Harmful Algae最新文献

{"title":"A novel hybrid cyanobacteria mapping approach for inland reservoirs using Sentinel-3 imagery","authors":"Thainara M.A. de Lima ,&nbsp;Claudio C.F. Barbosa ,&nbsp;Cristina S.F. Nordi ,&nbsp;Felipe N. Begliomini ,&nbsp;Vitor S. Martins ,&nbsp;Fernanda S.Y. Watanabe ,&nbsp;Raianny L.N. Wanderley ,&nbsp;Rejane S. Paulino","doi":"10.1016/j.hal.2025.102836","DOIUrl":"10.1016/j.hal.2025.102836","url":null,"abstract":"<div><div>Detecting and quantifying cyanobacteria algal bloom occurrence plays an important role in preventing public health risks and understanding aquatic ecosystem dynamics. Satellite remote sensing has been used as an important data source to estimate cyanobacteria biomass based on pigment concentration. Phycocyanin (PC) is a unique pigment of inland water cyanobacteria and has been widely used as a proxy for cyanobacteria algal biomass. Based on the PC absorption feature around 620 nm, scientific efforts have been made to develop bio-optical models for orbital satellite observations, but proposed PC models limit the retrievals at different concentration ranges and depend on empirical models calibrated for specific aquatic environments. This study proposes a hybrid machine learning approach for PC retrieval that efficiently adopts the optimal algorithm for specific PC concentration ranges. An <em>in-situ</em> dataset of 165 samples was collected between November 2020 and December 2021 to support full training and validation of the proposed method. First, a Random Forest algorithm was applied to classify PC-low-concentration waters (0 – ∼14 mg.m⁻³) and PC-high-concentration waters (∼14.1 – 300 mg.m⁻³). Then, for each defined class, an individual PC estimation algorithm was calibrated. The final PC-hybrid model was applied to atmospherically corrected Sentinel-3/OLCI imagery derived by three approaches (L2-WFR, 6SV, and ACOLITE). The PC hybrid-model performance was evaluated by comparing the estimated PC concentration from satellite and in situ measurements. The hybrid PC model estimates (median symmetric accuracy (ζ) = 25.35%) outperformed the individual PC algorithms calibrated for the entire range of PC concentration, proving the practical applicability for quantifying PC concentration in optically dynamic waters.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"144 ","pages":"Article 102836"},"PeriodicalIF":5.5,"publicationDate":"2025-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143562059","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comparative genomic and phylogenetic analysis of mitochondrial genomes of the Pseudo-nitzschia HAB species","authors":"Ziyan He ,&nbsp;Hui Wang ,&nbsp;Yang Chen ,&nbsp;Nansheng Chen","doi":"10.1016/j.hal.2025.102829","DOIUrl":"10.1016/j.hal.2025.102829","url":null,"abstract":"<div><div>The genus <em>Pseudo-nitzschia</em> within Bacillariophyta (diatoms) is best known for its rich collection of toxigenic harmful algal bloom (HAB) species capable of producing the neurotoxin domoic acid (DA), which causes amnesic shellfish poisoning (ASP) in humans. Molecular markers such as 18S rDNA, ITS1, and ITS2 have been applied to facilitate <em>Pseudo-nitzschia</em> species identification because morphology-based methods often could not adequately distinguish different species due to their morphological similarities and plasticity. In this study, we constructed mitochondrial genomes (mtDNAs) for 11 <em>Pseudo-nitzschia</em> species and assessed their utility as “super-barcodes” for species identification and evolutionary analysis. These mtDNAs exhibited conserved genome structures despite variability in repeat regions. A potential <em>tatA-tatC</em> gene fusion event was observed in a single <em>Pseudo-nitzschia</em> species <em>P. brasiliana</em>. We also observed intron variability in <em>cox1</em> genes. Phylogenetic analyses of mtDNAs, chloroplast genomes (cpDNAs), and nuclear ribosomal DNA (nrDNA) arrays revealed consistent results, supporting the closely related but distinct clustering of the genera <em>Fragilariopsis</em> and <em>Pseudo-nitzschia</em>. We further designed a high-resolution molecular marker <em>tatA</em> for species identification based on the comparative analysis of these mtDNAs, which could be used to track <em>Pseudo-nitzschia</em> diversity. These findings offer new genome resources and new insights into the genetic evolution and classification of <em>Pseudo-nitzschia</em>, underscoring the need for continued research in this field.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"144 ","pages":"Article 102829"},"PeriodicalIF":5.5,"publicationDate":"2025-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143512228","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":"Responses of mussel farms to harmful algal bloom governance are shaped by the scale of production: Implications for equitable blue economy","authors":"Vicente I. Villalobos ,&nbsp;Diego F. Morales-Torres ,&nbsp;Nelson Valdivia ,&nbsp;María I. Rivera-Hechem ,&nbsp;Ricardo Giesecke ,&nbsp;Andrea Piñones ,&nbsp;Jorge I. Mardones ,&nbsp;José Garcés-Vargas ,&nbsp;Cristian J. Segura ,&nbsp;Jorge M. Navarro ,&nbsp;Luis Outeiro","doi":"10.1016/j.hal.2025.102821","DOIUrl":"10.1016/j.hal.2025.102821","url":null,"abstract":"<div><div>Small-scale aquaculture is essential to balance environmental health, economic growth, and social equity. However, the increasing frequency of Harmful Algae Blooms (HABs), commonly known as red tides, present a significant risk to both aquatic ecosystems and human well-being, threatening the productivity of the sector. This study investigates the impact of HAB-induced closures on mussel farming in Chile, the world's second-largest mussel industry, with a focus on how farm size influences resilience and adaptive capacity. With a 19-year dataset (2003–2021) covering small (&lt;3 ha), medium (3–8 ha), and large (&gt;8 ha) mussel farms, we analysed the temporal and spatial distribution of HAB closures and their effects on mussel export volumes. Using Generalized Additive Mixed Models (GAMMs), we reveal that small farms, while attempting rapid post-closure recovery, are more vulnerable to prolonged economic stress, primarily due to limited access to adaptive resources and fluctuating market prices. Larger farms, on the other hand, demonstrate a delayed but stable recovery, benefiting from superior spatial positioning and access to capital. While the industry showed sustained growth at the regional level, our analysis demonstrated an asymmetric, size-dependent pattern on local responses, where small producers are more vulnerable to unexpected climatic events and market fluctuations. Given the increasing frequency of HABs due to climate change, our findings underscore the need for equitable governance in the blue economy to prevent widening inequalities between small and large producers. Policy recommendations include enhanced monitoring systems, increased access to financial and technical resources for small-scale farmers, and market diversification to improve resilience against environmental disruptions.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"144 ","pages":"Article 102821"},"PeriodicalIF":5.5,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143488267","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Assessment of the sub-lethal impacts of Karenia brevis on hard clams, Mercenaria campechiensis","authors":"Jessica Donaldson ,&nbsp;Aileen Maldonado ,&nbsp;Joseph H Bisesi ,&nbsp;William Geisbert ,&nbsp;Richard H Pierce","doi":"10.1016/j.hal.2025.102820","DOIUrl":"10.1016/j.hal.2025.102820","url":null,"abstract":"<div><div><em>Karenia brevis,</em> a toxin-producing dinoflagellate, has been implicated in frequent harmful algal blooms (HABs) in the Gulf of Mexico. Shellfish species, such as <em>Mercenaria campechiensis,</em> have high resilience to <em>K. brevis</em> exposure causing high accumulation and retention of brevetoxins within their tissues. The current study aimed to analyze the accumulation and depuration of brevetoxins in <em>M. campechiensis</em> exposed to 100,000 cells L^-1 for two weeks. The second aim was to identify the potential detoxification enzymes in <em>M. campechiensis</em> as well as potential enzymes representative of stress to see if moderate concentrations lead to stress in exposed <em>M. campechiensis.</em> This was done by exposing <em>M. campechiensis</em> to a continuous flow of <em>K. brevis</em>, followed by a 47-day depuration period. There was an increase in brevetoxin concentration during the exposure with a rapid decrease at the onset of the depuration period. This was followed by a gradual decrease with detectable toxins in the exposed clam tissue for the duration of the experiment. While there was detectable toxin during the depurations, the concentrations were below the NSP level for BTX-2 by day 14 indicating <em>M. campechiensis</em> would potentially be safe for consumption after two weeks following exposure to a moderate <em>K. brevis</em> concentration. Fold change of AChE activity significantly increased in the exposure tank when compared to the controls following the exposure period. Fold change of GST activity from control significantly decreased in the exposure tank compared to the controls on 14 d exposure. Both changes in enzyme activity support the findings that a moderate concentration of <em>K. brevis</em> may induce stress in <em>M. campechiensis.</em> Ultimately, the results of the current study further highlight the importance of the <em>K. brevis</em> regulatory limits as it can prevent possible neurotoxic shellfish poisoning in people who eat contaminated shellfish as it prevents the consumption of shellfish exposed to moderate and high concentrations of <em>K. brevis.</em></div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"143 ","pages":"Article 102820"},"PeriodicalIF":5.5,"publicationDate":"2025-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143445582","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":"The cytotoxic and hemolytic potential of karmitoxin from Karlodinium armiger and how it interacts with sterols","authors":"Hélène-Christine Prause ,&nbsp;Nadine Hochmayr ,&nbsp;Yanan Yu ,&nbsp;Thomas Ostenfeld Larsen ,&nbsp;Per Juel Hansen ,&nbsp;Giorgia Del Favero ,&nbsp;Doris Marko ,&nbsp;Allen Place ,&nbsp;Elisabeth Varga","doi":"10.1016/j.hal.2025.102817","DOIUrl":"10.1016/j.hal.2025.102817","url":null,"abstract":"<div><div>Karmitoxin, produced by <em>Karlodinium armiger</em>, is structurally related to karlotoxin and amphidinols, two potent ichthyotoxic hemolysins with high affinity for sterols. Given these structural similarities, karmitoxin is believed to exhibit comparable toxic effects. Cytotoxicity was assessed in the fish gill cell line RTgill-W1 and the human epithelial colon cell line HCEC-1CT. The hemolytic potential with and without added sterols was tested on fish erythrocytes to investigate possible impacts of toxin-sterol interactions. Sterol interactions were further evaluated using surface plasmon resonance. A 3-h incubation returned an EC₅₀ of 111 and 175 nM in RTgill-W1 and in HCEC-1CT cells, respectively. Lactate dehydrogenase (LDH) release increased with toxin concentration, reaching 11 % in the fish and 40 % in the human cell line. Extended exposure (24 h) increased the toxicity in RTgill-W1 cells (EC₅₀ 74 nM, 40 % LDH release). In parallel, hemolytic potential of karmitoxin was confirmed, as well as its interaction with free sterols. Interaction kinetics revealed complex stabilities with k_d(s⁻¹) constants of 1.13 × 10⁻² (cholesterol), 5.48 × 10⁻³ (epicholesterol), and 4.72 × 10⁻³ (ergosterol). Interaction with cholesterol followed the single-exponential model well, while data indicated more complex binding with epicholesterol and ergosterol. Altering the RTgill-W1 cholesterol content did not impact cytotoxicity at the tested concentration. Overall, karmitoxin showed potent cytotoxic and hemolytic properties in human and fish models. Complex formation with sterols may play a role in membrane targeting, yet cellular cholesterol quantity might not affect cytotoxicity.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"143 ","pages":"Article 102817"},"PeriodicalIF":5.5,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143419526","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Nutrient limitation and seasonality associated with phytoplankton communities and cyanotoxin production in a large, hypereutrophic lake","authors":"Gabriella M. Lawson ,&nbsp;Jakob L. Young ,&nbsp;Zachary T. Aanderud ,&nbsp;Erin F. Jones ,&nbsp;Samuel Bratsman ,&nbsp;Jonathan Daniels ,&nbsp;Madeleine P. Malmfeldt ,&nbsp;Michelle A. Baker ,&nbsp;Benjamin W. Abbott ,&nbsp;Scott Daly ,&nbsp;Hans W. Paerl ,&nbsp;Greg Carling ,&nbsp;Brian Brown ,&nbsp;Raymond Lee ,&nbsp;Rachel L. Wood","doi":"10.1016/j.hal.2025.102809","DOIUrl":"10.1016/j.hal.2025.102809","url":null,"abstract":"<div><div>Though freshwater harmful algal blooms have been described and studied for decades, several important dynamics remain uncertain, including the relationships among nutrient concentrations, phytoplankton growth, and cyanotoxin production. To identify when and where nutrients limit phytoplankton, cyanobacteria, and cyanotoxins, we conducted in situ bioassay studies. We added nitrogen (N), phosphorus (P), or N + P across various seasons in water collected from three locations across Utah Lake, one of the largest freshwater lakes in the western U.S. This shallow, hypereutrophic lake provides a powerful testbed for quantifying nutrient-growth-toxin interactions. We assessed a range of parameters over time, including photopigment concentrations, phytoplankton abundance (cell counts), cyanotoxins, and nutrient concentrations. Despite high background nutrient concentrations in lake water, phytoplankton abundance and composition were strongly affected by nutrient addition. Phosphorus limitation was more common in the spring, with N limitation and N + P limitation becoming more common in the fall. Nutrient additions were positively associated with cyanobacteria (<em>Microcystis, Aphanocapsa, Dolichospermum, Merismopedia, Aphanizomenon</em> spp<em>.</em>), eukaryotes (<em>Aulacoseira, Desmodesmus</em> spp<em>.</em>), and two taxonomical categories of phytoplankton (i.e., unicellular and colonial green algae). When detected, anatoxin-a was positively associated with <em>Aphanizomenon</em> and negatively associated with <em>Microcystis</em> spp. However, overall cyanotoxin concentrations were not associated with cyanobacterial cell density but varied seasonally. These findings highlight the importance of considering seasonal nutrient availability dynamics and provide insights into specific nutrient targets, species, and cyanotoxins that play a significant role in the health and management of similar eutrophic lake environments around the world.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"143 ","pages":"Article 102809"},"PeriodicalIF":5.5,"publicationDate":"2025-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143403516","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Intraspecific variability within Karlodinium armiger (Dinophyceae) on a toxicological and metabolomic level","authors":"Magdalena Pöchhacker ,&nbsp;Urban Tillmann ,&nbsp;Doris Marko ,&nbsp;Elisabeth Varga","doi":"10.1016/j.hal.2025.102808","DOIUrl":"10.1016/j.hal.2025.102808","url":null,"abstract":"<div><div>The species <em>Karlodinium armiger</em> occasionally co-occurs with <em>Karlodinium veneficum</em> during harmful algal blooms. The only toxin of this species described so far is karmitoxin, a highly ichthyotoxic compound very similar to the karlotoxins produced by <em>K. veneficum</em>. However, information on <em>K. armiger</em> is limited and based on a single Mediterranean strain (K-0668), with few studies investigating its toxicity. Given the high intraspecific variability known in <em>K. veneficum</em>, it was a significant achievement when two additional strains of <em>K. armiger</em> (MD-D6 and MD-D7) were isolated from the Labrador Sea in 2017, enabling comparative studies within this species. The toxicity of these three strains was assessed using the fish gill cell line RTgill-W1 and the cryptophyte <em>Rhodomonas salina</em>. An untargeted metabolomics approach using high-resolution tandem mass spectrometry, along with a computational workflow, provided insights into the metabolomic differences between the strains. Despite being cultivated under identical conditions, the metabolomic profiles and toxicological properties were distinct, even between MD-D6 and MD-D7, which were isolated from the same water sample. While MD-D7 did not exhibit significant toxicity, MD-D6 showed high toxicity and lytic potential, similar to K-0668. Interestingly, karmitoxin was only detected in K-0668, and neither karlotoxins nor any known analogs were detected in any strain. Within this comprehensive workflow, some molecules were found in MD-D6 that share the same chemical space as karmitoxin, making them interesting targets for further research. In conclusion, this study evaluated the toxicological and metabolic variability in three different strains of <em>K. armiger</em> and identified some putative toxin candidates in MD-D6.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"143 ","pages":"Article 102808"},"PeriodicalIF":5.5,"publicationDate":"2025-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143403515","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Role of benthic overwintering cyanobacteria seed stock on estuarine bloom dynamics","authors":"Ellen P. Preece ,&nbsp;Timothy G. Otten ,&nbsp;Janis Cooke ,&nbsp;Katherine V. Cook","doi":"10.1016/j.hal.2025.102807","DOIUrl":"10.1016/j.hal.2025.102807","url":null,"abstract":"<div><div>Cyanobacteria blooms (cHABs) comprised of the potentially toxic cyanobacterium <em>Microcystis</em>, are increasing in waterbodies worldwide. CHABs in estuaries often originate from upstream locations with longer hydraulic residence times (e.g., reservoirs, static channels). These locations also accumulate higher concentrations of benthic overwintering cells that serve as inoculum for subsequent year's blooms. We investigated overwintering <em>Microcystis</em> seed stock in the hydrologically complex upper San Francisco Estuary also known as the Sacramento-San Joaquin Delta (Delta). Quantitative polymerase chain reaction (qPCR) was used to quantify total <em>Microcystis</em> in the sediments that was available to inoculate summertime blooms. To study bloom origin and succession, DNA from discrete water and sediment samples was PCR amplified using cyanobacteria-specific 16S-23S ITS rDNA primers. Results confirmed the hypothesis that static peripheral areas have the highest seed stock and generally the highest <em>Microcystis</em> concentrations in surface water. We also confirmed high genetic diversity of the <em>Microcystis</em> population in the Delta with 36 unique genotypes detected in the sediment and water column. This study demonstrates that overwintering cells should be considered when investigating <em>Microcystis</em> dynamics across large estuarine systems.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"143 ","pages":"Article 102807"},"PeriodicalIF":5.5,"publicationDate":"2025-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143395514","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Detection of a late autumn Karenia papilionacea bloom in Virginia, USA, coastal waters","authors":"Jennifer L. Wolny ,&nbsp;Michelle C. Tomlinson ,&nbsp;Todd A. Egerton ,&nbsp;Leah A. Gibala-Smith ,&nbsp;Chyna B. Law ,&nbsp;Ellen Gortz ,&nbsp;Emma W. Brooks ,&nbsp;Edward B. Whereat ,&nbsp;Margaret R. Mulholland","doi":"10.1016/j.hal.2025.102805","DOIUrl":"10.1016/j.hal.2025.102805","url":null,"abstract":"<div><div>A late autumn <em>Karenia papilionacea</em> bloom was detected within Virginia, USA shellfish harvesting areas in mid-November 2023. Using Imaging FlowCytobot (IFCB) data collected during the Northeast Fisheries Science Center Ecosystem Monitoring October – November 2023 cruise, we were able to document a larger <em>Karenia</em> bloom composed of <em>K. papilionacea, K. brevis</em>-like<em>, K. mikimotoi,</em> and <em>Karenia</em> sp. #3 cells offshore of Virginia three weeks prior to detection inshore. Both <em>K. papilionacea</em> and <em>K. mikimotoi</em> were detected in Virginia state waters (including shellfish harvesting areas) and offshore waters of the Delmarva Peninsula, whereas <em>K. brevis</em>-like and <em>Karenia</em> sp. #3 were only detected offshore. The IFCB data showed that along the cruise track the greatest cell concentrations were east of the Chesapeake Bay mouth on November 1, 2023. However, when conducting a match-up assessment of IFCB <em>in situ</em> data with Sentinel-3 Ocean and Land Colour Instrument (OLCI) satellite imagery using the Red Band Difference (RBD) algorithm, the majority of the bloom was undetected. By comparing <em>in situ</em> match-ups and RBD imagery with NOAA-20 satellite's Visible Infrared Imaging Radiometer Suite (VIIRS) chlorophyll anomaly product we hypothesize that the <em>in situ</em> sampling occurred along the bloom's edge, where cell concentrations were at or below the limit of satellite detection, and/or this particular <em>Karenia</em> bloom was either not fluorescing, expressing relatively low solar-induced chlorophyll fluorescence, or occurring at depths below satellite detection. For this bloom event, the IFCB dataset was also used as a training tool for students learning microscopy-based phytoplankton identification in a virtual environment.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"142 ","pages":"Article 102805"},"PeriodicalIF":5.5,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143144160","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":"Cyanobacteria alter lipid metabolism in zooplankton via exudates of obesogens","authors":"Jinlong Zhang ,&nbsp;Xuexiu Chang ,&nbsp;Hugh J. MacIsaac ,&nbsp;Yuan Zhou ,&nbsp;Daochun Xu ,&nbsp;Jingjing Li ,&nbsp;Jun Xu ,&nbsp;Tao Wang ,&nbsp;Hongyan Zhang ,&nbsp;Zimeng Peng ,&nbsp;Jiayao Wen ,&nbsp;Runbing Xu","doi":"10.1016/j.hal.2024.102790","DOIUrl":"10.1016/j.hal.2024.102790","url":null,"abstract":"<div><div>Lipid metabolism of zooplankton plays an important role in aquatic food web, however, is threatened by abiotic and biotic factors. Recently blooming cyanobacteria providing low-quality food for zooplankton, have been found to be a potential source of lipid metabolism disorder and reproductive disturbance in aquatic animals, though mechanisms of operation are unclear. Here we assessed effects of cyanobacterial exudates on lipid metabolism and reproduction in <em>Daphnia magna. Microcystis aeruginosa</em> exudates (MaE, 2 × 10⁴ cells/mL and 4 × 10⁵cells/mL) induced increased lipid droplets and altered lipid components in exposed <em>Daphnia</em>. MaE activated ecdysone and juvenile hormone signaling pathways by increasing hormone content and activities of ecdysone receptor and steroid receptor coactivator, which stimulated sterol regulatory element binding protein to increase lipid accumulation. MaE also increased expression of <em>ECR, HR3, Neverland</em> and <em>RXR</em> genes in the ecdysone pathway, <em>Met</em> and <em>SRC</em> genes in the juvenile hormone pathway, and <em>SREBP-1</em> and <em>DGAT-1</em> genes in the triacylglycerol (TAG) synthesis pathway. The increase in lipid production promoted both reproduction and growth of <em>Daphnia</em>. Glycerol tristearate (GTS, a TAG lipid species) in MaE solutions was positively correlated with cholesterol, TAG, and reproductive hormones in exposed <em>Daphnia</em>. Disordered lipid metabolism of zooplankton caused by cyanobacteria exudates is consistent with obesogen hypothesis (Baillie-Hamilton, 2002) and poses a risk to aquatic ecosystems.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"142 ","pages":"Article 102790"},"PeriodicalIF":5.5,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143144162","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}