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| Titel |
Contribution of non-carbonate anions to total alkalinity and overestimation of pCO2 in New England and New Brunswick rivers |
| VerfasserIn |
C. W. Hunt, J. E. Salisbury, D. Vandemark |
| 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 ; 8, no. 10 ; Nr. 8, no. 10 (2011-10-31), S.3069-3076 |
| Datensatznummer |
250006174
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| Publikation (Nr.) |
 copernicus.org/bg-8-3069-2011.pdf |
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| Zusammenfassung |
| Total alkalinity (TAlk) has long been used to evaluate the buffering
capacity of aquatic systems. TAlk has also been used, together with
measurements of either pH or dissolved inorganic carbon (DIC), to indirectly
estimate the partial pressure of carbon dioxide (pCO2) in inland
waters, estuaries, and marine systems. These estimates typically assume that
carbonate and bicarbonate ions comprise nearly all the species contributing
to TAlk; however, other inorganic and organic acids have the potential to
contribute significant non-carbonate alkalinity. To evaluate the potential
for error in using TAlk to estimate pCO2, we measured pH, TAlk, and DIC
in samples of river water. Estimates of pCO2 derived from TAlk and pH
measurements were higher than pCO2 estimates derived from DIC and pH by
13–66%. We infer that this overestimate is due to the presence of
significant non-carbonate alkalinity (NC-Alk). This study also describes the
relative proportions of carbonate- and non-carbonate alkalinity measured in
15 river systems located in northern New England (USA) and New Brunswick
(Canada). NC-Alk represents a significant buffering component in these river
systems (21–∼100% of TAlk), and failure to account for NC-Alk
(which cannot directly contribute to pCO2) leads to the overestimation
of carbon dioxide release to the atmosphere. |
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