Integrated effects of light intensity, spectral composition and photoperiod fragmentation on duckweed growth and nutrient removal

Integrated effects of light intensity, spectral composition and photoperiod fragmentation on duckweed growth and nutrient removal | 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 Integrated effects of light intensity, spectral composition and photoperiod fragmentation on duckweed growth and nutrient removal Piotr Cichy, Joanna Kalka This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8986426/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 10 You are reading this latest preprint version Abstract Duckweeds are widely used in wastewater treatment and biomass production systems; however, the combined effects of light intensity, spectral composition and photoperiod structure on their performance remain insufficiently understood. This study evaluated how these light parameters influence growth and nutrient removal in three duckweed species ( Lemna minor, Landoltia punctata and Spirodela polyrhiza ) cultivated under controlled conditions. Light intensity (50–1220 µmol m⁻² s⁻¹), spectral composition (blue, green, red, white and mixed spectra), and fragmented photoperiod regimes (12L:12D to 1L:1D) were examined. Spectral and photoperiod treatments were conducted at a constant daily light integral (~ 12.96 mol m⁻² d⁻¹), enabling isolation of light-quality and temporal effects from total photon dose. Relative growth rate (RGR), dry biomass and nitrogen (N–NO₃) and phosphorus (P–PO₄) removal were assessed. Growth responses showed saturation with increasing light intensity, with RGR saturating at lower levels (160–296 µmol m⁻² s⁻¹) than dry biomass (~ 343–440 µmol m⁻² s⁻¹). Red-enriched white light generally enhanced growth and nutrient removal across species, whereas fragmented photoperiods reduced growth despite identical daily light integral. Biological sciences/Ecology Earth and environmental sciences/Ecology Earth and environmental sciences/Environmental sciences Biological sciences/Plant sciences duckweed light intensity light quality intermittent photoperiod plant growth nutrient removal Full Text Additional Declarations No competing interests reported. Supplementary Files SciRepSI.docx Cite Share Download PDF Status: Under Review Version 1 posted Editorial decision: Revision requested 15 Apr, 2026 Reviews received at journal 05 Apr, 2026 Reviews received at journal 30 Mar, 2026 Reviewers agreed at journal 25 Mar, 2026 Reviewers agreed at journal 24 Mar, 2026 Reviewers invited by journal 24 Mar, 2026 Editor invited by journal 03 Mar, 2026 Editor assigned by journal 28 Feb, 2026 Submission checks completed at journal 28 Feb, 2026 First submitted to journal 27 Feb, 2026 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. 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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-8986426","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":612097025,"identity":"a83ee6fc-5f00-4bf3-9c14-fd7dd1ab6245","order_by":0,"name":"Piotr Cichy","email":"","orcid":"","institution":"Silesian University of Technology","correspondingAuthor":false,"prefix":"","firstName":"Piotr","middleName":"","lastName":"Cichy","suffix":""},{"id":612097026,"identity":"35abba5c-1fc0-47b7-9263-3a5ccf463341","order_by":1,"name":"Joanna Kalka","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA+ElEQVRIie3PMWrDMBTG8U8InhaFrgaF+AoyBoeAepdkSZcGOnXqYBBYS9rZU45RsgvcJQfoaCh0DhQCoVDqOl26KB4D1X8Rb/hJekAsdoGx8nRqCAL2wBiiG9tBhBNYDUjwbpwPeK0nXA4h3Nn3t7sH5FeWFh/XWyNTC2pDhK2baV43KBJPXq12S6k9hA6Sel4oSTDwolSrykvNQUmY3ByU/IJJvbCfs478fOwMuS3UqEKhPTWKdQT+HFnv7tXoKckzT8vZY78Lc8FdMueelTyYbPNS5a/HrZmkzjbtPkTK/kh+3+wnVgUAkP795ukCCpJYLBb7d30DjH1B1/Hd+dAAAAAASUVORK5CYII=","orcid":"","institution":"Silesian University of Technology","correspondingAuthor":true,"prefix":"","firstName":"Joanna","middleName":"","lastName":"Kalka","suffix":""}],"badges":[],"createdAt":"2026-02-27 09:54:29","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-8986426/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-8986426/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":105566379,"identity":"ddac0a67-92de-4768-ad6e-085945de4ca2","added_by":"auto","created_at":"2026-03-27 12:56:18","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":2453497,"visible":true,"origin":"","legend":"","description":"","filename":"Scientificreports.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8986426/v1_covered_699331c4-51df-431a-b349-63475694c540.pdf"},{"id":105504634,"identity":"9f18895b-a2e1-4775-825f-e10f7875cefa","added_by":"auto","created_at":"2026-03-26 18:33:18","extension":"docx","order_by":0,"title":"","display":"","copyAsset":false,"role":"supplement","size":319745,"visible":true,"origin":"","legend":"","description":"","filename":"SciRepSI.docx","url":"https://assets-eu.researchsquare.com/files/rs-8986426/v1/e4e688b92a6b1fb565f8a187.docx"}],"financialInterests":"No competing interests reported.","formattedTitle":"Integrated effects of light intensity, spectral composition and photoperiod fragmentation on duckweed growth and nutrient removal","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"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":"[email protected]","identity":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"duckweed, light intensity, light quality, intermittent photoperiod, plant growth, nutrient removal","lastPublishedDoi":"10.21203/rs.3.rs-8986426/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8986426/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eDuckweeds are widely used in wastewater treatment and biomass production systems; however, the combined effects of light intensity, spectral composition and photoperiod structure on their performance remain insufficiently understood. This study evaluated how these light parameters influence growth and nutrient removal in three duckweed species (\u003cem\u003eLemna minor, Landoltia punctata\u003c/em\u003e and \u003cem\u003eSpirodela polyrhiza\u003c/em\u003e) cultivated under controlled conditions. Light intensity (50\u0026ndash;1220 \u0026micro;mol m⁻\u0026sup2; s⁻\u0026sup1;), spectral composition (blue, green, red, white and mixed spectra), and fragmented photoperiod regimes (12L:12D to 1L:1D) were examined. Spectral and photoperiod treatments were conducted at a constant daily light integral (~\u0026thinsp;12.96 mol m⁻\u0026sup2; d⁻\u0026sup1;), enabling isolation of light-quality and temporal effects from total photon dose. Relative growth rate (RGR), dry biomass and nitrogen (N\u0026ndash;NO₃) and phosphorus (P\u0026ndash;PO₄) removal were assessed. Growth responses showed saturation with increasing light intensity, with RGR saturating at lower levels (160\u0026ndash;296 \u0026micro;mol m⁻\u0026sup2; s⁻\u0026sup1;) than dry biomass (~\u0026thinsp;343\u0026ndash;440 \u0026micro;mol m⁻\u0026sup2; s⁻\u0026sup1;). Red-enriched white light generally enhanced growth and nutrient removal across species, whereas fragmented photoperiods reduced growth despite identical daily light integral.\u003c/p\u003e","manuscriptTitle":"Integrated effects of light intensity, spectral composition and photoperiod fragmentation on duckweed growth and nutrient removal","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-03-26 18:33:13","doi":"10.21203/rs.3.rs-8986426/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2026-04-15T08:34:05+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-04-06T00:15:22+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-03-30T09:01:12+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"72474085465265250552188397444965680019","date":"2026-03-25T14:34:46+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"21106617059163434273593106263915313128","date":"2026-03-25T02:35:35+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2026-03-25T00:53:20+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2026-03-03T09:40:44+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2026-02-28T11:22:12+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2026-02-28T11:20:29+00:00","index":"","fulltext":""},{"type":"submitted","content":"Scientific Reports","date":"2026-02-27T09:37:47+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"7b0e26c8-9172-423d-942d-031b92e5c068","owner":[],"postedDate":"March 26th, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[{"id":65129007,"name":"Biological sciences/Ecology"},{"id":65129008,"name":"Earth and environmental sciences/Ecology"},{"id":65129009,"name":"Earth and environmental sciences/Environmental sciences"},{"id":65129010,"name":"Biological sciences/Plant sciences"}],"tags":[],"updatedAt":"2026-05-18T00:38:17+00:00","versionOfRecord":[],"versionCreatedAt":"2026-03-26 18:33:13","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8986426","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8986426","identity":"rs-8986426","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}