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| Titel |
Phosphorus burial in the ocean over glacial-interglacial time scales |
| VerfasserIn |
F. Tamburini, K. B. Föllmi |
| 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 ; 6, no. 4 ; Nr. 6, no. 4 (2009-04-02), S.501-513 |
| Datensatznummer |
250003635
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| Publikation (Nr.) |
 copernicus.org/bg-6-501-2009.pdf |
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| Zusammenfassung |
| The role of nutrients, such as phosphorus (P), and their impact on primary
productivity and the fluctuations in atmospheric CO2 over
glacial-interglacial periods are intensely debated. Suggestions as to the
importance of P evolved from an earlier proposal that P actively participated
in changing productivity rates and therefore climate change, to most recent
ones that changes in the glacial ocean inventory of phosphorus were important
but not influential if compared to other macronutrients, such as nitrate.
Using new data coming from a selection of ODP sites, we analyzed the
distribution of oceanic P sedimentary phases and calculate reactive P burial
fluxes, and we show how P burial fluxes changed over the last
glacial-interglacial period at these sites. Concentrations of reactive P are
generally lower during glacial times, while mass accumulation rates (MAR) of
reactive P show higher variability. If we extrapolate for the analyzed sites,
we may assume that in general glacial burial fluxes of reactive P are lower
than those during interglacial periods by about 8%, because the lack of
burial of reactive P on the glacial shelf reduced in size, was apparently not
compensated by burial in other regions of the ocean. Using the calculated
changes in P burial, we evaluate their possible impact on the phosphate
inventory in the world oceans. Using a simple mathematical approach, we find
that these changes alone could have increased the phosphate inventory of
glacial ocean waters by 17–40% compared to interglacial stages. Variations
in the distribution of sedimentary P phases at the investigated sites seem to
indicate that at the onset of interglacial stages, shallower sites
experienced an increase in reactive P concentrations, which seems to point to
P-richer waters at glacial terminations. All these findings would support the
Shelf-Nutrient Hypothesis, which assumes that during glacial low stands
nutrients are transferred from shallow sites to deep sea with possible
feedback on the carbon cycle. |
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