title: Thermal adaptation of soil microbial respiration to elevated temperature.
abstract: In the short-term heterotrophic soil respiration is strongly and positively related to temperature. In the long-term, its response to temperature is uncertain. One reason for this is because in field experiments increases in respiration due to warming are relatively short-lived. The explanations proposed for this ephemeral response include depletion of fast-cycling, soil carbon pools and thermal adaptation of microbial respiration. Using a > 15 year soil warming experiment in a mid-latitude forest, we show that the apparent 'acclimation' of soil respiration at the ecosystem scale results from combined effects of reductions in soil carbon pools and microbial biomass, and thermal adaptation of microbial respiration. Mass-specific respiration rates were lower when seasonal temperatures were higher, suggesting that rate reductions under experimental warming likely occurred through temperature-induced changes in the microbial community. Our results imply that stimulatory effects of global temperature rise on soil respiration rates may be lower than currently predicted.
authors.affiliation: Odum School of Ecology, University of Georgia, Athens, GA 30602, USA. markb@uga.edu
authors.forename: Mark A
authors.initials: MA
authors.lastname: Bradford
authors.forename: Christian A
authors.initials: CA
authors.lastname: Davies
authors.forename: Serita D
authors.initials: SD
authors.lastname: Frey
authors.forename: Thomas R
authors.initials: TR
authors.lastname: Maddox
authors.forename: Jerry M
authors.initials: JM
authors.lastname: Melillo
authors.forename: Jacqueline E
authors.initials: JE
authors.lastname: Mohan
authors.forename: James F
authors.initials: JF
authors.lastname: Reynolds
authors.forename: Kathleen K
authors.initials: KK
authors.lastname: Treseder
authors.forename: Matthew D
authors.initials: MD
authors.lastname: Wallenstein
mesh_terms: D000222:Adaptation, Physiological / Q000502:physiology*; D018533:Biomass; D006358:Hot Temperature; D012044:Regression Analysis; D012621:Seasons; D012987:Soil / Q000032:analysis; D012988:Soil Microbiology
chemical_list: D012987:Soil