Tradeoffs among microbial life history strategies influence the fate of microbial residues in subtropical forest soils

Microbial residues play a significant role in the formation of soil organic matter (SOM), but it is not clear how microbial traits influence residue accrual and SOM persistence. By pairing microbial biomarker and genomics approaches, we tested whether microbial life history strategies and residue accrual differed between primary (similar to 70-year-old) and secondary (similar to 30-year-old) subtropical forests. We found that microbial residue concentrations were significantly higher in secondary than primary forests, and strongly associated with several abundant microbial taxa (Ascomycota, Proteobacteria, Gemmatimonadetes). Microbial communities inhabiting resource-rich secondary forests were also associated with high growth yields and soil organic carbon (SOC) accrual (through residue retention), while nutrient-limited primary forests were dominated by microorganisms employing resource-acquisition strategies. We therefore suggest microbial life history traits can be used to link microbial community composition and metabolic processes with the turnover and transformation of SOC.

Automated summary

The study found that microbial residue concentrations were significantly higher in secondary forests and strongly associated with several abundant microbial taxa, such as Ascomycota, Proteobacteria, Gemmatimonadetes. Microbial communities in resource-rich secondary forests were also associated with high growth yields and soil organic carbon accrual, while nutrient-limited primary forests were dominated by microorganisms employing resource-acquisition strategies. This suggests that the microbial life history traits can be used to link microbial community composition and metabolic processes with the turnover and transformation of soil organic carbon.