The Whole-Soil Carbon Flux In Response To Warming

  • Sites: US-Blo
  • Hicks Pries, C. E.; Castanha, C.; Porras, R. C.; Torn, M. S. (2017/03/31) The Whole-Soil Carbon Flux In Response To Warming, Science, 355(6332), 1420-1423.
  • Funding Agency: DOE

  • Soils contain about twice as much carbon as Earth’s atmosphere, so their response to warming is crucial to understanding carbon fluxes in a changing climate. Past studies have heated soil to a depth of 5 to 20 cm to examine such fluxes. Hicks Pries et al. heated the ground to a depth of 100 cm. Extending measurements to that depth revealed that 4°C of warming increased annual soil respiration by 34 to 37%—a considerable amount more than previously observed.

    Soil organic carbon harbors three times as much carbon as Earth’s atmosphere, and its decomposition is a potentially large climate change feedback and major source of uncertainty in climate projections. The response of whole-soil profiles to warming has not been tested in situ. In a deep warming experiment in mineral soil, we found that CO2production from all soil depths increased with 4°C warming; annual soil respiration increased by 34 to 37%. All depths responded to warming with similar temperature sensitivities, driven by decomposition of decadal-aged carbon. Whole-soil warming reveals a larger soil respiration response than many in situ experiments (most of which only warm the surface soil) and models.