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Bacterial salt tolerance is unrelated to soil salinity across an arid agroecosystem salinity gradient

Rousk, Johannes LU ; Elyaabubi, Fathi; Jones, Davey and Godbold, Douglas (2011) In Soil Biology & Biochemistry 43(9). p.1881-1887
Abstract
In arid and semi-arid ecosystems, salinization is a major threat to the productivity of agricultural land. While the influence of other physical and chemical environmental factors on decomposer microorganisms have been intensively studied in soil, the influence of salinity has been less exhaustively assessed. We investigated the influence of soil salinity on soil bacterial communities in soils covering a range of salt levels. We assessed tolerance of the bacterial communities from Libyan agricultural soils forming a salinity gradient to salt (NaCl), by extracting bacterial communities and instantaneously monitoring the concentration–response to added NaCl with the Leucine incorporation technique for bacterial growth. To maximise our... (More)
In arid and semi-arid ecosystems, salinization is a major threat to the productivity of agricultural land. While the influence of other physical and chemical environmental factors on decomposer microorganisms have been intensively studied in soil, the influence of salinity has been less exhaustively assessed. We investigated the influence of soil salinity on soil bacterial communities in soils covering a range of salt levels. We assessed tolerance of the bacterial communities from Libyan agricultural soils forming a salinity gradient to salt (NaCl), by extracting bacterial communities and instantaneously monitoring the concentration–response to added NaCl with the Leucine incorporation technique for bacterial growth. To maximise our ability to detect differences in bacterial salt tolerance between the soils, we also repeated the assessment of bacterial growth tolerance after one month incubation with 1 or 2% added organic matter additions to stimulate microbial growth levels. We could establish clear concentration–response relationships between bacterial growth and soil salinity, demonstrating an accurate assessment of bacterial tolerance. The in situ soil salinity in the studied soils ranged between 0.64 and 2.73 mM Na (electrical conductivities of 0.74–4.12 mS cm−1; cation exchange capacities of 20–37 mmolc kg−1) and the bacterial tolerance indicated by the concentration inhibiting 50% of the bacterial growth (EC50) varied between 30 and 100 mM Na or between electrical conductivities of 3.0 and 10.7 mS cm−1. There was no relationship between in situ soil salinity and the salt tolerance of the soil bacterial communities. Our results suggest that soil salinity was not a decisive factor for bacterial growth, and thus for structuring the decomposer community, in the studied soils. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Soil salinity, Decomposition, Arid soils, Salt, Tolerance, Ecotoxicology, Selective pressure, Leucine incorporation, Bacterial growth, Microbial community composition, Biomass
in
Soil Biology & Biochemistry
volume
43
issue
9
pages
1881 - 1887
publisher
Elsevier
external identifiers
  • wos:000294942300015
  • scopus:80051469687
ISSN
0038-0717
DOI
10.1016/j.soilbio.2011.05.007
project
Carbon drivers and microbial agents of soil respiration
Interaction between fungi and bacteria in soil
Effect of environmental factors on fungal and bacterial growth in soil
Microbial carbon-use efficiency
language
English
LU publication?
yes
id
723c75ea-f6ff-4aaa-840d-c63ca506b161 (old id 2154159)
date added to LUP
2011-09-28 12:29:22
date last changed
2017-09-24 03:26:53
@article{723c75ea-f6ff-4aaa-840d-c63ca506b161,
  abstract     = {In arid and semi-arid ecosystems, salinization is a major threat to the productivity of agricultural land. While the influence of other physical and chemical environmental factors on decomposer microorganisms have been intensively studied in soil, the influence of salinity has been less exhaustively assessed. We investigated the influence of soil salinity on soil bacterial communities in soils covering a range of salt levels. We assessed tolerance of the bacterial communities from Libyan agricultural soils forming a salinity gradient to salt (NaCl), by extracting bacterial communities and instantaneously monitoring the concentration–response to added NaCl with the Leucine incorporation technique for bacterial growth. To maximise our ability to detect differences in bacterial salt tolerance between the soils, we also repeated the assessment of bacterial growth tolerance after one month incubation with 1 or 2% added organic matter additions to stimulate microbial growth levels. We could establish clear concentration–response relationships between bacterial growth and soil salinity, demonstrating an accurate assessment of bacterial tolerance. The in situ soil salinity in the studied soils ranged between 0.64 and 2.73 mM Na (electrical conductivities of 0.74–4.12 mS cm−1; cation exchange capacities of 20–37 mmolc kg−1) and the bacterial tolerance indicated by the concentration inhibiting 50% of the bacterial growth (EC50) varied between 30 and 100 mM Na or between electrical conductivities of 3.0 and 10.7 mS cm−1. There was no relationship between in situ soil salinity and the salt tolerance of the soil bacterial communities. Our results suggest that soil salinity was not a decisive factor for bacterial growth, and thus for structuring the decomposer community, in the studied soils.},
  author       = {Rousk, Johannes and Elyaabubi, Fathi and Jones, Davey and Godbold, Douglas},
  issn         = {0038-0717},
  keyword      = {Soil salinity,Decomposition,Arid soils,Salt,Tolerance,Ecotoxicology,Selective pressure,Leucine incorporation,Bacterial growth,Microbial community composition,Biomass},
  language     = {eng},
  number       = {9},
  pages        = {1881--1887},
  publisher    = {Elsevier},
  series       = {Soil Biology & Biochemistry},
  title        = {Bacterial salt tolerance is unrelated to soil salinity across an arid agroecosystem salinity gradient},
  url          = {http://dx.doi.org/10.1016/j.soilbio.2011.05.007},
  volume       = {43},
  year         = {2011},
}