Eunotia

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Bart Van De Vijver - One of the best experts on this subject based on the ideXlab platform.

  • Temporal Evolution of Diatoms in a Temporary Pond Situated in the Massif du Sancy Mountains (Massif Central, France) and Description of a New Pinnularia Species
    Diversity, 2020
    Co-Authors: Aude Beauger, Luc Ector, Elisabeth Allain, Olivier Voldoire, Carlos Wetzel, Bart Van De Vijver
    Abstract:

    A floristic survey was performed on a temporary pond, "Laqui du Seignavoux", situated in the Mont-Dore massif of the French Massif Central, between 2017 and 2019. Except in 2017, each year, we performed four sampling campaigns from April/May to December. Water samples and diatoms were collected. The temporary pond evolved from a poorly mineralized ecosystem due to snow, inducing oligotrophic and oligosaprobic water, well oxygenated in spring, to a more mineralized, less oxygenated, eutrophic-hypereutrophic, and polysaprobic environment in summer. This change in abiotic conditions was found to be linked to the presence of cattle, beginning in May, that trample and excrete in the pond, leading to higher ammonium and nitrate concentrations. During this period, the dominant species were Pinnularia sp., Nitzschia palea, and Nitzschia palea var. tenuirostris. In spring and winter, different species of Eunotia dominated the community such as Eunotia pseudogroenlandica. Finally, light microscopy (LM) and scanning electron microscopy (SEM) observations on a new species of the genus Pinnularia from the temporary pond are presented and the ecological preferences are discussed.

  • The genus Eunotia (Bacillariophyta) in the Falkland Islands and species-area relationships in sub-Antarctic islands
    Diatom Research, 2018
    Co-Authors: Ingrid Jüttner, Bart Van De Vijver, Horst Lange-bertalot, David M. Williams, Luc Ector
    Abstract:

    We document the morphology of 15 species of Eunotia from freshwater habitats in the Falkland Islands using light and electron microscopy, and describe four new species, Eunotia australovalida, Euno...

  • The genus Eunotia on the volcanic island Ile Amsterdam (TAAF, southern Indian ocean).
    Nova Hedwigia issn 0029-5035, 2008
    Co-Authors: Bart Van De Vijver, Louis Beyens, Marc Lebouvier
    Abstract:

    During a preliminary survey of the non-marine diatom flora of the volcanic island, Île Amsterdam (southern Indian Ocean), five species belonging to the genus Eunotia have been found. Apart from Eunotia paludosa var. paludosa and E. muscicola var. muscicola, three appear to be new to science and are described as E. pugilistica Van de Vijver sp. nov., E. lecohui Van de Vijver sp. nov. and E. cocquytiae sp. nov. All species are fully investigated using both LM and SEM techniques. The new taxa are compared with similar species. Notes on their ecology and associated diatom communities are added. Finally, the biogeographical position of Île Amsterdam based on the genus Eunotia is briefly discussed.

  • The epiphytic diatom flora of mosses from Strømness Bay area, South Georgia
    Polar Biology, 1997
    Co-Authors: Bart Van De Vijver, Louis Beyens
    Abstract:

    A total of 104 taxa, belonging to 27 genera, were recorded from 36 moss samples collected in the Stromness Bay area. Cluster analysis revealed two groups of samples. Group 1 consisted of the Achnanthes incognita–Fragilaria germainii assemblage and the Eunotia paludosa var. paludosa assemblage. Group 2 included the Pinnularia borealis assemblage. The major ecological factor dividing the two groups appears to be the moisture content of the samples. Group 1 represents wetter conditions, and the second group is found on very dry mosses. The assemblages of group 1 were separated from each other by pH. The Achnanthes incognita–Fragilaria germainii assemblage occurs in wet mosses with a circumneutral pH. The Eunotia paludosa var. paludosa assemblage prefers bryophyte habitats with low pH values. The size of Pinnularia borealis drops significantly according to the dryness of the moss habitat.

  • Freshwater diatom communities of the Strømness Bay area, South Georgia
    Antarctic Science, 1996
    Co-Authors: Bart Van De Vijver, Louis Beyens
    Abstract:

    Modern diatom samples were collected from 43 sites across the Strømness Bay area of South Georgia. From 115 taxa belonging to 22 six diatom assemblages were distinguished. A CCA-analysis indicated that the assemblages are linked to pH and conductivity ranges, and habitat structure. The Eunotia paludosa var. paludosa - Eunotia subarcuatoides assemblage occurs in small acid water bodies. Samples of the Fragilaria germainii - Pinnularia aff. anglica assemblage are found in pools with a relatively high conductivity. The Fragilaria neoproducta assemblage and the Achnanthes subatomoides - Navicula vitabunda assemblage are mainly found in larger pools and lakes. This relationship between the assemblages and pH was comparable with results found in the testate amoebae fauna of South Georgia.

Luc Ector - One of the best experts on this subject based on the ideXlab platform.

  • Temporal Evolution of Diatoms in a Temporary Pond Situated in the Massif du Sancy Mountains (Massif Central, France) and Description of a New Pinnularia Species
    Diversity, 2020
    Co-Authors: Aude Beauger, Luc Ector, Elisabeth Allain, Olivier Voldoire, Carlos Wetzel, Bart Van De Vijver
    Abstract:

    A floristic survey was performed on a temporary pond, "Laqui du Seignavoux", situated in the Mont-Dore massif of the French Massif Central, between 2017 and 2019. Except in 2017, each year, we performed four sampling campaigns from April/May to December. Water samples and diatoms were collected. The temporary pond evolved from a poorly mineralized ecosystem due to snow, inducing oligotrophic and oligosaprobic water, well oxygenated in spring, to a more mineralized, less oxygenated, eutrophic-hypereutrophic, and polysaprobic environment in summer. This change in abiotic conditions was found to be linked to the presence of cattle, beginning in May, that trample and excrete in the pond, leading to higher ammonium and nitrate concentrations. During this period, the dominant species were Pinnularia sp., Nitzschia palea, and Nitzschia palea var. tenuirostris. In spring and winter, different species of Eunotia dominated the community such as Eunotia pseudogroenlandica. Finally, light microscopy (LM) and scanning electron microscopy (SEM) observations on a new species of the genus Pinnularia from the temporary pond are presented and the ecological preferences are discussed.

  • The genus Eunotia (Bacillariophyta) in the Falkland Islands and species-area relationships in sub-Antarctic islands
    Diatom Research, 2018
    Co-Authors: Ingrid Jüttner, Bart Van De Vijver, Horst Lange-bertalot, David M. Williams, Luc Ector
    Abstract:

    We document the morphology of 15 species of Eunotia from freshwater habitats in the Falkland Islands using light and electron microscopy, and describe four new species, Eunotia australovalida, Euno...

  • Eunotia amazonica sp. nov. (Bacillariophyta), a common stalk-forming species from the Rio Negro basin (Brazilian Amazon)
    European Journal of Phycology, 2018
    Co-Authors: Fabiane Ferreira De Almeida, Luc Ector, Edinaldo Nelson Dos Santos-silva, Carlos E. Wetzel
    Abstract:

    ABSTRACTA new stalk-forming diatom was observed at high relative abundances on periphytic samples collected in the Rio Negro hydrographic basin (Brazilian Amazon) and is here described using light and scanning electron microscopy. We also present ecological preferences of the new species. Eunotia amazonica sp. nov. co-dominated periphytic samples collected during the rainy seasons of 2013 and 2014 near the city of Manaus (Amazonas, Brazil). The main diagnostic feature of the new species is the stalk-forming growth form (‘Cymbella-like’) illustrated here for the first time in the genus Eunotia Ehrenberg. Previous reports on growth forms in common European databases for this genus included colonial (‘ribbon-like’) but also ‘mobile’, ‘fixed by pads’ or ‘without structures of fixation’. We demonstrated that the three dominant Eunotia species in periphytic samples from the Rio Negro all exhibited distinct ‘growth forms’ or habits: Eunotia amazonica sp. nov. (stalked), Eunotia intricans Metzeltin & Lange-Bertal...

  • Eunotia enigmatica sp nov., a new planktonic diatom from Brazil and the transfer of Fragilaria braunii HUSTEDT to the genus Peronia (Bacillariophyceae)
    Fottea, 2017
    Co-Authors: Lívia F. Costa, Luc Ector, Carlos E. Wetzel, David M. Williams, Denise C. Bicudo
    Abstract:

    Eunotia is a diatom genus characterized by a short raphe system restricted to both valve poles and by the presence of rimoportulae. As part of a survey examining the genus, Eunotia enigmatica sp. nov. is described from ultra oligo- to oligotrophic and slightly acidic reservoirs in Sao Paulo State, southeast Brazil. The species is unusual in having a short distinct raphe, and a 'fragilarioid' appearance with long cells and marginal spines. It was commonly found in the planktonic community as well as on sediments of the studied reservoirs. It seems to be adapted to an open water existence, and is similar to E. croatana and E. pseudofragilaria both described from North America. Additionally, type material of another similar looking species, Fragilaria braunii, was analysed using light and scanning electron microscopy and a new combination is proposed for it in the genus Peronia.

  • Article
    2015
    Co-Authors: Fernanda Ferrari, Luc Ector, Carlos E. Wetzel, Denise C. Bicudo, Carlos E. De M
    Abstract:

    A new uncommon epilithic diatom, Eunotia relicta sp. nov., is described from a small oligotrophic, acidic stream in the Chapada Diamantina region, northeast Brazil. Eunotia relicta is a typical eunotioid form with a pronounced arch on the dorsal side of the valve mainly in smaller valves. Contrary to most Eunotia species, Eunotia relicta does not possess rectangular frustules in girdle view. Until now, this characteristic was only observed in a few species such as E. charliereimeri Edlund & Brant, E. sarraceniae E.E. Gaiser & J.R. Johansen and E. arcuoides Foged, all of them considered asymmetric along the valve plane. Some interesting morphological features of the new species are broad copulae on the dorsal side, an inconspicuous single conical spine on the valve face near the margin at both poles, and the irregularly thickened interstriae. Moreover, each valve has irregular projections at the dorsal valve face margin/mantle juncture and up to three rimoportulae per valve located on the mantle. These features associated with the distinct valve outline set it apart from E. charliereimeri, E. sarraceniae and E. arcuoides, which have no spines, smooth valve faces and 1–2 rimoportulae per valve

David M. Williams - One of the best experts on this subject based on the ideXlab platform.

Carlos E. Wetzel - One of the best experts on this subject based on the ideXlab platform.

  • Eunotia amazonica sp. nov. (Bacillariophyta), a common stalk-forming species from the Rio Negro basin (Brazilian Amazon)
    European Journal of Phycology, 2018
    Co-Authors: Fabiane Ferreira De Almeida, Luc Ector, Edinaldo Nelson Dos Santos-silva, Carlos E. Wetzel
    Abstract:

    ABSTRACTA new stalk-forming diatom was observed at high relative abundances on periphytic samples collected in the Rio Negro hydrographic basin (Brazilian Amazon) and is here described using light and scanning electron microscopy. We also present ecological preferences of the new species. Eunotia amazonica sp. nov. co-dominated periphytic samples collected during the rainy seasons of 2013 and 2014 near the city of Manaus (Amazonas, Brazil). The main diagnostic feature of the new species is the stalk-forming growth form (‘Cymbella-like’) illustrated here for the first time in the genus Eunotia Ehrenberg. Previous reports on growth forms in common European databases for this genus included colonial (‘ribbon-like’) but also ‘mobile’, ‘fixed by pads’ or ‘without structures of fixation’. We demonstrated that the three dominant Eunotia species in periphytic samples from the Rio Negro all exhibited distinct ‘growth forms’ or habits: Eunotia amazonica sp. nov. (stalked), Eunotia intricans Metzeltin & Lange-Bertal...

  • Eunotia enigmatica sp nov., a new planktonic diatom from Brazil and the transfer of Fragilaria braunii HUSTEDT to the genus Peronia (Bacillariophyceae)
    Fottea, 2017
    Co-Authors: Lívia F. Costa, Luc Ector, Carlos E. Wetzel, David M. Williams, Denise C. Bicudo
    Abstract:

    Eunotia is a diatom genus characterized by a short raphe system restricted to both valve poles and by the presence of rimoportulae. As part of a survey examining the genus, Eunotia enigmatica sp. nov. is described from ultra oligo- to oligotrophic and slightly acidic reservoirs in Sao Paulo State, southeast Brazil. The species is unusual in having a short distinct raphe, and a 'fragilarioid' appearance with long cells and marginal spines. It was commonly found in the planktonic community as well as on sediments of the studied reservoirs. It seems to be adapted to an open water existence, and is similar to E. croatana and E. pseudofragilaria both described from North America. Additionally, type material of another similar looking species, Fragilaria braunii, was analysed using light and scanning electron microscopy and a new combination is proposed for it in the genus Peronia.

  • Article
    2015
    Co-Authors: Fernanda Ferrari, Luc Ector, Carlos E. Wetzel, Denise C. Bicudo, Carlos E. De M
    Abstract:

    A new uncommon epilithic diatom, Eunotia relicta sp. nov., is described from a small oligotrophic, acidic stream in the Chapada Diamantina region, northeast Brazil. Eunotia relicta is a typical eunotioid form with a pronounced arch on the dorsal side of the valve mainly in smaller valves. Contrary to most Eunotia species, Eunotia relicta does not possess rectangular frustules in girdle view. Until now, this characteristic was only observed in a few species such as E. charliereimeri Edlund & Brant, E. sarraceniae E.E. Gaiser & J.R. Johansen and E. arcuoides Foged, all of them considered asymmetric along the valve plane. Some interesting morphological features of the new species are broad copulae on the dorsal side, an inconspicuous single conical spine on the valve face near the margin at both poles, and the irregularly thickened interstriae. Moreover, each valve has irregular projections at the dorsal valve face margin/mantle juncture and up to three rimoportulae per valve located on the mantle. These features associated with the distinct valve outline set it apart from E. charliereimeri, E. sarraceniae and E. arcuoides, which have no spines, smooth valve faces and 1–2 rimoportulae per valve

  • A new uncommon epilithic Eunotia (Bacillariophyceae, Eunotiaceae) from the Chapada Diamantina region, Northeast Brazil
    Phytotaxa, 2014
    Co-Authors: Fernanda Ferrari, Luc Ector, Carlos E. Wetzel, Denise C. Bicudo
    Abstract:

    A new uncommon epilithic diatom, Eunotia relicta sp. nov., is described from a small oligotrophic, acidic stream in the Chapada Diamantina region, northeast Brazil. Eunotia relicta is a typical eunotioid form with a pronounced arch on the dorsal side of the valve mainly in smaller valves. Contrary to most Eunotia species, Eunotia relicta does not possess rectangular frustules in girdle view. Until now, this characteristic was only observed in a few species such as E. charliereimeri Edlund & Brant, E. sarraceniae E.E. Gaiser & J.R. Johansen and E. arcuoides Foged, all of them considered asymmetric along the valve plane. Some interesting morphological features of the new species are broad copulae on the dorsal side, an inconspicuous single conical spine on the valve face near the margin at both poles, and the irregularly thickened interstriae. Moreover, each valve has irregular projections at the dorsal valve face margin/mantle juncture and up to three rimoportulae per valve located on the mantle. These features associated with the distinct valve outline set it apart from E. charliereimeri, E. sarraceniae and E. arcuoides, which have no spines, smooth valve faces and 1–2 rimoportulae per valve.

  • uma nova especie de Eunotia ehrenberg bacillariophyceae da chapada diamantina nordeste do brasil
    XIV Congresso Brasileiro de Ficologia, 2012
    Co-Authors: Fernanda Ferrari, Denise C. Bicudo, Carlos E. Wetzel, Luc Ector
    Abstract:

    O presente trabalho apresenta uma analise morfologica de uma especie epilitica e pouco comum de Eunotia Ehrenberg, encontrada no nordeste do Brasil. As amostras foram coletadas em um riacho pequeno e oligotrofico, localizado na regiao da Chapada Diamantina. Eunotia sp. possui forma tipicamente eunotioide e contorno valvar similar a um “chapeu de pirata”, o que a torna semelhante a alguns taxons do complexo E . monodon Ehrenberg, tais como E . inspectabilis Metzeltin & Lange-Bertalot, E . noerpeliana Metzeltin & Lange-Bertalot and E . crassula Metzeltin & Lange-Bertalot. Apresenta, contudo, margem dorsal fortemente convexa e inclinada, chegando a formar um arco pronunciado nas valvas menores, caracteristica nao observada nas especies anteriormente citadas. Alem disso, Eunotia sp. possui bandas do cingulo mais largas do lado dorsal da valva em relacao ao ventral, o que confere simetria ‘ amphoroid’ a frustula. Esta caracteristica peculiar foi ate o momento somente observada dentro do genero em E . charliereimeri Edlund & Brant e E . sarraceniae E. E. gaiser & J. R. Johansen, especies registradas na America do Norte. A nova especie brasileira apresenta, ainda, um espinho conico isolado na face valvar e proximo as extremidades, costelas espessadas e irregularmente distribuidas entre grupos de estrias, projecoes irregulares na juncao margem/manto valvar, e tres rimoportulas por valva, situadas inteiramente no manto. Estas caracteristicas, associadas ao contorno valvar, tornam Eunotia sp. muito distinta de E . charliereimeri Edlund & Brant e E . sarraceniae E. E. gaiser & J. R. Johansen, as quais nao possuem espinhos, tem face valvar lisa e duas rimoportulas por valva, uma em cada extremidade. Entre os taxons de Eunotiophycidae com simetria ‘ amphoroid ’, Eunotia sp. seria melhor posicionada no genero Eunotia devido a ausencia de caracteres tipicos de Amphorotia D.M. Williams & G. Reid e Eunophora W. Vyverman, K. Sabbe & D. G. Mann nos especimes observados.

Wim Vyverman - One of the best experts on this subject based on the ideXlab platform.

  • Alignment_partial_rbcL_Eunotia
    2016
    Co-Authors: Pieter Vanormelingen, David G. Mann, Katharine M. Evans, Stacey Lance, Ann-eline Debeer, Sofie D'hondt, Tine Verstraete, Luc De Meester, Wim Vyverman
    Abstract:

    Partial rbcL sequences of Eunotia bilunaris "robust" strains used for phylogeography of the species in Western Europe (Fig. 2)

  • MLG_data_Ebilunaris_robust
    2016
    Co-Authors: Pieter Vanormelingen, David G. Mann, Katharine M. Evans, Stacey Lance, Ann-eline Debeer, Sofie D'hondt, Tine Verstraete, Luc De Meester, Wim Vyverman
    Abstract:

    Microsatellite allelic composition of Eunotia bilunaris "robust" strains

  • Isolation_by_distance
    2016
    Co-Authors: Pieter Vanormelingen, David G. Mann, Katharine M. Evans, Stacey Lance, Ann-eline Debeer, Sofie D'hondt, Tine Verstraete, Luc De Meester, Wim Vyverman
    Abstract:

    Matrices of pairwise standardized Fst values and (log-transformed) geographic distances between sampling locations of Eunotia bilunaris "robust" and Sellaphora capitata respectively, for assessment of isolation-by-distance patterns (Fig. 3)

  • Genotypic diversity and differentiation among populations of two benthic freshwater diatoms as revealed by microsatellites
    Molecular ecology, 2015
    Co-Authors: Pieter Vanormelingen, David G. Mann, Ann-eline Debeer, Sofie D'hondt, Tine Verstraete, Luc De Meester, Katharine Evans, Stacey L. Lance, Wim Vyverman
    Abstract:

    Given their large population sizes and presumed high dispersal capacity, protists are expected to exhibit homogeneous population structure over large spatial scales. On the other hand, the fragmented and short-lived nature of the lentic freshwater habitats that many protists inhabit promotes strong population differentiation. We used microsatellites in two benthic freshwater diatoms, Eunotia bilunaris ‘robust’ and Sellaphora capitata, sampled from within a pond and connected ponds, through isolated ponds from the same region to western Europe to determine the spatial scale at which differentiation appears. Because periods of low genotypic diversity contribute to population differentiation, we also assessed genotypic diversity. While genotypic diversity was very high to maximal in most samples of both species, some had a markedly lower diversity, with up to half (Eunotia) and over 90% (Sellaphora) of the strains having the same multilocus genotype. Population differentiation showed an isolation-by-distance pattern with very low standardized FST values between samples from the same or connected ponds but high values between isolated ponds, even when situated in the same region. Partial rbcL sequences in Eunotia were consistent with this pattern as isolated ponds in the same region could differ widely in haplotype composition. Populations identified by Structure corresponded to the source ponds, confirming that ‘pond’ is the main factor structuring these populations. We conclude that freshwater benthic diatom populations are highly fragmented on a regional scale, reflecting either less dispersal than is often assumed or reduced establishment success of immigrants, so that dispersal does not translate into gene flow.

  • Congruence of morphological, reproductive and ITS rDNA sequence data in some Australasian Eunotia bilunaris (Bacillariophyta)
    European Journal of Phycology, 2007
    Co-Authors: Pieter Vanormelingen, Victor A. Chepurnov, David G. Mann, Sylvie Cousin, Wim Vyverman
    Abstract:

    Clones identified as Eunotia bilunaris were isolated from two freshwater habitats in New Zealand and one in Tasmania. Experimental studies of sexual reproduction showed that the mating system was strictly heterothallic. All clones were morphologically similar and, in mixtures of compatible clones, were able to produce a viable F1, regardless of geographical origin. There was nevertheless some geographically related variation in ITS rDNA sequences, suggesting that dispersal and concerted evolution are unable to prevent allopatric divergence. Isolates from two of the three localities also showed significant ITS polymorphisms. Auxosporulation followed a similar pattern to that in other Eunotia species, being isogamous with a single functional gamete per gametangium; plasmogamy was effected via two fusing papillae. Details of auxospore structure, initial cell size, and vegetative valve metrics (width, striation densities) show that conspecificity with a recently studied European E. bilunaris is doubtful. The ...

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