This study assesses the temporal trends in soil microbial biomass carbon and identifies the main drivers of biomass change regionally and globally. A global soil microbial biomass carbon data set, random forest modelling, and environmental layers were combined to predict spatial-temporal dynamics from 1992 to 2013. Soil microbial biomass carbon stocks decreased globally by 3.4 ±3.0% (mean ± 95% CI), equivalent to 149 Mt being lost. Northern areas with high stocks experienced the strongest decrease, mostly driven by increasing temperatures. Land-cover change had weaker global effects but important regional ones.

Guillaume Patoine, Nico Eisenhauer, Simone Cesarz, Helen R. P. Phillips, Xiaofeng Xu, Lihua Zhang, Carlos A. Guerra