 |
| Titel |
Modeling carbon dynamics in two adjacent spruce forests with different soil conditions in Russia |
| VerfasserIn |
J. Kurbatova, C. Li, A. Varlagin, X. Xiao, N. Vygodskaya |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1726-4170
|
| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 5, no. 4 ; Nr. 5, no. 4 (2008-07-01), S.969-980 |
| Datensatznummer |
250002672
|
| Publikation (Nr.) |
 copernicus.org/bg-5-969-2008.pdf |
|
|
|
|
|
| Zusammenfassung |
| Net ecosystem carbon exchange (NEE) was measured with eddy covariance method
for two adjacent forests located at the southern boundary of European taiga
in Russia in 1999–2004. The two spruce forests shared similar vegetation
composition but differed in soil conditions. The wet spruce forest (WSF)
possessed a thick peat layer (60 cm) with a high water table seasonally
close to or above the soil surface. The dry spruce forest (DSF) had a
relatively thin organic layer (5 cm) with a deep water table (>60 cm). The
measured multi-year average NEE fluxes (2000 and –1440 kg C ha−1yr−1 for WSF and DSF, respectively) indicated that WSF was a source
while DSF a sink of atmospheric carbon dioxide (CO2) during the
experimental years. A process-based model, Forest-DNDC, was employed in the
study to interpret the observations. The modeled multi-year average NEE
fluxes were 1800 and –2200 kg C ha−1yr−1 for WSF and DSF,
respectively, which were comparable with observations. The modeled data also
showed high soil heterotrophic respiration rates at WSF that suggested that
the water table fluctuation at WSF could have played a key role in
determining the negative carbon balance in the wetland ecosystem. A
sensitivity test was conducted by running Forest-DNDC with varied water
table scenarios for WSF. The results indicated that the NEE fluxes from WSF
were highly sensitive to the water table depth. When the water table was
high, the WSF ecosystem maintained as a sink of atmospheric CO2; while
along with the drop of the water table the length of the flooded period
reduced and more organic matter in the soil profile suffered from rapid
decomposition that gradually converted the ecosystem into a source of
atmospheric CO2. The general effect of water table variation on wetland
carbon balance observed from this modeling study could be applicable for a
wide range of wetland ecosystems that have accumulated soil organic carbon
while face hydrological changes under certain climatic or land-use change
scenarios. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|