Abiotic drivers and their interactive effect on the flux and carbon isotope (¹⁴C and δ¹³C) composition of peat-respired CO

Feedbacks to global warming may cause terrestrial ecosystems to add to anthropogenic CO₂ emissions, thus exacerbating climate change. The contribution that soil respiration makes to these terrestrial emissions, particularly from carbon-rich soils such as peatlands, is of significant importance and i...

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Bibliographic Details
Published in:Soil biology & biochemistry 2011, Vol.43 (12), p.2432-2440
Main Authors: Hardie, S.M.L, Garnett, M.H, Fallick, A.E, Rowland, A.P, Ostle, N.J, Flowers, T.H
Format: Article
Language:English
Subjects:
bogs
carbon
carbon dioxide
emissions
field capacity
global warming
isotopes
peat
soil microorganisms
soil organic matter
soil respiration
soil water
statistical analysis
temperature
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Summary:Feedbacks to global warming may cause terrestrial ecosystems to add to anthropogenic CO₂ emissions, thus exacerbating climate change. The contribution that soil respiration makes to these terrestrial emissions, particularly from carbon-rich soils such as peatlands, is of significant importance and its response to changing climatic conditions is of considerable debate. We collected intact soil cores from an upland blanket bog situated within the northern Pennines, England, UK and investigated the individual and interactive effects of three primary controls on soil organic matter decomposition: (i) temperature (5, 10 and 15 °C); (ii) moisture (50 and 100% field capacity – FC); and (iii) substrate quality, using increasing depth from the surface (0–10, 10–20 and 20–30 cm) as an analogue for increased recalcitrance of soil organic material. Statistical analysis of the results showed that temperature, moisture and substrate quality all significantly affected rates of peat decomposition. Q₁₀ values indicated that the temperature sensitivity of older/more recalcitrant soil organic matter significantly increased (relative to more labile peat) under reduced soil moisture (50% FC) conditions, but not under 100% FC, suggesting that soil microorganisms decomposing the more recalcitrant soil material preferred more aerated conditions. Radiocarbon analyses revealed that soil decomposers were able to respire older, more recalcitrant soil organic matter and that the source of the material (deduced from the δ¹³C analyses) subject to decomposition, changed depending on depth in the peat profile.
ISSN:0038-0717
1879-3428