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| Titel |
Organic nutrients and excess nitrogen in the North Atlantic subtropical gyre |
| VerfasserIn |
A. Landolfi, A. Oschlies, R. Sanders |
| 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 ; 5, no. 5 ; Nr. 5, no. 5 (2008-09-01), S.1199-1213 |
| Datensatznummer |
250002820
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| Publikation (Nr.) |
 copernicus.org/bg-5-1199-2008.pdf |
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| Zusammenfassung |
| To enable an accurate estimate of total excess nitrogen (N) in the North
Atlantic, a new tracer TNxs is defined, which includes the contribution of
organic nutrients to the assessment of N:P stoichiometric anomalies. We
measured the spatial distribution of TNxs within the subtropical North Atlantic using
data from a trans-Atlantic section across 24.5° N occupied in 2004. We
then employ three different approaches to infer rates of total excess
nitrogen accumulation using pCFC-12 derived ventilation ages (a TNxs
vertical integration, a one end-member and a two-end member mixing model).
Despite some variability among the different methods the dissolved organic
nutrient fraction always contributes to about half of the TNxs accumulation,
which is in the order of 9.38±4.18×1011 mol N y−1.
We suggest that neglecting organic nutrients in stoichiometric
balances of the marine N and P inventories can lead to systematic errors
when estimating deviations of nitrogen excess or deficit relative to the Redfield ratio
in the oceans. For the North Atlantic the inclusion of the organic fraction to the excess nitrogen pool
leads to an upward revision of the N supply by N2 fixation to
10.2±6.9×1011 mol N y−1. |
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