Carbon dioxide production from peatland soil profiles: The influence of temperature, oxic/anoxic conditions and substrate
The authors incubated intact peat cores from depth intervals of 5--15, 15--25, 25--35, and 35--45 cm from ombrotrophic bog, poor fen, and beaver pond margin sections of a cool-temperate peatland. CO{sub 2} production was measured over 12-day incubation periods at 4 and 14 C and under oxic and anoxic conditions. Rates ranged from 0.06 to 0.66 mg CO{sub 2} g{sup {minus}1} dry peat d{sup {minus}1} under oxic conditions and from 0.002 to 0.098 mg CO{sub 2} g{sup {minus}1} d{sup {minus}1} under anoxic conditions, and rates generally decreased with depth in the profiles. When expressed on a volumetric basis, production rates ranged from 0.3 to 23.4 g CO{sub 2} m{sup {minus}3} d{sup {minus}1}, and there was much less variation in CO{sub 2} production rates within profiles because the bulk density of peat increased with depth. The Q{sub 10} quotient, between 4 and 14 C, ranged from 1.0 to 7.7, depending on sample and incubation conditions, with an average of 2.0 for oxic and 2.7 for anoxic conditions. Oxic:anoxic ratios averaged 7:1, 16:1, and 12:1 for the bog, poor fen, and beaver pond margin samples, respectively. Degree of decomposition (von Post index) was the substrate property most strongly correlated with CO{sub 2} production. Based on temperature and incubation data for the peat profiles to a depth of 45 cm, annual decomposition values (k) ranged from 0.016 to 0.060 yr{sup {minus}1} under oxic conditions and from 0.001 to 0.007 yr{sup {minus}1} under anoxic conditions. A model of CO{sub 2} emission from the three sites, based on the incubation data and thermal and water table regime, gave good agreement with measured in situ CO{sub 2} emission rates, although summer emission rates were underpredicted, possibly because of the absence of a root production component in the incubations or because of underestimation of CO{sub 2} production rates in field conditions above the water table.
- Research Organization:
- McGill Univ., Montreal, Quebec (CA)
- OSTI ID:
- 20062528
- Journal Information:
- Soil Science, Vol. 165, Issue 2; Other Information: PBD: Feb 2000; ISSN 0038-075X
- Country of Publication:
- United States
- Language:
- English
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