Warm soils change microbes, not Q10 of respiration
Along a >31°C geothermal gradient in New Zealand, bacterial and fungal communities shifted but MMRT temperature-sensitivity of soil respiration showed no thermal adaptation.
Source
Soil microbial sensitivity to temperature remains unchanged despite community compositional shifts along geothermal gradients
What they did
Soils from grassland and kānuka biomes at several distances from a heated depression were incubated across temperatures; 35 respiration curves were fit with MMRT and Lloyd–Taylor, and 16S/ITS communities were sequenced.
What they found
Mean environmental temperature ranged from 16.9°C to 48.3°C. Community composition differed by biome and by distance from heat. Authors found no evidence for thermal adaptation of SOM decomposition despite those community shifts.
The limits
What it doesn't show
Some Topt estimates (up to 103°C) are biologically implausible, so MMRT parameters can be biased; geothermal gradients also alter pH and C:N, not temperature alone.
Key terms
- MMRT
- Macromolecular rate theory describing curved temperature responses of enzyme-catalyzed respiration.
- Thermal adaptation
- Down-regulation of relative temperature sensitivity after long-term warming.
- MET
- Mean environmental temperature of the soil at the sampling location.
- Topt
- Temperature of peak respiration inferred from MMRT.
- SOM respiration (Rs)
- CO2 production from microbial decomposition of soil organic matter.
Flashcards
Research intelligence for this paper
See its role on concept claims, tensions it is part of, placement history, and related discoveries.
Quiz yourself
Thermal adaptation of SOM respiration was:
Common questions
Did communities change with warming?
Yes—bacteria and fungi differed with distance from the heat source.
Did temperature sensitivity adapt?
No evidence for thermal adaptation of SOM decomposition.
Temperature range?
MET from 16.9°C to 48.3°C (>31°C span).
Site?
Taupō Volcanic Zone, New Zealand.
More on Carbon cycle