Effects of Warming and Increased Precipitation on Soil Microbial Residues on the Qinghai–Tibet Alpine Meadows

Abstract

Abstract. Amino sugars, as the biomarkers of microbial residues, help explore soil microorganisms’ response to global climate change. However, research on how microorganisms in the alpine meadows regulate the soil carbon cycle under the influence of climate change is limited. We hypothesized that climate change might cause different effects on soil microbial residues due to the impact on soil physical properties, chemical properties, and enzyme activities. Therefore, we conducted four-year continuous warming and increased precipitation experiments in the semi-arid grasslands to examine the differences in soil microbial residues at different depths under simulated changes. The results showed warming stimulated the accumulation of microbial residues, while increased precipitation led to their decline. The Glucosamine/Muramic Acid ratio trend indicates that the contribution of fungal residues was more significant than that of bacteria with increased precipitation, whereas that of bacterial residues exceeded that of fungi with warming. The increased precipitation had no significant effect on soil extracellular enzyme activities and amino sugar concentrations. In addition, changes in the different enzyme activities led to soil carbon loss and different amino sugar accumulation patterns under the warming treatment. These results may aid in assessing the responses of soil microorganisms to future climate change scenarios.