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Development of metal tolerance in soil bacterial communities exposed to experimentally increased metal levels

Diaz-Ravina, M and Bååth, Erland LU (1996) In Applied and Environmental Microbiology 62(8). p.2970-2977
Abstract
The development of metal tolerance in soil bacterial communities exposed to different heavy metals was examined under laboratory conditions. An agricultural soil amended with different Zn concentrations was studied most intensively, and measurements were made over a 28-month incubation period by means of the thymidine incorporation technique. Tolerance levels were not affected by metal concentrations lower than 2 mmol of Zn kg (dry weight) of soil(sup-1), but above this value, the level of Zn tolerance increased exponentially with the logarithm of the soil Zn concentration. An increased metal tolerance was detected after only 2 days of Zn exposure. Thereafter, stable tolerance values were observed at different sampling times for bacterial... (More)
The development of metal tolerance in soil bacterial communities exposed to different heavy metals was examined under laboratory conditions. An agricultural soil amended with different Zn concentrations was studied most intensively, and measurements were made over a 28-month incubation period by means of the thymidine incorporation technique. Tolerance levels were not affected by metal concentrations lower than 2 mmol of Zn kg (dry weight) of soil(sup-1), but above this value, the level of Zn tolerance increased exponentially with the logarithm of the soil Zn concentration. An increased metal tolerance was detected after only 2 days of Zn exposure. Thereafter, stable tolerance values were observed at different sampling times for bacterial communities exposed to up to 8 mmol of Zn kg (dry weight)(sup-1), indicating no changes in tolerance with time. The tolerance of bacterial communities exposed to 32 mmol of Zn kg (dry weight)(sup-1) increased rapidly within the second week of incubation, but then the values remained unchanged until the end of the experiment. Bacterial communities from soil contaminated with 16 mmol of Zn kg (dry weight)(sup-1) showed an increase of the same magnitude, but the increase started later, after 4 months of incubation, and took place for a much longer period (more than 1 year). Cd, Cu, and Ni addition also resulted in metal-tolerant communities, and the level of tolerance increased with prolonged incubations of the soils. The bacterial community at the end of the incubation period also exhibited a lower pH optimum and an increased tolerance to low osmotic potential. The results suggest that the increase in metal tolerance of the community after adding metals can be attributed to an immediate effect due to the death of sensitive species and a later effect due to different competitive abilities and adaptation of surviving bacteria. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Applied and Environmental Microbiology
volume
62
issue
8
pages
2970 - 2977
publisher
American Society for Microbiology
external identifiers
  • wos:A1996UZ99600046
  • scopus:0029659521
ISSN
0099-2240
language
English
LU publication?
yes
id
ed2a7a4d-3172-460d-9a60-df7ef909b732 (old id 132935)
alternative location
http://aem.asm.org/cgi/content/abstract/62/8/2970
date added to LUP
2007-06-29 09:26:54
date last changed
2017-07-30 03:48:12
@article{ed2a7a4d-3172-460d-9a60-df7ef909b732,
  abstract     = {The development of metal tolerance in soil bacterial communities exposed to different heavy metals was examined under laboratory conditions. An agricultural soil amended with different Zn concentrations was studied most intensively, and measurements were made over a 28-month incubation period by means of the thymidine incorporation technique. Tolerance levels were not affected by metal concentrations lower than 2 mmol of Zn kg (dry weight) of soil(sup-1), but above this value, the level of Zn tolerance increased exponentially with the logarithm of the soil Zn concentration. An increased metal tolerance was detected after only 2 days of Zn exposure. Thereafter, stable tolerance values were observed at different sampling times for bacterial communities exposed to up to 8 mmol of Zn kg (dry weight)(sup-1), indicating no changes in tolerance with time. The tolerance of bacterial communities exposed to 32 mmol of Zn kg (dry weight)(sup-1) increased rapidly within the second week of incubation, but then the values remained unchanged until the end of the experiment. Bacterial communities from soil contaminated with 16 mmol of Zn kg (dry weight)(sup-1) showed an increase of the same magnitude, but the increase started later, after 4 months of incubation, and took place for a much longer period (more than 1 year). Cd, Cu, and Ni addition also resulted in metal-tolerant communities, and the level of tolerance increased with prolonged incubations of the soils. The bacterial community at the end of the incubation period also exhibited a lower pH optimum and an increased tolerance to low osmotic potential. The results suggest that the increase in metal tolerance of the community after adding metals can be attributed to an immediate effect due to the death of sensitive species and a later effect due to different competitive abilities and adaptation of surviving bacteria.},
  author       = {Diaz-Ravina, M and Bååth, Erland},
  issn         = {0099-2240},
  language     = {eng},
  number       = {8},
  pages        = {2970--2977},
  publisher    = {American Society for Microbiology},
  series       = {Applied and Environmental Microbiology},
  title        = {Development of metal tolerance in soil bacterial communities exposed to experimentally increased metal levels},
  volume       = {62},
  year         = {1996},
}