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Titel |
N/P ratio of nutrient uptake in the Baltic Sea |
VerfasserIn |
Z. Wan, L. Jonasson, H. Bi |
Medientyp |
Artikel
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Sprache |
Englisch
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ISSN |
1812-0784
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Digitales Dokument |
URL |
Erschienen |
In: Ocean Science ; 7, no. 5 ; Nr. 7, no. 5 (2011-10-31), S.693-704 |
Datensatznummer |
250004808
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Publikation (Nr.) |
copernicus.org/os-7-693-2011.pdf |
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Zusammenfassung |
The N/P ratio of nutrient uptake, the change of dissolved inorganic nitrogen
(DIN) relative to the change of dissolved inorganic phosphorus (DIP), is a
key parameter for many ecological models. In the Baltic Sea ecosystem, the
N/P ratio of nutrient uptake varies among different basins and different
seasons. The N/P ratio of nutrient alteration, i.e., the ratio of DIN to DIP
altered before and after spring blooms, is not the same as the N/P ratio of
nutrient uptake, but the former can be regarded as an indicator of the
latter in the Baltic Sea. Based on the observed N/P ratio of nutrient
alteration, we hypothesize a non-Redfield N/P ratio of nutrient uptake. The
3-D-ecosystem model ERGOM coupled with the circulation model DMI-BSHcmod was
used to test this hypothesis. When the Redfield ratio was used in the model,
the DIP surplus after spring blooms was too high and resulted in excessive
growth of cyanobacteria and too much nitrogen fixation. When the
non-Redfield ratio was used in the model, these problems tended to
disappear. In summary, we show that: (1) the Redfield N/P ratio of nutrient
uptake in the Baltic Sea tends to be too high; (2) a N/P ratio of 10:1
appears to work better than the Redfield value; and (3) the N/P ratio of
nutrient uptake in the Baltic Proper during spring blooms is around 6:1. As
the model limitation using one identical value for two N/P ratios for
nutrient uptake and remineralization, the quantitative conclusions are only
convincing as a model parameter even though it obviously improves model
predictions. Whether this model parameter is consistent with the biological
nutrient uptake is worth being further verified with some laboratory
investigations or simulations using a more sophisticated model with
independent N/P ratios for nutrient uptake and remineralization. |
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