DISCUSSION
Our general analysis of the ecosystem CDMZ model has shown that
the non-evolutionary response of equilibrium SOC to warming always
involves soil carbon loss and may only vary in amplitude (Fig. 1). In
contrast, the evolutionary adaptive response of microbial exoenzyme
allocation, which is shaped by an interaction among the non-linear
temperature dependences of microbial traits, can drive negative as well
as positive responses of equilibrium SOC to warming. The size of
evolutionary effects is most sensitive to MGE, microbial mortality,
activation energy of uptake maximal rate, competition asymmetry, initial
temperature (Fig. 2), and to the traits’ temperature sensitivity (Fig.
3). By specifying the model for five contrasting sites for which
exoenzyme kinetics data are available
(German et al.2012), we find evolutionary aggravation of soil carbon loss to be the
most likely outcome, with a strong latitudinal pattern, from small
evolutionary effects at low latitude to large evolutionary effects at
high latitudes (Fig. 4). Strong temperature-dependence of microbial
mortality, however, would dramatically change the evolutionary pattern,
possibly causing an attenuation of soil carbon loss or even carbon
sequestration in response to warming.