
Open access
Date
2008Type
- Journal Article
ETH Bibliography
yes
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Abstract
The role of nutrients and their impact on primary productivity and the fluctuations in
atmospheric CO2 over glacial-interglacial periods are intensely debated. One of the
cornerstones is the role of phosphorus (P; in the form of phosphate). Suggestions as
to the importance of P evolved from an earlier proposal that P actively participated 5
in changing productivity rates and therefore climate change, to the most recent one
that changes in the glacial ocean inventory of phosphorus were small and not influ-
ential if compared to other macronutrients, such as nitrogen. Using new data coming
from a selection of ODP sites, we illustrate oceanic P sedimentary phases distribu-
tion and reactive P burial fluxes, and we show how P burial fluxes changed over the
10 last glacial-interglacial period. Concentrations of reactive P are generally lower dur-
ing glacial times, while mass accumulation rates (MAR) show higher variability. On
a global scale, glacial burial fluxes of reactive P are lower than those during interglacial
periods by 7–10%, because lack of burial of reactive P on the glacial reduced shelf
was apparently not compensated by burial in other regions of the ocean. Using the
15 calculated changes in P burial, we try to infer 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 20–40% compared to interglacial stages. Variations in the C/P reactive ratios
and in the P sedimentary phases distribution at the investigated sites seem to indicate
20 that at the onset of interglacial stages, shallower sites experienced an increase in re-
active P concentrations. This seems to point to P-richer waters at glacial terminations,
supporting the shelf-nutrient hypothesis and giving phosphorus a role as a potential
player in climate change. Show more
Permanent link
https://doi.org/10.3929/ethz-b-000010813Publication status
publishedJournal / series
Biogeosciences DiscussionsVolume
Pages / Article No.
Publisher
CopernicusOrganisational unit
03427 - Frossard, Emmanuel / Frossard, Emmanuel
Related publications and datasets
Is previous version of: https://doi.org/10.3929/ethz-b-000019410
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