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| Titel |
Patterns of dissolved organic carbon and nitrogen fluxes in deciduous and coniferous forests under historic high nitrogen deposition |
| VerfasserIn |
S. Sleutel, J. Vandenbruwane, A. Schrijver, K. Wuyts, B. Moeskops, K. Verheyen, S. Neve |
| 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 ; 6, no. 12 ; Nr. 6, no. 12 (2009-12-01), S.2743-2758 |
| Datensatznummer |
250004211
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| Publikation (Nr.) |
 copernicus.org/bg-6-2743-2009.pdf |
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| Zusammenfassung |
| Numerous recent studies have indicated that dissolved organic carbon (DOC)
and nitrogen (DON) play an important role in C and N cycling in natural
ecosystems, and have shown that N deposition alters the concentrations and
fluxes of dissolved organic substances and may increase leaching losses from
forests. Our study was set up to accurately quantify concentrations and flux
patterns of DOC, DON and dissolved inorganic nitrogen (DIN) in deciduous and
coniferous forest in Flanders, Belgium, under historical high nitrogen
deposition. We measured DOC, DON and DIN concentrations at two weekly
intervals in a silver birch (SB) stand, a corsican pine (CP) stand and a
pine stand with higher N deposition (CPN), and used the SWAP model
(calibrated with PEST) for generating accurate water and matter fluxes. The
input with precipitation was an important source of DON, but not for DOC.
Release of DOC from the forest floor was minimally affected by forest type,
but higher N deposition (CPN stand) caused an 82% increase of DOC
release from the forest floor. Adsorption to mineral soil material rich in
iron and/or aluminum oxyhydroxides was suggested to be the most important
process removing DOC from the soil solution, responsible for substantial
retention (67–84%) of DOC entering the mineral soil profile with forest
floor leachate. Generally, DON was less reactive (i.e. less removal from the
soil solution) than DOC, resulting in decreasing DOC/DON ratios with soil
depth. We found increased DOC retention in the mineral soil as a result of
higher N deposition (84 kg ha−1 yr−1 additional DOC retention in
CPN compared to CP). Overall DON leaching losses were 2.2, 3.3 and
5.0 kg N yr−1 for SB, CP and CPN, respectively, contributing between 9–28%
to total dissolved N (TDN) leaching. The relative contribution to TDN
leaching from DON loss from SB and CP was mainly determined by (large)
differences in DIN leaching. The large TDN leaching losses are alarming,
especially in the CPN stand that was N saturated. |
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