Shifts in pore connectivity from precipitation versus groundwater rewetting increases soil carbon loss after drought. Academic Article uri icon


  • Droughts and other extreme precipitation events are predicted to increase in intensity, duration, and extent, with uncertain implications for terrestrial carbon (C) sequestration. Soil wetting from above (precipitation) results in a characteristically different pattern of pore-filling than wetting from below (groundwater), with larger, well-connected pores filling before finer pore spaces, unlike groundwater rise in which capillary forces saturate the finest pores first. Here we demonstrate that pore-scale wetting patterns interact with antecedent soil moisture conditions to alter pore-scale, core-scale, and field-scale C dynamics. Drought legacy and wetting direction are perhaps more important determinants of short-term C mineralization than current soil moisture content in these soils. Our results highlight that microbial access to C is not solely limited by physical protection, but also by drought or wetting-induced shifts in hydrologic connectivity. We argue that models should treat soil moisture within a three-dimensional framework emphasizing hydrologic conduits for C and resource diffusion.

published proceedings

  • Nat Commun

altmetric score

  • 81.18

author list (cited authors)

  • Smith, A. P., Bond-Lamberty, B., Benscoter, B. W., Tfaily, M. M., Hinkle, C. R., Liu, C., & Bailey, V. L.

citation count

  • 75

complete list of authors

  • Smith, A Peyton||Bond-Lamberty, Ben||Benscoter, Brian W||Tfaily, Malak M||Hinkle, C Ross||Liu, Chongxuan||Bailey, Vanessa L

publication date

  • January 2017