Harmful Algae最新文献

{"title":"Walruses are potentially exposed to paralytic shellfish toxin concentrations that impact their health during Alexandrium blooms in the Alaskan Arctic","authors":"Patrick Charapata ,&nbsp;Evangeline Fachon ,&nbsp;Donald M. Anderson ,&nbsp;Gay Sheffield ,&nbsp;Emily K. Bowers ,&nbsp;Robert S. Pickart ,&nbsp;Peigen Lin ,&nbsp;Kathi A. Lefebvre","doi":"10.1016/j.hal.2025.102960","DOIUrl":"10.1016/j.hal.2025.102960","url":null,"abstract":"<div><div>Harmful algal bloom (HAB) activity of <em>Alexandrium catenella</em>, a dinoflagellate that produces paralytic shellfish toxins (PSTs), has increased in the Alaskan Arctic due to warming ocean conditions. Arctic wildlife exposure to PSTs due to these blooms remains unknown. The Pacific walrus (<em>Odobenus rosmarus divergens</em>) is a marine mammal that preys primarily on efficient vectors of PSTs (benthic invertebrates), making walruses an important model for assessing PST exposure risks. Here, we used paired <em>Alexandrium</em> data (<em>Alexandrium</em> cell and cyst densities and PST content), and PSTs measured in benthic invertebrates (clams, worms, and gastropods) to construct and validate trophic transfer models of PSTs in a critical Arctic food chain. Further, we used observed PSTs in walrus prey to estimate daily walrus oral PST doses (µg STX eq. kg^-1) during summers (2019 and 2022) with well-characterized and widespread <em>Alexandrium</em> blooms. Models were validated using various model metrics, however, predictions underestimated toxicity (STX eq.) of invertebrates. Observed PSTs in walrus prey resulted in 89 % (<em>n</em> <em>=</em> 47 of 53 total; 2019) and 67 % (<em>n</em> <em>=</em> 41 of 61; 2022) of PST doses exceeding thresholds posing a moderate health risk to walruses (&gt; 11.6 μg STX eq. kg^-1). Ledyard Bay in the northeastern Chukchi Sea was identified as a PST exposure risk hotspot because it contained the highest estimated doses, while walruses simultaneously occupied the neighboring Point Lay haulout. Additional studies are required to assess how HAB activity will impact walrus health as well as food-security and food-safety for Indigenous communities that rely on walruses for subsistence.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"149 ","pages":"Article 102960"},"PeriodicalIF":4.5,"publicationDate":"2025-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144912872","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":"Climate change will boost the invasion of the harmful cyanobacterium Raphidiopsis raciborskii in South America","authors":"Felipe Morais Zanon ,&nbsp;Bruno Henrique Mioto Stabile ,&nbsp;Beatriz Melissa Campos ,&nbsp;Érica Oliveira de Lima ,&nbsp;Matheus Juan Alarcon Sampaio ,&nbsp;Yasmin Rodrigues de Souza ,&nbsp;Leonardo Rodrigues Tolardo ,&nbsp;Mayra Koma Gomes ,&nbsp;Luddy Searom Carias de Moraes ,&nbsp;Gabriela Sponchiado Hein ,&nbsp;Jaqueline Dantas da Silva ,&nbsp;Larissa da Silva Pinha ,&nbsp;Loiani Oliveira Santana ,&nbsp;Mariana Albuquerque ,&nbsp;Vinicius da Silva ,&nbsp;João Vitor Bredariol ,&nbsp;Gabriel Arthur Lopes da Silva ,&nbsp;Gabriel Delabio da Silva ,&nbsp;Aline Aparecida Aguiar Ferreira ,&nbsp;Luíz Fernando Esser ,&nbsp;Luzia Cleide Rodrigues","doi":"10.1016/j.hal.2025.102957","DOIUrl":"10.1016/j.hal.2025.102957","url":null,"abstract":"<div><div>The invasive cyanobacterium species <em>Raphidiopsis raciborskii</em> was first recorded in the Indo-Malaysian region in 1899, and studies currently report its presence in tropical, subtropical, and temperate environments around the world. In addition to its plasticity in colonizing new environments, <em>R. raciborskii</em> deserves attention for its ability to produce saxitoxin and cylindrospermopsin, which can cause the death of aquatic organisms and harm human health. In this work, we assessed the effect of global climate change towards the end of this century on the potential expansion of <em>R. raciborskii</em> using ecological niche models (ENMs). We applied a set of machine learning algorithms within the ensemble prediction approach to estimate the potential distribution of the species in South America under projected climate change, considering different carbon emission scenarios. In the moderate scenario, the northern Amazon basin, the southern Orinoco basin, and part of the North Atlantic basin showed increased environmental suitability for the species. In the pessimistic scenario, the basin with the greatest increase in suitability was the Paraná-Paraguay basin. Several basins remained highly suitable in both current and future scenarios, especially in Brazil. This study highlights the importance of understanding and addressing the impacts of climate change on the distribution of the invasive species <em>R. raciborskii</em>. South American countries must implement monitoring measures to assess the expansion of blooms of this species, as well as government actions to control water quality, given the strong impact of these organisms on biodiversity and ecosystem services.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"149 ","pages":"Article 102957"},"PeriodicalIF":4.5,"publicationDate":"2025-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144895575","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":"First report of nodularin production by Nostochopsis sp. in a temperate eutrophic lake","authors":"Abby M. Webster ,&nbsp;Zac Triumph ,&nbsp;Bofan Wei ,&nbsp;Robbie M. Martin ,&nbsp;Laura E. Smith ,&nbsp;Steven W. Wilhelm ,&nbsp;Lisa B. Cleckner ,&nbsp;N.Roxanna Razavi ,&nbsp;Gregory L. Boyer","doi":"10.1016/j.hal.2025.102956","DOIUrl":"10.1016/j.hal.2025.102956","url":null,"abstract":"<div><div>Benthic cyanobacteria are understudied in comparison to their planktonic counterparts. Consequently, our understanding of cyanotoxin production in benthic mats remains limited. We detected nodularin-R (NOD-R) in a population of <em>Nostochopsis</em> from Honeoye Lake (New York, United States). Identification as <em>Nostochopsis</em> was supported by morphological (see section 3.1 for a detailed description) and metagenomic analyses. The first metagenome assembled genome of <em>Nostochopsis</em> was drafted and estimated at 99.28 % complete. Cyanotoxin testing of <em>Nostochopsis</em> biomass showed production of NOD-R but not microcystins, anatoxins, or cylindrospermopsins. The complete nodularin synthetase cluster was confirmed in the <em>Nostochopsis</em> genome. To our knowledge, this is the first report of nodularin production, or any cyanotoxin production, by the benthic cyanobacteria <em>Nostochopsis</em>. This is the fourth genus of cyanobacteria reported to produce nodularins.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"149 ","pages":"Article 102956"},"PeriodicalIF":4.5,"publicationDate":"2025-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144903025","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 and regional variability of lipophilic marine phycotoxins in eutrophic coastal waters of the South China Sea","authors":"Min Liu ,&nbsp;Liyan Deng ,&nbsp;Yan Wang ,&nbsp;Xiaodong Wang ,&nbsp;Sen Du ,&nbsp;Zhicai She ,&nbsp;Zhenjun Kang ,&nbsp;Qingxia Liu ,&nbsp;Peng Wu ,&nbsp;Zexing Kuang ,&nbsp;Lingxiang Zhu ,&nbsp;Jiajun Wu ,&nbsp;Lai Leo Chan ,&nbsp;Yuanyue Cheng ,&nbsp;Li Zhang ,&nbsp;Yang Liu","doi":"10.1016/j.hal.2025.102954","DOIUrl":"10.1016/j.hal.2025.102954","url":null,"abstract":"<div><div>Lipophilic marine phycotoxins (LMTs), primarily produced by toxigenic dinoflagellates, pose significant risks to marine ecosystems and human health due to their toxicity and widespread distribution. This study investigates the spatial and temporal distribution of LMTs in the surface seawater from representative estuarine and bay areas of the South China Sea (SCS) during period from 2022‒2023. Using active solid-phase extraction coupled with liquid chromatography-tandem mass spectrometry (Active-SPE-LC-MS/MS), the study revealed that significantly higher LMTs concentrations in semi-enclosed bays (13.15 ± 8.61 ng L⁻¹) compared to estuarine regions (8.55 ± 8.59 ng L⁻¹), with Daya Bay (DB) and Jian River Estuary (JRE) exhibiting the highest toxin levels. The most prevalent toxins were diarrhetic shellfish toxins (OA, DTX1) and pectenotoxin-2 (PTX2), with PTX2 being dominant in most regions. Seasonal variations were evident, with higher LMTs concentrations observed during the wet season, particularly in spring and summer. Principal component analysis (PCA) revealed distinct toxin profiles, with PTX2, GYM, and OA being prevalent in the Pearl River Estuary (PRE), while AZA2 and DTX1 were more abundant in Qinzhou Bay (QB). The study highlights the influence of local environmental conditions, such as seasonal and region variations on LMTs distribution. These findings provide critical insights into the ecological dynamics of LMTs in eutrophic coastal waters, emphasizing the need for continuous monitoring to mitigate risks to marine ecosystems and human health. This research contributes to a deeper understanding of LMTs distribution patterns in the SCS, supporting future risk assessments and management strategies.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"149 ","pages":"Article 102954"},"PeriodicalIF":4.5,"publicationDate":"2025-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144895536","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":"Genotypic diversity and growth responses to temperature and salinity variations of Coolia malayensis (Gonyaulacales, Dinophyceae) in Chinese coastal waters","authors":"Ruoyu Guo ,&nbsp;Xu-Dong Lian ,&nbsp;Ruifang Wang ,&nbsp;Yue Jiang ,&nbsp;Sungmo Kang ,&nbsp;Chenjie Zhu ,&nbsp;Xiao Ma ,&nbsp;Shiwen Zhou ,&nbsp;Leo Lai Chan ,&nbsp;Xinfeng Dai ,&nbsp;Pengbin Wang ,&nbsp;Zhun Li","doi":"10.1016/j.hal.2025.102945","DOIUrl":"10.1016/j.hal.2025.102945","url":null,"abstract":"<div><div><em>Coolia malayensis</em> is a benthic dinoflagellate widely distributed in tropical to subtropical coastal waters, with some strains exhibiting cytotoxicity, indicating potential ecological and toxicological roles. This study investigated the genetic diversity and adaptability of <em>C. malayensis</em> strains across diverse environmental conditions in Chinese coastal waters. Three distinct genotypes, Genotype 1 (strain DF553), Genotype 2 (DF630), and Genotype 3 comprising strains DF307, DF316, and DF364, were confirmed by the large subunit (LSU) ribosomal DNA phylogenetic analysis, with a protein profiling by the matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) mass spectrometry providing supporting evidence for the phenotypic differentiations. The results of growth experiments conducted under varying temperature (15°C to 30°C) and salinity (15 to 35) conditions demonstrated genotype-specific environmental preferences: strain DF553 exhibited an optimal growth at 25°C and 30 salinity, strain DF630 at 30°C and 30, while strains DF307, DF316, and DF364 displayed a wider range of adaptive capacities. These results emphasized the ecological flexibility and adaptive potential of <em>C. malayensis</em>, indicating its ability to thrive in diverse marine environments. The study underscores the importance of genotypic variation in predicting species responses to environmental fluctuations, offering valuable insights for marine ecosystem management and mitigation of harmful algal blooms.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"149 ","pages":"Article 102945"},"PeriodicalIF":4.5,"publicationDate":"2025-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144865732","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 photodegradation fate of Brevetoxins: Kinetics, degradation pathways, and toxicity evaluation","authors":"Lianbao Chi ,&nbsp;Xiaona Zhang ,&nbsp;Yongquan Yuan ,&nbsp;Huihui Shen ,&nbsp;Zhiming Yu ,&nbsp;Xiuxian Song","doi":"10.1016/j.hal.2025.102944","DOIUrl":"10.1016/j.hal.2025.102944","url":null,"abstract":"<div><div><em>Karenia brevis</em> blooms have emerged as an increasing global concern due to their capacity to produce brevetoxins (BTXs), which are potent marine neurotoxins. The ecological impact of BTXs is significantly modulated by the natural attenuation process, with photodegradation playing a pivotal role. Nevertheless, the fate of BTXs following photodegradation remains inadequately understood. This study elucidates the photodegradation kinetics of three representative BTXs and identifies their transformation products (TPs). The observed first-order photodegradation rate coefficient, based on the logarithmic transformation of dissolved BTXs concentrations against irradiation time, ranged from 0.84 to 2.49 h^-1. Utilizing high-resolution liquid chromatography‒mass spectrometry, three, four, and five TPs were identified for BTX-1, BTX-2, and BTX-3, respectively. All TPs underwent substantial structural modifications with significant mass reductions. Proposed primary photodegradation pathways encompass Ring-opening, alkyl chain cleavage, hydrolysis, dehydroxylation, epoxidation, and β-elimination. Additionally, <em>in silico</em> prediction indicated that the biodegradability of TPs was significantly higher than that of the parent toxins. However, certain TPs exhibited greater toxicities compared to their parent toxins. The coexistence of multiple BTXs and TPs may lead to synergistic toxicity, thereby posing secondary risks to aquatic organisms. Overall, this research will enhance a comprehensive understanding of the environmental behaviors and risks associated with BTXs.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"149 ","pages":"Article 102944"},"PeriodicalIF":4.5,"publicationDate":"2025-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144903026","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":"Synergistic effects of nutrient competition, biotic interactions, and hydrological regulation drive green tide outbreaks in the South Yellow Sea","authors":"Guanbing Feng ,&nbsp;Jingfei Liu ,&nbsp;Ning Wang ,&nbsp;Lihua Xia ,&nbsp;Jiahao Fan ,&nbsp;Qingqing Mu ,&nbsp;Yuqing Sun ,&nbsp;Peiming He ,&nbsp;Jianheng Zhang","doi":"10.1016/j.hal.2025.102943","DOIUrl":"10.1016/j.hal.2025.102943","url":null,"abstract":"<div><div>Green tides serve as indicators of coastal ecosystem imbalance, yet their interannual variability and driving mechanisms remain poorly characterized. This study develops the Comprehensive Green Tide Magnitude Index (GTMI) to quantitatively classify South Yellow Sea green tide events (2008–2023) into large- and small-magnitude years. By integrating Seasonal-Trend decomposition (STL) and Random Forest Regression (RFR), we systematically decompose the trend and seasonal components of the time series while preserving its integrity, significantly enhancing the ability to interpret key environmental factors. The results identify silicate, salinity, nitrate, and sea surface temperature as key controlling factors influencing both the magnitude and periodic variability of green tide outbreaks. A partial least squares path model (PLS-PM) reveals a potential mechanism involving nutrient competition, biological interaction, and hydrological regulation. Nutrient overlap between <em>Ulva</em> and phytoplankton triggers resource exclusion, enabling <em>Ulva</em> to dominate through niche preemption and suppress phytoplankton growth, while hydrological forces amplify <em>Ulva</em> expansion and inhibitory effects. The GTMI provides a quantitative assessment tool, and the STL-RF-PLS framework advances mechanistic understanding of multifactorial drivers, offering critical insights for regional green tide mitigation and coastal ecosystem management.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"149 ","pages":"Article 102943"},"PeriodicalIF":4.5,"publicationDate":"2025-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144852956","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":"Protected high-mountain rivers harbor widespread toxic Microcoleus-dominated mats with distinct genetic profiles","authors":"Albano Diez-Chiappe,&nbsp;María Ángeles Muñoz-Martín,&nbsp;Samuel Cirés,&nbsp;Antonio Quesada,&nbsp;Elvira Perona","doi":"10.1016/j.hal.2025.102942","DOIUrl":"10.1016/j.hal.2025.102942","url":null,"abstract":"<div><div>Toxic <em>Microcoleus</em> remains poorly studied in mountain freshwaters, where cyanotoxins threaten public and ecological health, particularly in protected areas that hold high ecological value and attract a high density of visitors. This study investigated the proliferation of cyanobacterial mats and cyanotoxin production in two high-mountain rivers flowing through a National Park. Our results confirmed the widespread and recurrent proliferation of <em>Microcoleus</em>-dominated mats containing the neurotoxins anatoxin-a and homoanatoxin-a. Mat coverage showed potentially hazardous levels, reaching up to 40-50 % of the riverbed. Comprehensive genetic characterization through metabarcoding sequencing (targeting 16S rRNA and cyanotoxin-biosynthesis genes) revealed a significant differential distribution of <em>Microcoleus</em> genotypes between two adjacent high-mountain rivers, as well as the persistence of the <em>anaF</em> gene from <em>Microcoleus.</em> Although saxitoxins and microcystins were not detected, the <em>sxtA</em> gene closely related to <em>Scytonema</em> and <em>mcyE</em> from <em>Nostoc</em>-like species were occasionally found. This is the first report of abundant proliferations of anatoxin-producing <em>Microcoleus</em> in Spain, broadening research into Southern and Mediterranean Europe, where toxic <em>Microcoleus</em> remains underreported. These results reinforce the importance of genetic analyses as valuable tools for understanding <em>Microcoleus</em> population dynamics. Our findings highlight that toxic mats should be considered a potential threat in minimally impacted mountain freshwaters, especially those frequently visited for their high ecological value.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"149 ","pages":"Article 102942"},"PeriodicalIF":4.5,"publicationDate":"2025-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144841945","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":"Single-cyst morpho-molecular identification detected an unexpected high species diversity of dinoflagellate resting cysts from the coastal seas of China","authors":"Zhe Tao ,&nbsp;Yuyang Liu ,&nbsp;Xiaohan Liu ,&nbsp;Caixia Yue ,&nbsp;Xiaoying Song ,&nbsp;Zhangxi Hu ,&nbsp;Shuo Shi ,&nbsp;Ruoxi Li ,&nbsp;Yunyan Deng ,&nbsp;Lixia Shang ,&nbsp;Zhaoyang Chai ,&nbsp;Ying Zhong Tang","doi":"10.1016/j.hal.2025.102941","DOIUrl":"10.1016/j.hal.2025.102941","url":null,"abstract":"&lt;div&gt;&lt;div&gt;Over the past several decades, harmful algal blooms (HABs) caused by dinoflagellates frequently occurred along the coastal waters of China, with an increasing number of emerging HAB species. Due to the vital roles played by the resting cyst in the ecology of HABs, the investigation of resting cyst diversity and distribution of dinoflagellates, those causing HABs in particular, in marine sediment is of great significance. However, it has been difficult to unambiguously identify cyst species via obtaining both morphological and molecular evidence due to a variety of technological limitations (e.g. extremely simple morphology and/or small sizes of many cyst species). Although the application of high-throughput metabarcoding analysis has greatly improved the efficiency (high throughput) and accuracy (molecular identification) of cyst identification, lacking morphological evidence makes it less convincing because the sequences obtained with this approach may be doubted to be from fragmental vegetative cells or relics of eDNA. Furthermore, insufficient sequencing depths commonly adopted in studies using this technique together with the extremely large and widely-varying genome sizes of dinoflagellates have also led to the potential oversight of those species having small cell sizes and/or relatively low abundances. In this study, we employed a single-cyst morpho-molecular method (ScPCR sequencing) to identify dinoflagellate cysts from 23 sediments collected from all four seas of China. From 702 individually picked-up, micrographed, and sequenced cysts, we identified 127 species of dinoflagellates, with 63 (49.6%) fully identified to well-described species, and 64 (50.4%) that could not be determined for their species identity due to the unavailability of reference sequences. Notably, among the 63 fully-identified species, 6 had not been reported from China before, 19 are well-documented HABs-causing species (e.g. 8 &lt;em&gt;Alexandrium&lt;/em&gt; spp., &lt;em&gt;Gymnodinium catenatum, Karenia mikimotoi&lt;/em&gt;), and 22 were identified for the first time from one of the four seas of China. In addition, from 44 sediment samples that were collected from the East China Sea (ECS, a “hotspot” of HABs in China) and pre-processed with the sodium polytungstate protocol to concentrate their cyst assemblages, we fully identified 61 species of dinoflagellate cysts via metabarcoding analysis, including 27 species causing HABs, 10 as new records in Chinese waters, 13 as new records in the ECS, and 10 previously unreported as cyst producers. It is noteworthy that 7 (35%) of the 20 cyst species identified via ScPCR sequencing from the ECS were not detected by the metabarcoding analysis. Contrasting to that 64 species of dinoflagellate cysts had been unequivocally identified from China by 2021, the total number of cyst species identified in this study using ScPCR sequencing demonstrated the robustness of the detection technique. This study also suggests that the species diversit","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"149 ","pages":"Article 102941"},"PeriodicalIF":4.5,"publicationDate":"2025-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144828289","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":"Discovery of Fukuyoa yasumotoi (Dinophyceae) from the Xisha Islands, South China Sea: A comprehensive study on morphology, molecular phylogeny and toxicity","authors":"Ruifang Wang ,&nbsp;Wenguang Zhang ,&nbsp;Zhongyong Yan ,&nbsp;Shiwen Zhou ,&nbsp;Ruoyu Guo ,&nbsp;Junjie Zheng ,&nbsp;Xinfeng Dai ,&nbsp;Douding Lu ,&nbsp;Qinglin Mu ,&nbsp;Jiangning Zeng ,&nbsp;Mengmeng Tong ,&nbsp;Zhun Li ,&nbsp;Pengbin Wang","doi":"10.1016/j.hal.2025.102938","DOIUrl":"10.1016/j.hal.2025.102938","url":null,"abstract":"<div><div>The epiphytic dinoflagellate genus <em>Fukuyoa</em>, known for producing ciguatoxins, significantly contributes to ciguatera poisoning (CP) in humans and impacts marine food webs. This study reports the first observation and isolation of two <em>Fukuyoa</em> strains, SIO-DF176 and SIO-DF181, from the Xisha Islands in the South China Sea, both identified as <em>Fukuyoa yasumotoi</em> through morphological and molecular techniques. Molecular analysis, including assessments of small subunit (SSU) rDNA, internal transcribed spacer (ITS) rDNA, and large subunit (LSU) rDNA (D1–D3 and D8–D10 regions), revealed close relationships to strains from Japan and Singapore. The analysis of LSU rDNA regions D8–D10 did not differentiate between <em>F. yasumotoi</em> and <em>F. koreensis</em> as distinct morphospecies, underscoring the need for additional physicochemical data from both species for accurate classification. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) was employed to examine the profiles of intracellular and extracellular toxins. Strain SIO-DF176 produced 44-methylgambierone at an intracellular concentration of 10.24 pg/cell, while strain SIO-DF181 produced it at 0.59 pg/cell. Additionally, the extracellular toxin of strain SIO-DF181 comprised 44-methylgambierone at 1.34 pg/cell, whereas SIO-DF176 displayed only trace amounts of 44-methylgambierone, which did not reach the limit of quantitation. Strain SIO-DF181 produced gambierone both intracellularly and extracellularly, with concentrations of 56.22 fg/cell and 66.04 fg/cell, respectively, while strain SIO-DF176 did not produce gambierone. Notably, neither strain produced Pacific ciguatoxin (P-CTX-2 or P-CTX-3). This study highlights the presence of <em>F. yasumotoi</em> in the northwestern South China Sea and its potential CP risk.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"149 ","pages":"Article 102938"},"PeriodicalIF":4.5,"publicationDate":"2025-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144886667","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}