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| Titel |
Impact of sea ice on the marine iron cycle and phytoplankton productivity |
| VerfasserIn |
S. Wang, D. Bailey, K. Lindsay, J. K. Moore, M. Holland |
| 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. 17 ; Nr. 11, no. 17 (2014-09-08), S.4713-4731 |
| Datensatznummer |
250117579
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| Publikation (Nr.) |
 copernicus.org/bg-11-4713-2014.pdf |
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| Zusammenfassung |
| Iron is a key nutrient for phytoplankton growth in the surface ocean. At high
latitudes, the iron cycle is closely related to the dynamics of sea ice. In
recent decades, Arctic sea ice cover has been declining rapidly and Antarctic
sea ice has exhibited large regional trends. A significant reduction of sea
ice in both hemispheres is projected in future climate scenarios. In order to
adequately study the effect of sea ice on the polar iron cycle, sea ice
bearing iron was incorporated in the Community Earth System Model (CESM). Sea
ice acts as a reservoir for iron during winter and releases the trace metal
to the surface ocean in spring and summer. Simulated iron concentrations in
sea ice generally agree with observations in regions where iron
concentrations are relatively low. The maximum iron concentrations simulated
in Arctic and Antarctic sea ice are much lower than observed, which is likely
due to underestimation of iron inputs to sea ice or missing mechanisms. The
largest iron source to sea ice is suspended sediments, contributing fluxes of
iron of 2.2 × 108 mol Fe month−1 in the Arctic and
4.1 × 106 mol Fe month−1 in the Southern Ocean during
summer. As a result of the iron flux from ice, iron concentrations increase
significantly in the Arctic. Iron released from melting ice increases
phytoplankton production in spring and summer and shifts phytoplankton
community composition in the Southern Ocean. Results for the period of 1998
to 2007 indicate that a reduction of sea ice in the Southern Ocean will have
a negative influence on phytoplankton production. Iron transport by sea ice
appears to be an important process bringing iron to the central Arctic. The
impact of ice to ocean iron fluxes on marine ecosystems is negligible in the
current Arctic Ocean, as iron is not typically the growth-limiting nutrient.
However, it may become a more important factor in the future, particularly in
the central Arctic, as iron concentrations will decrease with declining sea
ice cover and transport. |
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