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| Titel |
Modelling an alkenone-like proxy record in the NW African upwelling |
| VerfasserIn |
X. Giraud |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 3, no. 3 ; Nr. 3, no. 3 (2006-06-21), S.251-269 |
| Datensatznummer |
250001057
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| Publikation (Nr.) |
 copernicus.org/bg-3-251-2006.pdf |
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| Zusammenfassung |
| A regional biogeochemical model is applied to the NW African coastal
upwelling between 19° N and 27° N to investigate
how a water temperature proxy, alkenones, are produced at the sea
surface and recorded in the slope sediments. The biogeochemical
model has two phytoplankton groups: an alkenone producer group,
considered to be coccolithophores, and a group comprising other
phytoplankton. The Regional Ocean Modelling System (ROMS) is used to
simulate the ocean circulation and takes advantage of the Adaptive
Grid Refinement in Fortran (AGRIF) package to set up an embedded
griding system. In the simulations the alkenone temperature records
in the sediments are between 1.1 and 2.3°C colder than the
annual mean SSTs. Despite the seasonality of the coccolithophore
production, this temperature difference is not mainly due to a
seasonal bias, nor to the lateral advection of phytoplankton and
phytodetritus seaward from the cold near-shore waters, but to the
production depth of the coccolithophores. If coretop alkenone
temperatures are effectively recording the annual mean SSTs, the
amount of alkenone produced must vary among the coccolithophores in
the water column and depend on physiological factors (e.g. growth
rate, nutrient stress). |
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