Harmful Algae最新文献

{"title":"RT-PCR assay development of ITS and toxin gene regions of, Aetokthonos hydrillicola, a known epiphyte of the invasive species Hydrilla verticillata","authors":"Theresa K. Hattenrath ,&nbsp;Erika Klar ,&nbsp;Katherine C. Callaghan ,&nbsp;Madelyn Caldwell ,&nbsp;Christopher Tucker ,&nbsp;Catherine A. McGlynn ,&nbsp;Susan B. Wilde","doi":"10.1016/j.hal.2025.103029","DOIUrl":"10.1016/j.hal.2025.103029","url":null,"abstract":"<div><div><em>Aetokthonos hydrillicola</em> is a toxic epiphytic cyanobacterium often associated with invasive water thyme (Hydrilla), <em>Hydrilla verticillata. A. hydrillicola</em> can produce a potent brominated neurotoxin, aetokthonotoxin (AETX), and a cytotoxic dolastatin analog, aetokthonostatin (AEST). The continued expansion of invasive Hydrilla across the United States, including New York State (NYS) waters, has highlighted the need for an accurate method to detect <em>A. hydrillicola</em> and its toxins due to the potential public health implications. A fast and accurate method for detecting <em>A. hydrillicola</em> and its toxins in aquatic plant materials was developed by targeting the rRNA ITS region (ITS1, ITS2) and biosynthetic gene clusters of AETX (aetxE, aetxA) and AEST (aestF, aestK). Samples from Southeastern United States and Southeastern NYS lakes and ponds were analyzed using the developed RT-PCR assays. Hydrilla from Lake Sebago tested positive for AEST genes, but was negative for both ITS and AETX genes, despite <em>A. hydrillicola</em> being confirmed via light microscopy. This is consistent with toxin analysis via LCMS finding no measurable AETX. The lack of AETX genes and the inability to amplify the Lake Sebago <em>A. hydrillicola</em> using current ITS primers/probes suggests that this is likely a different genetic variant. This data also suggests that AEST genes are likely conserved across genetic variants of <em>A. hydrillicola</em>. These RT-PCR assays will allow for an increased throughput of lakes surveyed for the presence of <em>A. hydrillicola</em> and its toxins, enabling environmental managers to make swift decisions regarding the prevention or reduction of impacts on wildlife and public health.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"151 ","pages":"Article 103029"},"PeriodicalIF":4.5,"publicationDate":"2025-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145577594","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluating the ten-year health impact of hydrogen sulfide (H2S) and ammonia (NH3) exposure from sargassum seaweed invasions in the Caribbean: Public health implications","authors":"Dabor Resiere ,&nbsp;Jonathan Florentin ,&nbsp;Rémi Névière","doi":"10.1016/j.hal.2025.103027","DOIUrl":"10.1016/j.hal.2025.103027","url":null,"abstract":"<div><div>Since 2011, the Caribbean region—including Martinique, Guadeloupe, and French Guiana—has experienced increasing invasions of Sargassum seaweed, leading to significant environmental, economic, and public health challenges. This study evaluates the health impacts of hydrogen sulfide (H₂S) and ammonia (NH₃) emissions from decomposing Sargassum on affected populations. Data were collected from 850 patients admitted to the University Hospital of Martinique between January 2018 and September 2024, all of whom had been exposed to Sargassum emissions for an average of 2–3 months annually. Reported symptoms included neurological (80%), respiratory (80%), and digestive (70%) disorders, as well as central sleep apnea (60%). Pulmonary inflammation was assessed through spirometry and fractional exhaled nitric oxide (FeNO) levels. Psychological and social impacts were also documented. Findings indicate a toxicological syndrome associated with chronic Sargassum exposure, resembling acute H₂S inhalation at low concentrations. This study underscores the urgent need for multidisciplinary research to mitigate these health impacts, calling for immediate attention from governments, international stakeholders, and environmental experts.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"152 ","pages":"Article 103027"},"PeriodicalIF":4.5,"publicationDate":"2025-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145735222","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Strengthening regional cooperation: The role of the Cartagena Convention in addressing the sargassum inundations challenge in the wider Caribbean","authors":"Susana Perera-Valderrama ,&nbsp;Geraldine Conruyt ,&nbsp;Lucile Rossin ,&nbsp;Auriane Petit ,&nbsp;Tamoy Singh-Clarke ,&nbsp;Christopher Corbin","doi":"10.1016/j.hal.2025.103028","DOIUrl":"10.1016/j.hal.2025.103028","url":null,"abstract":"<div><div>The ongoing presence of Sargassum inundations has led to various national and regional initiatives in the Wider Caribbean Region. However, these efforts often lack cohesion, resulting in overlap and duplication, missed opportunities for sharing knowledge and best practices and uncoordinated resource mobilization and partnerships. This review article emphasizes the current role and potential of the Cartagena Convention as an important regional mechanism for cooperation, harmonization, and decision-making. Through the work of the Convention and its Protocols, several cooperative solutions have been implemented on various topics relating to the protection, conservation and sustainable use of marine and coastal biodiversity and the control, reduction and prevention of pollution from land and marine-based sources. The Secretariat, supported by Regional Activity Centres and partner agencies are well placed to foster greater collaboration in addressing the Sargassum inundation issue. We provide an overview of the regional response to Sargassum management in the Caribbean including current gaps and challenges. We identify some key areas requiring regional cooperation, including enhanced monitoring of Sargassum impacts, standardized response protocols, policy harmonization, and public awareness initiatives. Finally, we propose some next steps, including further leveraging the legal framework provided by the Cartagena Convention and its Protocols to support the Caribbean countries and the broader Wider Caribbean Region in strengthening cooperation on Sargassum-related issues, facilitating the adoption of common standards for its management, and promoting collaborative research initiatives.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"151 ","pages":"Article 103028"},"PeriodicalIF":4.5,"publicationDate":"2025-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145527429","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Occurrence of toxic microalgae and associated toxins in the western Black Sea: insights from the PHYCOB cruise in September 2021","authors":"Nina Dzhembekova ,&nbsp;Fuat Dursun ,&nbsp;Urban Tillmann ,&nbsp;Ivelina Zlateva ,&nbsp;Oana Vlas ,&nbsp;Nataliya Slabakova ,&nbsp;Kristof Möller ,&nbsp;Snejana Moncheva ,&nbsp;Florian Koch ,&nbsp;Laura Boicenco ,&nbsp;Ertuğrul Aslan ,&nbsp;Sabri Mutlu ,&nbsp;Ivan Popov ,&nbsp;Satoshi Nagai ,&nbsp;Bernd Krock","doi":"10.1016/j.hal.2025.103025","DOIUrl":"10.1016/j.hal.2025.103025","url":null,"abstract":"<div><div>Harmful Algal Blooms (HABs) represent a significant global challenge to human health, economies, and ecosystems, including those of the Black Sea. Despite previous reports of potentially toxic microalgae and phycotoxins in the basin, the taxonomy and occurrence of toxigenic species and their associated toxins remain poorly resolved. During the PHYCOB cruise in September 2021, the diversity and distribution of toxigenic microalgae and phycotoxins were investigated across 23 stations in the western Black Sea, covering Bulgarian and Romanian waters. Numerous potentially toxic microalgal taxa were identified using complementary morphological (light microscopy and scanning electron microscopy) and molecular (DNA metabarcoding) methods. The genus <em>Pseudo-nitzschia</em> was the only representative of potentially toxic diatoms, but no domoic acid was found. Among toxic dinoflagellates, <em>Dinophysis</em> spp., <em>Protoceratium reticulatum, Lingulaulax polyedra</em>, and <em>Gonyaulax</em> spp<em>.</em> were frequently observed, along with the related pectenotoxins and yessotoxins. Species distribution modelling indicated that the western Black Sea provides favorable conditions for <em>Dinophysis</em> spp., <em>L. polyedra</em>, and <em>P. reticulatum</em>. Additionally, several <em>Alexandrium</em> species were identified, including the first record of <em>A. fragae</em> in the basin, along with the detection of the associated phycotoxins (GTX-2/3 and GDA). This study provides the first integrated assessment combining light and scanning electron microscopy, DNA metabarcoding, and chemical analyses of toxigenic microalgae in field samples from the western Black Sea, contributing to an improved understanding of their region-specific profiles.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"151 ","pages":"Article 103025"},"PeriodicalIF":4.5,"publicationDate":"2025-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145688846","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A digital PCR assay for the dabA gene involved in domoic acid biosynthesis by Pseudo-nitzschia spp","authors":"Chloe Weinstock ,&nbsp;Christina Preston ,&nbsp;John K. Brunson ,&nbsp;William Ussler ,&nbsp;Holly Bowers ,&nbsp;Kevan Yamahara ,&nbsp;Greg Doucette ,&nbsp;John Ryan ,&nbsp;Andrew Allen ,&nbsp;Christopher Scholin ,&nbsp;James Birch","doi":"10.1016/j.hal.2025.103024","DOIUrl":"10.1016/j.hal.2025.103024","url":null,"abstract":"<div><div>Successful harmful algal bloom (HAB) prediction and monitoring employs a variety of observational and research strategies. We add to the existing suite of tools for detecting toxigenic <em>Pseudo-nitzschia</em> diatoms by developing a novel digital PCR (dPCR) assay targeting a key gene of the domoic acid biosynthetic pathway, dabA. Sequence alignments and synthetic gene fragments of dabA genes from <em>Pseudo-nitzschia australis, P. multiseries, P. multistriata</em>, and <em>P. seriata</em>, along with the closely-related red-algal genes kabA and radA, were used to design a dPCR assay and assess its specificity. This dPCR assay was demonstrated to be specific for dabA and can quantify concentrations &gt;1 copy µL^-1 in a reaction. The biogeography of published dabA genes suggests that the assay may be useful globally for target species. When screening a culture collection of <em>Pseudo-nitzschia</em> isolated from coastal California, the dPCR assay detected dabA genes from three of the eleven species tested<em>.</em> In samples collected during field campaigns in 2022 off Santa Barbara, CA and in 2023 in Monterey Bay, CA during toxic HAB events, <em>Pseudo-nitzschia</em> dabA genes were only detected in Monterey Bay samples. While the dPCR assay does not capture all dabA diversity, it is specific and provides a targeted means to assess the genetic potential of a toxic HAB event by dominant and potent toxin-producing <em>Pseudo-nitzschia</em> species in coastal California. Because dabA expression is a key indicator of DA production, using the assay to quantify gene transcription could speed the acquisition of data needed to forecast HABs before toxin is detected.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"151 ","pages":"Article 103024"},"PeriodicalIF":4.5,"publicationDate":"2025-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145577596","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Morphological, molecular and toxinological characterization of potentially toxigenic microalgal strains from the western Black Sea","authors":"Fuat Dursun ,&nbsp;Nina Dzhembekova ,&nbsp;Bernd Krock ,&nbsp;Jan Tebben ,&nbsp;Urban Tillmann","doi":"10.1016/j.hal.2025.103026","DOIUrl":"10.1016/j.hal.2025.103026","url":null,"abstract":"<div><div>Harmful algal blooms (HAB) of various toxic microalgae negatively affect the Black Sea but there is limited data on the sources of phycotoxins in this area. During the PHYCOB cruise in September 2021, two strains of one diatom and thirty strains of ten dinoflagellate species of potentially toxigenic plankton were characterized in terms of morphology, phylogeny, toxin profiles, and toxin cell quotas. Twenty strains of potentially yessotoxins (YTXs) producing dinoflagellate species were investigated. All six strains of <em>Protoceratium reticulatum</em> contained yessotoxin (YTX), with cell quotas between 1.9 and 5.4 pg cell^-1. Additionally, several YTX variants were detected in minor amounts in nine of twelve strains of <em>Lingulaulax polyedra</em>, whereas no YTXs were detected in two strains of other gonyaulacoids (<em>Gonyaulax</em> sp. and <em>Sourniaea diacantha</em>). All strains of <em>Alexandrium</em> spp. (four strains of <em>A. tamutum</em>, one strain each of <em>A. andersonii, A. ostenfeldii</em>, and <em>A. pseudogonyaulax</em>) were analyzed for all toxins known to be produced by the genus. None of the strains contained detectable levels of paralytic shellfish toxins (PSTs) or gymnodimines. <em>A. pseudogonyaulax</em> produced goniodomine A (GDA) and GDA-seco acid at cellular levels of 14.0 and 0.33 pg cell^-1, respectively. Moreover, four previously unreported spirolide analogues (SPX) were detected in the <em>A. ostenfeldii</em> strain, with cell quotas between 1.0 and 1.6 pg cell^-1. All strains of potentially ichthyotoxic species (<em>Karlodinium</em> sp., <em>Polykrikos hartmanii</em>) did not show extracellular lytic activity. In conclusion, these findings improve our understanding of the potential sources, diversity and dynamics of phycotoxins in the Black Sea.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"151 ","pages":"Article 103026"},"PeriodicalIF":4.5,"publicationDate":"2025-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145688823","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Temperature dependent response of microcystin-LR in acclimated M. aeruginosa PCC 7806","authors":"Pierre-Louis Lalloué,&nbsp;Clarisse Mallet,&nbsp;Alexandre Bec,&nbsp;Apostolos-Manuel Koussoroplis,&nbsp;Fanny Perrière,&nbsp;Delphine Latour","doi":"10.1016/j.hal.2025.103018","DOIUrl":"10.1016/j.hal.2025.103018","url":null,"abstract":"<div><div>As climate change raises global temperatures and increases the frequency of cyanobacterial blooms, understanding how rising mean temperatures affect cyanotoxin content is crucial. However, no clear consensus exists, and the use of different methodologies, including different units of measurement and experimental conditions could significantly alter the yield of the relationship between temperature and toxins content. In this study, we assessed free microcystin content and cell volume in <em>Microcystis aeruginosa</em> PCC 7806 acclimated to seven temperatures spanning its entire thermal niche. This experimental design firstly highlighted the significant reduction in cell volume with rising temperatures between 17 °C and 29 °C. As a result, when the microcystin concentration was normalized by its cell volume, its temperature response was transformed from a negative correlation to a bell-shaped curve, with higher free MC-LR content measured at an estimated optimum temperature of 25.5 °C, close to the thermal growth optimum of <em>Microcystis aeruginosa</em>. These findings provide new insights into the effects of climate warming on microcystin content.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"151 ","pages":"Article 103018"},"PeriodicalIF":4.5,"publicationDate":"2025-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145527430","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Osmolyte chemical diversity in Lingulaulax polyedra red tides: a critical overlooked factor to respiratory irritations?","authors":"Eva Ternon ,&nbsp;Evgenia Glukhov ,&nbsp;Marine Vallet ,&nbsp;Julie Dinasquet ,&nbsp;Melissa L. Carter ,&nbsp;Lena Gerwick ,&nbsp;William H. Gerwick ,&nbsp;Clarissa Anderson","doi":"10.1016/j.hal.2025.103009","DOIUrl":"10.1016/j.hal.2025.103009","url":null,"abstract":"<div><div>The detrimental effects on human health sometimes observed during blooms of <em>Lingulaulax polyedra</em> have been formerly attributed to the yessotoxin analogs this species produces. In this paper we show that natural concentrations of yessotoxin analogs present in seawater and sea spray aerosols during an unprecedented <em>L. polyedra</em> bloom in 2020 in Southern California did not induce inflammation in mammal macrophage cells, questioning the role played by yessotoxin in causing respiratory irritations. This bloom was associated with unprecedented levels of particulate dimethylsulfoniopropionate (2.74 ± 1.63 to 10.11 ± 1.39 µM), gonyol and several new structural analogs of gonyol. We profiled the metabolic content of dinoflagellate cells and recorded increasing amounts of quaternary amines of the betaine family (carnitine, actinin, ectoine) as the bloom progressed. Being precursors of sulfur and nitrogenous small volatile compounds, we hypothesize that, in addition to their recognized role in climate processes, these sulfur and nitrogenous osmolytes may also play a key role in health-related issues reported during intense <em>L. polyedra</em> blooms.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"151 ","pages":"Article 103009"},"PeriodicalIF":4.5,"publicationDate":"2025-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145527118","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Controlling harmful algal blooms (HABs) in marine waters: Review of current status and future prospects","authors":"Donald M. Anderson ,&nbsp;Mark L. Wells ,&nbsp;Vera L. Trainer ,&nbsp;Marc Suddleson ,&nbsp;Kevin Claridge ,&nbsp;Kathryn J. Coyne ,&nbsp;Quay Dortch ,&nbsp;Christopher J. Gobler ,&nbsp;Cynthia A. Heil ,&nbsp;Nobuharu Inaba ,&nbsp;H. Dail Laughinghouse IV ,&nbsp;Jorge I. Mardones ,&nbsp;Natsuko Nakayama ,&nbsp;Taegyu Park ,&nbsp;Melissa B. Peacock ,&nbsp;Kaytee Pokrzywinski ,&nbsp;Heather Raymond ,&nbsp;Jennifer H. Toyoda ,&nbsp;Dean Trethewey ,&nbsp;Petra M. Visser ,&nbsp;Yongquan Yuan","doi":"10.1016/j.hal.2025.102989","DOIUrl":"10.1016/j.hal.2025.102989","url":null,"abstract":"<div><div>The societal, economic, geographic, and environmental impacts from marine harmful algal blooms (HABs) have increased in many regions around the world. The growing array of impacts is large and varied, threatening human health, marine and freshwater wildlife, and ecosystems upon which many nations rely on for food, recreation, tourism, and a plethora of other goods and services. Although the HAB burden has grown substantially over the past few decades, marine and estuarine HAB control remains one of the least developed areas of HAB science. The disconnect between HAB control needs and solutions stems in part from public, stakeholder, and scientific uncertainties about the balance between benefits and potentially undesirable environmental consequences. Other more practical challenges can include substantial regulation of in situ testing, scaling up laboratory-proven technologies to attack widespread blooms that can move in three dimensions in open marine waters, and an immature commercial market. Here we describe the status of control strategies targeting marine coastal and estuarine HABs, in particular those few approaches that have been tested in mesocosm or field applications. We identify the regulatory support, targeted science, investments, and public outreach that will be needed to accelerate the availability of applications for controlling HABs in marine waters worldwide.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"150 ","pages":"Article 102989"},"PeriodicalIF":4.5,"publicationDate":"2025-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145525833","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Spatial distribution and diversity of mcyA gene-carrying cyanobacteria in planktic and benthic communities of Swiss alpine lakes","authors":"Anna Carratalà ,&nbsp;Lisa Morales ,&nbsp;Bastiaan W Ibelings","doi":"10.1016/j.hal.2025.103007","DOIUrl":"10.1016/j.hal.2025.103007","url":null,"abstract":"<div><div>Cyanobacteria are notorious for producing harmful toxins, including microcystins, which can severely impact animal and human health. In Swiss alpine lakes, past episodes of cattle deaths have been linked to acute hepatotoxicosis caused by microcystins from benthic cyanobacteria but to date not much is known about the diversity of microcystin-producing cyanobacteria in these ecosystems, their spatial distribution or favorable ecological niches. In this study, we examined the presence and distribution of cyanobacteria communities across 31 alpine lakes in Switzerland, conducting a comparative survey of both planktic and benthic environments. The goal of this study was to better understand the composition and distribution of cyanobacterial communities found in the Swiss Alps that may produce microcystins, as well as to explore their association with selected bioclimatic variables. A total of 64 biomass samples were collected from high-altitude lakes in the Alps between June and October 2022. We used digital PCR (dPCR) to quantify the <em>mcyA</em> gene, a marker for cyanobacteria carrying microcystin genes, and performed high throughput 16S rRNA sequencing to characterize the taxonomic diversity of cyanobacterial communities. The obtained results revealed that 80 % of the planktic samples and 91 % of the benthic samples tested positive for the <em>mcyA</em> gene, indicating the widespread presence of <em>mcyA</em> carrying cyanobacteria in these lakes. Benthic environments showed comparable or higher <em>mcyA</em> concentrations per unit biomass to planktic samples, taken from the same locations, with biofilms and rock mats exhibiting the highest levels. Moran’s I statistic revealed significant spatial clustering of <em>mcyA</em>-carrying cyanobacteria, suggesting the presence of higher-risk locations in the Alps. Principal component analysis (PCA) identified lower precipitation levels as the most influential tested environmental factor driving this clustering. 16S rRNA analysis further revealed distinct cyanobacterial community compositions between planktic and benthic environments in remote altitude lakes, with genera <em>Phormidesmis</em> and <em>Leptolyngbya</em> dominant in benthic habitats, while <em>Pseudanabaena</em> and <em>Tychonema</em> were more prevalent in planktic samples. Our findings suggest that water flow may play a significant role in driving the proliferation of <em>mcyA</em> carrying cyanobacteria in high altitdue lakes of the Swiss Alps and highlight the need for integrated monitoring of both benthic and planktic cyanobacteria to correctly assess the risk of microcystin exposure in alpine lakes.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"151 ","pages":"Article 103007"},"PeriodicalIF":4.5,"publicationDate":"2025-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145442614","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}