微生物如何驱动土壤有机质形成？

Title：
Direct evidence for microbial-derived soil organic matter formation and its ecophysiological controls

DOI：
10.1038/ncomms13630

Abstract：
Soil organic matter (SOM) and the carbon and nutrients therein drive fundamental submicron- to global-scale biogeochemical processes and influence carbon-climate feedbacks. Consensus is emerging that microbial materials are an important constituent of stable SOM, and new conceptual and quantitative SOM models are rapidly incorporating this view. However, direct evidence demonstrating that microbial residues account for the chemistry, stability and abundance of SOM is still lacking. Further, emerging models emphasize the stabilization of microbial-derived SOM by abiotic mechanisms, while the effects of microbial physiology on microbial residue production remain unclear. Here we provide the first direct evidence that soil microbes produce chemically diverse, stable SOM. We show that SOM accumulation is driven by distinct microbial communities more so than clay mineralogy, where microbial-derived SOM accumulation is greatest in soils with higher fungal abundances and more efficient microbial biomass production.

All Authors：
Cynthia M Kallenbach,Serita D Frey,A Stuart Grandy

First Authors：
Kallenbach CM

Correspondence：
Grandy AS

内容要点：

1、土壤有机质(SOM)和碳及其养分驱动着基本的超微生物地球化学过程，并影响碳循环-气候反馈；

2、微生物成分是稳定SOM的重要组成部分已是共识，但证明微生物残留成分直接解释SOM的化学组成，稳定性和丰度的证据仍然缺乏，而且微生物生理对微生物残渣生产的影响也不清楚；

3、本文直接证明土壤微生物可产生化学多样性和稳定的SOM，SOM的积累是由不同微生物菌群驱动，粘土矿物中微生物驱动的SOM积累最大，且真菌丰度高，生物量生产更高效。