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

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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 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.

Detaljer

Författare
  • Andrew T. Nottingham
  • Erland Bååth
  • Stephanie Reischke
  • Norma Salinas
  • Patrick Meir
Enheter & grupper
Externa organisationer
  • University of Edinburgh
  • Smithsonian Tropical Research Institute
  • Pontifical Catholic University of Peru
  • Australian National University
Forskningsområden

Ämnesklassifikation (UKÄ) – OBLIGATORISK

  • Klimatforskning

Nyckelord

Originalspråkengelska
Sidor (från-till)827-838
TidskriftGlobal Change Biology
Volym25
Utgivningsnummer3
Tidigt onlinedatum2019
StatusPublished - 2019
PublikationskategoriForskning
Peer review utfördJa