Abstract:
Soil organic carbon (SOC) is the key to maintain the productivity and sustainability of terrestrial ecosystems. The excessive emission of greenhouse gases (mainly CO
2) leads to the continuous warming of the earth’s climate, which has a profound impact on global SOC. Soil microorganisms are the driving force of SOC turnover and the key agent of global warming affecting SOC storage and chemical properties. It was found that SOC storage of most cropland and forest decreased due to climate warming, but the SOC contents of grassland increased, which maybe relate to the trade-off between dissimilar decomposition and assimilation of organic carbon by microorganisms. The increase of temperature can directly improve the respiratory activities of microorganisms, leading to an increase in the proportion of fungi in soil microorganisms, but a decrease in the proportion of bacteria, which has adverse effects on carbon storage. In permafrost and semi-permafrost, freezing-thawing promoted the release of soil active carbon pools, increased the rate of soil microbial carbon mineralization, and resulted in serious loss of SOC mineralization. However, the increase in temperature and associated CO
2 concentration is beneficial to plant growth, which enhances plant photosynthesis and increases the input of organic carbon into soil. Exogenous organic carbon is transformed into stable SOC under the action of microorganisms, which is beneficial to the SOC accumulation. Despite a large number of researches, the warming overall impact on the SOC and microbial mechanism is still not clear. So the relationship among the “climate - microbes – SOC” should be clarified under the background of global change, in order to provide the basis of theory and policy for “carbon peak” and “carbon neutrality”.