Harmful Algae最新文献

{"title":"Sailing together: A review of the pelagic Sargassum microbiome","authors":"D.D. Cox ,&nbsp;A.K. Stiffler ,&nbsp;V. Hervé ,&nbsp;M. Léger-Pigout ,&nbsp;L.C. Powers ,&nbsp;P.J. Lopez ,&nbsp;O.A. Sosa ,&nbsp;R.J. Parsons","doi":"10.1016/j.hal.2025.102904","DOIUrl":"10.1016/j.hal.2025.102904","url":null,"abstract":"<div><div>Pelagic <em>Sargassum</em>, denoting the two species <em>S. natans</em> and <em>S. fluitans</em>, has become a focal point of both scientific and public interest due to recent superbloom events. As a result, investigation into the dynamics of <em>Sargassum</em>-associated microbiota, which was previously quite limited, has regained momentum in the past five years. This review collates the current state of knowledge relating to the <em>Sargassum</em> microbiome as well as synthesizes relevant biogeochemical findings which may aid future efforts in this field. We explore microbiome composition and functional roles within this holobiont, specifically in terms of taxonomic diversity, macronutrient cycling, and the fate of <em>Sargassum</em>-derived organic matter. Despite progress, significant gaps remain in our understanding of the dynamic interactions within these microbial communities and their broader ecological significance. Future research directions are identified alongside recommendations for standardized protocols, emphasizing the need for more in-depth studies utilizing advanced molecular and biogeochemical techniques to unravel the full complexity of the <em>Sargassum</em> microbiome.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"148 ","pages":"Article 102904"},"PeriodicalIF":5.5,"publicationDate":"2025-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144518941","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":"History, current status and future perspectives of sargassum management in the Eastern Caribbean SIDS: A story from the frontline","authors":"Kristie S.T. Alleyne ,&nbsp;Richéda Speede ,&nbsp;Hazel A. Oxenford ,&nbsp;Patrick McConney","doi":"10.1016/j.hal.2025.102910","DOIUrl":"10.1016/j.hal.2025.102910","url":null,"abstract":"<div><div>Mass influxes of pelagic <em>Sargassum</em> spp. in the Wider Caribbean region, since their inception in 2011, continue to present authorities with unprecedented management challenges relating to clean up, disposal and development of possible uses. To address these challenges, there have been many initiatives aimed at enhancing national capacity for the management of sargassum inundations and improving adaptation to influx events, and numerous technical and academic papers published on this topic. However, literature with specific relevance to the Eastern Caribbean Small Island Developing States (EC SIDS) is limited and somewhat fragmented. In this narrative review of the Eastern Caribbean sargassum management literature, together with our own knowledge and experience in this area, we examine the timeline of sargassum management, the current status of management, and highlight research and policy gaps that need to be addressed to improve management. In so doing we document how small island countries within the Eastern Caribbean have transitioned from simply reacting to sargassum influx events as a hazard, towards long-term adaptation and offer our perspectives on future management of sargassum in these SIDS. Throughout the years, the EC SIDS have excelled in knowledge dissemination, networking, research and securing some financial support, however, progress with implementation of management plans and improving institutional capacity has been comparatively slow. Advancing sustainable sargassum management in this region will require stronger governance, improved coordination, and sustained investment from both national governments and regional intergovernmental bodies. The key lessons from this review are likely to be highly relevant to other SIDS across the globe that are facing macroalgal blooms with similar resource and governance constraints.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"148 ","pages":"Article 102910"},"PeriodicalIF":5.5,"publicationDate":"2025-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144306322","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":"Ocean acidification changes the interspecific competition of Sargassum fusiforme and Ulva lactuca by regulating carbon and nitrogen metabolism","authors":"Cong Cao ,&nbsp;Dongya Bao ,&nbsp;Lili Xu ,&nbsp;Zengling Ma ,&nbsp;Mingjiang Wu ,&nbsp;Guang Gao ,&nbsp;Kit Wayne Chew ,&nbsp;Shuaipeng Tian ,&nbsp;Binbin Chen","doi":"10.1016/j.hal.2025.102908","DOIUrl":"10.1016/j.hal.2025.102908","url":null,"abstract":"<div><div>Due to different response mechanisms of cultivated <em>Sargassum fusiforme</em> and its main epiphyte <em>Ulva lactuca</em> to ocean acidification caused by increased CO₂ concentrations, the effects of <em>U. lactuca</em> on its host may be different at elevated CO₂ concentrations. In this study, the effects of <em>U. lactuca</em> on the photosynthetic carbon assimilation process of <em>S. fusiforme</em> were studied under the condition of elevated CO₂ concentration. The results showed that co-culture with <em>U. lactuca</em> significantly inhibited the growth, photosynthesis and nitrogen metabolism of <em>S. fusiforme</em>, up-regulated the expression of its carbon assimilation-related genes such as antenna protein, phosphoglycerate kinase (PGK), ribulose-1,5-diphosphate carboxylase/oxygenase (RuBisCo), and down-regulated the expression of genes associated with growth and nitrogen metabolism. Under monoculture conditions, the growth and photosynthesis of <em>S. fusiforme</em> were significantly enhanced by elevated CO₂, and the expressions of photosynthetic carbon assimilation and antenna protein-related genes were up-regulated, reflecting the promotion of <em>S. fusiforme</em> photosynthesis. However, the enzyme activity and gene expression of nitrogen metabolism were inhibited. Under co-culture condition, the increase of CO₂ concentration also promoted the photosynthesis and growth of <em>S. fusiforme</em>, and up-regulated the expression of genes related to photosystem Ⅱ (PSⅡ) central proteins (including D1 and D2 proteins). The results of this study showed that <em>U. lactuca</em> inhibited the photosynthesis, growth and nitrogen metabolism of <em>S. fusiforme</em>, while ocean acidification promoted the photosynthesis of <em>S. fusiforme</em> by increasing activity of PSII, changing the carbon and nitrogen metabolism strategy, thus greatly alleviating the interspecific stress from its epiphyte <em>U. lactuca</em>. These results had important implications for exploring the ecological significance of seaweed farming and carbon sequestration efficiency in the context of future climate change.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"148 ","pages":"Article 102908"},"PeriodicalIF":5.5,"publicationDate":"2025-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144254428","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":"Molecular techniques for understanding harmful algal blooms: A review","authors":"Jackson Sanders,&nbsp;Senjie Lin","doi":"10.1016/j.hal.2025.102909","DOIUrl":"10.1016/j.hal.2025.102909","url":null,"abstract":"<div><div>Harmful algal blooms (HABs) are intricate ecological events caused by diverse algal species and are influenced by a myriad of biotic and abiotic factors. The urgently needed development of effective prevention and control techniques face two primary challenges. The first challenge is the technical shortfalls in rapidly identifying and monitoring the causative species. The second challenge is the absence of research frameworks and technologies for accurately diagnosing the primary drivers of these blooms. Molecular techniques offer promising solutions to these issues, and research in this field has seen significant growth over the past two decades. Previous reviews have predominantly focused on species identification and monitoring, leaving the status of bloom driver studies less clear. This review provides a comprehensive overview of molecular techniques for HAB identification and driver analysis. HAB-specific use cases of techniques and comparison between them based on technical specifications are provided. Nucleic acid-based techniques presently dominate over antibody-based techniques due to their tunable taxon-specificity and ease to prepare probes. In situ applications and monitoring platforms still have a large room for improvement. The omics approach is the most promising choice for unraveling HAB drivers but requires a framework and a quantitative model for estimating the contribution of potential responsible factors. Future prospects relating to particular needs in HAB research and emerging technologies are also discussed.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"148 ","pages":"Article 102909"},"PeriodicalIF":5.5,"publicationDate":"2025-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144242743","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":"Deciphering the response mechanism of microorganisms to green tide outbreaks: Diversity, assembly processes, and co-occurrence patterns","authors":"Yurou Jiang ,&nbsp;Wangxinze Shu ,&nbsp;Furong Cao ,&nbsp;Jiyuan Wan ,&nbsp;Tianjing Shi ,&nbsp;Qian Liu ,&nbsp;Mingjian Liu ,&nbsp;Yong Jiang","doi":"10.1016/j.hal.2025.102907","DOIUrl":"10.1016/j.hal.2025.102907","url":null,"abstract":"<div><div>Green tide, a widespread coastal water environmental issue, significantly impacts the ecology of nearshore microorganisms. Despite extensive research on green tides, the dynamics of microbial communities and their assembly mechanisms throughout the development of these events are still not well understood. To elucidate these responses and underlying mechanisms, we conducted a comprehensive study examining the diversity, composition, and ecological dynamics of prokaryotic and microeukaryotic communities at various phases of green tide events by integrating high-throughput sequencing. The results revealed that deterministic processes predominated prokaryotic community assembly during green tide events, transitioning to stochastic processes in the post-bloom phase, while the assembly of microeukaryotic communities was consistently driven by deterministic processes at all phases. Co-occurrence network analysis indicated that green tide outbreaks reduced the connectivity and modularity of microbial networks, thereby weakening their overall stability. Functional predictions suggest that green tides may influence methane oxidation and inhibit nitrogen fixation, while simultaneously enhancing nitrification and denitrification processes. These changes could potentially alter the carbon and nitrogen cycles in coastal ecosystems. Additionally, we observed an increase in the abundance of the <em>dddL</em> gene, which may promote the production of dimethyl sulfide (DMS) and thus impact the atmospheric sulfur cycle. Furthermore, the outbreaks of green tides appear to facilitate phosphorus synthesis and iron oxidation. Overall, this study provides a foundational microbial dataset and novel insights into the dynamics of microbial networks during green tide events. These findings offer a better understanding of the microbial community's response to green tides and their potential impacts on biogeochemical cycles in coastal ecosystems.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"148 ","pages":"Article 102907"},"PeriodicalIF":5.5,"publicationDate":"2025-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144212671","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":"Genomic and phylogenetic analyses of the domoic acid biosynthesis genes in the benthic diatom Nitzschia navis-varingica (Bacillariophyceae)","authors":"Zongmei Cui ,&nbsp;Hui Wang ,&nbsp;Po Teen Lim ,&nbsp;Suh Nih Tan ,&nbsp;Yuichi Kotaki ,&nbsp;Chui Pin Leaw ,&nbsp;Nansheng Chen","doi":"10.1016/j.hal.2025.102905","DOIUrl":"10.1016/j.hal.2025.102905","url":null,"abstract":"<div><div>Through genome sequencing and comparative genomic analysis, candidate genes involved in the biosynthesis of domoic acid (DA) in the benthic diatom <em>Nitzschia navis-varingica</em> were identified. Orthologs of DA biosynthesis genes (<em>dabA, dabB, dabC</em>, and <em>dabD</em>), originally identified in <em>Pseudo-nitzschia</em> species, were detected in <em>N. navis-varingica</em> strains. However, due to the draft level of our genomes, the tandem gene cluster organization present in the <em>Pseudo-nitzschia</em> species cannot be determined in <em>N. navis-varingica</em> strains. In addition, two copies of <em>dabC</em> were found in <em>N. navis-varingica</em> strains, suggesting potential functional significance in the biosynthesis of DA and its isoforms. The identification of <em>dab</em> genes in <em>N. navis-varingica</em> provides a foundation for further studies on the origin, evolution, and transcriptional regulations of DA biosynthesis in this benthic diatom.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"148 ","pages":"Article 102905"},"PeriodicalIF":5.5,"publicationDate":"2025-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144189506","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":"Context-dependent allelopathy in algal interactions: Insights from laboratory and natural phytoplankton communities","authors":"Kristy S. Syhapanha ,&nbsp;Remington X. Poulin ,&nbsp;David A. Russo ,&nbsp;Wesley Yee Fei Wong ,&nbsp;Georg Pohnert","doi":"10.1016/j.hal.2025.102886","DOIUrl":"10.1016/j.hal.2025.102886","url":null,"abstract":"<div><div>A key aspect of algal biology is the production of chemicals used for communication and regulation of interactions. Allelopathic chemicals can facilitate competition between algae, influence community composition and drive succession in the phytoplankton. Much is still unknown about the identities of these allelochemicals, and even the ecological relevance of laboratory derived results is often unclear. We sought to evaluate the variability of allelopathy employing a systematic approach. We used <em>Prymnesium parvum</em> as a model to assess species-specificity of allelopathic interactions in laboratory co-cultivations. We assessed the influence of media, ratio of cell densities of the interaction partners and evaluation methods (monitoring of chlorophyll <em>a</em> versus cell density) on the outcome of co-cultivation experiments. Five tested ecologically relevant phytoplankton species, <em>Dunaliella tertiolecta, Emiliania</em> (presently <em>Gephyrocapsa</em>) <em>huxleyi, Florenciella parvula, Ochromonas triangulata</em>, and <em>Pavlova gyrans,</em> exhibited and experienced varying positive and negative allelopathic effects in interactions with <em>P. parvum</em>. Further, we document pronounced effects of variations of laboratory parameters. Among the ten possible bidirectional allelopathic relationships, half of the allelopathic effects were changed by one or more of the variable parameters tested. Allelopathy is thus not only a species-specific trait but additionally depends on the external factors present during the interactions. We support our findings through the identification of interaction patterns from mining the Tara Oceans database for reoccurring trends in natural and laboratory communities. This study strongly supports the notion that allelopathic activity of an alga is not only a species-specific property but also depends on many external parameters that have to be considered and thoroughly documented in future studies of allelopathy.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"148 ","pages":"Article 102886"},"PeriodicalIF":5.5,"publicationDate":"2025-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144204774","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 enhancement of harmful dinoflagellate Prorocentrum cordatum by bacterial community shifts driven by dissolved organic matter derived from raphidophyte Heterosigma akashiwo","authors":"Royoung Park ,&nbsp;Joo-Hwan Kim ,&nbsp;Jin Ho Kim ,&nbsp;Sae-Hee Kim ,&nbsp;Hyeon Ho Shin ,&nbsp;Myung-Soo Han ,&nbsp;Bum Soo Park","doi":"10.1016/j.hal.2025.102895","DOIUrl":"10.1016/j.hal.2025.102895","url":null,"abstract":"<div><div>Phytoplankton blooms release dissolved organic matter (DOM), altering the composition of marine environments, which impacts microbial communities. Variation in DOM utilization among bacterial taxa can shift bacterial community structure, potentially affecting phytoplankton growth and species composition. Given the observed bloom successions of <em>Heterosigma akashiwo</em> and <em>Prorocentrum cordatum</em>, we hypothesized that <em>H. akashiwo</em>-derived DOM could influence <em>P. cordatum</em> growth via alterations in the bacterial community. This study investigated how DOM-modified bacterial communities affect <em>P. cordatum</em> growth. Our results showed that <em>P. cordatum</em> growth was enhanced by 76–220 % when exposed to DOM-altered bacterial communities, while <em>Skeletonema costatum</em> growth was suppressed by 24–28 %. This study demonstrates that the ratio of humic-like carbon to fulvic-like carbon in <em>H. akashiwo</em>-derived DOM, particularly during the stationary and decline phases, promotes bacterial taxa capable of degrading high-molecular-weight compounds, thereby facilitating <em>P. cordatum</em> growth. Functional predictions identified specific bacterial taxa with potential growth-promoting effects. Among them, <em>Dokdonia</em>, a genus within the family Flavobacteriaceae, was enriched in DOM-exposed bacterial communities and associated with growth enhancement, whereas algicidal and methanotrophic bacteria were more abundant in the absence of DOM. These findings highlight the role of bloom-phase-specific DOM in shaping bacterial communities and driving phytoplankton bloom succession.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"148 ","pages":"Article 102895"},"PeriodicalIF":5.5,"publicationDate":"2025-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144212670","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":"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}