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| Titel |
High-resolution analysis of trace elements in encrusting coralline red algae by laser ablation ICP-MS |
| VerfasserIn |
S. Hetzinger, J. Halfar, T. Zack, K. Simon, A. Kronz, W. Adey, P. A. Lebednik, R. S. Steneck, B. R. Schöne |
| Konferenz |
EGU General Assembly 2009
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 11 (2009) |
| Datensatznummer |
250022366
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| Zusammenfassung |
| Coralline red algae constitute an ideal biogenic marine climate recorder owing to their
common occurrence in mid- to high latitude oceans and their continuous growth. Encrusting
coralline red algae have great potential as paleoclimate archives because they deposit
spatially fixed annual growth increments in a high Mg-calcite skeleton and can reach ages
of up to several hundred years. Here we present high-resolution Laser Ablation
Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) trace elemental
analyses (Mg, Sr, Ba, U) from several coralline red algal specimens of the genus
Clathromorphum, collected from the North Atlantic and North Pacific Oceans, that
display average growth rates of around 300μm/year. Elemental ratios (Mg/Ca, Sr/Ca,
Ba/Ca, U/Ca) were measured in sub-monthly resolution for up to 65-year long
segments of coralline red algal growth. Several overlapping transects were analyzed in
order to assess the robustness of the proxy data. The reproducibility is excellent and
LA-ICP-MS measured Mg/Ca ratios were validated by comparison to electron
microprobe data. In addition, data accuracy was tested by comparison to solution
ICP-OES data from a bulk sample manually removed parallel to the laser ablation and
electron microprobe transects. In particular, algal Mg/Ca ratios show a high degree of
correlation with local seawater temperature on different timescales, providing further
evidence for the temperature dependency of algal Mg/Ca variations and their use
as a valuable paleothermometer. Hence, this study demonstrates the feasibility of
extracting high-resolution geochemical signals from encrusting coralline red algae
(such as Clathromorphum sp.) using laser ablation ICP-MS. This analysis technique
allows rapid continuous sampling of the algal surface with unprecedented resolution
and provides a valuable tool for future analysis of algal-derived environmental
records. |
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