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  • 1
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    Absolute abundances of dinoflagellate cysts in surface sediment samples from four sites: Lycopodium marker-grain method (2009)
    PANGAEA
    In:  Supplement to: Mertens, Kenneth Neil; Verhoeven, Koen; Verleye, Thomas; Louwye, Stephen; Amorim, Ana; Ribeiro, Sofia; Deaf, Amr S; Harding, Ian C; De Schepper, Stijn; González, Catalina; Kodrans-Nsiah, Monika; de Vernal, Anne; Henry, Maryse; Radi, Taoufik; Dybkjaer, Karen; Poulsen, Niels E; Feist-Burkhardt, Susanne; Chitolie, Jonah; Heilmann-Clausen, Claus; Londeix, Laurent; Turon, Jean-Louis; Marret, Fabienne; Matthiessen, Jens; McCarthy, Francine M G; Prasad, Vandana; Pospelova, Vera; Hughes, Jane E Kyffin; Riding, James B; Rochon, André; Sangiorgi, Francesca; Welters, Natasja; Sinclair, Natalie; Thun, Christian; Soliman, Ali; Van Nieuwenhove, Nicolas; Vink, Annemiek; Young, Martin (2009): Determining the absolute abundance of dinoflagellate cysts in recent marine sediments: The Lycopodium marker-grain method put to the test. Review of Palaeobotany and Palynology, Review of Palaeobotany and Palynology, 157(3-4), 238-252, https://doi.org/10.1016/j.revpalbo.2009.05.004
    Details
    Publication Date: 2024-02-02
    Description: Absolute abundances (concentrations) of dinoflagellate cysts are often determined through the addition of Lycopodium clavatum marker-grains as a spike to a sample before palynological processing. An inter-laboratory calibration exercise was set up in order to test the comparability of results obtained in different laboratories, each using its own preparation method. Each of the 23 laboratories received the same amount of homogenized splits of four Quaternary sediment samples. The samples originate from different localities and consisted of a variety of lithologies. Dinoflagellate cysts were extracted and counted, and relative and absolute abundances were calculated. The relative abundances proved to be fairly reproducible, notwithstanding a need for taxonomic calibration. By contrast, excessive loss of Lycopodium spores during sample preparation resulted in non-reproducibility of absolute abundances. Use of oxidation, KOH, warm acids, acetolysis, mesh sizes larger than 15 µm and long ultrasonication (〉 1 min) must be avoided to determine reproducible absolute abundances. The results of this work therefore indicate that the dinoflagellate cyst worker should make a choice between using the proposed standard method which circumvents critical steps, adding Lycopodium tablets at the end of the preparation and using an alternative method.
    Keywords: Benguela; Celtic_Sea; Center for Marine Environmental Sciences; GeoB; Geosciences, University of Bremen; MARUM; MUC; MultiCorer; North_Sea; North Sea; NW_Africa
    Type: Dataset
    Format: application/zip, 4 datasets
    Location Call Number Limitation Availability
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    DATA PANGAEA
  • 2
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    Unknown
    Quantitative estimation of aerobic diagenetic overprint of palaeoproductivity signals (2010)
    Univ. Bremen
    Details
    Publication Date: 2021-03-29
    Description: Organic-walled dinoflagellate cysts, oxidation, degradation, organic matter. - Species-selective aerobic decomposition affects fossil organic-walled dinoflagellate cyst (dinocyst) records and hence dinocyst-based interpretations of primary productivity and oceanographic conditions. However, since the recognition of dinocyst species sensitive and resistant to oxic degradation (S- and R-cysts, respectively) it has become apparent that R-cysts may still serve as reliable productivity and oceanographic conditions proxies. On the other hand S-cysts provide a way to quantify aerobic degradation of organic matter (OM) and past bottom-water O2 concentrations. OM degradation plays a key role in global carbon cycling and is important for global climate change. Therefore dinocysts are a valuable tool for estimating the rate of diagenetic process. Questions concerning species-selective aerobic degradation still remain and will be adressed here. To obtain information on the rate of S-cyst decomposition, the relationship between S-cyst degradation and O2 concentrations, and the aerobic degradation of extinct dinocyst species, a natural exposure experiment has been conducted and studies of both Quaternary and pre-Quaternary material from sediment cores were executed. The exposure experiment was conducted in the natural setting of the Eastern Mediterranean. During a 15 month exposure period to oxic water masses, concentrations of S-cysts (Brigantedinium spp. and Echinidinium granulatum) decreased by 24 to 57%. However, taxa such as Nematosphaeropsis labyrinthus, Echinidinium aculeatum, Operculodinium israelianum and Impagidinium aculeatum demonstrated a slight increase in concentration, indicating resistance to aerobic degradation. These results show that even short-term exposure to oxygen may cause considerable changes in the dinocyst assemblage ...
    Description: thesis
    Keywords: 560 ; VVA 560 ; VXE 000 ; VVA 560 ; VXE 000 ; Aktuopaläontologie ; Protozoa {Paläozoologie}
    Language: English
    Type: monograph , publishedVersion
    Format: 159 S.
    Format: application/pdf
    Location Call Number Limitation Availability
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    CITATION GEO-LEO
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