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| Titel |
Technical Note: Precise quantitative measurements of total dissolved inorganic carbon from small amounts of seawater using a gas chromatographic system |
| VerfasserIn |
T. Hansen, B. Gardeler, B. Matthiessen |
| 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 ; 10, no. 10 ; Nr. 10, no. 10 (2013-10-22), S.6601-6608 |
| Datensatznummer |
250085369
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| Publikation (Nr.) |
 copernicus.org/bg-10-6601-2013.pdf |
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| Zusammenfassung |
| Total dissolved inorganic carbon (CT) is one of the most
frequently measured parameters used to calculate the partial pressure of
carbon dioxide in seawater. Its determination has become increasingly
important because of the rising interest in the biological effects of ocean
acidification. Coulometric and infrared detection methods are currently
favored in order to precisely quantify CT. These methods
however are not sufficiently validated for CT measurements of
biological experiments manipulating seawater carbonate chemistry with an
extended CT measurement range
(~1250–2400 μmol kg–1) compared to natural open ocean
seawater (~1950–2200 μmol kg−1). The requirement of
total sample amounts between 0.1–1 L seawater in the coulometric- and
infrared detection methods potentially exclude their use for experiments
working with much smaller volumes. Additionally, precise CT
analytics become difficult with high amounts of biomass (e.g., phytoplankton
cultures) or even impossible in the presence of planktonic calcifiers without
sample pre-filtration. Filtration however, can alter CT
concentration through gas exchange induced by high pressure. Addressing these
problems, we present precise quantification of CT using a small,
basic and inexpensive gas chromatograph as a CT analyzer. Our
technique is able to provide a repeatability of
±3.1 μmol kg−1, given by the pooled standard deviation
over a CT range typically applied in acidification experiments.
200 μL of sample is required to perform the actual CT
measurement. The total sample amount needed is 12 mL. Moreover, we show that
sample filtration is applicable with only minor alteration of the
CT. The method is simple, reliable and with low cumulative
material costs. Hence, it is potentially attractive for all researchers
experimentally manipulating the seawater carbonate system. |
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