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| Titel |
Intercomparison of carbonate chemistry measurements on a cruise in northwestern European shelf seas |
| VerfasserIn |
M. Ribas-Ribas, V. M. C. Rérolle, D. C. E. Bakker, V. Kitidis, G. A. Lee, I. Brown, E. P. Achterberg, N. J. Hardman-Mountford, T. Tyrrell |
| 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. 16 ; Nr. 11, no. 16 (2014-08-19), S.4339-4355 |
| Datensatznummer |
250117551
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| Publikation (Nr.) |
 copernicus.org/bg-11-4339-2014.pdf |
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| Zusammenfassung |
| Four carbonate system variables were measured in surface waters during a
cruise aimed at investigating ocean acidification impacts traversing
northwestern European shelf seas in the summer of 2011. High-resolution
surface water data were collected for partial pressure of carbon dioxide
(pCO2; using two independent instruments) and pH using the total pH
scale (pHT), in addition to discrete measurements of total
alkalinity and dissolved inorganic carbon. We thus overdetermined the
carbonate system (four measured variables, two degrees of freedom), which
allowed us to evaluate the level of agreement between the variables on a
cruise whose main aim was not intercomparison, and thus where conditions were
more representative of normal working conditions. Calculations of carbonate
system variables from other measurements generally compared well with direct
observations of the same variables (Pearson's correlation coefficient always
greater than or equal to 0.94; mean residuals were similar to the respective
accuracies of the measurements). We therefore conclude that four of the
independent data sets of carbonate chemistry variables were of high quality.
A diurnal cycle with a maximum amplitude of 41 μatm was observed in
the difference between the pCO2 values obtained by the two independent
analytical pCO2 systems, and this was partly attributed to irregular
seawater flows to the equilibrator and partly to biological activity inside
the seawater supply and one of the equilibrators. We discuss how these issues
can be addressed to improve carbonate chemistry data quality on future
research cruises. |
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