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| Titel |
Modelling the ecosystem effects of nitrogen deposition: Model of Ecosystem Retention and Loss of Inorganic Nitrogen (MERLIN |
| VerfasserIn |
B. J. Cosby, R. C. Ferrier, A. Jenkins, B. A. Emmett, R. F. Wright, A. Tietema |
| 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 ; 1, no. 1 ; Nr. 1, no. 1, S.137-158 |
| Datensatznummer |
250000089
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| Publikation (Nr.) |
 copernicus.org/hess-1-137-1997.pdf |
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| Zusammenfassung |
| A catchment-scale mass-balance model of linked carbon
and nitrogen cycling in ecosystems has been developed for simulating leaching
losses of inorganic nitrogen. The model (MERLIN) considers linked biotic
and abiotic processes affecting the cycling and storage of nitrogen. The
model is aggregated in space and time and contains compartments intended
to be observable and/or interpretable at the plot or catchment scale. The
structure of the model includes the inorganic soil, a plant compartment
and two soil organic compartments. Fluxes in and out of the ecosystem and
between compartments are regulated by atmospheric deposition, hydrological
discharge, plant uptake, litter production, wood production, microbial
immobilization, mineralization, nitrification, and denitrification. Nitrogen
fluxes are controlled by carbon productivity, the C:N ratios of organic
compartments and inorganic nitrogen in soil solution. Inputs required are:
1) temporal sequences of carbon fluxes and pools- 2) time series of hydrological
discharge through the soils, 3) historical and current external sources
of inorganic nitrogen; 4) current amounts of nitrogen in the plant and
soil organic compartments; 5) constants specifying the nitrogen uptake
and immobilization characteristics of the plant and soil organic compartments;
and 6) soil characteristics such as depth, porosity, bulk density, and
anion/cation exchange constants. Outputs include: 1) concentrations and
fluxes of NO3 and NH4 in soil solution and runoff;
2) total nitrogen contents
of the organic and inorganic compartments; 3) C:N ratios of the aggregated
plant and soil organic compartments; and 4) rates of nitrogen uptake and
immobilization and nitrogen mineralization. The behaviour of the model
is assessed for a combination of land-use change and nitrogen deposition
scenarios in a series of speculative simulations. The results of the simulations
are in broad agreement with observed and hypothesized behaviour of nitrogen
dynamics in growing forests receiving nitrogen deposition. |
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