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  • 1
    Book
    Book
    Toxic marine phytoplankton : proceedings of the Fourth International Conference on Toxic Marine Phytoplankton, held June 26 - 30, 1989, in Lund, Sweden (1990)
    New York, NY [u.a.] : Elsevier
    Details Availability
    Keywords: Marine phytoplankton Toxicology ; Congresses ; Toxic marine algae Toxicology ; Congresses ; Marine toxins Congresses ; Konferenzschrift ; Konferenzschrift 1989 ; Meer ; Phytoplankton ; Toxikologie ; Meer ; Phytoplankton ; Wasserblüte
    Type of Medium: Book
    Pages: XXI, 554 S. , Ill., graph. Darst., Kt.
    ISBN: 044401523X
    URL: https://external.dandelon.com/download/attachments/dandelon/ids/DE0067DA226EB1EFA465BC1257A3600458B44.pdf
    DDC: 615.9/5294
    Language: English
    Note: Includes bibliographical references
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  • 2
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    The ecophysiology and bloom dynamics of Prymnesium spp. (2012)
    Elsevier
    Details
    Publication Date: 2023-02-15
    Description: Members of Prymnesium belong to the division Haptophyta, class Prymnesiophyceae, order Prymnesiales and family Prymnesiaceae. As most haptophytes, members of the genus Prymnesium are unicellular and planktonic. The most known of these species is the ichthyotoxic P. parvum, which may form nearly monospecific dense blooms in coastal and inland waters. This species possesses extraordinary plasticity concerning life survival strategies, and is specifically addressed in this review. Toxins produced by P. parvum have hemolytic properties, that not only kill fish but also co-existing plankton. These substances are allelopathic (when other algae are killed) and grazer deterrent (when grazers are killed). Allelopathy enables P. parvum to utilize inorganic nutrients present in the surrounding water without competition from other algal species; and by eliminating its grazers P. parvum reduces cell losses. The paralized microalgae and/or zooplankton, are therefter ingested by the P. parvum cells, a process called phagotrophy. P. parvum is also able of osmotrophy, i.e. utilization of dissolved organic matter. In this review, the cellular characteristics, life cycles, bloom formation, and factors affecting toxicity, allelopathy, phagotrophy, and osmotrophy of P. parvum are discussed.
    Type: Article , PeerReviewed
    Format: text
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  • 3
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    Nitrogen uptake kinetics of Prymnesium parvum (Haptophyte) (2011)
    Elsevier
    Details
    Publication Date: 2023-02-15
    Description: The uptake rates of different nitrogen (N) forms (NO3−, urea, and the amino acids glycine and glutamic acid) by N-deficient, laboratory-grown cells of the mixotrophic haptophyte, Prymnesium parvum, were measured and the preference by the cells for the different forms determined. Cellular N uptake rates (ρcell, fmol N cell−1 h−1) were measured using 15N-labeled N substrates. P. parvum showed high preference for the tested amino acids, in particular glutamic acid, over urea and NO3− under the culture nutrient conditions. However, extrapolating these rates to Baltic Seawater summer conditions, P. parvum would be expected to show higher uptake rates of NO3− and the amino acids relative to urea because of the difference in average concentrations of these substrates. A high uptake rate of glutamic acid at low substrate concentrations suggests that this substrate is likely used through extracellular enzymes. Nitrate, urea and glycine, on the other hand, showed a non-saturating uptake over the tested substrate concentration (1–40 μM-N for NO3− and urea, 0.5–10 μM-N for glycine), indicating slower membrane-transport rates for these substrates.
    Type: Article , PeerReviewed
    Format: text
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  • 4
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    Contribution of phagotrophy versus autotrophy to Prymnesium parvum growth under nitrogen and phosphorus sufficiency and deficiency (2010)
    Elsevier
    Details
    Publication Date: 2023-02-15
    Description: Laboratory experiments were conducted to test the effects of nitrogen (N) and phosphorus (P) sufficiency and deficiency on mixotrophy in Prymnesium parvum (Haptophyta). P. parvum was grown with and without algal prey (Rhodomonas salina) and observed for 120 h. Detection and enumeration of cells containing food vacuoles with prey (i.e. phagotrophy) was based on flow cytometric detection of fluorescence of an acidotropic probe. Overall, the presence of R. salina increased phagotrophy in P. parvum suggesting that, at least in this strain of P. parvum, the presence of suitable prey can stimulate phagotrophic behavior in P. parvum. Feeding frequency (the percentage of P. parvum cells containing food vacuoles in a given time) was significantly higher under N and P deficiency than in the nutrient-sufficient treatments. A nutrient budget constructed from the data indicated that ingestion of organic matter (OM) supplied with 78 ± 7% of the N (3.9 ± 0.3 μM) incorporated by P. parvum in the N-deficient treatment, and 45 ± 9% of the P (0.3 ± 0 μM) acquired in the P-deficient cultures. Even under nutrient sufficiency, ingestion of OM was estimated to have supplied 43 ± 16% of the N and 48 ± 16% of the P incorporated into P. parvum cells. Phagotrophy was observed even in the NP-sufficient cultures (non-axenic mixed and monocultures), although P. parvum cells did not lose their photosynthetic capability, suggesting that phagotrophy is probably a permanent nutritional adaptation to this species. The ingestion of organic nutrients played an important role in P. parvum growth, being a reliable source of nutrition for P. parvum inorganic nutrient limitation, and could explain its capabilities to form persistent blooms.
    Type: Article , PeerReviewed
    Format: text
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  • 5
    Electronic Resource
    Electronic Resource
    Modeling the increase of nodularin content in Baltic Sea Nodularia spumigena during stationary phase in phosphorus-limited batch cultures (2002)
    Oxford, UK : Blackwell Publishing Ltd
    FEMS microbiology ecology 41 (2002), S. 0 
    Details
    ISSN: 1574-6941
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Nodularin (Nod), produced by the brackish/marine cyanobacterium Nodularia spumigena, is a potent hepatotoxin, tumor promoter and is possibly carcinogenic to mammals. It is structurally and toxicologically related to the microcystins, produced by Microcystis aeruginosa in fresh water. A better understanding of the kinetics of Nod production might provide an insight into the physiological and ecological function of cyanobacterial hepatotoxins. The present study presents a simple model simulating the concentration of Nod in N. spumigena KAC66 during phosphorus-limited growth. The main assumption of the model is that the Nod production rate is proportional to the chlorophyll-a (Chla) concentration. The model was tuned to data from phosphorus-limited batch cultures of N. spumigena KAC66 at saturating light and was able to predict 96% or more of the variation in both Chla and Nod concentration. No significant effect of available nitrogen source was found on the Chla-specific Nod production rate although specific growth rates were higher in ammonium and nitrate grown cultures compared to cultures grown with N2 as the sole nitrogen source. Literature data on microcystin production by M. aeruginosa in phosphorus-limited chemostats fitted the model predictions well, except at very low dilution rates (0.1 day−1). The good fit with the proposed model to our own and literature data suggests that the production of hepatotoxic cyanotoxins is not regulated upon growth reduction due to phosphate limitation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1574-6941.2002.tb00982.x
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  • 6
    Electronic Resource
    Electronic Resource
    The role of C, N and P in dissolved and particulate organic matter as a nutrient source for phytoplankton growth, including toxic species (1999)
    Springer
    Aquatic ecology 33 (1999), S. 17-27 
    Details
    ISSN: 1573-5125
    Keywords: dissolved organic substances ; harmful phytoplankton ; macronutrients ; mixotrophy ; osmotrophy ; phagotrophy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Phytoplankton have traditionally been regarded as strictly phototrophic, with a well defined position at the base of pelagic food webs. However, recently we have learned that the nutritional demands of a growing number of phytoplankton species can be met, at least partially, or under specific environmental conditions, through heterotrophy. Mixotrophy is the ability of an organism to be both phototrophic and heterotrophic, in the latter case utilizing either organic particles (phagotrophy) or dissolved organic substances (osmotrophy). This finding has direct implications for our view on algal survival strategies, particularly for harmful species, and energy- and nutrient flow in pelagic food webs. Mixotrophic species may outcompete strict autotrophs, e.g. in waters poor in inorganic nutrients or under low light. In the traditional view of the ‘microbial loop’ DOC is thought to be channeled from algal photosynthesis to bacteria and then up the food chain through heterotrophic flagellates, ciliates and mesozooplankton. Are mixotrophic phytoplankton that feed on bacteria also significantly contributing to this transport of photosynthetic carbon up the food chain? How can we estimate the fluxes of carbon and nutrients between different trophic levels in the plankton food web involving phagotrophic algae? These questions largely remain unanswered. In this review we treat evidence for both osmotrophy and phagotrophy in phytoplankton, especially toxic marine species, and some ecological implications of mixotrophy.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009925515059
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  • 7
    Electronic Resource
    Electronic Resource
    Evidence for multiple species within the endoparasitic dinoflagellate Amoebophrya ceratii as based on 18S rRNA gene-sequence analysis (2000)
    Springer
    Parasitology research 86 (2000), S. 929-933 
    Details
    ISSN: 1432-1955
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Parasitism within the group of dinoflagellates is a widespread phenomenon. Whether the parasitic dinoflagellates exhibit specificity in their infection is not well known, but this possibility has become an important issue in the development of biological control of harmful algal blooms. The 18S rDNA sequences from the parasite Amoebophrya sp. and its dinoflagellate host Dinophysis norvegica were determined and compared with the published sequence of Amoebophrya sp. infecting Gymnodinium sanguineum and other dinoflagellates. The results showed that the sequence from the parasite within D. norvegica was clustered with that of the one from G. sanguineum with 100% bootstrap support in a maximum-likelihood analysis. The observed identity between these two sequences was 93%, which indicates that they are not identical species. The two sequences from Amoebophrya sp. were deeply branched within the group of dinoflagellate sequences and represent the earliest diverging dinoflagellates. The sequence from the parasite Parvilucifera infectans, also infecting D. norvegica, was not closely related to the Amoebophrya sp. sequences. The sequence from D. norvegica appeared as a sister group to a cluster containing Prorocentrum lima and Alexandrium spp. without significant bootstrap support. The data presented herein support the hypothesis that A. ceratii comprises more than one species, and this opens the possibility that infections of harmful algal species might involve more than one Amoebophrya species.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004360000272
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  • 8
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    Defining Planktonic Protist Functional Groups on Mechanisms for Energy and Nutrient Acquisition: Incorporation of Diverse Mixotrophic Strategies (2016)
    ELSEVIER GMBH
    In:  EPIC3Protist, ELSEVIER GMBH, 167, pp. 106-120, ISSN: 1434-4610
    Details
    Publication Date: 2019-07-17
    Description: Arranging organisms into functional groups aids ecological research by grouping organisms (irrespective of phylogenetic origin) that interact with environmental factors in similar ways. Planktonic protists traditionally have been split between photoautotrophic “phytoplankton” and phagotrophic “microzoo-plankton”. However, there is a growing recognition of the importance of mixotrophy in euphotic aquatic systems, where many protists often combine photoautotrophic and phagotrophic modes of nutrition. Such organisms do not align with the traditional dichotomy of phytoplankton and microzooplankton. To reflect this understanding,we propose a new functional grouping of planktonic protists in an eco- physiological context: (i) phagoheterotrophs lacking phototrophic capacity, (ii) photoautotrophs lacking phagotrophic capacity,(iii) constitutive mixotrophs (CMs) as phagotrophs with an inherent capacity for phototrophy, and (iv) non-constitutive mixotrophs (NCMs) that acquire their phototrophic capacity by ingesting specific (SNCM) or general non-specific (GNCM) prey. For the first time, we incorporate these functional groups within a foodweb structure and show, using model outputs, that there is scope for significant changes in trophic dynamics depending on the protist functional type description. Accord- ingly, to better reflect the role of mixotrophy, we recommend that as important tools for explanatory and predictive research, aquatic food-web and biogeochemical models need to redefine the protist groups within their frameworks.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Format: application/pdf
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  • 9
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    The rise and dominance of mixotrophic protists in a changing world - Refining the functionality of the biological & microbial carbon pumps (2013)
    In:  EPIC3The future of marine biogeochemistry, ecosystems and societies. IMBIZO III, Goa, India, 2013-01-28-2013-01-31
    Details
    Publication Date: 2019-07-17
    Repository Name: EPIC Alfred Wegener Institut
    Type: Conference , notRev
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  • 10
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    The role of mixotrophic protists in the biological carbon pump (2014)
    COPERNICUS GESELLSCHAFT MBH
    In:  EPIC3Biogeosciences, COPERNICUS GESELLSCHAFT MBH, 11(4), pp. 995-1005, ISSN: 1726-4170
    Details
    Publication Date: 2019-07-17
    Description: The traditional view of the planktonic food web describes consumption of inorganic nutrients by photoautotrophic phytoplankton, which in turn supports zooplankton and ultimately higher trophic levels. Pathways centred on bacteria provide mechanisms for nutrient recycling. This structure lies at the foundation of most models used to explore biogeochemical cycling, functioning of the biological pump, and the impact of climate change on these processes. We suggest an alternative new paradigm, which sees the bulk of the base of this food web supported by protist plankton communities that are mixotrophic – combining phototrophy and phagotrophy within a single cell. The photoautotrophic eukaryotic plankton and their heterotrophic microzooplankton grazers dominate only during the developmental phases of ecosystems (e.g. spring bloom in temperate systems). With their flexible nutrition, mixotrophic protists dominate in more-mature systems (e.g. temperate summer, established eutrophic systems and oligotrophic systems); the more-stable water columns suggested under climate change may also be expected to favour these mixotrophs. We explore how such a predominantly mixotrophic structure affects microbial trophic dynamics and the biological pump. The mixotroph-dominated structure differs fundamentally in its flow of energy and nutrients, with a shortened and potentially more efficient chain from nutrient regeneration to primary production. Furthermore, mixotrophy enables a direct conduit for the support of primary production from bacterial production. We show how the exclusion of an explicit mixotrophic component in studies of the pelagic microbial communities leads to a failure to capture the true dynamics of the carbon flow. In order to prevent a misinterpretation of the full implications of climate change upon biogeochemical cycling and the functioning of the biological pump, we recommend inclusion of multi-nutrient mixotroph models within ecosystem studies.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
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