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Plant-mediated effects of elevated ultraviolet-B radiation on peat microbial communities of a subarctic mire

  • Riikka Rinnan
  • Anne-Marja Nerg
  • Pauliina Ahtoniemi
  • Hanne Suokanerva
  • Toini Holopainen
  • Esko Kyroe
  • Erland Bååth
Publishing year: 2008
Language: English
Pages: 925-937
Publication/Series: Global Change Biology
Volume: 14
Issue: 4
Document type: Journal article
Publisher: Wiley-Blackwell

Abstract english

Elevated ultraviolet-B (UVB) radiation has been reported to have few effects on plants but to alter the soil microbial community composition. However, the effects on soil microorganisms have to be mediated via plants, because direct radiation effects are only plausible on the uppermost millimeters of soil. Here, we assessed secondary effects of UVB on soil microbes. The responses in the dominant plant Eriophorum russeolum, peat pore water and microbial communities in the peat were recorded at a subarctic mire in the middle of the third growing season under field exposure simulating 20% depletion in the ozone layer. The UVB treatment significantly reduced the sucrose and the total soluble sugar (sucrose+glucose+fructose) concentration of the plant leaves while increasing the sucrose concentration in the belowground storage organ rhizome. The starch concentration of the leaves was also slightly reduced by elevated UVB. In the plant roots, carbohydrate concentrations remained unaffected but the total phenolics concentration increased under elevated UVB. We suggest that the simultaneously observed decrease in bacterial growth rate and the altered bacterial community composition are due to UVB-induced changes in the plant photosynthate allocation and potential changes in root exudation. There were no effects of elevated UVB on microbial biomass, peat pore water or nutrient concentrations in the peat. The observed responses are in line with the previously reported lower ecosystem dark respiration under elevated UVB, and they signify that the changed plant tissue quality and lower bacterial activity are likely to reduce decomposition.


  • Biological Sciences
  • peatland
  • microbial community composition
  • biomass
  • microbial
  • Eriophorum
  • carbohydrates
  • bacterial activity
  • Biolog
  • phenolic compounds
  • PLFA
  • ultraviolet radiation


  • Microbial Ecology
  • ISSN: 1354-1013
Erland Bååth
E-mail: erland [dot] baath [at] biol [dot] lu [dot] se

Professor emeritus


+46 46 222 42 64


Sölvegatan 37, Lund