GLORIA

GEOMAR Library Ocean Research Information Access

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 11
    facet.materialart.
    Unknown
    Remarkable structural resistance of a nanoflagellatedominated plankton community to iron fertilization during the Southern Ocean experiment LOHAFEX (2018)
    In:  EPIC3MARINE ECOLOGY PROGRESS SERIES, 601, pp. 77-95
    Details
    Publication Date: 2019-08-19
    Description: The genesis of phytoplankton blooms and the fate of their biomass in iron-limited, high-nutrient−low-chlorophyll regions can be studied under natural conditions with ocean iron fertilization (OIF) experiments. The Indo-German OIF experiment LOHAFEX was carried out over 40 d in late summer 2009 within the cold core of a mesoscale eddy in the productive southwest Atlantic sector of the Southern Ocean. Silicate concentrations were very low, and phytoplankton biomass was dominated by autotrophic nanoflagellates (ANF) in the size range 3−10 μm. As in all previous OIF experiments, the phytoplankton responded to iron fertilization by increasing the maximum quantum yield (Fv/Fm) and cellular chlorophyll levels. Within 3 wk, chlorophyll levels tripled and ANF biomass doubled. With the exception of some diatoms and dinoflagellates, the biomass levels of all other groups of the phyto- and protozooplankton (heterotrophic nanoflagellates, dinoflagellates and ciliates) remained remarkably stable throughout the experiment both inside and outside the fertilized patch. We attribute the unusually high biomass attained and maintained by ANF to the absence of their grazers, the salps, and to constraints on protozooplankton grazers by heavy predation exerted by the large copepod stock. The resistance to change of the ecosystem structure over 38 d after fertilization, indicated by homogeneity at regional and temporal scales, suggests that it was locked into a stable, mature state that had evolved in the course of the seasonal cycle. The LOHAFEX bloom provides a case study of a resistant/robust dynamic equilibrium between auto- and heterotrophic ecosystem components resulting in low vertical flux both inside and outside the patch despite high biomass levels.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Format: application/pdf
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    PAPER (OA)
  • 12
    facet.materialart.
    Unknown
    Harmful Algal Blooms in Fjords, Coastal Embayments, and Stratified Systems: Recent Progress and Future Research (2017)
    The Oceanography Society
    In:  EPIC3Oceanography, The Oceanography Society, 30(1), pp. 46-57
    Details
    Publication Date: 2017-05-29
    Description: Harmful algal blooms (HABs) are natural phenomena that result from the interplay of biological, chemical, physical, and sedimentary processes occurring at different temporal and spatial scales. This paper provides an integrated description of HAB dynamics occurring at the mesoscale (10–100 km, sensu Haury et al., 1978) in confined and semi-confined coastal environments and under stratified water column conditions in a diversity of habitats where HAB events occur. It also focuses on relevant aspects occurring at fine-scale and even smaller cellular scales that are critical to species interactions with their environments. Examples include the key role of life-history stages in the recurrence of HABs in certain embayments; the physical-biological interactions driving the formation, maintenance, and decline of thin layers of plankton, including harmful microalgae; the fascinating, but poorly understood, domain of small-scale chemical interactions between HAB species and components of the food web; the potential link between human activities and climate change; and the trends in HAB occurrence. Development of new observing and sampling technologies and of new modeling approaches has resulted in greater understanding of these phenomena. Two Core Research Projects initiated under the GEOHAB Implementation Strategy, “HABs in Fjords and Coastal Embayments” and “HABs in Stratified Systems,” are discussed and priorities for future research toward improving the management and mitigation of HAB impacts are outlined.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Format: application/pdf
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    PAPER (OA)
  • 13
    facet.materialart.
    Unknown
    Response of the protozooplankton assemblage during the European Iron Fertilization Experiment (EIFEX) in the Antarctic circumpolar current (2014)
    OXFORD UNIV PRESS
    In:  EPIC3Journal of Plankton Research, OXFORD UNIV PRESS, 36(5), pp. 1175-1189, ISSN: 0142-7873
    Details
    Publication Date: 2014-09-24
    Description: Ocean iron fertilization experiments enable the quantitative study of processes shaping the structure and functioning of pelagic ecosystems following perturbation under in situ conditions. EIFEX was conducted within a stationary eddy adjacent to the Antarctic Polar Front over 38 days in February/March 2004 and induced a massive diatom bloom. Here, we present the responses in abundance and biomass of all identifiable protozooplankton taxa (heterotrophic protists ranging from 2 to 500 µm) during the bloom. Acantharia, dinoflagellates and ciliates together contributed 〉90% of protozooplankton biomass in the upper 100 m throughout the experiment with heterotrophic nanoflagellates, nassellaria, spumellaria, phaeodaria, foraminifera and the taxopodidean Sticholonche zanclea providing the remainder. Total protozooplankton biomass increased slightly from 1.0 to 1.3 g C m−2 within the fertilized patch and remained at 0.7+0.04 g C m−2 outside it. However, distinct trends in population build-up or decline were observed within the dominant taxa in each group. In general, smaller less-defended groups such as aloricate ciliates and athecate dinoflagellates declined, whereas the biomass of large, spiny and armoured groups, in particular acantharia, large tintinnids and thecate dinoflagellates increased inside the patch. We attribute the higher accumulation rates of defended taxa to selective, heavy grazing pressure by the large stocks of copepods. Of the defended taxa, acantharia had the lowest mortality rates and the highest biomass. Large stocks of tintinnid loricae in the deep water column identify this group as a relevant contributor to deep organic carbon export. Highest accumulation rates (0.11 day−1) were recorded in S. zanclea.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Format: application/pdf
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    PAPER (OA)
  • 14
    facet.materialart.
    Unknown
    (2302) Proposal to reject the name Gonyaulax catenella (Alexandrium catenella) (Dinophyceae) (2014)
    International Association for Plant Taxonomy
    In:  EPIC3Taxon, International Association for Plant Taxonomy, 63(4), pp. 932-933, ISSN: 0040-0262
    Details
    Publication Date: 2014-10-07
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Format: application/pdf
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    PAPER (OA)
  • 15
    facet.materialart.
    Unknown
    Deep carbon export from a Southern Ocean iron-fertilized diatom bloom. (2012)
    Nature
    In:  EPIC3Nature, Nature, 487(7407), pp. 313-319
    Details
    Publication Date: 2019-07-16
    Description: Fertilization of the ocean by adding iron compounds has induced diatom-dominated phytoplankton blooms accompanied by considerable carbon dioxide drawdown in the ocean surface layer. However, because the fate of bloom biomass could not be adequately resolved in these experiments, the timescales of carbon sequestration from the atmosphere are uncertain. Here we report the results of a five-week experiment carried out in the closed core of a vertically coherent, mesoscale eddy of the Antarctic Circumpolar Current, during which we tracked sinking particles from the surface to the deep-sea floor. A large diatom bloom peaked in the fourth week after fertilization. This was followed by mass mortality of several diatom species that formed rapidly sinking, mucilaginous aggregates of entangled cells and chains. Taken together, multiple lines of evidence—although each with important uncertainties—lead us to conclude that at least half the bloom biomass sank far below a depth of 1,000 metres and that a substantial portion is likely to have reached the sea floor. Thus, iron-fertilized diatom blooms may sequester carbon for timescales of centuries in ocean bottom water and for longer in the sediments.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    PAPER (OA)
  • 16
    facet.materialart.
    Unknown
    The globally distributed genus Alexandrium : multifaceted roles in marine ecosystems and impacts on human health (2014)
    Details
    Publication Date: 2022-05-26
    Description: Author Posting. © The Author(s), 2011. 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 14 (2012): 10-35, doi:10.1016/j.hal.2011.10.012.
    Description: The dinoflagellate genus Alexandrium is one of the major harmful algal bloom (HAB) genera with respect to the diversity, magnitude and consequences of blooms. The ability of Alexandrium to colonize multiple habitats and to persist over large regions through time is testimony to the adaptability and resilience of this group of species. Three different families of toxins, as well as an as yet incompletely characterized suite of allelochemicals are produced among Alexandrium species. Nutritional strategies are equally diverse, including the ability to utilize a range of inorganic and organic nutrient sources, and feeding by ingestion of other organisms. Many Alexandrium species have complex life histories that include sexuality and often, but not always, cyst formation, which is characteristic of a meroplanktonic life strategy and offers considerable ecological advantages. Due to the public health and ecosystem impacts of Alexandrium blooms, the genus has been extensively studied, and there exists a broad knowledge base that ranges from taxonomy and phylogeny through genomics and toxin biosynthesis to bloom dynamics and modeling. Here we present a review of the genus Alexandrium, focusing on the major toxic and otherwise harmful species.
    Description: Support to DMA was provided by the National Institute of Environmental Health Sciences (1-P50-ES012742) and the National Science Foundation through the Woods Hole Center for Oceans and Human Health (OCE-0430724), and by NOAA Grants NA09NOS4780193, NA06OAR4170021 and NA06NOS4780245. Research funding to ADC and previously to TJA was furnished under the PACES Programme (Coast WP2) from the Helmholtz Society initiative Earth and Environment. Support to TJA was obtained by the research funding program LOEWE (Landes-Offensive zur Entwicklung Wissenschaftlich-ökonomischer Exzellenz) of Hesse’s Ministry of Higher Education, Research, and the Arts. Support to EM and YC was provided by grants from the French National Programme “Ecosphère Continentale et Côtière-EC2CO and from the “Fondation pour la Recherche sur la Biodiversité-INVALEX project (AAP-IN-2009- 036).
    Keywords: Alexandrium ; Harmful algal blooms ; HAB ; Biotoxins ; Public health ; Global dispersion
    Repository Name: Woods Hole Open Access Server
    Type: Preprint
    Format: application/pdf
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    PAPER (OA)
  • 17
    facet.materialart.
    Unknown
    The Marine Microbial Eukaryote Transcriptome Sequencing Project (MMETSP) : illuminating the functional diversity of eukaryotic life in the oceans through transcriptome sequencing (2014)
    Public Library of Science
    Details
    Publication Date: 2022-05-26
    Description: © The Author(s), 2014. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in PLoS Biology 12 (2014): e1001889, doi:10.1371/journal.pbio.1001889.
    Description: Microbial ecology is plagued by problems of an abstract nature. Cell sizes are so small and population sizes so large that both are virtually incomprehensible. Niches are so far from our everyday experience as to make their very definition elusive. Organisms that may be abundant and critical to our survival are little understood, seldom described and/or cultured, and sometimes yet to be even seen. One way to confront these problems is to use data of an even more abstract nature: molecular sequence data. Massive environmental nucleic acid sequencing, such as metagenomics or metatranscriptomics, promises functional analysis of microbial communities as a whole, without prior knowledge of which organisms are in the environment or exactly how they are interacting. But sequence-based ecological studies nearly always use a comparative approach, and that requires relevant reference sequences, which are an extremely limited resource when it comes to microbial eukaryotes. In practice, this means sequence databases need to be populated with enormous quantities of data for which we have some certainties about the source. Most important is the taxonomic identity of the organism from which a sequence is derived and as much functional identification of the encoded proteins as possible. In an ideal world, such information would be available as a large set of complete, well-curated, and annotated genomes for all the major organisms from the environment in question. Reality substantially diverges from this ideal, but at least for bacterial molecular ecology, there is a database consisting of thousands of complete genomes from a wide range of taxa, supplemented by a phylogeny-driven approach to diversifying genomics. For eukaryotes, the number of available genomes is far, far fewer, and we have relied much more heavily on random growth of sequence databases, raising the question as to whether this is fit for purpose.
    Description: This project was funded by the Gordon and Betty Moore Foundation (GBMF; Grants GBMF2637 and GBMF3111) to the National Center for Genome Resources (NCGR) and the National Center for Marine Algae and Microbiota (NCMA).
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Format: application/msword
    Format: application/pdf
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    PAPER (OA)
  • 18
    facet.materialart.
    Unknown
    Morphological and phylogenetic data do not support the split of Alexandrium into four genera (2020)
    ELSEVIER SCIENCE BV
    In:  EPIC3Harmful Algae, ELSEVIER SCIENCE BV, 98, pp. 101902, ISSN: 1568-9883
    Details
    Publication Date: 2023-03-13
    Description: A recently published study analyzed the phylogenetic relationship between the genera Centrodinium and Alexandrium, confirming an earlier publication showing the genus Alexandrium as paraphyletic. This most recent manuscript retained the genus Alexandrium, introduced a new genus Episemicolon, resurrected two genera, Gessnerium and Protogonyaulax, and stated that: “The polyphyly [sic] of Alexandrium is solved with the split into four genera”. However, these reintroduced taxa were not based on monophyletic groups. Therefore this work, if accepted, would result in replacing a single paraphyletic taxon with several non-monophyletic ones. The morphological data presented for genus characterization also do not convincingly support taxa delimitations. The combination of weak molecular phylogenetics and the lack of diagnostic traits (i.e., autapomorphies) render the applicability of the concept of limited use. The proposal to split the genus Alexandrium on the basis of our current knowledge is rejected herein. The aim here is not to present an alternative analysis and revision, but to maintain Alexandrium. A better constructed and more phylogenetically accurate revision can and should wait until more complete evidence becomes available and there is a strong reason to revise the genus Alexandrium. The reasons are explained in detail by a review of the available molecular and morphological data for species of the genera Alexandrium and Centrodinium. In addition, cyst morphology and chemotaxonomy are discussed, and the need for integrative taxonomy is highlighted.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Format: application/pdf
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    PAPER (OA)
  • 19
    facet.materialart.
    Unknown
    The globally distributed genus Alexandrium: Multifaceted roles in marine ecosystems and impacts on human health (2012)
    ELSEVIER SCIENCE BV
    In:  EPIC3Harmful Algae, ELSEVIER SCIENCE BV, 10, pp. 10-35, ISSN: 1568-9883
    Details
    Publication Date: 2023-06-21
    Description: The dinoflagellate genus Alexandrium is one of the major harmful algal bloom (HAB) genera with respect to the diversity, magnitude and consequences of blooms. The ability of Alexandrium to colonize multiple habitats and to persist over large regions through time is testimony to the adaptability and resilience of this group of species. Three different families of toxins, as well as an as yet incompletely characterized suite of allelochemicals are produced among Alexandrium species. Nutritional strategies are equally diverse, including the ability to utilize a range of inorganic and organic nutrient sources, and feeding by ingestion of other organisms. Many Alexandrium species have complex life histories that include sexuality and often, but not always, cyst formation, which is characteristic of a meroplanktonic life strategy and offers considerable ecological advantages. Due to the public health and ecosystem impacts of Alexandrium blooms, the genus has been extensively studied, and there exists a broad knowledge base that ranges from taxonomy and phylogeny through genomics and toxin biosynthesis to bloom dynamics and modeling. Here we present a review of the genus Alexandrium, focusing on the major toxic and otherwise harmful species.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Format: application/pdf
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    PAPER (OA)
  • 20
    facet.materialart.
    Unknown
    Multiannual patterns of genetic structure and mating type ratios highlight the complex bloom dynamics of a marine planktonic diatom (2024)
    Springer Nature
    In:  EPIC3Scientific Reports, Springer Nature, 14(1), pp. 6028-6028, ISSN: 2045-2322
    Details
    Publication Date: 2024-04-08
    Description: Understanding the genetic structure of populations and the processes responsible for its spatial and temporal dynamics is vital for assessing species’ adaptability and survival in changing environments. We investigate the genetic fingerprinting of blooming populations of the marine diatom Pseudo-nitzschia multistriata in the Gulf of Naples (Mediterranean Sea) from 2008 to 2020. Strains were genotyped using microsatellite fingerprinting and natural samples were also analysed with Microsatellite Pool-seq Barcoding based on Illumina sequencing of microsatellite loci. Both approaches revealed a clonal expansion event in 2013 and a more stable genetic structure during 2017–2020 compared to previous years. The identification of a mating type (MT) determination gene allowed to assign MT to strains isolated over the years. MTs were generally at equilibrium with two notable exceptions, including the clonal bloom of 2013. The populations exhibited linkage equilibrium in most blooms, indicating that sexual reproduction leads to genetic homogenization. Our findings show that P. multistriata blooms exhibit a dynamic genetic and demographic composition over time, most probably determined by deeper-layer cell inocula. Occasional clonal expansions and MT imbalances can potentially affect the persistence and ecological success of planktonic diatoms.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Format: application/pdf
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    PAPER (OA)
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...