Positive feedback of marine N2O emissions during past extreme warming

Positive feedback of marine N2O emissions during past extreme warming | 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 Physical Sciences - Article Positive feedback of marine N 2 O emissions during past extreme warming Xiaoxiao Zhao, Fanny Monteiro, Kevin Becker, Lukas Dirksen, Julia Cordes, and 15 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8636592/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 The Paleocene–Eocene Thermal Maximum (PETM; 55.9 million years ago) was a rapid, CO2-driven climate polycrisis, with global warming of 5-6°C1,2, ocean acidification3-5, and deoxygenation6-8. These stresses may have affected marine nitrogen cycling, particularly nitrification—a major source of nitrous oxide (N2O) 9 that remains underexplored on geological timescales. By integrating proxy records with Earth System modeling, we show that nitrification globally increased by ~56% during the PETM. Inhibiting effects of ocean deoxygenation10 and acidification11 on nitrification were outweighed by increased ammonium supply and nitrifier niche expansion. Enhanced nitrification led to a ~290% increase in total marine N2O production, contributing 0.3-1.4℃ of warming during the PETM. Our results highlight a strong, positive climatic feedback from nitrogen cycle perturbations under extreme global warming, ocean deoxygenation and acidification. Earth and environmental sciences/Climate sciences/Palaeoceanography Earth and environmental sciences/Biogeochemistry/Element cycles Full Text Additional Declarations There is NO Competing Interest. Supplementary Files SupplementaryMaterialsfor.docx Supplementary information and figures for Positive feedback of marine N2O emissions during past extreme warming 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-8636592","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Physical Sciences - Article","associatedPublications":[],"authors":[{"id":588462160,"identity":"952fc937-7329-47d4-b172-b11ca1ac7ffc","order_by":0,"name":"Xiaoxiao 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