Data from: Cross-biome patterns in soil microbial respiration predictable from evolutionary theory on thermal adaptation

Climate warming may stimulate microbial metabolism of soil carbon, causing
a carbon cycle-climate feedback whereby carbon is redistributed from soil
to atmospheric CO2. The magnitude of this feedback is uncertain, in part
because warming-induced shifts in microbial physiology and/or community
composition could retard or accelerate soil carbon losses. Here, we
measure microbial respiration rates for soils collected from 22 sites in
each of three years, at locations spanning boreal to tropical climates.
Respiration was measured in the laboratory with standard temperatures,
moisture and excess carbon substrate, to allow physiological and community
effects to be detected independent from the influence of these abiotic
controls. Patterns in respiration for soils collected across the climate
gradient are consistent with evolutionary theory on physiological
responses that compensate for positive effects of temperature on
metabolism. Respiration rates per unit microbial biomass were as much as
2.6-times higher for soils sampled from sites with a mean annual
temperature (MAT) of -2.0 versus 21.7ºC. Subsequent 100-day incubations
suggested differences in the plasticity of the thermal response among
microbial communities, with communities sampled from sites with higher MAT
having a more plastic response. Our findings are consistent with adaptive
metabolic responses to contrasting thermal regimes that are also observed
in plants and animals. These results may help build confidence in soil
carbon-climate feedback projections by improving understanding of
microbial processes represented in biogeochemical models.