Soil respiration is responsible for up to 90% of terrestrial ecosystem CO2 emissions to the atmosphere — yet the complex nature of the soil system means that soil respiration is one of the most poorly understood ecological processes.
In order to better understand the drivers of soil respiration, Vargas et al. assembled a unique data set consisting of 13 long-term field sites. Each site had a combination of chamber-based and subsurface CO2 flux sensing systems, which were matched with satellite estimates of Gross Primary Productivity (GPP) to provide a full picture of carbon dynamics at the sites.
The robust data set allowed the authors to unveil multiple correlations between temperature, soil water content and GPP and soil respiration, which also revealed several rarely seen seasonal lags between respiration and driving variables. The authors emphasize the need to a variety of measurements, including surface-based and sub-surface measurements of CO2 flux that can be used to disentangle the complex soil processes that lead to terrestrial ecosystem CO2 emissions.
Vargas et al. (2010), Looking deeper into the soil: biophysical controls and seasonal lags of soil CO2 production and efflux