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| Titel |
The impact on atmospheric CO2 of iron fertilization induced changes in the ocean's biological pump |
| VerfasserIn |
X. Jin, N. Gruber, H. Frenzel, S. C. Doney, J. C. McWilliams |
| 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 ; 5, no. 2 ; Nr. 5, no. 2 (2008-03-18), S.385-406 |
| Datensatznummer |
250002373
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| Publikation (Nr.) |
 copernicus.org/bg-5-385-2008.pdf |
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| Zusammenfassung |
| Using numerical simulations, we quantify the impact of changes in
the ocean's biological pump on the air-sea balance of CO2 by
fertilizing a small surface patch in the high-nutrient,
low-chlorophyll region of the eastern tropical Pacific with iron.
Decade-long fertilization experiments are conducted in a
basin-scale, eddy-permitting coupled
physical/biogeochemical/ecological model.
In contrast to previous studies, we find that most
of the dissolved inorganic carbon (DIC) removed from the
euphotic zone by the enhanced biological export is replaced by
uptake of CO2 from the atmosphere. Atmospheric uptake
efficiencies, the ratio of the perturbation in air-sea CO2 flux
to the perturbation in export flux across 100 m, integrated over 10
years, are 0.75 to 0.93 in our patch size-scale experiments. The
atmospheric uptake efficiency is insensitive to the duration of the
experiment. The primary factor controlling the atmospheric uptake
efficiency is the vertical distribution of the enhanced biological
production and export. Iron fertilization at the surface tends to induce
production anomalies primarily near the surface, leading to high
efficiencies. In contrast, mechanisms that induce deep production
anomalies (e.g. altered light availability) tend to have a low
uptake efficiency, since most of the removed DIC is
replaced by lateral and vertical transport and mixing. Despite high
atmospheric uptake efficiencies, patch-scale iron fertilization of
the ocean's biological pump tends to remove little CO2 from the
atmosphere over the decadal timescale considered here. |
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