Do the respiration pulses induced by drying-rewetting matter for the soil-atmosphere carbon balance?

Abstract

We show that the explosive microbial and biogeochemical dynamics triggered by rewetting dry soil in laboratory experiments also has relevance in intact ecosystems. This highlights an opportunity to use predictions derived from laboratory studies to provide targets in ecosystem-scale biogeochemical studies.

Keywords: birch effect; carbon cycling; climate change; ecosystem drought; ecosystems; eddy covariance; soil microorganisms; soil moisture.

FIGURE 1

Conceptual figure showing the insights of soil–atmosphere C exchange at different scales. Panel (a): Conceptual representation of the influence of the patterns of drying–rewetting (upper box) on microbial respiration (lower box). Panel (b): Schematic representation of how the “intensity of dry period” (in orange), the “intensity of rewetting” (in blue), the “length of dry period” (in yellow), and the “number of cycles” of drying–rewetting (in green) affect the respiration rates, based on microbially targeted literature. Panel (c): Example of the ecosystem‐level C fluxes measured in an eddy covariance tower located in the Pianosa Island in Italy in 2003 (Inglima et al., 2009). Vertical bars represent daily precipitation (upper box) and the solid line shows changes in soil moisture (upper box), and daily net ecosystem exchange (lower box)