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- Title
Microcosm tests of the effects of temperature and microbial species number on the decomposition of Carex aquatilis and Sphagnum fuscum litter from southern boreal peatlands.
- Authors
Thormann, Markus N.; Bayley, Suzanne E.; Currah, Randolph S.
- Abstract
Increased decomposition rates in boreal peatlands with global warming might increase the release of atmospheric greenhouse gases, thereby producing a positive feedback to global warming. How temperature influences microbial decomposers is unclear. We measured in vitro rates of decomposition of senesced sedge leaves and rhizomes (Carex aquatilis), from a fen, and peat moss (Sphagnum fuscum), from a bog, at 14 and 20 °C by the three most frequently isolated fungi and bacteria from these materials. Decomposition rates of the bog litter decreased (5- to 17-fold) with elevated temperatures, and decomposition of the sedge litters was either enhanced (2- to 30-fold) or remained unaffected by elevated temperatures. The increased temperature regime always favoured fungal over bacterial decomposition rates (2- to 3-fold), Different physiological characteristics of these microbes suggest that fungi using polyphenolic polymers as a carbon source cause greater mass losses of these litters. Litter quality exerted a stronger influence on decomposition at elevated temperatures, as Utter rich in nutrients decomposed more quickly than litter poorer in nutrients at higher temperatures (8.0%-25,7% for the sedge litters vs, 0,2% for the bryophyte litter). We conclude that not all peatlands may provide a positive feedback to global warming. Cautious extrapolation of our data to the ecosystem level suggests that decomposition rates in fens may increase and those in bogs may decrease under a global warming scenario.
- Subjects
CAREX; SPHAGNUM fuscum; MICROCOSM &; macrocosm; PEATLANDS; EFFECT of global warming on plants; GLOBAL warming
- Publication
Canadian Journal of Microbiology, 2004, Vol 50, Issue 10, p793
- ISSN
0008-4166
- Publication type
Article
- DOI
10.1139/W04-064