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Knorr, Klaus-Holger ; Oosterwoud, Marieke R. ; Blodau, Christian:
Experimental drought alters rates of soil respiration and methanogenesis but not carbon exchange in soil of a temperate fen.
In: Soil Biology & Biochemistry.
Bd. 40
(2008)
Heft 7
.
- S. 1781-1791.
ISSN 0038-0717
DOI: https://doi.org/10.1016/j.soilbio.2008.03.019
Abstract
The impact of intensified drought and rewetting on C cycling in peatlands is debated. We conducteddrying/rewetting (DW) experiments with intact monoliths of a temperate fen over a period of 10 months.One treatment with original vegetation (DW-V) and one defoliated treatment (DW-D) were rewettedafter an experimental drought of 50 days; another treatment was kept permanently wet (W-V). Soilwater content was determined by the TDR technique, C fluxes from chamber measurements and gasprofiles in the soils, and respiration from mass balancing CO2 and CH4 fluxes in the peat using hourly toweekly data. Zones of high root associated respiration were determined from a 13C labeling experiment.Autotrophic respiration contributed from 55 to 65% to an average ecosystem respiration (ER) of 92 (DWD),211 (DW-V), and 267 mmolm2 d1 (W-V). Photosynthesis ranged from 0 (DW-D) to 450 mmolm2d1 (W-V), and strongly declined for about 30 days after rewetting (DW-V), while ER remained constantduring the drying and rewetting event. Drying raised air-filled porosity in the soil to 2–13%, temporarilyincreased respiration to estimated anaerobic and aerobic rates of up to 550 and 1000 nmol cm3 d1, anddelayed methane production and emission by weeks to months. Root associated respiration wasconcentrated in the uppermost peat layer. In spite of clear relative changes in respiration during and afterdrought, the impact on carbon exchange with the atmosphere was small. We attribute this finding to theimportance of respiration in the uppermost and soil layer, which remained moist and aerated, and theinsensitivity of autotrophic respiration to drought. We expect a similar dynamics to occur in othertemperate wetland soils in which soil respiration is concentrated near the peatland surface, such as richminerotrophic fens.
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| Publikationsform: | Artikel in einer Zeitschrift |
|---|---|
| Begutachteter Beitrag: | Ja |
| Zusätzliche Informationen: | BAYCEER63326 |
| Institutionen der Universität: | Fakultäten > Fakultät für Biologie, Chemie und Geowissenschaften > Fachgruppe Geowissenschaften > Lehrstuhl Hydrologie Forschungseinrichtungen > Forschungszentren > Bayreuther Zentrum für Ökologie und Umweltforschung - BayCEER Forschungseinrichtungen > Forschungsstellen > Limnologische Forschungsstation Fakultäten Fakultäten > Fakultät für Biologie, Chemie und Geowissenschaften Fakultäten > Fakultät für Biologie, Chemie und Geowissenschaften > Fachgruppe Geowissenschaften Forschungseinrichtungen Forschungseinrichtungen > Forschungszentren Forschungseinrichtungen > Forschungsstellen |
| Titel an der UBT entstanden: | Ja |
| Themengebiete aus DDC: | 500 Naturwissenschaften und Mathematik |
| Eingestellt am: | 15 Mai 2015 14:47 |
| Letzte Änderung: | 27 Apr 2016 09:11 |
| URI: | https://eref.uni-bayreuth.de/id/eprint/13739 |