Harmful AlgaePub Date : 2024-11-26DOI: 10.1016/j.hal.2024.102769
Suh Nih Tan , Yuichi Kotaki , Sing Tung Teng , Hong Chang Lim , Chunlei Gao , Nina Lundholm , Matthias Wolf , Haifeng Gu , Po Teen Lim , Chui Pin Leaw
{"title":"Intraspecific genetic diversity with unrestricted gene flow in the domoic acid-producing diatom Nitzschia navis-varingica (Bacillariophyceae) from the Western Pacific","authors":"Suh Nih Tan , Yuichi Kotaki , Sing Tung Teng , Hong Chang Lim , Chunlei Gao , Nina Lundholm , Matthias Wolf , Haifeng Gu , Po Teen Lim , Chui Pin Leaw","doi":"10.1016/j.hal.2024.102769","DOIUrl":"10.1016/j.hal.2024.102769","url":null,"abstract":"<div><div>The benthic pennate diatom <em>Nitzschia navis</em>-<em>varingica</em>, known for producing domoic acid (DA) and its isomers, is widely distributed in the Western Pacific (WP) region. To investigate the genetic differentiation and gene flow patterns among the populations in the WP, the genetic diversity of 354 strains of <em>N. navis-varingica</em> was analysed using two nuclear-encoded rDNA loci: the large subunit rDNA (LSU rDNA) and the internal transcribed spacer 2 (ITS2). Frustule morphology of each strain was examined by TEM. The LSU rDNA phylogeny revealed a monophyletic lineage encompassing all strains, with sequence divergences of <0.9 %. Phylogenetic and population genetic analyses of ITS2 identified eight distinct clades (designated as Groups A to H) with moderate to high genetic heterogeneity (0.5–19.7 %). The low genetic differentiations between the geographically separated populations (pairwise <em>F<sub>ST</sub></em> of <0.03) suggested high gene flow and lack of spatial genetic structuring. Molecular clock analysis of the ITS2 phylogeny traced the evolutionary history of <em>N. navis-varingica</em> to the Eocene Epoch, and the split between clades likely occurred from the mid-Miocene to Pleistocene Epochs (10.8–1.2 Ma). The population dispersal in the WP were likely influenced by historical events like the Quarternary glacial cycles during the period, contributing to its homogenous distributions in the region.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"141 ","pages":"Article 102769"},"PeriodicalIF":5.5,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142745986","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}
Harmful AlgaePub Date : 2024-11-23DOI: 10.1016/j.hal.2024.102768
Dani Glidewell, Jessica E. Beyer, K. David Hambright
{"title":"Microcystins bioaccumulate but do not biomagnify in an experimental aquatic food chain","authors":"Dani Glidewell, Jessica E. Beyer, K. David Hambright","doi":"10.1016/j.hal.2024.102768","DOIUrl":"10.1016/j.hal.2024.102768","url":null,"abstract":"<div><div>Microcystins—common hepatotoxins produced by cyanobacteria—have been detected in a wide range of organisms, though research examining the trophic transfer of microcystins and whether microcystins bioaccumulate or biomagnify in food webs has generated contradictory results. Here, we explored the trophic transfer of microcystins from the herbivorous water flea, <em>Daphnia pulex</em>, to the predatory larvae of a damselfly, <em>Enallagma</em> sp. We tested the hypotheses that microcystins transfer from the tissue of herbivorus zooplankton to that of predatory invertebrates and that these toxins biomagnify across trophic levels. We also assessed the relative contribution of toxin transfer from the gut and tissue of <em>Daphnia pulex</em> to <em>Enallagma</em> sp. We found that microcystins are effectively sequestered in the tissue of <em>Daphnia pulex</em>, and that these sequestered toxins are then transferred to the tissue of <em>Enallagma</em> sp. The contribution of gut contents to toxin transfer was negligible. Contrary to the pattern predicted by biomagnification, we found that the concentration of microcystins decreased with increasing trophic levels. Our results support the hypothesis that microcystins can be transferred trophically, but do not support the hypothesis that microcystins biomagnify from lower to higher trophic levels. Conversly, we observe biodilution in this system. These results have consequences for the impact of microcystins across trophic levels in a changing world with increasing intensity and duration of harmful algal blooms.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"141 ","pages":"Article 102768"},"PeriodicalIF":5.5,"publicationDate":"2024-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142746092","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}
Harmful AlgaePub Date : 2024-11-23DOI: 10.1016/j.hal.2024.102761
Shuning Huang , Kenneth Neil Mertens , Amélie Derrien , Ophélie David , Hyeon Ho Shin , Zhun Li , Xiuyun Cao , Marina Cabrini , Daniela Klisarova , Haifeng Gu
{"title":"Gonyaulax montresoriae sp. nov. (Dinophyceae) from the Adriatic Sea produces predominantly yessotoxin","authors":"Shuning Huang , Kenneth Neil Mertens , Amélie Derrien , Ophélie David , Hyeon Ho Shin , Zhun Li , Xiuyun Cao , Marina Cabrini , Daniela Klisarova , Haifeng Gu","doi":"10.1016/j.hal.2024.102761","DOIUrl":"10.1016/j.hal.2024.102761","url":null,"abstract":"<div><div>Yessotoxin is one of the shellfish toxins leading to mussel farm closures in the Adriatic Sea of Italy. Two putative <em>Gonyaulax spinifera</em> strains GSA0501 and GSA0602 are known as yessotoxins producers, but their identities have remained elusive since 2005. To address this gap, we established five <em>Gonyaulax</em> strains by incubating sediments from the Adriatic Sea and subsequently isolating single cells. Both cyst and theca morphology were examined using light and scanning electron microscopy. In addition, LSU and/or SSU rRNA gene sequences were obtained for all strains. Two strains produce cysts resembling <em>Spiniferites mirabilis</em> and one strain was related to <em>S. scabratus.</em> The other two strains are described as <em>Gonyaulax montresoriae</em> sp. nov., characterized by a high cingular displacement and overhang, along with two unequal antapical spines. Cysts of <em>G. montresoriae</em> are pear-shaped, showing a smooth surface and exclusively gonal processes with perforations at the base, the latter similar to <em>S. lazus</em>. LSU rRNA gene sequence comparison suggests that the <em>G. spinifera</em> strain GSA0501 isolated from the Adriatic Sea in 2005 should also be identified as <em>G. montresoriae.</em> Maximum likelihood and Bayesian inference analyses based on LSU and SSU rRNA gene sequences reveal that <em>G. montresoriae</em> is monophyletic, and close to several toxic strains of presumable <em>Gonyaulax spinifera</em> from the Adriatic Sea and New Zealand, whose taxonomic positions are uncertain. One strain of <em>G. montresoriae</em> was examined for yessotoxin production using LC-MS/MS, and found to produce predominantly yessotoxin at a concentration of 3.0 pg cell<sup>-1</sup>. Our results highlight the rich diversity and risks associated with <em>Gonyaulax</em> species in the Mediterranean Sea.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"141 ","pages":"Article 102761"},"PeriodicalIF":5.5,"publicationDate":"2024-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142721836","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}
Harmful AlgaePub Date : 2024-11-18DOI: 10.1016/j.hal.2024.102760
Wenhui Yan , Guixiang Wang , Ying Ji , Jiangbing Qiu , Chengxu Zhou , Aifeng Li
{"title":"Influence of nitrate and salinity on growth and toxin production of Prymnesium parvum","authors":"Wenhui Yan , Guixiang Wang , Ying Ji , Jiangbing Qiu , Chengxu Zhou , Aifeng Li","doi":"10.1016/j.hal.2024.102760","DOIUrl":"10.1016/j.hal.2024.102760","url":null,"abstract":"<div><div>Fish-killing events caused by haptophyte <em>Prymnesium parvum</em> have been reported in aquatic environments worldwide. This haptophyte could produce diverse prymnesins (PRMs) that harm to aquatic organisms like fishes. In this study, the components of prymnesins in the strain of <em>P. parvum</em> (NMBjih029) isolated from the coast of Ningbo city, China, were elucidated by a high-resolution mass spectrometer (HRMS), and the influence of nitrate levels and salinity on growth and toxin production of <em>P. parvum</em> were also explored. Results showed that the <em>P. parvum</em> produced C-type prymnesins with structure variations in saturation, chlorination, and sugar modifications. The growth and toxin production were significantly affected by nitrate levels in the batch cultures. At the lowest level of nitrate (N:P = 4:1), growth of <em>P. parvum</em> was inhibited but toxin quotas per cell increased up to approximately 4 times of that in control group (N:P = 16:1) during the exponential growth stage. Growth of <em>P. parvum</em> was not obviously affected by different salinities, but the biosynthesis of prymnesins increased with decreasing salinity from 32 to 14 in the culture media. The proportion of high chlorination of prymnesins (tetrachloride) increased in <em>P. parvum</em> under nitrogen limitation stress and low salinity. And the toxin quotas per cell also markedly increased with the extension of culture period in <em>P. parvum</em> under nitrogen limitation and different salinity conditions. This study provides some important cues for toxin profile and environmental impacts on the biosynthesis of prymnesins in the strain of <em>P. parvum</em> isolated from Chinese aquatic environments.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"140 ","pages":"Article 102760"},"PeriodicalIF":5.5,"publicationDate":"2024-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142700429","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}
Harmful AlgaePub Date : 2024-11-15DOI: 10.1016/j.hal.2024.102746
Zhe Tao , Xiaohan Liu , Xiaoying Song , Yunyan Deng , Lixia Shang , Zhaoyang Chai , Zhangxi Hu , Yuyang Liu , Ying Zhong Tang
{"title":"Species and genetic diversity of notorious dinoflagellates Pfiesteria piscicida, Luciella masanensis, and relatives in marine sediments of China","authors":"Zhe Tao , Xiaohan Liu , Xiaoying Song , Yunyan Deng , Lixia Shang , Zhaoyang Chai , Zhangxi Hu , Yuyang Liu , Ying Zhong Tang","doi":"10.1016/j.hal.2024.102746","DOIUrl":"10.1016/j.hal.2024.102746","url":null,"abstract":"<div><div>The dinoflagellate genus <em>Pfiesteria</em>, encompassing <em>Pfiesteria piscicida</em> and <em>P. shumwayae</em>, became a hot topic in HABs research in the early 2000s due to numerous but controversial reports regarding life cycle and toxicity. While <em>Pfiesteria</em> presence has been reported from all continents, surprisingly, there has been no documented presence in China to date. Here, we report our findings on the presence, species, and genetic diversity of <em>Pfiesteria</em> and its phylogenetic relatives (particularly <em>Luciella masanensis</em>) using a combined approach. First, we demonstrated the presence of <em>P. piscicida</em> and <em>L. masanensis</em> using metabarcoding analysis of >320 sediment samples. <em>Pfiesteria piscicida</em> was identified in 32 sampling sites across all four seas of China, with rDNA sequences exhibiting considerable differences from the type strain (up to 3.83 %), while <em>Luciella masanensis</em> presented in 212 sites from all four seas and included only ribotypes 1 and 3 among the four known ribotypes. Second, based on the metabarcoding detections, our application of FISH with species-specific probes and subsequent single-cyst PCR sequencing to the “positive” sediments confirmed, both morphologically and molecularly, the existence of <em>P. piscicida</em> and <em>L. masanensis</em> cysts in the sediments. Finally, individual cysts were isolated using the sodium polytungstate protocol and sequenced targeting 28S rDNA D1–D6 domains. Phylogenetic analysis revealed that 35 resting cysts were relatives of <em>Pfiesteria</em>, likely belonging to either new species or novel genera and family because they formed at least two distinct clades in the phylogenetic tree. <em>Pfiesteria shumwayae</em> was not detected from any sample, suggesting its absence in Chinese waters. We believe this work provides important factual basis for the global biogeography of these species and future HABs monitoring of in China.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"140 ","pages":"Article 102746"},"PeriodicalIF":5.5,"publicationDate":"2024-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142661258","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}
Harmful AlgaePub Date : 2024-11-10DOI: 10.1016/j.hal.2024.102757
Brittany N. Zepernick , Lauren N. Hart , Emily E. Chase , Kaela E. Natwora , Julia A. Obuya , Mark Olokotum , Katelyn A. Houghton , E. Anders Kiledal
{"title":"Molecular investigation of harmful cyanobacteria reveals hidden risks and niche partitioning in Kenyan Lakes","authors":"Brittany N. Zepernick , Lauren N. Hart , Emily E. Chase , Kaela E. Natwora , Julia A. Obuya , Mark Olokotum , Katelyn A. Houghton , E. Anders Kiledal","doi":"10.1016/j.hal.2024.102757","DOIUrl":"10.1016/j.hal.2024.102757","url":null,"abstract":"<div><div>Despite the global expansion of cyanobacterial harmful algal blooms (cHABs), research is biased to temperate systems within the global north, such as the Laurentian Great Lakes. This lack of diversity represents a significant gap in the field and jeopardizes the health of those who reside along at-risk watersheds in the global south. The African Great Lake, Lake Victoria, is understudied despite serving as the second largest lake by surface area and demonstrating year-round cHABs. Here, we address this knowledge gap by performing a molecular survey of cHAB communities in three anthropogenically and ecologically important freshwater systems of Victoria's Kenyan watershed: Winam Gulf (Lake Victoria), Lake Simbi and Lake Naivasha. We identified a bloom of non-toxic <em>Dolichospermum</em> and toxic <em>Microcystis</em> in the Winam Gulf, with data suggesting sulfur limitation shapes competition dynamics between these two bloom-formers. Though we did not detect a bloom in Naivasha, it contained the largest diversity of cHAB genera amongst the three lakes. In turn, our results indicated methane metabolism may allow non-toxic picoplankton to outcompete cHAB genera, while suggesting <em>Synechococcus</em> spp. serves as a methane source and sink in this system. Lake Simbi exhibited a non-toxic <em>Limnospira</em> bloom at the time of sampling with very low abundances of cHAB genera present. Subsequently, these results were employed to design a cHAB screening and risk assessment framework for local stakeholders. Cumulatively, this work serves to increase cHAB research efforts on the international scale while serving as an impetus for cHAB monitoring on the local scale.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"140 ","pages":"Article 102757"},"PeriodicalIF":5.5,"publicationDate":"2024-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142661259","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}
Harmful AlgaePub Date : 2024-11-09DOI: 10.1016/j.hal.2024.102756
Simon Tulatz , Bernd Krock , Urban Tillmann , Cédric Leo Meunier
{"title":"Effects of temperature, salinity and CO2 concentration on growth and toxin production of the harmful algal bloom species Alexandrium pseudogonyaulax (Dinophyceae) from the Danish Limfjord","authors":"Simon Tulatz , Bernd Krock , Urban Tillmann , Cédric Leo Meunier","doi":"10.1016/j.hal.2024.102756","DOIUrl":"10.1016/j.hal.2024.102756","url":null,"abstract":"<div><div>The marine dinoflagellate <em>Alexandrium pseudogonyaulax</em> is a widely distributed Harmful Algal Bloom (HAB) species that produces the macrocyclic polyketide goniodomin A (GDA). Occurrences in northern European waters are increasing and a spreading of the species along a salinity gradient into the Baltic Sea has been observed. As GDA is suspected to lead to invertebrate mortality, the spreading is of concern for the environment and possibly human health. In order to assess the potential of <em>A. pseudogonyaulax</em> to adapt to the environmental conditions in the Baltic Sea and the risk of future harmful blooms of that species, we quantified the influence of bottom-up factors on the growth and toxin content of three strains of <em>A. pseudogonyaulax</em> from the Danish Limfjord. Specifically, we exposed these strains to salinities ranging from 5 to 50, temperatures in the range of 10 – 30 °C and to three different CO<sub>2</sub> concentrations of 250, 400 and 1000 µatm. All strains tolerated a broad range of salinities and temperatures, resulting in positive growth rates ranging from 0.06 to 0.33 d<sup>-1</sup> between temperatures of 12 and 27 °C and between salinities of 10 and 40. The highest cell quotas of GDA were measured at low temperatures. For two strains, GDA amounts were almost unaffected by salinity, while the cell quota of the third strain decreased about 20-fold when salinity increased above 30. Different CO<sub>2</sub> concentrations had no effect on growth or GDA production. In summary, these findings show a high ecological tolerance towards a wide range of temperatures and salinities of the Limfjord population of <em>A. pseudogonyaulax</em>, together with distinct intraspecific physiological differences within the population. Our results also suggest that a further spreading into the Baltic Sea might be possible.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"140 ","pages":"Article 102756"},"PeriodicalIF":5.5,"publicationDate":"2024-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142661267","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}
Harmful AlgaePub Date : 2024-11-09DOI: 10.1016/j.hal.2024.102747
Emily Pierce , Marco Valera , Mark Vander Borgh , Daniel Wiltsie , Elizabeth Fensin , Charlton Godwin , Jill Paxson , Gloria Putnam , Colleen Karl , Blake Schaeffer , Astrid Schnetzer
{"title":"Unprecedented toxic blooms of Microcystis spp. in 2019 in the Chowan River, North Carolina","authors":"Emily Pierce , Marco Valera , Mark Vander Borgh , Daniel Wiltsie , Elizabeth Fensin , Charlton Godwin , Jill Paxson , Gloria Putnam , Colleen Karl , Blake Schaeffer , Astrid Schnetzer","doi":"10.1016/j.hal.2024.102747","DOIUrl":"10.1016/j.hal.2024.102747","url":null,"abstract":"<div><div>The Chowan River flows from southern Virginia through northeastern North Carolina and into the Albemarle Sound, a part of the second largest U.S. estuary. The Chowan, which serves as an important recreational area and provides critical nursery habitat for multiple vulnerable species, has garnered much attention in recent years due to recurrent cyanobacterial harmful algal blooms (cHABs) associated with microcystins (MCs). Here we document unprecedented toxic blooms of <em>Microcystis</em> spp. during summer and fall of 2019 with MC concentrations two to three orders above the recreational guidelines of the Environmental Protection Agency (EPA, 2019). Based on 16S sequencing results in this study and previously published reports, the genus <em>Microcystis</em> emerged as a primary concern within the region. Shifts in assemblage composition, including relative abundance of <em>Microcystis</em> spp. and contributions from potential MC-degraders, linked to overall toxin concentrations and bloom stage. Congeners of varying toxicity, mainly MC-RR and MC-LR, were the most prevalent, corroborating that congeners other than MC-LR should be considered as health risk guidelines are developed. Downstream toxin transport was indicated based on changes in accumulated dissolved MC within the western Albemarle Sound which matched toxin dynamics in the Chowan River. This study provides important novel data on bacterial community composition, MC dynamics, and spatial connectivity for the Chowan River region that can aid monitoring approaches and management strategies for the protection of public health along the Chowan River and within the western Albemarle Sound.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"140 ","pages":"Article 102747"},"PeriodicalIF":5.5,"publicationDate":"2024-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142700354","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}
Harmful AlgaePub Date : 2024-11-07DOI: 10.1016/j.hal.2024.102743
Rocio I. Ruiz-Cooley , Clarissa Anderson , Raphael Kudela , Robin Dunkin , John Field
{"title":"Perturbations in a pelagic food web during the NE pacific large marine heatwave and persistent harmful diatom blooms","authors":"Rocio I. Ruiz-Cooley , Clarissa Anderson , Raphael Kudela , Robin Dunkin , John Field","doi":"10.1016/j.hal.2024.102743","DOIUrl":"10.1016/j.hal.2024.102743","url":null,"abstract":"<div><div>Unprecedented warm ocean conditions, driven by the Large Marine Heatwave (LMH) and the 2015–16 El Niño in the Northeast Pacific favored pervasive toxigenic <em>Pseudo-nitzschia</em> spp. blooms that caused widespread ecological impacts, but little is known about the magnitude to which marine food webs were altered. Here, we assessed the trophic transfer of domoic acid (DA; a neurotoxin) and changes in trophic position from multiple key species during the peak of the LMH and El Niño in 2015 in comparison with 2018, a reference non-anomalous warm year. DA and amino acid nitrogen isotopes (δ<sup>15</sup>N <sub>AAs</sub>) were quantified using liquid and gas chromatography mass spectrometry, respectively. Our integrative approach revealed extremely high levels of DA in anchovy viscera (>3000 μg/g) with contrasting baseline values (δ<sup>15</sup>N <sub>Phe</sub>) for southern California fish. These results together with data from northern CA revealed an unforeseen latitudinal isotopic variation in key DA vectors along California, possibly driven by anomalous restructuring of water masses. At the regional level, the observed cross-shore differences in baseline isotope values and DA toxicity suggest distinct pathways for DA trophic transfer for nearshore vs. offshore sites. Given the high levels of environmental disturbance during the LMH and persistence of toxigenic <em>P. australis</em> blooms, our resultant higher trophic position proxies in 2015 compared to 2018 were particularly unexpected. Such results highlight complex trophic interactions, where the trophic status of some species increased while others decreased in response to changes in net primary productivity, and biodiversity, and abundance of forage species. Our study demonstrates the use of δ<sup>15</sup>N AAs to identify pathways of N and DA trophic transfer and to quantify shifts in animal trophic position, a critical facet of understanding the response of food webs to climate change and DA production.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"140 ","pages":"Article 102743"},"PeriodicalIF":5.5,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142700353","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}