Zhang Rui, Li Rong, Kuang Jialiang, Shi Zhenqing
School of Environment and Energy, South China University of Technology, Guangzhou, Guangdong 510006, People's Republic of China; The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, South China University of Technology, Guangzhou, Guangdong 510006, People's Republic of China.
School of Environment and Energy, South China University of Technology, Guangzhou, Guangdong 510006, People's Republic of China; The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, South China University of Technology, Guangzhou, Guangdong 510006, People's Republic of China.
Sci Total Environ. 2024 Jan 15;908:168362. doi: 10.1016/j.scitotenv.2023.168362. Epub 2023 Nov 7.
Global climate change can affect the soil thermal and moisture condition, potentially disrupting microbial-mediated soil respiration and altering the soil C cycle. However, the complex relationship between the soil C turnover and transient thermal and moisture conditions is not fully understood. Specifically, quantitative understanding is lacking regarding the impact of drought-rewetting events and temperature on the response of soil organic carbon (SOC) decomposition rate to exogenous C input, known as the priming effects (PEs). Herein, we quantified glucose-induced PEs during the rewetting of soils incubated under two drought intensities [with 20 % and 33 % water holding capacity (WHC)], at different incubation temperatures (15, 25, and 35 °C). Moreover, the effect size of drought intensities on PEs and the temperature sensitivity of PEs were quantified using lnRR (Response Ratio) and Q of PEs. Glucose input triggered positive PEs after 21 d incubation and increased SOC decomposition by 29.7-72.7 %. Drought intensity showed positive effect (lnRR > 0) on PEs at lower temperatures (15 and 25 °C) but showed negative effect (lnRR < 0) on PEs at higher temperature (35 °C). At moderate drought intensity (33 % WHC) before rewetting, PEs increased significantly with incubation temperature (Q = 1.65). Contrastingly, at high drought intensity (20 % WHC), temperature did not significantly influence PEs during the 21-d incubation after rewetting (Q = 0.96). The combination of drought, temperature change and glucose addition significantly changed the abundances in the dominant bacterial phyla (Proteobacteria, Actinobacteria, and Chloroflexi) and fungal phylum (Ascomycota), which likely affect PEs. Furthermore, the decrease in the demand for microbial-driven N mining, which is a crucial factor in promoting positive PEs, was associated with drought intensity at high temperature (35 °C). Our study provided a quantitative and mechanistic understanding of the impact of drought intensity on PEs before rewetting and its temperature sensitivity.
全球气候变化会影响土壤的热状况和湿度条件，有可能扰乱微生物介导的土壤呼吸并改变土壤碳循环。然而，土壤碳周转与瞬时热状况和湿度条件之间的复杂关系尚未完全明晰。具体而言，对于干旱-复湿事件和温度对土壤有机碳（SOC）分解速率对外源碳输入的响应（即激发效应，PEs）的影响，仍缺乏定量认识。在此，我们量化了在两种干旱强度[持水量（WHC）分别为20%和33%]下培养的土壤复湿过程中葡萄糖诱导的激发效应，实验设置了不同的培养温度（15、25和35°C）。此外，利用激发效应的lnRR（响应比）和Q值量化了干旱强度对激发效应的影响大小以及激发效应的温度敏感性。葡萄糖输入在培养21天后引发了正激发效应，使SOC分解增加了29.7 - 72.7%。干旱强度在较低温度（15和25°C）下对激发效应表现出正效应（lnRR > 0），但在较高温度（35°C）下对激发效应表现出负效应（lnRR < 0）。在复湿前处于中度干旱强度（33% WHC）时，激发效应随培养温度显著增加（Q = 1.65）。相反，在高干旱强度（20% WHC）下，复湿后21天的培养过程中温度对激发效应没有显著影响（Q = 0.96）。干旱、温度变化和葡萄糖添加的组合显著改变了优势细菌门（变形菌门、放线菌门和绿弯菌门）和真菌门（子囊菌门）的丰度，这可能影响激发效应。此外，微生物驱动的氮素开采需求的降低是促进正激发效应的关键因素，这与高温（35°C）下的干旱强度有关。我们的研究对复湿前干旱强度对激发效应的影响及其温度敏感性提供了定量和机理上的理解。
