{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,2]],"date-time":"2026-09-02T06:00:08Z","timestamp":1788328808141,"version":"build-2803163510"},"reference-count":40,"publisher":"Oxford University Press (OUP)","issue":"3","license":[{"start":{"date-parts":[[2026,5,29]],"date-time":"2026-05-29T00:00:00Z","timestamp":1780012800000},"content-version":"vor","delay-in-days":52,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2026,4,7]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:p>Aquatic protist quantification underpins our understanding of microbial food webs, biogeochemical cycling and ecosystem functioning. Yet, most estimates of abundance, biomass, size structure and community composition still rely on preserved samples, even though fixation alters the organisms it is meant to preserve. Here, I synthesize experimental, methodological and comparative studies spanning several decades to show that fixation is not neutral, but a systematic, taxon-dependent source of distortion. Across common fixatives, including Lugol\u2019s iodine, formaldehyde, protargol and glutaraldehyde, cell volume may shrink by &amp;gt;80% or swell by 30\u201355%, depending on taxon and protocol. Abundance estimates are likewise biased: aldehyde-preserved samples often yield ciliate counts 10\u201350% lower than Lugol-preserved samples, with even greater losses in fragile naked taxa, while some flagellate staining workflows recover only 20\u201330% of live abundance. These effects are further modified by storage time, handling and analytical method, generating error cascades that affect biomass estimates, trophic interpretation and carbon flux calculations. Because these artifacts vary across taxa and workflows, universal correction factors are not appropriate. Instead, fixation acts as a selective ecological filter, reshaping plankton communities before observation.<\/jats:p>","DOI":"10.1093\/plankt\/fbag038","type":"journal-article","created":{"date-parts":[[2026,5,8]],"date-time":"2026-05-08T11:44:13Z","timestamp":1778240653000},"source":"Crossref","is-referenced-by-count":1,"title":["Preservation-induced distortions in aquatic protists: mechanistic biases, quantitative uncertainties and ecological consequences"],"prefix":"10.1093","volume":"48","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-1069-212X","authenticated-orcid":false,"given":"Albert","family":"Calbet","sequence":"first","affiliation":[{"name":"Institut de Ci\u00e8ncies del Mar, CSIC (Consejo Superior de Investigaciones Cient\u00edficas), Department of Marine Biology and Oceanography, Passeig Mar\u00edtim de la Barceloneta 37-49 , 08003, Barcelona ,","place":["Spain"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"286","published-online":{"date-parts":[[2026,5,29]]},"reference":[{"key":"2026052912225871400_ref1","doi-asserted-by":"publisher","first-page":"257","DOI":"10.3354\/meps010257","article-title":"The ecological role of water-column microbes in the sea","volume":"10","author":"Azam","year":"1983","journal-title":"Mar. Ecol. Prog. Ser."},{"key":"2026052912225871400_ref2","doi-asserted-by":"publisher","first-page":"1266","DOI":"10.1128\/aem.52.6.1266-1272.1986","article-title":"Fixation, counting, and manipulation of heterotrophic nanoflagellates","volume":"52","author":"Bloem","year":"1986","journal-title":"Appl. Environ. Microbiol."},{"key":"2026052912225871400_ref3","doi-asserted-by":"publisher","first-page":"65","DOI":"10.3354\/ame035065","article-title":"Trophic impact and prey selection by crustacean zooplankton on the microbial communities of an oligotrophic coastal area (NW Mediterranean Sea)","volume":"35","author":"Broglio","year":"2004","journal-title":"Aquat. Microb. Ecol."},{"key":"2026052912225871400_ref4","doi-asserted-by":"publisher","first-page":"51","DOI":"10.4319\/lo.2004.49.1.0051","article-title":"Phytoplankton growth, microzooplankton grazing, and carbon cycling in marine systems","volume":"49","author":"Calbet","year":"2004","journal-title":"Limnol. Oceanogr."},{"key":"2026052912225871400_ref5","doi-asserted-by":"publisher","first-page":"11","DOI":"10.3354\/meps09343","article-title":"Phytoplankton growth and microzooplankton grazing along a sub-Arctic fjord (Godth\u00e5bsfjord, West Greenland)","volume":"442","author":"Calbet","year":"2011","journal-title":"Mar. Ecol. Prog. Ser."},{"key":"2026052912225871400_ref6","doi-asserted-by":"publisher","first-page":"517","DOI":"10.1127\/archiv-hydrobiol\/155\/2002\/517","article-title":"Effects of commonly used fixatives on size parameters of freshwater planktonic protists","volume":"155","author":"Chaput","year":"2002","journal-title":"Arch. Hydrobiol."},{"key":"2026052912225871400_ref7","doi-asserted-by":"publisher","first-page":"1761","DOI":"10.1128\/aem.55.7.1761-1765.1989","article-title":"Effects of fixation on cell volume of marine planktonic protozoa","volume":"55","author":"Choi","year":"1989","journal-title":"Appl. Environ. Microbiol."},{"key":"2026052912225871400_ref9","doi-asserted-by":"publisher","first-page":"1","DOI":"10.5194\/os-1-1-2005","article-title":"The reliability of grazing rate estimates from dilution experiments: have we over-estimated rates of organic carbon consumption by microzooplankton?","volume":"1","author":"Dolan","year":"2005","journal-title":"Ocean Sci."},{"key":"2026052912225871400_ref10","doi-asserted-by":"publisher","first-page":"19","DOI":"10.1146\/annurev.es.19.110188.000315","article-title":"Marine plankton food chains","volume":"19","author":"Fenchel","year":"1988","journal-title":"Annu. Rev. Ecol. Syst."},{"key":"2026052912225871400_ref11","doi-asserted-by":"publisher","first-page":"257","DOI":"10.3354\/meps023257","article-title":"Laboratory culture of marine planktonic oligotrichs (Ciliophora, Oligotrichida)","volume":"23","author":"Gifford","year":"1985","journal-title":"Mar. Ecol. Prog. Ser."},{"key":"2026052912225871400_ref12","doi-asserted-by":"crossref","first-page":"193","DOI":"10.1016\/B978-012327645-2\/50006-2","volume-title":"ICES Zooplankton Methodology Manual","author":"Gifford","year":"2000"},{"key":"2026052912225871400_ref13","first-page":"25","article-title":"Effect of different fixatives and preservatives on phytoplankton counts","volume":"34","author":"H\u00e4llfors","year":"1979","journal-title":"Water Res Inst"},{"key":"2026052912225871400_ref14","doi-asserted-by":"publisher","first-page":"395","DOI":"10.4319\/lo.1994.39.2.0395","article-title":"The size ratio between planktonic predators and their prey","volume":"39","author":"Hansen","year":"1994","journal-title":"Limnol. Oceanogr."},{"key":"2026052912225871400_ref15","first-page":"88","volume-title":"Phytoplankton Manual","author":"Hasle","year":"1978"},{"key":"2026052912225871400_ref16","doi-asserted-by":"publisher","first-page":"75","DOI":"10.3354\/ame01539","article-title":"FlowCAM: sizing cells and understanding the impact of size distributions on biovolume of planktonic community structure","volume":"65","author":"Jakobsen","year":"2011","journal-title":"Aquat. Microb. Ecol."},{"key":"2026052912225871400_ref17","doi-asserted-by":"publisher","first-page":"305","DOI":"10.1080\/00288330.1991.9516483","article-title":"Sampling and preservation methods for the quantitative enumeration of microzooplankton","volume":"25","author":"James","year":"1991","journal-title":"New Zealand J Mar Freshw Res"},{"key":"2026052912225871400_ref18","doi-asserted-by":"publisher","first-page":"8","DOI":"10.1017\/S1551929500057060","article-title":"Formaldehyde, formalin, paraformaldehyde and glutaraldehyde: what they are and what they do","volume":"8","author":"Kiernan","year":"2000","journal-title":"Microscopy Today"},{"key":"2026052912225871400_ref19","doi-asserted-by":"publisher","first-page":"39","DOI":"10.5194\/os-1-39-2005","article-title":"Reality checks on microbial food web interactions in dilution experiments: responses to the comments of Dolan and McKeon","volume":"1","author":"Landry","year":"2005","journal-title":"Ocean Sci."},{"key":"2026052912225871400_ref20","doi-asserted-by":"publisher","first-page":"375","DOI":"10.1093\/plankt\/16.4.375","article-title":"A comparison of fixatives for the estimation of abundance and biovolume of planktonic ciliate populations","volume":"16","author":"Leakey","year":"1994","journal-title":"J. Plankton Res."},{"key":"2026052912225871400_ref21","doi-asserted-by":"publisher","first-page":"e02557","DOI":"10.1128\/spectrum.02557-21","article-title":"Optimization of preservation methods provides insights into photosynthetic picoeukaryotes in lakes","volume":"10","author":"Liu","year":"2022","journal-title":"Microbiol. Spectrum"},{"key":"2026052912225871400_ref22","doi-asserted-by":"publisher","first-page":"569","DOI":"10.4319\/lo.2000.45.3.0569","article-title":"Carbon to volume relationships for dinoflagellates, diatoms, and other protist plankton","volume":"45","author":"Menden-Deuer","year":"2000","journal-title":"Limnol. Oceanogr."},{"key":"2026052912225871400_ref23","doi-asserted-by":"publisher","first-page":"41","DOI":"10.3354\/meps222041","article-title":"Effect of preservation on dinoflagellate and diatom cell volume and consequences for carbon biomass predictions","volume":"222","author":"Menden-Deuer","year":"2001","journal-title":"Mar. Ecol. Prog. 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Biobank."},{"key":"2026052912225871400_ref27","doi-asserted-by":"publisher","first-page":"794","DOI":"10.1093\/plankt\/fbad041","article-title":"Impacts of sample storage time on estimates of phytoplankton abundance: how long is too long?","volume":"45","author":"Nogueira","year":"2023","journal-title":"J. Plankton Res."},{"key":"2026052912225871400_ref28","doi-asserted-by":"publisher","first-page":"95","DOI":"10.3354\/ame018095","article-title":"Comparison of a direct live count and an improved quantitative protargol stain (QPS) in determining abundance and cell volumes of pelagic freshwater protozoa","volume":"18","author":"Pfister","year":"1999","journal-title":"Aquat. Microb. Ecol."},{"key":"2026052912225871400_ref29","doi-asserted-by":"publisher","first-page":"710","DOI":"10.1038\/325710a0","article-title":"High rates of consumption of bacteria by pelagic ciliates","volume":"325","author":"Sherr","year":"1987","journal-title":"Nature"},{"key":"2026052912225871400_ref30","first-page":"207","volume-title":"Handbook of Methods in Aquatic Microbial Ecology","author":"Sherr","year":"1993"},{"key":"2026052912225871400_ref31","doi-asserted-by":"publisher","first-page":"293","DOI":"10.1023\/A:1020591307260","article-title":"Significance of predation by protists in aquatic microbial food webs","volume":"81","author":"Sherr","year":"2002","journal-title":"Antonie Van Leeuwenhoek."},{"key":"2026052912225871400_ref32","doi-asserted-by":"publisher","first-page":"57","DOI":"10.1016\/j.dsr2.2013.03.019","article-title":"Microzooplankton grazing impact in the Bering Sea during spring sea ice conditions","volume":"94","author":"Sherr","year":"2013","journal-title":"Deep-Sea Res II"},{"key":"2026052912225871400_ref33","doi-asserted-by":"publisher","first-page":"109","DOI":"10.1016\/S0003-9365(11)80179-X","article-title":"Effets quantitatifs des fixateurs sur la conservation des cili\u00e9s planctoniques d\u2019eau douce","volume":"140","author":"Sime-Ngando","year":"1991","journal-title":"Arch. Protistenkd."},{"key":"2026052912225871400_ref34","doi-asserted-by":"publisher","first-page":"337","DOI":"10.1127\/archiv-hydrobiol\/149\/2000\/337","article-title":"Comparison of three methods for determining flagellate abundance, cell size, and biovolume in cultures and natural freshwater samples","volume":"149","author":"Sonntag","year":"2000","journal-title":"Arch. Hydrobiol."},{"key":"2026052912225871400_ref35","doi-asserted-by":"publisher","first-page":"293","DOI":"10.3354\/meps110293","article-title":"Preservation of marine planktonic ciliates: losses and cell shrinkage during fixation","volume":"110","author":"Stoecker","year":"1994","journal-title":"Mar. Ecol. Prog. Ser."},{"key":"2026052912225871400_ref36","first-page":"69","volume-title":"Phytoplankton Manual","author":"Throndsen","year":"1978"},{"key":"2026052912225871400_ref37","doi-asserted-by":"publisher","first-page":"1","DOI":"10.1080\/05384680.1958.11904091","article-title":"Zur Vervollkommnung der quantitativen phytoplankton-Methodik","volume":"9","author":"Uterm\u00f6hl","year":"1958","journal-title":"Mitt Int Ver Theor Angew Limnol"},{"key":"2026052912225871400_ref38","doi-asserted-by":"publisher","first-page":"629","DOI":"10.1002\/cyto.990100519","article-title":"A simple method to preserve oceanic phytoplankton for flow cytometric analyses","volume":"10","author":"Vaulot","year":"1989","journal-title":"Cytometry"},{"key":"2026052912225871400_ref39","doi-asserted-by":"publisher","first-page":"1705","DOI":"10.1007\/s10811-015-0704-4","article-title":"Marine phytoplankton preservation with Lugol\u2019s: a comparison of solutions","volume":"28","author":"Williams","year":"2016","journal-title":"J. Appl. Phycol."},{"key":"2026052912225871400_ref40","doi-asserted-by":"publisher","first-page":"858","DOI":"10.1007\/s00343-017-5378-0","article-title":"Effects of Lugol\u2019s iodine solution and formalin on cell volume of three bloom-forming dinoflagellates","volume":"35","author":"Yang","year":"2017","journal-title":"Chin. J. Oceanol. Limnol."},{"key":"2026052912225871400_ref41","doi-asserted-by":"publisher","first-page":"1297","DOI":"10.1093\/plankt\/fbn084","article-title":"Effects of Lugol\u2019s fixation on the size structure of natural nano-microplankton samples, analysed by means of an automatic counting method","volume":"30","author":"Zarauz","year":"2008","journal-title":"J. Plankton Res."}],"container-title":["Journal of Plankton Research"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/academic.oup.com\/plankt\/article-pdf\/48\/3\/fbag038\/68432632\/fbag038.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"syndication"},{"URL":"https:\/\/academic.oup.com\/plankt\/article-pdf\/48\/3\/fbag038\/68432632\/fbag038.pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,5,29]],"date-time":"2026-05-29T16:23:03Z","timestamp":1780071783000},"score":1,"resource":{"primary":{"URL":"https:\/\/academic.oup.com\/plankt\/article\/doi\/10.1093\/plankt\/fbag038\/8698120"}},"subtitle":[],"editor":[{"given":"Beatrix E","family":"Beisner","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"editor"}]}],"short-title":[],"issued":{"date-parts":[[2026,4,7]]},"references-count":40,"journal-issue":{"issue":"3","published-print":{"date-parts":[[2026,4,7]]}},"URL":"https:\/\/doi.org\/10.1093\/plankt\/fbag038","relation":{},"ISSN":["0142-7873","1464-3774"],"issn-type":[{"value":"0142-7873","type":"print"},{"value":"1464-3774","type":"electronic"}],"subject":[],"published-other":{"date-parts":[[2026,5]]},"published":{"date-parts":[[2026,4,7]]},"article-number":"fbag038"}}