Cyanobacterial- and moss-forming biocrusts consistently mitigate the temperature sensitivity of microbial respiration along a continental precipitation gradient

1. Biocrusts are prevalent and participate in many soil organic carbon (C) processes in drylands. The predicted increase in aridity will expand the biocrust cover and significantly impact soil organic C dynamics. However, how biocrusts change soil organic C decomposition and what factors drive the effect in response to climate warming remains largely unknown at a continental scale.
2. We measured microbial respiration and its temperature sensitivity (Q10) in bare soil lacking biocrusts and two universal biocrusted soils (cyanobacterial- and moss-crusted soil) from 43 sites across a precipitation gradient from 39 mm to 443 mm to evaluate the relative effects of biocrusts on Q10 and the driving forces in northern China’s dryland.
3. Microbial respiration increased and Q10 decreased with increasing precipitation in bare soil, cyanobacterial- and moss-crusted soil. Biocrusts positively affected microbial respiration, with a more substantial magnitude by moss crusts than cyanobacterial crust...