Harmful Algae最新文献_第7页

Diversity of amphidomatacean dinoflagellates in Japan, with a description of Azadinium inconspicuum sp. nov. and azaspiracid components in Azadinium poporum ribotypes 日本甲藻类双鞭毛藻的多样性，包括Azadinium inum sp. 11 .和Azadinium poporum核型中Azadinium的成分

IF 4.5 1区生物学 Q1 MARINE & FRESHWATER BIOLOGY

Harmful Algae

Pub Date : 2025-09-09 DOI: 10.1016/j.hal.2025.102969

Koyo Kuwata , Wai Mun Lum , Kazuya Takahashi , Garry Benico , Mayu Ozawa , Hajime Uchida , Satoshi Numano , Ryuichi Watanabe , Ryoji Matsushima , Toshiyuki Suzuki , Mitsunori Iwataki

Species diversity of amphidomatacean dinoflagellates belonging to Azadinium and Amphidoma was examined by microscopic observation and ITS- and LSU rDNA-based phylogeny, using 81 culture strains and two uncultured cells from Japanese waters during 2016–2024. In total, 11 species were found in Japanese waters. Of these, Azadinium caudatum, Az. cuneatum, Az. dexteroporum, and Az. spinosum were newly found in the Northwest Pacific, Az. dalianense was the first report in Japan, and Azadinium inconspicuum sp. nov. was a new species described in this study. Azadinium inconspicuum independently branched in the clade of Az. dexteroporum/Az. galwayense/Az. perfusorium but differed from Az. dexteroporum in shape of the Po plate (absent vs. present of the finger-like protrusion), from Az. galwayense in shape of the 2a plate (four- vs. five-sided), and from Az. perfusorium in position of pyrenoid (in the episome vs. at the antapex). It had a close resemblance to Az. luciferelloides in thecal morphology, but differed in detailed position of the ventral pore and shape of the posterior sulcal plate. Azaspiracids (AZAs) were detected in Azadinium poporum and Az. spinosum, but no trace was found in other amphidomatacean cultures, including Az. dexteroporum. Among 81 cultures examined, 47 cultures were assigned to Az. poporum, and belonged to four intraspecific ribotypes. Major AZA components in Japanese Az. poporum strains were AZA-59 (ribotype A1), AZA-2 (ribotype A2), AZA-2, -11, -36, -40 (ribotype B), and AZA-2 (ribotype C1). These results suggested that Az. poporum, particularly in ribotype C1, where high AZA amounts were detected, is the major AZA-producer along the Japanese coastal waters.

以2016-2024年日本海域的81株培养菌株和2个未培养细胞为研究对象，采用显微镜观察和ITS- LSU rdna系统发育研究了Azadinium和Amphidoma两种双鞭毛纲甲藻的物种多样性。在日本海域共发现了11种。其中尾状Azadinium caudatum、cuneatum、dexteroporum和spinosum为西北太平洋新发现的Azadinium， dalalianense为日本首次报道的Azadinium， inactuum sp. 11 .为本文报道的新种。Azadinium in在Az. dexteroporum/Az的分支中独立分支。galwayense /阿兹。但在Po板的形状（无指状突起与有指状突起）、2a板的形状（四面与五面）和类pyrenoid的位置（在尾端与前端）上与azs . perusorium不同。它在鞘形态上与紫斑虫相似，但在腹侧孔的详细位置和后沟板的形状上存在差异。在popadinium spinosum和Azadinium spinosum中检测到氮氮酸（AZAs），但在其他两栖动物培养物（包括Azadinium dexteroporum）中未发现氮氮酸（AZAs）。在81个培养物中，47个培养物归属于阿兹兰，属于4种种内核糖型。日本流行疫病毒主要AZA成分为AZA-59 （A1型）、AZA-2 （A2型）、AZA-2、-11、-36、-40 （B型）和AZA-2 （C1型）。这些结果表明，在日本沿海水域，特别是在检测到高AZA量的C1核型中，poporum是AZA的主要生产者。

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引用次数: 0

Simplifying marine biotoxin data analysis: Advancing the Neuro-2a cell-based assay using R 简化海洋生物毒素数据分析：使用R推进基于神经2a细胞的测定

IF 4.5 1区生物学 Q1 MARINE & FRESHWATER BIOLOGY

Harmful Algae

Pub Date : 2025-09-05 DOI: 10.1016/j.hal.2025.102968

Synne T. Frøstrup , Christian Ritz , Oliver Kappenstein , Astrid Spielmeyer , Christopher R. Loeffler

Marine biotoxins (MBs) pose a significant public health risk as seafood contaminants. Testing seafood for MBs before consumption can protect consumers and further provide quality assurances. The in vitro Neuro-2a (N2a) cell-based assay (CBA), is a sensitive, high-throughput, and cost-effective method for the semi-quantification of MBs such as ciguatoxins (CTXs) and brevetoxins (PbTxs), serving as an alternative to animal-based testing. However, the N2a CBA has not been validated, limiting its utility. High data variability based on several potential sources including inter-software inconsistencies, data transfer errors, and improper data processing (calculation errors), or handling (dealing with missing, corrupted, or inconsistent data), have been cited as major challenges to the method. Data errors or inaccuracies can disrupt data integrity and lead to false positive or negative results, with serious health implications. To address these issues, a customized R package, n2a, was developed as the first standardized and free data analysis operating procedure for the N2a CBA. It is designed for simultaneous dose-response analysis of assay derived data and displays parameter estimates, calculates effective concentration (EC₅₀), and generates high-quality graphical outputs. The n2a package ensures rapid dose-response model fitting for larger datasets (2 s per dataset) compared to traditional software (3 min per dataset), increasing data processing efficiency and reducing the potential for data handling errors.

海洋生物毒素作为海产品污染物，对公众健康构成重大威胁。在食用海产品前检测MBs，可以保护消费者，并进一步提供质量保证。体外基于神经2a （N2a）细胞的检测（CBA）是一种灵敏、高通量、经济高效的半定量方法，可作为动物实验的替代方法，用于卡卡毒素（CTXs）和短链毒素（PbTxs）等MBs。然而，N2a CBA尚未得到验证，限制了它的实用性。基于软件间不一致、数据传输错误和不当数据处理（计算错误）或处理（处理丢失、损坏或不一致的数据）等几个潜在来源的高数据可变性被认为是该方法面临的主要挑战。数据错误或不准确会破坏数据完整性，导致假阳性或假阴性结果，对健康造成严重影响。为了解决这些问题，开发了定制的R包n2a，作为n2a CBA的第一个标准化和免费的数据分析操作程序。它被设计用于同时剂量-反应分析测定数据和显示参数估计，计算有效浓度（EC50），并产生高质量的图形输出。与传统软件（每个数据集3分钟）相比，n2a包确保了更大数据集的快速剂量反应模型拟合（每个数据集2秒），提高了数据处理效率并减少了数据处理错误的可能性。

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引用次数: 0

Combined effects of CO2 and nitrogen on the stoichiometry of toxin synthesis in a harmful cyanobacterium CO2和氮对有害蓝藻毒素合成化学计量学的联合影响

IF 4.5 1区生物学 Q1 MARINE & FRESHWATER BIOLOGY

Harmful Algae

Pub Date : 2025-09-04 DOI: 10.1016/j.hal.2025.102964

Savannah Sarkis , Jing Liu , Jef Huisman , Uwe John , Jolanda M.H. Verspagen , Dedmer B. Van de Waal

The increase in frequency and intensity of harmful cyanobacterial blooms in freshwater ecosystems over past decades has been attributed to anthropogenic influence, notably eutrophication and climate change. Microcystis is among the most widespread cyanobacterial bloom-forming genera, some strains of which can produce a range of microcystin variants having different toxicities. The synthesis of microcystins (MCs) is closely linked to carbon and nitrogen metabolism as microcystin variants differ in their nitrogen:carbon ratio. Thus, changes in availability of both CO₂ and nitrogen may impact microcystin production and composition. While the separate effects of CO₂ and nitrogen have been documented, their combined effect is less understood. We therefore assessed the effects of a CO₂ gradient at both nitrogen-replete and -deplete conditions on cellular nitrogen and carbon contents, N:C stoichiometry and microcystin synthesis in three Microcystis aeruginosa strains. We observed an interactive effect of increasing CO₂ concentrations with nitrogen availability across strains. Specifically, with increasing CO₂ availability, cellular N:C stoichiometry decreased under nitrogen-deplete conditions from 0.14 to 0.07 but increased under nitrogen-replete conditions from 0.11 to 0.17. Although total cellular microcystin content remained largely unaffected by both CO₂ and nitrogen despite shifts in N:C stoichiometry, changes in variant composition were consistent across strains and followed a stoichiometrically predictable pattern. N-rich but less toxic microcystin variants were favored at high cellular N:C ratios (e.g. MC-RR reached up to 44 % of total MC at highest N:C ratios), whereas relatively less N-containing but more toxic variants became more prevalent at low N:C ratios (e.g. MC-LW shifted from 9 % to 36 % of total MC for one of the strains). This study shows that shifts in CO₂ and nitrogen availability affect cellular N:C stoichiometry and alter microcystin composition, which may cause changes in the toxicity of cyanobacterial blooms.

过去几十年来，淡水生态系统中有害蓝藻爆发的频率和强度增加归因于人为影响，特别是富营养化和气候变化。微囊藻是最广泛的蓝藻属之一，其中一些菌株可以产生一系列具有不同毒性的微囊藻毒素变体。微囊藻毒素（microcystin, MCs）的合成与碳氮代谢密切相关，因为微囊藻毒素变体的氮碳比不同。因此，二氧化碳和氮可用性的变化可能会影响微囊藻毒素的产生和组成。虽然二氧化碳和氮的单独影响已被记录在案，但它们的综合影响却鲜为人知。因此，我们评估了在充氮和缺氮条件下CO2梯度对三种铜绿微囊藻菌株细胞氮和碳含量、氮碳化学计量和微囊藻毒素合成的影响。我们观察到CO2浓度的增加与菌株间氮有效性的相互作用。具体来说，随着CO2有效性的增加，细胞N:C化学计量在缺氮条件下从0.14下降到0.07，而在充氮条件下从0.11上升到0.17。尽管细胞微囊藻毒素的总含量在很大程度上不受CO2和氮的影响，尽管N:C的化学计量变化，变异成分的变化在菌株之间是一致的，并遵循化学计量可预测的模式。在高细胞N:C比下，富氮但毒性较低的微囊藻毒素变异更受青睐（例如，在最高N:C比下，MC- rr达到总MC的44%），而在低N:C比下，相对含氮较少但毒性较强的微囊藻毒素变异更普遍（例如，MC- lw从其中一个菌株的总MC的9%转移到36%）。该研究表明，CO2和氮有效性的变化会影响细胞N:C化学计量，并改变微囊藻毒素的组成，这可能导致蓝藻华毒性的变化。

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引用次数: 0

Ship-based eDNA tracking unveils early dispersal patterns and microecological dynamics of Ulva prolifera micropropagules in yellow sea green tide outbreaks 基于船舶的eDNA追踪揭示了黄海绿潮爆发时增生Ulva微繁殖体的早期扩散模式和微生态动态

IF 4.5 1区生物学 Q1 MARINE & FRESHWATER BIOLOGY

Harmful Algae

Pub Date : 2025-09-03 DOI: 10.1016/j.hal.2025.102966

Runze Chen , Yinqing Zeng , Caihua Yao , Faqing He , Shulin Tan , Yutao Qin , Huanhong Ji , Lihua Xia , Lining Xia , Yuru Yan , Peimin He , Jianheng Zhang

Green tides caused by Ulva prolifera in the South Yellow Sea (SYS) pose significant ecological and economic threats. Neopyropia aquaculture rafts in the Subei Shoal are considered to be the main source of green tides in the SYS, where micropropagules are the ‘Seed Bank’ for green tides. But the early dynamics of the U. prolifera remain unclear due to the limitations of conventional monitoring methods. This study systematically investigated the spatiotemporal distribution characteristics and key environmental driving mechanisms of environmental DNA (eDNA) from U. prolifera in development areas of Yellow Sea green tide, using eDNA technology combined with environmental parameters. Surveys in April and June 2024 across Neopyropia raft-farming (RD transect) and non-raft (SY transect) areas revealed ecological differences during early green tide development. Key findings include:(1) In April, U. prolifera eDNA abundance in RD exhibited a "high near rafts, low farther away" distribution, regulated by temperature and total nitrogen, while SY followed similar trends driven primarily by temperature. No environmental factors were found to be significantly correlated with the distribution of U. prolifera eDNA in June. (2) High U. prolifera eDNA abundance at SY4 in April was driven by hydrodynamics (tidal asymmetry), temperature, and biological interactions (e.g., Cercozoa), identifying a hotspot for monitoring. (3) Raft-farming areas exhibited stronger species interactions, with Chlorophyta and Cercozoa closely linked to U. prolifera. The identification of Pirsonia sp. and other species provides a new perspective for elucidating the competitive mechanisms underlying early-stage U. prolifera outbreaks and for developing early biological control strategies against green tides. This study provides molecular ecological evidence for analyzing the aggregation driving mechanism of the development areas of early green tide in the SYS, highlights the utility of eDNA in monitoring, and offers theoretical support for marine ecosystem management under climate change.

南黄海由藻藻引起的绿潮对生态和经济造成了严重威胁。苏北浅滩的新异位养殖筏被认为是SYS绿潮的主要来源，其中微繁殖体是绿潮的“种子库”。但由于常规监测方法的限制，美国核扩散的早期动态仍不清楚。本研究采用eDNA技术结合环境参数，系统研究了黄海绿潮发育区多刺藻环境DNA （environmental DNA, eDNA）的时空分布特征及关键环境驱动机制。2024年4月和6月的调查显示，在绿潮形成早期，新冠藻木筏养殖区（RD样带）和非木筏养殖区（SY样带）存在生态差异。主要发现包括：(1)4月，黑龙江地区浒苔eDNA丰度表现出“近筏高，远筏低”的分布规律，受温度和总氮的调节，而黑龙江地区则主要受温度的影响。6月份，环境因子与浒苔eDNA的分布无显著相关。(2) 4月SY4区增殖U. U. prolifera eDNA丰度高，受水动力（潮汐不对称）、温度和生物相互作用（如尾虫）驱动，是监测热点。(3)筏养区物种间的相互作用较强，绿藻和尾藻与藻间的相互作用密切相关。Pirsonia sp.和其他物种的鉴定为阐明早期繁殖U.爆发的竞争机制和制定针对绿潮的早期生物控制策略提供了新的视角。本研究为分析南海早期绿潮发育区域聚集驱动机制提供了分子生态学证据，突出了eDNA在监测中的应用，为气候变化下的海洋生态系统管理提供了理论支持。

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引用次数: 0

Sub-lethal effects of natural cyanobacterial blooms on fish: Enzymatic activity and swimming performance in Gasterosteus aculeatus 天然蓝藻华对鱼类的亚致死效应：鱼的酶活性和游泳性能

IF 4.5 1区生物学 Q1 MARINE & FRESHWATER BIOLOGY

Harmful Algae

Pub Date : 2025-09-03 DOI: 10.1016/j.hal.2025.102965

Francesco Masnadi , Xuewei Qi , John M. Taylor , Joachim Sturve , Valentina Di Santo , Agnes M.L. Karlson

Cyanobacterial blooms are intensifying worldwide due to eutrophication and climate change, increasing cyanotoxin exposure to aquatic organisms. This study investigated the physiological, biochemical, and behavioural impacts of cyanobacterial blooms on the three-spined stickleback (Gasterosteus aculeatus), a widespread mesopredatory fish. Adult sticklebacks were exposed for two weeks to naturally collected bloom material dominated by toxic Nodularia spumigena, non-toxic Aphanizomenon sp., or a 50:50 mix. We measured toxin accumulation (NOD_eq), hepatic enzymatic activities (ethoxyresorufin-O-deethylase [EROD], glutathione S-transferases [GSTs], glutathione reductase [GR], and catalase [CAT]), and escape swimming performance (centre-of-mass velocity, angular velocity, distance, and duration) in a multiparametric endpoints approach. Sub-lethal toxin levels in muscle tissue ranged from 0.006 to 0.077 µg g⁻¹ d.w. Results showed that fish exposed to toxic-dominated treatments showed significantly elevated EROD activity (up to 200 % increase), moderate increases in GR and GSTs, and reduced CAT activity compared to controls. Notably, distance travelled during escape responses was reduced by ∼50 % in the high-toxicity treatment and showed an inverse correlation with EROD activity, suggesting a trade-off between detoxification effort and swimming performance. Overall, our results demonstrate that EROD is a sensitive biomarker for cyanotoxin exposure in fish under natural bloom conditions. This finding highlights the need to consider natural cyanotoxin effects when interpreting environmental assessments, particularly given the projected increase in bloom frequency and severity under future climate scenarios.

由于富营养化和气候变化，蓝藻华在世界范围内加剧，增加了对水生生物的蓝藻毒素暴露。本研究研究了蓝藻华对三棘棘鱼（一种广泛分布的中游鱼类）的生理、生化和行为影响。将成年棘鱼暴露于自然收集的以有毒的spumigena Nodularia，无毒的aphanizomensp或50:50混合为主的开花材料中两周。我们用多参数端点方法测量了毒素积累（NODeq）、肝脏酶活性（乙氧基间苯二酚-o -去甲基化酶[EROD]、谷胱甘肽s -转移酶[GSTs]、谷胱甘肽还原酶[GR]和过氧化氢酶[CAT]）和逃逸游泳性能（质心速度、角速度、距离和持续时间）。肌肉组织中的亚致死毒素水平从0.006µg到0.077µg不等。结果显示，与对照组相比，暴露于毒素为主处理的鱼的EROD活性显著升高（高达200%），GR和GSTs适度增加，CAT活性降低。值得注意的是，在高毒性处理中，在逃逸反应期间行进的距离减少了约50%，并且与EROD活性呈负相关，这表明在解毒努力和游泳表现之间存在权衡。总的来说，我们的研究结果表明EROD是一个敏感的生物标志物，在自然水华条件下，鱼类暴露于蓝藻毒素。这一发现强调了在解释环境评估时考虑天然蓝藻毒素影响的必要性，特别是考虑到在未来气候情景下预计的藻华频率和严重程度的增加。

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引用次数: 0

More sustained, more severe blooms and shifting monthly patterns of the toxigenic dinoflagellate Karenia brevis on the West Florida Shelf 在西佛罗里达大陆架上，更持久，更严重的水华和每月变化的产毒甲藻短卡雷氏菌的模式

IF 4.5 1区生物学 Q1 MARINE & FRESHWATER BIOLOGY

Harmful Algae

Pub Date : 2025-09-02 DOI: 10.1016/j.hal.2025.102967

Patricia M. Glibert , Cynthia A. Heil , Ming Li

Various recent reports, based on different approaches, data sets and time periods, have yielded different conclusions with regard to whether blooms of the Florida red tide dinoflagellate, Karenia brevis, have increased over time. Without question, however, there have been a number of recent blooms that have been long lasting, continuing through the summer months normally taken to be outside the ideal temperature niche for K. brevis. Here, using a recently developed bloom severity index, the time series of blooms from 1970 to 2019 is examined, focusing on how monthly patterns have changed over time. More severe blooms have been found since the mid 1990s, now lasting 4- to 5-months longer than in previous decades, a trend related to the Oceanic Niño Index (El Niño -Southern Oscillation). Since the mid-1990s, water temperature anomalies have been related to bloom severity with lags of 3 to 6 months. The most significant temperature increases have occurred in the latter months of the year when K. brevis growth typically is highest. Increased flow from the Caloosahatchee River, and its total nitrogen load, are also predictors of recent bloom severity with lags of several months. Cells that survive the now-warmer winter dry season have adequate nutrients and may experience more favorable nitrogen forms as the summer wet season develops, and as nutrients are recycled, may “over summer”. The stresses of increased warming and increased nutrient pollution on K. brevis blooms will continue to make managing these blooms a challenge for management as climate change trajectories continue.

最近的各种报告，基于不同的方法、数据集和时间段，得出了关于佛罗里达赤潮鞭毛藻（短卡列尼亚）的繁殖是否随着时间的推移而增加的不同结论。然而，毫无疑问，最近出现了一些持续时间很长的花，持续了整个夏季，通常被认为是短链镰刀的理想温度环境之外。在这里，使用最近开发的水华严重指数，研究了1970年至2019年的水华时间序列，重点关注每月模式如何随着时间的推移而变化。自20世纪90年代中期以来，发现了更严重的水华，现在持续的时间比过去几十年长4到5个月，这一趋势与海洋Niño指数（El Niño -南方涛动）有关。自20世纪90年代中期以来，水温异常与水华严重程度有关，滞后时间为3至6个月。最显著的温度升高发生在一年中最后几个月，此时短链乳杆菌的生长通常是最高的。卡卢萨哈奇河的流量增加，以及它的总氮负荷，也预示着最近几个月的水华严重程度。在现在变暖的冬季旱季中存活下来的细胞有足够的营养，并且随着夏季雨季的发展和营养物质的循环，可能会经历更有利的氮形态，可能会“过夏”。随着气候变化轨迹的继续，变暖加剧和营养污染增加对短叶菊华的压力将继续使管理这些华成为一项挑战。

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引用次数: 0

Mesozooplankton grazing patterns and preferences during a cyanobacterial harmful algal bloom (cHAB) in a large eutrophic lake 大型富营养化湖泊蓝藻有害藻华（cHAB）期间中浮游动物的放牧模式和偏好

IF 4.5 1区生物学 Q1 MARINE & FRESHWATER BIOLOGY

Harmful Algae

Pub Date : 2025-08-29 DOI: 10.1016/j.hal.2025.102963

Daniel I. Peters , Lyndsie M. Collis , Morgan D. Shaw , Zak J. Slagle , Henry A. Vanderploeg , James M. Hood

Mesozooplankton (200–2,000 µm) are an important link between primary producers and higher-level consumers and can influence phytoplankton biomass and community structure via grazing. Yet, during cyanobacteria harmful algal blooms (cHABs) we have a poor understanding of which food resources mesozooplankton use and their grazing pressure on phytoplankton. To investigate this, we conducted two gradient-grazer assays to measure mesozooplankton community grazing rates in western Lake Erie during the 2021 cHAB season. We measured mesozooplankton grazing on various food sources, including: total phytoplankton, phytoplankton major taxa (Cyanobacteria, Cryptophyta/Bacillariophyta, Chlorophyta), and autotrophic and heterotrophic picoplankton and nanoplankton. We used these data to estimate mesozooplankton feeding selectivity, the importance of each food source toward mesozooplankton carbon intake, as well as the percent standing stock and growth consumed by mesozooplankton. Mesozooplankton selected for autotrophic and heterotrophic nanoplankton, were neutrally selective for Cryptophyta/Bacillariophyta, and avoided Cyanobacteria and the total phytoplankton community. Mesozooplankton carbon intake was dominated by autotrophic nanoplankton and Cyanobacteria, indicating these food sources may be important in supporting zooplankton production during these cHAB events, although our understanding of the incorporation of Cyanobacteria carbon into mesozooplankton production is limited. While mesozooplankton grazed a small portion of total phytoplankton (1–12 % d^-1) and Cyanobacteria (5–13 % d^-1) standing stock biomass (<200 µm), they exerted a relatively stronger control on the growth of total phytoplankton (4–38 % d^-1) and Cyanobacteria (64–106 % d^-1), primarily due to the low measured growth rates of these food items during the study. Our results demonstrate that mesozooplankton graze on Cyanobacteria during cHAB events, and under the right conditions influence cHAB dynamics through direct consumption of Cyanobacteria and indirect effects on Cyanobacteria grazers and competitors.

中浮游动物（200 - 2000µm）是初级生产者和高级消费者之间的重要纽带，可以通过放牧影响浮游植物的生物量和群落结构。然而，在蓝藻有害藻华（cHABs）期间，我们对浮游动物利用的食物资源及其对浮游植物的放牧压力知之甚少。为了研究这一点，我们在2021年cHAB季节对伊利湖西部的浮游动物群落进行了两次梯度放牧试验，测量了它们的放牧率。我们测量了以不同食物来源为食的中浮游动物，包括：总浮游植物、浮游植物主要分类群（蓝藻、隐藻/硅藻、绿藻）、自养和异养微浮游生物和纳米浮游生物。我们利用这些数据估计了浮游动物的取食选择性、每种食物来源对浮游动物碳摄入量的重要性，以及浮游动物的存量和生长消耗的百分比。中浮游动物对自养和异养纳米浮游生物有选择性，对隐藻/硅藻有中性选择性，对蓝藻和总浮游植物群落有选择性。中游浮游动物的碳摄入量主要由自养型纳米浮游生物和蓝藻控制，这表明这些食物来源可能在这些cHAB事件中支持浮游动物的生产中发挥重要作用，尽管我们对蓝藻碳在中游浮游动物生产中的作用的了解有限。虽然中浮游动物只占总浮游植物（1 - 12% d-1）和蓝藻（5 - 13% d-1）总生物量（200µm）的一小部分，但它们对总浮游植物（4 - 38% d-1）和蓝藻（64 - 106% d-1）的生长具有相对较强的控制作用，这主要是由于研究期间这些食物的测量生长率较低。研究结果表明，在cHAB事件中，中浮游动物以蓝藻为食，并在适当的条件下通过直接消耗蓝藻和间接影响蓝藻捕食者和竞争对手来影响cHAB动态。

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引用次数: 0

Critical flow velocity thresholds for preventing persistent thermal stratification and cyanobacterial blooms in rivers 防止河流中持续热分层和蓝藻华的临界流速阈值

IF 4.5 1区生物学 Q1 MARINE & FRESHWATER BIOLOGY

Harmful Algae

Pub Date : 2025-08-26 DOI: 10.1016/j.hal.2025.102962

D.C. Davis , J.A. Facey , A.J. Brooks , D.P. Westhorpe , M. Balzer , N. Williamson , S.M. Mitrovic

Toxic cyanobacterial harmful algal blooms (cHABs) are a major worldwide issue in freshwater environments, exacerbated by climate change with rising water temperatures and prolonged and intensified periods of thermal stratification. The Barwon-Darling River in Australia, a dryland river with a highly variable flow regime, often experiences persistent thermal stratification (PTS), i.e., continuous stratification for days or weeks, during periods of low discharge, commonly resulting in cHABs. This study evaluated whether a critical flow velocity threshold can prevent or disrupt the formation of PTS and subsequent cHABs. The relationships between gauged discharge and flow velocity were determined within six weir pools along the river using acoustic Doppler current profiling. These relationships were used to interpret 20 years of historic daily river discharge data as mean cross-sectional flow velocities which were then compared to cyanobacterial biovolumes over the same period, focusing predominantly on the potentially toxic genera Dolichospermum. An upper limiting relationship between flow velocity and Dolichospermum biovolume was found and almost all blooms > 4 mm³/L (exceeding the Australian recreational safety guidelines for toxic cyanobacteria) occurred when maximum antecedent 7-day flow velocities were less than 0.05 m/s. Quantile regression estimates suggested maintaining flow velocities of 0.05 m/s can limit blooms to 3.96 mm³/L while increasing flow velocities will reduce this limit. These findings support the premise of using river flow velocity thresholds for cHAB management when blooms are related to PTS. These flow velocities should be applicable to other rivers in similar climates while the approach could be utilised more widely.

有毒蓝藻有害藻华（cHABs）是淡水环境中的一个主要全球性问题，随着水温上升和热分层期的延长和加剧，气候变化加剧了这一问题。澳大利亚的巴温-达令河是一条流量变化很大的旱地河流，在低流量期间，经常经历持续的热分层（PTS），即连续分层数天或数周，通常导致chab。本研究评估了临界流速阈值是否可以阻止或破坏PTS和随后的chab的形成。利用声学多普勒电流谱法测定了沿江6个堰池的流量与流速之间的关系。这些关系被用来解释20年的历史每日河流流量数据作为平均横断面流速，然后将其与同期的蓝藻生物量进行比较，主要关注潜在有毒的Dolichospermum属。水流速度与Dolichospermum生物体积之间存在上限关系，几乎所有的水华>； 4 mm3/L（超过澳大利亚有毒蓝藻娱乐安全指南）都发生在之前最大7天水流速度小于0.05 m/s时。分位数回归估计表明，保持0.05 m/s的流速可以将华花限制在3.96 mm3/L，而增加流速会降低这一限制。这些发现支持了在华花与PTS相关时使用河流流速阈值进行cHAB管理的前提。这些流速应该适用于类似气候条件下的其他河流，而这种方法可以得到更广泛的应用。

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引用次数: 0

Faunal associations of holopelagic Sargassum spp. in the subtropical and tropical northern Atlantic: A review 亚热带和热带北大西洋全浮游马尾藻的区系关联研究进展

IF 4.5 1区生物学 Q1 MARINE & FRESHWATER BIOLOGY

Harmful Algae

Pub Date : 2025-08-25 DOI: 10.1016/j.hal.2025.102961

L.Verónica Monroy-Velázquez , Hazel M. Canizales-Flores , Karla A. Camacho-Cruz , Makeda Corbin , Patricia Briones-Fourzán , Brigitta I. van Tussenbroek

Holopelagic Sargassum spp. (Sargassum from hereon) are the founding seaweeds of biodiverse high-sea rafts. The floating rafts provide substrate, shelter, feeding-, and breeding grounds for numerous marine species, making them unique communities in the high seas. Similar to other pelagic systems, the community associated with the rafts is dynamic, inherently variable, and defined by the dynamics of the rafts and interactions between the seaweed and associated fauna. The high biodiversity, including organisms from different trophic levels, results in multiple interactions and complex food webs, which are covered in this review. Additionally, we highlight how floating Sargassum acts as a vector of ecological connectivity, influencing distant ecosystems such as coastal and deep-sea habitats. These cross-ecosystem interactions occur through organism transport, organic matter export and trophic linkages. Understanding these connections is key to recognizing the broader ecological role of Sargassum rafts and the multiple ecosystem services they provide.

全海马尾藻属（此处为马尾藻）是生物多样性高海筏的基础海藻。浮筏为许多海洋物种提供了基质、庇护所、觅食和繁殖地，使它们成为公海上独特的群落。与其他远洋系统类似，与木筏相关的群落是动态的，内在可变的，并由木筏的动态以及海藻和相关动物群之间的相互作用来定义。生物多样性高，包括来自不同营养水平的生物，导致多种相互作用和复杂的食物网，这是本文的综述。此外，我们强调了漂浮马尾藻如何作为生态连通性的载体，影响遥远的生态系统，如沿海和深海栖息地。这些跨生态系统的相互作用通过生物运输、有机物输出和营养联系发生。了解这些联系是认识马尾藻筏更广泛的生态作用及其提供的多种生态系统服务的关键。

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引用次数: 0

Salinity adaption and toxicity of harmful algal blooms in three bays of Great Salt Lake (USA) 美国大盐湖三个海湾有害藻华的盐度适应及毒性研究

IF 4.5 1区生物学 Q1 MARINE & FRESHWATER BIOLOGY

Harmful Algae

Pub Date : 2025-08-25 DOI: 10.1016/j.hal.2025.102959

W.A. Wurtsbaugh , Malin Olofsson , Gregory L. Boyer , Amy M. Marcarelli

Cyanobacterial blooms can be harmful to animals and humans exposed to their toxins; however, their environmental drivers and boundaries still need to be elucidated. Salinity has been demonstrated to be an important driver of community composition that sets boundaries of species migration and survival. The filamentous cyanobacteria Nodularia spumigena forms dense blooms in estuaries around the world, produces the hepatotoxin nodularin, and has been thought to not survive or fix nitrogen (N) in high salinities. From 2005–2009 we studied three bays of Great Salt Lake (USA), two of which are estuaries with salinities ranging from 0 to >90 g l^-1 while the third, Gilbert Bay, had a salinity near 160 g l^-1. Bear River Bay and the larger Gilbert Bay were meso‑eutrophic, while Farmington Bay, which receives direct inputs of secondary-treated sewage, was hypereutrophic with mean chlorophyll concentrations of 149 µg l^-1 and dense blooms of N. spumigena. Cell densities were >500 times those of Nodularia studied in the Baltic Sea. In Farmington Bay blooms occur at salinities ranging from 8–50 g l^-1, which are much higher than usually reported for this taxon. Concentrations of the cyanotoxin nodularin reached 660 µg l^-1 (mean = 41 µg l^-1), far above critical thresholds for contact recreation and above those causing bird mortalities elsewhere. The mean N₂ fixation rate of Nodularia measured over a salinity range of 14 to 52 g l^-1 was 47 mg N m^-2 d^-1, which is among the highest reported values for freshwater and marine ecosystems. The local adaptation of Nodularia to the extreme salinity conditions in Great Salt Lake furthers our understanding of salinity adaptation and the potential spread of this species to new regions.

蓝藻的大量繁殖可能对接触其毒素的动物和人类有害；然而，它们的环境驱动因素和边界仍然需要阐明。盐度已被证明是群落组成的重要驱动因素，它设定了物种迁移和生存的界限。丝状藻蓝藻结核菌在世界各地的河口形成密集的水华，产生肝毒素结核素，并且被认为不能在高盐度中生存或固定氮(N)。2005-2009年，我们研究了美国大盐湖的三个海湾，其中两个是盐度在0到90 g -1之间的河口，而第三个吉尔伯特湾的盐度接近160 g -1。熊河湾和较大的吉尔伯特湾为中富营养化，而法明顿湾则为富营养化，平均叶绿素浓度为149µg l-1，藻华密集。细胞密度是波罗的海结核菌的500倍。在法明顿湾，水华发生在8 - 50g -1的盐度范围内，这比通常报道的这个分类单元要高得多。蓝藻毒素结核素的浓度达到660µg -1（平均值为41µg -1），远远高于接触娱乐的临界阈值，也高于其他地方导致鸟类死亡的阈值。在14 ~ 52 g -1的盐度范围内，结核菌的平均固氮率为47 mg N - m-2 - d-1，是淡水和海洋生态系统中报告的最高值之一。大盐湖极端盐度条件下结节藻的局部适应进一步加深了我们对盐度适应和该物种向新地区传播的潜在认识。

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引用次数: 0