Interactive effects of CO2 concentration and temperature on photosynthesis and growth of cultivated Ulva prolifera germling clusters

Interactive effects of CO2 concentration and temperature on photosynthesis and growth of cultivated Ulva prolifera germling clusters | 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 Research Article Interactive effects of CO2 concentration and temperature on photosynthesis and growth of cultivated Ulva prolifera germling clusters Kaho Yamaha, Gregory N. Nishihara, Yoichi Sato, Eri Inomata This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6725046/v2 This work is licensed under a CC BY 4.0 License Status: Under Review Version 2 posted 5 You are reading this latest preprint version Show more versions Abstract Terrestrial aquaculture of the economically important green seaweed Ulva prolifera offers potential for stable production but requires optimization due to high operational costs. While CO2 enrichment can enhance growth, its interaction with temperature is not fully quantified for the germling cluster cultivation method. The interactive effects of dissolved CO2 concentration (0.07 to 12 µatm) and temperature (10, 20, and 30 °C) on the net photosynthetic rate (NPR) and relative growth rate (RGR) of cultivated U. prolifera germling clusters under controlled laboratory conditions (150 to 200 µmol photons m-2 s-1) were investigated. NPR was measured via oxygen evolution in short-term incubations, and RGR was determined from wet weight changes over 6-day batch cultures with daily medium exchange. A generalized additive model was used in the analysis. RGR peaked under different CO2 concentrations that varied with temperature, reaching a maximum value of 0.40 at 0.40 µatm for the 10 °C treatment, 0.69 at 1.41 µatm for the 20 °C treatment, and 0.67 at 1.77 µatm for the 30 °C treatment. In contrast, NPR showed complex responses, generally reaching a plateau above 5 µatm at 10 °C and 20 °C, but remaining relatively high across all CO2 levels at 30 °C. The discrepancies observed regarding the response of photosynthesis and growth to CO2 concentrations indicates that factors beyond immediate carbon fixation (e.g., the importance of time-scales) influence overall biomass accumulation under varying CO2 (i.e., pH) conditions. CO2 enrichment Temperature Terrestrial aquaculture Relative growth rate Photosynthesis Carbon concentrating mechanism Full Text Additional Declarations No competing interests reported. Cite Share Download PDF Status: Under Review Version 2 posted Reviews received at journal 10 Sep, 2025 Reviewers agreed at journal 10 Sep, 2025 Reviewers invited by journal 10 Sep, 2025 Submission checks completed at journal 10 Sep, 2025 First submitted to journal 02 Sep, 2025 You are reading this latest preprint version Show more versions 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. 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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-6725046","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":513360658,"identity":"a54c07e9-7e3c-4e55-a16a-d6b9aa52862f","order_by":0,"name":"Kaho Yamaha","email":"","orcid":"","institution":"Nagasaki University","correspondingAuthor":false,"prefix":"","firstName":"Kaho","middleName":"","lastName":"Yamaha","suffix":""},{"id":513360660,"identity":"e05e7553-f053-450c-9fce-41fd93ed2ebd","order_by":1,"name":"Gregory N. 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