Soil microbial residues, refractory organic matter formed by microbial metabolism, are important components of soil organic carbon pools. However, little is known about the large-scale spatial patterns of bacteria- and fungi-derived soil organic carbon and the underlying driving mechanisms.

An recent investigation led by Researcher Wang Qingkui from the Forest Plantation Ecology Group of the Institute of Applied Ecology of the Chinese Academy of Sciences examined spatial distribution patterns and drivers of soil fungal and bacterial residues along the eastern forest transect in China.

The researchers found that microbial residues are important sources of forest soil organic carbon pools, the forest soil organic carbon is derived more from fungal residues than bacteria residues, and the proportions of the fungi- and bacteria-derived carbon are lower in boreal forests than in forests at lower latitudes. The average annual temperature is the main factor regulating the horizontal spatial pattern of the bacteria-derived carbon, while the ratio of carbon to nitrogen (carbon availability) is a key factor controlling the horizontal distribution of the fungi-derived carbon.

This study indicates that the fungi- and bacteria-derived carbon should be separately assessed when simulating the land carbon cycle models.  

This study, funded by the National Natural Science Foundation of China, has been published in Global Ecology and Biogeography entitled "Mean annual temperature and carbon availability respectively controlled the contributions of bacterial and fungal residues to organic carbon accumulation in topsoil across China's forests."