Harmful Algae最新文献

{"title":"Assessing the genomic diversity of a NW Spain bloom of Alexandrium minutum using satDNAs as chromosomal markers","authors":"Ángeles Cuadrado ,&nbsp;Marta Sixto ,&nbsp;Rosa Isabel Figueroa ,&nbsp;Alfredo de Bustos","doi":"10.1016/j.hal.2025.102801","DOIUrl":"10.1016/j.hal.2025.102801","url":null,"abstract":"<div><div><em>Alexandrium minutum</em> is a toxic dinoflagellate with numerous strains known to produce paralytic shellfish toxins (PSTs). Given the ecological importance and socio-economic impact of <em>A. minutum</em> blooms in coastal waters worldwide, this study assesses the genomic diversity by analysing clonal cultures obtained from an exceptional <em>A. minutum</em> red tide event that occurred in the Ría de Vigo (NW Atlantic coast of Spain) in 2018. To our knowledge this is the first time that satellite DNAs (satDNAs) has been used as chromosomal markers by fluorescence in situ hybridization (FISH) to analyse genomic diversity in a bloom. AmSat002-6, which is monomorphic, and AmiSat017-88 and AmiSat059-512, which colocalized with 45S rDNA can be used as markers to investigate the role of sexuality and its potential role in blooms and other factors that may influence the life cycle of <em>A. minutum</em>. Four satDNAs (AmiSat021-510, AmiSat041-75, AmiSat048-3-AAG and AmiSat060-65) are polymorphic and were used to genotype twelve clonal strains isolated from seven sites over three weeks. In addition, three <em>A. minutum</em> strains from different Mediterranean origins were genotyped. Each strain was distinguished by its unique four-satDNA genotype. Clustering and similarity analyses did not reveal any spatial or temporal grouping of the bloom strains; the dispersion was even greater than the dispersion among the Mediterranean strains, which lay between the bloom strains. The differences in the FISH patterns of sat-DNA within <em>A. minutum</em> may contribute to the assessment of genus diversification.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"142 ","pages":"Article 102801"},"PeriodicalIF":5.5,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143144163","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":"Effects of the salinity on the growth, hemolytic activity, fatty acid content, and expression of polyketide synthase and fatty acid synthase genes of Amphidinium carterae (Dinophyceae)","authors":"Armando Mendoza-Flores ,&nbsp;Clara Elizabeth Galindo-Sánchez ,&nbsp;M. del Pilar Sánchez-Saavedra","doi":"10.1016/j.hal.2024.102788","DOIUrl":"10.1016/j.hal.2024.102788","url":null,"abstract":"<div><div>The benthic dinoflagellate <em>Amphidinium carterae</em> can produce fatty acids and polyketide compounds, such as amphidinols. Commonly, polyketides are produced by polyketides synthase (PKS), and fatty acids are produced by fatty acids synthase (FAS). The PKS and FAS genes in dinoflagellates share a common evolutionary history. This study aimed to investigate the effect of five salinities (20, 25, 30, 35, and 40 ‰) on growth, fatty acid content, hemolytic activity, and the expression of PKS and FAS genes. The results showed that low salinity (20 ‰) induces low growth in <em>A. carterae.</em> Cell size was affected by salinity, with a decrease in cell size with the salinity increase. The content of fatty acids and hemolytic compounds content increased at low salinities (20 and 25 ‰). The gene expression of the PKS genes was upregulated at high salinities (35 and 40 ‰) and downregulated at low salinities (20 and 25 ‰); FAS genes were downregulated at high (40 ‰) and low (20 ‰) salinities. The low growth rate at low salinity (20 ‰) and the high content of fatty acids and hemolytic compounds in low salinities (20 and 25 ‰) indicate that low salinities caused stress in this strain of <em>A. carterae.</em> The hemolytic activity at salinity of 20 ‰ probably due to a combinatory effect of high content of polyunsaturated fatty acids and amphidinols. To understand the relationship between gene expression and amphidinols biosynthesis requires the analysis of single-domain and multi-domain PKS.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"142 ","pages":"Article 102788"},"PeriodicalIF":5.5,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143143515","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":"Effects of copepod chemical cues on intra- and extracellular toxins in two species of Dinophysis","authors":"Milad Pourdanandeh ,&nbsp;Véronique Séchet ,&nbsp;Liliane Carpentier ,&nbsp;Damien Réveillon ,&nbsp;Fabienne Hervé ,&nbsp;Clarisse Hubert ,&nbsp;Philipp Hess ,&nbsp;Erik Selander","doi":"10.1016/j.hal.2024.102793","DOIUrl":"10.1016/j.hal.2024.102793","url":null,"abstract":"<div><div>Copepods may contribute to harmful algal bloom formation by selectively rejecting harmful cells. Additionally, copepods and the chemical cues they exude, copepodamides, have been shown to induce increased toxin production in paralytic and amnesic toxin producing microalgae. However, it is unknown if diarrhetic shellfish toxin (DST) producers such as <em>Dinophysis</em> respond to copepods or copepodamides in a similar fashion. Here we expose laboratory cultures of <em>Dinophysis sacculus</em> and <em>D. acuminata</em> to direct grazing by <em>Acartia</em> sp. copepods or copepodamides and measure their toxins after three days. Total <em>Dinophysis</em>-produced toxins (DPTs), okadaic acid, pectenotoxin-2, and C9-diol ester of okadaic acid, increased by 8 - 45 % in <em>D. sacculus</em> but was significantly different from controls only in the highest (10 nM) copepodamide treatment whereas toxin content was not affected in <em>D. acuminata</em>. Growth rate was low across all groups and explained up to 91 % of the variation in toxin content. DPTs were redistributed from internal compartments to the extracellular medium in the highest copepodamide treatments (5 - 10 nM), which were two to three times higher than controls and indicates an active release or passive leakage of toxins. Untargeted analysis of endometabolomes indicated significant changes in metabolite profiles for both species in response to the highest copepodamide treatments, independent of known toxins. However, it is not clear whether these are stress responses or caused by more complex mechanisms. The relatively small grazer-induced effect in <em>Dinophysis</em> observed here, compared to several species of <em>Alexandrium</em> and <em>Pseudo-nitzschia</em> reported previously, suggests that DPT production in <em>Dinophysis</em> is likely not induced by copepods, except perhaps in patches with high copepod densities. Thus, DPTs may, represent either a constitutive chemical defence for <em>Dinophysis</em>, or serve an altogether different purpose.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"142 ","pages":"Article 102793"},"PeriodicalIF":5.5,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143143553","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":"Transcriptional regulation of the cylindrospermopsin biosynthesis (cyr) gene cluster in Raphidiopsis raciborskii AWT205","authors":"Alescia Cullen ,&nbsp;Leanne A. Pearson ,&nbsp;Sarah E. Ongley ,&nbsp;Nathan D. Smith ,&nbsp;Brett A. Neilan","doi":"10.1016/j.hal.2024.102783","DOIUrl":"10.1016/j.hal.2024.102783","url":null,"abstract":"<div><div>Cyanobacterial harmful algal blooms (HABs), producing the hepatotoxin cylindrospermopsin (CYN), are among the most frequently reported globally. Although the gene cluster encoding CYN biosynthesis (<em>cyr</em>) has been sequenced, many aspects of CYN regulation are unresolved. This study investigates <em>cyr</em> transcriptional regulation in the cyanobacterium, <em>Raphidiopsis raciborskii</em> AWT205, through <em>in silico</em> analysis, reverse transcription quantitative PCR (RT-qPCR), and DNA-affinity capture assays (DACAs). While <em>in silico</em> analysis identified binding sites for environmentally responsive transcription factors throughout the <em>cyr</em> cluster, DACAs captured the binding of AbrB (a transcription factor that regulates the cyanobacterial response to nitrogen and iron availability) to the <em>cyrD</em> promoter. Surprisingly, the initiating cylindrospermopsin synthetase, CyrA, was also captured by the <em>cyrD</em> promoter probe. This is the first experimental evidence of CYN (and cyanotoxin) autoregulation. Our study is also the most extensive investigation of <em>cyr</em> transcription, concurrently targeting nine <em>cyr</em> genes across three growth stages. We found significant heterogeneity between transcription levels of each <em>cyr</em> gene, which also varied across different growth stages. Surprisingly, the ratio of <em>cyrI</em> (hydroxylase) to <em>cyrJ</em> (sulfotransferase) transcripts was inversely proportional to the ratio of deoxyCYN to CYN. Taken together, the results of this study suggest that transcription of the <em>cyr</em> gene cluster in <em>R. raciborskii</em> AWT205 is driven by multiple promoters and DNA-binding proteins, that can be responsive to changing environmental conditions. However, the production of different CYN variants did not correlate to transcription alone, with additional regulatory mechanisms proposed.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"142 ","pages":"Article 102783"},"PeriodicalIF":5.5,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143144652","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":"Control of cyanobacterial blooms with iron addition can favor stress-tolerant toxic species","authors":"Luis Aubriot ,&nbsp;Florencia Clivio ,&nbsp;Andrea Somma ,&nbsp;Elena Galvanese ,&nbsp;Sol Colombo ,&nbsp;Signe Haakonsson","doi":"10.1016/j.hal.2024.102784","DOIUrl":"10.1016/j.hal.2024.102784","url":null,"abstract":"<div><div>The control of internal phosphorus (P) load by in-lake measures has been the subject of decades of research. Although iron (Fe) is effective in precipitating P, it has been less tested due to its redox sensitivity. The effectiveness of Fe in controlling P availability and sinking cyanobacterial blooms contrasts to its function as a nutrient for phytoplankton growth. Both roles of Fe were tested in enclosures placed for 36 days in a shallow lake with a perennial cyanobacterial bloom, and in laboratory experiments with Fe-deficient <em>Raphidiopsis raciborskii</em>. Based on total P (TP) of lake water, we applied two doses of FeCl₃, corresponding to 30:1 (16 mg Fe L^-1) and 90:1 (47 mg Fe L^-1) (Fe:P molar), to cause P precipitation, and flocculation and sinking of cyanobacterial populations. Three enclosures per treatment and three without FeCl₃ additions (control) were used. The 90:1 treatment sank the main cyanobacterial biomass (50-fold) dominated by <em>Planktothrix agardhii</em>, with a significant decrease in turbidity, chlorophyll <em>a</em> and TP, without lasting decrease in pH, and achieved mesotrophic-like conditions. However, signs of recovery of <em>R. raciborskii</em> were detected between days 3 and 14. In laboratory experiments, Fe-deficient <em>R. raciborskii</em> MVCC19 grown under nitrate availability (+N) and N₂-fixation (–N) were exposed to five FeCl₃ concentrations from 0 to 17.9 (10:1) mg Fe L^-1 (Fe:P molar). A remarkable tolerance to high Fe was found at concentrations 7-fold higher than culture medium and decreased under –N. Also <em>R. raciborskii</em> stood low Fe levels in +N and exhibited higher Fe requirements under N₂-fixation. The increase in trichome length suggests resistance to the stressor, with shorter trichomes in –N. Therefore, effective management of <em>R. raciborskii</em> requires additional control of N in lakes. Our results point out the double role of Fe applications in which stress-tolerant species may become dominant under the reoligotrophication scenario.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"142 ","pages":"Article 102784"},"PeriodicalIF":5.5,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143144654","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":"Zooplankton grazing can facilitate and control the proliferation of harmful algal blooms caused by Dinophysis acuminata in NY, USA, estuaries","authors":"Megan Ladds,&nbsp;Christopher J. Gobler","doi":"10.1016/j.hal.2024.102789","DOIUrl":"10.1016/j.hal.2024.102789","url":null,"abstract":"<div><div>While harmful algal blooms (HABs) caused by the obligate-mixotroph, <em>Dinophysis acuminata</em>, have been associated with the ciliate, <em>Mesodinium rubrum,</em> the role of zooplankton grazing in the occurrence of these HABs has been under studied. Here, the dynamics of <em>D. acuminata</em> blooms were tracked within two NY, USA, harbors, over three years (2019–2021) during which grazing by native protozooplankton and introduced copepods (<em>Acartia tonsa</em>) was evaluated experimentally using an Imaging FlowCytobot (IFCB) to quantify plankton between 20 µm and 150µm. During each year, protoozooplankton grazing on <em>Dinophysis</em> was low during the bloom initiation period but exceeded cellular growth rates of <em>Dinophysis</em> during the peak bloom period, suggesting that a lack of grazing permitted bloom initiation but grazing onset facilitated bloom decline. The addition of juvenile <em>Acartia</em> increased <em>Dinophysis</em> growth rates in 10 of 14 experiments with differences being significant during three, bloom peak experiments. This finding suggests juvenile copepods can trigger a trophic cascade, potentially consuming <em>Dinophysis</em>-predators and releasing this HAB from grazer control. In contrast, adult <em>Acartia</em> and other mesozooplankton had minimal effects on <em>Dinophysis</em> densities suggesting that mesozooplankton did not directly impact blooms. Collectively, this study demonstrates that reduced grazing pressure at the onset of blooms facilitates bloom development, enhanced grazing during bloom peak can facilitate bloom decline, and that juvenile copepods can promote blooms via the induction of a trophic cascade.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"142 ","pages":"Article 102789"},"PeriodicalIF":5.5,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143379149","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":"Strain variability in toxin profiles and toxic potential of Dinophysis fortii populations from Southwestern and Northern Japanese coastal waters","authors":"Sirje Sildever ,&nbsp;Hajime Uchida ,&nbsp;Takanori Kuribayashi ,&nbsp;Masafumi Natsuike ,&nbsp;Yasufumi Hada ,&nbsp;Akira Miyazono ,&nbsp;Yuki Kosaka ,&nbsp;Natsuko Nakayama ,&nbsp;Wai Mun Lum ,&nbsp;Kazutaka Miyahara ,&nbsp;Kana Yamamoto ,&nbsp;Ryoji Matsushima ,&nbsp;Toshiyuki Suzuki ,&nbsp;Satoshi Nagai","doi":"10.1016/j.hal.2025.102803","DOIUrl":"10.1016/j.hal.2025.102803","url":null,"abstract":"<div><div>Harmful algal blooms are responsible for economic, societal, and health issues worldwide. In Japan, heterogeneity concerning diarrhetic shellfish poisoning (DSP) events has been reported, with most occurrences in the northern region. Although the toxin profile of <em>Dinophysis</em> cells from the DSP outbreaks has been investigated, no statistical comparison has been conducted on total toxin (particulate and released) production using cultured strains. A comparative toxin analysis was done based on &gt; 400 strains of <em>Dinophysis fortii</em> from Japan's southwestern and northern areas to investigate the heterogeneity in toxicity. Regardless of the origin, the toxin profile of all strains was dominated by PTX2. However, OA was the second most abundant toxin in the southwestern and DTX1 in the northern strains. For DTX1, the average concentrations in the north (330.54 ± 223.03 ng/mL) were significantly higher than in the southwest (5.85 ± 8.92 ng/mL). PTX2 also displayed significantly higher average concentrations in the north (384.51 ± 240.03 ng/mL) than in the southwest (122.66 ± 125.1 ng/mL). However, the northern strains had significantly lower levels of OA (6.74 ng/mL ± 13.53) than those from the southwest (34.86 ± 38.47 ng/mL). The total toxin yield in the northern strain cultures was about 56 times higher for DTX1, whereas OA content was 5 times lower, indicating significant differences in toxic potential in the strains from the two regions. The results of this toxin analysis contribute to the explanation of the geographical differences in DSP outbreaks associated with the blooms of <em>D. fortii</em> in Japan.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"142 ","pages":"Article 102803"},"PeriodicalIF":5.5,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143144165","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":"Unexpected shift from cyanobacterial to dinoflagellate dominance due to a summer drought","authors":"Sandra Rabow,&nbsp;Emma Johansson,&nbsp;Per Carlsson,&nbsp;Karin Rengefors","doi":"10.1016/j.hal.2024.102787","DOIUrl":"10.1016/j.hal.2024.102787","url":null,"abstract":"<div><div>The ruling paradigm is that future climate change scenarios will lead to an increase in the frequency, intensity, and duration of cyanobacterial blooms across the globe. It was therefore unexpected when, during an unusually warm and dry summer in southern Sweden in 2018, cyanobacteria did not dominate the phytoplankton community of the temperate Lake Vombsjön known for toxic cyanobacterial blooms. Instead, a potentially toxic dinoflagellate, <em>Naiadinium polonicum</em>, formed a large bloom and was dominant for the entire season. Dinoflagellates share important functional traits with cyanobacteria, but few studies have considered competition between dinoflagellates and cyanobacteria under future climate change scenarios. In order to understand the underlying factors leading to the <em>N. polonicum</em> bloom in 2018, we designed a study of Lake Vombsjön for an additional two years. When compared with subsequent years, 2018 was defined by an extended period of thermal stratification and hypoxia near the sediment surface. A significant positive relationship was also identified between <em>N. polonicum</em> biomass and both surface water temperature and soluble reactive phosphorus. We therefore suggest that the combination of higher temperatures and higher water column stability benefitted <em>N. polonicum</em> more so than cyanobacteria. Given that these factors are generally associated with cyanobacterial success, we conclude that freshwater phytoplankton community composition in temperate lakes can take different pathways in a warmer world.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"142 ","pages":"Article 102787"},"PeriodicalIF":5.5,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143144662","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":"Higher sensitivity of microcystin-producing Microcystis to two algaecides compared to co-cultured non-microcystin producers","authors":"Ying Wei ,&nbsp;Yunni Gao ,&nbsp;Jing Wu ,&nbsp;Jing Dong ,&nbsp;Jingxiao Zhang ,&nbsp;Xiaofei Gao ,&nbsp;Huatao Yuan ,&nbsp;Xuejun Li ,&nbsp;Michele A. Burford","doi":"10.1016/j.hal.2025.102798","DOIUrl":"10.1016/j.hal.2025.102798","url":null,"abstract":"<div><div>Targeting and selectivity are essential for assessing the effectiveness of ecofriendly algaecides in controlling toxic cyanobacterial blooms. The dose- and time-dependent effects of hydrogen peroxide (H₂O₂), pyrogallol and their sustained-release microcapsules (HRM, PRM) on proportion of MC-producing cell numbers and genotypes of the co-existing MC- and non-MC-producing <em>Microcystis</em>, as well as microcystins (MCs) concentrations were investigated in the present study. Two MC-producing and two non-MC-producing <em>Microcystis</em> strains were used in mono- and co-culture test systems. The findings revealed that the MC-producing <em>Microcystis</em> strains were more sensitive to both forms of H₂O₂ and pyrogallol in comparison with the non-MC-producing strains. Inhibition of all <em>Microcystis</em> strains by H₂O₂ and pyrogallol was found to be dose- and time-dependent, with H₂O₂ exhibiting stronger effects. Additionally, both pure and granular forms of H₂O₂ and pyrogallol reduced the relative abundance of MC-producing genotypes in co-culture conditions, along with total MC concentrations. The HRM and PRM demonstrated more potent and prolonged effects than their pure forms, indicating they are optimal for targeted reduction of <em>Microcystis</em> bloom toxicity. Their long-term effects against different levels of MC-producing <em>Microcystis</em> in various environmental conditions need further investigation through large-scale outdoor experiments.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"143 ","pages":"Article 102798"},"PeriodicalIF":5.5,"publicationDate":"2025-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143395513","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":"Clearance rates and toxin accumulation by North Atlantic bivalves during harmful algal blooms caused by the dinoflagellate, Dinophysis acuminata, in NY, USA, estuaries","authors":"Bradley T. McGuire ,&nbsp;Marta P. Sanderson ,&nbsp;Juliette L. Smith ,&nbsp;Christopher J. Gobler","doi":"10.1016/j.hal.2024.102745","DOIUrl":"10.1016/j.hal.2024.102745","url":null,"abstract":"<div><div>Diarrhetic shellfish poisoning (DSP) is the intoxication syndrome derived from the consumption of bivalves that have accumulated toxins produced by algae such as <em>Dinophysis acuminata</em>, yet no study has examined the rate at which bivalves feed on this toxigenic species. During 2021 and 2022, the clearance rates (CR) of three commercially significant bivalve species native to the western North Atlantic (<em>Crassostrea virginica, Mercenaria mercenaria</em>, and <em>Mytilus edulis</em>) were quantified during exposure to <em>D. acuminata</em> blooms of varying densities (10² – 10⁵ cells L⁻¹) at three sites across New York (NY), USA. The same bivalve species were deployed at NY sites experiencing <em>Dinophysis</em> blooms to track accumulation and depuration rates of diarrhetic shellfish toxins (DSTs) and pectenotoxins (PTXs), toxins that are harmful to humans or shellfish, respectively. A native, non-commercial mussel species (<em>Geukensis demissa</em>) was also sampled in situ to quantify toxin accumulation. CR of <em>D. acuminata</em> were greater than chlorophyll-<em>a</em>-based-rates for all bivalves and clearance rates of <em>D. acuminata</em> by <em>C. virginica</em> (1.69 ± 1.34 L h⁻¹ g⁻¹) were significantly greater than those of <em>M. edulis</em> (0.46 ± 0.32 L h⁻¹ g⁻¹) and <em>M. mercenaria</em> (0.41 ± 0.24 L h⁻¹ g⁻¹; <em>p</em> &lt; 0.05). During a bloom event in 2021, <em>C. virginica</em> and <em>M. mercenaria</em> accumulated low levels of pectenotoxin-2 (PTX2), whereas during a more sustained bloom in 2022, <em>C. virginica, M. edulis</em>, and <em>G. demissa</em> accumulated combinations of DSTs (okadaic acid (OA), dinophysistoxin-1 (DTX1)), PTX2, and pectenotoxin-2 seco acid (PTX2sa) with <em>M. edulis</em> DST loads (265 ng OA + DTX1 g⁻¹ shellfish tissue) exceeding the FDA closure guideline (160 ng toxin g⁻¹) for three weeks. DST concentrations in <em>M. edulis</em> were significantly higher (<em>p</em> &lt; 0.05) than <em>C. virginica</em> and <em>M. mercenaria</em>, whereas PTX2 concentrations in <em>C. virginica</em> were significantly higher than in all other bivalves (<em>p</em> &lt; 0.05). PTX2sa loads in <em>M. edulis</em> and <em>C. virginica</em> were similar to each other and were significantly greater than PTX2 loads (<em>p</em> &lt; 0.05). Toxin accumulation efficiencies (TAEs) were higher for <em>M. edulis</em> than <em>C. virginica,</em> and TAEs for DSTs were higher than for PTX2 and PTX2sa in both species. The combination of rapid CR of <em>D. acuminata</em> observed in all bivalves, even at &gt;10⁵ cells L⁻¹, and the ability of bivalves such as <em>M. edulis</em> to rapidly accumulate high levels of DSTs demonstrate these HABs may represent a significant DSP threat in North America.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"141 ","pages":"Article 102745"},"PeriodicalIF":5.5,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142793109","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}