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| Titel |
The iron budget in ocean surface waters in the 20th and 21st centuries: projections by the Community Earth System Model version 1 |
| VerfasserIn |
K. Misumi, K. Lindsay, J. K. Moore, S. C. Doney, F. O. Bryan, D. Tsumune, Y. Yoshida |
| 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 ; 11, no. 1 ; Nr. 11, no. 1 (2014-01-04), S.33-55 |
| Datensatznummer |
250117103
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| Publikation (Nr.) |
 copernicus.org/bg-11-33-2014.pdf |
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| Zusammenfassung |
| We investigated the simulated iron budget in ocean surface waters in the
1990s and 2090s using the Community Earth System Model version 1 and the
Representative Concentration Pathway 8.5 future CO2 emission scenario.
We assumed that exogenous iron inputs did not change during the whole
simulation period; thus, iron budget changes were attributed solely to
changes in ocean circulation and mixing in response to projected global
warming, and the resulting impacts on marine biogeochemistry. The model
simulated the major features of ocean circulation and dissolved iron
distribution for the present climate. Detailed iron budget analysis revealed
that roughly 70% of the iron supplied to surface waters in high-nutrient,
low-chlorophyll (HNLC) regions is contributed by ocean circulation and
mixing processes, but the dominant supply mechanism differed by region:
upwelling in the eastern equatorial Pacific and vertical mixing in the
Southern Ocean. For the 2090s, our model projected an increased iron supply
to HNLC waters, even though enhanced stratification was predicted to reduce
iron entrainment from deeper waters. This unexpected result is attributed
largely to changes in gyre-scale circulations that intensified the advective
supply of iron to HNLC waters. The simulated primary and export production
in the 2090s decreased globally by 6 and 13%, respectively, whereas
in the HNLC regions, they increased by 11 and 6%, respectively.
Roughly half of the elevated production could be attributed to the
intensified iron supply. The projected ocean circulation and mixing changes
are consistent with recent observations of responses to the warming climate
and with other Coupled Model Intercomparison Project model projections. We
conclude that future ocean circulation has the potential to increase iron supply to
HNLC waters and will potentially buffer future reductions in ocean
productivity. |
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