Harmful Algae最新文献_第6页

A 20-year comparative study of domoic acid depuration in the king scallop, Pecten maximus, across French provinces 一项横跨法国各省的国王扇贝（Pecten maximus）中软骨藻酸净化的20年比较研究

IF 4.5 1区生物学 Q1 MARINE & FRESHWATER BIOLOGY

Harmful Algae

Pub Date : 2025-10-09 DOI: 10.1016/j.hal.2025.102995

Eline Le Moan , Amélie Derrien , Caroline Fabioux , Fred Jean , Malwenn Lassudrie , Aourégan Terre-Terrillon , Hélène Hégaret , Jonathan Flye-Sainte-Marie

Harmful Algal Blooms (HABs) can lead to fishery closures when toxin levels in commercial species exceed regulatory thresholds. Domoic acid (DA), the neurotoxin causing Amnesic Shellfish Poisoning (ASP), is particularly persistent in king scallops (Pecten maximus), a commercially valuable bivalve in France. This species is known for its slow depuration rate compared to other pectinids. This slow depuration rate allows for the calculation of DA dynamics, with the potential to better manage fishery openings in autumn, especially following spring contamination. This study used 20 years of data from the French phycotoxin in-situ monitoring program (REPHYTOX) to characterize decontamination episodes along the French Atlantic and English Channel coastlines. Depuration rates were estimated for 104 events; however, no correlation was found between depuration rate and province, time period, initial DA concentration or environmental conditions. From data, a median depuration rate was estimated and applied in a widely-used exponential decay model. In response to professionals’ needs, we developed a user-friendly predictive tool that estimates DA concentrations in king scallops based upon sampling in spring or summer. We recommend performing DA quantification in scallops whenever DA is detected in other shellfish at the same location, and running the predictive model to anticipate DA content at the opening of the fishery season in autumn. This tool will help fishery managers to anticipate bans, to avoid unnecessary license purchases, or to shift to alternative species. Although developed using French data, the methodology is adaptable to other regions with appropriate adjustments to reflect local ecological, regulatory, and fishery contexts.

当商业物种中的毒素水平超过监管阈值时，有害藻华（HABs）可能导致渔业关闭。软骨藻酸（DA）是一种引起失忆性贝类中毒（ASP）的神经毒素，在法国一种具有商业价值的双壳类贝类国王扇贝（Pecten maximus）中尤其持久存在。与其他果胶类动物相比，该物种以其缓慢的净化速度而闻名。这种缓慢的净化率使计算自然发展动态成为可能，从而更好地管理秋季的渔业开放，特别是在春季污染之后。这项研究使用了法国藻毒素原位监测项目（REPHYTOX） 20年来的数据，以表征法国大西洋和英吉利海峡沿岸的去污染事件。对104个事件的净化率进行了估计；而去除率与省份、时间、初始DA浓度和环境条件没有相关性。从数据中，估计了中位数净化率，并将其应用于广泛使用的指数衰减模型。为了满足专业人士的需求，我们开发了一种用户友好的预测工具，可以根据春季或夏季的采样来估计王扇贝中的DA浓度。我们建议在同一地点的其他贝类中检测到DA时，对扇贝进行DA量化，并在秋季渔业季节开始时运行预测模型来预测DA含量。该工具将帮助渔业管理者预测禁令，避免不必要的许可证购买，或转向替代物种。该方法虽然是利用法国的数据编制的，但也适用于其他地区，并作出适当调整，以反映当地的生态、管理和渔业情况。

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引用次数: 0

Economic impacts of sargassum events in Puerto Rico, USVI, and coastal Florida 马尾藻事件对波多黎各、美属维尔京群岛和佛罗里达沿海地区的经济影响

IF 4.5 1区生物学 Q1 MARINE & FRESHWATER BIOLOGY

Harmful Algae

Pub Date : 2025-10-04 DOI: 10.1016/j.hal.2025.102996

Di Jin , Avery Wang , Tracey Dalton

The frequency, intensity, and distribution of sargassum events have been rising in the Caribbean region in recent years causing social and economic disruptions. We develop estimates of the scale of annual economic impacts on local economies of sargassum events using multi-sector economic impact models for Puerto Rico, U.S. Virgin Islands, and coastal Florida. Using field observations from the Sargassum Watch database, we validate the current sargassum forecast in the region. We show that the forecast is performing well and that sargassum season has started earlier and lasted longer in recent years. The high-risk regions for sargassum inundation include Puerto Rico, U.S. Virgin Islands, and southeast coastal areas in Florida. Results of the study show that sargassum events are expected to cause significant negative economic impacts, in multimillion dollars each year, across the study regions, and the impact may be in billions of dollars along Florida’s Atlantic coast. These results provide important input to the planning process in deciding the investments in future sargassum response and cleanup. They can also facilitate targeted data collection and valuation efforts to develop more accurate measures of economic losses.

近年来，加勒比地区马尾藻事件的频率、强度和分布都在上升，造成社会和经济混乱。我们利用波多黎各、美属维尔京群岛和佛罗里达沿海的多部门经济影响模型，对马尾藻事件对当地经济的年度经济影响规模进行了估计。利用马尾藻观测数据库的现场观测，我们验证了该地区目前的马尾藻预测。我们表明，预测效果良好，马尾藻季节近年来开始得更早，持续时间更长。马尾藻淹没的高风险地区包括波多黎各、美属维尔京群岛和佛罗里达州的东南沿海地区。研究结果表明，马尾藻事件预计会对整个研究区域造成重大的负面经济影响，每年数百万美元，而佛罗里达州大西洋沿岸的影响可能高达数十亿美元。这些结果为决定未来马尾藻响应和清理的投资规划过程提供了重要的输入。它们还可以促进有针对性的数据收集和估值工作，以制定更准确的经济损失衡量标准。

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引用次数: 0

Mechanistic insights into Ginkgo-nerolidol compound preparation against the bloom-forming dinoflagellate Prorocentrum donghaiense 银杏神经醇复合制剂防治东海原鞭毛藻的机理研究

IF 4.5 1区生物学 Q1 MARINE & FRESHWATER BIOLOGY

Harmful Algae

Pub Date : 2025-10-02 DOI: 10.1016/j.hal.2025.102994

Anglu Shen , Aixue Qian , Wuyou Shen , Xinfeng Dai , Liu Shao

Prorocentrum donghaiense is a major bloom-forming species in the East China Sea and has severe adverse effects on marine ecosystems. To address this issue, the development of efficient and eco-friendly algal inhibitors is essential. However, research in this area remains limited. In this study, Ginkgo biloba extract (GB), nerolidol (NE), and a compound preparation (GN = GB + NE) were selected as algae-inhibiting materials, and the mechanisms of action of GB, NE, and GN on P. donghaiense were analyzed via RNA-seq. In total, 59,151, 152, and 25,363 differentially expressed genes (DEGs) were identified in algae treated with GB, NE, and GN, respectively. The top three GO- and KEGG-annotated DEGs were shared between GB and GN treatments, indicating that GB was the primary active component of GN. KEGG enrichment further showed that photosynthesis-related pathways were among the top five pathways affected by GN. Key genes in photosystem II (PsbA-E), cytochrome b₆/f complex (PetD), and ATP synthase (atpD) were downregulated, and 10 photosynthesis-antenna protein genes (Lhca1–4, Lhcb1–6) were upregulated under GN treatment. However, most of these genes did not show significant expression under the GB treatment, except for Lhca1 and Lhcb1–2. Furthermore, NE treatment upregulated ushA and downregulated pncC, disrupting algal nucleotide and NAD⁺ biosynthesis. This suggests that NE may accelerate GB-induced inhibition of photosynthesis-related pathways. These findings provide new insights into the molecular mechanisms underlying P. donghaiense exposure to GN and provide a theoretical basis for the prevention and control of harmful algal blooms.

东海原藻（proocentrum donghaiense）是东海主要的水华形成物种，对海洋生态系统有严重的不利影响。为了解决这一问题，开发高效、环保的藻类抑制剂至关重要。然而，这方面的研究仍然有限。本研究选择银杏叶提取物（GB）、神经樟醇（NE）和复合制剂（GN = GB + NE）作为抑藻材料，通过RNA-seq分析了GB、NE和GN对东海海螺的作用机制。总共鉴定出59,151、152和25,363个差异表达基因（deg），分别在GB、NE和GN处理的藻类中。GO和kegg注释的前3位DEGs在GB和GN处理中是相同的，表明GB是GN的主要活性成分。KEGG富集进一步表明，光合作用相关途径是受GN影响最大的5条途径之一。GN处理下，光系统II关键基因（PsbA-E）、细胞色素b6/f复合物（PetD）和ATP合成酶（atpD）下调，10个光合天线蛋白基因（Lhca1-4、Lhcb1-6）上调。除Lhca1和Lhcb1-2外，其余基因在GB处理下均无显著表达。此外，NE处理上调了ushA，下调了pncC，破坏了藻类核苷酸和NAD⁺的生物合成。这表明NE可能加速gb诱导的光合作用相关途径的抑制。这些发现为东海海螺暴露于GN的分子机制提供了新的认识，并为有害藻华的防治提供了理论依据。

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引用次数: 0

Two dueling Dolichospermum strains in an Oregon lake determine occurrence of cyanotoxic blooms 在俄勒冈州的一个湖泊中，两种相互斗争的水藻菌株决定了蓝藻毒华的发生

IF 4.5 1区生物学 Q1 MARINE & FRESHWATER BIOLOGY

Harmful Algae

Pub Date : 2025-09-30 DOI: 10.1016/j.hal.2025.102993

Theo W. Dreher , Connie S. Bozarth , Jonathan W. Shepardson , Norman L. Buccola , Ryan S. Mueller , Elijah Welch , Claudia S. Maier

There is a common perception that cyanobacterial harmful algal blooms (CyanoHABs) occur relatively consistently over consecutive years in a given lake or reservoir. Description of the CyanoHAB properties of a lake should thus be a useful managerial tool allowing the development of monitoring tools focused on problem cyanobacteria, particularly those producing cyanotoxins. We describe the characterization of CyanoHABs in Detroit Lake, Oregon, over a 12-year period. This time span encompassed two periods of relatively consistent CyanoHABs, but also a marked shift occurring between the two extended periods of stability. During 2012–2017, CyanoHABs in Detroit Lake consisted of short-lived (∼2 weeks) early-season blooms producing high levels of 7‑epi-cylindrospermopsin (CYN); very little microcystin (MC) was present. 2018 was a year in which levels of both CYN and MC were high, with MC produced from mid-May through July. During 2019–2024, MC concentrations were typically higher than CYN, and the early season CYN peaks were much lower than in previous years. Detroit Lake thus appears to have experienced two distinct periods of CyanoHAB character during the decade of study. We infer these changes to reflect changes in the dynamics of the two known cyanotoxin-producing Dolichospermum strains, Dolichospermum sp. DET 69 (CYN-positive) and Dolichospermum sp. DET73 (MC-positive), which appear to be the only significant cyanotoxin producers among the lake’s planktonic phytoplankton community. Occasional HABs dominated by nontoxigenic Aphanizomenon flos-aquae and Gloeotrichia echinulata were also a feature of the later years, although Dolichospermum spp. were the dominant cyanobacteria during most of the bloom season. This study illustrates how a lake’s CyanoHABs profile can change even in the absence of obvious changes in management or surrounding land use, and how an in-depth study of the CyanoHABs occurring in a lake over a few years can identify the problematical cyanobacteria and provide the information for developing a monitoring program targeting the HABs they produce.

有一个共同的看法，蓝藻有害藻华（CyanoHABs）发生相对一致连续多年在一个给定的湖泊或水库。因此，描述一个湖泊的蓝藻有害藻属性应该是一个有用的管理工具，允许开发监测工具，重点关注问题蓝藻，特别是那些产生蓝藻毒素的蓝藻。我们描述了在俄勒冈州底特律湖的蓝藻藻的特征，超过12年的时间。这段时间包含了两个相对一致的蓝藻藻华时期，但在两个延长的稳定时期之间也发生了显著的转变。在2012-2017年期间，底特律湖的蓝藻藻包括短暂的（约2周）早季华，产生高水平的7 -外柱精子素（CYN）；微量微囊藻毒素（MC）存在。2018年是CYN和MC水平都很高的一年，MC的生产时间从5月中旬到7月。2019-2024年MC浓度明显高于CYN， CYN季初峰值明显低于往年。因此，底特律湖在十年的研究中似乎经历了两个不同时期的蓝藻hab特征。我们推断这些变化反映了两种已知的产生蓝藻毒素的Dolichospermum菌株的动态变化，Dolichospermum sp. DET 69 （cyn阳性）和Dolichospermum sp. DET73 （mc阳性），这两种菌株似乎是湖泊浮游植物群落中唯一显著的蓝藻毒素产生者。偶尔的赤潮也以非产毒的水花藻（aphanizomenae - flos-aquae）和棘毛藻（Gloeotrichia echinulata）为主，尽管在大部分开花季节，Dolichospermum sp .是主要的蓝藻。本研究说明了即使在管理或周围土地利用没有明显变化的情况下，湖泊的蓝藻华概况如何发生变化，以及如何对湖泊中发生的蓝藻华进行深入研究，以确定有问题的蓝藻，并为制定针对它们产生的有害藻华的监测计划提供信息。

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引用次数: 0

Transcriptomic responses of toxic and non-toxic Microcystis aeruginosa to hydrogen peroxide and l-lysine treatments 有毒和无毒铜绿微囊藻对过氧化氢和赖氨酸处理的转录组反应

IF 4.5 1区生物学 Q1 MARINE & FRESHWATER BIOLOGY

Harmful Algae

Pub Date : 2025-09-29 DOI: 10.1016/j.hal.2025.102992

Elizabeth K. Dahedl , Taylor L. Hancock , Hidetoshi Urakawa

Microcystis aeruginosa is a ubiquitous, toxic, bloom-forming cyanobacterium found in freshwater ecosystems worldwide. In this study, we assessed two algaecidal mitigation methods (hydrogen peroxide and l-lysine) for the treatment of two toxic and two non-toxic strains of M. aeruginosa. Whole-transcriptome analysis with total RNA sequencing was used to assess the modes of action of these algaecides. We found both treatments led to increased transcriptional activity for genes associated with sulfur and cysteine pathways, which both support antioxidant enzyme activity. These regulatory mechanisms along with methionine metabolism were more enhanced for l-lysine treated strains, and may demonstrate a lack of l-lysine regulatory mechanisms and potential impact to the biosynthesis of other amino acids as well as intracellular sulfur recycling processes seen in transcription results. Toxic and non-toxic strains displayed a differential regulatory response to reduce oxidative stress levels. Two toxic strains downregulated the expression of microcystin biosynthesis genes and increased the expression of genes encoding antioxidant enzymes. Our results provide further support for the view that microcystins do not offer protection against high levels of oxidative stress. Production of microcystin may interfere with antioxidant enzyme functionality, and additionally, sulfur and cysteine demands for antioxidant enzymes likely outcompete their use for microcystin production under oxidative stress conditions. These findings can aid in the mitigation of toxin-producing M. aeruginosa blooms, suggesting high-dose hydrogen peroxide application has the potential to lower bloom toxicity through fast-acting impairment to microcystin gene synthetase expression as well as other metabolic functioning, likely lowering intracellular microcystin content, which may be released upon cell lysis after treatments. To our knowledge, the expression of microcystin synthetase genes after exposure to l-lysine has never been examined before. Seeing as this is a safe algaecide specifically targeting M. aeruginosa, this was another beneficial finding.

铜绿微囊藻是一种普遍存在的有毒蓝藻，存在于世界各地的淡水生态系统中。在这项研究中，我们评估了两种杀藻缓解方法（双氧水和赖氨酸）对两种有毒和两种无毒M. aeruginosa菌株的治疗。使用全转录组分析和总RNA测序来评估这些杀藻剂的作用方式。我们发现两种处理方法都增加了硫和半胱氨酸途径相关基因的转录活性，这两种途径都支持抗氧化酶的活性。这些调节机制以及蛋氨酸代谢在l-赖氨酸处理菌株中得到了更强的增强，这可能表明缺乏l-赖氨酸调节机制，并可能影响转录结果中其他氨基酸的生物合成以及细胞内硫循环过程。有毒和无毒菌株对降低氧化应激水平表现出不同的调节反应。两株毒株微囊藻毒素合成基因表达下调，抗氧化酶编码基因表达上调。我们的研究结果进一步支持了微囊藻毒素不能抵抗高水平氧化应激的观点。微囊藻毒素的产生可能会干扰抗氧化酶的功能，此外，在氧化应激条件下，硫和半胱氨酸对抗氧化酶的需求可能会超过它们对微囊藻毒素产生的使用。这些发现有助于减轻产生毒素的M. aeruginosa华，表明高剂量过氧化氢应用有可能通过对微囊藻毒素基因合成酶表达的速效损伤以及其他代谢功能来降低华毒性，可能降低细胞内微囊藻毒素含量，这些含量可能在处理后细胞裂解时释放出来。据我们所知，暴露于l-赖氨酸后微囊藻毒素合成酶基因的表达从未被检测过。鉴于这是一种专门针对绿脓杆菌的安全杀藻剂，这是另一个有益的发现。

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引用次数: 0

Comparative toxicity of Karlodinium veneficum from France and New Zealand on fish gill cells and oyster gametes 法国和新西兰产卡罗迪菌对鱼鳃细胞和牡蛎配子的毒性比较

IF 4.5 1区生物学 Q1 MARINE & FRESHWATER BIOLOGY

Harmful Algae

Pub Date : 2025-09-29 DOI: 10.1016/j.hal.2025.102991

Anne Rolton , Guillaume Barnouin , Hannah Greenhough , Audrey Duval , Karthiga Kumanan , Nelly Quéré Le Goïc , Lucy Thompson , Damien Réveillon , Fabienne Hervé , Andrew I. Selwood , Hélène Hégaret , Kirsty F. Smith , Malwenn Lassudrie

Harmful algal blooms (HABs) can cause mass mortalities of marine fauna, leading to major economic losses in aquaculture and fisheries worldwide. Toxicity varies widely among strains of the same HAB species, making broad assumptions of toxicity inaccurate. This study investigated the ichthyotoxic activity of Karlodinium veneficum, a HAB species of risk for aquaculture in France (FR) and New Zealand (NZ). Five K. veneficum strains (3 FR, 2 NZ) were cultured and extracted under standardized conditions. Following inter-laboratory assay comparison, crude (culture) and methanolic intra- and extracellular extracts were tested on in vitro models: rainbow trout gill cells (RTgill-W1) and Pacific oyster, Crassostrea (=Magallana) gigas, sperm.

Crude and methanolic extracts showed toxicity to both cell types, with variation between intra- (IN) and extracellular (EX) fractions. Of the crude extracts, only CAWD93 IN was toxic to gill and sperm cells, inducing 44 % and 81 % mortality, respectively, at 8.75 × 10⁴ equiv. cells mL^-1. Most methanolic extracts were toxic; MAR1F7 EX and CAWD93 IN induced the highest mortality rates, with EC₅₀’s reaching cell concentrations equivalent to high environmental bloom levels.

Karlotoxin analysis of methanolic extracts revealed distinct profiles by country. Karlotoxins were detected only in the three most toxic strains (MAR1F7, IFR-CC-20-44, CAWD93) and cytotoxicity was only weakly correlated with karlotoxin concentration, suggesting involvement of additional toxic compounds.

This study highlights strain-specific toxicity in K. veneficum, underscoring the importance of testing local HAB strains. The bioassays used offer a rapid, cost-effective, high-throughput, and ethical approach to evaluating HAB toxicity—crucial as ichthyotoxic blooms become more frequent globally.

有害藻华（HABs）可导致海洋动物大量死亡，给全世界的水产养殖和渔业造成重大经济损失。同一HAB物种的毒株之间毒性差异很大，使得毒性的广泛假设是不准确的。本研究调查了法国和新西兰水产养殖中存在危险的赤潮有害生物Karlodinium veneficum的鱼毒活性。在标准化条件下，培养并提取了5株veneficum菌株（3株FR， 2株NZ）。经过实验室间的分析比较，在体外模型：虹鳟鱼鳃细胞（RTgill-W1）和太平洋牡蛎、长牡蛎（=Magallana） gigas、精子上测试了粗（培养）和甲醇细胞内和细胞外提取物。粗提取物和甲醇提取物对两种细胞都有毒性，但细胞内（IN）和细胞外（EX）组分之间存在差异。在粗提物中，只有CAWD93 IN对鳃细胞和精子细胞有毒性，在8.75 × 104等量细胞mL-1时，分别诱导44%和81%的死亡率。大多数甲醇提取物是有毒的；MAR1F7 EX和CAWD93 IN诱导的死亡率最高，EC50达到相当于高环境华水平的细胞浓度。甲醇提取物的Karlotoxin分析显示了不同国家的不同特征。仅在3株毒性最强的菌株（MAR1F7、IFR-CC-20-44、CAWD93）中检测到karlotoxin，细胞毒性与karlotoxin浓度仅呈弱相关，提示涉及其他毒性化合物。这项研究强调了菌株特异性毒性，强调了检测当地HAB菌株的重要性。所使用的生物测定方法提供了一种快速、成本效益高、高通量和合乎伦理的方法来评估赤潮毒素的毒性——随着全球范围内鱼毒性水华变得越来越频繁，这一点至关重要。

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引用次数: 0

Why do some dinoflagellates produce toxins, whereas ciliates rarely do? 为什么有些鞭毛动物会产生毒素，而纤毛虫却很少？

IF 4.5 1区生物学 Q1 MARINE & FRESHWATER BIOLOGY

Harmful Algae

Pub Date : 2025-09-27 DOI: 10.1016/j.hal.2025.102988

Albert Calbet

Dinoflagellates and ciliates dominate marine microzooplankton, yet widespread toxin production is largely restricted to dinoflagellates. This perspective synthesizes evolutionary, genomic, and ecological drivers of that asymmetry with direct relevance to harmful algal events. From a molecular and biochemical point of view, dinoflagellates possess vast, repeat-rich genomes that support modular PKS/NRPS pathways yielding chemically diverse metabolites, whereas ciliates generally lack complete PKS/NRPS clusters (apart from a few predatory lineages) and instead emphasize behavioral defenses and rapid reproduction. Most confirmed toxic dinoflagellates are photosynthetic or mixotrophic; robust cases in purely heterotrophic taxa are lacking. Despite environment-dependent costs, dinoflagellate metabolites confer grazer deterrence, allelopathy, prey lysis, and potential nutrient acquisition. Socio-economically, paralytic shellfish toxins (saxitoxins) produced by Alexandrium spp., Gymnodinium catenatum, and Pyrodinium bahamense—non-PKS alkaloids associated with sxt genes—are among the most consequential. An integrated approach coupling genomics, metabolomics, targeted bioassays, and in situ observations will clarify when chemical versus behavioral strategies prevail across ocean regimes, thereby improving HAB risk assessment, monitoring, and mitigation.

鞭毛纲和纤毛虫是海洋微型浮游动物的主要动物，但广泛的毒素生产主要局限于鞭毛纲。这种观点综合了与有害藻类事件直接相关的不对称的进化、基因组和生态驱动因素。从分子和生物化学的角度来看，鞭毛虫拥有大量的、重复丰富的基因组，支持模块化的PKS/NRPS途径，产生化学上多样化的代谢物，而纤毛虫通常缺乏完整的PKS/NRPS集群（除了少数掠食性分支），而是强调行为防御和快速繁殖。大多数已证实的有毒鞭毛藻是光合或混合营养型的；在纯异养分类群中缺乏可靠的病例。尽管环境依赖的成本，鞭毛藻代谢物赋予食草动物威慑，化感作用，猎物裂解和潜在的营养获取。社会经济方面，由Alexandrium spp.、Gymnodinium catenatum和Pyrodinium bahameni产生的麻痹性贝类毒素（蛤毒素）——与sst基因相关的非pks生物碱——是最重要的。将基因组学、代谢组学、靶向生物测定和现场观察相结合的综合方法将澄清化学策略与行为策略在整个海洋环境中何时占上风，从而改进有害藻华风险评估、监测和缓解。

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引用次数: 0

Possible accumulation of harmful flagellates caused by interaction between vertical swimming and upper ocean turbulence 垂直游泳与上层海洋湍流的相互作用可能造成有害鞭毛虫的积聚

IF 4.5 1区生物学 Q1 MARINE & FRESHWATER BIOLOGY

Harmful Algae

Pub Date : 2025-09-26 DOI: 10.1016/j.hal.2025.102990

Goh Onitsuka , Yutaka Yoshikawa

In the natural oceanic environment, microalgae occasionally form blooms with rates of increase that exceed their growth rates observed under laboratory conditions. We hypothesized that these elevated rates result from the accumulation caused by the combined effects of vertical swimming behavior and physical processes in the upper ocean. To test this hypothesis, we conducted numerical experiments using a Lagrangian particle-tracking model coupled with a hydrodynamic model. In a stratified ocean forced by sea surface winds and waves, we released particles simulating three fish- and shellfish-killing flagellates with different swimming speeds, namely Chattonella marina complex, Karenia mikimotoi, and Margalefidinium polykrikoides. Due to the interplay of diel vertical migration (DVM) and upper ocean turbulence, the particles accumulated vertically, exhibiting peak concentrations in the surface layer in the afternoon. These concentrations were several times higher than those observed at night or in the morning. Strong turbulence resulting from high wind speeds reduced surface accumulation and altered the depth of the maximum particle concentration compared to the still-water case (i.e., DVM only), especially for the slow-swimming Chattonella. Under low wind speeds (U₁₀ = 1.5–2.0 m s⁻¹), particles simulating the fast-swimming M. polykrikoides horizontally accumulated in streaks where surface flow converged, increasing particle concentration by up to one order of magnitude. This horizontal accumulation was caused by the balance between the upward swimming speed of M. polykrikoides and the downwelling associated with horizontal convergence driven by Langmuir circulations. Compared to algal growth, these vertical and horizontal accumulation processes occurred over shorter timescales, highlighting the importance of considering accumulation in monitoring harmful algal blooms.

在自然海洋环境中，微藻偶尔会形成水华，其增长速度超过在实验室条件下观察到的生长速度。我们假设这些升高的速率是由垂直游泳行为和上层海洋物理过程的综合影响引起的积累造成的。为了验证这一假设，我们使用拉格朗日粒子跟踪模型和流体动力学模型进行了数值实验。在受海面风和海浪影响的分层海洋中，我们释放了模拟三种不同游泳速度的杀死鱼类和贝类的鞭毛虫的粒子，即Chattonella marina complex， Karenia mikimotoi和Margalefidinium polykrikoides。由于日向垂直迁移（DVM）和上层海洋湍流的相互作用，颗粒垂直积累，下午在表层达到峰值。这些浓度比夜间或早晨观察到的浓度高几倍。与静水情况（即仅DVM）相比，由高风速引起的强湍流减少了表面积聚并改变了最大颗粒浓度的深度，特别是对于缓慢游动的查通菌。在低风速条件下（U10 = 1.5-2.0 m s−1），模拟快速游动的多角粒藻颗粒水平聚集成条状，使表面水流汇聚，颗粒浓度增加了一个数量级。这种水平积累是由多角藻的向上游动速度与Langmuir环流驱动的水平辐合下移之间的平衡造成的。与藻类生长相比，这些垂直和水平积累过程发生在更短的时间尺度上，突出了在监测有害藻华时考虑积累的重要性。

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引用次数: 0

Unique distribution pattern of Aureococcus anophagefferens in the Yellow Sea during late summer influenced by complex hydrodynamics and green tide decomposition 受复杂水动力和绿潮分解的影响，夏末黄海嗜食金黄色球菌的独特分布模式

IF 4.5 1区生物学 Q1 MARINE & FRESHWATER BIOLOGY

Harmful Algae

Pub Date : 2025-09-24 DOI: 10.1016/j.hal.2025.102987

Lu Sun , Huixia Geng , Qingchun Zhang , Zhenfan Chen , Chao Liu , Fanzhou Kong , Rencheng Yu

Since 2009, brown tide-causing pelagophyte Aureococcus anophagefferens has recurrently impacted northern Chinese coastal waters. Previous observations suggest elevated abundances of A. anophagefferens occur in specific regions of the Yellow Sea (YS) where the decomposition of Ulva prolifera green tides during late summer, implying supportive role on its growth for green algae decomposition. However, the complex hydrodynamic processes in these areas complicate the disentanglement of the effects of green tide decomposition and hydrodynamic influences. In this study, quantitative PCR and environmental analyses were employed to examine the spatial distribution, interannual variations, and environmental drivers of A. anophagefferens during late summers in 2016, characterized by a high-intensity green tide, and 2017, marked by a low-intensity green tide. A. anophagefferens exhibited a vertically spindle-shaped distribution with peak cell densities at the deep chlorophyll maximum layer, primarily along the Shandong Peninsula and in the eastern YS. Notably, cell abundances in 2016 were significantly higher than those in 2017, linking to increased ammonium, phosphate, and dissolved organic matter resulting from green tide decomposition. Hydrodynamic factors, especially temperature stratification and the Yellow Sea Bottom Cold Water, appeared to significantly affect the distribution of A. anophagefferens. The enhanced nutrient release during the large-scale green tide event in 2016 further promoted the growth of A. anophagefferens, highlighting the link between green tide events and the emergence of other harmful algal blooms in northern Chinese coastal waters.

自2009年以来，褐色致潮藻嗜食金黄色葡萄球菌（Aureococcus anophagefferens）反复影响中国北部沿海水域。先前的观察表明，在黄海（YS）的特定区域，在夏末繁殖藻绿潮分解的地方，anophagefferens的丰度升高，这意味着它对绿藻分解的生长有支持作用。然而，这些地区复杂的水动力过程使绿潮分解和水动力影响的影响变得复杂。本研究采用定量PCR和环境分析相结合的方法，研究了2016年夏末绿潮强度高、2017年夏末绿潮强度低的食蚜螨的空间分布、年际变化及其环境驱动因素。呈垂直纺锤形分布，细胞密度峰值出现在叶绿素最高层深处，主要分布在山东半岛和东洋。值得注意的是，2016年的细胞丰度显著高于2017年，这与绿潮分解导致的铵、磷酸盐和溶解有机质增加有关。水动力因素，特别是温度分层和黄海底部冷水对无食棘球绦虫的分布有显著影响。2016年大规模绿潮事件期间，营养物质释放增强，进一步促进了嗜食A. anophagefferens的生长，凸显了绿潮事件与中国北方沿海其他有害藻华的出现之间的联系。

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引用次数: 0

Dynamics of harmful algal bloom species are independent of the extent of the Changjiang Diluted Water Intrusion Off Western Jeju Island in the Northern East China Sea 东海北部济州岛西部海域有害藻华种类动态与长江稀释水入侵程度无关

IF 4.5 1区生物学 Q1 MARINE & FRESHWATER BIOLOGY

Harmful Algae

Pub Date : 2025-09-24 DOI: 10.1016/j.hal.2025.102986

Yeongji Oh , Min-Sun Lee , Eunbi Lee , Chan-Woo Kwon , Minji Lee , Ho Young Soh , Yoonja Kang

The western Jeju Island region, located on the continental shelf of the northern East China Sea, is influenced by Changjiang Diluted Water (CDW), Yellow Sea Bottom Cold Water, and branches of Kuroshio Current. Due to its proximity to the South Sea of Korea, an area historically subject to annual harmful algal blooms (HABs) but experiencing a recent decline in bloom frequency, we investigated variations in the HAB species occurrence during the CDW intrusion in June 2022 and 2023, when the extent of CDW intrusion drastically differed. Additionally, current flows from the study region toward the South Sea were investigated using a data-assimilative ocean circulation model that integrated multiple satellite and in situ observations. Microscopy and 18S rRNA sequencing analyses and photosynthetic efficiency measurements using Phyto-PAM II revealed that more CDW intrusion increased nutrient stress for diatoms and dinoflagellates, mainly due to extreme phosphorus limitation. However, HAB species such as Pseudo-nitzschia spp. rapidly responded to increased nitrogen availability. In contrast, reduced CDW intrusion mitigated nutrient stress caused by imbalanced stoichiometry, and small-sized HAB species, including Aureococcus anophagefferens, Karlodinium veneficum, Prorocentrum obtusidens dominated under conditions of the DOP availability and light-limitation. Furthermore, ocean current simulations showed strong flows toward the southern coastal waters of Korea during summer. Collectively, our findings suggest that, regardless of the extent of CDW inflow, different types of HAB species can be developed in western Jeju, and ocean currents potentially transport them to the South Sea of Korea.

济州岛西部地区位于东海北部大陆架，受长江稀释水、黄海底冷水和黑潮分支的影响。由于靠近韩国南海，该地区历史上每年都会发生有害藻华（HABs），但近年来爆发频率有所下降，因此我们研究了2022年6月和2023年6月CDW入侵期间HAB物种发生的变化，当时CDW的入侵程度存在显著差异。此外，利用综合多颗卫星和现场观测的数据同化海洋环流模式研究了研究区向南海的洋流。显微镜和18S rRNA测序分析以及利用phytoto - pam II进行的光合效率测量显示，更多的CDW入侵增加了硅藻和鞭毛藻的营养胁迫，这主要是由于极端的磷限制。然而，伪尼茨氏菌等HAB物种对氮有效性的增加反应迅速。相比之下，CDW入侵的减少减轻了化学不平衡造成的营养胁迫，在DOP有效度和限光条件下，小型HAB物种占主导地位，包括厌食金黄色葡萄球菌（Aureococcus anophagefferens）、veneficum、proorocentrum obtusidens。此外，洋流模拟显示夏季朝韩国南部沿海水域有强流。总的来说，我们的研究结果表明，无论CDW流入的程度如何，济州西部都可能发展出不同类型的有害藻华物种，并且洋流可能将它们运送到韩国南海。

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引用次数: 0