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  • Foraminifera  (4)
  • American Geophysical Union  (4)
  • 1
    Publication Date: 2022-05-25
    Description: Author Posting. © American Geophysical Union, 2010. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Paleoceanography 25 (2010): PA2211, doi:10.1029/2009PA001846.
    Description: Carbon isotopes of foraminiferal tests provide a widely used proxy for past oceanographic environmental conditions. This proxy can be calibrated using live specimens, which are reliably identified with observations of cell ultrastructure. Observations of ultrastructures can also be used for studies of biological characteristics such as diet and presence of symbionts. Combining biological and isotopic studies on individual foraminifera could provide novel information, but standard isotopic methods destroy ultrastructures by desiccating specimens and observations of ultrastructure require removal of carbonate tests, preventing isotope measurements. The approach described here preserves cellular ultrastructure during isotopic analyses by keeping the foraminifera in an aqueous buffer (Phosphate Buffered Saline (PBS)). The technique was developed and standardized with 36 aliquots of NBS-19 standard of similar weight to foraminiferal tests (5 to 123 μg). Standard errors ranged from ± 0.06 to ± 0.85‰ and were caused by CO2 contaminants dissolved in the PBS. The technique was used to measure δ13C values of 96 foraminifera, 10 of which do not precipitate carbonate tests. Calcareous foraminiferal tests had corrected carbon isotope ratios of −8.5 to +3.2‰. This new technique allows comparisons of isotopic compositions of tests made by foraminifera known to be alive at the time of collection with their biological characteristics such as prey composition and presence or absence of putative symbionts. The approach may be applied to additional biomineralizing organisms such as planktonic foraminifera, pteropods, corals, and coccolithophores to elucidate certain biological controls on their paleoceanographic proxy signatures.
    Description: Support was provided by NSF grants OCE‐0550396 (to J.B.M.), OCE‐0551001 (to J.M.B.), and OCE‐ 0550401 (to A.E.R.).
    Keywords: Foraminifera ; Ultrastructure ; Carbon isotopes
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Format: application/pdf
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  • 2
    Publication Date: 2022-05-25
    Description: Author Posting. © American Geophysical Union, 2006. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research 111 (2006): G03002, doi:10.1029/2005JG000158.
    Description: Our current understanding of paleoecology and paleoceanography is largely based on the superb Phanerozoic fossil record of foraminiferan protists. The early history of the group is unresolved, however, because basal foraminiferans (allogromiids) are unmineralized and thus fossilize poorly. Molecular-clock studies date foraminiferal origins to the Neoproterozoic, but the deep sea – one of Earth’s most extensive habitats and presently a significant fraction of basal foraminiferal diversity— was probably anoxic at that time and, until now, anaerobic allogromiids were unknown. Molecular, cell and ecological analyses reveal the presence of a previously unknown allogromiid inhabiting anoxic, sulfidic deep-sea sediments (Santa Barbara Basin, California, USA). The fact that the new foraminifer harbors prokaryotic endobionts implicates symbiogenesis as a driving force in early foraminiferal diversification.
    Description: The Wadsworth Center’s Electron Microscopy, Biochemistry, and Molecular Genetics Core facilities, as well as its National Biotechnology Resource for the Visualization of Biological Complexity (supported by a NIH BRTP/NCRR grant) are gratefully acknowledged. Funded by NASA Exobiology NRA-01-01-EXB-057 (to J.M.B.); W. Storrs Cole Memorial Research Award (Geological Society of America, to J.M.B.); NSF DEB0445181 (to S.S.B.).
    Keywords: Foraminifera ; Santa Barbara Basin ; Symbiosis
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Format: application/pdf
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  • 3
    Publication Date: 2022-10-26
    Description: Author Posting. © American Geophysical Union, 2019. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research-Biogeosciences 124 (2019): 2823-2850, doi:10.1029/2019JG005113.
    Description: Microscopy techniques have been widely applied to observe cellular ultrastructure. Most of these techniques, such as transmission electron microscopy, produce high‐resolution images, but they may require extensive preparation, hampering their application for in vivo examination. Other approaches, such as fluorescent and fluorogenic probes, can be applied not only to fixed specimens but also to living cells when the probes are nontoxic. Fluorescence‐based methods, which are generally relatively easy to use, allow visual and (semi)quantitative studies of the ultrastructural organization and processes of the cell under natural as well as manipulated conditions. To date, there are relatively few published studies on the nearly ubiquitous marine protistan group Foraminifera that have used fluorescent and fluorogenic probes, despite their huge potential. The aim of the present contribution is to document the feasible application of a wide array of these probes to foraminiferal biology. More specifically, we applied fluorescence‐based probes to study esterase activity, cell viability, calcium signaling, pH variation, reactive oxygen species, neutral and polar lipids, lipid droplets, cytoskeleton structures, Golgi complex, acidic vesicles, nuclei, and mitochondria in selected foraminiferal species.
    Description: The authors are very grateful to the Editor‐in‐Chief Miguel Goni and two anonymous reviewers for their thoughtful and valuable comments that have greatly improved the paper. Markus Raitzsch and Karina Kaczmarek from the AWI, Jakub Kordas from the ZOO Wrocław sp. z o. o. (Poland), and Max Janse from The Royal Burgers' Zoo (Arnhem, the Netherlands) are gratefully acknowledged. The authors declare that no competing interests exist. All the data are included within the paper or the supporting information accompanying it. The research for this paper was partially supported by the Ministero dell'Istruzione, dell'Università e della Ricerca (PRIN 2010‐2011 protocollo 2010RMTLYR) to R.C., the Japan Society for the Promotion of Science KAKENHI Grant (Numbers: JP18H06074, JP17H02978, JP19H02009, JP19H03045) to T.T. and Y.N., the WHOI Investment in Science Program to J.M.B, the Polish National Science Center (Grant DEC‐2015/19/B/ST10/01944) J.T. and J.G. and the Kuwait Foundation for the Advancement of Sciences (EM084C) to E.A‐E.
    Description: 2020-02-22
    Keywords: Protist ; Organelles ; Confocal laser scanning microscopy ; Probes ; Foraminifera
    Repository Name: Woods Hole Open Access Server
    Type: Article
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  • 4
    Publication Date: 2022-05-26
    Description: Author Posting. © American Geophysical Union, 2010. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Paleoceanography 25 (2010): PA4206, doi:10.1029/2010PA001930.
    Description: Numerous previous studies show disequilibrium between stable carbon isotope ratios of foraminiferal calcite and pore water dissolved inorganic carbon in hydrocarbon seeps, calling into question the utility of this widely used paleoceanographic tracer as a proxy. We use a recently developed method to compare stable carbon isotope ratios of foraminiferal carbonate with cell ultrastructural observations from individual benthic foraminifera from seep (under chemosynthetic bivalves) and nonseep habitats in Monterey Bay, California, to better understand control(s) of benthic foraminiferal carbon isotope ratios. Two attributes previously proposed to cause the isotopic offsets are diet and symbionts. Ultrastructural analysis shows that positive staining with Rose Bengal indicates presence of foraminiferal cytoplasm, bacterial biomass, or a combination of both and, thus, is not an unequivocal indicator of viability. We also show for the first time that some living seep foraminifera have endobionts. Results from our unique, yet limited, data set are consistent with suggestions that, in our sites, several foraminiferal species collected from seep clam beds may not survive there, diet and symbiont presence do not appear to be major contributors to disequilibrium, little calcification of seep-tolerant foraminiferal species occurs while seep conditions prevail, and microscale variability in habitats could influence δ13C of benthic foraminiferal carbonate. Results further suggest that our knowledge of benthic foraminiferal ecology and biomineralization, especially in extreme habitats such as seeps, must be bolstered before we fully understand the fidelity of paleoenvironmental records derived from benthic foraminiferal test δ13C data.
    Description: This collaborative research was supported by NSF Marine Geology and Geophysics Program (OCE‐0551001 (to J.M.B), OCE‐0550396 (to J.B.M.), and OCE‐0550401 (to A.E.R.)).
    Keywords: Clam Flats ; Monterey Bay ; Carbon isotopes ; Disequilibrium ; Foraminifera ; Cold seep
    Repository Name: Woods Hole Open Access Server
    Type: Article
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    Format: image/tiff
    Format: text/plain
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