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Comparison of soil fungal/bacterial ratios in a pH gradient using physiological and PLFA-based techniques

Bååth, Erland LU and Anderson, T H (2003) In Soil Biology & Biochemistry 35(7). p.955-963
Abstract
We have compared the total microbial biomass and the fungal/bacterial ratio estimated using substrate-induced respiration (SIR) in combination with the selective inhibition technique and using the phospholipid fatty acid (PLFA) technique in a pH gradient (3.0-7.2) consisting of 53 mature broad-leaved forest soils. A fungal/bacterial biomass index using the PLFA technique was calculated using the PLFA 18:2w6,9 as an indicator of fungal biomass and the sum of 13 bacterial specific PLFAs as indicator of the bacterial biomass. Good linear correlation (p < 0.001) was found between the total microbial biomass estimated with SIR and total PLFAs (totPLFA), indicating that 1 mg biomass-C was equivalent to 130 nmol totPLFA. Both biomass estimates... (More)
We have compared the total microbial biomass and the fungal/bacterial ratio estimated using substrate-induced respiration (SIR) in combination with the selective inhibition technique and using the phospholipid fatty acid (PLFA) technique in a pH gradient (3.0-7.2) consisting of 53 mature broad-leaved forest soils. A fungal/bacterial biomass index using the PLFA technique was calculated using the PLFA 18:2w6,9 as an indicator of fungal biomass and the sum of 13 bacterial specific PLFAs as indicator of the bacterial biomass. Good linear correlation (p < 0.001) was found between the total microbial biomass estimated with SIR and total PLFAs (totPLFA), indicating that 1 mg biomass-C was equivalent to 130 nmol totPLFA. Both biomass estimates were positively correlated to soil pH. The fungal/bacterial ratio measured using the selective inhibition technique decreased significantly with increasing pH from about 9 at pH 3 to approximately 2 at pH 7, while the fungal/bacterial biomass index using PLFA measurements tended to increase slightly with increasing soil pH. Good correlation between the soil content of ergosterol and of the PLFA 18:2w6,9 indicated that the lack of congruency between the two methods in estimating fungal/bacterial ratios was not due to PLFA 18:2w6,9-related non-fungal structures to any significant degree. Several PLFAs were strongly correlated to soil pH (R-2 values > 0.8); for example the PLFAs 16:1w5 and 16:1w7c increased with increasing soil pH, while i16:0 and cy19:0 decreased. A principal component analysis of the total PLFA pattern gave a first component that was strongly correlated to soil pH (R-2 = 0.85, p < 0.001) indicating that the microbial community composition in these beech/beech-oak forest soils was to a large extent determined by soil pH. (Less)
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author
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organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Soil Biology & Biochemistry
volume
35
issue
7
pages
955 - 963
publisher
Elsevier
external identifiers
  • wos:000184125500009
  • scopus:0037628100
ISSN
0038-0717
DOI
10.1016/S0038-0717(03)00154-8
language
English
LU publication?
yes
id
ecfd798c-fbf3-43e8-99b9-38a52c94916b (old id 135718)
date added to LUP
2016-04-01 16:44:52
date last changed
2024-05-11 06:30:29
@article{ecfd798c-fbf3-43e8-99b9-38a52c94916b,
  abstract     = {{We have compared the total microbial biomass and the fungal/bacterial ratio estimated using substrate-induced respiration (SIR) in combination with the selective inhibition technique and using the phospholipid fatty acid (PLFA) technique in a pH gradient (3.0-7.2) consisting of 53 mature broad-leaved forest soils. A fungal/bacterial biomass index using the PLFA technique was calculated using the PLFA 18:2w6,9 as an indicator of fungal biomass and the sum of 13 bacterial specific PLFAs as indicator of the bacterial biomass. Good linear correlation (p &lt; 0.001) was found between the total microbial biomass estimated with SIR and total PLFAs (totPLFA), indicating that 1 mg biomass-C was equivalent to 130 nmol totPLFA. Both biomass estimates were positively correlated to soil pH. The fungal/bacterial ratio measured using the selective inhibition technique decreased significantly with increasing pH from about 9 at pH 3 to approximately 2 at pH 7, while the fungal/bacterial biomass index using PLFA measurements tended to increase slightly with increasing soil pH. Good correlation between the soil content of ergosterol and of the PLFA 18:2w6,9 indicated that the lack of congruency between the two methods in estimating fungal/bacterial ratios was not due to PLFA 18:2w6,9-related non-fungal structures to any significant degree. Several PLFAs were strongly correlated to soil pH (R-2 values &gt; 0.8); for example the PLFAs 16:1w5 and 16:1w7c increased with increasing soil pH, while i16:0 and cy19:0 decreased. A principal component analysis of the total PLFA pattern gave a first component that was strongly correlated to soil pH (R-2 = 0.85, p &lt; 0.001) indicating that the microbial community composition in these beech/beech-oak forest soils was to a large extent determined by soil pH.}},
  author       = {{Bååth, Erland and Anderson, T H}},
  issn         = {{0038-0717}},
  language     = {{eng}},
  number       = {{7}},
  pages        = {{955--963}},
  publisher    = {{Elsevier}},
  series       = {{Soil Biology & Biochemistry}},
  title        = {{Comparison of soil fungal/bacterial ratios in a pH gradient using physiological and PLFA-based techniques}},
  url          = {{http://dx.doi.org/10.1016/S0038-0717(03)00154-8}},
  doi          = {{10.1016/S0038-0717(03)00154-8}},
  volume       = {{35}},
  year         = {{2003}},
}