Harmful Algae最新文献

The Adriatic Sea mucilage: The history of a hidden harmful dinoflagellate bloom 亚得里亚海粘液：一个隐藏的有害鞭毛藻华的历史

IF 4.5 1区生物学 Q1 MARINE & FRESHWATER BIOLOGY

Harmful Algae

Pub Date : 2026-01-24 DOI: 10.1016/j.hal.2026.103065

Rossella Pistocchi , Franca Guerrini , Mara Simonazzi , Silvana Vanucci , Monica Cangini , Stefania Milandri , Cristina Mazziotti , Laura Pezzolesi

Mucilage events, characterized by the accumulation of gelatinous, polysaccharide-rich organic aggregates in seawater, are irregularly occurring phenomena in the northern Adriatic Sea. While mucilage in other seas is typically linked to blooms of a single phytoplankton or phytobenthic species, Adriatic events have been mostly attributed to complex biogeochemical processes, rapidly leading to the formation of extensive gelatinous masses. Long-term studies on Northern Adriatic phytoplankton communities have revealed a consistent association, since the 1990s, between mucilage events and blooms of a non-toxic dinoflagellate. Originally identified as Gonyaulax fragilis, the ongoing debate regarding its definitive classification leads us to refer to the species as Gonyaulax cf. hyalina. Generally, this species acts as the primary biological trigger for these phenomena, which subsequently develop into a distinct, recurrent mucilage-associated microbial ecosystem. This review provides a comprehensive synthesis of the taxonomic debate, the main hypotheses proposed over the years, historical and recent evidence leading to G. cf. hyalina as the mucilage causative organism, and the ecological and economic impacts of these outbreaks. Regarding the interannual variability of the events, a link with specific environmental conditions could not be assessed; however, based on G. cf. hyalina growth and nutrient dynamics, we speculate about the importance of specific nutritional requirements (i.e., phosphate inputs or still unknown organic compounds) and of competitive interactions. This review would contribute to increasing knowledge on the most recurrent mucilage phenomenon in the Mediterranean Sea, opening the question on the inclusion of the investigated species in the list of harmful algal species.

黏液事件是亚得里亚海北部不规则发生的现象，其特征是凝胶状、富含多糖的有机聚集体在海水中积累。虽然其他海域的粘液通常与单一浮游植物或底栖植物物种的大量繁殖有关，但亚得里亚海事件主要归因于复杂的生物地球化学过程，迅速导致广泛胶质团块的形成。自20世纪90年代以来，对北亚得里亚海浮游植物群落的长期研究表明，粘液事件与无毒鞭毛藻的大量繁殖之间存在一致的联系。最初被确定为脆弱Gonyaulax fragilis，关于其最终分类的持续争论使我们将该物种称为Gonyaulax cf. hyalina。一般来说，这个物种作为这些现象的主要生物触发器，随后发展成一个独特的，反复出现的粘液相关微生物生态系统。这篇综述提供了一个全面的综合分类辩论，多年来提出的主要假设，历史和最近的证据，导致G. cf. hyalina作为粘液致病生物，以及这些暴发的生态和经济影响。关于这些事件的年际变率，无法评估其与特定环境条件的联系；然而，基于g.c.f.透明藻的生长和营养动态，我们推测了特定营养需求（即磷酸盐输入或仍未知的有机化合物）和竞争相互作用的重要性。这项审查将有助于增加对地中海最常见的粘液现象的认识，并开启将所调查物种列入有害藻类物种清单的问题。

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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 : 2026-01-15 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。

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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 : 2026-01-14 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。

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引用次数: 0

Effects of nutrient forms on the bloom dynamics and phytoplankton community associated with Prorocentrum cordatum 营养形态对心形原藻华动态和浮游植物群落的影响

IF 4.5 1区生物学 Q1 MARINE & FRESHWATER BIOLOGY

Harmful Algae

Pub Date : 2026-01-13 DOI: 10.1016/j.hal.2026.103061

Chuang Li , Yicheng Wang , Na Jiang , Shuangqing Li , Chenyang Shao , Fengyuan Zhang , Huajun Zhang , Weizhong Chen , Hailong Huang , Haibo Jiang

The coastal waters of the East China Sea (ECS) are facing severe eutrophication, driven primarily by large inputs of nitrogen and phosphorus from land-based sources, which in turn accelerate harmful algal blooms. However, the understanding of the relationship between eutrophic conditions and the mechanisms of algal bloom occurrence remains insufficient. This study investigates a bloom of the toxic dinoflagellate Prorocentrum cordatum (syn. Prorocentrum minimum) in the coastal waters of Xiangshan Bay (XSB), ECS, through in situ nutrient addition experiments and DNA metabarcoding analysis. The addition of dissolved organic phosphorus (DOP) significantly promoted the growth of P. cordatum compared to the -P control (no phosphorus source: f/2-P) (p < 0.05), whereas dissolved inorganic phosphorus (DIP) had no such effect. In contrast, nitrite (NO₂⁻) and urea significantly inhibited the growth of the species relative to the -N control (no nitrogen source: f/2-N) (p < 0.05), while no significant difference was observed between nitrate and ammonium treatments when compared to the -N control. Network analysis indicated that DOP increased the topological complexity but may have reduced the stability of the community network. In contrast, NO₂⁻ and urea appeared to enhance the network stability. These findings emphasize that DOP was a critical phosphorus source for maintaining P. cordatum blooms, while the input of nitrite and urea may inhibit bloom expansion. In summary, this study suggests that DOP may serve as an important phosphorus source facilitating P. cordatum growth under phosphorus-limited conditions, thereby providing a scientific basis for refining phosphorus control and nitrogen source optimization in the context of ECS eutrophication management.

东中国海（ECS）沿海水域正面临严重的富营养化，这主要是由陆源大量输入的氮和磷驱动的，这反过来又加速了有害藻类的繁殖。然而，对富营养化条件与藻华发生机制之间的关系的认识仍然不足。本研究通过原位营养添加实验和DNA元条形码分析，对ECS香山湾（XSB）沿海水域的有毒双鞭毛藻proorocentrum cordatum （syn. proorocentrum minimum）进行了研究。与磷对照（无磷源：f/2-P）相比，添加溶解性有机磷（DOP）显著促进了cordatum的生长（p < 0.05），而添加溶解性无机磷（DIP）则无此影响。相比之下，与-N对照（无氮源：f/2-N）相比，亚硝酸盐（NO₂⁻）和尿素显著抑制了物种的生长（p < 0.05），而与-N对照相比，硝酸盐和铵处理之间没有显著差异。网络分析表明，DOP增加了社区网络的拓扑复杂性，但可能降低了社区网络的稳定性。相反，NO₂和尿素可以增强网络的稳定性。这些结果表明，DOP是维持柱心花的重要磷源，而亚硝酸盐和尿素的输入可能抑制柱心花的扩展。综上所述，本研究提示，在限磷条件下，DOP可能是促进柱头草生长的重要磷源，从而为ECS富营养化管理中细化磷控制和优化氮源提供科学依据。

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引用次数: 0

Time series analysis of the toxic dinoflagellate Alexandrium pseudogonyaulax across Northern European waters 北欧水域有毒双鞭毛藻假gonyaulax Alexandrium的时间序列分析

IF 4.5 1区生物学 Q1 MARINE & FRESHWATER BIOLOGY

Harmful Algae

Pub Date : 2026-01-12 DOI: 10.1016/j.hal.2026.103060

Kristof Moeller , Hans H. Jakobsen , Anette Engesmo , Bengt Karlson , Jacob Carstensen

The harmful dinoflagellate Alexandrium pseudogonyaulax has been associated with the mortality of marine organisms, including fish. Recent evidence, although based on limited data, suggests an increasing presence across Northern European waters. To confirm this hypothesis, we analysed comprehensive long-term time series data from monitoring stations in Germany, Sweden, Denmark and Norway to assess whether A. pseudogonyaulax has established a sustained presence in the study region and to identify potential environmental drivers of its distribution. The findings show that this species is now a recurrent part of the microalgal community, primarily in the Kattegat, Skagerrak, and southern Baltic Sea. The seasonality of this species was found to be consistent across stations as it primarily occurs from May to October, peaking in July. Logistic regression further revealed increasing trends in occurrence at several sites. No consistent environmental drivers of this expansion were found, although its presence was associated with elevated DIN:PO₄ ratios at some stations, suggesting that other ecological mechanisms, such as top-down processes or species competition, may have facilitated proliferation of A. pseudogonyaulax. The species’ salinity tolerance, potential dispersal of resting cysts and climate change-induced warming likely promoted its regional spread, especially into the Baltic Sea. The increasing presence and limited understanding of its toxic effects on marine organisms and humans highlight the need for continued monitoring and further research into its ecological impacts.

有害的鞭毛藻假gonyaulax与包括鱼类在内的海洋生物的死亡有关。尽管基于有限的数据，但最近的证据表明，它们在北欧水域的存在越来越多。为了证实这一假设，我们分析了来自德国、瑞典、丹麦和挪威监测站的综合长期时间序列数据，以评估假gonyaulax是否在研究区域建立了持续的存在，并确定其分布的潜在环境驱动因素。研究结果表明，这个物种现在是微藻群落的一个反复出现的部分，主要在卡特加特、斯卡格拉克和波罗的海南部。各站点的季节分布一致，主要发生在5 - 10月，7月达到高峰。Logistic回归进一步揭示了几个站点的发病率呈上升趋势。虽然这种扩张与某些站点的DIN:PO4比率升高有关，但没有发现一致的环境驱动因素，这表明其他生态机制，如自上而下的过程或物种竞争，可能促进了假gonyaulax的增殖。该物种的耐盐性、休眠囊肿的潜在扩散以及气候变化引起的变暖可能促进了其区域扩散，特别是进入波罗的海。由于其对海洋生物和人类的毒性作用日益增加，而人们对其认识有限，因此需要继续监测和进一步研究其生态影响。

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引用次数: 0

Taxonomic characterization and toxicity assessment of strains of Gambierdiscus belizeanus from Seychelles, southwestern Indian Ocean 西南印度洋塞舌尔伯利兹冈比亚铁鱼的分类特征和毒性评价

IF 4.5 1区生物学 Q1 MARINE & FRESHWATER BIOLOGY

Harmful Algae

Pub Date : 2026-01-06 DOI: 10.1016/j.hal.2026.103059

Nicolas Chomérat , Nikita Rose , Laura Lavenu , Lisbet Díaz-Asencio , Clara Belmont , Stéphanie Hollanda , Francois Oberhansli , Alina Tunin-Ley , Jean Turquet , Marie-Yasmine Dechraoui Bottein

Benthic dinoflagellates associated with human ciguatera poisoning are present in the Indian Ocean and species such as Fukuyoa (formerly Gambierdiscus) yasumotoi, G. toxicus and G. belizeanus have been reported since the mid 90s. Even though, very little information is available concerning the occurrence of Gambierdiscus species and toxicity in the Seychelles waters. This study investigates four Gambierdiscus belizeanus strains isolated from Seychelles, focusing on their morphological and genetic characterization, as well as their potential for neurotoxin production. Water samples were collected in Bay Ternay (West Mahé) and around Saint Anne Island. Culture aliquots were fixed for species identification using microscopy and molecular tools (sequencing of D1-D3 and D8-D10 of LSU rDNA) and toxin production analyzed in a 21-day culture using the N2a bioassay. This revealed detectable low CTX activity in only one of the four strains, estimated to 1.7 fg CTX3C equiv/cell, while the other strains were non-cytotoxic. These findings represent the first molecular and toxicological characterization of G. belizeanus strains from the Seychelles, contributing to the understanding of ciguatera poisoning risks in the Indian Ocean and highlighting the variable toxin production capacity within Gambierdiscus species. Expanding this project to areas with high ciguatera occurrence in the Indian Ocean could help in characterizing the responsible toxins.

与人类雪卡毒素中毒有关的底栖鞭毛藻存在于印度洋，自90年代中期以来，已报道了Fukuyoa（原Gambierdiscus） yasumotoi、G. toxicus和G. belizeanus等物种。尽管如此，关于冈比亚铁鱼种类和在塞舌尔水域的毒性的资料很少。本研究调查了从塞舌尔分离的4株伯利兹甘比铁cus菌株，重点研究了它们的形态和遗传特征，以及它们产生神经毒素的潜力。在海湾泰尔内（西马维尔）和圣安妮岛周围采集了水样。固定培养液，使用显微镜和分子工具（LSU rDNA D1-D3和D8-D10的测序）进行物种鉴定，并使用N2a生物测定法分析21天培养中的毒素产量。结果显示，四株菌株中只有一株的CTX活性较低，估计为1.7 fg CTX3C当量/细胞，而其他菌株则无细胞毒性。这些发现代表了来自塞舌尔的G. belizeanus菌株的第一个分子和毒理学特征，有助于了解印度洋的雪卡毒素中毒风险，并突出冈比亚雪铁物种内的可变毒素生产能力。将这一项目扩大到印度洋上雪卡水含量高的地区，可以帮助确定负责任毒素的特征。

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引用次数: 0

Pleurotus ostreatus polysaccharides improve microcystin-LR-induced intestinal damage in tadpoles by regulating the interaction between microbiota and intestine 平菇多糖通过调节微生物群与肠道的相互作用改善微囊藻毒素诱导的蝌蚪肠道损伤

IF 4.5 1区生物学 Q1 MARINE & FRESHWATER BIOLOGY

Harmful Algae

Pub Date : 2026-01-05 DOI: 10.1016/j.hal.2026.103056

Minglan Fang , Jun He , Shijie Zhou , Pei Hong , Lixia Ke , Hailong Wu , Yilin Shu

Exposure to microcystins (MCs) can cause severe intestinal damage. This study aimed to assess the efficacy of Pleurotus ostreatus polysaccharide in alleviating intestinal damage induced by microcystin-leucine-arginine (MC-LR) in tadpoles. Over a 30-day period, tadpoles (Pelophylax nigromaculatus) received daily exposures to MC-LR and were provided with diets either supplemented with or devoid of P. ostreatus polysaccharide. Results revealed that feeding P. ostreatus polysaccharide conferred protection against MC-LR-induced intestinal damage by mitigating barrier damage, lowering intestinal permeability, and reducing the tissue burden of MC-LR. The LPS/TLR4 pathway response was attenuated, reducing inflammation, and oxidative stress-mediated apoptosis response was also diminished. Gram-negative bacteria (e.g., Bacteroides) in the intestine show a positive correlation with LPS content and the transcription of key genes in the LPS/TLR4 pathway. Metagenomic and metabolite analysis of intestinal contents revealed increased abundance of the alanine-glyoxylate aminotransferase gene (agxt)—the key enzyme converting glyoxylic acid to glycine—and elevated glycine content in the MC-LR-exposed group fed polysaccharide. Results from the corresponding fecal microbiota transplantation experiment aligned with the trends observed in the exposure experiment. Therefore, polysaccharide alleviates MC-LR-induced intestinal damage by enhancing intestinal microbiota-mediated glycine synthesis, supplying raw materials for intestinal GSH production, reducing oxidative stress levels, and simultaneously dampening the LPS/TLR4 pathway response. Moreover, feeding polysaccharides might also regulate the intestine’s defense against pathogens after MC-LR exposure by enhancing lysozyme activity. There is no evidence of intestinal damage in the P. ostreatus exopolysaccharide group. This study highlights for the first time the role of P. ostreatus polysaccharides in mitigating MC-LR-induced intestinal tissue damage, potentially offering novel insights for their application in aquaculture.

暴露于微囊藻毒素（MCs）可导致严重的肠道损伤。本研究旨在评价平菇多糖对小蝌蚪微胱氨酸-亮氨酸-精氨酸（MC-LR）诱导的肠道损伤的缓解作用。在30天的时间里，蝌蚪（Pelophylax nigromaculatus）每天暴露于MC-LR，并提供添加或不添加P. ostreatus多糖的饮食。结果表明，饲用P. ostreatus多糖可减轻MC-LR诱导的肠道屏障损伤，降低肠道通透性，减轻MC-LR的组织负担，从而对MC-LR诱导的肠道损伤起到保护作用。LPS/TLR4通路反应减弱，炎症减轻，氧化应激介导的细胞凋亡反应也减弱。肠内革兰氏阴性菌（如拟杆菌）与LPS含量及LPS/TLR4通路关键基因的转录呈正相关。肠道内容物的宏基因组学和代谢物分析显示，在mc - lr暴露组中，将乙醛酸转化为甘氨酸的关键酶丙氨酸-乙醛酸氨基转移酶基因（agxt）丰度增加，甘氨酸含量升高。相应的粪便微生物群移植实验结果与暴露实验中观察到的趋势一致。因此，多糖通过增强肠道菌群介导的甘氨酸合成，为肠道GSH生产提供原料，降低氧化应激水平，同时抑制LPS/TLR4通路反应，减轻mc - lr诱导的肠道损伤。此外，饲喂多糖还可能通过增强溶菌酶活性来调节暴露于MC-LR后肠道对病原体的防御。没有证据表明，在大肠杆菌胞外多糖组肠道损伤。本研究首次强调了P. ostreatus多糖在减轻mc - lr诱导的肠道组织损伤中的作用，可能为其在水产养殖中的应用提供新的见解。

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引用次数: 0

Tracking marine phycotoxins: spatial distribution and source elucidation of domoic acid and lipophilic shellfish toxins in the Beibu Gulf, South China Sea 海洋藻毒素追踪：南海北部湾软骨藻酸和亲脂贝类毒素的空间分布和来源解析

IF 4.5 1区生物学 Q1 MARINE & FRESHWATER BIOLOGY

Harmful Algae

Pub Date : 2025-12-31 DOI: 10.1016/j.hal.2025.103048

Ying Ji , Guowang Yan , Guixiang Wang , Yadong Cao , Jiangbing Qiu , Tianshen Li , Xin Luo , Wenlu Lan , Zhaohui Wang , Aifeng Li

Harmful algal blooms (HABs) pose escalating threats to marine ecosystems and seafood safety worldwide, particularly in nearshore waters. The Beibu Gulf, located in the northwestern South China Sea, supports rich biodiversity and serves as a major fishing area. To comprehensively understand the current status of phycotoxin pollution, we conducted a basin-wide cruise survey in August 2021, collecting 60 phytoplankton samples to characterize the spatial distribution, compositional profile, and molecular origins of 12 target marine phycotoxins, along with their key environmental drivers. Domoic acid (DA), pectenotoxin-2 (PTX2), homo-yessotoxin (homoYTX), and gymnodimine A (GYM-A) were the predominant phycotoxins detected, whereas okadaic acid (OA), dinophysistoxin (DTX1), and yessotoxin (YTX) were found sporadically (< 6.7% detection rate). The DA was present in 20% of samples (mean 14,424 pg L⁻¹, max 163,434 pg L⁻¹), PTX2 in 36.7% (mean 508 pg L⁻¹, max 2995 pg L⁻¹), homoYTX in 43.3% (mean 1717 pg L⁻¹, max 42,680 pg L⁻¹), and GYM-A exhibited the highest detection rate at 68.3% (mean 37 pg L⁻¹, max 902 pg L⁻¹). Phycotoxin concentrations were markedly higher in the northern waters than in the southern gulf. Metabarcoding revealed 14 potential toxigenic microalgae, 12 of which belonged to Dinophyceae. Redundancy analysis indicated that concentrations of the four dominant phycotoxins were positively correlated with dissolved oxygen and chlorophyll a, but negatively correlated with salinity (p < 0.05). This suggests that low-salinity (28−31), resulting from terrestrial inputs and marine circulation, create favorable niches for toxigenic species. This study elucidates the phycotoxin profiles and their putative toxigenic microalgae in the Beibu Gulf, while highlighting environmental factors that promote phycotoxin production. These findings provide foundational insights into HAB dynamics in tropical estuarine systems, aiding future monitoring and management efforts in the region.

有害藻华（HABs）对全球海洋生态系统和海产品安全构成日益严重的威胁，特别是在近岸水域。北部湾位于中国南海西北部，拥有丰富的生物多样性，是一个主要的渔区。为了全面了解藻毒素污染现状，我们于2021年8月进行了一项全流域的邮轮调查，收集了60份浮游植物样本，以表征12种目标海洋藻毒素的空间分布、组成剖面、分子来源及其主要环境驱动因素。藻毒素以软骨藻酸（DA）、果皮毒素-2 （PTX2）、同型叶裸毒素（homoYTX）、裸子二胺A （gymnodimine A）为主，冈田酸（OA）、藻毒素（DTX1）、叶裸毒素（YTX）偶有检出（检出率6.7%）。DA的检出率为20%（平均14424 pg L−1，最大163434 pg L−1），PTX2的检出率为36.7%（平均508 pg L−1，最大2995 pg L−1），homoYTX的检出率为43.3%（平均1717 pg L−1，最大42680 pg L−1），而gyma的检出率最高，为68.3%（平均37 pg L−1，最大902 pg L−1）。北部水域的藻毒素浓度明显高于南部海湾。元条形码鉴定出14种潜在产毒微藻，其中12种属于藻门。冗余分析表明，4种优势藻毒素浓度与溶解氧和叶绿素a呈正相关，与盐度呈负相关（p < 0.05）。这表明，陆地输入和海洋环流导致的低盐度（28−31）为产毒物种创造了有利的生态位。本研究阐明了北部湾藻毒素的分布及其推测的产毒微藻，同时强调了促进藻毒素产生的环境因素。这些发现为了解热带河口系统中有害藻华的动态提供了基础见解，有助于该地区未来的监测和管理工作。

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引用次数: 0

Impact of brewer’s spent grain on freshwater and marine harmful algal bloom species 啤酒废粮对淡水和海洋有害藻华的影响

IF 4.5 1区生物学 Q1 MARINE & FRESHWATER BIOLOGY

Harmful Algae

Pub Date : 2025-12-27 DOI: 10.1016/j.hal.2025.103047

C. Taylor Armstrong , Michael Gonsior , Allen R. Place

Barley straw bales are commonly used to control cyanobacterial growth in lakes, but the method is time-consuming, labor-intensive, and its effectiveness requires deployment of bales prior to bloom formation. This study investigates brewer’s spent grain (BSG), a byproduct of the brewing process, as an alternative source of allelopathic chemicals shown to negatively impact toxic microalgae. Water extracts of BSG, barley straw, and Sargassum natans were tested for their ability to inhibit the growth of toxin-producing (Microcystis aeruginosa and Karenia brevis) as well as non-toxin-producing (Tetradesmus obliquus and Phaeodactylum tricornutum) algal species. BSG extracts at concentrations above 250 mg/L effectively inhibited the growth of both freshwater and marine toxin-producing species (M. aeruginosa and K. brevis), while exhibiting no significant effect on the diatom and chlorophyte species tested (T. obliquus and P. tricornutum). Additional experiments using antibiotics with K. brevis suggest that growth inhibition may be mediated by changes in the bacterial community, though the specific mechanism of M. aeruginosa death remains unresolved. A microcosm experiment further evaluated the impact of BSG extract on a natural bloom of cyanobacteria (Raphidiopsis raciborskii) in lake water. Application of 250 mg/L BSG extract to natural lake water shifted the community composition from cyanobacteria to chlorophyte dominance. These findings highlight the potential use for a brewery’s waste product as a cost-effective tool for managing harmful algal blooms. However, the high concentrations required, excess nutrient content in BSG, and impact on bacterial communities indicate limitations for large-scale application.

大麦秸秆包通常用于控制湖泊中的蓝藻生长，但该方法耗时，劳动密集，其有效性需要在水华形成之前部署包。这项研究调查了啤酒酿造过程的副产品啤酒的废谷物（BSG），作为化感化学物质的替代来源，显示出对有毒微藻的负面影响。我们测试了BSG、大麦秸秆和马尾藻水提取物对产毒藻类（铜绿微囊藻和短Karenia brevis）和非产毒藻类（斜四角藻和三角褐藻）生长的抑制能力。浓度超过250 mg/L的BSG提取物可有效抑制淡水和海洋产毒物种（M. aeruginosa和K. brevis）的生长，而对硅藻和绿藻物种（T. obliquus和P. tricornutum）的生长无显著影响。使用抗生素对短克雷伯氏菌进行的其他实验表明，生长抑制可能是由细菌群落的变化介导的，尽管铜绿假单胞菌死亡的具体机制尚不清楚。通过微观实验进一步评估了BSG提取物对湖水中蓝藻（Raphidiopsis raciborskii）自然繁殖的影响。250mg /L BSG提取物在天然湖水中处理后，群落组成由蓝藻为主向绿藻为主转变。这些发现强调了啤酒厂废物作为一种经济有效的工具来管理有害藻华的潜在用途。然而，所需的高浓度、BSG中过量的营养含量以及对细菌群落的影响表明了大规模应用的局限性。

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引用次数: 0

Morphological and physiological adaptations of Dolichospermum flos-aquae to turbulence 水莲对湍流的形态和生理适应

IF 4.5 1区生物学 Q1 MARINE & FRESHWATER BIOLOGY

Harmful Algae

Pub Date : 2025-12-16 DOI: 10.1016/j.hal.2025.103046

Yulin Wang, Wenting Zhong, Ruiwen Chen, Qin Tang, Gongzheng Li, Zhou Yang, Yuan Huang

Heterocystous cyanobacteria are increasingly forming surface blooms in freshwater ecosystems, with massive proliferation events influenced by multiple environmental factors—among which turbulence has emerged as a pivotal driver. This study investigated the effects of different turbulence intensities (ranging from 10⁻⁵ to 10⁻² m² s⁻³, within the natural environmental range) on the morphology and physiology of the bloom-forming diazotroph Dolichospermum flos-aquae. Results showed that high-intensity turbulence promoted population growth, dissolved nitrogen uptake, and photosynthetic performance of D. flos-aquae. Under high turbulence conditions, filament length exhibited greater uniformity alongside an increase in average length. Furthermore, heterocyst production was markedly enhanced, with no alteration in the spatial localization of heterocysts along filaments. These phenotypic responses were associated with upregulated carbon and nitrogen metabolisms—particularly nitrogen assimilation and carbon fixation—supported by the increased expression of key functional genes. Collectively, these findings reveal the morphological and physiological adaptive strategies of heterocystous cyanobacteria to turbulent environments, thereby advancing our understanding of diazotrophic cyanobacterial bloom dynamics in hydrologically dynamic freshwater ecosystems.

在淡水生态系统中，异囊蓝藻越来越多地形成地表水华，其大规模增殖事件受到多种环境因素的影响，其中湍流已成为关键驱动因素。本研究研究了不同湍流强度（10−5 ~ 10−2 m2 s−3，在自然环境范围内）对重氮营养菌水藻（Dolichospermum flos-aquae）形态和生理的影响。结果表明，高强度湍流对水藻种群生长、溶氮吸收和光合性能有促进作用。在高湍流条件下，灯丝长度表现出更大的均匀性，同时平均长度增加。此外，杂种囊的产生明显增强，但杂种囊沿丝的空间定位没有改变。这些表型反应与碳氮代谢的上调有关，特别是氮同化和碳固定，并得到关键功能基因表达增加的支持。总的来说，这些发现揭示了异囊蓝藻对湍流环境的形态和生理适应策略，从而促进了我们对水文动态淡水生态系统中重氮营养蓝藻华动态的理解。

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引用次数: 0