Here check this out:

[Deinococcus radiodurans](http://en.wikipedia.org/wiki/Deinococcus_radiodurans)

>Deinococcus has been genetically engineered for use in bioremediation to consume and digest solvents and heavy metals, even in a highly radioactive site. For example, the bacterial mercuric reductase gene has been cloned from Escherichia coli into Deinococcus to detoxify the ionic mercury residue frequently found in radioactive waste generated from nuclear weapons manufacture. Those researchers developed a strain of Deinococcus that could detoxify both mercury and toluene in mixed radioactive wastes.

This tells me that bacteria's appearance in the nature plays a significant role in detoxification and balancing of the environment to sustain life, therefore I could fathom that they will handle the excess carbon in soil or atmosphere similarly (in chorus with plants).

This also tells me, that inferences made about anything on the issue of soil and CO2 and plants and bacteria needs serious attentions to the genome and molecular structure of bacteria, and one cannot just infer claims leaving this most important fact out of the picture.

And if we do, that is crackpot science.