Harmful Algae最新文献

{"title":"Sargassum influxes in West Africa: Impacts, challenges, and prospects for sustainable management","authors":"Abdulwakil Olawale Saba ,&nbsp;Kafayat Adetoun Fakoya ,&nbsp;Lucette Adet ,&nbsp;Hussein Aliu Sule ,&nbsp;Akinloye Emmanuel Ojewole ,&nbsp;Nimah Folake Osho-Abdulgafar","doi":"10.1016/j.hal.2025.102982","DOIUrl":"10.1016/j.hal.2025.102982","url":null,"abstract":"<div><div>The causes and mechanisms behind the influx of <em>Sargassum</em> in West Africa are poorly understood. The lack of effective management and control measures negatively impacts fishing, tourism, and marine life, leaving coastal communities with insufficient adaptive strategies. Research on <em>Sargassum</em> in the region is limited, which may lead to an underestimation of the socio-economic impacts of the blooms. Regional efforts led by the Abidjan Convention Secretariat and the United Nations Environment Programme (UNEP) have yet to yield significant results. There are considerable gaps in funding, policy prioritization, capacity building, and access to technology for early detection and monitoring, all of which are essential for implementing an effective <em>Sargassum</em> management strategy. Between 2018 and 2023, estimates of stranded biomass across the tropical Atlantic ranged from 2 to 10 million tons annually, with West Africa contributing a smaller yet still significant share. The biochemical composition of West African <em>Sargassum</em> demonstrates some economic potential, though heavy metal contamination and monitoring challenges limit use, necessitating the need for targeted management and detoxification efforts. While <em>Sargassum</em> presents opportunities for innovation and sustainable economic use, resources for developing regional value chains are scarce. West Africa could benefit from a more deliberate collaborative transatlantic partnership, as well as from strengthening an integrated regional strategy to create scalable and sustainable solutions in research, policy, management, and practical applications.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"150 ","pages":"Article 102982"},"PeriodicalIF":4.5,"publicationDate":"2025-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145106560","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":"Harmful algal bloom species identified in the East China Sea through metabarcoding analysis of large-scale sampling expedition","authors":"Yang Chen ,&nbsp;Shuya Liu ,&nbsp;Nansheng Chen","doi":"10.1016/j.hal.2025.102977","DOIUrl":"10.1016/j.hal.2025.102977","url":null,"abstract":"<div><div>East China Sea (ECS) is known for its frequent occurrences of harmful algal blooms (HABs) especially in spring, many of which are toxigenic. In this study, we identified HAB species through metabarcoding analysis of 178 water samples collected from 44 sampling sites at different depths in the continental shelf of ECS in spring of 2019. Through amplicon sequence variant (ASV)-based metabarcoding analysis, we identified 3896 ASVs representing 32 classes in six phytoplankton phyla/divisions, among which Dinoflagellata was the most dominant phylum. Among 244 phytoplankton species annotated in this study, 67 HAB species were identified, of which 29 species having the potential to produce toxin. Many of these identified HAB species displayed unique spatial distribution patterns. Phylogenetic network analysis revealed rich molecular diversity of <em>Prorocentrum, Alexandrium</em> and <em>Pseudo-nitzschia</em> genera. Temperature and NO₃^- both showed significant correlations with most phytoplankton phyla (<em>p</em> &lt; 0.01), while PO₄^3- exhibited significant correlations with the dominant HAB species <em>Chaetoceros tenuissimus</em> (<em>p</em> &lt; 0.05) and <em>Scrippsiella trochoidea</em> (<em>p</em> &lt; 0.01). Clearly, these environmental factors play a key role in influencing the distribution of phytoplankton species in ECS. This study represents the first large-scale attempt in identifying HAB species in ECS in spring through ASV-based metabarcoding analysis. Results from this study will facilitate further comparative research on the molecular diversity and biogeography of HAB species, and monitoring HAB events in ECS.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"150 ","pages":"Article 102977"},"PeriodicalIF":4.5,"publicationDate":"2025-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145106561","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":"Rare cyanobacteria drive nitrogen-fixation and cyanotoxin production in an Aphanizomenon-dominated bloom","authors":"Kaela E. Natwora ,&nbsp;Adam J. Heathcote ,&nbsp;Mark B. Edlund ,&nbsp;Shane E. Bowe ,&nbsp;Benjamin J. Kramer ,&nbsp;Jake D. Callaghan ,&nbsp;Cody S. Sheik","doi":"10.1016/j.hal.2025.102978","DOIUrl":"10.1016/j.hal.2025.102978","url":null,"abstract":"<div><div>Late summer, recurring cyanobacterial blooms in Lake of the Woods (LOW) are polycyanobacterial and typically dominated by <em>Aphanizomenon flos-aquae</em>. LOW waters are typically nitrogen limited, relative to phosphorus. As such, the dominance of <em>Aphanizomenon flos-aquae,</em> a putative nitrogen-fixing cyanobacterium, suggests that its ability to fix nitrogen may be advantageous and aid in its ability to bloom. This study sought to quantify nitrogen fixation rates and identify cyanotoxin-producing species during the blooms. Throughout the 2021 season, we quantified nutrients, N-fixation rates, microbial community composition, and gene expression to determine who is responsible for cyanotoxin synthesis and nitrogen fixation. We found nitrogen fixation rates increased throughout the season, coincided with the bloom, but likely cannot fully support the bloom’s nitrogen demand. However, the transcription of nitrogenase genes was solely done by less abundant <em>Dolichospermum</em> spp. and not by <em>A. flos-aquae.</em> Genome analysis suggests this population of <em>A. flos-aquae</em> cannot create a functioning nitrogenase, but they do still express the genes to initiate heterocyst differentiation. Microcystin gene transcripts were primarily from <em>Microcystis</em> spp. and <em>Planktothrix</em> spp. and coincided with microcystin concentrations. Interestingly, <em>Planktothrix</em> highly expressed anabaenopeptin genes, suggesting the presence of additional bioactive compounds in LOW. This work suggests that rare cyanobacterial members drive nitrogen fixation, and may be necessary for the seasonal bloom’s function, toxicity, and longevity.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"150 ","pages":"Article 102978"},"PeriodicalIF":4.5,"publicationDate":"2025-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145106562","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":"Insights into the in vitro ichthyotoxicity on fish gill cells and toxin production of Karlodinium veneficum (Dinophyceae) strains from French waters","authors":"Rima Beesoo ,&nbsp;Kevin Hogeveen ,&nbsp;Fabienne Hervé ,&nbsp;Damien Réveillon ,&nbsp;Clémence Boucher ,&nbsp;Stéphanie Auzoux-Bordenave ,&nbsp;Valérie Fessard ,&nbsp;Roberto A. Avelar ,&nbsp;Nicolas Chomérat ,&nbsp;Gwenael Bilien ,&nbsp;Malwenn Lassudrie","doi":"10.1016/j.hal.2025.102980","DOIUrl":"10.1016/j.hal.2025.102980","url":null,"abstract":"<div><div>The dinoflagellate <em>Karlodinium veneficum</em> is regularly detected in French coastal waters; however, the ichthyotoxic potential of French strains and their ability to produce karlotoxins (KmTxs) remain unclear. This study aims to compare the bioactivity and KmTx profiles of four French strains and one previously characterized American strain of <em>K. veneficum</em> (used here as a reference), using the RTgill-W1 rainbow trout gill cell line. Both intracellular and releasable toxins (INT, EXT) in methanolic extracts were assessed for their effects using a resazurin-based assay, lactate dehydrogenase (LDH) release, mitochondrial membrane potential (TMRE dye), while liquid chromatography coupled to mass spectrometry was used to detect KmTxs. Cytotoxic activity varied depending on the strain and fraction, with IFR-CC-20–44 EXT (French) and CCMP 2936 INT (American) being the most toxic, while CBC7 (French) showed no toxicity. The French strains generally exhibited different cytotoxic mechanisms compared to the American strain. The KmTx profiles of the toxic strains showed an unexpectedly high chemodiversity with 93 KmTx-like molecules detected. Three French strains had similar KmTx profiles, dominated by KmTx-5 and a KmTx-5 analog. In contrast, the KmTx profile of the American CCMP 2936 was completely different to the French strains, with no KmTx in common. Interestingly, strain CBC7, which was non-toxic, did not produce any KmTxs. However, among the other <em>K. veneficum</em> strains, no clear link was established between the cytotoxicity of their extracts and total KmTx content. This may reflect differences in potency among KmTx analogs, although the involvement of other uncharacterized compounds cannot be excluded.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"150 ","pages":"Article 102980"},"PeriodicalIF":4.5,"publicationDate":"2025-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145106955","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":"A modeling investigation into the ecological role of mixotrophy in Karenia brevis blooms on the West Florida Shelf","authors":"Yuren Chen ,&nbsp;Ming Li ,&nbsp;Patricia M. Glibert ,&nbsp;Cynthia Heil ,&nbsp;So Hyun Ahn","doi":"10.1016/j.hal.2025.102979","DOIUrl":"10.1016/j.hal.2025.102979","url":null,"abstract":"<div><div>While laboratory experiments show <em>Karenia brevis</em> graze on <em>Synechococcus</em> to supplement nutrition, the ecological role of mixotrophy in <em>K. brevis</em> blooms on the West Florida Shelf remains unquantified. This study employs a three-dimensional coupled hydrodynamic-biogeochemical model to investigate the contribution of mixotrophic feeding to the <em>K. brevis</em> growth as well as the role of mixotrophic grazing in suppressing prey population and delivering a competitive advantage to the mixotroph. It is shown that mixotrophy moderately increased the growth rate of <em>K. brevis</em> in the bloom center but was important along the offshore margin of the bloom region, where the prey-to-predator ratio was high. With the digestion rate reaching over 200 prey cells <em>K. brevis</em>^-1 day^-1, mixotrophy could support a heterotrophic growth rate of up to 0.16 day^-1 in the offshore region and may facilitate the offshore expansion of <em>K. brevis</em> blooms. Mixotrophic feeding also played a significant role in sustaining the <em>K. brevis</em> bloom during the late spring and summer periods when the inorganic nutrient concentrations were low. The grazing pressure exerted on <em>Synechococcus</em> was found to be vital for the slow-growing <em>K. brevis</em> to outcompete the oligotrophic-adapted prey. These model results demonstrate that mixotrophy not only functions as an additional nutrient source but also as an ecological mechanism that can reshape interspecific competition and harmful algal bloom dynamics.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"150 ","pages":"Article 102979"},"PeriodicalIF":4.5,"publicationDate":"2025-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145106563","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":"Application of a hydrodynamic model to long-term monitoring data: exploring transport pathways to identify the source of high toxicity populations of Dinophysis fortii in aquaculture sites in northern Japan","authors":"Akira Miyazono ,&nbsp;Takanori Kuribayashi ,&nbsp;Yasufumi Hada ,&nbsp;Ken Asakura ,&nbsp;Kazuma Kobayashi ,&nbsp;Katsuhiko Mizuno ,&nbsp;Wai Mun Lum ,&nbsp;Sirje Sildever ,&nbsp;Hiroshi Kuroda ,&nbsp;Satoshi Nagai","doi":"10.1016/j.hal.2025.102976","DOIUrl":"10.1016/j.hal.2025.102976","url":null,"abstract":"<div><div>Diarrhetic Shellfish Toxicity (DST) occurs in northern Japan, Hokkaido and Tohoku, and is rarely observed in the southwest. A recent study using cultured strains of <em>Dinophysis fortii</em> revealed that high toxicity (HT) strains exist in northern Japan, while low-toxicity (LT) strains are found in the southwest. In this study, we analyzed 40 years of DST and plankton monitoring data from Hokkaido, eight years from Akita Prefecture, 33 years of oceanographic data from the Sea of Japan off northern Hokkaido, and the results of an ocean model experiment. The relationship between the annual DST maximum value and the cell density of <em>D. fortii</em> maxima in Hokkaido suggests the presence of both HT and LT strains. Results from the particle tracking experiment showed that transport of offshore populations of <em>D. fortii</em> to the coast is a key factor in HT DST events. Oceanographic data support that high DST along the Sea of Japan coasts in northern Hokkaido occurs in years of strong influence of the subarctic water of the Sea of Japan (SWSOJ). In northwestern Japan (Akita Prefecture), HT DST events were detected in years with strong influence of the second and third components of the Tsushima Warm Current (TWC2, 3) transporting particles from the SWSOJ. These results led to the conclusion that i) HT strains of <em>D. fortii</em> are transported by the SWSOJ reaching Hokkaido via its extension and Akita via the TWC2, 3, and ii) LT strains are transported to northern Japan via the first component of the Tsushima Warm Current (TWC1).</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"150 ","pages":"Article 102976"},"PeriodicalIF":4.5,"publicationDate":"2025-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145059938","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":"Diversity of amphidomatacean dinoflagellates in Japan, with a description of Azadinium inconspicuum sp. nov. and azaspiracid components in Azadinium poporum ribotypes","authors":"Koyo Kuwata ,&nbsp;Wai Mun Lum ,&nbsp;Kazuya Takahashi ,&nbsp;Garry Benico ,&nbsp;Mayu Ozawa ,&nbsp;Hajime Uchida ,&nbsp;Satoshi Numano ,&nbsp;Ryuichi Watanabe ,&nbsp;Ryoji Matsushima ,&nbsp;Toshiyuki Suzuki ,&nbsp;Mitsunori Iwataki","doi":"10.1016/j.hal.2025.102969","DOIUrl":"10.1016/j.hal.2025.102969","url":null,"abstract":"<div><div>Species diversity of amphidomatacean dinoflagellates belonging to <em>Azadinium</em> and <em>Amphidoma</em> 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, <em>Azadinium caudatum, Az. cuneatum, Az. dexteroporum</em>, and <em>Az. spinosum</em> were newly found in the Northwest Pacific, <em>Az. dalianense</em> was the first report in Japan, and <em>Azadinium inconspicuum</em> sp. nov. was a new species described in this study. <em>Azadinium inconspicuum</em> independently branched in the clade of <em>Az. dexteroporum/Az. galwayense</em>/<em>Az. perfusorium</em> but differed from <em>Az. dexteroporum</em> in shape of the Po plate (absent vs. present of the finger-like protrusion), from <em>Az. galwayense</em> in shape of the 2a plate (four- vs. five-sided), and from <em>Az. perfusorium</em> in position of pyrenoid (in the episome vs. at the antapex). It had a close resemblance to <em>Az. luciferelloides</em> in thecal morphology, but differed in detailed position of the ventral pore and shape of the posterior sulcal plate. Azaspiracids (AZAs) were detected in <em>Azadinium poporum</em> and <em>Az. spinosum</em>, but no trace was found in other amphidomatacean cultures, including <em>Az. dexteroporum</em>. Among 81 cultures examined, 47 cultures were assigned to <em>Az. poporum</em>, and belonged to four intraspecific ribotypes. Major AZA components in Japanese <em>Az. poporum</em> 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 <em>Az. poporum</em>, particularly in ribotype C1, where high AZA amounts were detected, is the major AZA-producer along the Japanese coastal waters.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"150 ","pages":"Article 102969"},"PeriodicalIF":4.5,"publicationDate":"2025-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145047227","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":"Simplifying marine biotoxin data analysis: Advancing the Neuro-2a cell-based assay using R","authors":"Synne T. Frøstrup ,&nbsp;Christian Ritz ,&nbsp;Oliver Kappenstein ,&nbsp;Astrid Spielmeyer ,&nbsp;Christopher R. Loeffler","doi":"10.1016/j.hal.2025.102968","DOIUrl":"10.1016/j.hal.2025.102968","url":null,"abstract":"<div><div>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, <em>n2a</em>, 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 <em>n2a</em> 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.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"150 ","pages":"Article 102968"},"PeriodicalIF":4.5,"publicationDate":"2025-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145026326","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":"Combined effects of CO2 and nitrogen on the stoichiometry of toxin synthesis in a harmful cyanobacterium","authors":"Savannah Sarkis ,&nbsp;Jing Liu ,&nbsp;Jef Huisman ,&nbsp;Uwe John ,&nbsp;Jolanda M.H. Verspagen ,&nbsp;Dedmer B. Van de Waal","doi":"10.1016/j.hal.2025.102964","DOIUrl":"10.1016/j.hal.2025.102964","url":null,"abstract":"<div><div>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. <em>Microcystis</em> 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 <em>Microcystis aeruginosa</em> 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.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"150 ","pages":"Article 102964"},"PeriodicalIF":4.5,"publicationDate":"2025-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145059939","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":"Ship-based eDNA tracking unveils early dispersal patterns and microecological dynamics of Ulva prolifera micropropagules in yellow sea green tide outbreaks","authors":"Runze Chen ,&nbsp;Yinqing Zeng ,&nbsp;Caihua Yao ,&nbsp;Faqing He ,&nbsp;Shulin Tan ,&nbsp;Yutao Qin ,&nbsp;Huanhong Ji ,&nbsp;Lihua Xia ,&nbsp;Lining Xia ,&nbsp;Yuru Yan ,&nbsp;Peimin He ,&nbsp;Jianheng Zhang","doi":"10.1016/j.hal.2025.102966","DOIUrl":"10.1016/j.hal.2025.102966","url":null,"abstract":"<div><div>Green tides caused by <em>Ulva prolifera</em> in the South Yellow Sea (SYS) pose significant ecological and economic threats. <em>Neopyropia</em> 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 <em>U. prolifera</em> 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 <em>U. prolifera</em> in development areas of Yellow Sea green tide, using eDNA technology combined with environmental parameters. Surveys in April and June 2024 across <em>Neopyropia</em> raft-farming (RD transect) and non-raft (SY transect) areas revealed ecological differences during early green tide development. Key findings include:(1) In April, <em>U. prolifera</em> 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 <em>U. prolifera</em> eDNA in June. (2) High <em>U. prolifera</em> 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 <em>U. prolifera</em>. The identification of <em>Pirsonia</em> sp. and other species provides a new perspective for elucidating the competitive mechanisms underlying early-stage <em>U. prolifera</em> 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.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"150 ","pages":"Article 102966"},"PeriodicalIF":4.5,"publicationDate":"2025-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145020298","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}