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Adaptation of soil microbial growth to temperature : Using a tropical elevation gradient to predict future changes

Nottingham, Andrew T. ; Bååth, Erland LU ; Reischke, Stephanie LU ; Salinas, Norma and Meir, Patrick (2019) In Global Change Biology 25(3). p.827-838
Abstract

Terrestrial biogeochemical feedbacks to the climate are strongly modulated by the temperature response of soil microorganisms. Tropical forests, in particular, exert a major influence on global climate because they are the most productive terrestrial ecosystem. We used an elevation gradient across tropical forest in the Andes (a gradient of 20°C mean annual temperature, MAT), to test whether soil bacterial and fungal community growth responses are adapted to long-term temperature differences. We evaluated the temperature dependency of soil bacterial and fungal growth using the leucine- and acetate-incorporation methods, respectively, and determined indices for the temperature response of growth: Q10 (temperature sensitivity... (More)

Terrestrial biogeochemical feedbacks to the climate are strongly modulated by the temperature response of soil microorganisms. Tropical forests, in particular, exert a major influence on global climate because they are the most productive terrestrial ecosystem. We used an elevation gradient across tropical forest in the Andes (a gradient of 20°C mean annual temperature, MAT), to test whether soil bacterial and fungal community growth responses are adapted to long-term temperature differences. We evaluated the temperature dependency of soil bacterial and fungal growth using the leucine- and acetate-incorporation methods, respectively, and determined indices for the temperature response of growth: Q10 (temperature sensitivity over a given 10oC range) and Tmin(the minimum temperature for growth). For both bacterial and fungal communities, increased MAT (decreased elevation) resulted in increases in Q10and Tmin of growth. Across a MAT range from 6°C to 26°C, the Q10and Tmin varied for bacterial growth (Q10–20 = 2.4 to 3.5; Tmin = −8°C to −1.5°C) and fungal growth (Q10–20 = 2.6 to 3.6; Tmin = −6°C to −1°C). Thus, bacteria and fungi did not differ significantly in their growth temperature responses with changes in MAT. Our findings indicate that across natural temperature gradients, each increase in MAT by 1°C results in increases in Tmin of microbial growth by approximately 0.3°C and Q10–20by 0.05, consistent with long-term temperature adaptation of soil microbial communities. A 2°C warming would increase microbial activity across a MAT gradient of 6°C to 26°C by 28% to 15%, respectively, and temperature adaptation of microbial communities would further increase activity by 1.2% to 0.3%. The impact of warming on microbial activity, and the related impact on soil carbon cycling, is thus greater in regions with lower MAT. These results can be used to predict future changes in the temperature response of microbial activity over different levels of warming and over large temperature ranges, extending to tropical regions.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
bacteria, climate warming, fungi, Q, Ratkowsky equation, soil carbon cycle, tropical forest
in
Global Change Biology
volume
25
issue
3
pages
827 - 838
publisher
Wiley-Blackwell
external identifiers
  • pmid:30372571
  • scopus:85059587397
ISSN
1354-1013
DOI
10.1111/gcb.14502
language
English
LU publication?
yes
id
db410e3e-fae7-474e-b91e-477bbf4e293d
date added to LUP
2019-01-22 08:54:24
date last changed
2020-03-29 07:33:09
@article{db410e3e-fae7-474e-b91e-477bbf4e293d,
  abstract     = {<p>Terrestrial biogeochemical feedbacks to the climate are strongly modulated by the temperature response of soil microorganisms. Tropical forests, in particular, exert a major influence on global climate because they are the most productive terrestrial ecosystem. We used an elevation gradient across tropical forest in the Andes (a gradient of 20°C mean annual temperature, MAT), to test whether soil bacterial and fungal community growth responses are adapted to long-term temperature differences. We evaluated the temperature dependency of soil bacterial and fungal growth using the leucine- and acetate-incorporation methods, respectively, and determined indices for the temperature response of growth: Q<sub>10</sub> (temperature sensitivity over a given 10oC range) and T<sub>min</sub>(the minimum temperature for growth). For both bacterial and fungal communities, increased MAT (decreased elevation) resulted in increases in Q<sub>10</sub>and T<sub>min</sub> of growth. Across a MAT range from 6°C to 26°C, the Q<sub>10</sub>and T<sub>min</sub> varied for bacterial growth (Q<sub>10–20</sub> = 2.4 to 3.5; T<sub>min</sub> = −8°C to −1.5°C) and fungal growth (Q<sub>10–20</sub> = 2.6 to 3.6; T<sub>min</sub> = −6°C to −1°C). Thus, bacteria and fungi did not differ significantly in their growth temperature responses with changes in MAT. Our findings indicate that across natural temperature gradients, each increase in MAT by 1°C results in increases in T<sub>min</sub> of microbial growth by approximately 0.3°C and Q<sub>10–20</sub>by 0.05, consistent with long-term temperature adaptation of soil microbial communities. A 2°C warming would increase microbial activity across a MAT gradient of 6°C to 26°C by 28% to 15%, respectively, and temperature adaptation of microbial communities would further increase activity by 1.2% to 0.3%. The impact of warming on microbial activity, and the related impact on soil carbon cycling, is thus greater in regions with lower MAT. These results can be used to predict future changes in the temperature response of microbial activity over different levels of warming and over large temperature ranges, extending to tropical regions.</p>},
  author       = {Nottingham, Andrew T. and Bååth, Erland and Reischke, Stephanie and Salinas, Norma and Meir, Patrick},
  issn         = {1354-1013},
  language     = {eng},
  number       = {3},
  pages        = {827--838},
  publisher    = {Wiley-Blackwell},
  series       = {Global Change Biology},
  title        = {Adaptation of soil microbial growth to temperature : Using a tropical elevation gradient to predict future changes},
  url          = {http://dx.doi.org/10.1111/gcb.14502},
  doi          = {10.1111/gcb.14502},
  volume       = {25},
  year         = {2019},
}