{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,2]],"date-time":"2026-03-02T11:05:58Z","timestamp":1772449558159,"version":"3.50.1"},"reference-count":21,"publisher":"MDPI AG","issue":"3","license":[{"start":{"date-parts":[[2026,3,1]],"date-time":"2026-03-01T00:00:00Z","timestamp":1772323200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100000038","name":"Natural Science and Engineering Research Council of Canada","doi-asserted-by":"publisher","award":["RGPIN 03796"],"award-info":[{"award-number":["RGPIN 03796"]}],"id":[{"id":"10.13039\/501100000038","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100000038","name":"Natural Science and Engineering Research Council of Canada","doi-asserted-by":"publisher","award":["RGPIN 03906"],"award-info":[{"award-number":["RGPIN 03906"]}],"id":[{"id":"10.13039\/501100000038","id-type":"DOI","asserted-by":"publisher"}]},{"name":"Canada Foundation for Innovation and Nova Scotia Research as well as Innovation Trust","award":["31188"],"award-info":[{"award-number":["31188"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Algorithms"],"abstract":"<jats:p>Harmful algal blooms (HABs) remain a growing threat to freshwater systems, yet predictive tools often rely on generic indices centered on chlorophyll-a (Chl-a), which is not cyanobacteria-specific. This paper introduces the Threshold Index (TRINDEX) as a new tool for predicting harmful algal blooms (HABs) in freshwater lakes. Unlike classical indices, TRINDEX explicitly integrates phycocyanin (PC), the pigment unique to cyanobacteria, making it the first cyanobacteria-specific threshold-based index. Using receiver operating characteristic (ROC) curve analysis, TRINDEX demonstrated excellent predictive tool, with area under the curve (AUC) values of 0.956 for TRINDEX2 and 0.888 for TRINDEX1 in Lake Torment, Nova Scotia. Furthermore, cohort studies, adapted from epidemiology, introduced here for the first time in HAB research, further validated TRINDEX, showing a 14.1% predicted bloom risk compared to 17.6% observed risk in Lake Torment. Validation across three independent waterbodies in New Brunswick confirmed TRINDEX\u2019s robustness, with AUC values ranging from 0.714 to 0.979. These innovations demonstrate that TRINDEX yields robust, quantitative bloom thresholds, providing a practical foundation for future early-warning systems linked with remote sensing and real-time sensors to support effective water-quality management.<\/jats:p>","DOI":"10.3390\/a19030184","type":"journal-article","created":{"date-parts":[[2026,3,2]],"date-time":"2026-03-02T10:24:34Z","timestamp":1772447074000},"page":"184","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Bridging Epidemiology and Limnology for Improved Prediction of Harmful Algal Blooms in Freshwater Lakes"],"prefix":"10.3390","volume":"19","author":[{"given":"My Thi","family":"Nguyen","sequence":"first","affiliation":[{"name":"Biofluids and Biosystems Modeling Lab (BBML), Faculty of Agriculture, Dalhousie University, Truro-Bible Hill, NS B2N 5E3, Canada"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Kateryna","family":"Hushchyna","sequence":"additional","affiliation":[{"name":"Biofluids and Biosystems Modeling Lab (BBML), Faculty of Agriculture, Dalhousie University, Truro-Bible Hill, NS B2N 5E3, Canada"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Qianbo","family":"Sheng","sequence":"additional","affiliation":[{"name":"Biofluids and Biosystems Modeling Lab (BBML), Faculty of Agriculture, Dalhousie University, Truro-Bible Hill, NS B2N 5E3, Canada"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Kayla","family":"McLellan","sequence":"additional","affiliation":[{"name":"Biofluids and Biosystems Modeling Lab (BBML), Faculty of Agriculture, Dalhousie University, Truro-Bible Hill, NS B2N 5E3, Canada"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Quoc Bao","family":"Vo","sequence":"additional","affiliation":[{"name":"Biofluids and Biosystems Modeling Lab (BBML), Faculty of Agriculture, Dalhousie University, Truro-Bible Hill, NS B2N 5E3, Canada"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5501-5758","authenticated-orcid":false,"given":"Tri","family":"Nguyen-Quang","sequence":"additional","affiliation":[{"name":"Biofluids and Biosystems Modeling Lab (BBML), Faculty of Agriculture, Dalhousie University, Truro-Bible Hill, NS B2N 5E3, Canada"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2026,3,1]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"995","DOI":"10.1007\/s00248-012-0159-y","article-title":"Harmful Cyanobacterial Blooms: Causes, Consequences, and Controls","volume":"65","author":"Paerl","year":"2013","journal-title":"Microb. Ecol."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"128","DOI":"10.1016\/j.hal.2019.05.006","article-title":"Environmental Factors Associated with Toxic Cyanobacterial Blooms across 20 Drinking Water Reservoirs in a Semi-Arid Region of Brazil","volume":"86","author":"Barros","year":"2019","journal-title":"Harmful Algae"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"71","DOI":"10.1007\/s11270-023-06782-y","article-title":"Cyanobacteria Harmful Algae Blooms: Causes, Impacts, and Risk Management","volume":"235","author":"Igwaran","year":"2024","journal-title":"Water Air Soil Pollut."},{"key":"ref_4","doi-asserted-by":"crossref","unstructured":"Benayache, N.-Y., Nguyen-Quang, T., Hushchyna, K., McLellan, K., Afri-Mehennaoui, F.-Z., Boua\u00efcha, N., Benayache, N.-Y., Nguyen-Quang, T., Hushchyna, K., and McLellan, K. (2019). An Overview of Cyanobacteria Harmful Algal Bloom (CyanoHAB) Issues in Freshwater Ecosystems. 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