{"paper_id":"5607df7f-d9a7-4d22-985a-03879dec72c2","body_text":"The emergence of top-down controls on marine biomass in the 21st Century | 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Article The emergence of top-down controls on marine biomass in the 21 st Century Tyler Rohr This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8894424/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted You are reading this latest preprint version Abstract Uncertainty in the fate of marine phytoplankton biomass in a warming ocean has typically been attributed to uncertainty in how more light but less nutrients will impact growth conditions. However, across 11 CMIP6 models forced with high emissions, 50% of ensemble biomass moves in the opposite direction of cell-division rates. This indicates that regardless of the balance of bottom-up controls, biomass change is often determined by top-down driven changes to loss processes. Importantly, when biomass is modified from the top-down, a large fraction becomes decoupled from changes in primary (62%), secondary (65%) and export (46%) production, carrying critical implications for how to interpret satellite-based NPP trends, force fisheries models and predict ocean-climate feedbacks. We diagnostically decompose the drivers of all loss terms and find that the vertical redistribution of biomass is the largest driver of top-down control, but that at least 4 distinct pathways can decouple biomass from growth conditions. Earth and environmental sciences/Ocean sciences/Marine chemistry Earth and environmental sciences/Climate sciences/Biogeochemistry Full Text Additional Declarations There is NO Competing Interest. Supplementary Files SupplementaryMaterialRohr.pdf Supplementary information updated Cite Share Download PDF Status: Under Review 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-8894424\",\"acceptedTermsAndConditions\":true,\"allowDirectSubmit\":false,\"archivedVersions\":[],\"articleType\":\"Article\",\"associatedPublications\":[],\"authors\":[{\"id\":616619802,\"identity\":\"0ad4430b-125f-4674-951f-93499efadb4e\",\"order_by\":0,\"name\":\"Tyler Rohr\",\"email\":\"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA8ElEQVRIiWNgGAWjYFAC5gYwZcDAfAAqkoBfAw8DI0wLWwLDARK18BgQp8VeIrHxcQXDPTlz6TPfpD/U1DHws+cYMPxsw2OLRGKz4RmGYmPLvtxtEgeOHWaQ7HljwNiLX0ubZANDQuKGM7xALWwHGAxuAG3hxa+l/SdEC88ziQP/6hjsgVoY/xKwhRGqhU3iYBszg4FEjgEzXlvOPGyWbDBIMDY4w2ZscbbvMI/EmWcFh2XO4dbC3p588GNDRYKcwRnmhzcqvtXJ8bcnb3z4pgy3FgaBBAZQpCCsBREH8GhgYODHLz0KRsEoGAWjgIEBAAkmTmCGfrIPAAAAAElFTkSuQmCC\",\"orcid\":\"https://orcid.org/0000-0001-6599-8068\",\"institution\":\"Institute for Marine and Antarctic Studies at the University of Tasmania\",\"correspondingAuthor\":true,\"prefix\":\"\",\"firstName\":\"Tyler\",\"middleName\":\"\",\"lastName\":\"Rohr\",\"suffix\":\"\"}],\"badges\":[],\"createdAt\":\"2026-02-16 15:36:11\",\"currentVersionCode\":1,\"declarations\":\"\",\"doi\":\"10.21203/rs.3.rs-8894424/v1\",\"doiUrl\":\"https://doi.org/10.21203/rs.3.rs-8894424/v1\",\"draftVersion\":[],\"editorialEvents\":[],\"editorialNote\":\"\",\"failedWorkflow\":false,\"files\":[{\"id\":106095072,\"identity\":\"6ad006b3-d2f0-4904-925b-aa2474241a7f\",\"added_by\":\"auto\",\"created_at\":\"2026-04-03 11:44:09\",\"extension\":\"pdf\",\"order_by\":1,\"title\":\"\",\"display\":\"\",\"copyAsset\":false,\"role\":\"manuscript-pdf\",\"size\":8236175,\"visible\":true,\"origin\":\"\",\"legend\":\"Article File\",\"description\":\"\",\"filename\":\"ManuscriptRohr.pdf\",\"url\":\"https://assets-eu.researchsquare.com/files/rs-8894424/v1_covered_2a374fba-00e2-418d-b137-a49827610ea8.pdf\"},{\"id\":106090148,\"identity\":\"cefccb41-339f-4e24-9fec-88e3d5089fa1\",\"added_by\":\"auto\",\"created_at\":\"2026-04-03 10:42:06\",\"extension\":\"pdf\",\"order_by\":2,\"title\":\"\",\"display\":\"\",\"copyAsset\":false,\"role\":\"supplement\",\"size\":22552030,\"visible\":true,\"origin\":\"\",\"legend\":\"Supplementary information updated\",\"description\":\"\",\"filename\":\"SupplementaryMaterialRohr.pdf\",\"url\":\"https://assets-eu.researchsquare.com/files/rs-8894424/v1/9baf0313b76450c9b55bced0.pdf\"}],\"financialInterests\":\"There is \\u003cb\\u003eNO\\u003c/b\\u003e Competing Interest.\",\"formattedTitle\":\"\\u003cp\\u003eThe emergence of top-down controls on marine biomass in the 21\\u003csup\\u003est\\u003c/sup\\u003e Century\\u003c/p\\u003e\",\"fulltext\":[],\"fulltextSource\":\"\",\"fullText\":\"\",\"funders\":[],\"hasAdminPriorityOnWorkflow\":false,\"hasManuscriptDocX\":false,\"hasOptedInToPreprint\":true,\"hasPassedJournalQc\":\"\",\"hasAnyPriority\":true,\"hideJournal\":false,\"highlight\":\"\",\"institution\":\"\",\"isAcceptedByJournal\":false,\"isAuthorSuppliedPdf\":true,\"isDeskRejected\":\"\",\"isHiddenFromSearch\":false,\"isInQc\":false,\"isInWorkflow\":false,\"isPdf\":true,\"isPdfUpToDate\":true,\"isWithdrawnOrRetracted\":false,\"journal\":{\"display\":true,\"email\":\"info@researchsquare.com\",\"identity\":\"nature-portfolio\",\"isNatureJournal\":true,\"hasQc\":false,\"allowDirectSubmit\":false,\"externalIdentity\":\"\",\"sideBox\":\"\",\"snPcode\":\"\",\"submissionUrl\":\"\",\"title\":\"Nature Portfolio\",\"twitterHandle\":\"\",\"acdcEnabled\":false,\"dfaEnabled\":false,\"editorialSystem\":\"ejp\",\"reportingPortfolio\":\"\",\"inReviewEnabled\":true,\"inReviewRevisionsEnabled\":false},\"keywords\":\"\",\"lastPublishedDoi\":\"10.21203/rs.3.rs-8894424/v1\",\"lastPublishedDoiUrl\":\"https://doi.org/10.21203/rs.3.rs-8894424/v1\",\"license\":{\"name\":\"CC BY 4.0\",\"url\":\"https://creativecommons.org/licenses/by/4.0/\"},\"manuscriptAbstract\":\"Uncertainty in the fate of marine phytoplankton biomass in a warming ocean has typically been attributed to uncertainty in how more light but less nutrients will impact growth conditions. 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