Harmful Algae最新文献

{"title":"Spatiotemporal distribution, composition, and influencing factors of lipophilic marine algal toxins in the Beibu Gulf, China: Implications for necessity of offshore seawater monitoring","authors":"Wee Vian Low ,&nbsp;Li Zhang ,&nbsp;Pengbin Wang ,&nbsp;Pengfei Zheng ,&nbsp;Xi Yang ,&nbsp;Lu Lu ,&nbsp;Junjie Zheng ,&nbsp;Zuhao Zhu ,&nbsp;Jie Chen ,&nbsp;Mengmeng Tong","doi":"10.1016/j.hal.2025.102845","DOIUrl":"10.1016/j.hal.2025.102845","url":null,"abstract":"<div><div>Lipophilic marine algal toxins (LMATs) are persistent, bioaccumulative metabolites that pose significant threats to marine biodiversity and seafood safety. To comprehensively understand LMATs pollution in offshore natural fishing grounds, we investigated the spatiotemporal distribution and composition of 13 LMATs in surface seawater in Beibu Gulf's offshore area, along with their key influencing factors and latitudinal variations across coastal regions in China. We detected 20-methyl spirolide G (SPX20G) for the first time in coastal waters in China, alongside other frequently detected LMATs, including okadaic acid (OA), dinophysistoxin-1 (DTX1), pectenotoxin-2 (PTX2), azaspiracid-1 (AZA1), azaspiracid-2 (AZA2), gymnodimine (GYM), and 13-desmethyl spirolide C (SPX1). Significant seasonal variations were observed, with summer exhibiting eight LMAT types and higher total LMAT concentrations (ΣLMATs) (16.92 ± 20.45 ng/L) compared to winter's five LMAT types and ΣLMATs concentrations at 5.63 ± 3.30 ng/L. Predominant PTX2 and OA concentrations showed a decreasing trend from northern to southern Beibu Gulf, while other LMATs were distributed in patches, particularly in summer. Notably, cyclic imines (GYM and SPX1) were detected with high frequencies and concentrations, underscoring the need for their monitoring. Spearman correlation and redundancy analyses identified water depth, chlorophyll <em>a</em> (Chl<em>a</em>), temperature, salinity, nutrients (DIN:DIP and SiO₃²⁻), and dissolved oxygen (DO) as key factors influencing LMATs distribution in the Beibu Gulf. Latitudinal analysis of LMAT contents across Chinese waters revealed DTX1 as more prevalent at higher latitudes, and GYM, SPX1, and AZA1 more common at lower latitudes, while ΣLMATs concentrations from this study ranked at moderate to high levels compared to other regions. Therefore, special attention is required for LMATs pollution in offshore fishing areas.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"145 ","pages":"Article 102845"},"PeriodicalIF":5.5,"publicationDate":"2025-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143767508","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Multi-year dynamics of harmful algae in Disko Bay, West Greenland","authors":"Cora Hoerstmann ,&nbsp;Per Juel Hansen ,&nbsp;Nina Lundholm ,&nbsp;Bernd Krock ,&nbsp;Uwe John","doi":"10.1016/j.hal.2025.102857","DOIUrl":"10.1016/j.hal.2025.102857","url":null,"abstract":"<div><div>Harmful algal blooms (HABs) increasingly affect Arctic coastal ecosystems, due to hydrographic and bathymetric conditions that support the accumulation of cells and cysts, and coupled with increasing temperatures, extensive bloom events can be easily triggered. However, various harmful algae species have been reported in the past and it is unclear which are most threatening in Greenlandic waters, a region that vitally depend on its fisheries. Here, we explore the diversity and succession of harmful algae by metabarcoding at a multi-year station in Greenlandic coastal waters, offering a comprehensive analysis of species dynamics over time. Dinoflagellates, diatoms and haptophytes, known for their toxin production and potential negative effects on ecosystems and food webs, were regularly detected across years and throughout all sampled months. Yet, results also indicate significant interannual variability in harmful algal occurrences, with high abundances of <em>Alexandrium</em> and increasing abundances of <em>Aureococcus, Prymnesium</em>, and <em>Pseudo-nitzschia.</em> Through a boosted regression tree analysis of the ecological drivers of HABs in Arctic waters, we identified an important role of climate-induced environmental variables such as temperature, salinity, and the number of ice-free days year^-1. These findings provide critical baseline data for understanding the future risks of HABs in the Arctic and underscore the importance of ongoing, high-resolution monitoring.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"145 ","pages":"Article 102857"},"PeriodicalIF":5.5,"publicationDate":"2025-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143816445","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Does Microcystis exposure history facilitate adaptation of Diaphanosoma dubium to expanding filamentous cyanobacterium Raphidiopsis raciborskii?","authors":"Qiuqi Lin,&nbsp;Xiao Xiao,&nbsp;Xuxin Feng,&nbsp;Lamei Lei","doi":"10.1016/j.hal.2025.102847","DOIUrl":"10.1016/j.hal.2025.102847","url":null,"abstract":"<div><div><em>Diaphanosoma</em>, so-called ‘tropical <em>Daphnia</em>’ are widely distributed in warm waterbodies with <em>Microcystis</em> blooms, and are supposed to have high level of tolerance to <em>Microcystis</em>. However, expanding filamentous cyanobacterium, <em>Raphidiopsis raciborskii</em> is increasingly replacing <em>Microcystis</em>, or becoming co-dominant in warm eutrophic waterbodies. Whether previous experience with <em>Microcystis</em> can facilitate adaptation of <em>Diaphanosoma</em> to <em>R. raciborskii</em> or a shift in cyanobacteria assemblage from <em>Microcystis</em> to <em>R. raciborskii</em> will reduce their tolerance to cyanobacteria is debated. We address this question by investigating the performance of fourteen clones from three <em>Diaphanosoma dubium</em> populations differing in cyanobacteria exposure history. They were fed pure diets of cylindrospermopsin-/non-cylindrospermopsin-producing <em>R. raciborskii</em>, microcystin-producing <em>Microcystis aeruginosa</em> and green alga <em>Auxenochlorella pyrenoidosa</em>. The three cyanobacteria all sustained the growth and reproduction of three <em>D. dubium</em> populations, and both somatic and population growth rates increased with dietary PUFA content for each clone, irrespective of manageability and toxicity. Clones with cyanobacteria exposure history have much better performance than those without exposure history on all food types. Moreover, clones with <em>Microcystis</em> exposure history for &gt;40 years, performed better on all food types than clones with <em>R. raciborskii</em> exposure history for &lt;10 years. The results suggest that <em>D. dubium</em> population with much longer bloom exposure history may adapt to being more tolerant of toxic cyanobacteria in the diet. We infer that previous <em>Microcystis</em> exposure experience might facilitate adaptation of <em>D. dubium</em> to <em>R. raciborskii</em> by enhancing their ability to cope with nutritional constraint and toxicity.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"145 ","pages":"Article 102847"},"PeriodicalIF":5.5,"publicationDate":"2025-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143759674","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"From bloom to tap: Connecting harmful algal bloom indicators in source water to cyanotoxin presence in treated drinking water","authors":"Lena Abu-Ali,&nbsp;Ryan J. Albert,&nbsp;Angela B. Davis,&nbsp;Rachel Gonsenhauser,&nbsp;Katherine Foreman","doi":"10.1016/j.hal.2025.102846","DOIUrl":"10.1016/j.hal.2025.102846","url":null,"abstract":"<div><div>Cyanotoxins produced by harmful algal blooms (HABs) can negatively impact human health through ingestion of drinking water. Under most circumstances, public water systems (PWSs) have demonstrated that they can successfully manage the removal of low-to-moderate levels of cyanotoxins with conventional treatment. Intense or frequent blooms put some PWSs at higher risk for treatment breakthrough, meaning cyanotoxins can pass through the drinking water treatment process, and there are still some instances of reported cyanotoxin levels in drinking water. This study links cyanotoxin drinking water occurrence data from PWSs sampled under the Fourth Unregulated Contaminant Monitoring Rule (UCMR 4) with qualitative source water HAB information to understand the relationship between source water indicators and drinking water occurrence. During the monitoring period (2018 to 2020), 153 of approximately 110,000 total cyanotoxin analytical results from 67 PWSs were observed at or above the minimum reporting level (MRL), resulting in a 0.14 percent rate of occurrence in drinking water. The associated qualitative data indicated that 23.9 percent of systems with a cyanotoxin reported value ≥ MRL in drinking water also reported the presence of a HAB indicator while 1.7 percent of systems with a reported value ≥ MRL in finished water did not report any HAB indicators. Odds ratio testing revealed that a system is more than twice as likely to have a cyanotoxin detection in drinking water if a HAB indicator is observed. This study demonstrates the importance of monitoring source water changes and observed treatment changes for vulnerable systems, as these can facilitate timely adjustments to treatment and mitigate the risks of cyanotoxin breakthrough in finished water.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"145 ","pages":"Article 102846"},"PeriodicalIF":5.5,"publicationDate":"2025-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143816485","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Extracellular polymeric substances enhanced photosynthesis over respiration in Microcystis aeruginosa","authors":"Kaikai Deng ,&nbsp;Rui Yang ,&nbsp;Shirong Zhang ,&nbsp;Fang Fang ,&nbsp;Yuanchen Huo ,&nbsp;Peng Yan ,&nbsp;Youpeng Chen ,&nbsp;Jinsong Guo","doi":"10.1016/j.hal.2025.102843","DOIUrl":"10.1016/j.hal.2025.102843","url":null,"abstract":"<div><div>Extracellular polymeric substances (EPS) play a critical role in <em>Microcystis</em>-dominated freshwater cyanobacterial blooms. However, the mechanisms through which EPS affects <em>Microcystis</em> photosynthesis, respiration, and further affects its growth are not understood completely. To address this, we investigated the effects of varying EPS concentrations on the physiological processes of <em>Microcystis aeruginosa</em>. The results demonstrated that increasing EPS concentrations significantly enhanced both cell density and energy fixation efficiency, accompanied by a reduction in CO₂ emission flux. Specifically, compared with the control group, the addition of 20 mg·L^-¹ EPS increased respiratory rates by 2.14 μmol·mg·h^-¹ and photosynthetic rates by 2.48 μmol·mg·h^-¹, suggesting that EPS stimulated both respiration and photosynthesis, with a more pronounced effect on photosynthesis, thereby leading to a substantial increase in algal growth. Further analysis indicated that EPS enhanced respiration by retaining hydrolases capable of breaking down macromolecules into bioavailable micromolecular substrates, which elevated acetyl-CoA concentrations and citrate synthase activity, thus improving respiratory efficiency. In terms of photosynthesis, EPS enhanced light utilization, as indicated by an increase in F_V/F_M, and improved the efficiency of inorganic carbon supply by enriching CO₂ and creating extracellular inorganic carbon gradients. Moreover, EPS enhanced the activities of carbonic anhydrase and ribulose bisphosphate carboxylase/oxygenase. These findings emphasize the essential role of EPS in promoting algal growth and its potential impact on CO₂ fixation. Future research should incorporate the role of EPS in reducing carbon limitation into discussions of algal growth mechanisms and develop technologies that use algal blooms to harvest high-value carbon products such as ethanol, astaxanthin, lipids, and other valuable compounds.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"145 ","pages":"Article 102843"},"PeriodicalIF":5.5,"publicationDate":"2025-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143725852","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mixotrophic flagellate Ochromonas gloeopara promotes heterocyst production in cyanobacteria with altered filament length","authors":"Wenting Zhong ,&nbsp;Yulin Wang ,&nbsp;Yao Wang ,&nbsp;Junjun Wei ,&nbsp;Yuan Huang ,&nbsp;Zhou Yang","doi":"10.1016/j.hal.2025.102844","DOIUrl":"10.1016/j.hal.2025.102844","url":null,"abstract":"<div><div>Heterocystous cyanobacteria can adapt to environmental fluctuations typically via the production of heterocyst, a specialized cell functioning dinitrogen-fixing. Responses of heterocyst production to abiotic stressors like nutrient availability have been widely studied. In natural environments cyanobacteria also face great pressures from a variety of organisms including mixotrophic protists<em>.</em> However, little is known about the impacts of mixotrophic protists on the filamentous cyanobacteria characterized by heterocyst production. Here, we explored the grazing of the flagellate <em>Ochromonas gloeopara</em> on two heterocystous cyanobacteria <em>Dolichospermum flos-aquae</em> and <em>Anabaena</em> sp., together with the cyanobacterial responses in terms of population growth, heterocyst production, filament length and photosynthesis. Results showed that <em>O. gloeopara</em> preyed on short filaments of both cyanobacteria, reducing the population growth rate of <em>D. flos-aquae</em> but not the <em>Anabaena</em> sp. The average filament length of the two species was generally increased by <em>O. gloeopara</em> grazing at the initial cultivation, whereas reversed phenomenon was observed in <em>Anabaena</em> sp. at late cultivation. <em>O. gloeopara</em> presence promoted the heterocyst production in both the cyanobacteria, with heterocyst abundance showing a rapid increase followed by decrease dynamic with cultivation. Heterocyst placement pattern was also changed with the number of vegetative cells between heterocysts increased in <em>Anabaena</em> sp. At the peak phase of heterocyst production, the maximum quantum efficiency of photosynthesis in <em>D. flos-aquae</em> enhanced as response to <em>O. gloeopara</em> presence. These findings reveal a phenotypic adaptation of heterocystous cyanobacteria to pressures from mixotrophic protists, providing a new perspective for understanding the role of biotic interactions in cyanobacterial blooms.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"145 ","pages":"Article 102844"},"PeriodicalIF":5.5,"publicationDate":"2025-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143725851","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Phosphorus rather than nitrogen driving biosynthesis of diarrhetic shellfish toxins in Prorocentrum caipirignum via ATP","authors":"Heng Chen ,&nbsp;Zehui Huang ,&nbsp;Wanchun Guan ,&nbsp;Kaixuan Huang ,&nbsp;Lei Cui ,&nbsp;Hua Zhang ,&nbsp;Songhui Lu","doi":"10.1016/j.hal.2025.102842","DOIUrl":"10.1016/j.hal.2025.102842","url":null,"abstract":"<div><div>Okadaic acid and its analogues such as dinophysisitoxins-1, -2 (DTX-1, -2) are potent inhibitors of protein phosphatase and causative toxins of diarrhetic shellfish poisoning (DSP). These toxins are produced by dinoflagellate genera <em>Dinophysis</em> and <em>Prorocentrum</em>. Numerous studies have reported that the cellular content of these toxins increased under macronutrient limitation or other stress conditions in genus <em>Prorocentrum</em>. However, our recent study demonstrated positive linear or exponential relationships between toxin production rate (<em>R</em>_tox) and phosphate consumption rate in five strains of <em>P. lima</em> complex/<em>P. caipirignum</em>. To further clarify macronutrients roles in OA production, <em>P. caipirignum</em> SE10 selected for its extremely low DTX-1 content due to potential competitive relationship with OA, was exposed to nitrogen (N) or phosphorus (P) limitation via batch or semi-batch cultures, after which the depleted nutrients were replenished to assess OA production dynamics. The <em>R</em>_tox of OA peaked initially before declining under both N and P-limited treatments. Notably, <em>R</em>_tox increased only upon P replenishment rather than N replenishment, confirming phosphorus's critical role in OA production. In P-addition experiments, <em>R</em>_tox stagnated in the P-deficient condition but rose proportionally with increasing P concentration. Meanwhile, ATP and NADPH levels surged 7.5-fold and 1.5-fold, respectively, within 1 h of P-addition compared to P-deficient treatment. To probe how P affects OA production, inhibitors targeting ATP and NADPH synthesis were applied. OA production was specifically suppressed by ATP inhibitors, such as N, N-dicyclohexylcarbodiimid (DCCD), rotenone (ROT), and 2,4-dintrophenol (DNP). The highest inhibition occurred with 20 μM DCCD, reducing OA cellular content by 90 % after 48 h. Moreover, increasing ATP inhibitor concentration shift <em>R</em>_tox from positive to negative values. These finding demonstrated that phosphorus drives OA production primarily by modulating ATP levels, which directly regulate toxin synthesis.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"145 ","pages":"Article 102842"},"PeriodicalIF":5.5,"publicationDate":"2025-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143767509","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"World's largest oligotrophic Lake Baikal: Concerns about cyanobacterial blooms and potential microcystin producers along the littoral zone","authors":"Xi Li ,&nbsp;Irina V. Tikhonova ,&nbsp;Sergey A. Potapov ,&nbsp;Andrey Yu. Krasnopeev ,&nbsp;Natalya A. Zhuchenko ,&nbsp;Xin Niao ,&nbsp;Lin Wang ,&nbsp;Ekaterina G. Sorokovikova ,&nbsp;Weixuan Wang ,&nbsp;Olga I. Belykh","doi":"10.1016/j.hal.2025.102841","DOIUrl":"10.1016/j.hal.2025.102841","url":null,"abstract":"<div><div>Toxic cyanobacterial blooms are great challenge for water safety globally. Previous studies mainly focused on this issue in eutrophic lakes, but associated knowledge in oligotrophic lakes is quite scarce. Lake Baikal is the world's largest oligotrophic lake, containing about 20 % of world's available freshwater. In this study, sites grouped in the east (E1-E2), west (W1-W6), and southwest (SW1-SW3) located in the littoral zone of Lake Baikal, were sampled. The target genes of <em>16S rRNA</em> and <em>mcyE</em> in cyanobacteria, potential microcystin producers, microcystin-producing <em>Microcystis</em> and <em>Dolichospermum</em>, were quantitatively detected in collected surface water samples, and the highest target gene abundance was observed at the site where the highest water temperature (WT) and total nitrogen (TN) were recorded <em>(P</em> <em>&lt;</em> <em>0.05).</em> The WT showed a strong positive correlation with the target gene abundance, possibly via promoting the growth of cyanobacteria, potential microcystin producers or toxic strain proportion. The strong positive correlation between TN and absolute <em>mcyE</em> gene abundance of potential microcystin producers was also shown, and it was likely that its production is related to N availability. These findings suggested that the potential risk of cyanobacterial blooms and microcystin producers for water safety should not be ignored in the world's largest oligotrophic Lake Baikal, and WT and TN could be as pivotal factors to affect the potential risk. Consequently, it is vitally necessary for water authorities to take suitable action to cope with this challenge in hot spot littoral region of increased water temperature and nitrogen in a large oligotrophic lake.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"144 ","pages":"Article 102841"},"PeriodicalIF":5.5,"publicationDate":"2025-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143698103","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Monitoring pelagic Sargassum in the Atlantic Ocean from space: Principles and practices","authors":"Chuanmin Hu ,&nbsp;Brian B. Barnes ,&nbsp;Lin Qi ,&nbsp;James F.R. Gower ,&nbsp;Junnan Jiao ,&nbsp;Yuyuan Xie","doi":"10.1016/j.hal.2025.102840","DOIUrl":"10.1016/j.hal.2025.102840","url":null,"abstract":"<div><div>While pelagic <em>Sargassum</em> as a critical habitat to marine animals is known to be abundant in the Sargasso Sea, Gulf of Mexico, and the Caribbean Sea, attempts to detect this brown macroalgae from space did not start until 2006 when the proof of concept was demonstrated with medium-resolution satellite sensors. The annually recurrent Great Atlantic <em>Sargassum</em> Belt (GASB) since 2011 motivated efforts to develop new algorithms and approaches to detect and quantify <em>Sargassum</em> using data collected by various satellite sensors. This is mainly because of this macroalgae's harmful impacts on the coastal environments. Here, we review the principles and practices of using satellite remote sensing to map, quantify, and monitor pelagic <em>Sargassum</em> in the Atlantic Ocean. We first present the concept of how <em>Sargassum</em> can be detected, discriminated (against look-alikes), and quantified, where four types of data products are defined to meet the various needs. Then, we present the various published approaches in realizing such a concept using data collected by different satellite sensors. Following this concept and using recently developed algorithms and medium-resolution satellite data, we show the spatial distribution patterns and temporal changes of the GASB as well as a near real-time system to monitor <em>Sargassum</em> in the GASB. Finally, we discuss the gaps in the current technology and propose pathways forward to fill these gaps.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"144 ","pages":"Article 102840"},"PeriodicalIF":5.5,"publicationDate":"2025-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143715711","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Environmental-level antibiotics disrupt Microcystis stoichiometry: An overlooked risk in the context of cyanobacterial harmful algal blooms","authors":"Ganyu Feng ,&nbsp;Zhipeng Duan ,&nbsp;Liang Wu ,&nbsp;Yunze Gao ,&nbsp;Yuan Zhang ,&nbsp;Fang Li ,&nbsp;Xiang-Zhou Meng","doi":"10.1016/j.hal.2025.102839","DOIUrl":"10.1016/j.hal.2025.102839","url":null,"abstract":"<div><div>At trace levels (nanograms to micrograms per liter, ng L^-1 – μg L^-1), antibiotics exert stimulatory effects on cyanobacteria, potentially posing a threat to aquatic ecosystems. Here, environmentally relevant concentrations of antibiotics were firstly observed to disrupt the stoichiometry of cyanobacterium <em>Microcystis</em> (<em>i.e.</em>, the quota and allocation patterns of carbon (C), nitrogen (N), and phosphorus (P)). In scenarios where the doses of antibiotics ranged from 50 to 200 ng L^-1, cyanobacteria displayed a complex response – a reduction of their intracellular P pools by 22% to 24% and an adjustment of elemental allocation patterns, such as by a 51% increase in the ratio of C:P. Furthermore, at these doses, antibiotics significantly impacted the physiology of cyanobacteria, resulting in increased production of extracellular polymeric substances (EPS), a substantial rise in maximum biomass (169% to 219% increase), and an enlargement of colony size (22% to 37% increase). Transcriptomic analyses revealed that these changes were linked to the downregulation of ABC transporters and the upregulation of photosynthetic and ribosomal processes. This research offers novel insights into the hormesis effects on cyanobacteria and bloom formation, highlighting the necessity of using a multidimensional evaluation framework that integrates comprehensive bloom factors (biomass, colony size, and EPS) and elemental profiles (C, N, and P quotas and ratios) for accurate assessment.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"144 ","pages":"Article 102839"},"PeriodicalIF":5.5,"publicationDate":"2025-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143637710","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}