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| Titel |
Winter-to-summer evolution of pCO2 in surface water and air–sea CO2 flux in the seasonal ice zone of the Southern Ocean |
| VerfasserIn |
D. Nomura, H. Yoshikawa-Inoue, S. Kobayashi, S. Nakaoka, K. Nakata, G. Hashida |
| 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. 20 ; Nr. 11, no. 20 (2014-10-16), S.5749-5761 |
| Datensatznummer |
250117646
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| Publikation (Nr.) |
 copernicus.org/bg-11-5749-2014.pdf |
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| Zusammenfassung |
| Partial pressure of CO2 (pCO2) in surface water
and vertical profiles of the carbonate system parameters were measured
during austral summer in the Indian sector of the Southern Ocean
(64–67° S, 32–58° E) in January 2006 to understand the
CO2 dynamics of seawater in the seasonal ice zone. Surface-water
pCO2 ranged from 275 to 400 μatm, and longitudinal variations
reflected the dominant influence of water temperature and dilution by
sea ice meltwater between 32 and 40° E and biological
productivity between 40 and 58° E. Using carbonate
system data from the temperature minimum layer
(−1.9 °C < T < −1.5 °C, 34.2 < S < 34.5), we examined
the winter-to-summer evolution of surface-water pCO2 and the factors
affecting it. Our results indicate that pCO2 increased by as much as 32 μatm,
resulting mainly from the increase in water temperature. At the same time as changes in sea ice concentration and surface-water pCO2,
the air–sea CO2 flux, which consists of the exchange of CO2 between sea ice
and atmosphere, changed from −1.1 to +0.9 mmol C m−2 day−1
between winter and summer. These results suggest that, for the atmosphere,
the seasonal ice zone acts as a CO2 sink in winter and a temporary
CO2 source in summer immediately after the retreat of sea ice.
Subsequent biological productivity likely decreases surface-water pCO2
and the air–sea CO2 flux becomes negative, such that in summer the study
area is again a CO2 sink with respect to the atmosphere. |
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