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| Titel |
The stoichiometry of inorganic carbon and nutrient removal in the Mississippi River plume and adjacent continental shelf |
| VerfasserIn |
W.-J. Huang, W.-J. Cai, R. T. Powell, S. E. Lohrenz, Y. Wang, L.-Q. Jiang, C. S. Hopkinson |
| 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 ; 9, no. 7 ; Nr. 9, no. 7 (2012-07-30), S.2781-2792 |
| Datensatznummer |
250007200
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| Publikation (Nr.) |
 copernicus.org/bg-9-2781-2012.pdf |
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| Zusammenfassung |
| The stoichiometry of dissolved inorganic carbon (DIC) and nutrients during
biological uptake is widely assumed to follow the Redfield ratios
(especially the C / N ratio) in large river plume ecosystems. However, this
assumption has not been systematically examined and documented, because DIC
and nutrients are rarely studied simultaneously in river plume areas and
interpretation of ratios can be confounded by strong river–ocean mixing as
well as intense biological activity. We examined stoichiometric ratios of
DIC and nutrients (NO3-, PO43- and Si[OH]4) in the
Mississippi River plume and adjacent continental shelf in June 2003 and
August 2004 and calculated biological removal as the difference between
observed concentrations and those predicted from conservative mixing, as
determined from a multi-end-member mixing model and observed salinity and
total alkalinity. Despite complex physical and biogeochemical influences,
relationships between DIC and nutrients were strongly dependent on salinity
range and geographic location, and influenced by biological removal. Lower
C / Si and N / Si ratios in one nearshore area were likely due to localized
input of high Si and low NO3- water from adjacent wetlands or
preferential removal of nitrogen in the area. When net biological uptake was
separated from river–ocean mixing and corrected for preferential N removal,
the stoichiometric ratio of C / N / Si was similar to the Redfield ratio, thus
supporting the applicability of the Redfield-type C / N / Si ratios in
river-plume biogeochemical models. |
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