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| Titel |
Coral Cd/Ca and Mn/Ca records of ENSO variability in the Gulf of California |
| VerfasserIn |
J. D. Carriquiry, J. A. Villaescusa |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1814-9324
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| Digitales Dokument |
URL |
| Erschienen |
In: Climate of the Past ; 6, no. 3 ; Nr. 6, no. 3 (2010-06-28), S.401-410 |
| Datensatznummer |
250003550
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| Publikation (Nr.) |
 copernicus.org/cp-6-401-2010.pdf |
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| Zusammenfassung |
| We analyzed the trace element ratios Cd/Ca and Mn/Ca in three coral colonies
(Porites panamensis (1967–1989), Pavona clivosa (1967–1989) and Pavona gigantea (1979–1989)) from Cabo Pulmo reef,
Southern Gulf of California, Mexico, to assess the oceanographic changes
caused by El Niño – Southern Oscillation (ENSO) events in the Eastern
Tropical North Pacific (ETNP). Interannual variations in the coral Cd/Ca and
Mn/Ca ratios showed clear evidence that incorporation of Cd and Mn in the
coral skeleton was influenced by ENSO conditions, but the response for each
metal was controlled by different processes. The Mn/Ca ratios were
significantly higher during ENSO years (p<0.05) relative to non-ENSO years
for the three species of coral. In contrast, the Cd/Ca was systematically
lower during ENSO years, but the difference was significant (p<0.05) only
in Pavona gigantea. A decrease in the incorporation of Cd and a marked increase in Mn
indicated strongly reduced vertical mixing in the Gulf of California during
the mature phase of El Niño. The oceanic warming during El Niño
events produces a relaxation of upwelling and a stabilization of the
thermocline, which may act as a physical barrier limiting the transport of
Cd from deeper waters into the surface layer. In turn, this oceanic
condition can increase the residence time of particulate-Mn in surface
waters, allowing an increase in the photo-reduction of particulate-Mn and
the release of available Mn into the dissolved phase. These results support
the use of Mn/Ca and Cd/Ca ratios in biogenic carbonates as tracers of
increases in ocean stratification and trade wind weakening and/or collapse
in the ETNP during ENSO episodes. |
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