelly-OM stimulated rapid growth of opportunistic bacteria, particularly Pseudoalteromonadaceae , known key degraders of jelly-OM, consistently dominating the microbial communities driving jelly-OM degradation across experiments, regardless of jellyfish species. These bacteria both respired and assimilated jelly-derived carbon. The bacterial degradation of jelly-OM was linked to elevated activities of leucine aminopeptidase, lipase, chitinase, and alkaline phosphatase, leading to substantial ammonium accumulation. Metagenomic analysis revealed enhanced microbial metabolism of amino acids, lipids, and carbohydrates in jelly-OM treatments. Compared to decaying phytoplankton, jelly-OM triggers a distinct microbial response, reflecting its unique biochemical composition and highlighting its potential to alter coastal ecosystem structure and function. In the second stage of our microcosm experiment, a fresh microbial assemblage was exposed to 0.2 µm pre-filtered residues from bacterial jelly-OM degradation. After three days, primary production and phytoplankton biomass increased significantly, reaching levels comparable to seasonal phytoplankton peaks in the region. Growth of phytoplankton community, dominated by diatoms, was likely fueled by accumulated ammonium. Concurrently, the bacterial community shifted towards taxa typically associated with phytoplankton blooms, without significant enrichment in metabolic pathways compared to controls. Our in situ data suggests a potential coupling between jellyfish and phytoplankton via rapid bacterial degradation of jelly-OM. Thus, jellyfish blooms appear to be significant sources of both organic and inorganic nutrients, capable of triggering ecosystem shifts, such as enhanced primary production. As jellyfish are projected to thrive under future ocean conditions, our findings underscore the need to re-evaluate their role in biogeochemical cycles—particularly as overlooked drivers of phytoplankton dynamics. Biological sciences/Ecology/Biooceanography/Microbial biooceanography Biological sciences/Microbiology/Environmental microbiology/Water microbiology Jellyfish blooms Organic matter degradation Microbial remineralization Phytoplankton dynamics Primary production Biogeochemical cycling Microscopy-based approach Metagenomics Full Text Additional Declarations There is NO Competing Interest. Supplementary Files TableS1.pdf Table S1 TableS2.pdf Table S2 TableS3.pdf Table S3 TableS4.pdf Table S4 FigureS1EEA.pdf Supplementary Figure S1 FigureS2metaGtaxonomyinsitu.pdf Supplementary Figure S2 Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-7053203","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":484354799,"identity":"e6cc6a28-640e-4b00-8aa2-9875808fa383","order_by":0,"name":"Tinkara 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ecosystems","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":true,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":true,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Jellyfish blooms, Organic matter degradation, Microbial remineralization, Phytoplankton dynamics, Primary production, Biogeochemical cycling, Microscopy-based approach, Metagenomics","lastPublishedDoi":"10.21203/rs.3.rs-7053203/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7053203/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"Gelatinous zooplankton, hereinafter cnidarian subphylum \u003ci\u003eMedusozoa\u003c/i\u003e and phylum \u003ci\u003eCtenophora\u003c/i\u003e or ‘jellyfish’, are widespread in marine ecosystems, and some species can form massive blooms under favorable environmental conditions. As these blooms decay, they release large amounts of labile, protein-rich organic matter (jelly-OM) into the water column, providing readily available substrate for microbial communities. To investigate the microbial response to jelly-OM, we conducted a two-stage microcosm experiment simulating conditions during a bloom of the invasive ctenophore \u003ci\u003eMnemiopsis leidyi\u003c/i\u003e in a coastal pelagic environment. In the first stage of our experiment, jelly-OM stimulated rapid growth of opportunistic bacteria, particularly \u003ci\u003ePseudoalteromonadaceae\u003c/i\u003e, known key degraders of jelly-OM, consistently dominating the microbial communities driving jelly-OM degradation across experiments, regardless of jellyfish species. These bacteria both respired and assimilated jelly-derived carbon. The bacterial degradation of jelly-OM was linked to elevated activities of leucine aminopeptidase, lipase, chitinase, and alkaline phosphatase, leading to substantial ammonium accumulation. Metagenomic analysis revealed enhanced microbial metabolism of amino acids, lipids, and carbohydrates in jelly-OM treatments. Compared to decaying phytoplankton, jelly-OM triggers a distinct microbial response, reflecting its unique biochemical composition and highlighting its potential to alter coastal ecosystem structure and function. In the second stage of our microcosm experiment, a fresh microbial assemblage was exposed to 0.2 µm pre-filtered residues from bacterial jelly-OM degradation. After three days, primary production and phytoplankton biomass increased significantly, reaching levels comparable to seasonal phytoplankton peaks in the region. Growth of phytoplankton community, dominated by diatoms, was likely fueled by accumulated ammonium. Concurrently, the bacterial community shifted towards taxa typically associated with phytoplankton blooms, without significant enrichment in metabolic pathways compared to controls. Our in situ data suggests a potential coupling between jellyfish and phytoplankton via rapid bacterial degradation of jelly-OM. Thus, jellyfish blooms appear to be significant sources of both organic and inorganic nutrients, capable of triggering ecosystem shifts, such as enhanced primary production. 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