Soil CO2 efflux is considered to mainly derive from biotic activities, while potential contribution of abiotic processes has been mostly neglected especially in productive ecosystems with highly active soil biota. We collected a subtropical forest soil to sterilize for incubation under different temperature (20 and 30 °C) and moisture regimes (30%, 60 and 90% of water holding capacity), aiming to quantify contribution of abiotic and biotic soil CO2 emission under changing environment scenarios. Results showed that abiotic processes accounted for a considerable proportion (15.6−60.0%) of CO2 emission in such a biologically active soil under different temperature and moisture conditions, and the abiotic soil CO2 emission was very likely to derive from degradation of soil organic carbon via thermal degradation and oxidation of reactive oxygen species. Furthermore, compared with biotically driving decomposition processes, abiotic soil CO2 emission was less sensitive to changes in temperature and moisture, causing reductions in proportion of the abiotic to total soil CO2 emission as temperature and moisture increased. These observations highlight that abiotic soil CO2 emission is unneglectable even in productive ecosystems with high biological activities, and different responses of the abiotic and biotic processes to environmental changes could increase the uncertainty in predicting carbon cycling.

中文翻译：

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温度和湿度对亚热带森林非生物和生物土壤CO ₂排放的影响

人们认为土壤CO2的流出主要来自生物活动，而非生物过程的潜在贡献已被大多数人忽略，尤其是在具有高活性土壤生物区系的生产性生态系统中。我们收集了亚热带森林土壤进行灭菌，以便在不同温度（20和30°C）和水分状况（持水量的30％，60和90％）下进行孵化，目的是量化在变化下非生物和生物土壤CO2排放的贡献环境方案。结果表明，在这样的具有生物活性的土壤中，在不同温度和湿度条件下，非生物过程占CO2排放的相当比例（15.6−60.0％），并且非生物土壤CO2的排放很可能来自土壤有机碳的降解。热降解和活性氧的氧化。此外，与以生物方式驱动的分解过程相比，非生物性土壤CO2排放对温度和湿度的变化较不敏感，导致随着温度和湿度的增加，非生物性土壤中CO2排放总量的比例降低。这些观察结果表明，即使在具有高生物活性的生产性生态系统中，非生物土壤CO2的排放也是不可忽略的，并且非生物和生物过程对环境变化的不同响应可能会增加预测碳循环的不确定性。