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Titel |
Nitrogen surface water retention in the Baltic Sea drainage basin |
VerfasserIn |
P. Stålnacke, A. Pengerud, A. Vassiljev, E. Smedberg, C.-M. Mörth, H. E. Hägg, C. Humborg, H. E. Andersen |
Medientyp |
Artikel
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Sprache |
Englisch
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ISSN |
1027-5606
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Digitales Dokument |
URL |
Erschienen |
In: Hydrology and Earth System Sciences ; 19, no. 2 ; Nr. 19, no. 2 (2015-02-23), S.981-996 |
Datensatznummer |
250120634
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Publikation (Nr.) |
copernicus.org/hess-19-981-2015.pdf |
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Zusammenfassung |
In this paper, we estimate the surface water retention of nitrogen (N) in
all the 117 drainage basins to the Baltic Sea with the use of a statistical
model (MESAW) for source apportionment of riverine loads of pollutants. Our
results show that the MESAW model was able to estimate the N load at the
river mouth of 88 Baltic Sea rivers, for which we had observed data, with a
sufficient degree of precision and accuracy. The estimated retention
parameters were also statistically significant. Our results show that around
380 000 t of N are annually retained in surface waters draining to the
Baltic Sea. The total annual riverine load from the 117 basins to the Baltic
Sea was estimated at 570 000 t of N, giving a total surface water N
retention of around 40%. In terms of absolute retention values, three
major river basins account for 50% of the total retention in the 117 basins;
i.e. around 104 000 t of N are retained in Neva, 55 000 t in
Vistula and 32 000 t in Oder. The largest retention was found in river
basins with a high percentage of lakes as indicated by a strong relationship
between N retention (%) and share of lake area in the river drainage
areas. For example in Göta älv, we estimated a total N retention of
72%, whereof 67% of the retention occurred in the lakes of that
drainage area (Lake Vänern primarily). The obtained results will
hopefully enable the Helsinki Commission (HELCOM) to refine the nutrient
load targets in the Baltic Sea Action Plan (BSAP), as well as to better
identify cost-efficient measures to reduce nutrient loadings to the Baltic
Sea. |
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