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Long-term ozone effects on vegetation, microbial community and methane dynamics of boreal peatland microcosms in open-field conditions

Morsky, Sami K.; Haapala, Jaana K.; Rinnan, Riikka LU ; Tiiva, Paivi; Saarnio, Sanna; Silvola, Jouko; Holopainen, Toini and Martikainen, Pertti J. (2008) In Global Change Biology 14(8). p.1891-1903
Abstract
To study the effects of elevated ozone concentration on methane dynamics and a sedge species, Eriophorum vaginatum, we exposed peatland microcosms, isolated by coring from an oligotrophic pine fen, to double ambient ozone concentration in an open-air ozone exposure field for four growing seasons. The field consists of eight circular plots of which four were fumigated with elevated ozone concentration and four were ambient controls. At the latter part of the first growing season (week 33, 2003), the methane emission was 159 +/- 14 mg CH4 m(-2) day(-1) (mean +/- SE) in the ozone treatment and 214 +/- 8 mg CH4 m(-2) day(-1) under the ambient control. However, towards the end of the experiment the ozone treatment slightly, but consistently,... (More)
To study the effects of elevated ozone concentration on methane dynamics and a sedge species, Eriophorum vaginatum, we exposed peatland microcosms, isolated by coring from an oligotrophic pine fen, to double ambient ozone concentration in an open-air ozone exposure field for four growing seasons. The field consists of eight circular plots of which four were fumigated with elevated ozone concentration and four were ambient controls. At the latter part of the first growing season (week 33, 2003), the methane emission was 159 +/- 14 mg CH4 m(-2) day(-1) (mean +/- SE) in the ozone treatment and 214 +/- 8 mg CH4 m(-2) day(-1) under the ambient control. However, towards the end of the experiment the ozone treatment slightly, but consistently, enhanced the methane emission. At the end of the third growing season (2005), microbial biomass (estimated by phospholipid fatty acid biomarkers) was higher in peat exposed to ozone (1975 +/- 108 nmol g(-1) dw) than in peat of the control microcosms (1589 +/- 115 nmol g(-1) dw). The concentrations of organic acids in peat pore water showed a similar trend. Elevated ozone did not affect the shoot length or the structure of the sedge E. vaginatum leaves but it slightly increased the total number of sedge leaves towards the end of the experiment. Our results indicate that elevated ozone concentration enhances the general growth conditions of microbes in peat by increasing their substrate availability. However, the methane production did not reflect the increase in the concentration of organic acids, probably because hydrogenotrophic methane production dominated in the peat studied. Although, we used isolated peatland microcosms with limited size as study material, we did not find experimental factors that could have hampered the basic conclusions on the effects of ozone. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
sedge, PLFA, peatland, organic acid, microcosm, Eriophorum vaginatum, methane, wetland, tropospheric ozone
in
Global Change Biology
volume
14
issue
8
pages
1891 - 1903
publisher
Wiley-Blackwell
external identifiers
  • wos:000257712400013
  • scopus:48949120697
ISSN
1354-1013
DOI
10.1111/j.1365-2486.2008.01615.x
language
English
LU publication?
yes
id
e51c6132-085f-4154-8e78-a9cb7d5eda32 (old id 1254982)
date added to LUP
2008-10-17 14:43:43
date last changed
2017-09-03 03:40:56
@article{e51c6132-085f-4154-8e78-a9cb7d5eda32,
  abstract     = {To study the effects of elevated ozone concentration on methane dynamics and a sedge species, Eriophorum vaginatum, we exposed peatland microcosms, isolated by coring from an oligotrophic pine fen, to double ambient ozone concentration in an open-air ozone exposure field for four growing seasons. The field consists of eight circular plots of which four were fumigated with elevated ozone concentration and four were ambient controls. At the latter part of the first growing season (week 33, 2003), the methane emission was 159 +/- 14 mg CH4 m(-2) day(-1) (mean +/- SE) in the ozone treatment and 214 +/- 8 mg CH4 m(-2) day(-1) under the ambient control. However, towards the end of the experiment the ozone treatment slightly, but consistently, enhanced the methane emission. At the end of the third growing season (2005), microbial biomass (estimated by phospholipid fatty acid biomarkers) was higher in peat exposed to ozone (1975 +/- 108 nmol g(-1) dw) than in peat of the control microcosms (1589 +/- 115 nmol g(-1) dw). The concentrations of organic acids in peat pore water showed a similar trend. Elevated ozone did not affect the shoot length or the structure of the sedge E. vaginatum leaves but it slightly increased the total number of sedge leaves towards the end of the experiment. Our results indicate that elevated ozone concentration enhances the general growth conditions of microbes in peat by increasing their substrate availability. However, the methane production did not reflect the increase in the concentration of organic acids, probably because hydrogenotrophic methane production dominated in the peat studied. Although, we used isolated peatland microcosms with limited size as study material, we did not find experimental factors that could have hampered the basic conclusions on the effects of ozone.},
  author       = {Morsky, Sami K. and Haapala, Jaana K. and Rinnan, Riikka and Tiiva, Paivi and Saarnio, Sanna and Silvola, Jouko and Holopainen, Toini and Martikainen, Pertti J.},
  issn         = {1354-1013},
  keyword      = {sedge,PLFA,peatland,organic acid,microcosm,Eriophorum vaginatum,methane,wetland,tropospheric ozone},
  language     = {eng},
  number       = {8},
  pages        = {1891--1903},
  publisher    = {Wiley-Blackwell},
  series       = {Global Change Biology},
  title        = {Long-term ozone effects on vegetation, microbial community and methane dynamics of boreal peatland microcosms in open-field conditions},
  url          = {http://dx.doi.org/10.1111/j.1365-2486.2008.01615.x},
  volume       = {14},
  year         = {2008},
}