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Titel |
Global prediction of planktic foraminiferal fluxes from hydrographic and productivity data |
VerfasserIn |
S. Žarić, M. Schulz, S. Mulitza |
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. 2 ; Nr. 3, no. 2 (2006-05-04), S.187-207 |
Datensatznummer |
250000888
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Publikation (Nr.) |
copernicus.org/bg-3-187-2006.pdf |
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Zusammenfassung |
Understanding and quantifying the seasonal and spatial distribution of
planktic foraminiferal fluxes reflected in sedimentary assemblages is key to
interpret foraminifera-based proxies in paleoceanography. Towards this goal
we present an empirical model to predict foraminiferal fluxes on a global
scale.
A compilation of planktic foraminiferal flux and export production data from
globally distributed sediment traps together with environmental data of
sea-surface temperature and mixed-layer depth from online databases is used
to calibrate the model that calculates monthly foraminiferal fluxes for the
18 most common species. The calibrated model is then forced with a global
data set of hydrographic and productivity data to predict monthly
foraminiferal fluxes worldwide. The predictive skills of the model are
assessed by comparing the model output with planktic foraminiferal
assemblages from globally distributed surface sediments as well as with
measured foraminiferal fluxes of sediment traps not included in the
calibration data set.
Many general distribution patterns of foraminiferal species recognized from
the model output compare favorably with observations from coretops or
sediment traps, even though the model still produces problematic results in
some places. Among others, meridional gradients in species richness and
diversity, increased relative abundances of Neogloboquadrina pachyderma (dex.) in upwelling areas, and
peak abundances of Globigerinella siphonifera in oligotrophic subtropical gyres show good agreement
between model and coretops. Absolute foraminiferal fluxes are significantly
underestimated in most cases, while seasonal variations can be reproduced
for some species. Interannual differences in foraminiferal fluxes are not
reflected by the model which might partly be due to a lack of actual
environmental data for the calibration and model experiments.
The limited predictive skills of the model suggest that additional
parameters should be considered. Export production should probably be
replaced by a more realistic representation of food availability for
planktic foraminifera. This could be achieved by adding a dynamic component
to the model and linking it to an ecosystem model. |
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