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| Titel |
Subsurface pH and carbonate saturation state of aragonite on the Chinese side of the North Yellow Sea: seasonal variations and controls |
| VerfasserIn |
W.-D. Zhai, N. Zheng, C. Huo, Y. Xu, H.-D. Zhao, Y.-W. Li, K.-P. Zang, J.-Y. Wang, X.-M. Xu |
| 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. 4 ; Nr. 11, no. 4 (2014-02-26), S.1103-1123 |
| Datensatznummer |
250117245
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| Publikation (Nr.) |
 copernicus.org/bg-11-1103-2014.pdf |
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| Zusammenfassung |
| Based upon eight field surveys conducted between May 2011 and May 2012, we
investigated seasonal variations in pH, carbonate saturation state of
aragonite (Ωarag), and ancillary data on the Chinese side of
the North Yellow Sea, a western North Pacific continental margin of major
economic importance. Subsurface waters were CO2-undersaturated in May
and nearly in equilibrium with atmospheric CO2 in June. From July to
October, the fugacity of CO2 (fCO2) of bottom water gradually
increased from 438 ± 44 μatm to 630 ± 84 μatm, and
pHT decreased from 8.02 ± 0.04 to 7.88 ± 0.06 due to local
aerobic remineralization of primary-production-induced biogenic particles.
The subsurface community respiration rates in summer and autumn were
estimated to be from 0.80 to 1.08 μmol-O2 kg−1 d−1 within a
relatively high salinity range of 31.63 to 32.25. From November to May in
the next year, however, subsurface fCO2 gradually decreased and pH
increased due to cooling and water column ventilation. The corresponding
bottom water Ωarag was 1.85 ± 0.21 (May), 1.79 ± 0.24 (June),
1.75 ± 0.27 (July), 1.76 ± 0.29 (August), 1.45 ± 0.31 (October), 1.52 ± 0.25 (November), and 1.41 ± 0.12
(January). Extremely low Ωarag values (from 1.13 to 1.40) were
observed mainly in subsurface waters within the high salinity range of 31.63
to 32.25, which covered a major fraction of the study area in October and
November. Of the China seas, the North Yellow Sea represents one of the systems
most vulnerable to the potential negative effects of ocean acidification. |
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