Global change effects on microbial-mediated soil organic carbon cycling processes

作者：Junxi Hu · 年份：2024 · DOI：10.5463/thesis.708 · 被引用次数：1 · 研究领域：Soil Carbon and Nitrogen Dynamics

Soil microorganisms, including bacteria, fungi, and archaea, are the main actors of global C cycling. Global change factors, such as nitrogen deposition, warming, and elevated CO2 (eCO2), can influence microbial communities and, consequently, carbon pools in the soil. Understanding the microbial community's response to global change factors is crucial for predicting and managing soil carbon cycling. Such understanding is important for efforts to maximize soil carbon storage in order to reduce the earth's surface carbon emissions and associated climate warming. In this PhD thesis, my primary focus lies on 1) investigating the response of microbial carbon use efficiency and the resulting necromass to anthropogenic nitrogen enrichment; 2) exploring the influence of global change factors, including climate warming and elevated CO2, on microbial necromass in soil and its consequential impact on the formation of associated soil organic matter; 3) unraveling the global patterns and drivers of microbial CUE in soil. I generally used a global meta-analysis approach to test hypotheses about microbial attributes’ responses to global changes. In Chapter 3, I assessed the impact of anthropogenic nitrogen (N) enrichment on microbial Carbon Use Efficiency (CUE; the ratio of the C amount used for growth to the C taken up) within the ecosystem. The results revealed a notable enhancement in microbial growth rate and CUE, particularly when applying the 18O-labelled water approach. This increase...