GLORIA

GEOMAR Library Ocean Research Information Access

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • 2020-2024  (3)
  • 1
    Publication Date: 2023-07-06
    Description: This study presents culture experiments of the cold water species Neogloboquadrina pachyderma (sinistral) and provides new insights into the incorporation of elements in foraminiferal calcite of common and newly established proxies for paleoenvironmental applications (shell Mg/Ca, Sr/Ca and Na/Ca). Specimens were collected from sea ice during the austral winter in the Antarctic Weddell Sea and subsequently cultured at different salinities and a constant temperature. Incorporation of the fluorescent dye calcein showed new chamber formation in the culture at salinities of 30, 31, and 69. Cultured foraminifers at salinities of 46 to 83 only revealed chamber wall thickening, indicated by the fluorescence of the whole shell. Signs of reproduction and the associated gametogenic calcite were not observed in any of the culture experiments. Trace element analyses were performed using an electron microprobe, which revealed increased shell Mg/Ca, Sr/Ca, and Na/Ca values at higher salinities, with Mg/Ca showing the lowest sensitivity to salinity changes. This study enhances the knowledge about unusually high element concentrations in foraminifera shells from high latitudes. Neogloboquadrina pachyderma appears to be able to calcify in the Antarctic sea ice within brine channels, which have low temperatures and exceptionally high salinities due to ongoing sea ice formation.
    Description: Deutsche Forschungsgemeinschaft http://dx.doi.org/10.13039/501100001659
    Description: GEOMAR Helmholtz-Zentrum für Ozeanforschung Kiel http://dx.doi.org/10.13039/501100003153
    Keywords: ddc:561 ; foraminifera ; chamber calcification ; salinity effects ; experiments ; paleooceanographic reconstructions
    Language: English
    Type: doc-type:article
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 2
    Publication Date: 2023-02-08
    Description: The estimation of past seawater salinities in combination with temperatures allows to reconstruct past oceanic conditions and to understand processes related to climate change. Seawater salinity is thereby one of the most important parameters for paleo-reconstructions. For example, changes in sea surface salinity indirectly reflect variations in the hydrological cycle, or changes in density fluxes of water masses, which in turn allows reconstructing ocean circulations (e.g., thermohaline circulation). In this respect, a recent culture study by Wit et al. (2013) proposed a significant positive relationship between salinity and the incorporation of sodium/calcium (Na/Ca) into benthic foraminifer calcite.Based on these observations and the steady search for a quantitative salinity proxy, our study presents Na/Ca ratios of planktonic foraminifers as a new promising and direct paleosalinity proxy, with the high potential to complement and improve existing approaches (e.g., paired shell Mg/Ca and δ18O). The implementation of Na/Ca as a new proxy should address and constrain internal and external controls of element incorporation into foraminiferal calcite. Accordingly, this proxy assessment study comprises three approaches. First, Na/Ca studies on planktonic foraminifers cultured under controlled laboratory conditions; second, the analysis of Na/Ca incorporation in living planktonic species from plankton tows; third, the evaluation of the Na/Ca preservation in fossil foraminifers in comparison to living specimens. All these approaches support the reliability for paleo-applications. (...)
    Type: Thesis , NonPeerReviewed
    Format: text
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 3
    Publication Date: 2024-02-07
    Description: This study presents culture experiments of the cold water species Neogloboquadrina pachyderma (sinistral) and provides new insights into the incorporation of elements in foraminiferal calcite of common and newly established proxies for paleoenvironmental applications (shell Mg/Ca, Sr/Ca and Na/Ca). Specimens were collected from sea ice during the austral winter in the Antarctic Weddell Sea and subsequently cultured at different salinities and a constant temperature. Incorporation of the fluorescent dye calcein showed new chamber formation in the culture at salinities of 30, 31, and 69. Cultured foraminifers at salinities of 46 to 83 only revealed chamber wall thickening, indicated by the fluorescence of the whole shell. Signs of reproduction and the associated gametogenic calcite were not observed in any of the culture experiments. Trace element analyses were performed using an electron microprobe, which revealed increased shell Mg/Ca, Sr/Ca, and Na/Ca values at higher salinities, with Mg/Ca showing the lowest sensitivity to salinity changes. This study enhances the knowledge about unusually high element concentrations in foraminifera shells from high latitudes. Neogloboquadrina pachyderma appears to be able to calcify in the Antarctic sea ice within brine channels, which have low temperatures and exceptionally high salinities due to ongoing sea ice formation.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...