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| Titel |
Coupling of surface pCO2 and dissolved oxygen in the northern South China Sea: impacts of contrasting coastal processes |
| VerfasserIn |
W. D. Zhai, M. Dai, W.-J. Cai |
| 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. 11 ; Nr. 6, no. 11 (2009-11-17), S.2589-2598 |
| Datensatznummer |
250004094
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| Publikation (Nr.) |
 copernicus.org/bg-6-2589-2009.pdf |
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| Zusammenfassung |
| We examined the relationship between CO2 partial pressure (pCO2) and
dissolved oxygen (DO) based on a cruise conducted in July 2004 to the
northern South China Sea (111°–118° E
18°–23° N), spanning from estuarine plume, coastal upwelling
and deep basin areas. Distinct relationships between pCO2 and DO
saturation were identified in different regimes. In coastal upwelling areas
and the Pearl River estuary, biological drawdown of pCO2 and production
of O2 were simultaneously observed. The two properties were coupled with
each other primarily via photosynthesis and respiration. The stoichiometric
relationship of the two properties however, was quite different in these two
environments due to different values of the Revelle factor. In the offshore
areas, apart from the estuary and upwelling, the dynamics of pCO2 and DO
were mainly influenced by air-sea exchange during water mixing. Given the
fact that air-sea re-equilibration of O2 is much faster than that of
CO2, the observed pCO2-DO relationship deviated from that of the
theoretical prediction based on the Redfield relationship in the offshore
areas. Although this study is subject to the limited temporal and spatial
coverage of sampling, we have demonstrated a simple procedure to evaluate the
community metabolic status based on a combination of high-resolution surface
pCO2 and DO measurements, which may have applicability in many coastal
systems with a large gradient of changes in their physical and biogeochemical
conditions. |
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