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  • PANGAEA  (14)
  • Springer  (4)
  • Bottrop : Hochschule Ruhr West  (1)
  • Oxford Univ. Press  (1)
Schlagwörter
Sprache
Erscheinungszeitraum
  • 1
    Schlagwort(e): Forschungsbericht ; Verwaltung ; Open educational Resources ; Wissensmanagement
    Materialart: Online-Ressource
    Seiten: 1 Online-Ressource (152 Seiten, 4,78 MB) , Illustrationen, Diagramme
    Sprache: Deutsch
    Anmerkung: Förderkennzeichen BMBF 01PO16017A. - Verbund-Nummer 01176259 , Unterschiede zwischen dem gedruckten Dokument und der elektronischen Ressource können nicht ausgeschlossen werden , Sprache der Zusammenfassung: Deutsch, Englisch
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 2
    ISSN: 1432-1432
    Schlagwort(e): Foraminifera ; Sequence dissimilarity ; LSU rRNA gene ; Phylogeny
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract An unusually high divergence was observed in the ribosomal RNA genes of a free-living population of foraminifera belonging to the genusAmmonia. The sequences of a large-subunit (LSU) rDNA expansion segment D1 and flanking regions were obtained from 20 specimens namedAmmonia sp. 1 andAmmonia sp. 2. The sequence divergence between the two species averages 14%. Within each species it ranges from 0.2% to 7.1% inAmmonia sp. 1 and from 0.7% to 2.3% inAmmonia sp. 2. We did not find two specimens having identical sequences. Moreover, in opposition to the generally acaepted view, rDNA sequence variations were also found within a single individual. The variations among several rDNA copies in a single specimen ofAmmonia may reach up to 4.9%. Most of the observed variations result from multiplication of CA or TA serial repeats occurring in two particularly variable regions. For single base changes, C-T transitions are most frequently observed. We discuss the evolution of expansion segments and their use for phylogenetic studies.
    Materialart: Digitale Medien
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 3
    ISSN: 1432-1432
    Schlagwort(e): Key words: Planktonic foraminifera — Molecular phylogenetics — Rates of substitution — Ribosomal DNA
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract. Planktonic foraminifera are marine protists, whose calcareous shells form oceanic sediments and are widely used for stratigraphic and paleoenvironmental analyses. The fossil record of planktonic foraminifera is compared here to their molecular phylogeny inferred from ribosomal DNA sequences. Eighteen partial SSU rDNA sequences from species representing all modern planktonic families (Globigerinidae, Hastigerinidae, Globorotaliidae, Candeinidae) were obtained and compared to seven sequences representing the major groups of benthic foraminifera. The phylogenetic analyses indicate a polyphyletic origin for the planktonic foraminifera. The Candeinidae, the Globorotaliidae, and the clade Globigerinidae + Hastigerinidae seem to have originated independently, at different epochs in the evolution of foraminifera. Inference of their relationships, however, is limited by substitution rates of heterogeneity. Rates of SSU rDNA evolution vary from 4.0 × 10−9 substitutions/site/year in the Globigerinidae to less than 1.0 × 10−9 substitutions/site/year in the Globorotaliidae. These variations may be related to different levels of adaptation to the planktonic mode of life. A clock-like evolution is observed among the Globigerinidae, for which molecular and paleontological data are congruent. Phylogeny of the Globorotaliidae is clearly biased by rapid rates of substitution in two species (G. truncatulinoides and G. menardii). Our study reveals differences in absolute rates of evolution at all taxonomic levels in planktonic foraminifera and demonstrates their effect on phylogenetic reconstructions.
    Materialart: Digitale Medien
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 4
    ISSN: 1573-5192
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract The taxonomic history of the species of Plagiorchis Lühe, 1899 occurring in European bats has been very confused because of high morphological similarity between different forms/species and the inadequate initial description of P. vespertilionis(Müller, 1780). As morphological data alone have not provided enough convincing arguments to solve the problem, the sequences from the nuclear rDNA ITS region (ITS1, 5.8S and ITS2) of three species of the P. vespertilionis group (P. vespertilionis, P. muelleri Tkach & Sharpilo, 1990 and P. koreanus Ogata, 1938) occurring in European bats were used to test the validity of these species and evaluate some of the morphological characters used for the species differentiation within this group. P. elegans from birds was used as the outgroup in the analysis. All three ingroup species were clearly distinguishable using ITS sequences. Among them, P. koreanus occupied a basal position, while P. vespertilionis and P. muelleri appeared as a cluster of two closely related, derived species. ITS sequences of the specimens obtained from different hosts and/or geographical areas did not exhibit any intraspecific variability. Morphological study of the material in collections revealed characters which enable the species of Plagiorchis from bats in Europe to be distinguished. Taking into account that the type-material of P. vespertilionis, described during the 18th Century, has been lost, for nomenclatural stability, a neotype is established and described. An amended description of the type-material of P. muelleri and keys for the determination of Plagiorchis spp. from European bats are presented.
    Materialart: Digitale Medien
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 5
    facet.materialart.
    Unbekannt
    PANGAEA
    In:  Supplement to: Kucera, Michal; Silye, Lóránd; Weiner, Agnes K M; Darling, Kate F; Lübben, Birgit; Holzmann, Maria; Pawlowski, Jan; Schönfeld, Joachim; Morard, Raphael (2017): Caught in the act: Anatomy of an ongoing benthic-planktonic transition in a marine protist. Journal of Plankton Research, 39 (3), 436-449, https://doi.org/10.1093/plankt/fbx018
    Publikationsdatum: 2024-07-19
    Beschreibung: The transition from benthos to plankton requires multiple adaptations, yet so far it remains unclear how these are acquired in the course of the transition. To investigate this process, we analyzed the genetic diversity and distribution patterns of a group of foraminifera of the genus Bolivina with a tychopelagic mode of life (same species occurring both in benthos and plankton). We assembled a global sequence dataset for this group from single-cell DNA extractions and occurrences in metabarcodes from pelagic environmental samples. The pelagic sequences all cluster within a single monophyletic clade within Bolivina. This clade harbors three distinct genetic lineages, which are associated with incipient morphological differentiation. All lineages occur in plankton and benthos, but only one lineage shows no limit to offshore dispersal and has been shown to grow in the plankton. These observations indicate that the emergence of buoyancy regulation within the clade preceded the evolution of pelagic feeding and that the evolution of both traits was not channeled into a full transition into the plankton. We infer that in foraminifera, colonization of the planktonic niche may occur by sequential cooptation of independently acquired traits, with holoplanktonic species being recruited from tychopelagic ancestors.
    Schlagwort(e): Center for Marine Environmental Sciences; MARUM
    Materialart: dataset publication series
    Format: application/zip, 4 datasets
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  • 6
    facet.materialart.
    Unbekannt
    PANGAEA
    In:  Supplement to: Brandt, Angelika; Gooday, Andrew J; Brandão, Simone N; Brix, Saskia; Brökeland, Wiebke; Cedhagen, Tomas; Choudhury, Madhumita; Cornelius, Nils; Danis, Bruno; De Mesel, Ilse; Diaz, Robert; Gillan, David C; Ebbe, Brigitte; Howe, John; Janussen, Dorte; Kaiser, Stefanie; Linse, Katrin; Malyutina, Marina; Pawlowski, Jan; Raupach, Michael R; Vanreusel, Ann (2007): First insights into the biodiversity and biogeography of the Southern Ocean deep sea. Nature, 447(7142), 307-311, https://doi.org/10.1038/nature05827
    Publikationsdatum: 2024-07-19
    Beschreibung: Shallow marine benthic communities around Antarctica show high levels of endemism, gigantism, slow growth, longevity and late maturity, as well as adaptive radiations that have generated considerable biodiversity in some taxa1. The deeper parts of the Southern Ocean exhibit some unique environmental features, including a very deep continental shelf2 and a weakly stratified water column, and are the source for much of the deep water in the world ocean. These features suggest that deep-sea faunas around the Antarctic may be related both to adjacent shelf communities and to those in other oceans. Unlike shallow-water Antarctic benthic communities, however, little is known about life in this vast deep-sea region2, 3. Here, we report new data from recent sampling expeditions in the deep Weddell Sea and adjacent areas (748-6,348 m water depth) that reveal high levels of new biodiversity; for example, 674 isopods species, of which 585 were new to science. Bathymetric and biogeographic trends varied between taxa. In groups such as the isopods and polychaetes, slope assemblages included species that have invaded from the shelf. In other taxa, the shelf and slope assemblages were more distinct. Abyssal faunas tended to have stronger links to other oceans, particularly the Atlantic, but mainly in taxa with good dispersal capabilities, such as the Foraminifera. The isopods, ostracods and nematodes, which are poor dispersers, include many species currently known only from the Southern Ocean. Our findings challenge suggestions that deep-sea diversity is depressed in the Southern Ocean and provide a basis for exploring the evolutionary significance of the varied biogeographic patterns observed in this remote environment.
    Schlagwort(e): AWI; Priority Programme 1158 Antarctic Research with Comparable Investigations in Arctic Sea Ice Areas; SPP1158
    Materialart: dataset publication series
    Format: application/zip, 2 datasets
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  • 7
    Publikationsdatum: 2024-07-19
    Beschreibung: Environmental DNA (eDNA) metabarcoding of marine sediments has revealed large amounts of sequences assigned to planktonic taxa. How this planktonic eDNA is delivered on the seafloor and preserved in the sediment is not well understood. We address these questions by comparing metabarcoding and microfossil foraminifera assemblages in sediment cores taken off Newfoundland across a strong ecological gradient. We detected planktonic foraminifera eDNA down to 30 cm and observed that the planktonic/benthic amplicon ratio changed with depth. The relative proportion of planktonic foraminiferal amplicons remained low from the surface down to 10 cm, likely due to the presence of DNA from living benthic foraminifera. Below 10 cm, the relative proportion of planktonic foraminifera amplicons rocketed, likely reflecting the higher proportion of planktonic eDNA in the DNA burial flux. In addition, the microfossil and metabarcoding assemblages showed a congruent pattern indicating that planktonic foraminifera eDNA is deposited without substantial lateral advection and preserves regional biogeographical patterns, indicating deposition by a similar mechanism as the foraminiferal shells. Our study shows that the planktonic eDNA preserved in marine sediments has the potential to record climatic and biotic changes in the pelagic community with the same spatial and temporal resolution as microfossils.
    Schlagwort(e): Center for Marine Environmental Sciences; Foraminifera; MARUM; metabarcoding; microfossils; North Atlantic; sedimentary ancient DNA
    Materialart: dataset publication series
    Format: application/zip, 3 datasets
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  • 8
    facet.materialart.
    Unbekannt
    PANGAEA
    In:  Supplement to: Majewski, Wojciech; Lecroq, Beatrice; Sinniger, Frederic; Pawlowski, Jan (2007): Monothalamous foraminifera from Admiralty Bay, King George Island, West Antarctica. Polish Polar Research, 28(3), 187-210
    Publikationsdatum: 2024-07-19
    Beschreibung: During the late 2007 austral summer, 20 sediment samples were collected in Admiralty Bay (King George Island, South Shetlands, West Antarctica) from 8 down to 254 m water-depth (mwd). The samples yielded abundant assemblage of monothalamous benthic foraminifera, belonging to at least 40 morphospecies. They constituted the first such collection from Antarctic Peninsula fjords and provided a new insight into this group's diversity and distribution. Among organic-walled taxa, Psammophaga sp., Allogromia cf. crystallifera, and three morphotypes of Gloiogullmia were especially abundant. Agglutinated forms were dominated by Hippocrepinella hirudinea, Psammosphaera spp., Lagenammina spp., and various mudballs. Although, the majority of the morphotypes were known from other high?latitude locations, somewere reported for the first time. Our quantitative data (〉125 µm) showed the greatest differences between monothalamous foraminifera assemblages at shallowest water depths above 50 mwd. The deepest assemblages from between 179 and 254 mwd, were most similar, suggesting uniform near-bottom conditions at ~200 mwd throughout the Admiralty Bay.
    Schlagwort(e): Admiralty_Bay; Allogromia cf. crystallifera; Area; Armorella cf. sphaerica; Armorella sp.; Astrammina rara; Astrammina triangularis; Astrorhiza sp.; Bathysiphon cf. argenteus; Bathysiphon cf. flexilis; Calculated; Calculated after Shannon (1948); Counting 〉125 µm fraction; Crithionina cf. granum; Crithionina sp.; Depth, bathymetric; DEPTH, sediment/rock; Distance; Dominance; Foraminifera, benthic; Foraminifera, benthic dead; Foraminifera, benthic indeterminata; Foraminifera, benthic monothalamous; Fraction; Gloiogullmia sp.; Gromiids; Hippocrepina cf. crassa; Hippocrepinella alba; Hippocrepinella hirudinea; King George Island, Antarctic Peninsula; Lagenammina spp.; LATITUDE; LONGITUDE; Micrometula sp.; MULT; Multiple investigations; Nemogullmia spp.; Number of species; Pelosina aff. sphaeriloculum; Pelosina didera; Phainogullmia cf. aurata; Psammophaga sp.; Psammosphaera spp.; Sample code/label; Sample method; Shannon Diversity Index; Tinogullmia sp.; Vanhoeffenella gaussi
    Materialart: dataset
    Format: text/tab-separated-values, 1015 data points
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  • 9
    Publikationsdatum: 2024-07-19
    Schlagwort(e): Agassiz Trawl; AGT; ANT-XIX/3; ANT-XIX/4; ANT-XXII/3; Date/Time of event; Date/Time of event 2; EBS; Epibenthic sledge; Event label; Expected number of species; Haul length; Latitude of event; Latitude of event 2; Longitude of event; Longitude of event 2; MOOR; Mooring; Polarstern; PS61/041-3; PS61/042-2; PS61/043-8; PS61/046-7; PS61/099-4; PS61/105-7; PS61/114-4; PS61/129-2; PS61/131-3; PS61/132-2; PS61/133-3; PS61/134-3; PS61/135-4; PS61/136-4; PS61/137-4; PS61/138-6; PS61/139-6; PS61/140-8; PS61/141-10; PS61/142-6; PS61/143-1; PS61 ANDEEP 1; PS61 ANDEEP 2; PS67/016-10; PS67/021-7; PS67/059-5; PS67/074-6; PS67/078-9; PS67/080-9; PS67/081-8; PS67/088-8; PS67/094-14; PS67/102-3; PS67/110-8; PS67/121-10; PS67/133-2; PS67/142-5; PS67/150-6; PS67/151-7; PS67/152-6; PS67/153-7; PS67/154-9; PS67 ANDEEP 3; Sample elevation; Scotia Sea, southwest Atlantic; South Atlantic Ocean; Weddell Sea
    Materialart: dataset
    Format: text/tab-separated-values, 120 data points
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  • 10
    Publikationsdatum: 2024-07-19
    Schlagwort(e): Area/locality; Bioturbation; Burrows; Depth, bottom/max; Description; Grain size description; Mounds; Number of stations; Occurrence; Sediment type; Station label; Surface description; Tubes
    Materialart: dataset
    Format: text/tab-separated-values, 270 data points
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