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  • 1
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We investigated the impact of neurotoxins produced by the dinoflagellateAlexandrium excavatum on survival of Atlantic mackerel (Scomber scombrus) and American lobster (Homarus americanus) larvae, respectively reared from eggs and from female lobster, collected in 1988 from the southern Gulf of St. Lawrence, Canada. Sensitivity to the toxins was first verified by exposing larvae of both species to various concentrations of toxicA. excavatum (treatment) and non-toxicA. tamarense (control). Daily mortality rates ranged from 65 to 96% among mackerel larvae directly fed upon toxic cells and reached 36% in postlarvae exposed to toxic microzooplankton. Lobster larvae were apparently immune to the toxins, which they concentrated up to five times relative to vector toxicities. Bioassays conducted on mackerel larvae by exposure to natural plankton samples collected in situ during a bloom of toxicA. excavatum confirmed that exposure to the toxins could also have lethal effects in natural ecosystems. We conclude that the current proliferation of toxic dinoflagellates threatens early survival of finfish larvae and their recruitment to adult populations.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The planktonic copepod Calanus finmarchicus is a dominant member of the zooplankton community in the lower St. Lawrence Estuary in eastern Canada. Blooms of the toxic marine dinoflagellate Alexandrium excavatum which produces high cellular levels of paralytic shellfish poisoning (PSP) toxins, occur during the period of high C. finmarchicus production in summer in this region. To study the feeding behaviour of C. finmarchicus in the presence of Alexandrium spp., experiments were conducted in which female adult copepods collected from the St. Lawrence Estuary between May and September 1991 were exposed under controlled conditions to two toxic isolates of A. excavatum (Pr18b and Pr11f) from the estuary and to a non-toxic control (PLY 173) of a closely related species, A. tamarense isolated from the Tamar Estuary, Plymouth, U.K. Clearance rates on non-toxic A. tamarense cells averaged 5.5 ml ind-1 h-1 but were nearzero with either toxic isolate. When presented with a mixture of A. excavatum and the non-toxic diatom Thalassiosira weissflogii in varying proportions, C. finmarchicus fed upon the diatom but avoided the toxic dinoflagellate. Although feeding rates on A. excavatum were very low, toxin analysis by high-performance liquid chromatography with fluorescence detection (HPLC-FD) revealed that the PSP toxins were accumulated in copepods exposed to toxigenic dinoflagellates. The toxin composition in copepods was similar to that of the toxic dinoflagellate, but not necessarily identical, particularly after short-term (2-h) exposure, when relatively elevated levels of N-sulfocarbamoyl toxins were detected. The evidence suggests that C. finmarchicus ingests toxic dinoflagellate cells, either mistakenly or during exploratory bouts of feeding, and accumulates PSP toxins in its gut system and perhaps in other tissues.
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Marine biology 134 (1999), S. 541-549 
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Profiles of diarrhetic shellfish poisoning (DSP) toxins produced throughout the growth cycle and the cell cycle of the toxigenic marine dinoflagellate Prorocentrum lima were studied in triplicate unialgal batch cultures. Cells were pre-conditioned at 18 ± 1 °C, under a photon flux density (PFD) of 90 ± 5 μmol m−2 s−1 on a 14 h light:10 h dark photoperiod. In exponential growth phase, cultures were synchronized in darkness for 17 d. After dark synchronization, cultures were transferred back to the original photoperiod regime. Cells were harvested for DSP toxin analysis by LC-MS (liquid chromatography with mass spectrometry), and double-stranded (nuclear) DNA was quantified by flow cytometry. The cell populations became asynchronous within approximately 3 d after transition from darkness to the 14 h light:10 h dark photoperiod. This may be due to the prolonged division cycle (5 to 7 d) that is not tightly phased by the photoperiod. Unlike other planktonic Prorocentrum spp., cytokinesis in P. lima occurred early in the dark and ceased by “midnight”. Cellular levels of the four principal DSP toxins, okadaic acid (OA), OA C8-diol-ester (OA-D8), dinophysistoxin-1 (DTX1) and dinophysistoxin-4 (DTX4), ranged from 0.37 to 6.6, 0.02 to 1.5, 0.04 to 2.6, and 1.8 to 7.8 fmol cell−1, respectively. No toxin production was evident during the extended period of dark synchronization nor during the initial period when NH4 was consumed as the major nitrogen source. Soon after the cells were returned to the 14 h light:10 h dark cycle and they began to take up NO3, cellular levels of all four toxins gradually increased. This increase in DSP toxins usually occurred in the light, marked by a rise in DTX4 levels that preceded an increase in the cellular concentration of OA and DTX1 (delayed by 3 to 6 h). Thus, DTX4 synthesis is initiated in the G1 phase of the cell cycle and persists into S phase (“morning” of the photoperiod), whereas OA and DTX1 production occurs later during S and G2 phases (“afternoon”). No toxin production was measured during cytokinesis, which happened early in the dark. The evidence indicates that toxin synthesis is restricted to the light period and is coupled to cell cycle events.
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  • 4
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Procedures have been developed for the extraction and high-performance liquid chromatography (HPLC) analysis of paralytic shellfish poisoning (PSP) toxins from Protogonyaulax spp. grown in batch culture. Using these procedures, the toxin content of two isolates of P. tamarensis (NEPCC 183 and 255) and one isolate of P. catenella (NEPCC 355) were examined. Total toxin and individual toxin concentrations were measured for each isolate during the exponential and stationary phases of growth in batch culture. The total toxicity of each isolate as measured by HPLC analysis was found to agree with toxicity as determined by the standard mouse bioassay. Two of the isolates (255 and 355) were found to be toxic and the third (183) was non-toxic. The toxic isolates (255 and 355) both showed higher average total PSP toxin content during the exponential phase (35 and 23 fmol toxin cell-1, respectively) than during the stationary phase (21 and 8 fmol toxin cell-1, respectively). These cultures differed dramatically in their toxin composition. P. tamarensis (255) contained a large proportion of the N(21) sulfo toxins (B1, B2, C1, C2) while P. catenella (355) contained primarily Gonyautoxins 1 through 4. The percent composition of individual toxins was found to be constant throughout the growth cycle for both toxic isolates, even though the total toxin concentration varied. Our results suggest that PSP toxin profiles might be useful as chemotaxonomic indicators.
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  • 5
    ISSN: 0951-4198
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: A combined liquid chromatography/mass spectrometry (LC/MS) method using ion-spray ionization is described for the sensitive determination of okadaic acid and dinophysistoxin-1, the principal toxins implicated in cases of diarrhetic shellfish poisoning. The method is used to confirm the presence of okadaic acid in a culture of the dinoflagellate species Prorocentrum concavum and in natural populations of dinoflagellates from eastern Canadian waters. Several analogues of the toxin have also been detected. Quantitative results are comparable to those obtained by high performance liquid chromatography with fluorescence detection. With slight modifications, the LC/MS method is also used to analyse the fluorescent anthrylmethyl ester of okadaic acid. Preliminary tandem mass spectrometric results, obtained using fast-atom bombardment ionization, are presented for okadaic acid.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1573-5176
    Keywords: dinoflagellate ; diarrheic shellfish poisoning ; okadaic acid ; Dinophysis ; Phalacroma
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Okadaic acid, one of the principal toxin components implicated in cases of diarrheic shellfish poisoning (DSP), was identified for the first time in natural phytoplankton assemblages from North American waters. During periods in late summer when significant quantities of okadaic acid were detected in net haul samples in the lower estuary and Gulf of St Lawrence in eastern Canada, the phytoplankton community consistently contained species of the dinoflagellate genusDinophysis Ehrenberg. The presence of okadaic acid was detected by screening dinoflagellate extracts with an enzyme-linked immunological assay (ELISA); positive results were confirmed by reverse-phase high-performance liquid chromatography (HPLC) separation, followed by fluorescence detection. Okadaic acid was only found in phytoplankton samples in which the photosynthetic dinophysoid speciesD. norvegica andD. acuminata were prominent; blooms of the related heterotrophic speciesD. rotundata exhibited no trace of okadaic acid, nor other suspected DSP components.
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  • 7
    Publication Date: 2012-12-28
    Description: Molecular probes were developed for the dinoflagellate genus Azadinium to discriminate among three taxa difficult to differentiate by light microscopy. This genus contains azaspiracid toxin-producing Azadinium spinosum , but also non-toxigenic species. Quantitative polymerase chain reaction (qPCR) and fluorescence in situ hybridization (FISH) assays were applied to cultured isolates and Azadinium -spiked field plankton. Molecular methods were highly specific and sensitive in the unambiguous detection of Azadinium , and thus are valuable for routine plankton, biogeographic and phylogenetic investigations.
    Print ISSN: 0142-7873
    Electronic ISSN: 1464-3774
    Topics: Biology
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  • 8
    Publication Date: 2013-08-28
    Description: From the German Bight along Jutland to the western Skagerrak, we found representatives of almost all groups of phycotoxins known to occur in North Sea plankton. Identification was by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) in plankton size fractions, with domoic acid and 20-me G the most abundant toxins. The dominance of 20-me G in the spirolide (SPX) composition of plankton from the Jutland current system matched very well with that of an isolate of the dinoflagellate Alexandrium ostenfeldii . The SPXs of the A. ostenfeldii strain S6_P12_E11, previously isolated from the western North Sea along the Scottish coast, comprised 100% 20-me G, suggesting toxin homogeneity among North Sea populations of this species. We detected highest amounts of azaspiracid-1 in the 3–20-µm size fraction at offshore stations, where the Jutland coastal current converges with the westward North Sea flow off Skagerrak. Azadinium spinosum was subsequently identified by clonal isolation from crude cultures established from these stations. Except for lipophilic toxins usually produced by the dinoflagellate Dinophysis spp., dinophysistoxin-1 (DTX-1) and DTX-2, we detected no other phycotoxins in plankton from the southern German Bight. The spatial distribution of the phycotoxins in the eastern North Sea was apparently related to the hydrographical conditions, identified from salinity and coloured dissolved organic matter profiles. The biogeographical distribution of phycotoxins indicates a strong association with the northward advection by the Jutland current and the mixing of German Bight and North water masses along the northwest Danish coast towards the Skagerrak.
    Print ISSN: 0142-7873
    Electronic ISSN: 1464-3774
    Topics: Biology
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  • 9
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    Intergovernmental Oceanographic Commission and Scientific Committee on Oceanic Research OC and SCOR, Paris, France and Newark, Delaware USA, 52 pp.
    In:  EPIC3Second Open Science Meeting. Progress in Interpreting Life History and Growth Dynamics of Harmful Algal Blooms in Fjords and Coastal Environments., Intergovernmental Oceanographic Commission and Scientific Committee on Oceanic Research OC and SCOR, Paris, France and Newark, Delaware USA, 52 pp., GEOHAB(10), 52 p.
    Publication Date: 2019-07-17
    Description: As part of the activities of the Global Ecology and Oceanography of Harmful Algal Blooms (GEOHAB)programme, Open Science Meetings (OSMs) have been organized to discuss and synthesize research efforts on various aspects of harmful algal blooms (HABs), and to plan future collaborative activities relevant to the research theme. Within this framework, the steering committee of the GEOHAB Core Research Project on HABs in Fjords and Coastal Embayments has organized two OSMs. The first OSM was held in 2004 in Santiago, Chile; the major goals were to identify the primary research priorities and to initiate an agenda to further our understanding of HAB dynamics in these small-scale coastal systems. The second OSM was held in May 2012 in Victoria,Canada to highlight the progress accomplished since the first OSM and to focus attention on the importance of a comparative approach in conducting ecosystem studies to improve our understanding of HABs. This second OSM addressed four major themes for which significant advances have been made in recent years, with particular focus on their application to semi-enclosed basins linked to coastal ecosystems: (1) Life history of HAB species; (2) Chemical ecological and toxin interactions; (3) Genetic diversity and (4) Transport and mixing of blooms in small-scale, mesoscale and semi-confined systems. This Report presents the major outcomes of this OSM, followed by recommendations for future collaborative studies. These recommendations include the maintenance of international activities on the ecology and oceanography of HABs after the end of the GEOHAB programme in December 2013. A future agenda should focus on a few key questions with clearly identifiable deliverables. These questions should include the development of (i) improved methods to determine the rates of cyst formation and germination in the field, and (ii) coupled biological-physical-chemical models more appropriate to small-scale environments and which incorporate the role of allelochemicals and toxins, as well as the pelagic and benthic coupling components. Research devoted to life history stages should be continued, particularly with respect to fish-killing algal species that cause particular damage in coastal environments. The influence of aquaculture activities on the development of HABs is poorly understood and should be of greater concern in future research on HABs. The influence of climate change, which may be exacerbated in coastal environments, also should be a focus of future research. Long-term ecological research should be encouraged in this respect, in order to make better predictions in the future concerning the development of HABs in coastal environments.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Miscellaneous , notRev
    Format: application/pdf
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  • 10
    Publication Date: 2022-09-21
    Description: • Harmful Algal Blooms (HABs) result from noxious and/or toxic algae that cause direct and indirect negative impacts to aquatic ecosystems, coastal resources, and human health. • HABs are present in nearly all aquatic environments (freshwater, brackish and marine), as naturally occurring phenomena. • Many HABs are increasing in severity and frequency, and biogeographical range. Causes are complex, but in some cases can be attributed to climate change and human impacts, including eutrophication, habitat modification, and human- mediated introduction of exogenous species. • There is no plan, and nor realistic possibility, to eliminate HABs and/or their depend-ent consequences. Decades of research and monitoring have, however, improved our understanding of HAB events, leading to better monitoring and prediction strate-gies. • HABs are a worldwide phenomenon requiring an international understanding leading ultimately to local and regional solutions. Continued progress in research, management, mitigation, and prediction of HABs benefits from international coordination. In this spirit, the international community has developed programmes sponsored by the Intergovernmental Oceanographic Commission (IOC) and Scientific Committee on Oceanic Research (SCOR) to coordinate international HAB research, framework activities, and capacity building. • HABs are recognized as one facet of complex ecosystem interactions with human society. HAB research, monitoring, and management must be closely integrated with policy decisions that affect our global oceans. • New initiatives, such as GlobalHAB sponsored by IOC and SCOR, will continue to provide the mechanisms to further understand, predict, and mitigate HABs. Research, management, and mitigation efforts directed towards HABs must be coordinated with other local, national, and international efforts focused on food and water security, human and ecosystem health, ocean observing systems, and climate change.
    Description: OPENASFA INPUT For bibliographic purposes this document should be cited as: R.M. Kudela et al. 2015. Harmful Algal Blooms. A Scientific Summary for Policy Makers. IOC/UNESCO, Paris (IOC/INF-1320).
    Description: Published
    Description: Non Refereed
    Keywords: HAB ; Harmful Algae Bloom ; Noxious algae ; Toxic algae ; Aquatic ecosystems ; Coastal resources ; Human health ; Climate Change ; Human impact ; Policy making ; Food security ; Water security
    Repository Name: AquaDocs
    Type: Report
    Format: 20pp.
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