A new study titled Is the rate of mineralization of soil organic carbon under microbiological control? suggests that:
- the rate limiting step in SOC mineralization is abiotic (physical rather than biological).
- that mineralization of SOC may be a two-stage process: firstly, non-bioavailable forms are converted abiologically to bioavailable forms, which, only then, undergo a second process, biological mineralization.
I’ll speculate and say that mineralization is perhaps limited by dissolved organic matter in the form of complex carbon structures that are produced by weathering, oxidation, and detritivores that break apart plant litter. Liquid compounds that tend to be lost when composting.
Compounds that are probably why wet climates and seagrasses sequester the most carbon.
Why drying and wetting of these compounds leads to CO2-Bursts.
Compounds we should be trying to keep in the soil profile doing good, and not in aquifers or waterways creating algal blooms, like we really need to with this recently discovered underground molten lake the size of Mexico!
That depending on the complexity of the carbon molecule as it gets passed down the soil carbon continuum food web it may be more than a two-stage process, with more than one in both the physical and biological realms based upon chemical energy and chemisorption of the carbon compounds.
*shrugs* Just my guess, I suck at chemistry.