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Experimental drought alters rates of soil respiration and methanogenesis but not carbon exchange in soil of a temperate fen

Title data

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. Vol. 40 (2008) Issue 7 . - pp. 1781-1791.
ISSN 0038-0717
DOI: https://doi.org/10.1016/j.soilbio.2008.03.019

Abstract in another language

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.

Further data

Item Type: Article in a journal
Refereed: Yes
Additional notes: BAYCEER63326
Institutions of the University: Faculties > Faculty of Biology, Chemistry and Earth Sciences > Department of Earth Sciences > Chair Hydrology
Research Institutions > Research Centres > Bayreuth Center of Ecology and Environmental Research- BayCEER
Research Institutions > Research Units > Limnological Research Station
Faculties
Faculties > Faculty of Biology, Chemistry and Earth Sciences
Faculties > Faculty of Biology, Chemistry and Earth Sciences > Department of Earth Sciences
Research Institutions
Research Institutions > Research Centres
Research Institutions > Research Units
Result of work at the UBT: Yes
DDC Subjects: 500 Science
Date Deposited: 15 May 2015 14:47
Last Modified: 27 Apr 2016 09:11
URI: https://eref.uni-bayreuth.de/id/eprint/13739