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  • 1
    Publikationsdatum: 2019-07-16
    Beschreibung: The Alexandrium tamarense species complex is one of the most studied marine dinoflagellate groups due to its ecological, toxicological and economic importance. Several members of this complex produce saxitoxin and its congeners - potent neurotoxins that cause paralytic shellfish poisoning. Isolates from this complex are assigned to A. tamarense, A. fundyense, or A. catenella based on two main morphological characters: the ability to form chains and the presence/absence of a ventral pore between Plates 1′ and 4′. However, studies have shown that these characters are not consistent and/or distinctive. Further, phylogenies based on multiple regions in the rDNA operon indicate that the sequences from morphologically indistinguishable isolates partition into five clades. These clades were initially named based on their presumed geographic distribution, but recently were renamed as Groups I-V following the discovery of sympatry among some groups. In this study we present data on morphology, ITS/5.8S genetic distances, ITS2 compensatory base changes, mating incompatibilities, toxicity, the sxtA toxin synthesis gene, and rDNA phylogenies. All results were consistent with each group representing a distinct cryptic species. Accordingly, the groups were assigned species names as follows: Group I, A. fundyense; Group II, A. mediterraneum; Group III, A. tamarense; Group IV, A. pacificum; Group V, A. australiense.
    Repository-Name: EPIC Alfred Wegener Institut
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  • 2
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    Annual Reviews
    In:  EPIC3Annu. Rev. Mar. Sci., Annual Reviews, 4, pp. 143-176
    Publikationsdatum: 2019-07-17
    Beschreibung: The public health, tourism, fisheries, and ecosystem impacts from harmful algal blooms (HABs) have all increased over the past few decades. This has led to heightened scientific and regulatory attention, and the development of many new technologies and approaches for research and management. This, in turn, is leading to significant paradigm shifts with regard to, e.g.,our interpretation of the phytoplankton species concept (strain variation), the dogma of their apparent cosmopolitanism, the role of bacteria and zooplankton grazing in HABs, and our approaches to investigating the ecological and genetic basis for the production of toxins and allelochemicals. Increasingly,eutrophication and climate change are viewed andmanaged as multifactorial environmental stressors that will further challenge managers of coastal resources and those responsible for protecting human health. Here we review HABscience with an eye toward new concepts and approaches,emphasizing, where possible, the unexpected yet promising new directions that research has taken in this diverse field.
    Repository-Name: EPIC Alfred Wegener Institut
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  • 3
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    International Association for Plant Taxonomy
    In:  EPIC3Taxon, International Association for Plant Taxonomy, 63(4), pp. 932-933, ISSN: 0040-0262
    Publikationsdatum: 2014-10-07
    Repository-Name: EPIC Alfred Wegener Institut
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  • 4
    Publikationsdatum: 2022-05-25
    Beschreibung: Author Posting. © Oceanography Society, 2010. This article is posted here by permission of Oceanography Society for personal use, not for redistribution. The definitive version was published in Oceanography 23, no. 3 (2010): 72-85.
    Beschreibung: Harmful algal blooms (HABs) have become an important subdiscipline within oceanography. Heightened attention to this topic as well as significant research advances reflect the global nature of the problem and the development of strong national and international programs for HAB research and management. The planning, communication, coordination, and capacity-building activities of the Intergovernmental Oceanographic Commission (IOC) have been a key factor in this growth. Here, we highlight selected advances in science and management capacity for HABs and document the impressive growth of the field in the context of activities supported directly or indirectly by IOC. As we look to the future, the field has significant momentum and stability. Nevertheless, it will require scientific guidance and coordination going forward. With an appropriate commitment of resources from member states, the IOC HAB program can continue to be a major factor in the sustained growth of this important scientific discipline and its delivery of improved observation and management systems.
    Beschreibung: Supported in part by the following grants to D.M. Anderson: NOAA Cooperative Agreement NA17RJ1223, NOAA Grant NA09NOS4260212, NIEHS Grant 1 P50 ES01274201, and NSF Grants OCE-0430724 and OCE-0911031.
    Repository-Name: Woods Hole Open Access Server
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  • 5
    Publikationsdatum: 2022-05-25
    Beschreibung: Author Posting. © The Author(s), 2010. This is the author's version of the work. It is posted here by permission of Springer for personal use, not for redistribution. The definitive version was published in Journal of Applied Phycology 24 (2012): 751-758, doi:10.1007/s10811-011-9694-z.
    Beschreibung: Four methods commonly used to count phytoplankton were evaluated based upon the precision of concentration estimates: Sedgewick Rafter and membrane filter direct counts, flow cytometry, and flow-based imaging cytometry (FlowCAM). Counting methods were all able to estimate the cell concentrations, categorize cells into size classes, and determine cell viability using fluorescent probes. These criteria are essential to determine whether discharged ballast water complies with international standards that limit the concentration of viable planktonic organisms based on size class. Samples containing unknown concentrations of live and UV-inactivated phytoflagellates (Tetraselmis impellucida) were formulated to have low concentrations (〈100 ml-1) of viable phytoplankton. All count methods used chlorophyll a fluorescence to detect cells and SYTOX fluorescence to detect non-viable cells. With the exception of one sample, the methods generated live and non-viable cell counts that were significantly different from each other, although estimates were generally within 100% of the ensemble mean of all subsamples from all methods. Overall, percent coefficient of variation (CV) among sample replicates was lowest in membrane filtration sample replicates, and CVs for all four counting methods were usually lower than 30% (although instances of ~60% were observed). Since all four methods were generally appropriate for monitoring discharged ballast water, ancillary considerations (e.g., ease of analysis, sample processing rate, sample size, etc.) become critical factors for choosing the optimal phytoplankton counting method.
    Beschreibung: This study was supported by the U.S. Coast Guard Research and Development Center under contract HSCG32-07- X-R00018. Partial research support to DMA and DMK was provided through NSF International Contract 03/06/394, and Environmental Protection Agency Grant RD-83382801-0.
    Schlagwort(e): Phytoplankton ; Enumeration ; FlowCAM ; Flow cytometry ; Sedgewick Rafter ; Ballast water ; SYTOX Green ; CellTracker Green
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  • 6
    Publikationsdatum: 2022-05-25
    Beschreibung: © The Author(s), 2012. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Ecology and Evolution 2 (2012): 2588–2599, doi:10.1002/ece3.373.
    Beschreibung: In Massachusetts, paralytic shellfish poisoning (PSP) is annually recurrent along the coastline, including within several small embayments on Cape Cod. One such system, the Nauset Marsh System (NMS), supports extensive marshes and a thriving shellfishing industry. Over the last decade, PSP in the NMS has grown significantly worse; however, the origins and dynamics of the toxic Alexandrium fundyense (Balech) populations that bloom within the NMS are not well known. This study examined a collection of 412 strains isolated from the NMS and the Gulf of Maine (GOM) in 2006–2007 to investigate the genetic characteristics of localized blooms and assess connectivity with coastal populations. Comparisons of genetic differentiation showed that A. fundyense blooms in the NMS exhibited extensive clonal diversity and were genetically distinct from populations in the GOM. In both project years, genetic differentiation was observed among temporal samples collected from the NMS, sometimes occurring on the order of approximately 7 days. The underlying reasons for temporal differentiation are unknown, but may be due, in part, to life-cycle characteristics unique to the populations in shallow embayments, or possibly driven by selection from parasitism and zooplankton grazing; these results highlight the need to investigate the role of selective forces in the genetic dynamics of bloom populations. The small geographic scale and limited connectivity of NMS salt ponds provide a novel system for investigating regulators of blooms, as well as the influence of selective forces on population structure, all of which are otherwise difficult or impossible to study in the adjacent open-coastal waters or within larger estuaries.
    Beschreibung: This study was funded through the Woods Hole Center for Oceans and Human Health, National Science Foundation OCE-0430724 and National Institutes of Health 1 P50 ES012742-01, and National Science Foundation OCE-0911031. Funding was also provided by NOAA Grant NA06NOS4780245.
    Schlagwort(e): Alexandrium ; Amoebophrya ; Dinoflagellate ; Gulf of Maine ; Microsatellites ; Nauset Marsh ; Paralytic shellfish poisoning
    Repository-Name: Woods Hole Open Access Server
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  • 7
    Publikationsdatum: 2022-05-25
    Beschreibung: Author Posting. © The Author(s), 2012. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Deep Sea Research Part II: Topical Studies in Oceanography 103 (2014): 163-173, doi:10.1016/j.dsr2.2012.11.002.
    Beschreibung: A series of oceanographic surveys on Georges Bank document variability of populations of the toxic dinoflagellate Alexandrium fundyense on time scales ranging from synoptic to seasonal to interannual. Blooms of A. fundyense on Georges Bank can reach concentrations on the order of 104 cells l-1, and are generally bank-wide in extent. Georges Bank populations of A. fundyense appear to be quasi-independent of those in the adjacent coastal Gulf of Maine, insofar as they occupy a hydrographic niche that is colder and saltier than their coastal counterparts. In contrast to coastal populations that rely on abundant resting cysts for bloom initiation, very few cysts are present in the sediments on Georges Bank. Bloom dynamics must therefore be largely controlled by the balance between growth and mortality processes, which are at present largely unknown for this population. Based on correlations between cell abundance and nutrient distributions, ammonium appears to be an important source of nitrogen for A. fundyense blooms on Georges Bank.
    Beschreibung: We appreciate financial support of the National Oceanic Atmospheric Administration (grant NA06NOS4780245 for the Gulf of Maine Toxicity (GOMTOX) program) and the Woods Hole Center for Oceans and Human Health through National Science Foundation grants OCE-0430724 and OCE-0911031 and National Institute of Environmental Health Sciences grant 1P50-ES01274201.
    Schlagwort(e): Phytoplankton ; Population dynamics ; Red tides ; Paralytic shellfish poisoning ; USA ; Gulf of Maine ; Georges Bank
    Repository-Name: Woods Hole Open Access Server
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  • 8
    Publikationsdatum: 2022-05-25
    Beschreibung: Author Posting. © The Author(s), 2014. This is the author's version of the work. It is posted here by permission of Elsevier for personal use, not for redistribution. The definitive version was published in Harmful Algae 34 (2014): 56–68, doi:10.1016/j.hal.2014.02.007.
    Beschreibung: Ciguatera is a serious seafood poisoning syndrome caused by the consumption of ciguatoxin-contaminated finfish from tropical and subtropical regions. This study examined the community structure of ciguatera-associated dinoflagellates and the distribution pattern, taxonomy and toxicity of Gambierdiscus spp. from a high-risk area of Marakei, Republic of Kiribati. The genera Gambierdiscus, Prorocentrum, Ostreopsis, Amphidinium and Coolia were present, and generally the former three dominated the dinoflagellate assemblage. Among these three, Gambierdiscus was the most abundant dinoflagellate genus observed at three of the four sites sampled, two of which (Sites 1 and 2) were on the northern half of the island and two (Sites 3 and 4) on the southern half. The following patterns of abundance were observed among sites: (1) Average Gambierdiscus spp. abundance at the northern sites exceeded the southern sites by a factor of 19-54; and (2) Gambierdiscus spp. abundance at shallow sites (2-3 m) exceeded deeper sites (10-15 m). The distribution of Gambierdiscus spp. at Marakei corresponded with previously observed patterns of fish toxicity, with fish from southern locations being much less toxic than fish sampled north of the central channel. DNA sequencing identified three Gambierdiscus species (G. carpenteri, G. belizeanus, G. pacificus) and three previously unreported ribotypes (Gambierdiscus sp. type 4, Gambierdiscus sp. type 5, Gambierdiscus sp. type 6) in the samples; Gambierdiscus sp. type 4 may represent a Pacific clade of Gambierdiscus sp. ribotype 1. Toxicity analyses determined that Gambierdiscus sp. type 4 isolates were more toxic than the Gambierdiscus sp. type 5 and G. pacificus isolates, with toxin contents of 2.6-6.0 (mean: 4.3± 1.4), 0.010 and 0.011 fg P-CTX-1 eq cell-1, respectively. Despite low densities of Gambierdiscus spp. observed at Marakei relative to other studies in other parts of the world, the presence of low and moderately toxic populations may be sufficient to render the western coast of Marakei a high-risk area for ciguatera. The long history of toxicity along the western side of Marakei suggests that large-scale oceanographic forcings that regulate the distribution of Gambierdiscus spp. along the western side of Marakei may have remained relatively stable over that time. Chronic as well as acute exposure to ciguatoxins may therefore pose an important human health impact to the residents of Marakei.
    Beschreibung: Funding for this work was provided by the Centers for Disease Control and Prevention (U01 EH000421), USFDA (F223201000060C), NOAA NOS (Cooperative Agreement NA11NOS4780060, NA11NOS4780028), National Program on Key Basic Research Project of China (973 Program, 2013CB956503), the Nonprofit Research Project for the State Oceanic Administration (China, 201005006-01), and the National Natural Science Foundation of China (41276110).
    Schlagwort(e): Ciguatera fish poisoning ; Ciguatoxins ; Gambierdiscus ; Ostreopsis ; HABs ; Kiribati
    Repository-Name: Woods Hole Open Access Server
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  • 9
    Publikationsdatum: 2022-05-25
    Beschreibung: Author Posting. © The Author(s), 2011. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Harmful Algae (2011): 381-387, doi:10.1016/j.hal.2011.01.003.
    Beschreibung: A new method was developed for marine harmful algal bloom (HAB) mitigation using local beach sand or silica sand modified with chitosan and polyaluminum chloride (PAC). Untreated sand was ineffective in flocculating algal cells, but 80% removal efficiency was achieved for Amphidinium carterae Hulburt and a Chlorella sp. in 3 min (t80 = 3 min) using 120 mg L-1 sand modified with 10 mg L-1 PAC and 10 mg L-1 chitosan. After several hours 92% – 96% removal was achieved. The t80 for removing A. carterae using the modifiers only (PAC and chitosan combined) was 60 min and for Chlorella sp. 120 min, times which are much slower than with the corresponding modified sand. Sands were critical for speeding up the kinetic processes of flocculation and sedimentation of algal flocs. PAC was helpful in forming small flocs and chitosan is essential to bridge the small flocs into large dense flocs. Chitosan was also important in inhibiting the escape of cells from the flocs. Chitosan and PAC used together as modifiers make it possible to use local beach sands for HAB mitigation in seawater. Economical and environmental concerns could be reduced through the use of sands and biodegradable chitosan, but the potential impacts of PAC need further study.
    Beschreibung: The research was funded by the National Key Project for Basic Research (2008CB418105, 2010CB933600). Support for DMA was provided by GOMTOX program through NOAA Grant NA06NOS4780245. Additional support came from NSF grant OCE-0430724, DMS-0417769 and NIEHS grant 1P50-ES01274201 (Woods Hole Center for Oceans and Human Health).
    Schlagwort(e): Harmful algal bloom ; Seawater ; Modified sands ; Chitosan ; Polyaluminum chloride (PAC) ; Synergistic effect
    Repository-Name: Woods Hole Open Access Server
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  • 10
    Publikationsdatum: 2022-05-25
    Beschreibung: Author Posting. © The Author(s), 2011. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Harmful Algae 12 (2011): 26–38, doi:10.1016/j.hal.2011.08.009.
    Beschreibung: Paralytic Shellfish Poisoning (PSP) toxins are annually recurrent along the Massachusetts coastline (USA), which includes many small embayments and salt ponds. Among these is the Nauset Marsh System (NMS), which has a long history of PSP toxicity. Little is known, however, about the bloom dynamics of the causative organism Alexandrium fundyense within that economically and socially important system. The overall goal of this work was to characterize the distribution and dynamics of A. fundyense blooms within the NMS and adjacent coastal waters by documenting the distribution and abundance of resting cysts and vegetative cells. Cysts were found predominantly in three drowned kettle holes or salt ponds at the distal ends of the NMS - Salt Pond, Mill Pond, and Town Cove. The central region of the NMS had a much lower concentration of cysts. Two types of A. fundyense blooms were observed. One originated entirely within the estuary, seeded by cysts in the three seedbeds. These blooms developed independently of each other and of the A. fundyense population observed in adjacent coastal waters outside the NMS. The temporal development of the blooms was different in the three salt ponds, with initiation differing by as much as 30 days. These differences do not appear to reflect the initial cyst abundances in these locations, and may simply result from higher cell retention and higher nutrient concentrations in Mill Pond, the first site to bloom. Germination of cysts accounted for a small percentage of the peak cell densities in the ponds, so population size was influenced more by the factors affecting growth than by cyst abundance. Subsurface cell aggregation (surface avoidance) limited advection of the vegetative A. fundyense cells out of the salt ponds through the shallow inlet channels. Thus, the upper reaches of the NMS are at the greatest risk for PSP since the highest cyst abundances and cell concentrations were found there. After these localized blooms in the salt ponds peaked and declined, a second, late season bloom occurred within the central portions of the NMS. The timing of this second bloom relative to those within the salt ponds and the coastal circulation patterns at that time strongly suggest that those cells originated from a regional A. fundyense bloom in the Gulf of Maine, delivered to the central marsh from coastal waters outside the NMS through Nauset Inlet. These results will guide policy decisions about water quality as well as shellfish monitoring and utilization within the NMS and highlight the potential for “surgical” closures of shellfish during PSP events, leaving some areas open for harvesting while others are closed.
    Beschreibung: This work was supported by NOAA Grant NA06OAR4170021, NPS Grant H238015504 and by the Woods Hole Center for Oceans and Human Health through NSF Grants OCE-0911031 and OCE-0430724 and NIEHS Grant 1P50-ES01274201. B.G.C. was supported by a Xunta de Galicia Ángeles Alvariño fellowship and the Stanley W. Watson Chair for Excellence in Oceanography under a Postdoctoral program at the Woods Hole Oceanographic Institution.
    Schlagwort(e): Paralytic shellfish poisoning ; Alexandrium fundyense ; Dinoflagellate cysts ; Bloom dynamics ; Retention mechanism ; Nauset Marsh System
    Repository-Name: Woods Hole Open Access Server
    Materialart: Preprint
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