{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,30]],"date-time":"2026-09-30T18:19:31Z","timestamp":1790792371970,"version":"4.1.0"},"reference-count":31,"publisher":"MDPI AG","issue":"9","license":[{"start":{"date-parts":[[2021,8,26]],"date-time":"2021-08-26T00:00:00Z","timestamp":1629936000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["JoF"],"abstract":"<jats:p>Ergosterol has traditionally been used as a proxy to estimate fungal biomass as it is almost exclusively found in fungal lipid membranes. Ergosterol determination has been mostly used for fungal samples from terrestrial, freshwater, salt marsh- and mangrove-dominated environments or to describe fungal degradation of plant matter. In the open ocean, however, the expected concentrations of ergosterol are orders of magnitude lower than in terrestrial or macrophyte-dominated coastal systems. Consequently, the fungal biomass in the open ocean remains largely unknown. Recent evidence based on microscopy and -omics techniques suggests, however, that fungi contribute substantially to the microbial biomass in the oceanic water column, highlighting the need to accurately determine fungal biomass in the open ocean. We performed ergosterol extractions of an oceanic fungal isolate (Rhodotorula sphaerocarpa) with biomass concentrations varying over nine orders of magnitude. While after the initial chloroform-methanol extraction ~87% of the ergosterol was recovered, a second extraction recovered an additional ~10%. Testing this extraction method on samples collected from the open Atlantic Ocean, we successfully determined ergosterol concentrations as low as 0.12 pM. Thus, this highly sensitive method is well suited for measuring fungal biomass from open ocean waters, including deep-sea environments.<\/jats:p>","DOI":"10.3390\/jof7090690","type":"journal-article","created":{"date-parts":[[2021,8,26]],"date-time":"2021-08-26T05:41:50Z","timestamp":1629956510000},"page":"690","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":24,"title":["Adapting an Ergosterol Extraction Method with Marine Yeasts for the Quantification of Oceanic Fungal Biomass"],"prefix":"10.3390","volume":"7","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-0088-4489","authenticated-orcid":false,"given":"Katherine","family":"Salazar Alekseyeva","sequence":"first","affiliation":[{"name":"Department of Functional and Evolutionary Ecology, Microbial Oceanography Working Group, University of Vienna, 1030 Vienna, Austria"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Barbara","family":"M\u00e4hnert","sequence":"additional","affiliation":[{"name":"Department of Functional and Evolutionary Ecology, Microbial Oceanography Working Group, University of Vienna, 1030 Vienna, Austria"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5883-2879","authenticated-orcid":false,"given":"Franz","family":"Berthiller","sequence":"additional","affiliation":[{"name":"Department of Agrobiotechnology (IFA-Tulln), University of Natural Resources and Life Sciences, Vienna (BOKU), 3430 Tulln, Austria"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Eva","family":"Breyer","sequence":"additional","affiliation":[{"name":"Department of Functional and Evolutionary Ecology, Microbial Oceanography Working Group, University of Vienna, 1030 Vienna, Austria"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Gerhard J.","family":"Herndl","sequence":"additional","affiliation":[{"name":"Department of Functional and Evolutionary Ecology, Microbial Oceanography Working Group, University of Vienna, 1030 Vienna, Austria"},{"name":"Department of Marine Microbiology and Biogeochemistry, Royal Netherlands Institute for Sea Research (NIOZ), University of Utrecht, 1790 AB Den Burg, Texel, The Netherlands"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8907-1494","authenticated-orcid":false,"given":"Federico","family":"Baltar","sequence":"additional","affiliation":[{"name":"Department of Functional and Evolutionary Ecology, Microbial Oceanography Working Group, University of Vienna, 1030 Vienna, Austria"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2021,8,26]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"815","DOI":"10.1016\/j.dsr2.2008.10.040","article-title":"Distribution and abundance of marine microbes in the Southern Ocean between 30 and 80 E","volume":"57","author":"Thomson","year":"2010","journal-title":"Deep Sea Res. 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