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| Titel |
Impact of enhanced vertical mixing on marine biogeochemistry: lessons for geo-engineering and natural variability |
| VerfasserIn |
S. Dutreuil, L. Bopp, A. Tagliabue |
| 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. 5 ; Nr. 6, no. 5 (2009-05-25), S.901-912 |
| Datensatznummer |
250003751
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| Publikation (Nr.) |
 copernicus.org/bg-6-901-2009.pdf |
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| Zusammenfassung |
| Artificially enhanced vertical mixing has been suggested as a means by which
to fertilize the biological pump with subsurface nutrients and thus increase
the oceanic CO2 sink. We use an ocean general circulation and
biogeochemistry model (OGCBM) to examine the impact of artificially enhanced
vertical mixing on biological productivity and atmospheric CO2, as well
as the climatically significant gases nitrous oxide (N2O) and dimethyl
sulphide (DMS) during simulations between 2000 and 2020. Overall, we find a
large increase in the amount of organic carbon exported from surface waters,
but an overall increase in atmospheric CO2 concentrations by 2020. We
quantified the individual effect of changes in dissolved inorganic carbon
(DIC), alkalinity and biological production on the change in pCO2 at
characteristic sites and found the increased vertical supply of carbon rich
subsurface water to be primarily responsible for the enhanced CO2
outgassing, although increased alkalinity and, to a lesser degree,
biological production can compensate in some regions. While ocean-atmosphere
fluxes of DMS do increase slightly, which might reduce radiative forcing,
the oceanic N2O source also expands. Our study has implications for
understanding how natural variability in vertical mixing in different ocean
regions (such as that observed recently in the Southern Ocean) can impact
the ocean CO2 sink via changes in DIC, alkalinity and carbon export. |
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