Harmful Algae最新文献

{"title":"Seasonal dynamics of biotoxins and potentially toxic phytoplankton in three Baltic Sea blue mussel farms","authors":"Malin Olofsson ,&nbsp;Martin Karlsson ,&nbsp;Kimberly Melkersson ,&nbsp;Susanna Minnhagen ,&nbsp;Malin Persson ,&nbsp;Martin Reutgard ,&nbsp;Manuela Seehauser ,&nbsp;Aida Zuberovic Muratovic","doi":"10.1016/j.hal.2025.102885","DOIUrl":"10.1016/j.hal.2025.102885","url":null,"abstract":"<div><div>Cyanobacterial blooms are common in the Baltic Sea during summer, and even though several cyanobacteria are toxin producers, many organisms still ingest them as feed. These and other phytoplankton toxins can be detected in blue mussels accumulating over the season, which represents a potential health hazard for shellfish consumers. On a global scale, biotoxins therefore need to be quantified in shellfish before human consumption. We monitored 11 different groups of biotoxins in three blue mussel farms and the composition of 23 potentially toxin producing phytoplankton taxa from March to November 2022. None of the biotoxins were above available health guideline values nor regulated levels. However, the well-known cyanobacterial toxin in the Baltic Sea, nodularin, produced by <em>Nodularia spumigena</em>, was detected in net- and rope-farmed mussels throughout the summer, with the highest concentration of 47 µg kg^-1. In contrast, the less studied toxin cylindrospermopsin was only present in mussels in early spring and late fall (surface water temperature approx. 2–10 °C), with the maximum concentration of 19.7 µg kg^-1 in April, where <em>Aphanizomenon</em> is a potential producer, but yet not confirmed. Further, <em>Dinophysis acuminata</em>, a potential producer of Diarrhetic Shellfish Toxins (DSTs), was observed above warning levels at two sites with up to 2 400 individuals L^-1, although the found concentration of 73 µg kg^-1 is below the regulated level for DST group (160 µg kg^-1). Altogether emphasizing that high species abundance does not necessarily result in a high toxin accumulation. On the other hand, mussels can serve effectively as indicator species, detecting the presence of novel toxins when producer abundance is low. As no period of the year was completely toxin-free, quantitative analysis is recommended when mussels are to be harvested.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"147 ","pages":"Article 102885"},"PeriodicalIF":5.5,"publicationDate":"2025-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144098613","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":"Long-term spatiotemporal variability and regime classification of Chlorophyll-a concentrations in Lake Erie using satellite products","authors":"Taeho Kim ,&nbsp;HaeDeun Lee ,&nbsp;SooHyun Yang ,&nbsp;GunHyeong Lee ,&nbsp;Jihoon Shin ,&nbsp;YoonKyung Cha","doi":"10.1016/j.hal.2025.102896","DOIUrl":"10.1016/j.hal.2025.102896","url":null,"abstract":"<div><div>Monitoring chlorophyll-a (Chl-a) concentrations in Lake Erie is crucial for managing harmful algal blooms (HABs) that pose risks to water quality and public health. While in-situ Chl-a monitoring continues, its ability to capture the overall Chl-a patterns across the lake is limited by local heterogeneity. Satellite products address this limitation by providing broader spatiotemporal coverage, overcoming the constraints of point-based measurements. Among the nine satellite products evaluated, MODIS-Terra was selected as the optimal choice due to its strong correlation with in-situ measurements (ρ = 0.71) and extensive long-term data availability (60.08 % pixel availability on valid dates). Using MODIS-Terra data, we analyzed the long-term spatiotemporal Chl-a dynamics in Lake Erie over a 24-year period (2000–2023). Composite patterns, derived by averaging 24 years of data for each location, revealed higher Chl-a concentrations in western Lake Erie and along the shorelines, with a decline towards the center of the lake. Chl-a concentration typically peaked in August or September during the HABs-prone period from June to October, with the timing varying by location. Furthermore, long-term trends at each location, assessed using the Mann-Kendall test, indicated an increasing trend in 34.43 % of the lake area and no trend in 65.51 %. The areas with increasing trends were primarily concentrated in the central and western regions of Lake Erie. Based on Chl-a levels and trends, we identified and classified nine Chl-a regimes across the lake. Each regime is characterized by distinct Chl-a levels and varied long-term trends, which differ from those observed in-situ measurements and from the average patterns seen across the entire lake. These findings provide a comprehensive understanding of the long-term spatiotemporal dynamics of Chl-a in Lake Erie, while emphasizing local Chl-a heterogeneity. Moreover, the long-term Chl-a analysis and regime classification can guide decision-making, supporting the prioritization of Chl-a management areas and the expansion of monitoring networks.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"148 ","pages":"Article 102896"},"PeriodicalIF":5.5,"publicationDate":"2025-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144196011","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":"Integrated physiological and transcriptomic analysis reveals mechanism of planktonic dinoflagellate Gymnodinium catenatum response to heat and cold stress","authors":"Jingyuan Shi ,&nbsp;Yun Liu ,&nbsp;Beining Xue ,&nbsp;Yanshuo Liang ,&nbsp;Shuqun Song ,&nbsp;Haifeng Gu ,&nbsp;Caiwen Li","doi":"10.1016/j.hal.2025.102884","DOIUrl":"10.1016/j.hal.2025.102884","url":null,"abstract":"<div><div>The paralytic shellfish toxin-producing dinoflagellate <em>Gymnodinium catenatum</em> is distributed worldwide and often forms massive blooms in coastal waters, which pose a major threat to economic development and human safety. Temperature is among the factors influencing the growth and toxin production of HABs species. However, the physiological and molecular responses of <em>G. catenatum</em> to cold and heat stress need more investigations. Here, we compared the growth, toxin production, and transcriptomes of <em>G. catenatum</em> (Xiamen Bay, China) at different temperatures. Both cold (15°C) and heat (30°C) stress suppressed the growth and chlorophyll <em>a</em> content of <em>G. catenatum</em>. Transcriptomic analysis revealed that carbon from growth-related processes was redirected toward fatty acid synthesis to enhance energy storage under cold stress; up-regulated cold shock proteins and RNA-binding proteins maintained the stability of nucleic acids. Antioxidant activity was enhanced under heat stress with energy and carbon skeletons derived from the light reaction and starch and leucine degradation. The increase in toxin production probably stemmed from the enhanced transcription of core toxin synthesis genes and the inhibition of cell division under cold stress, whereas heat stress markedly enhanced the expression of genes involved in toxin synthesis. This enhanced the ability of <em>G. catenatum</em> to survive over a range of temperatures, and the increased frequency and toxicity of its blooms have significant ecological and economic implications under future global warming.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"147 ","pages":"Article 102884"},"PeriodicalIF":5.5,"publicationDate":"2025-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143928916","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":"Toxicity and toxin profile of La Réunion (Indian Ocean) fish containing CTX-like compounds","authors":"Lourdes Barreiro-Crespo ,&nbsp;Andres Sanchez-Henao ,&nbsp;Sandra Gimeno-Monforte ,&nbsp;Jaume Reverté ,&nbsp;Mònica Campàs ,&nbsp;Takeshi Tsumuraya ,&nbsp;Jorge Diogène ,&nbsp;Alina Tunin-Ley ,&nbsp;Fanny Maillot ,&nbsp;Cintia Flores ,&nbsp;Núria Fontanals ,&nbsp;Francesc Borrull ,&nbsp;Jean Turquet ,&nbsp;Maria Rambla-Alegre","doi":"10.1016/j.hal.2025.102882","DOIUrl":"10.1016/j.hal.2025.102882","url":null,"abstract":"<div><div>Several outbreaks of ciguatera poisoning have been recorded in La Réunion (SW Indian Ocean) since 1986. Toxicities and toxin profiles of fish from the Indian Ocean are poorly documented. In this work, a multidisciplinary study on the toxicity of fish from the Indian Ocean by neuro-2a cell-based assay was assessed, and the CTX-like compounds were evaluated by a magnetic bead-based immunoassay. The toxin profile is described by liquid chromatography coupled to tandem mass spectrometry and high-resolution mass spectrometry. The liver, muscle, and viscera of four fish specimens of three different species (one <em>Lutjanus bohar</em>, two <em>Variola louti</em> and one <em>Carcharinus leucas</em>) caught in the waters of La Réunion were analysed. One of the <em>V. louti</em> specimens was obtained after a CP incident. Their toxicity values ranged between 0.01 and 2.69 μg CTX1B equiv.·kg^-1 in flesh, 1.60 and 6.50 μg CTX1B equiv.·kg^-1 in liver and 0.07 and 4.77 μg CTX1B equiv.·kg^-1 in viscera. In general, liver and viscera showed higher concentrations of CTX-like compounds than flesh. Several potential CTX congeners were identified. LC-MS/MS confirmed the presence of CTX1B, 52-<em>epi</em>-54-deoxyCTX1B and 54-deoxyCTX1B in the flesh of the <em>V. louti</em> specimen involved in the CP incident. CTX1B was identified in the three tissues of the other <em>V. louti</em> individual and in the <em>L. bohar</em>. The <em>C. leucas</em> samples revealed the presence of a complex CTXs profile showing congeners of the CTX3C-group. The strategy used within this research work could be a valuable tool for future food safety monitoring in the Indian Ocean area.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"147 ","pages":"Article 102882"},"PeriodicalIF":5.5,"publicationDate":"2025-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143941942","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":"Blooming in the Anthropocene: Perspectives on the development of freshwater blooms, changing phytoplankton communities, and mitigation strategies","authors":"Tatiana E. Gámez ,&nbsp;Schonna R. Manning","doi":"10.1016/j.hal.2025.102883","DOIUrl":"10.1016/j.hal.2025.102883","url":null,"abstract":"<div><div>Freshwater is a declining natural resource sensitive to anthropogenic impacts on the environment, now exacerbated by climate change and elevated global temperatures. Among modern predicaments associated with the Anthropocene are nuisance and harmful algal blooms (HABs), which typically correlate with eutrophication resulting in the rapid growth and overabundance of planktonic microalgae, including cyanobacteria. Regions of hypoxia are common following bloom collapse, and some species of microalgae produce potent toxins, intensifying environmental impacts. While there has been some success implementing mitigation strategies against common bloom-forming microalgae, their responses to treatments are inconsistent. Routine mitigation can be incredibly costly while not being entirely effective, warranting innovation in mitigation strategies. Ultimately, a significant reduction in nutrient loading has the greatest potential for successful mitigation yet is not feasible due to societal requirements. At present, eutrophication and water pollution associated with bloom events are treated on a case-by-case basis, which can be unique depending on the microalgae present. This review provides a comprehensive summary of nuisance and harmful bloom-forming taxa, driving environmental factors, and existing mitigation strategies unique to freshwater microalgae. The major groups of bloom-forming microalgae are discussed, integrating factors responsible for increasing blooms in a rapidly changing climate, including potential treatment strategies.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"147 ","pages":"Article 102883"},"PeriodicalIF":5.5,"publicationDate":"2025-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143928915","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":"Transcriptomic comparison unveils saxitoxin biosynthesis genes in the marine dinoflagellate Gymnodinium catenatum","authors":"Buhari Lawan Muhammad ,&nbsp;Han-Sol Kim ,&nbsp;Quynh Thi Nhu Bui ,&nbsp;Jang-Seu Ki","doi":"10.1016/j.hal.2025.102872","DOIUrl":"10.1016/j.hal.2025.102872","url":null,"abstract":"<div><div>The marine dinoflagellate <em>Gymnodinium catenatum</em> is known to produce saxitoxins (STXs) that are responsible for paralytic shellfish poisoning (PSP); however, the genes involved in STX synthesis are insufficiently understood. In the present study, we determined transcriptome sequences of toxic <em>G. catenatum</em> isolated from Korea (Gc-KR) and compared them with <em>G. catenatum</em> strains reported in other regions such as Spain (Gc-SP) and the United States (Gc-US). Toxin analysis showed that the Korean strain produced the toxins at 6.0 ± 1.9 STXs eq fmol/cell. Comparative transcriptomics of the three strains identified more than 1000 homologs of nearly all STXs biosynthesis genes in dinoflagellates, except <em>sxtB, sxtN</em>, and <em>sxtY</em>. Gene expression analysis revealed similar <em>sxt</em> expression patterns across all strains, with the highest expression levels observed for <em>sxtA</em> and <em>sxtG</em>. Phylogenetic analysis of <em>sxtA, sxtG, sxtI, sxtU</em>, and <em>sxtS</em> revealed distinct evolutionary patterns, with <em>sxtA</em> being more conserved across <em>G. catenatum, Alexandrium</em> spp., and toxic cyanobacteria, particularly at the <em>sxtA4</em> domain, suggesting its significance in STXs synthesis. Other <em>sxt</em> genes in <em>G. catenatum</em> showed distinct patterns and significant divergence from <em>Alexandrium</em> spp., suggesting independent acquisition in <em>G. catenatum</em>. Moreover, the absence of core genes, such as <em>sxtB</em>, indicates it may not be essential for STXs production in <em>G. catenatum</em>. These findings provide insight into the <em>sxt</em> candidate genes in <em>G. catenatum</em>, enhancing our understanding of STXs biosynthesis in dinoflagellates.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"147 ","pages":"Article 102872"},"PeriodicalIF":5.5,"publicationDate":"2025-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143906502","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":"Toxin uptake and slowed reflexes by the marine snail Lunella undulata following exposure to paralytic shellfish toxin producing Alexandrium catenella","authors":"Andreas Seger ,&nbsp;James Brady ,&nbsp;Kellen S. Vandeveer ,&nbsp;Timothy Jordan ,&nbsp;Andrew J. Trotter ,&nbsp;Grace Robinson ,&nbsp;John J. Keane ,&nbsp;Alison Turnbull","doi":"10.1016/j.hal.2025.102868","DOIUrl":"10.1016/j.hal.2025.102868","url":null,"abstract":"<div><div>Comparatively little is known about paralytic shellfish toxin (PST) accumulation by marine grazers, yet recurrent blooms of <em>Alexandrium catenella</em> have caused repeated closures of wild fisheries and require ongoing monitoring. To determine if the commercially harvested periwinkle <em>Lunella undulata</em> is at risk of PST uptake, a laboratory experiment was conducted exposing the herbivorous/detritovorous marine snails to either live or senescent <em>Alexandrium catenella</em> microalgae. After 21 days of exposure, the highest PST concentrations were observed in the viscera of animals in the senescent and live algal treatments (0.55±0.08 and 0.82±0.12 mg STX.2HCl eq./kg, respectively). No quantifiable PST was observed in the foot of animals from either exposure treatment. The PST profile in the viscera closely matched that of the microalgal source, suggesting PST uptake through direct grazing of <em>L. undulata</em> on vegetative <em>A. catenella</em> cells. Grazing activity remained unchanged throughout the exposure period across all treatments. However, periwinkles exposed to <em>A. catenella</em> were significantly slower to retract their foot in response to touch than those animals in the control treatment (first observed on days 7 and 11 in the dead and live algae treatments, respectively). This effect became more pronounced over time and coincided with higher PST concentrations. While righting speed did not differ between animals exposed to live microalgae and the control, those exposed to senescent algae were generally slower to right (observed from day 4 onwards). The implications of these findings for biotoxin management in periwinkles and related marine grazers are discussed.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"147 ","pages":"Article 102868"},"PeriodicalIF":5.5,"publicationDate":"2025-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143906571","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 decade-long study on harmful dinoflagellate blooms and biotoxin contamination in mussels from the north-western Adriatic Sea (Mediterranean Sea)","authors":"Giorgia Zoffoli ,&nbsp;Laura Pezzolesi ,&nbsp;Mara Simonazzi ,&nbsp;Franca Guerrini ,&nbsp;Silvana Vanucci ,&nbsp;Anna Calfapietra ,&nbsp;Sonia Dall’Ara ,&nbsp;Irene Servadei ,&nbsp;Rossella Pistocchi","doi":"10.1016/j.hal.2025.102870","DOIUrl":"10.1016/j.hal.2025.102870","url":null,"abstract":"<div><div>The north-western Adriatic Sea is one of the most eutrophic areas of the Mediterranean Sea and an important aquaculture region, accounting for about 90% of Italian shellfish production. Since the 1970s, this area has experienced frequent harmful algal blooms, posing risks to consumers and coastal ecosystems. Despite the regular monitoring required by European legislation, long-term studies integrating taxonomic analysis of phytoplankton species, associated biotoxins, and environmental data remain limited. This study examines an 11-year dataset (2012–2022) from the Emilia-Romagna region coast, focusing on timing and occurrence trends of toxic dinoflagellates related to the shellfish toxicity. Phytoplankton species distribution and biotoxins content in farmed mussels were analysed, with particular attention to the presence of analogues. From 2012 to 2015, the most prevalent toxins were yessotoxins (YTXs, up to 8.44 mg kg^-1), primarily homo-YTX and 45OH homo-YTX, which were associated with autumn blooms of <em>Gonyaulax spinifera</em> and <em>Lingulaulax polyedra</em>. From 2015, okadaic acids and derivatives (OAs, up to 941 µg kg^-1) became the most prevalent phycotoxin group, associated to <em>Dinophysis fortii</em> and <em>Dinophysis acuminata</em> presence during autumn. This temporal shift was likely driven by increasing surface water temperature and salinity, which contributed to reduced water column mixing favouring oligotrophic species. Notably, low levels of YTXs persisted in mussels despite decreased abundances of producing species. Additionally, <em>Alexandrium</em> spp. cells were consistently detected, even in the absence of saxitoxins (STXs) in bivalves. These findings highlighted the need for integrated studies on strain-specific toxicity, phycotoxins accumulation in bivalves, and field monitoring.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"146 ","pages":"Article 102870"},"PeriodicalIF":5.5,"publicationDate":"2025-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143913124","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":"Analysis of ciguatoxins in fish with a single-step sandwich immunoassay","authors":"Jaume Reverté ,&nbsp;Shivangi Shukla ,&nbsp;Takeshi Tsumuraya ,&nbsp;Masahiro Hirama ,&nbsp;Jean Turquet ,&nbsp;Jorge Diogène ,&nbsp;Mònica Campàs","doi":"10.1016/j.hal.2025.102869","DOIUrl":"10.1016/j.hal.2025.102869","url":null,"abstract":"<div><div>Ciguatoxins (CTXs) are the primary cause of ciguatera poisoning (CP), one of the most prevalent non-bacterial seafood-borne illnesses worldwide. With no cure available beyond palliative treatments to alleviate symptoms, effective CP management relies on prevention. However, the detection of CTXs in seafood poses significant analytical challenges due to their typically low concentrations in specimens and the high variability among CTX congeners, many of which remain poorly characterized. These challenges have led to a growing demand for the development of rapid, sensitive, and user-friendly bioanalytical tools for CP surveillance. In this study, several simplified sandwich immunoassay strategies were evaluated for the detection of Pacific CTXs in fish. Among them, the single-step strategy was identified as the most promising, as it enables the detection of Pacific CTXs in complex fish matrixes within only 40 min at levels as low as 0.01 µg CTX1B equivalents/kg of fish, aligned with the safety guidance level proposed by the United States Food and Drug Administration (FDA). Unlike traditional sandwich immunoassays, which require several sequential incubation steps, the single-step strategy involves a simultaneous incubation of all components with the sample, uniquely followed by a washing and substrate incubation step prior to signal measurement. This approach significantly reduces both the complexity and time required for analysis, positioning this immunoassay as a highly promising tool for CP risk assessment and management.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"146 ","pages":"Article 102869"},"PeriodicalIF":5.5,"publicationDate":"2025-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143899590","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 and salinity affect growth and toxin content of cyanobacterium Microcystis aeruginosa (PCC 7806) in estuarine environments","authors":"Wenxin Liu,&nbsp;Ilias Semmouri,&nbsp;Suzanne Bulckaert,&nbsp;Colin R. Janssen,&nbsp;Jana Asselman","doi":"10.1016/j.hal.2025.102871","DOIUrl":"10.1016/j.hal.2025.102871","url":null,"abstract":"<div><div><em>Microcystis aeruginosa</em> is considered a harmful cyanobacterial species due to its ability to produce microcystins (MCs) and its increasing prevalence in estuarine environments. While previous studies have demonstrated the effects of individual environmental factors on either growth or toxin content of <em>M. aeruginosa</em>, potential interactive effects and resulting changes in its toxicity remain unclear. In this study, we first conducted an orthogonally designed growth experiment to assess potential effects of changes in temperature, salinity, pH, and nutrient conditions. Subsequently, we performed a full-factorial growth experiment focusing on temperature and salinity as key variables. Intracellular and extracellular MCs content, as well as phycocyanin levels, were measured during both exponential and stationary growth phases. Toxicity was further evaluated based on mortality and swimming behavior of the epibenthic copepod <em>Nitokra spinipes</em> and the planktonic copepod <em>Acartia tonsa</em>. Results showed that both growth rate and MCs content significantly increased with temperature (from 15 to 28 °C) but decreased with higher salinity (from 8 to 16 ppt). Moreover, cell density was significantly correlated with both intracellular and extracellular MCs contents. A significant interaction between temperature and salinity was observed. No correlation was found between intracellular MCs and phycocyanin contents. Finally, exposure to <em>M. aeruginosa</em> resulted in decreased swimming speed, increased inactivity, and higher mortality in <em>A. tonsa,</em> compared to the non-toxic <em>Rhodomonas salina</em>. Our study highlights the consequences of temperature and salinity on <em>M. aeruginosa</em> growth and toxin production, offering increased insights into the potential ecotoxicological risks of future blooms.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"146 ","pages":"Article 102871"},"PeriodicalIF":5.5,"publicationDate":"2025-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143899589","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}