 |
| Titel |
Insights into mechanisms governing forest carbon response to nitrogen deposition: a model-data comparison using observed responses to nitrogen addition |
| VerfasserIn |
R. Q. Thomas, G. B. Bonan, C. L. Goodale |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1726-4170
|
| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 10, no. 6 ; Nr. 10, no. 6 (2013-06-17), S.3869-3887 |
| Datensatznummer |
250018289
|
| Publikation (Nr.) |
 copernicus.org/bg-10-3869-2013.pdf |
|
|
|
|
|
| Zusammenfassung |
| In many forest ecosystems, nitrogen (N) deposition enhances plant uptake of
carbon dioxide, thus reducing climate warming from fossil fuel emissions.
Therefore, accurately modeling how forest carbon (C) sequestration responds
to N deposition is critical for understanding how future changes in N
availability will influence climate. Here, we use observations of forest C
response to N inputs along N deposition gradients and at five temperate
forest sites with fertilization experiments to test and improve a global
biogeochemical model (CLM-CN 4.0). We show that the CLM-CN plant C growth
response to N deposition was smaller than observed and the modeled response
to N fertilization was larger than observed. A set of modifications to the
CLM-CN improved the correspondence between model predictions and
observational data (1) by increasing the aboveground C storage in response
to historical N deposition (1850–2004) from 14 to 34 kg C per additional kg N added through deposition and (2) by decreasing the aboveground net primary
productivity response to N fertilization experiments from 91 to 57 g C m−2 yr−1. Modeled growth response to N deposition was most
sensitive to altering the processes that control plant N uptake and the
pathways of N loss. The response to N deposition also increased with a more
closed N cycle (reduced N fixation and N gas loss) and decreased when
prioritizing microbial over plant uptake of soil inorganic N. The net effect
of all the modifications to the CLM-CN resulted in greater retention of N
deposition and a greater role of synergy between N deposition and rising
atmospheric CO2 as a mechanism governing increases in temperate forest
primary production over the 20th century. Overall, testing models with both
the response to gradual increases in N inputs over decades (N deposition)
and N pulse additions of N over multiple years (N fertilization) allows for
greater understanding of the mechanisms governing C–N coupling. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|