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Structure of a microbial community in soil after prolonged addition of low levels of simulated acid rain

Pennanen, Taina; Fritze, Hannu; Vanhala, Pekka; Kiikkilä, Oili; Neuvonen, Seppo and Bååth, Erland LU (1998) In Applied and Environmental Microbiology 64(6). p.2173-2180
Abstract
Humus samples were collected 12 growing seasons after the start of a simulated acid rain experiment situated in the subarctic environment. The acid rain was simulated with H2SO4, a combination of H2SO4 and HNO3, and HNO3 at two levels of moderate acidic loads close to the natural anthropogenic pollution levels of southern Scandinavia. The higher levels of acid applications resulted in acidification, as defined by humus chemistry. The concentrations of base cations decreased, while the concentrations of exchangeable H+, Al, and Fe increased. Humus pH decreased from 3.83 to 3.65. Basal respiration decreased with decreasing humus pH, and total microbial biomass, measured by substrate-induced respiration and total amount of phospholipid fatty... (More)
Humus samples were collected 12 growing seasons after the start of a simulated acid rain experiment situated in the subarctic environment. The acid rain was simulated with H2SO4, a combination of H2SO4 and HNO3, and HNO3 at two levels of moderate acidic loads close to the natural anthropogenic pollution levels of southern Scandinavia. The higher levels of acid applications resulted in acidification, as defined by humus chemistry. The concentrations of base cations decreased, while the concentrations of exchangeable H+, Al, and Fe increased. Humus pH decreased from 3.83 to 3.65. Basal respiration decreased with decreasing humus pH, and total microbial biomass, measured by substrate-induced respiration and total amount of phospholipid fatty acids (PLFA), decreased slightly. An altered PLFA pattern indicated a change in the microbial community structure at the higher levels of acid applications. In general, branched fatty acids, typical of gram-positive bacteria, increased in the acid plots. PLFA analysis performed on the bacterial community growing on agar plates also showed that the relative amount of PLFA specific for gram-positive bacteria increased due to the acidification. The changed bacterial community was adapted to the more acidic environment in the acid-treated plots, even though bacterial growth rates, estimated by thymidine and leucine incorporation, decreased with pH. Fungal activity (measured as acetate incorporation into ergosterol) was not affected. This result indicates that bacteria were more affected than fungi by the acidification. The capacity of the bacterial community to utilize 95 different carbon sources was variable and only showed weak correlations to pH. Differences in the toxicities of H2SO4 and HNO3 for the microbial community were not found. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Applied and Environmental Microbiology
volume
64
issue
6
pages
2173 - 2180
publisher
American Society for Microbiology
external identifiers
  • wos:000073904800028
  • scopus:0031778134
ISSN
0099-2240
language
English
LU publication?
yes
id
992c9f73-0cc2-4fba-b43f-5b60b27eecba (old id 132910)
alternative location
http://aem.asm.org/cgi/content/abstract/64/6/2173
date added to LUP
2007-06-29 14:13:46
date last changed
2017-09-24 03:30:30
@article{992c9f73-0cc2-4fba-b43f-5b60b27eecba,
  abstract     = {Humus samples were collected 12 growing seasons after the start of a simulated acid rain experiment situated in the subarctic environment. The acid rain was simulated with H2SO4, a combination of H2SO4 and HNO3, and HNO3 at two levels of moderate acidic loads close to the natural anthropogenic pollution levels of southern Scandinavia. The higher levels of acid applications resulted in acidification, as defined by humus chemistry. The concentrations of base cations decreased, while the concentrations of exchangeable H+, Al, and Fe increased. Humus pH decreased from 3.83 to 3.65. Basal respiration decreased with decreasing humus pH, and total microbial biomass, measured by substrate-induced respiration and total amount of phospholipid fatty acids (PLFA), decreased slightly. An altered PLFA pattern indicated a change in the microbial community structure at the higher levels of acid applications. In general, branched fatty acids, typical of gram-positive bacteria, increased in the acid plots. PLFA analysis performed on the bacterial community growing on agar plates also showed that the relative amount of PLFA specific for gram-positive bacteria increased due to the acidification. The changed bacterial community was adapted to the more acidic environment in the acid-treated plots, even though bacterial growth rates, estimated by thymidine and leucine incorporation, decreased with pH. Fungal activity (measured as acetate incorporation into ergosterol) was not affected. This result indicates that bacteria were more affected than fungi by the acidification. The capacity of the bacterial community to utilize 95 different carbon sources was variable and only showed weak correlations to pH. Differences in the toxicities of H2SO4 and HNO3 for the microbial community were not found.},
  author       = {Pennanen, Taina and Fritze, Hannu and Vanhala, Pekka and Kiikkilä, Oili and Neuvonen, Seppo and Bååth, Erland},
  issn         = {0099-2240},
  language     = {eng},
  number       = {6},
  pages        = {2173--2180},
  publisher    = {American Society for Microbiology},
  series       = {Applied and Environmental Microbiology},
  title        = {Structure of a microbial community in soil after prolonged addition of low levels of simulated acid rain},
  volume       = {64},
  year         = {1998},
}