Harmful Algae最新文献

Efficient inhibition of Microcystis aeruginosa using expanded perlite sustained-release pyrogallic acid: performance studies, mechanistic insights and ecological security assessment 膨胀珍珠岩缓释没食子酸对铜绿微囊藻的有效抑制：性能研究、机理研究和生态安全评价

IF 4.5 1区生物学 Q1 MARINE & FRESHWATER BIOLOGY

Harmful Algae

Pub Date : 2026-05-01 Epub Date: 2026-02-26 DOI: 10.1016/j.hal.2026.103093

Yuewen Zhang , Mingjun Ma , Yujia Gao , Yu Hong , Xing Xie

Allelochemicals are effective and safe for controlling cyanobacterial blooms, but their direct application suffers from rapid degradation and poor persistence. To address this limitation, we engineered a buoyant, surface-targeting delivery system to inhibit non-toxic and toxic Microcystis aeruginosa by preparing PA/Expanded perlite composites using expanded perlite as a matrix. The results showed that PA was successfully loaded onto expanded perlite, and PA/Expanded perlite could achieve long-term release of phenolic release (PA-dominant). PA/Expanded perlite was effective in removing both non-toxic and toxic M. aeruginosa, with the maximum inhibition rate of 97.60 %, and the EC₅₀ (7d) values were 15.60 and 6.90 mg/L, respectively. The PA/Expanded perlite composite achieved a 97.62 % inhibition rate against M. aeruginosa in natural landscape water. Additionally, treatment with PA/Expanded perlite significantly reduced chlorophyll a and phycobiliprotein content in both algal strains, and the photosynthetic rates of toxic and non-toxic M. aeruginosa decreased to 0.03 and 0.0043 [μmol/(mg·h)], respectively. Meanwhile, the activities of superoxide dismutase (SOD) and catalase (CAT) and the content of malondialdehyde (MDA) were significantly increased. Under current exposure levels, PA/Expanded perlite did not pose harm to Daphnia magna and Pteris vittata, while significantly reducing intracellular microcystin-LR (MC-LR) contents, which has promising application for the control of water blooms.

化感剂是有效和安全的控制蓝藻华，但其直接应用的缺点是降解快，持久性差。为了解决这一限制，我们设计了一种浮力的表面靶向递送系统，通过制备PA/膨胀珍珠岩作为基质来抑制无毒和有毒的铜绿微囊藻。结果表明，PA被成功加载到膨胀珍珠岩上，PA/膨胀珍珠岩能够实现长时间的酚类释放（PA-显性）。PA/膨胀珍珠岩对无毒和有毒M. aeruginosa均有较好的去除效果，最大抑制率为97.60%,EC50 （7d）值分别为15.60和6.90 mg/L。PA/膨胀珍珠岩复合材料对自然景观水体中铜绿假单胞菌的抑制率为97.62%。此外，PA/膨胀珍珠岩处理显著降低了两种藻类的叶绿素a和藻胆蛋白含量，有毒和无毒铜绿假单胞菌的光合速率分别降至0.03和0.0043 [μmol/(mg·h)]。同时，超氧化物歧化酶（SOD）、过氧化氢酶（CAT）活性和丙二醛（MDA）含量显著升高。在当前暴露水平下，PA/膨胀珍珠岩对大水蚤和维塔翼虫不造成危害，但能显著降低细胞内微囊藻毒素lr （MC-LR）含量，在防治水华方面具有广阔的应用前景。

{"title":"Efficient inhibition of Microcystis aeruginosa using expanded perlite sustained-release pyrogallic acid: performance studies, mechanistic insights and ecological security assessment","authors":"Yuewen Zhang , Mingjun Ma , Yujia Gao , Yu Hong , Xing Xie","doi":"10.1016/j.hal.2026.103093","DOIUrl":"10.1016/j.hal.2026.103093","url":null,"abstract":"<div><div>Allelochemicals are effective and safe for controlling cyanobacterial blooms, but their direct application suffers from rapid degradation and poor persistence. To address this limitation, we engineered a buoyant, surface-targeting delivery system to inhibit non-toxic and toxic <em>Microcystis aeruginosa</em> by preparing PA/Expanded perlite composites using expanded perlite as a matrix. The results showed that PA was successfully loaded onto expanded perlite, and PA/Expanded perlite could achieve long-term release of phenolic release (PA-dominant). PA/Expanded perlite was effective in removing both non-toxic and toxic <em>M. aeruginosa</em>, with the maximum inhibition rate of 97.60 %, and the EC<sub>50</sub> (7d) values were 15.60 and 6.90 mg/L, respectively. The PA/Expanded perlite composite achieved a 97.62 % inhibition rate against <em>M. aeruginosa</em> in natural landscape water. Additionally, treatment with PA/Expanded perlite significantly reduced chlorophyll a and phycobiliprotein content in both algal strains, and the photosynthetic rates of toxic and non-toxic <em>M. aeruginosa</em> decreased to 0.03 and 0.0043 [μmol/(mg·h)], respectively. Meanwhile, the activities of superoxide dismutase (SOD) and catalase (CAT) and the content of malondialdehyde (MDA) were significantly increased. Under current exposure levels, PA/Expanded perlite did not pose harm to <em>Daphnia magna</em> and <em>Pteris vittata,</em> while significantly reducing intracellular microcystin-LR (MC-LR) contents, which has promising application for the control of water blooms.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"155 ","pages":"Article 103093"},"PeriodicalIF":4.5,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147388146","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}

引用次数: 0

Blooms like it hot, but mussels do not: Influence of invasive quagga mussels on cyanobacteria during summer 水华喜欢炎热，但贻贝不喜欢：夏季入侵斑驴贻贝对蓝藻的影响

IF 4.5 1区生物学 Q1 MARINE & FRESHWATER BIOLOGY

Harmful Algae

Pub Date : 2026-05-01 Epub Date: 2026-02-25 DOI: 10.1016/j.hal.2026.103094

Jonas Mauch , Maider Erize Gardoki , Raphael Neiling , Jan Köhler , Jordan Facey , Sabine Hilt

Quagga mussels (Dreissena rostriformis bugensis) are among the most impactful invaders in freshwaters of the Northern Hemisphere. As filter-feeders, they can reduce harmful algal blooms (HABs), but their effects are expected to be dependent on cyanobacteria species and water temperature. However, conclusive studies on these traits and their combination are lacking. Here, we combined laboratory experiments with an analysis of long-term data from a temperate shallow lake 10 years before and after quagga mussel invasion, respectively. We tested the hypotheses that quagga mussel filtration rates in the laboratory would 1) vary among common cyanobacteria species and 2) decrease above a critical temperature. Regarding the field data, we expected that 3) quagga mussels can reduce the summer biovolume of palatable cyanobacteria, but that 4) this effect disappears above a critical temperature. Our results support all four hypotheses. In laboratory experiments, Dolichospermum flos-aquae was classified as palatable to quagga mussels, while Aphanizomenon flos-aquae, Anabaenopsis elenkinii and Microcystis aeruginosa were less-palatable cyanobacteria. Filtration rates decreased above 28.9°C (CI: 27.6–30.2°C) with mussels dying at 32°C. Our long-term lake data show that cyanobacteria biovolumes were lower after quagga mussel invasion, but only below 27.7°C (CI: 26.9–28.4°C), confirming a critical thermal window for quagga mussel filtration. Global warming will therefore facilitate HABs by increasing the growth rates of cyanobacteria and reducing the filtration rates of quagga mussels above critical summer water temperatures, which are increasingly being reached in invaded lakes. This critical thermal window must be considered when making HAB predictions.

斑蚌（Dreissena rostriformis bugensis）是北半球淡水中最具影响力的入侵者之一。作为滤食性动物，它们可以减少有害藻华（HABs），但它们的效果预计取决于蓝藻种类和水温。然而，关于这些性状及其组合的结论性研究还很缺乏。在这里，我们将实验室实验与对一个温带浅湖的长期数据分析相结合，这些数据分别来自于斑马贻贝入侵前后10年的数据。我们测试了以下假设：在实验室中，斑驴贻贝的过滤率1)在不同的蓝藻种类中会有所不同；2)在临界温度以上会下降。根据野外数据，我们预计白斑贻贝会减少夏季美味蓝藻的生物量，但这种影响在临界温度以上就会消失。我们的结果支持所有四个假设。在实验室实验中，水藻Dolichospermum flos-aquae被归类为白斑贻贝的美味蓝藻，而水藻aphanizomenae、elenkinii和铜绿微囊藻（Microcystis aeruginosa）则被归类为不太美味的蓝藻。过滤率在28.9°C以上下降（CI: 27.6-30.2°C），贻贝在32°C时死亡。我们的长期湖泊数据显示，在白斑贻贝入侵后，蓝藻生物量有所下降，但仅低于27.7°C (CI: 26.9-28.4°C)，证实了白斑贻贝过滤的关键热窗。因此，全球变暖将通过增加蓝藻的生长速度和降低白斑贻贝在夏季临界水温以上的过滤速度来促进有害藻华的发生，而在入侵的湖泊中，这一温度正越来越多地达到。在进行HAB预测时必须考虑这个临界热窗。

{"title":"Blooms like it hot, but mussels do not: Influence of invasive quagga mussels on cyanobacteria during summer","authors":"Jonas Mauch , Maider Erize Gardoki , Raphael Neiling , Jan Köhler , Jordan Facey , Sabine Hilt","doi":"10.1016/j.hal.2026.103094","DOIUrl":"10.1016/j.hal.2026.103094","url":null,"abstract":"<div><div>Quagga mussels (<em>Dreissena rostriformis bugensis</em>) are among the most impactful invaders in freshwaters of the Northern Hemisphere. As filter-feeders, they can reduce harmful algal blooms (HABs), but their effects are expected to be dependent on cyanobacteria species and water temperature. However, conclusive studies on these traits and their combination are lacking. Here, we combined laboratory experiments with an analysis of long-term data from a temperate shallow lake 10 years before and after quagga mussel invasion, respectively. We tested the hypotheses that quagga mussel filtration rates in the laboratory would 1) vary among common cyanobacteria species and 2) decrease above a critical temperature. Regarding the field data, we expected that 3) quagga mussels can reduce the summer biovolume of palatable cyanobacteria, but that 4) this effect disappears above a critical temperature. Our results support all four hypotheses. In laboratory experiments, <em>Dolichospermum flos-aquae</em> was classified as palatable to quagga mussels, while <em>Aphanizomenon flos-aquae, Anabaenopsis elenkinii</em> and <em>Microcystis aeruginosa</em> were less-palatable cyanobacteria. Filtration rates decreased above 28.9°C (CI: 27.6–30.2°C) with mussels dying at 32°C. Our long-term lake data show that cyanobacteria biovolumes were lower after quagga mussel invasion, but only below 27.7°C (CI: 26.9–28.4°C), confirming a critical thermal window for quagga mussel filtration. Global warming will therefore facilitate HABs by increasing the growth rates of cyanobacteria and reducing the filtration rates of quagga mussels above critical summer water temperatures, which are increasingly being reached in invaded lakes. This critical thermal window must be considered when making HAB predictions.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"155 ","pages":"Article 103094"},"PeriodicalIF":4.5,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147388068","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}

引用次数: 0

Urea as a rising driver of harmful algal blooms: Integrating global patterns, metabolic pathways, and ecological consequences 尿素作为有害藻华上升的驱动因素：整合全球模式、代谢途径和生态后果

IF 4.5 1区生物学 Q1 MARINE & FRESHWATER BIOLOGY

Harmful Algae

Pub Date : 2026-05-01 Epub Date: 2026-02-17 DOI: 10.1016/j.hal.2026.103087

Huaizhi Qin , Muhamad Syaifudin , Tangcheng Li , Wenkang Fan , Hong Du , Senjie Lin

Urea inputs to aquatic ecosystems have increased rapidly due to intensified fertilizer use, wastewater discharge, and aquaculture expansion, altering nitrogen composition and accelerating eutrophication. However, the physiological, ecological, and evolutionary mechanisms linking urea enrichment to harmful algal blooms (HABs) remain incompletely synthesized. Here, we integrate a bibliometric survey of 818 papers from 2003 to 2024 with a quantitative analysis of 32 physiological studies and a comparative genomic assessment of urea metabolic pathways. Urea concentrations range from the nanomolar scale in open oceans to >20 μM in eutrophic rivers and estuaries—levels sufficient to stimulate urea-preferring taxa. Many HAB-forming dinoflagellates and cyanobacteria exhibit enhanced growth, photosynthetic efficiency, and in some cases, increased toxin production when supplied with urea. Comparative pathway analysis shows that bloom-forming taxa predominantly utilize the energy-efficient urease pathway, whereas non-blooming taxa more commonly rely on the ATP-consuming urea amidolyase (UAL) pathway. Several bloom-forming species are capable of using both pathways, suggesting metabolic flexibility under fluctuating nitrogen regimes. These findings support the hypothesis that anthropogenic urea enrichment acts as a selective pressure favoring taxa capable of rapid and energetically economical nitrogen assimilation. We identify key research gaps—including evolutionary origins of UAL, regulatory divergence between pathways, and interactions with warming and stratification—and provide recommendations for monitoring and management. This synthesis highlights urea as a critical yet underappreciated component of global nitrogen pollution and HAB dynamics.

由于化肥使用、废水排放和水产养殖规模扩大，改变了氮组成并加速了富营养化，对水生生态系统的尿素投入迅速增加。然而，将尿素富集与有害藻华（HABs）联系起来的生理、生态和进化机制尚未完全合成。在这里，我们整合了2003年至2024年818篇论文的文献计量学调查，对32项生理学研究进行了定量分析，并对尿素代谢途径进行了比较基因组评估。尿素浓度范围从开放海洋的纳摩尔尺度到富营养化河流和河口的20 μM -足以刺激偏爱尿素的分类群。许多形成有害藻华的鞭毛藻和蓝藻在提供尿素时表现出生长增强、光合效率提高，在某些情况下，毒素产量增加。途径对比分析表明，开花类群主要利用高效脲酶途径，而非开花类群则更多地依赖于消耗atp的尿素酰胺酶途径。一些开花形成物种能够使用这两种途径，这表明在波动的氮制度下代谢的灵活性。这些发现支持了人为尿素富集作为一种选择压力，有利于能够快速和能量经济地同化氮的分类群的假设。我们确定了关键的研究空白-包括UAL的进化起源，途径之间的调节分歧，以及与变暖和分层的相互作用-并为监测和管理提供建议。该合成强调尿素是全球氮污染和赤潮动力学的一个关键但未被充分认识的成分。

{"title":"Urea as a rising driver of harmful algal blooms: Integrating global patterns, metabolic pathways, and ecological consequences","authors":"Huaizhi Qin , Muhamad Syaifudin , Tangcheng Li , Wenkang Fan , Hong Du , Senjie Lin","doi":"10.1016/j.hal.2026.103087","DOIUrl":"10.1016/j.hal.2026.103087","url":null,"abstract":"<div><div>Urea inputs to aquatic ecosystems have increased rapidly due to intensified fertilizer use, wastewater discharge, and aquaculture expansion, altering nitrogen composition and accelerating eutrophication. However, the physiological, ecological, and evolutionary mechanisms linking urea enrichment to harmful algal blooms (HABs) remain incompletely synthesized. Here, we integrate a bibliometric survey of 818 papers from 2003 to 2024 with a quantitative analysis of 32 physiological studies and a comparative genomic assessment of urea metabolic pathways. Urea concentrations range from the nanomolar scale in open oceans to >20 μM in eutrophic rivers and estuaries—levels sufficient to stimulate urea-preferring taxa. Many HAB-forming dinoflagellates and cyanobacteria exhibit enhanced growth, photosynthetic efficiency, and in some cases, increased toxin production when supplied with urea. Comparative pathway analysis shows that bloom-forming taxa predominantly utilize the energy-efficient urease pathway, whereas non-blooming taxa more commonly rely on the ATP-consuming urea amidolyase (UAL) pathway. Several bloom-forming species are capable of using both pathways, suggesting metabolic flexibility under fluctuating nitrogen regimes. These findings support the hypothesis that anthropogenic urea enrichment acts as a selective pressure favoring taxa capable of rapid and energetically economical nitrogen assimilation. We identify key research gaps—including evolutionary origins of UAL, regulatory divergence between pathways, and interactions with warming and stratification—and provide recommendations for monitoring and management. This synthesis highlights urea as a critical yet underappreciated component of global nitrogen pollution and HAB dynamics.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"155 ","pages":"Article 103087"},"PeriodicalIF":4.5,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147388069","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}

引用次数: 0

The suppression of harmful algal blooms in spring 2025 off the Zhe-Min coast, China: A consequence of extreme atmospheric and oceanic forcing 2025年春季浙江沿海有害藻华的抑制：极端大气和海洋强迫的结果

IF 4.5 1区生物学 Q1 MARINE & FRESHWATER BIOLOGY

Harmful Algae

Pub Date : 2026-04-01 Epub Date: 2026-02-07 DOI: 10.1016/j.hal.2026.103076

Weibo Wang , Haifeng Gu

The Zhe-Min coastal region of China, a principal fisheries area, frequently experiences harmful algal blooms (HABs) driven by the nutrient-rich southward current of the Zhe-Min Coastal Current (ZMCC). In spring 2025, however, routine monitoring (since 2001) recorded an unprecedented absence of large-scale HABs. This study investigates the dynamical mechanisms underpinning this suppression. Our analysis indicates that a persistent, record-breaking anomalous northeastward sea surface current inhibited southward nutrient transport to the Fuzhou–Wenzhou coast. Dynamical decomposition shows that this anomalous current resulted from distinct regional processes: off Fuzhou it manifested as a barotropic response to an anomalous cross-shelf sea-level gradient associated with an extremely weak northeasterly monsoon, while off Wenzhou it was predominantly baroclinic, driven by cross-shelf temperature gradients linked to frequent marine heatwaves. The observed thermal extremes are largely attributable to the record-breaking northward shift of the subtropical high-pressure system during the spring of 2025. Moreover, the interaction between a coastal marine cold spell and offshore heatwaves in March promoted cross-shelf transport that exported coastal nutrients offshore. These findings indicate that climate–related shifts—notably weakened monsoonal forcing and increased frequency of extreme thermal events—can act synergistically to form a compound hazard chain that substantially alters coastal physical–biological coupling, however, in this instance, suppressed large-scale HABs outbreak. Future research should pay more attention to the impacts generated by the coupling processes among such extreme events.

浙江沿海地区是中国重要的渔业区域，在富含营养物质的浙闵海流南流的驱动下，有害藻华（HABs）频繁发生。然而，在2025年春季，常规监测（自2001年以来）记录了前所未有的大规模赤潮的缺失。本研究探讨了这种抑制的动力机制。我们的分析表明，持续的、破纪录的东北海面洋流抑制了向南向福州-温州海岸的营养物质输送。动力学分析表明，这一异常海流是由不同的区域过程引起的：在福州附近，它表现为对与极弱东北季风相关的大陆架间海平面梯度异常的正压响应，而在温州附近，它主要是斜压响应，与频繁的海洋热浪相关的大陆架间温度梯度有关。观测到的极端高温主要归因于2025年春季副热带高压系统破纪录的北移。此外，3月份沿海海洋寒流和近海热浪之间的相互作用促进了跨大陆架运输，将沿海营养物质出口到近海。这些发现表明，气候相关的变化——特别是减弱的季风强迫和极端热事件的频率增加——可以协同作用，形成复合危害链，从而大大改变沿海的物理-生物耦合，然而，在这种情况下，抑制了大规模的赤潮爆发。未来的研究应更多地关注这些极端事件之间耦合过程所产生的影响。

{"title":"The suppression of harmful algal blooms in spring 2025 off the Zhe-Min coast, China: A consequence of extreme atmospheric and oceanic forcing","authors":"Weibo Wang , Haifeng Gu","doi":"10.1016/j.hal.2026.103076","DOIUrl":"10.1016/j.hal.2026.103076","url":null,"abstract":"<div><div>The Zhe-Min coastal region of China, a principal fisheries area, frequently experiences harmful algal blooms (HABs) driven by the nutrient-rich southward current of the Zhe-Min Coastal Current (ZMCC). In spring 2025, however, routine monitoring (since 2001) recorded an unprecedented absence of large-scale HABs. This study investigates the dynamical mechanisms underpinning this suppression. Our analysis indicates that a persistent, record-breaking anomalous northeastward sea surface current inhibited southward nutrient transport to the Fuzhou–Wenzhou coast. Dynamical decomposition shows that this anomalous current resulted from distinct regional processes: off Fuzhou it manifested as a barotropic response to an anomalous cross-shelf sea-level gradient associated with an extremely weak northeasterly monsoon, while off Wenzhou it was predominantly baroclinic, driven by cross-shelf temperature gradients linked to frequent marine heatwaves. The observed thermal extremes are largely attributable to the record-breaking northward shift of the subtropical high-pressure system during the spring of 2025. Moreover, the interaction between a coastal marine cold spell and offshore heatwaves in March promoted cross-shelf transport that exported coastal nutrients offshore. These findings indicate that climate–related shifts—notably weakened monsoonal forcing and increased frequency of extreme thermal events—can act synergistically to form a compound hazard chain that substantially alters coastal physical–biological coupling, however, in this instance, suppressed large-scale HABs outbreak. Future research should pay more attention to the impacts generated by the coupling processes among such extreme events.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"154 ","pages":"Article 103076"},"PeriodicalIF":4.5,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146189068","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}

引用次数: 0

Zooplankton feeding behaviour and survival to toxic and non-toxic cyanobacteria during the seasonal bloom progression of a eutrophic lake 富营养化湖泊季节性水华过程中浮游动物对有毒和无毒蓝藻的摄食行为和生存

IF 4.5 1区生物学 Q1 MARINE & FRESHWATER BIOLOGY

Harmful Algae

Pub Date : 2026-04-01 Epub Date: 2025-12-12 DOI: 10.1016/j.hal.2025.103045

Pinelopi Ntetsika , Salomé Stauffer , Stefanie Eyring , Marta Reyes , Xuejian Wang , Elisabeth M.-L. Janssen , Francesco Pomati

Harmful cyanobacterial blooms pose increasing threats to aquatic ecosystems and human health; yet, the role of zooplankton grazing in regulating blooms remains understudied. We investigated the seasonal feeding behaviour and fitness consequences of feeding preferences in natural zooplankton communities for toxic (microcystin-producing) versus non-toxic cyanobacteria across temperature gradients in eutrophic Lake Greifen, Switzerland. We conducted monthly experiments from April to October 2023 to test the grazing behaviour of four zooplankton groups (daphnids, calanoid copepods, cyclopoid copepods, and microzooplankton) exposed to mixed diets of green algae and either toxic or non-toxic Microcystis strains at 15 °C and 25 °C.

Contrary to expectations of cyanobacteria avoidance, zooplankton exhibited predominantly non-selective grazing throughout the seasonal succession, consuming both toxic and non-toxic cyanobacteria at similar rates, regardless of temperature. Notably, during the peaks of phytoplankton abundance (April and September), mesozooplankton demonstrated a selective preference for cyanobacteria over green algae, particularly non-toxic strains. Temperature effects were subtle but revealed metabolic constraints: elevated temperatures occasionally triggered selective consumption of cyanobacteria in copepods, while fitness costs (survival) from exposure to toxic species were mostly restricted to transitional bloom periods and high-temperature conditions.

These findings suggest that toxic cyanobacteria may not always evade grazing pressure through secondary metabolite deterrent effects. Our results suggest that zooplankton communities can adapt and graze on cyanobacteria regardless of toxicity under the tested conditions, even during bloom conditions. These observations highlight the potential for zooplankton to interact with cyanobacterial populations, which may have implications for bloom prediction and management strategies, particularly under climate warming scenarios.

有害的蓝藻繁殖对水生生态系统和人类健康构成越来越大的威胁；然而，浮游动物放牧在调节藻华中的作用仍未得到充分研究。我们研究了瑞士富营养化湖Greifen天然浮游动物群落中有毒（产生微囊藻毒素）与无毒蓝藻在不同温度梯度下的季节性摄食行为和摄食偏好的适应性后果。我们于2023年4月至10月进行了月度实验，测试了在15°C和25°C条件下，4种浮游动物类群（水蚤类、花萼类桡足类、环足类桡足类和微型浮游动物）在绿藻和有毒或无毒微囊藻菌株混合饮食中的放牧行为。与预期的避免蓝藻相反，浮游动物在整个季节演替中表现出主要的非选择性放牧，无论温度如何，它们以相似的速度消耗有毒和无毒的蓝藻。值得注意的是，在浮游植物丰度的高峰期（4月和9月），中浮游动物表现出对蓝藻的选择性偏好，而不是绿藻，特别是无毒菌株。温度影响是微妙的，但揭示了代谢限制：升高的温度偶尔会触发桡足类对蓝藻的选择性消耗，而暴露于有毒物种的适应成本（生存）主要局限于过渡开花期和高温条件。这些发现表明，有毒的蓝藻可能并不总是通过次级代谢物的威慑作用来逃避放牧压力。我们的研究结果表明，在测试条件下，浮游动物群落可以适应并以蓝藻为食，而不考虑毒性，即使在水华条件下也是如此。这些观察结果突出了浮游动物与蓝藻种群相互作用的潜力，这可能对水华预测和管理策略产生影响，特别是在气候变暖的情况下。

{"title":"Zooplankton feeding behaviour and survival to toxic and non-toxic cyanobacteria during the seasonal bloom progression of a eutrophic lake","authors":"Pinelopi Ntetsika , Salomé Stauffer , Stefanie Eyring , Marta Reyes , Xuejian Wang , Elisabeth M.-L. Janssen , Francesco Pomati","doi":"10.1016/j.hal.2025.103045","DOIUrl":"10.1016/j.hal.2025.103045","url":null,"abstract":"<div><div>Harmful cyanobacterial blooms pose increasing threats to aquatic ecosystems and human health; yet, the role of zooplankton grazing in regulating blooms remains understudied. We investigated the seasonal feeding behaviour and fitness consequences of feeding preferences in natural zooplankton communities for toxic (microcystin-producing) versus non-toxic cyanobacteria across temperature gradients in eutrophic Lake Greifen, Switzerland. We conducted monthly experiments from April to October 2023 to test the grazing behaviour of four zooplankton groups (daphnids, calanoid copepods, cyclopoid copepods, and microzooplankton) exposed to mixed diets of green algae and either toxic or non-toxic <em>Microcystis</em> strains at 15 °C and 25 °C.</div><div>Contrary to expectations of cyanobacteria avoidance, zooplankton exhibited predominantly non-selective grazing throughout the seasonal succession, consuming both toxic and non-toxic cyanobacteria at similar rates, regardless of temperature. Notably, during the peaks of phytoplankton abundance (April and September), mesozooplankton demonstrated a selective preference for cyanobacteria over green algae, particularly non-toxic strains. Temperature effects were subtle but revealed metabolic constraints: elevated temperatures occasionally triggered selective consumption of cyanobacteria in copepods, while fitness costs (survival) from exposure to toxic species were mostly restricted to transitional bloom periods and high-temperature conditions.</div><div>These findings suggest that toxic cyanobacteria may not always evade grazing pressure through secondary metabolite deterrent effects. Our results suggest that zooplankton communities can adapt and graze on cyanobacteria regardless of toxicity under the tested conditions, even during bloom conditions. These observations highlight the potential for zooplankton to interact with cyanobacterial populations, which may have implications for bloom prediction and management strategies, particularly under climate warming scenarios.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"154 ","pages":"Article 103045"},"PeriodicalIF":4.5,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145802022","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}

引用次数: 0

Evaluation of a field method for qPCR analysis of toxigenic cyanobacteria 产毒蓝藻qPCR现场分析方法的评价

IF 4.5 1区生物学 Q1 MARINE & FRESHWATER BIOLOGY

Harmful Algae

Pub Date : 2026-04-01 Epub Date: 2026-02-02 DOI: 10.1016/j.hal.2026.103069

Ian Struewing , Aimèe Henderson , Nathan Sienkiewicz , William Hobbs , Stacey Cochran , Jingrang Lu

Quantitative Polymerase Chain Reaction (qPCR) is a well-established method for molecular detection and quantification of microorganisms. Molecular detection of toxigenic cyanobacteria using qPCR has also been employed as a useful tool for predicting cyanotoxin production and formation of harmful cyanobacterial blooms (cHABs). Recently, portable thermocyclers and extraction procedures and reagents have been developed for onsite application of qPCR analysis. However, use of portable qPCR analysis for the detection and quantification of toxigenic cyanobacteria has not been evaluated. Here, we provide an evaluation of a field method for DNA extraction and qPCR analysis using the Biomeme Franklin thermocycler for detection of toxigenic cyanobacteria. The results obtained from the portable device provide identification and quantification of toxigenic Microcystis and are comparable with lab-based extraction and analysis. This field method for extraction and qPCR analysis will provide alternative research tools to evaluate source and recreational water for toxic cyanobacteria. This field method allows users to obtain immediate on-site results for identification and quantification of toxigenic Microcystis.

定量聚合酶链反应（qPCR）是一种成熟的微生物分子检测和定量方法。利用qPCR技术进行产毒蓝藻的分子检测也被用作预测蓝藻毒素产生和有害蓝藻华（cHABs）形成的有用工具。最近，便携式热循环仪和提取程序和试剂已开发用于qPCR分析的现场应用。然而，使用便携式qPCR分析检测和定量产毒蓝藻尚未评估。在这里，我们提供了一种评估的DNA提取和qPCR分析的现场方法，使用Biomeme Franklin热循环器检测产毒蓝藻。从便携式装置获得的结果提供了产毒微囊藻的鉴定和定量，并与实验室提取和分析相媲美。这种现场提取和qPCR分析方法将为评估有毒蓝藻的来源和娱乐用水提供替代研究工具。这种现场方法允许用户获得即时的现场结果，用于鉴定和定量产毒微囊藻。

{"title":"Evaluation of a field method for qPCR analysis of toxigenic cyanobacteria","authors":"Ian Struewing , Aimèe Henderson , Nathan Sienkiewicz , William Hobbs , Stacey Cochran , Jingrang Lu","doi":"10.1016/j.hal.2026.103069","DOIUrl":"10.1016/j.hal.2026.103069","url":null,"abstract":"<div><div>Quantitative Polymerase Chain Reaction (qPCR) is a well-established method for molecular detection and quantification of microorganisms. Molecular detection of toxigenic cyanobacteria using qPCR has also been employed as a useful tool for predicting cyanotoxin production and formation of harmful cyanobacterial blooms (cHABs). Recently, portable thermocyclers and extraction procedures and reagents have been developed for onsite application of qPCR analysis. However, use of portable qPCR analysis for the detection and quantification of toxigenic cyanobacteria has not been evaluated. Here, we provide an evaluation of a field method for DNA extraction and qPCR analysis using the Biomeme Franklin thermocycler for detection of toxigenic cyanobacteria. The results obtained from the portable device provide identification and quantification of toxigenic <em>Microcystis</em> and are comparable with lab-based extraction and analysis. This field method for extraction and qPCR analysis will provide alternative research tools to evaluate source and recreational water for toxic cyanobacteria. This field method allows users to obtain immediate on-site results for identification and quantification of toxigenic <em>Microcystis.</em></div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"154 ","pages":"Article 103069"},"PeriodicalIF":4.5,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146189069","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}

引用次数: 0

Diversity and toxicity of Coolia from the Ryukyu Islands, with a description of Coolia kabiraensis sp. nov 琉球群岛Coolia的多样性和毒性——兼论kakiraensis sp. nov .

IF 4.5 1区生物学 Q1 MARINE & FRESHWATER BIOLOGY

Harmful Algae

Pub Date : 2026-04-01 Epub Date: 2026-02-06 DOI: 10.1016/j.hal.2026.103075

Shaun Cunningham , Siratee Riewluang , Aika Yamaguchi , Anne Rolton , Kevin C. Wakeman

Coolia is a widely distributed genus of marine benthic dinoflagellates, with some species known to produce bioactive compounds toxic to marine life. In this study, we investigated the diversity and toxicity of Coolia from the Ryukyu Islands (subtropical Japan), integrating morphological characterization, molecular phylogenetics, and Artemia toxicity assays. Five species were identified: four previously described, including the first record of C. palmyrensis in Japan, and one undescribed species, Coolia kabiraensis sp. nov. Coolia kabiraensis closely resembles members of the Coolia monotis species complex, which are difficult to distinguish morphologically. Phylogenetic analysis using ITS1–5.8S–ITS2 and 28S rDNA (D1–D3) genetic markers placed this taxon in a distinct, well-supported clade, supporting its recognition as a new species. A systematic review of global Coolia records, incorporating peer-reviewed studies, GenBank sequences, grey literature, and culture collections, was used to contextualize regional diversity. Species richness in the Ryukyu Islands was relatively high but comparable to that of other subtropical and tropical regions. Toxicity screening assays showed that extracts from C. kabiraensis, C. palmyrensis, C. canariensis, and C. tropicalis caused no statistically significant mortality of Artemia after 48 h. In contrast, C. malayensis extracts caused 40–85% mortality, indicating potential risk to marine life. These findings highlight the cryptic diversity, variable toxicity, and broad geographic distribution of Coolia species. Understanding species composition and toxicity patterns is essential for monitoring harmful algal blooms and anticipating future changes under climate-driven shifts in benthic microalgal assemblages.

Coolia是一种分布广泛的海洋底栖鞭毛藻属，其中一些物种已知会产生对海洋生物有毒的生物活性化合物。在本研究中，我们研究了来自琉球群岛（日本亚热带）的Coolia的多样性和毒性，综合形态学表征，分子系统发育和Artemia毒性分析。共鉴定出5个种，其中4个为先前描述的种，包括日本首次记录的C. palmyrensis，以及1个未描述的种Coolia kabiraensis sp. nov. Coolia kabiraensis与Coolia monotis种复群的成员非常相似，但在形态学上难以区分。利用ITS1-5.8S-ITS2和28S rDNA （D1-D3）遗传标记进行系统发育分析，将该分类单元置于一个独特的、支持良好的进化支中，支持其作为新种的识别。对全球Coolia记录进行系统回顾，结合同行评议研究、GenBank序列、灰色文献和文化收藏，对区域多样性进行了背景分析。琉球群岛的物种丰富度相对较高，但与其他亚热带和热带地区相当。毒性筛选试验显示，卡比拉草、棕榈芽草、加那利草和热带草提取物对Artemia 48 h后的死亡率无统计学意义，而马来草提取物对Artemia 48 h后的死亡率为40-85%，表明对海洋生物存在潜在风险。这些发现突出了Coolia物种的隐性多样性，可变毒性和广泛的地理分布。了解物种组成和毒性模式对于监测有害藻华和预测气候驱动下底栖微藻组合的未来变化至关重要。

{"title":"Diversity and toxicity of Coolia from the Ryukyu Islands, with a description of Coolia kabiraensis sp. nov","authors":"Shaun Cunningham , Siratee Riewluang , Aika Yamaguchi , Anne Rolton , Kevin C. Wakeman","doi":"10.1016/j.hal.2026.103075","DOIUrl":"10.1016/j.hal.2026.103075","url":null,"abstract":"<div><div><em>Coolia</em> is a widely distributed genus of marine benthic dinoflagellates, with some species known to produce bioactive compounds toxic to marine life. In this study, we investigated the diversity and toxicity of <em>Coolia</em> from the Ryukyu Islands (subtropical Japan), integrating morphological characterization, molecular phylogenetics, and <em>Artemia</em> toxicity assays. Five species were identified: four previously described, including the first record of <em>C. palmyrensis</em> in Japan, and one undescribed species, <em>Coolia kabiraensis</em> sp. nov. <em>Coolia kabiraensis</em> closely resembles members of the <em>Coolia monotis</em> species complex, which are difficult to distinguish morphologically. Phylogenetic analysis using ITS1–5.8S–ITS2 and 28S rDNA (D1–D3) genetic markers placed this taxon in a distinct, well-supported clade, supporting its recognition as a new species. A systematic review of global <em>Coolia</em> records, incorporating peer-reviewed studies, GenBank sequences, grey literature, and culture collections, was used to contextualize regional diversity. Species richness in the Ryukyu Islands was relatively high but comparable to that of other subtropical and tropical regions. Toxicity screening assays showed that extracts from <em>C. kabiraensis, C. palmyrensis, C. canariensis</em>, and <em>C. tropicalis</em> caused no statistically significant mortality of <em>Artemia</em> after 48 h. In contrast, <em>C. malayensis</em> extracts caused 40–85% mortality, indicating potential risk to marine life. These findings highlight the cryptic diversity, variable toxicity, and broad geographic distribution of <em>Coolia</em> species. Understanding species composition and toxicity patterns is essential for monitoring harmful algal blooms and anticipating future changes under climate-driven shifts in benthic microalgal assemblages.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"154 ","pages":"Article 103075"},"PeriodicalIF":4.5,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146189070","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}

引用次数: 0

The impact of Ulva prolifera green tide on the diatom-dinoflagellate taxa in the Southern Yellow Sea, China 藻绿潮对南黄海硅藻-鞭毛藻类群的影响

IF 4.5 1区生物学 Q1 MARINE & FRESHWATER BIOLOGY

Harmful Algae

Pub Date : 2026-03-01 Epub Date: 2026-01-14 DOI: 10.1016/j.hal.2026.103062

Xinyu Li , Yingzhe Wang , Liqiang Fan , Jing Zhao , Xiulin Wang , Keqiang Li

Microalgal taxa distribution trends of diatom dominance, dinoflagellate dominance, and dinoflagellate-to-diatom succession have been observed in the southern, middle, and northern green tide areas, respectively, during Ulva prolifera outbreaks in the Southern Yellow Sea. However, little is known about the interactions between macroalgal and microalgal taxa associated with biogeochemical processes. Focusing on the impact of the Ulva spp. on microalgal communities, we constructed a Nutrient-Ulva-Microalgae-Detritus (NUMAD) model using ship-based mesocosm culture experiments. Culture experiments and the NUMAD model revealed higher dynamic rates of nutrient uptake and growth of U. prolifera than microalgae under oligotrophic conditions, consistent with the R strategy for diatoms with sufficient ambient nutrition. There is an ecological niche overlap between U. prolifera and diatom taxa, which makes the succession from diatom taxa to dinoflagellate taxa in the macro-microalgae co-cultural systems. We demonstrated that diatoms exceeding dinoflagellates with R strategy and ecological niche overlap compete against U. prolifera in the initial stage of the green tide, while dinoflagellates exceeding diatoms with K strategy and ecological niche differences compete against U. prolifera in the expanded stages of the green tide. This study provides new insights into the succession of macro-microalgae and a scientific basis for the mitigation of Ulva spp. green tides in the Yellow Sea.

在南黄海藻爆发期间，分别观察了南、中、北绿潮区硅藻优势、甲藻优势和甲藻-硅藻演替的微藻类群分布趋势。然而，人们对大藻和微藻之间的相互作用与生物地球化学过程的关系知之甚少。针对Ulva sp .对微藻群落的影响，采用船舶中游环境培养实验，构建了营养物-Ulva-微藻-碎屑（NUMAD）模型。培养实验和NUMAD模型显示，在低营养条件下，藻藻的营养吸收和生长的动态速率高于微藻，这与环境营养充足的硅藻的R策略一致。巨藻与硅藻类群之间存在生态位重叠，使得巨藻共生系统从硅藻类群向鞭毛藻类群演替。结果表明，在绿潮初始阶段，具有R策略和生态位重叠的超过甲藻的硅藻与浒苔竞争，而在绿潮扩展阶段，具有K策略和生态位差异的超过甲藻的甲藻与浒苔竞争。该研究为宏观微藻演替提供了新的认识，并为减缓黄海绿潮提供了科学依据。

{"title":"The impact of Ulva prolifera green tide on the diatom-dinoflagellate taxa in the Southern Yellow Sea, China","authors":"Xinyu Li , Yingzhe Wang , Liqiang Fan , Jing Zhao , Xiulin Wang , Keqiang Li","doi":"10.1016/j.hal.2026.103062","DOIUrl":"10.1016/j.hal.2026.103062","url":null,"abstract":"<div><div>Microalgal taxa distribution trends of diatom dominance, dinoflagellate dominance, and dinoflagellate-to-diatom succession have been observed in the southern, middle, and northern green tide areas, respectively, during <em>Ulva prolifera</em> outbreaks in the Southern Yellow Sea. However, little is known about the interactions between macroalgal and microalgal taxa associated with biogeochemical processes. Focusing on the impact of the <em>Ulva spp.</em> on microalgal communities, we constructed a Nutrient-Ulva-Microalgae-Detritus (NUMAD) model using ship-based mesocosm culture experiments. Culture experiments and the NUMAD model revealed higher dynamic rates of nutrient uptake and growth of <em>U. prolifera</em> than microalgae under oligotrophic conditions, consistent with the <em>R</em> strategy for diatoms with sufficient ambient nutrition. There is an ecological niche overlap between <em>U. prolifera</em> and diatom taxa, which makes the succession from diatom taxa to dinoflagellate taxa in the macro-microalgae co-cultural systems. We demonstrated that diatoms exceeding dinoflagellates with <em>R</em> strategy and ecological niche overlap compete against <em>U. prolifera</em> in the initial stage of the green tide, while dinoflagellates exceeding diatoms with <em>K</em> strategy and ecological niche differences compete against <em>U. prolifera</em> in the expanded stages of the green tide. This study provides new insights into the succession of macro-microalgae and a scientific basis for the mitigation of <em>Ulva spp.</em> green tides in the Yellow Sea.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"153 ","pages":"Article 103062"},"PeriodicalIF":4.5,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146034876","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}

引用次数: 0

Tropical coastal seas are overlooked hotspots of Pseudo-nitzschia diversity 热带沿海海域是被忽视的伪尼茨氏菌多样性热点

IF 4.5 1区生物学 Q1 MARINE & FRESHWATER BIOLOGY

Harmful Algae

Pub Date : 2026-03-01 Epub Date: 2026-01-15 DOI: 10.1016/j.hal.2026.103063

Biaobiao Niu , Cuiwen Liang , Fang Yue , Shiyu Wu , Yang Li , Songhui Lu

Pseudo-nitzschia is a globally distributed diatom genus with multiple domoic-acid (DA)–producing species that pose ecological and economic risks. Although tropical waters have recently been hypothesized to host rich Pseudo-nitzschia diversity, their actual diversity, cryptic lineages and toxin-environment relationships remain unclear. Here, we conducted a large-scale summer survey across 65 stations along the Chinese coast of the South China Sea using ITS1 metabarcoding, haplotype network analysis and LC-MS/MS toxin quantification. We identified 50 taxa, including four novel phylotypes and 26 newly recorded in this region, representing the highest richness level documented worldwide. Substantial intraspecific divergence occurred in dominant species, especially P. galaxiae, suggesting a cryptic species complex and ongoing diversification. Dissolved DA (dDA) occurred at 75.4% of stations, with a content of 7.7–351.4 ng L^–1. The higher toxin levels coincided with the co-occurrence of several toxigenic species despite their low relative abundance (<0.4% of total Pseudo-nitzschia reads), indicating a collective contribution to toxin accumulation. Temperature was the strongest environmental predictor of community turnover and toxin variation. Both total and toxigenic Pseudo-nitzschia richness decreased with rising temperature; in particular, a temperature range of 25–29°C corresponded to higher diversity and elevated dDA levels. Contrastly when temperature was above 29°C, Pseudo-nitzschia assemblages were dominated by warm-adapted and largely non-toxic taxa such as P. calliantha, corresponding to low dDA levels. Our findings provide comprehensive molecular evidence that tropical coasts are Pseudo-nitzschia diversity hotspots. Temperature-mediated restructuring of communities links Pseudo-nitzschia diversity to toxin dynamics, highlighting potential climate-driven shifts in HAB risk in low-latitude seas.

伪硅藻属是一种全球分布的硅藻属，具有多种产生软骨藻酸（DA）的物种，具有生态和经济风险。虽然热带水域最近被假设拥有丰富的伪尼茨奇亚多样性，但它们的实际多样性、神秘谱系和毒素与环境的关系仍不清楚。本文利用ITS1元条形码、单倍型网络分析和LC-MS/MS毒素定量技术，对中国南海沿岸65个站点进行了夏季大规模调查。鉴定出50个分类群，其中4个新种型和26个新记录种型，具有世界上最高的丰富度。优势种（尤其是P. galaxae）存在大量种内分化，表明存在一种隐蔽的物种复杂性和持续的多样化。75.4%的站点出现溶解DA (dDA)，含量为7.7 ~ 351.4 ng L-1。较高的毒素水平与几种产毒物种的共存相吻合，尽管它们的相对丰度较低（占伪尼齐亚菌总丰度的0.4%），表明毒素积累的集体贡献。温度是群落更替和毒素变化的最强环境预测因子。总丰富度和产毒丰富度均随温度升高而降低；特别是25-29°C的温度范围对应较高的多样性和较高的dDA水平。而当温度高于29°C时，伪nitzschia组合以暖适应且大部分无毒的类群（如P. calliantha）为主，对应于低dDA水平。本研究结果为热带海岸是伪尼茨氏菌多样性热点地区提供了全面的分子证据。温度介导的群落重组将伪尼茨氏菌多样性与毒素动态联系起来，突出了低纬度海洋中潜在的气候驱动的赤潮风险变化。

{"title":"Tropical coastal seas are overlooked hotspots of Pseudo-nitzschia diversity","authors":"Biaobiao Niu , Cuiwen Liang , Fang Yue , Shiyu Wu , Yang Li , Songhui Lu","doi":"10.1016/j.hal.2026.103063","DOIUrl":"10.1016/j.hal.2026.103063","url":null,"abstract":"<div><div><em>Pseudo-nitzschia</em> is a globally distributed diatom genus with multiple domoic-acid (DA)–producing species that pose ecological and economic risks. Although tropical waters have recently been hypothesized to host rich <em>Pseudo-nitzschia</em> diversity, their actual diversity, cryptic lineages and toxin-environment relationships remain unclear. Here, we conducted a large-scale summer survey across 65 stations along the Chinese coast of the South China Sea using ITS1 metabarcoding, haplotype network analysis and LC-MS/MS toxin quantification. We identified 50 taxa, including four novel phylotypes and 26 newly recorded in this region, representing the highest richness level documented worldwide. Substantial intraspecific divergence occurred in dominant species, especially <em>P. galaxiae</em>, suggesting a cryptic species complex and ongoing diversification. Dissolved DA (dDA) occurred at 75.4% of stations, with a content of 7.7–351.4 ng L<sup>–1</sup>. The higher toxin levels coincided with the co-occurrence of several toxigenic species despite their low relative abundance (<0.4% of total <em>Pseudo-nitzschia</em> reads), indicating a collective contribution to toxin accumulation. Temperature was the strongest environmental predictor of community turnover and toxin variation. Both total and toxigenic <em>Pseudo-nitzschia</em> richness decreased with rising temperature; in particular, a temperature range of 25–29°C corresponded to higher diversity and elevated dDA levels. Contrastly when temperature was above 29°C, <em>Pseudo-nitzschia</em> assemblages were dominated by warm-adapted and largely non-toxic taxa such as <em>P. calliantha</em>, corresponding to low dDA levels. Our findings provide comprehensive molecular evidence that tropical coasts are <em>Pseudo-nitzschia</em> diversity hotspots. Temperature-mediated restructuring of communities links <em>Pseudo-nitzschia</em> diversity to toxin dynamics, highlighting potential climate-driven shifts in HAB risk in low-latitude seas.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"153 ","pages":"Article 103063"},"PeriodicalIF":4.5,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146035229","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}

引用次数: 0

Comparative evaluation of 18S rDNA V4 and 28S rDNA D1–2 regions for resolving Alexandrium species diversity to improve its use for metabarcoding 18S rDNA V4区和28S rDNA D1-2区在亚历山大菌物种多样性分析中的比较评价，以提高其在元条形码中的应用

IF 4.5 1区生物学 Q1 MARINE & FRESHWATER BIOLOGY

Harmful Algae

Pub Date : 2026-03-01 Epub Date: 2026-02-02 DOI: 10.1016/j.hal.2026.103073

Xiangxiang Ding , Xianliang Huang , Nansheng Chen

Many Alexandrium species can develop harmful algal blooms (HABs) associated with paralytic shellfish poisoning (PSP), making their accurate identification critical. Morphological similarity among Alexandrium species limits their identification, whereas molecular marker-based methods are effective, resulting in the accumulation of vast molecular data. However, the existence of these massive molecular sequences makes it confusing to select reference sequences for taxonomical and diversity studies. To address this, we mined and curated molecular marker sequences of 18S rDNA V4 and 28S rDNA D1–2 for Alexandrium species from NCBI NT database. We built the first reference 28S rDNA D1–2 database for 27 Alexandrium species, and for the 18S rDNA V4 region, our results expanded PR² database by adding sequences for two additional Alexandrium species and proposed to eliminate two contaminated sequences. Furthermore, we characterized intra-genomic variations (IGVs) for both 18S rDNA V4 and 28S rDNA D1–2, and experimentally confirmed the existence of 18S rDNA V4 IGVs in Alexandrium species. Both single-cell sequencing and database analysis results showed that an Alexandrium cell typically harbors IGVs with the co-existence of usually one dominant and multiple non-dominant sequences, with non-dominant sequences potentially matching another species’ dominant sequence. Therefore, only dominant sequences of each Alexandrium species were proposed to be included in reference databases for clarity. We also confirmed that 28S rDNA D1–2 has higher resolution for identifying Alexandrium species. Through clarifying the characteristics of these molecular markers and providing curated datasets, this work enhances metabarcoding accuracy for early detection of toxic Alexandrium populations.

许多亚历山大菌可以产生与麻痹性贝类中毒（PSP）相关的有害藻华（HABs），因此准确识别它们至关重要。亚历山大属植物的形态相似性限制了它们的鉴定，而基于分子标记的方法是有效的，积累了大量的分子数据。然而，这些大量分子序列的存在给分类和多样性研究选择参考序列带来了困惑。为了解决这一问题，我们从NCBI NT数据库中挖掘和整理了亚历山大属植物18S rDNA V4和28S rDNA D1-2的分子标记序列。我们建立了27个Alexandrium物种的第一个参考28S rDNA D1-2数据库，在18S rDNA V4区域，我们的研究结果通过增加两个Alexandrium物种的序列扩展了PR2数据库，并提出了消除两个污染序列的建议。此外，我们还鉴定了18S rDNA V4和28S rDNA D1-2的基因组内变异（igv），并通过实验证实了18S rDNA V4 igv在亚历山大属植物中存在。单细胞测序和数据库分析结果都表明，Alexandrium细胞中典型的igv通常是一个显性序列和多个非显性序列共存，非显性序列可能与另一个物种的显性序列匹配。因此，为了清晰起见，建议仅将每个亚历山大属物种的优势序列纳入参考数据库。结果表明，28S rDNA D1-2具有较高的鉴别亚历山大菌的分辨率。通过澄清这些分子标记的特征并提供整理的数据集，本工作提高了亚条形码的准确性，用于有毒亚历山大菌种群的早期检测。

{"title":"Comparative evaluation of 18S rDNA V4 and 28S rDNA D1–2 regions for resolving Alexandrium species diversity to improve its use for metabarcoding","authors":"Xiangxiang Ding , Xianliang Huang , Nansheng Chen","doi":"10.1016/j.hal.2026.103073","DOIUrl":"10.1016/j.hal.2026.103073","url":null,"abstract":"<div><div>Many <em>Alexandrium</em> species can develop harmful algal blooms (HABs) associated with paralytic shellfish poisoning (PSP), making their accurate identification critical. Morphological similarity among <em>Alexandrium</em> species limits their identification, whereas molecular marker-based methods are effective, resulting in the accumulation of vast molecular data. However, the existence of these massive molecular sequences makes it confusing to select reference sequences for taxonomical and diversity studies. To address this, we mined and curated molecular marker sequences of 18S rDNA V4 and 28S rDNA D1–2 for <em>Alexandrium</em> species from NCBI NT database. We built the first reference 28S rDNA D1–2 database for 27 <em>Alexandrium</em> species, and for the 18S rDNA V4 region, our results expanded PR<sup>2</sup> database by adding sequences for two additional <em>Alexandrium</em> species and proposed to eliminate two contaminated sequences. Furthermore, we characterized intra-genomic variations (IGVs) for both 18S rDNA V4 and 28S rDNA D1–2, and experimentally confirmed the existence of 18S rDNA V4 IGVs in <em>Alexandrium</em> species. Both single-cell sequencing and database analysis results showed that an <em>Alexandrium</em> cell typically harbors IGVs with the co-existence of usually one dominant and multiple non-dominant sequences, with non-dominant sequences potentially matching another species’ dominant sequence. Therefore, only dominant sequences of each <em>Alexandrium</em> species were proposed to be included in reference databases for clarity. We also confirmed that 28S rDNA D1–2 has higher resolution for identifying <em>Alexandrium</em> species. Through clarifying the characteristics of these molecular markers and providing curated datasets, this work enhances metabarcoding accuracy for early detection of toxic <em>Alexandrium</em> populations.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"153 ","pages":"Article 103073"},"PeriodicalIF":4.5,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146188752","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}

引用次数: 0