SOM *storage* is not the same as its *vulnerability*. This was a 1-yr incubation experiment from NEON's A and B horizons ran by Tyler Weiglein at Virginia Tech as his Masters degree. We found that predictors of soil carbon vulnerability (based on CO2 respiration) were different for surface and subsurface horizons. Turns out, you need to dig deeper to find out the whole story on soils.