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| Titel |
Fate of N in a peatland, Whim bog: immobilisation in the vegetation and peat, leakage into pore water and losses as N2O depend on the form of N |
| VerfasserIn |
L. J. Sheppard, I. D. Leith, S. R. Leeson, N. Dijk, C. Field, P. Levy |
| 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 ; 10, no. 1 ; Nr. 10, no. 1 (2013-01-10), S.149-160 |
| Datensatznummer |
250017464
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| Publikation (Nr.) |
 copernicus.org/bg-10-149-2013.pdf |
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| Zusammenfassung |
| Peatlands represent a vast carbon reserve that has accumulated under
conditions of low nitrogen availability. Given the strong coupling between
the carbon and nitrogen cycles, we need to establish the consequences of the
increase in reactive nitrogen deposition for the sustainability of
peatlands, and whether the form in which the nitrogen is deposited makes a
difference. We have addressed these questions using a globally unique field
simulation of reactive N deposition as dry deposited ammonia and wet
deposited reduced N, ammonium and oxidised N, nitrate, added as ammonium
chloride or sodium nitrate, to an ombrotrophic peatland, Whim bog in SE
Scotland. Here we report the fate of 56 kg N ha−1 yr−1 additions
over 10 yr and the consequences. The effects of 10 yr of reactive N
additions depended on the form in which the N was applied. Ammonia-N
deposition caused the keystone Sphagnum species, together with the main shrub
Calluna and the pleurocarpous mosses, to disappear, exposing up to 30% of the
peat surface. This led to a significant increase in soil water nitrate and
nitrous oxide emissions. By contrast wet deposited N, despite significantly
reducing the cover of Sphagnum and Pleurozium moss, did not have a detrimental effect on
Calluna cover nor did it significantly change soil water N concentrations or
nitrous oxide emissions. Importantly 10 yr of wet deposited N did not
bare the peat surface nor significantly disrupt the vegetation enabling the
N to be retained within the carbon rich peatland ecosystems. However, given
the significant role of Sphagnum in maintaining conditions that retard
decomposition, this study suggests that all nitrogen forms will eventually compromise
carbon sequestration by peatlands through loss of some keystone Sphagnum species. |
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