Transcriptome-resolved diel metabolism of a coastal Phaeocystis bloom links cellular physiology to carbon cycling

Transcriptome-resolved diel metabolism of a coastal Phaeocystis bloom links cellular physiology to carbon cycling | 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 Transcriptome-resolved diel metabolism of a coastal Phaeocystis bloom links cellular physiology to carbon cycling Michiel Perneel*, Jens H. Dujardin*, Nerissa L. Fisher, Rune Lagaisse, and 8 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6767494/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 Planktonic photoautotrophs drive the oceanic carbon cycle by fixing atmospheric CO₂ into organic matter, thereby regulating planetary biogeochemical fluxes. Yet, how the temporal dynamics of phytoplankton metabolism scale to ecosystem-level processes remains poorly resolved, particularly in dynamic coastal environments. In such systems, the haptophyte Phaeocystis globosa regularly forms extensive blooms, producing polysaccharide-rich gels that support colony formation and modulate carbon, nutrient, and oxygen fluxes. These blooms thus offer a natural laboratory to investigate the physiological underpinnings of coastal biogeochemistry. Here, we combine hourly metatranscriptomic profiling with photophysiological and carbonate chemistry measurements during an active P. globosa bloom in the southern North Sea. We identify diel transcriptional oscillations in metabolic pathways, with daytime gene expression enriched in photosynthesis and glycosaminoglycan biosynthesis and export, and nighttime expression linked to growth, replication, nutrient uptake, and stress response. By correlating gene expression with in situ carbon drawdown and oxygen production, we identify candidate molecular markers of primary production, including key enzymes in light harvesting and polysaccharide synthesis. Our findings demonstrate how transcriptome-resolved diel dynamics of bloom-forming phytoplankton can reveal mechanistic links between cellular physiology and ecosystem-scale carbon cycling, providing a framework to enhance molecular monitoring of coastal ocean function. *Michiel Perneel and Jens H. Dujardin contributed equally to this work. Biological sciences/Ecology/Biooceanography/Microbial biooceanography Biological sciences/Molecular biology/Transcriptomics Earth and environmental sciences/Biogeochemistry/Carbon cycle Phaeocystis blooms Carbon Cycle Diel dynamics Metatranscriptomics Marine Gels Full Text Additional Declarations There is NO Competing Interest. Supplementary Files supplementarydataset1.xlsx Supplementary Dataset 1 supplementarydataset2.xlsx Supplementary Dataset 2 SupplementaryInformation.docx Supplementary Information 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. 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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-6767494","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":464315118,"identity":"a871145c-49a1-4ba8-9707-246cbb2f8267","order_by":0,"name":"Michiel Perneel*","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA/UlEQVRIie3PMUvEMBTA8fcIvC4V11cK5ycQegjXOzj8LClCb7r9BodIIbdUXPVb3HjjQaAuBVc3C0Lnurl4GoeCDm1WwfwJJA/yIwTA5/uLCSCQMO/H+QQCVGCXi3A/8gUIFwFL4AfJlLDbGDnfirZpNgxpcNs23YZXOyOKDvfLQTIzlCayZliUj+n0vub1zqBKsM5HSEicaYbkOaf4RPP6oUAlURsHOVry0lL8ceRVZMkB9aeDqO9XiGJULE8F3ijUh7G/zFhWHC7KnKKy4umdwAKy+mqYPJk2er9eTtKgIraHMwq2r93b/nKQ9IXJr1E6gS1xX/H5fL7/2hftMEmM5MDs5wAAAABJRU5ErkJggg==","orcid":"","institution":"Flanders Marine Institute (VLIZ), 8400 Oostende, Belgium; Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium; Center for Plant Systems Biology, VIB, Ghent, Belgium","correspondingAuthor":true,"prefix":"","firstName":"Michiel","middleName":"","lastName":"Perneel*","suffix":""},{"id":464315119,"identity":"b8dda320-6694-44d2-81f2-45bc9bd5247e","order_by":1,"name":"Jens H. 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