Harmful Algae最新文献

{"title":"The Great Atlantic Sargassum Belt: Impacts on the Central and Western Caribbean–A review","authors":"R.E. Rodríguez-Martínez ,&nbsp;E.G. Torres-Conde ,&nbsp;J. Rosellón-Druker ,&nbsp;N. Cabanillas-Terán ,&nbsp;U. Jáuregui-Haza","doi":"10.1016/j.hal.2025.102838","DOIUrl":"10.1016/j.hal.2025.102838","url":null,"abstract":"<div><div>Pelagic <em>Sargassum</em> spp. blooms pose a complex challenge to the Caribbean coast, affecting ecological, economic, and social dimensions. Since the formation of the Great Atlantic <em>Sargassum</em> Belt in 2011, these blooms have become an annual occurrence, lasting up to nine months each year. The <em>Sargassum</em> that washes ashore in the Western and Central Caribbean can reach tens of thousands of cubic meters per kilometer annually. These algae can carry pollutants, pathogens, and exotic species to coastal zones. As the algae decay, toxic gases and leachates are released, posing significant health risks to humans and other species. Ecologically, <em>Sargassum</em> landings contribute to beach erosion, nearshore waters eutrophication and transition from sandy to muddy sediments, and oxygen depletion, leading to losses in seagrass meadows flora and fauna. Mangrove ecosystems, inlets, and bays face disruptions in their biochemistry, hydrodynamics, and ecology, potentially shifting from carbon sinks to sources of greenhouse gases. Economically, the impact is severe, threatening the tourism and fishing industries crucial to the affected countries' economies. Socially, the blooms affect various aspects of well-being, including health, job quality, and connections to nature. Although progress has been made in understanding the impacts of <em>Sargassum</em>, much of the research has been concentrated in Mexico, primarily focusing on the ecological effects on coastal and beach environments. However, considerable knowledge gaps remain regarding the impacts of <em>Sargassum</em> on the ecosystems, economies, and social well-being of many other countries and territories in the region.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"144 ","pages":"Article 102838"},"PeriodicalIF":5.5,"publicationDate":"2025-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143679978","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A novel hybrid cyanobacteria mapping approach for inland reservoirs using Sentinel-3 imagery","authors":"Thainara M.A. de Lima ,&nbsp;Claudio C.F. Barbosa ,&nbsp;Cristina S.F. Nordi ,&nbsp;Felipe N. Begliomini ,&nbsp;Vitor S. Martins ,&nbsp;Fernanda S.Y. Watanabe ,&nbsp;Raianny L.N. Wanderley ,&nbsp;Rejane S. Paulino","doi":"10.1016/j.hal.2025.102836","DOIUrl":"10.1016/j.hal.2025.102836","url":null,"abstract":"<div><div>Detecting and quantifying cyanobacteria algal bloom occurrence plays an important role in preventing public health risks and understanding aquatic ecosystem dynamics. Satellite remote sensing has been used as an important data source to estimate cyanobacteria biomass based on pigment concentration. Phycocyanin (PC) is a unique pigment of inland water cyanobacteria and has been widely used as a proxy for cyanobacteria algal biomass. Based on the PC absorption feature around 620 nm, scientific efforts have been made to develop bio-optical models for orbital satellite observations, but proposed PC models limit the retrievals at different concentration ranges and depend on empirical models calibrated for specific aquatic environments. This study proposes a hybrid machine learning approach for PC retrieval that efficiently adopts the optimal algorithm for specific PC concentration ranges. An <em>in-situ</em> dataset of 165 samples was collected between November 2020 and December 2021 to support full training and validation of the proposed method. First, a Random Forest algorithm was applied to classify PC-low-concentration waters (0 – ∼14 mg.m⁻³) and PC-high-concentration waters (∼14.1 – 300 mg.m⁻³). Then, for each defined class, an individual PC estimation algorithm was calibrated. The final PC-hybrid model was applied to atmospherically corrected Sentinel-3/OLCI imagery derived by three approaches (L2-WFR, 6SV, and ACOLITE). The PC hybrid-model performance was evaluated by comparing the estimated PC concentration from satellite and in situ measurements. The hybrid PC model estimates (median symmetric accuracy (ζ) = 25.35%) outperformed the individual PC algorithms calibrated for the entire range of PC concentration, proving the practical applicability for quantifying PC concentration in optically dynamic waters.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"144 ","pages":"Article 102836"},"PeriodicalIF":5.5,"publicationDate":"2025-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143562059","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Benthic cyanobacterial accumulations and associated cyanotoxins in coastal urban stormwater pond networks","authors":"Avery O. Tatters ,&nbsp;Courtney Clevenger ,&nbsp;Wendy K. Strangman ,&nbsp;Stuart Oehrle ,&nbsp;Raphael M. Kudela ,&nbsp;Jessica Aukamp ,&nbsp;Yongshan Wan","doi":"10.1016/j.hal.2025.102833","DOIUrl":"10.1016/j.hal.2025.102833","url":null,"abstract":"<div><div>Extensive cyanobacteria-dominated mats were observed during late summer of 2021 within coastal urban stormwater retention pond networks in northwest Florida. Common in residential communities across the region, such ponds may be routinely visited by humans, domestic and wild animals, and often contain a variety of aquatic life. To begin examining correlations between environmental factors and mat characteristics, we investigated the temporal heterogeneity of these networks with regards to presence of potentially toxic cyanobacteria, associated toxins, and other putative cyanobacterial compounds throughout the fall at several sites within the networks. Multiple toxin classes were detected in whole water and passive SPATT samples using targeted analysis including levels of cylindrospermopsin that exceeded national recreational guidelines. Non-targeted analysis also revealed a collection of potential cyanobacteria-associated compounds. Our results suggest that the benthic proliferations may be, at least in part, correlated with the intended functions of the stormwater treatment networks, which are nutrient and sediment removal. Furthermore, these retention ponds may serve as an episodic source of cyanotoxins to estuarine waters.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"144 ","pages":"Article 102833"},"PeriodicalIF":5.5,"publicationDate":"2025-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143580383","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":"Growth and anatoxin-a production of Microcoleus (Cyanobacteria) strains from streams in California, USA","authors":"Sydney M. Brown ,&nbsp;Joanna R. Blaszczak ,&nbsp;Robert K. Shriver ,&nbsp;R.Christian Jones ,&nbsp;Abeer Sohrab ,&nbsp;Ramesh Goel ,&nbsp;Gregory L. Boyer ,&nbsp;Bofan Wei ,&nbsp;Kalina M. Manoylov ,&nbsp;T.Reid Nelson ,&nbsp;Jordan M. Zabrecky ,&nbsp;Rosalina Stancheva","doi":"10.1016/j.hal.2025.102834","DOIUrl":"10.1016/j.hal.2025.102834","url":null,"abstract":"<div><div>Benthic cyanobacterial proliferations are an emerging concern globally due to their potential for toxin production and subsequent negative environmental and health impacts. <em>Microcoleus</em> is a common mat-forming genus reported to produce potent neurotoxin, anatoxin-a, ingestion of which has been associated with animal mortalities. Six different unialgal monoclonal strains of <em>Microcoleus</em> were isolated from streams in California and grown in batch culture for 49 days. The four toxic strains were identified using a polyphasic approach as belonging to the species <em>Microcoleus anatoxicus</em>, which expands its known distribution throughout the Klamath River and Rock Creek watersheds in northern California. The non-toxic strains from the Eel River belonged to <em>Microcoleus</em> sp. 1. Maximum toxin production occurred during the exponential growth phase, and peaked 6–13 days later in more toxic strains, with a persistently higher fraction of extracellular toxins compared to less toxic strains, which had maximum toxin concentrations at day 13. The proposed mechanism of toxin release into culture medium was through damage to the cell walls of unhealthy filaments. Peak toxin production was energetically expensive for all <em>M. anatoxicus</em> strains, evidenced by reduced specific growth rates at the time of peak toxin production, followed by quick recovery of cell division. Despite this, more toxic strains achieved faster maximum growth rates than the less toxic and non-toxic strains under luxurious nutrient culture conditions. Differential toxin and growth rate responses of <em>M. anatoxicus</em> strains from wide geographical ranges under the same laboratory-controlled conditions suggest high intraspecific variation, which may represent challenges for harmful algal blooms mitigation. More toxic strains have the potential to proliferate and consistently release extracellular anatoxins into the environment. This study provides a baseline to understanding the growth and toxin kinetics of two commonly occurring <em>Microcoleus</em> species in northern California which may help benthic harmful cyanobacteria management.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"144 ","pages":"Article 102834"},"PeriodicalIF":5.5,"publicationDate":"2025-03-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143580384","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Drivers of a window of opportunity for Dinophysis acuminata in a mussel seed-bank hotspot in Northwestern Patagonia","authors":"Ángela M. Baldrich ,&nbsp;Manuel Díaz ,&nbsp;Camilo Rodríguez-Villegas ,&nbsp;René Garreaud ,&nbsp;Lauren Ross ,&nbsp;Iván Pérez-Santos ,&nbsp;Camila Schwerter ,&nbsp;Pamela Carbonell ,&nbsp;Patricio A. Díaz","doi":"10.1016/j.hal.2025.102830","DOIUrl":"10.1016/j.hal.2025.102830","url":null,"abstract":"<div><div>Chilean shellfish production is a significant contributor to the world´s marine aquaculture industry (∼22 % of the global mussel production). Most of this activity takes place in the Patagonian fjords system of southern Chile. Reloncaví Fjord (∼41°S), in northwestern Patagonia, represents the largest mytilid seed supply source for Chilean mussel aquaculture. In this fjord, <em>Dinophysis acuminata</em> —a lipophilic toxins producer— has been frequently found above detection levels (10² cells L⁻¹) during the regular monitoring program, reaching maximum densities in the spring and summer seasons. The bloom development of <em>D. acuminata</em> has been associated with the stratification of the water column and prey (<em>Mesodinium</em> spp.) availability. However, the drivers underlying <em>D. acuminata</em> spatial and temporal dynamics in the fjord are still poorly understood. From January 2019 to March 2020, measurements of physicochemical parameters and water samples (0 – 20 m depth) were collected weekly, biweekly, and monthly to analyse the spatiotemporal distribution of <em>D. acuminata</em> and the water column structure, at a fixed station at the head of Reloncaví Fjord. <em>D. acuminata</em> was observed in summer and spring of 2019, with a maximum of 2.1 × 10³ cells L⁻¹ in the early summer of 2019. In contrast, <em>D. acuminata</em> was absent in the summer of 2020. Results from a redundancy analysis (RDA) and generalized linear models (GLM) suggested that water salinity, and diminished nitrite and silicate probably enhanced by a moderate rainfall deficit in summer of 2019, explained the presence of <em>D. acuminata</em>. Thus, the results of the 15 months of sampling, including two summer seasons, allowed us i) to elucidate environmental drivers that provided a window of opportunity for <em>D. acuminta</em> population growth, and ii) to highlight that the abundance and distribution of a stress-tolerant species is a multifactorial response in which slight changes in specific environmental conditions can have a large influence.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"144 ","pages":"Article 102830"},"PeriodicalIF":5.5,"publicationDate":"2025-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143627944","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":"Comparative genomic and phylogenetic analysis of mitochondrial genomes of the Pseudo-nitzschia HAB species","authors":"Ziyan He ,&nbsp;Hui Wang ,&nbsp;Yang Chen ,&nbsp;Nansheng Chen","doi":"10.1016/j.hal.2025.102829","DOIUrl":"10.1016/j.hal.2025.102829","url":null,"abstract":"<div><div>The genus <em>Pseudo-nitzschia</em> within Bacillariophyta (diatoms) is best known for its rich collection of toxigenic harmful algal bloom (HAB) species capable of producing the neurotoxin domoic acid (DA), which causes amnesic shellfish poisoning (ASP) in humans. Molecular markers such as 18S rDNA, ITS1, and ITS2 have been applied to facilitate <em>Pseudo-nitzschia</em> species identification because morphology-based methods often could not adequately distinguish different species due to their morphological similarities and plasticity. In this study, we constructed mitochondrial genomes (mtDNAs) for 11 <em>Pseudo-nitzschia</em> species and assessed their utility as “super-barcodes” for species identification and evolutionary analysis. These mtDNAs exhibited conserved genome structures despite variability in repeat regions. A potential <em>tatA-tatC</em> gene fusion event was observed in a single <em>Pseudo-nitzschia</em> species <em>P. brasiliana</em>. We also observed intron variability in <em>cox1</em> genes. Phylogenetic analyses of mtDNAs, chloroplast genomes (cpDNAs), and nuclear ribosomal DNA (nrDNA) arrays revealed consistent results, supporting the closely related but distinct clustering of the genera <em>Fragilariopsis</em> and <em>Pseudo-nitzschia</em>. We further designed a high-resolution molecular marker <em>tatA</em> for species identification based on the comparative analysis of these mtDNAs, which could be used to track <em>Pseudo-nitzschia</em> diversity. These findings offer new genome resources and new insights into the genetic evolution and classification of <em>Pseudo-nitzschia</em>, underscoring the need for continued research in this field.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"144 ","pages":"Article 102829"},"PeriodicalIF":5.5,"publicationDate":"2025-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143512228","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":"Responses of mussel farms to harmful algal bloom governance are shaped by the scale of production: Implications for equitable blue economy","authors":"Vicente I. Villalobos ,&nbsp;Diego F. Morales-Torres ,&nbsp;Nelson Valdivia ,&nbsp;María I. Rivera-Hechem ,&nbsp;Ricardo Giesecke ,&nbsp;Andrea Piñones ,&nbsp;Jorge I. Mardones ,&nbsp;José Garcés-Vargas ,&nbsp;Cristian J. Segura ,&nbsp;Jorge M. Navarro ,&nbsp;Luis Outeiro","doi":"10.1016/j.hal.2025.102821","DOIUrl":"10.1016/j.hal.2025.102821","url":null,"abstract":"<div><div>Small-scale aquaculture is essential to balance environmental health, economic growth, and social equity. However, the increasing frequency of Harmful Algae Blooms (HABs), commonly known as red tides, present a significant risk to both aquatic ecosystems and human well-being, threatening the productivity of the sector. This study investigates the impact of HAB-induced closures on mussel farming in Chile, the world's second-largest mussel industry, with a focus on how farm size influences resilience and adaptive capacity. With a 19-year dataset (2003–2021) covering small (&lt;3 ha), medium (3–8 ha), and large (&gt;8 ha) mussel farms, we analysed the temporal and spatial distribution of HAB closures and their effects on mussel export volumes. Using Generalized Additive Mixed Models (GAMMs), we reveal that small farms, while attempting rapid post-closure recovery, are more vulnerable to prolonged economic stress, primarily due to limited access to adaptive resources and fluctuating market prices. Larger farms, on the other hand, demonstrate a delayed but stable recovery, benefiting from superior spatial positioning and access to capital. While the industry showed sustained growth at the regional level, our analysis demonstrated an asymmetric, size-dependent pattern on local responses, where small producers are more vulnerable to unexpected climatic events and market fluctuations. Given the increasing frequency of HABs due to climate change, our findings underscore the need for equitable governance in the blue economy to prevent widening inequalities between small and large producers. Policy recommendations include enhanced monitoring systems, increased access to financial and technical resources for small-scale farmers, and market diversification to improve resilience against environmental disruptions.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"144 ","pages":"Article 102821"},"PeriodicalIF":5.5,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143488267","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Assessment of the sub-lethal impacts of Karenia brevis on hard clams, Mercenaria campechiensis","authors":"Jessica Donaldson ,&nbsp;Aileen Maldonado ,&nbsp;Joseph H Bisesi ,&nbsp;William Geisbert ,&nbsp;Richard H Pierce","doi":"10.1016/j.hal.2025.102820","DOIUrl":"10.1016/j.hal.2025.102820","url":null,"abstract":"<div><div><em>Karenia brevis,</em> a toxin-producing dinoflagellate, has been implicated in frequent harmful algal blooms (HABs) in the Gulf of Mexico. Shellfish species, such as <em>Mercenaria campechiensis,</em> have high resilience to <em>K. brevis</em> exposure causing high accumulation and retention of brevetoxins within their tissues. The current study aimed to analyze the accumulation and depuration of brevetoxins in <em>M. campechiensis</em> exposed to 100,000 cells L^-1 for two weeks. The second aim was to identify the potential detoxification enzymes in <em>M. campechiensis</em> as well as potential enzymes representative of stress to see if moderate concentrations lead to stress in exposed <em>M. campechiensis.</em> This was done by exposing <em>M. campechiensis</em> to a continuous flow of <em>K. brevis</em>, followed by a 47-day depuration period. There was an increase in brevetoxin concentration during the exposure with a rapid decrease at the onset of the depuration period. This was followed by a gradual decrease with detectable toxins in the exposed clam tissue for the duration of the experiment. While there was detectable toxin during the depurations, the concentrations were below the NSP level for BTX-2 by day 14 indicating <em>M. campechiensis</em> would potentially be safe for consumption after two weeks following exposure to a moderate <em>K. brevis</em> concentration. Fold change of AChE activity significantly increased in the exposure tank when compared to the controls following the exposure period. Fold change of GST activity from control significantly decreased in the exposure tank compared to the controls on 14 d exposure. Both changes in enzyme activity support the findings that a moderate concentration of <em>K. brevis</em> may induce stress in <em>M. campechiensis.</em> Ultimately, the results of the current study further highlight the importance of the <em>K. brevis</em> regulatory limits as it can prevent possible neurotoxic shellfish poisoning in people who eat contaminated shellfish as it prevents the consumption of shellfish exposed to moderate and high concentrations of <em>K. brevis.</em></div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"143 ","pages":"Article 102820"},"PeriodicalIF":5.5,"publicationDate":"2025-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143445582","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":"The cytotoxic and hemolytic potential of karmitoxin from Karlodinium armiger and how it interacts with sterols","authors":"Hélène-Christine Prause ,&nbsp;Nadine Hochmayr ,&nbsp;Yanan Yu ,&nbsp;Thomas Ostenfeld Larsen ,&nbsp;Per Juel Hansen ,&nbsp;Giorgia Del Favero ,&nbsp;Doris Marko ,&nbsp;Allen Place ,&nbsp;Elisabeth Varga","doi":"10.1016/j.hal.2025.102817","DOIUrl":"10.1016/j.hal.2025.102817","url":null,"abstract":"<div><div>Karmitoxin, produced by <em>Karlodinium armiger</em>, is structurally related to karlotoxin and amphidinols, two potent ichthyotoxic hemolysins with high affinity for sterols. Given these structural similarities, karmitoxin is believed to exhibit comparable toxic effects. Cytotoxicity was assessed in the fish gill cell line RTgill-W1 and the human epithelial colon cell line HCEC-1CT. The hemolytic potential with and without added sterols was tested on fish erythrocytes to investigate possible impacts of toxin-sterol interactions. Sterol interactions were further evaluated using surface plasmon resonance. A 3-h incubation returned an EC₅₀ of 111 and 175 nM in RTgill-W1 and in HCEC-1CT cells, respectively. Lactate dehydrogenase (LDH) release increased with toxin concentration, reaching 11 % in the fish and 40 % in the human cell line. Extended exposure (24 h) increased the toxicity in RTgill-W1 cells (EC₅₀ 74 nM, 40 % LDH release). In parallel, hemolytic potential of karmitoxin was confirmed, as well as its interaction with free sterols. Interaction kinetics revealed complex stabilities with k_d(s⁻¹) constants of 1.13 × 10⁻² (cholesterol), 5.48 × 10⁻³ (epicholesterol), and 4.72 × 10⁻³ (ergosterol). Interaction with cholesterol followed the single-exponential model well, while data indicated more complex binding with epicholesterol and ergosterol. Altering the RTgill-W1 cholesterol content did not impact cytotoxicity at the tested concentration. Overall, karmitoxin showed potent cytotoxic and hemolytic properties in human and fish models. Complex formation with sterols may play a role in membrane targeting, yet cellular cholesterol quantity might not affect cytotoxicity.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"143 ","pages":"Article 102817"},"PeriodicalIF":5.5,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143419526","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Nutrient limitation and seasonality associated with phytoplankton communities and cyanotoxin production in a large, hypereutrophic lake","authors":"Gabriella M. Lawson ,&nbsp;Jakob L. Young ,&nbsp;Zachary T. Aanderud ,&nbsp;Erin F. Jones ,&nbsp;Samuel Bratsman ,&nbsp;Jonathan Daniels ,&nbsp;Madeleine P. Malmfeldt ,&nbsp;Michelle A. Baker ,&nbsp;Benjamin W. Abbott ,&nbsp;Scott Daly ,&nbsp;Hans W. Paerl ,&nbsp;Greg Carling ,&nbsp;Brian Brown ,&nbsp;Raymond Lee ,&nbsp;Rachel L. Wood","doi":"10.1016/j.hal.2025.102809","DOIUrl":"10.1016/j.hal.2025.102809","url":null,"abstract":"<div><div>Though freshwater harmful algal blooms have been described and studied for decades, several important dynamics remain uncertain, including the relationships among nutrient concentrations, phytoplankton growth, and cyanotoxin production. To identify when and where nutrients limit phytoplankton, cyanobacteria, and cyanotoxins, we conducted in situ bioassay studies. We added nitrogen (N), phosphorus (P), or N + P across various seasons in water collected from three locations across Utah Lake, one of the largest freshwater lakes in the western U.S. This shallow, hypereutrophic lake provides a powerful testbed for quantifying nutrient-growth-toxin interactions. We assessed a range of parameters over time, including photopigment concentrations, phytoplankton abundance (cell counts), cyanotoxins, and nutrient concentrations. Despite high background nutrient concentrations in lake water, phytoplankton abundance and composition were strongly affected by nutrient addition. Phosphorus limitation was more common in the spring, with N limitation and N + P limitation becoming more common in the fall. Nutrient additions were positively associated with cyanobacteria (<em>Microcystis, Aphanocapsa, Dolichospermum, Merismopedia, Aphanizomenon</em> spp<em>.</em>), eukaryotes (<em>Aulacoseira, Desmodesmus</em> spp<em>.</em>), and two taxonomical categories of phytoplankton (i.e., unicellular and colonial green algae). When detected, anatoxin-a was positively associated with <em>Aphanizomenon</em> and negatively associated with <em>Microcystis</em> spp. However, overall cyanotoxin concentrations were not associated with cyanobacterial cell density but varied seasonally. These findings highlight the importance of considering seasonal nutrient availability dynamics and provide insights into specific nutrient targets, species, and cyanotoxins that play a significant role in the health and management of similar eutrophic lake environments around the world.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"143 ","pages":"Article 102809"},"PeriodicalIF":5.5,"publicationDate":"2025-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143403516","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}